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U.S. DEPARTMENT OF COMMERCE

National Bureau of Standards

NBSIR 85-3232

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RESEARCH INFORMATION CENTER

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Radiation

Research

October 1985

U.S. DEPARTMENT OF COMMERCE

National Bureau of Standards
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ABSTRACT

This report summarizes research projects, measurement method development,

calibration and testing, and data evaluation activities that were carried

out during Fiscal Year 1985 in the NBS Center for Radiation Research.

These activities fall in the areas of atomic and plasma radiation,

radiation physics, radiometric physics, radiation sources and

instrumentation, ionizing radiation, and nuclear physics.

Key Words: Atomic radiation, ionizing radiation; measurement support;

nuclear radiation; plasma radiation; radiation

instrumentation, radiation measurements; radiation physics,

radiation sources; radiometric physics.

l
INTRODUCTION

This report is a summary of the technical activities of the NBS

Center for Radiation Research (CRR) for the period October 1, 1984 to

September 30, 1985. The Center is one of four Centers in the National

Measurement Laboratory.

The Center for Radiation Research develops and maintains the

scientific competences and experimental facilities necessary to provide

the Nation with a central basis for uniform physical measurements,

measurement methodology, and measurement services in the areas of near infra-red radiation, optical (visible) radiation, ultraviolet radiation,

and ionizing radiation (x rays, gamma rays, electrons, neutrons,

radioactivity, etc.); provides government, industry, and the academic

community with essential calibrations for field radiation measurements

needed in such applied areas as nuclear power, lighting, solar

measurements, aerospace, defense, color and appearance, health care,

radiation processing, advanced laser development, and radiation protection

for public safety; carries out research in order to develop improved

radiation standards, new radiation measurement technology, and improved

understanding of atomic, molecular, and nuclear radiation processes, and

to elucidate the interaction of radiation and particles (electrons,

neutrons, and ions) with inanimate and biological materials; collects,

compiles, critically evaluates, and supplements the existing atomic,

molecular, and nuclear data bases in order to meet the major demands of

the Nation for such data; and participates in collaborative efforts with

other NBS centers in the interdiscipl inary applications of radiation.

The summary of activities is organized into six parts, one for each

of the five Divisions in the Center: Atomic and Plasma Radiation,

Radiation Physics, Radiometric Physics, Radiation Sources and

Instrumentation, and Ionizing Radiation, and one for the Nuclear Physics

Group. A major subgroup of the Ionizing Radiation Division is the Office

of Radiation Measurement. Each organizational unit tells its own story in

its own way. In general there is an introduction followed by a series of

short reports on current activities, publications during the year, talks

given, committee participation, and professional interactions.

A detailed table of contents has been provided to permit the reader

to find those activities of greatest interest. To obtain more information

about particular work, the reader should address the individual scientists

or their division, c/o Center for Radiation Research, Radiation Physics

Building, C229, National Bureau of Standards, Gaithersburg, MD 20899.
Table of Contents

ABSTRACT i

INTRODUCTION ii

CRR ORGANIZATION CHART vi i

ATOMIC AND PLASMA RADIATION - Division 531 1

Atomic Spectroscopy Group 3

Atomic Radiation Data Group 6

Plasma Radiation Group 9

Sponsored Workshops, Conferences, and Symposia 13

Invited Talks 14

Publications 15

Publications in Preparation 19

Technical & Professional Committee Participation & Leadership .... 22

Major Consulting and Advisory Services 24

Journal Editorships 26

Trips Sponsored by Others 27

Calibration Services Performed 28

Sponsored Seminars and Colloquia 29

RADIATION PHYSICS - Division 533 31

Far Ultraviolet Physics Group 35

Electron Physics Group 46

Sponsored Workshops, Conferences, and Symposia 52

Invited Talks 53

Publications 57

Publications in Preparation 61

ii i
Technical & Professional Committee Participation & Leadership .... 63

Major Consulting and Advisory Services 66

Journal Editorships 67

Trips Sponsored by Others 68

Calibration Services Performed 71

Sponsored Seminars and Colloquia 72

RADIOMETRIC PHYSICS - Division 534 75

Spectroradiometry and Optical Pyrometry Group 79

Spectrophotometry Group 84

Photodetector Physics and Metrology Group 88

Radiometric Measurement Services 94

Sponsored Conferences 96

Invited Talks 97

Publications 99

Publications in Preparation 101

Technical & Professional Committee Participation & Leadership ... 102

Standards Committee Meetings 105

Standards Writing 106

Major Consulting and Advisory Services 107

Standard Reference Materials 109

Measurement Assurance Services Ill

Calibration Services Performed 112

Trips Sponsored by Others 113

Sponsored Seminars and Colloquia 114

i v
RADIATION SOURCE AND INSTRUMENTATION - Division 535 115

CW Accelerator Research (Microtron) 115

Linac Operations 139

Instrumentation Services 143

Radiation Instrumentation Standards 146

Invited Talks 149

Publications 150

Technical & Professional Committee Participation & Leadership .... 151

Major Consulting and Advisory Services 154

Sponsored Seminars and Colloquia 155

IONIZING RADIATION DIVISION - Division 536 157

Office of Radiation Measurement 159

Radiation Theory Group 164

Radiation Chemistry & Chemical Dosimetry Group 169

Neutron Mesurements & Research Group 173

Neutron Dosimetry Group 183

Radioactivity Group 190

X-Ray Physics Group 200

Electron & Photon Dosimetry Group 206

Sponsored Workshops, Conferences, and Symposia 210

Invited Talks 211

Publications 216

Publications in Preparation 225

Technical & Professional Committee Participation & Leadership 230

Major Consulting and Advisory Services 240

v
Journal Editorships 251

Trips Sponsored by Others 252

Standard Reference Materials 255

Calibration Services Performed 257

Sponsored Seminars and Colloquia 260

NUCLEAR PHYSICS GROUP - 530.1 261

Invited Talks 268

Publications 271

Publications in Preparation 273

Technical & Professional Committee Participation & Leadership 274

Journal Editorships 276

Trips Sponsored by Others 277

Sponsored Seminars and Colloquia 279

vi
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TECHNICAL ACTIVITIES

Division 531, Atomic and Plasma Radiation

Task No. 15211 - Atomic Radiation Data and Standards

Task No. 15212 - Atomic Processes in Plasmas

The Atomic and Plasma Radiation Division carries out a broad range of

experimental and theoretical research on atomic structure and atomic

radiation in plasmas. The division determines a large variety of atomic

radiation and collision data, encompassing wavelengths of spectral lines;

atomic energy levels; ionization potentials; atomic transition probabilities; plasma line broadening parameters; ionization and excitation cross sections and rate coefficients, and dielectronic rate coefficients. Two

data centers located in the division critically evaluate and compile

atomic energy levels and transition probabilities. The division is also

engaged in research on the interaction of atomic radiation with plasma

environments, and it explores such effects for the development of new measurement techniques. Furthermore, well-defined atomic radiation

sources are developed as VUV radiometric standards or wavelength standards .

These activities support several areas of science and technology.

A good deal of our work ties into magnetic fusion research, where atomic

data are needed for studies of the effects of heavy ion impurities and

where atomic radiation processes are utilized as non-i nterferi ng plasma

probes. Other areas of direct applications are parts of the Strategic

Defense Initiative (SDI), vacuum ultraviolet and x-ray laser development,

and space astronomy and solar physics. In all these areas, atomic

radiation data are one of the basic ingredients, and plasma measurement

techniques utilizing the emitted radiation are applied. Our vacuum ultraviolet radiometry work is now, for the first time, providing small

calibrated radiation source packages to allow radiometric calibrations on board spacecraft, which are used, for example, on the space shuttle for

accurate monitoring of the solar ultraviolet radiation, and are part of

the space telescope instrumentation.

The division consists of three technical groups: Atomic Spectroscopy, Atomic Radiation Data, and the Plasma Radiation Groups. The

division currently has 21 professional physicists, among them 18 Ph.D.s,

plus 1 IPA. During 1985 the division has had 8 guest scientists from

China (2), France, India, Germany (2), and Yugoslavia (2).

During the past year several of our projects again produced

significant accomplishments, among them:

1
Division 531, Technical Activities (cont'd.)

® the analysis of spectra of Ne-like highly stripped ions for

x-ray laser research

o laser wavelength measurements with a computerized Fabry-Perot

interferometer system at a precision of about 1 part in 10 9

® the convening of an atomic theory workshop on relativistic and

QED effects to explore new directions in theoretical atomic

physi cs

o the calculation of dielectronic recombination rates for Li, 0,

F, and Ne-like ions with the only comprehensive production code

in existence anywhere

« first measurements of excitation rates for impurity ions with a tokamak device (TEXT tokamak)

® comprehensive tests and irradiafice calibrations of special low

intensity VUV sources for the faint object spectrograph on the

Space telescope

These and others will be discussed in some detail in the following

sections, where the principal work of the three technical groups during

the last year is described.

2
Division 531, Technical Activities (cont'd.)

I , Atomic Spectroscopy Group

(a) Highly Ionized Atoms--With the recent announcement by the

Lawrence Livermore National Laboratory of an X-ray laser scheme based on Ne-like selenium transitions, a great deal of interest has arisen on spectral data of Ne-like spectra of highly stripped ions. We have, therefore, excited and identified n = 3-3 transitions in the Ne-like ions of

Ca, Sc, Ti, and V. This work, carried out in collaboration with a Swedish

group, also gives data of interest for plasma physics and astrophysics.

In addition, we completed measurements and energy-level classifications

for the spectra of the ten copper ions Cu 11+ through Cu 20+

. Similar

spectra have been recorded for ions of Zn, Ga, Ge, and As, and will be

analyzed soon.

We were able to identify lines of the Na-like ion Sr27+ in

spectra of a 1 aser-produced plasma. The identifications gave 26 energy

levels of the ns, np, nd, nf and ng configurations. Comparisons of these

results with calculations give significant tests of the accuracy of the

theory for the Na i soel ectronic sequence, including relativistic contributions .

We are making arrangements for experiments to obtain spectra of

very highly ionized atoms using the OMEGA laser at Rochester. Our goal is

to reach ionization stages of interest for the very high temperature

fusion plasmas anticipated for the Princeton Tokamak Fusion Test Reactor

and JET-Tokamak, as well as for x-ray laser physics (n=2 shell ions of

atoms Z > 38) .

(b) Wavelength Standards- -We have measured the wavelengths of

selected lines of singly ionized Hg 198 with accuracies of a few parts in

10 7

. These results allowed location of a basic Hg+ two-photon transition

in ion-trap research in Boulder and also give Ritz-type Hg+ wavelength

standards in the vacuum-ultraviolet region 90-200 nm. Our measurements of

the spectrum of a platinum hollow-cathode discharge for the VUV and UV

region 110-330 nm are almost complete. Wavelengths for almost 3000 transitions have been determined with uncertainties of ±0.0002 to ±0.0003 nm. These data will be used for on-board calibration of the high-resolution

spectrograph for the Space Telescope and also provide standards for highresolution laboratory spectroscopy. Our work giving new accurate Ritztype standard wavelengths of Y 5+ in the XUV region 20-40 nm has been

completed. These wavelengths are derived from an extensive system of

energy levels as obtained from a very complete analysis of this spectrum.

Together with our previous Y 3+ determinations and Y 4+ work in progress,

these wavelengths comprise a system of yttrium standards for the range

18-70 nm.

3
Division 531, Technical Activities (cont'd.)

(c) Atomic Photoabsorption in the XUV Region- -A manuscript was completed on the Cs + absorption spectrum as observed through a Cs + plasma

produced by laser pumping. We identified the 5p5 ns and 5p5 nd series both

above and below the 5p

5 2

P 3/ o ionization threshold ( 5p

6 1 S

0 - 5p5 ns, nd

transitions, 50-60 nm region). An observed peculiar intensity behavior of

these series below threshold was interpreted on the basis of a periodicity

in the multichannel quantum-defect theory Lu-Fano plot.

We also extended our analysis of Ba2+ absorption to the belowthreshold region to reveal channel interactions through intensity anomalies. This project is now almost completed.

A theoretical interpretation of photoabsorption in the 3d shell

in the rare-earth elements Ce, Pr, Ho, and Er was completed. This work

was done in collaboration with groups from the Free University of Berlin

and from the Lawrence Berkeley Laboratory who obtained the data at the

Stanford Synchrotron Radiation Laboratory.

(d) Laser SpectroscopyWe have previously demonstrated that laser

wavelength measurements made with a Fabry-Perot interferometer illuminated

with uncollimated (extended source) light are free of certain systematic

errors difficult to eliminate from travel i ng-mi rror wavemeters. We have

now implemented computer acquisition of Fabry-Perot fringe patterns from a semiconductor array detector with real-time processing. Currently the

patterns are analyzed at a rate of 1.4 Hz. Thermal drifts of the interferometer length are taken into account by alternately sampling the laser

to be measured and a reference laser; thus the system makes a new determination of the unknown wavelength every 1.5 seconds. We have obtained a precision of 1 part in 10 9 for measurements of the reference laser against

itself, averaged over 10 determinations. In initial tests an accuracy of

better than 3 parts in 10 8 has been confirmed by measurements of (Doppler

broadened) uranium lines that we had previously measured to this

accuracy

.

We are now progressing to use these new measurement techniques

to make precise observations of Li Rydberg states by a Doppler-free threephoton technique. We have made preliminary observations of the 2s-3s twophoton transition and of a number of 2s-3s-np three-photon transitions.

Further progress in this experiment has been temporarily delayed by

difficulty in obtaining appropriate dye-laser optics. In the meantime we have used the apparatus developed for this experiment to study multiphoton

"quasi resonant" ionization of Li at low laser powers. This effect has

been observed using broad band dye lasers in other alkali metals and a number of possible mechanisms have been discussed. In Li we observe the

effect with a single-mode laser and find strong dependence on the laser

tuning at a resolution not obtainable with broad-band lasers. This

suggests that we should be able to probe the details of the ionization

mechanism, and experiments for this purpose are being prepared.

4
Division 531, Technical Activities (cont'd.)

We are also investigating low-pressure electric discharges to

find conditions giving minimal collisional transfer of atomic level

excitations. Such discharges are needed for applications of doubleresonance laser spectroscopic techniques to analyze complex atomic level

structures

.

(e) Atomic Energy Levels Data Center- -We began a program of atomic

spectral wavelength compilations with the most extensive compilation of

data for (forbidden) magnetic dipole transitions ever carried out. The

data include more than 1400 observed and predicted wavelengths for atoms

and (mainly) ions of the elements B through Mo (Z=5-42) and also include

calculated transition probabilities. These data tables, which are of

great importance for plasma physics and astrophysics, now have been

submitted for publication. We plan to compile al 1 owed lines of many

spectra with wavelengths and energy-level classifications based on our

critical reviews of the analyses.

Our energy-level compilations for the 235 spectra of the i ron- group elements K through Ni (Z=19-28) are finished and will be published

soon as a new volume of atomic energy levels. A compilation for the 15

spectra of phosphorus has also been completed. We are now critically

reviewing and compiling data on energy levels for the spectra of sulfur,

chlorine, and molybdenum. The results of new calculations, theoretical

i nterpretations, and even observations stimulated by our reviews are often

included in our published compilations.

We monitor the literature on atomic energy levels, wavelengths,

wavefunctions, etc., and the resulting reference files and published

bibliographies are used by a wide clientele. The third supplement to our Bibliography on Atomic Energy Levels and Spectra, covering the literature

from July 1979 through December 1983, was published this year.

5
Division 531, Technical Activities (cont'd.)

II . Atomic Radiation Data Group

The work of this group is entirely theoretical and consists of two

major areas: (1) theoretical studies of atomic structure and processes,

and (2) critical evaluation and compilation of atomic transition probability and spectral line shape data. The first activity involves the

development of advanced theoretical methods and their implementation to

calculate atomic data. The main areas of activity have been dielectronic

recombination, relativistic quantum mechanics, electron correlation, and

radiative and collisional transition rates. The critical evaluation and

compilation of transition probability and spectral line shape data takes

place in the Data Center on Atomic Transition Probabilities, which also

maintains an up-to-date bibliography of the literature in these fields.

(a) Theoretical Studies

One of the highlights of the year was an atomic theory workshop on relativistic and QED effects in heavy and highly

ionized atoms, which we organized in collaboration with H. P. Kelly (University of Virginia) and L. Armstrong (Johns Hopkins University). The

workshop was held at NBS in May of this year and was well attended, with

over 60 participants from 3 continents. Our purpose was to identify the

theoretical problems encountered in treating ul tra-rel ati vi Stic atomic

systems and to establish stronger ties between the diverse theoretical

approaches to computing properties of such systems. While the invited

speakers covered a broad range of topics, the central question centered on the multi-electron aspects of the problem, as we hoped. The extended

discussions were spirited and most participants participated with gusto.

The proceedings will be published in the American Institute of Physics

conference series.

We should note that the workshop served as the curtain raiser on

a series of similar meetings held this past summer: a NATO Advanced Study

Institute held in Corsica in June and a relativistic theory workshop held

in Aspen in August, both with active participation of this group.

A large part of our work this year has been devoted to transferring, upgrading, and debugging programs for the new NBS class VI computer,

the Cyber 205. This has involved a substantial investment of time to

learn, not only the new system, but also the implementation of the vector

capabilities of the machine as well. As of now, all of the atomic physics

codes have been transferred, while the vector upgrading continues to

occupy us.

The comprehensive production codes for computing dielectronic

recombination rates have been used to compute total recombination rates

for ions in the lithium, oxygen, fluorine, neon, and sodium i soel ectroni

c

6
Division 531, Technical Activities (cont'd.)

sequences. These data have been provided to the Impurity Transport Modelling Group at the Princeton Plasma Physics laboratory, where we are con- sulting on a project to model the effects of atomic processes in heavy ion

impurity transport. We are also using these programs in conjunction with

structure codes to compute the detailed, and rich, dielectronic satellite

line spectra of lithium-like ions. Intermediate coupling and configuration interaction are included, and individual wavelengths are estimated by

referring calculated energies to the experimental levels of the parent

lithium-like ion, a procedure which should incorporate most of the

residual relativistic and correlation corrections.

Our studies of shell collapse, in collaboration with the Far UV

Group of Division 533, have concentrated on singly ionized calcium, for

which a comprehensive experiment has recently been completed. These are core-excited states involving a collapsed, or nearly collapsed, 3d electron. Preliminary calculations have included only outer shell correlations, but have clearly identified the low-lying excited states. Quantitative precision, however, is more difficult to obtain, because the shell

collapse magnifies correlation corrections involving the 3p-shell, and

this problem is currently under study.

During the past year, we hosted a number of leading atomic

theorists at NBS. J. J. Desclaux (Grenoble) visited us in May to collaborate on developing computer programs for relativistic continuum wave functions for the Cyber 205 computer. These codes are essential for the calculation of relativistic excitation and ionization cross sections for

heavy, highly stripped ions.

P. M. Mohr (Yale University) spent most of the month of August

here studying the computational aspects of QED-related problems in atomic

structure theory. A beginning has been made for including screening

effects and realistic atomic models in the calculation of the Lamb shift

for multi-electron atoms and ions.

G. Soff (GSI Darmstadt) also visited us in September to apply

theoretical methods developed by Mohr (see above) to superheavy atoms

created by heavy atom colli sons in accelerator experiments.

(b) Data Center- -Si gni ficant progress has been made on the design

and development of computerized databases which will facilitate the

storage, retrieval, and updating of critically evaluated numerical atomic

spectroscopic data. Data elements pertinent to tables of energy levels,

wavelengths, transition probabilities, and lifetimes have been identified

and characteri zed; extensive documentation of requirements and specifications for energy-level tables has been completed, as well as partial

documentation for tables of wavelengths and transition probabilities.

7
Division 531, Technical Activities (cont'd.)

Compilations of atomic transition probability data continued for

the spectra of the Fe-group elements scandium through nickel. Tabulations

of allowed lines of neutral or weakly ionized atoms where the principal

data sources are experimental have been completed, and work on the evaluation and compilation of data on forbidden lines of Fe-group elements is

progressing

.

Two critical reviews of Stark widths and shifts of spectral

lines of both neutral and ionized atoms have been published in the Journal

of Physical and Chemical Reference Data. A spectroscopic data book, which

includes transition probabilities as well as energy levels and wave- lengths, has been completed for the element Fe and has been published as a volume in the new Oak Ridge "Red Book" series on "Atomic Data for Controlled Fusion". Work is now being started on a second volume, which will

contain data for the elements titanium and nickel. A compilation of spectroscopic data on titanium, including energy level diagrams and transition

probability data, was completed in collaboration with several scientists

from major Japanese fusion facilities. Also, we continue to supply in

regular intervals bibliographical reference material for inclusion in the

"International Bulletin on Atomic and Molecular Data for Fusion," which is

published by the International Atomic Energy Agency (IAEA). Our input is

their principal, and often only, source of spectroscopic references.

8
Division 531, Technical Activities (cont'd.)

III. Plasma Radiation Group

(a) Col 1 i sional Rate Coefficients with the 50kJ Theta Pinch- -A side arm port was installed on the theta pinch discharge tube, with the goal to

measure the absol ute excitation rates. However, this made the plasma

unstable and the discharges became i rreproduci bl e . Many attempts were

made to stabilize the discharge to obtain meaningful results but so far

they have met with little success. However, relative excitation rates

for the Ti X ion have already been measured and a publication is in preparation, comparing them with the detailed theoretical calculations of

J. B. Mann of Los Alamos National Laboratory using the distorted wave

method. We found that these Ti X excitation rates measured on the theta

pinch are consistent with the results obtained on the TEXT Tokamak for

copper ions in the same i soel ectroni c sequence. In these measurements the

intensity calibration of the XUV spectrometers contributes the major part

of the overall uncertainty. Lack of a portable VUV standard source for

wavelengths below 600 A for direct intensity comparisons is the main

difficulty. So far, the common practice is to use the branching ratio

technique in situ with the same plasma source generating the specific line

radiation from light ions. However, the current high temperature plasma

sources for fusion and x-ray lasers are unsuitable to produce low temperatures needed for the branching ratios to do an in situ calibration. Thus,

we have been developing the commercially available Samson source as a portable VUV standard for calibrations with the branching ratio technique.

We have successfully tested its stable operation producing the branching

ratio lines in the visible (4619 A) and VUV (209 A) from N V for many

hours. Also, we very recently completed a preliminary calibration of our lm-grazing incidence spectrometer using the NBS SURF II radiometric source

at these wavelengths. We plan to use this spectrometer as a transfer

standard for future comparisons of calibrations.

(b) Tokamak SpectroscopyAnalysis of the n=3 and n=4 magnetic

dipole transition wavelengths have yielded more than 50 new transitions in

the Al-like through Cl - 1 ike ions of Ga through Y. This represents a thorough and systematic study of magnetic dipole transitions utilizing the

TEXT Tokamak National Users Facility. These new measurements will allow

the determination of the radial distributions of Doppler ion temperatures

from a single impurity injection. Investigations of impurity transport in

magnetic fusion devices will benefit from these observations because of

the availability of many wavelengths in the visible spectral region, thus

permitting remote instrument observations with optical fibers during

deuteri um-tri ti urn operation.

Measurements of the absolute emission coefficients of spectral

lines of Al-like and Cl -like Fe, Cu and Zn ions have been accomplished on the TEXT tokamak and analyzed. These observations were obtained using

9
Division 531, Technical Activities (cont'd.)

absolutely calibrated spectrometers in the XUV spectral region based on the branching ratio technique and SURF II. Measurements of the radial

distributions of ion densities combined with these measurements yielded

absolute excitation rates for these spectral lines for the first time on a tokamak

.

(c) Autoionization in Electric Fields- -We have recently observed

autoionizing states in barium having high angular momentum non-penetrating

orbitals. In collaboration with C. Clark of the Radiation Physics Division, we have developed a method to extract electric quadrupole moments

and tensor polarizabilities of the atomic core from the fine structure

splittings contained in our data. This method turns out to be quite

general, and we have also applied it to previously existing data of isoelectronic series of halide-like ions. This has lead to the discovery

that the quadrupole moment of these ions scales inversely with their

charge, i.e.~ l~ l

. This very useful result is not presently understood.

Quadrupole moments for hydrogenic ions scale as Z~2

. One expects a deviation from this for other ions, but an exponent of _1 is surprising

i ndeed

.

The above method, combined with our recently developed theory

for field effects on oscillator strength distribution of resonances in the

continuum, will allow us to compute spectra under the influence of

external electric fields and compare them with our measured spectra.

(d) Calculation of Spectral Line Shapes of Ions in PI asmas --Last

year, in collaboration witn J. Cooper of JILA, we developed a formal

theory for shifts of ion lines in plasmas. Currently we have undertaken a program to actually calculate the shifts and widths of hydrogenic and

alkali-like ions in plasma conditions for x-ray laser experiments. We are doing quite rigorous calculations using close-coupled scattering methods,

and at the same time we are developing "back of the envelope" approximation procedures to be used by the x-ray laser community in the near term.

Line widths play a critical role in laser development, since they affect

the gain exponentially.

(e) Vacuum Ultraviolet Radiometry with Plasmas- -Three calibrations

of the Space telescope Optical Simulator (STOS) were performed in our laboratory for the purpose of calibrating the Faint Object Spectrograph

(FOS) on the Space Telescope. The third calibration of the STOS utilizing

five lamps as irradiance standards was completed early this year. This

calibration covers the wavelength range from 120 to 800 nm. Three of

these sources are low-powered (15W), rf-excited rare gas dimer lamps

developed according to our recommendations. The other two sources are space-qualified Pt-Cr-Ne hollow cathode lamps. The FOS has been calibrated using the STOS and incorporated into the Space Telescope, which

10
Division 531, Technical Activities (cont'd.)

will be deployed in orbit by the Space Shuttle. We are now working on the

calibration of a series of Pt-Cr-Ne and Pt-Ne hollow cathode lamps which

will be used in throughput tests of the instruments on the Space Telescope

as it is being prepared for deployment.

We have also performed further developmental work on VUV radiometric sources and published the results of our studies on a new mono- chromatic source of Lyman-a radiation. This source is valuable in that

spectrally pure radiation can be obtained without the use of a monochromator. Further testing and refinement of the source are necessary for its

establishment as a radiometric standard.

A very successful study of radiation from a 1 aser-produced

heavy-element plasma has been completed. The purpose was to investigate

such a plasma as a far UV source, for use as an irradiance standard and as

a background continuum source for absorption spectroscopy . Quantitative

high-resolution spectra were taken of the radiation from nine target

materials from 7 to 40 nm. Large differences are seen among the various

targets; the data identifies those heavy elements (rare earths, etc.) most

suitable for providing a clean, intense continuum at a given wavelength

region. Measurements were also included on the effects of some parameters, such as laser energy, on the emitted radiation.

(f) Stark Broadening Shifts and Non-hydrogeni c Ion Lines —We have

continued our systematic observations of the Stark broadening of spectral

lines in the homologous sequence of the rare gases and made further

measurements of lines in the first and second ionization stages of Ne, Ar,

Kr, and Xe. We have found i rregul ari ti es in the line widths of spectral

lines within the same multiplet or supermul ti pi et . While this is in

disagreement with some published results, we believe our new data are more

accurate, since they are very reproducible and are consistent over a range

of plasma conditions. We can show that nearby perturbing levels causing

additional broadening of some lines can lead to such i rregul ari ties . We

have also observed the spectral line broadening and shifts in neutral

nitrogen. The electron density of the plasma from these experiments was measured using a He-Ne laser quadrature i nterferometer . The temperature

was measured utilizing the Boltzmann plot of the spectral line intensities

of the ambient 0 II impurity.

We are currently setting up a new experiment for the observation

of the width and shift of lithium-like beryllium lines. Beryllium will be

introduced into the plasma by simply placing beryllium sheets into the

discharge vessel or by laser ablation techniques. This work is a natural

extension of our studies of the width and shift of He II lines.

11
Division 531, Technical Activities (cont'd.)

We have also continued our studies of the asymmetry patterns of

plasma-broadened lines fron neutral atoms, mainly carbon and argon. Since

the asymmetries arise from ion broadening only, their isolation from the

symmetrical Lorentzian profile, which is due to electron broadening,

provides for the first time the opportunity to study both the effects of

ion broadening separately. Quantitative studies of the

the asymmetries—typically only one to three percent of the

line maximum—have provided the first sensitive test of the

theory of ion broadening. We have found that the predicted

line shapes are closely reproduced by the experiment and

electron and

magnitude of

intensity at

quasi-stati

c

theoreti cal

measured and calculated ion broadening parameters are in good agreement.

(g) Rayleigh Scattering and Redistributed FI uorescence- -We have

successfully made a near-resonance Rayleigh scattering measurement on a transient laser-driven barium plasma. The experimental results agree very

well with the theoretical predictions for the regime where all line

broadening except natural broadening is neglected. The plasma density

obtained from the Rayleigh scattering measurement is about 10 13 cm

-3 and

is consistent with an independent absorption measurement. We can also

determine the colli si onal broadening of the plasma by doing Rayleigh scattering within the col 1 i s i onal width of the spectral line and by measuring

the fluorescence caused by collisional redi stri buti on . At the moment, we

are improving the fluorescence detecting system to achieve a better spectral resolution and a better observing geometry. For the near future, we intend to do these measurements at much higher densities (10 15 cm

-3

) for

more prominent collisional effects.

(h) Theory of Plasma Sate! 1 ites —We have developed a theory to

calculate profiles of plasma satellites in turbulent plasmas. This work

is in collaboration with Prof. H.-J. Kunze of the Ruhr University, West

Germany, where a plasma satellite fluorescence experiment is carried out.

Preliminary calculations give very encouraging results for the helium (2P4D, F) plasma satellite structures. Not only do they present a systematic

picture of both plasma satellites (near and far), but they also take care

of the forbidden transition and the second order plasma satellites.

We are now trying to extend the theory to a more generalized

plasma turbulence spectrum for better understanding of the linkage between

the plasma satellites and the plasma wave turbulence.

12
SPONSORED WORKSHOPS, CONFERENCES, AND SYMPOSIA

Division 531, Atomic and Plasma Radiation

Yong-Ki Kim and Andrew Weiss organized an Atomic Theory Workshop on "Relativistic and QED Effects in Heavy Atoms" held at NBS, Gai thersburg

,

on May 23-24, 1985,

13
INVITED TALKS

Division 531, Atomic and Plasma Radiation

Kim, Yong-Ki, "Energy and Angular Distributions of Secondary Electrons,"

Atomic Physics Seminar, University of Pittsburgh, Pittsburgh, Pennsylvania, March 22, 1985.

Reader, J. R., "Wavelengths from a Pt-Ne Hollow Cathode Lamp for Calibration of the High Resolution Spectrograph," Space Telescope Calibration

Workshop, Johns Hopkins University, September 25, 1984.

Roszman, L. J., "Current Research on Dielectronic Recombination at NBS",

Atomic Data Group of the Physics Department of Lawrence Livermore National

Laboratory, February, 1985.

Roszman, L. J., "How Do Plasma Density and Fields Affect Dielectronic

Recombination?", Fifth Topical Conference on Atomic Processes in High

Temperature Plasma, APS, Pacific Grove, California, February 25-28, 1985.

Wiese, W. L., "Atomic Data for High Temperature Plasma," Fifth Topical

Conference on Atomic Processes in High Temperature Plasma, APS, Pacific

Grove, California, February 25-28, 1985.

Wiese, W. L., "Ion Broadening Effects in Plasmas," Fudan University,

Shanghai, Peoples Republic of China, October 29, 1985.

Wiese, W. L., "Laser Applications in Spectroscopy," Joint French-Chi nese Symposium on Applications of Lasers, Shanghai, Peoples Republic of China,

October 31, 1985.

Wiese, W. L., "Foundations of Plasma Spectroscopy," four lectures at Jilin

University, Changchun, Peoples Republic of China, November 2-7, 1984.

Wiese, W. L., "Stark Broadening of Heavy Elements," Kyoto University,

Kyoto, Japan, November 10, 1984.

Wiese, W. L., "Spectroscopic Data and VUV Standards for Magnetic Fusion

Research," U.S. -Japan Seminar on Tokamak Diagnostics by VUV and X-ray

Spectroscopy, Nagoya University, Nagoya, Japan, November 15, 1984.

Wiese, W. L., "Atomic Physics Data for Astronomical Abundance Determinations," Washington Area Astronomers Meeting, Naval Academy, Annapolis,

Maryland, March 21, 1985.

Wiese, W. L., "The NBS Spectroscopic Data Centers," Meeting of the IAEA

Network of Data Centers for Fusion Resarch, Stanford University, July 22,

1985.

14
PUBLICATIONS

Division 531, Atomic and Plasma Radiation

Adelman, Saul J. and Fuhr, Jeffrey R., Optical region elemental abundance

analyses of B and A stars. IV. Re-evaluation with new critically

compiled Fe II oscillator strengths and improved estimates of the damping

constants, Astron. Astrophys. [in press],

Clark, C. W., The discrete 4d photoabsorption spectrum of Ba ++

, J. Opt.

Soc . Am. B

J_, 626 (1984).

Clark, C. W., Isotope Shifts of Some Ultraviolet Transitions of First Row

Elements, Astrophys. J. 285 , 322 (1984).

Cooper, J., Kelleher, D. E., and Lee, R. W., On the Plasma Polarization

Shift in Radiative Properties of Hot Dense Matter : Proceedings of the

Second International Conference, Ed. J. Davis, C. Hooper, R. W. Lee, A.

Mertz and B. Rozsnyai , World Scientific, Singapore (1985), pp . 350-384.

Cromer, C., Bridges, J. M., Lucatorto, T. B., and Roberts, J. R., A HighResolution VUV Spectrometer with Electronic Parallel Spectral Detector,

Proceedings of AIP Conference on Laser Techniques in XUV, 1984, Appl . Opt.

[in press].

Datla, R. U., Measurement of the Ti X ion density in a 0-pinch plasma by a laser heterodyne quadrature interferometer, Phys . Rev. A 3]_, 2764-2767

(1985).

Datla, R. U., Measurement of the Ti X ion density in a 9-pinch plasma by a laser heterodyne quadrature i nterferometer , Abstract, Rev. Sci . Instrum.

56, 1072 ( 1985).

Erickson, R. M., Forman, P. R., Jahoda, F. C. and Roberts, J. R.,

Polarimetric Measurement of Plasma Pol oi dal Magnetic Field via Heterodyne

Phase Shift Methods, IEEE Trans, on Plasma Science, PS-12, 4_ (1984).

Iglesias, L., Kaufman, V., Garcia, Riquelme, 0., Rico, F.R., Analysis of

the Fourth Spectrum of Tungsten (W IV) Phys. Scr. 31_, 173-1 83 (

1 985).

Jones, Douglas W. and Wiese, W. L., Asymmetry patterns of plasma broadened

isolated lines, (C I) Phys. Rev. A _30 » 2602-2608 ( 1984).

Kaufman, V., Sugar, J., van Kleef, Th. A. M., and Joshi , V., Resonance

Transitions 4d 1(J 5s - 4d 9 5s5p in the Ag I Sequence of In III, Sn IV, Sb V,

and Te Vi, J. Opt. Soc. Am. B 2, 426 ( 1985).

15
Division 531, Publications (cont'd.)

Kaufman, V., Iglesias, L., Garcia-Riquelme, 0., and Rico, F. R., Analysis

of the fourth spectrum of tungsten (W IV), Phys. Scr. _31_, 173 ( 1985).

Kelleher, D. E., Ligare, M. and Brewer, L. R., Resonant four-photon

ionization of atomic hydrogen, Phys. Rev. 31 , 2747 ( 1985).

Kelleher, D. E. and Cooper, J., Shifts of Ion Lines in Plasmas, in

Spectral Line Shapes , Vol . 3, F. Rostas, Ed. (Walter de Gruyter & Co.,

Berlin, 1985) p. 85.

Kelleher, D. E., Delpech, J. F., Weiner, J. and Clark, C. W., Broadening

of a Valence Autoionization Resonance in Electric Fields, in Spectral Line

Shapes , Vol. 3, F. Rostas, Ed. (Walter de Gruyter & Co., Berlin, 1985)

p . 39

.

Kelleher, D. E., Ligare, M. and Brewer, L. R., Resonant Multiphoton

Ionization of Atomic Hydrogen, in Spectral Line Shapes , Vol. 3, F. Rostas, Ed. (Walter de Gruyter & Co., Berlin, 1 985) p . 347.

Kelleher, D. E., Delpech, J. R., and Weiner, J., Broadening of a valence

autoionization resonance in electric fields, Phys. Rev. A 32 ( 1985)

.

Kim, Y.-K., Martin, W. C., Weiss, A. W., Relativistic and Correlation

Effects in the 2s3p Configuration of Be-like Ions, Proc. of Ninth

International Conference on Atomic Physics (1985).

Klose, J. Z., Bridges, J. M., and Ott, W. R., Monochromatic source of

Lyman-a radiation, Appl . Opt. _24, 2263-2266 ( 1985).

Konjevit, N., Dimitri jevit, M. S., and Wiese, W. L., Experimental

Stark Widths and Shifts for Spectral Lines of Neutral Atoms (A Critical

Review of Selected Data for the Period 1976 to 1982), J. Phys. Chem. Ref.

Data 13_, 619 ( 1984).

Konjevit, N., Dimi tri jevit, M. S., and Wiese, W. L., Experimental

Stark Widths and Shifts for Spectral Lines of Positive Ions (A Critical

Review and Tabulation of Selected Data for the Period 1976 to 1982), J.

Phys. Chem. Ref. Data _13_, 649 (1984).

Lombardi, G. G., Kelleher, D. E., and Cooper, J., Redistribution of

Radiation in the Absence of Collisions, Astrophys. J. 288, 820 (1985).

Martin, G. A., Fuhr, J. R., and Wiese, W. L., Critical Compilations of

Atomic Transition Probabilities, Proceedings of 8th International

Colloquium on Ultraviolet and X-ray Spectroscopy of Astrophysi cal and

Laboratory Plasmas, NRL (19 84).

16
Division 531, Publications (cont'd.)

Martin, W, C., Zalubas, R., and Musgrove, A., Energy Levels of Phosphorus,

P I through P XV, J. Phys. Chem. Ref. Data _1_4, 3 ( 1985).

Martin, W. C., Structure of Atomic Spectra, Trans. Intern. Astron. Union,

1985 [in press]

.

Mori, K., Wiese, W. L., Shirai, T., Nakai , Y., Ozawa, K. and Kato, T.,

Spectral Data and Grotrian Diagrams for Highly Ionzied Titanium, Ti VTi XXII, Atomic Data and Nuclear Data Tables 33_ ( 1985).

Musgrove, A. and Zalubas, R., Bibliography on Atomic Energy Levels and

Spectra, July 1979 through December 1983, Nat. Bur. Stand. (U.S.) Spec.

Publ . 363, Suppl . 3, June 1 985.

Nee, T. A., Near-resonance-Rayl ei gh scattering measurement on a resonant

laser-driven barium plasma, J. Appl . Phys. _57_, 4968-4972 ( 1985).

Reader, J., Ryabtsev, A. N., and Ramonas, A. A., Resonance transitions of

Kr X, J. Opt. Soc. Am. B 2, 417-429 (1985).

Rudd, M. E., Kim, Y.-K., Madison, D. H., and Gallagher, J. W., Electron

Production in Proton Collisions: Total Cross Sections [in press],

Sansonetti, C. J. and Lorenzen, C.-J., Doppler-free resonantly enhanced

two-photon spectroscopy of np and nf Rydberg states in atomic cesium,

Phys. Rev. A 30, 1 805-1 811 ( 1984).

Saloman, E. B., Cooper, J. W. and Kelleher, D. E., El ectric- Fi el d- Induced

Interferences in Autoionizing Resonances, Phys. Rev. Lett . _55 , 193

(1985).

Saloman, E. B., Cooper, J. W., and Kelleher, D. E., Studies of Electric

Field Effects and Barium Autoionizing Resonances, in Atomic Excitation and

Recombination in External Fields , M. H. Nayfeh and C. W. Clark, Eds.

(Gordon and Breach, New York, 1985), pp. 32 5-326.

Smith, E. W., Stamm, R. and Cooper, J., Discussion of the conditionalprobability function for electric fields in a plasma, Phys. Rev. A 30

,

454-467 ( 1984).

Stamm, R., Smith, E. W., and Talin, B., Study of hydrogen Stark profiles

by means of computer simulation, Phys. Rev. A, 2039-2046 (1984).

Stamm, R. and Smith, E. W., Computer simulation technique for plasmas,

Phys. Rev. A 30, 450-453 (1984).

17
Division 531, Publications (cont'd.)

Sugar, J. and Corliss, C., Energy Levels of the Elements of the Iron

Period, Potassium through Nickel, J, Phys. Chem. Ref. Data [in press].

Sugar, -J., Kaindl, G., and Brewer, W., Photoabsorption by the 3d shell in

CeF3

, PrF3

, and HoF3

: Observations and Calculations [in press],

Wang, J. S., Marotta, A. and Datla, R. U., Col 1 isional Excitation Rate

Coefficients for Fe XI, Astrophys. J. 279 , 460-462, April 1984.

Wiese, W. L., ed. Spectroscopic Data for Iron, Vol . IV of Atomic Data for

Controlled Fusion Research , 0RNL-6089 (1985).

Wiese, W. L., Atomic Transition Probabilities in Reports on Astronomy

(Reidel Publ . Co., Holland, 1985) Transact, of the Intern. Astron. Union,

Vol . XIX.

Wiese, W. L., Experimental Methods for Determining Atomic Transition

Probabilities, in The Physics of Ionized Gases , Proc. XII SPIG 1984 [in

press]

.

18
PUBLICATIONS IN PREPARATION

Division 531, Atomic and Plasma Radiation

Brewer, L. R., Ligare, M. and Kelleher, D. E., Four Photon Resonance

Enhanced Ionization of Atomic Hydrogen and Threshold (in preparation)

.

Clark, Charles W., and Kelleher, D. E., Quadrupole Moments and Tensor

Polarizabilities from Fine Structure Splittings of Non-Penetrating

Orbitals (in preparation).

Clark, Charles W., Isotope Shifts of Some Ultraviolet Transitions of First

Row Elements (in preparation).

Cooke, W. E. and Cromer, C. L., Multichannel Quantum Defect Theory and an Equivalent N Level System (in preparation).

Cromer, C. L. and Clark, C. W., Resonant Structure in Multiphoton Ionization of Calcium (in preparation).

Gohil, P., Kaufman, V., and Mcllrath, T. J., High Resolution Spectra of

Laser Plasma Light Sources in the Grazing Incidence Region (in preparati on )

.

Jones, D. W., Wiese, W. L., and Woltz, L. A., Ion broadening of Ar I lines

in a plasma (in preparati on )

.

Kaufman, V. and Sugar, J., Forbidden Lines in the ns

2 np

k Ground Configurations and nsnp Excited Configurations of Be through Mo Atoms and Ions (in

preparation)

.

Kelleher, D. E., Saloman, E. B., and Cooper, J. R., The Effect of Electric

Fields on Autoionizing Resonances, Proc. of the 7th Inti. Conf. on Laser

Spectroscopy, 1985 (submitted).

Kim, Y.-K., Martin, W. C., and Weiss, A. W., Relativistic and Correlation

Effects in the 2s3p Configuration of Beryllium-like Ions (in

preparation)

.

Konjevid, N. and Pittman, T., Stark broadening of spectral lines of

homologous, doubly ionized inert gases, J. Quant. Spectrosc. Radiat.

Transfer (submitted).

Mcllrath, T. J., Sugar, J., Kaufman, V., Cooper, D., and Hill, W. T., Ill,

Laser-driven ionization of Cs and absorption spectrum of resultant Cs + vapor (submitted).

19
Division 531, Publications in Preparation (cont'd.)

Mishin, V. I., Lombardi, G., and Kelleher, D. E., Electric Field Effects

in Autoionizing States in Gadolinium (submitted).

Nee, T. A., Calculation of Helium Plasma Satellites in Turbulent Plasmas

( i n preparation)

.

Persson, W. and Reader, J., Wavelengths and energy levels of Y VI (in

preparation)

.

Pittman, T. L. and Konjevit, N., Experimental Study of Stark Broadened

N II Lines from States of High Orbital Angular Momentum (in preparati on) .

Pittman, T. L. and Konjevit, N., Stark Broadening of Singly Ionized Neon

Lines (submitted).

Pittman, T. L. and Konjevit, N., Stark Broadening along Homologous

Sequences of Singly Ionized Noble Gases, J. Quant. Spectrosc. Radiat.

Transfer (submitted).

Pittman, T. L. and Fleurier, C., Plasma Shifts of the He II Ha and Pa Lines. Phys. Rev. A (submitted).

Reader, J., Spectrum and energy levels of the sodiumlike ion Sr27+ (in

preparati on ) .

Reader, J. and Sansonetti , C. J., Accurate determination of the energies

of low-lying levels of singly ionized Hgi98 (in preparation)

.

Reader, J., Acquista, N., and Goldsmith, S., Energy levels of the terms

4s 2 4p

2 P°, 4s4p2 2 P, and 4s 2 5s 2 S in the galliumlike ions Rb VII - In XIX

(in preparation).

Roszman, L. J., The dielectronic recombination rates for some ions of the

lithium isoel ectronic sequence (in preparation).

Saloman, E. B., Cooper, J. W., and Kelleher, D. E., Studies of field

effects on barium autoionizing resonances, Phys. Rev. Lett, (submitted).

Sansonetti, Craig J. and Andrew, Kenneth L., The Spectrum and Energy

Levels of Singly Ionized Cesium: I. Revision and Extension of the Cs II Energy Levels (submitted).

Sansonetti, C. J. and Weber, K.-H., Precise measurements of Doppler-free

two-photon transitions in Rb: A reevaluation of suggested dye laser

reference wavelengths (in preparation )

.

20
Division 531, Publications in Preparation (cont'd.)

Sugar, J. and Kaufman, V., Copper Spectra in a Laser-Generated Plasma:

Measurements and Classifications of Cu XII to Cu XXI (in preparation).

Tech, J. L., Observatory Reports, Bull. Am. Astron. Soc. (in

preparati on )

.

Tech, J. L., The spectrum of singly-ionized bromine ( Br II) in the vacuum ultraviolet (in preparation)

.

Weber, J.-H. and Sansonetti, C. J., Precise measurements of cesium ns, np,

nd, nf and ng Rydberg state energies (in preparati on ) .

Weiss, A. W., On local exchange approximations, Phys. Rev. - Brief Reports

( i n preparati on ) .

Woltz, L. A., Quasi-Static Ion Broadening of Isolated Spectral Lines (in

preparati on )

.

21
TECHNICAL AND PROFESSIONAL COMMITTEE PARTICIPATION AND LEADERSHIP

Division 531, Atomic and Plasma Radiation Division

Daniel E. Kelleher

Member, International Organizing Committee of the Conference on Spectral Line Shapes.

Yong-Ki Kim

Member of Program Committee, APS Topical Conference on High

Temperature Plasmas.

Georgia Martin

Chairperson, NAS/NRC Committee on Line Spectra of the Elements - Atomic Spectroscopy.

William C. Martin

Chairman, Working Group on Structure of Atomic Spectra, International

Astronomical Union.

Member, IAEA Network of Atomic Data Centers for Fusion.

James R. Roberts

Member of TEXT Users Organization.

Jack Sugar

Member, OSA Meggers Award Committee.

Member, NAS/NRC Committee on Line Spectra of the Elements - Atomic

Spectroscopy

.

Wolfgang L. Wiese

Member of Organizing Committee, International Astronomical Union,

Commision on Fundamental Spectroscopic Data.

Chairman, Working Group on Atomic Transition Probabilities, International

Astronomical Union, Commission 14.

Member, IAEA network of Atomic Data Centers for Fusion.

22
Division 531, Technical and Professional Committee Participation and

Leadership (cont'd.)

Wolfgang L. Wiese

Member, OSA Meggers Award Committee.

Co-Chairman, US-Japan Workshop on "Tokamak Diagnostics by Visible,

VUV and X-ray Radiation," Nagoya, Japan.

23
MAJOR CONSULTING AND ADVISORY SERVICES

Division 531, Atomic and Plasma Radiation

1. The Data Centers on Atomic Energy Levels and Transition Probabilities

routinely fill requests for atomic data or literature information

submitted by scientists in a wide range of research areas. The

requests average about 30 per month. On occasion, special reports

are prepared for particular user groups. Thus, W. C. Martin and

W. L. Wiese write updates on atomic data of interest for the astrophysical community for the IAU Transactions, and give review reports

at the General Assemblies of the International Astronomical Union.

2. J. M. Bridges has consulted with staff of Ball Aerospace, Boulder,

CO, concerning use of standard sources in calibration of instruments

for UV measurements in space.

3. Y.-K. Kim serves as a consultant to the A Division of the Lawrence

Livermore Laboratory on x-ray laser development.

4. Kim has also consulted with the Princeton Plasma Physics Laboratory

on the role of atomic processes in plasma cooling. This led to a reassessment of the role of neutral hydrogen atoms in fusion reactors

being designed under the INTOR program.

5. J. Z. Klose performed numerous tests and calibrations of three Pt-Ne

and two Pt-Cr-Ne hollow cathode lamps this year as part of contract

work with Martin Marietta Aerospace. His work involved close consultation with Martin Marietta personnel concerning the results of each

test and plans for successive tests and calibrations.

6. W. C. Martin and J. Reader have consulted and advised NASA scientists

and other astronomers on standard wavelengths for calibration of the

High-Resolution Spectrograph for the Space Telescope, and Reader has

also advised on and assisted with tests of the large echelle grating

for this instrument.

7. J. R. Roberts serves as a member of the TEXT Users Organization

(TUO). TEXT stands for Texas Experimental Tokamak and is a national

plasma users facility. The TUO steering committee considers the

special needs of off-site user groups and has provided advice and

perspective on the users program to the TEXT managers and the Office

of Fusion Energy at DOE.

8. L. J. Roszman provided consulting activities on various electron-ion

collision processes and high density plasma modeling for x-ray laser

24
Division 531, Major Consulting and Advisory Services (cont'd.)

research and development in the Lawrence Livermore National Laboratory A and Physics Divisions.

9. L. J. Roszman advises and consults with the Impurity Transport Modeling Group of the Princeton Physics Laboratory on electron-ion collision processes and other atomic data as well as the modeling of low

density plasmas.

25
JOURNAL EDITORSHIPS

Division 531, Atomic and Plasma Radiation

J. Reader, Editor, Line Spectra of the Elements, Handbook of Chemistry and

Physics , CRC Press.

"

W. L. Wiese, Associate Editor, Journal of Quantitative Spectroscopy and

Radiation Transfer.

26
TRIPS SPONSORED BY OTHERS

Division 531, Atomic and Plasma Radiation

Y.-K. Kim traveled to the University of Pittsburgh, Pittsburgh,

Pennsylvania for discussions with their atomic physics group and to give

an invited talk. The trip was paid for by the University of Pittsburgh

( March 1985) .

L. J. Roszman traveled twice to the Lawrence Livermore Laboratories in

California as a consultant with an R-Program group led by Dr. S. Younger.

Both trips were paid for by LLNL (February, July 1985).

L. J. Roszman traveled twice to the Princeton Plasma Physics Laboratory as

a consultant. Both trips were paid for by PPPL (June, July 1985).

T. A. Nee spent three months at the Institut ftir Experimental physi k V,

Ruhr University Bochum, West Germany, to attend their plasma diagnostics

programs. Most of the expenses were paid by the Sonderforschungsbereich

Plasmaphysik Bochum/ Jill ich (October-December 1984).

W. L. Wiese gave several invited talks and lectures at Fudan University,

Shanghai and Jilin University, Changchun during the period October 28-

November 8, 1984. All expenses in China were paid by the Chinese host

organizations

.

W. L. Wiese traveled to Dubrovnik, Bel grade, . and Zagreb, Yugoslavia. He

attended the Boris Kidric Institute seminar in Belgrade and reviewed

ongoing projects under the NBS-Yugoslav Cooperative S&T Program at

Belgrade University and Institute of Zagreb. Airfare was paid by the USYugoslav Joint Board (June 1985).

27
CALIBRATION SERVICES PERFORMED

Division 531, Atomic and Plasma Radiation

No. of

Type of Service Customer SP 250 Tests Income

Hollow Cathode

Lamp

Martin Marietta Contract 10 $ 37 k

Argon Arc NOAA Contract 1 2k

Argon Arc EG & G 7 .6

B

1 1 ,8k

Argon Arc Physical Res. Lab.

Ahmedabad, India

7.6C 1 1 .8k

Argon Arc Changchun Inst, of

Optics, China

7.6C 1 1 .8k

Deuterium Lamp General Electric 7.6D 1 Ik

Deuterium Lamp Aerojet Electrosystems 7.6D 1 0.6k

28
SPONSORED SEMINARS AND COLLOQUIA

Division 531, Atomic and Plasma Radiation

Byron A. Palmer, Los Alamos National Laboratory, "The Los Alamos HighResolution Fourier Transform Spectrometer", October 5, 1984,

Thomas Gallagher, University of Virginia, "Laser Spectroscopy of

Autoionizing Rydberg States", March 14, 1985.

K. T, Lu, Atomic and Plasma Radiation Division, "The Fermi -Segfe Formula

Revisited: On the Study of the Ion-Core by Rydberg Electrons",

April 17, 1985.

Nikola Konjevit, Institute of Physics, Beograd Yugoslavia, "Stark

Broadening of Helium Lines in a Dense Cool Plasma", April 24, 1985.

Chris Cromer, Atomic and Plasma Radiation Division, "A New, Intuitive

Approach to MQDT" , May 15, 1985.

Rene Beigang, Free University of Berlin, "High Resolution Laser

Spectroscopy of Rydberg States with Principal Quantum Numbers N > 100",

May 22, 1985.

Alexander Piel, Institut fur Experimentalphysik, Ruhr University, Bochum,

West Germany, "Ion Dynamic Effects for Plasma Broadened Helium Lines",

May 31 ,1 985.

Alfred Muller, JILA and University of Giessen, West Germany, "ElectronImpact Ionization of Ions with Comments on Recent Dielectronic

Recombination Experiment at JILA", July 1, 1985.

29

TECHNICAL ACTIVITIES

Division 533, Radiation Physics

Task No. 15233 - Far UV Radiometry

Task No. 15234 - Far UV Measurements

Task No. 15235 - Electron Physics Research

The Radiation Physics Division focuses on measurement programs

relating to the use of electron, laser, ultraviolet, and soft x-ray

radiation in the energy range from about 5 eV (250 nm) to 300 eV (4 nm).

In support of this mission, radiation standards and advanced

measurement techniques are developed. Through our standards program, the

Division provides the central national basis for the measurement of far

ultraviolet and soft x-ray radiation. The NBS synchrotron radiation

facility and a detector calibration facility based upon wel 1 -characterized

photoionization chambers serve as national radiation standards.

Measurement services are available for the calibration of the quantum

efficiency of UV photodiodes and the spectral responsivity of vacuum ultraviolet spectrometer systems.

Through our electron measurements program, new types of electron

sources and detectors are developed to investigate the properties of

matter on an atomic scale. For example, specially designed spin-polarized

electron sources and detectors are used to determine fundamental atomic

scattering properties and to measure surface magnetism. An electron

tunneling device is being developed to provide "images" of surfaces on an atomic scale and to study relationships between macroscopic material

properties and surface microstructure.

With the goals of improving standards and understanding the

fundamental physical phenomena upon which they are based, the Division

also conducts theoretical and experimental research on the electronic

structure of atomic and molecular systems, the interaction of the systems

with photon and electrons, and radiation deposition and energy transfer

processes. Theories are developed for the scattering and transport of

electrons in materials of fundamental and technological interest. New

techniques and instrumentation are developed to study radiative reactions

with matter, including photoexcitation and photoionization processes and

non-linear effects in intense laser fields. Studies are underway to

investigate to what extent the properties and behavior of atomic systems

31
Division 533, Technical Activities (cont'd)

can be manipulated by measuring and controlling atomic and molecular

states in their local environment.

The division has two major research facilities, a dedicated

synchrotron ultraviolet radiaton facility (SURF II) and a polarized

electron research facility.

SURF II is a dedicated synchrotron radiation facility, consisting of

a 280 MeV electron storage ring, a 10 MeV microtron injector, and

associated synchrotron radiation beam lines. It produces light in a narrow, intense, highly polarized beam with a continuous and accurately

known spectrum from the infrared through the visible and into the far

ultraviolet. SURF II is unique among synchrotron light sources by virtue

of its uniform and precisely known circular orbit. This allows accurate

determination of all the spectral and geometrical properties of the

radiation and hence its use as an absolute radiometric standard.

This facility serves staff from our own division, users from other

NBS divisions, and outside users in radiometric standards and calibration

work, optical physics research, surface science, biochemistry,

spectroscopy, and other research areas utilizing far ultraviolet

radiation. It fills a growing demand for radiation in the ultraviolet

and soft x-ray region of the electromagnetic spectrum. Of the 11 light

ports at SURF, 6 are now instrumented for user applications and for

calibration of optical instruments and transfer standard photodiodes.

Some of these ports are shared by more than one experimental station.

Three of the remaining ports are utilized for beam current monitoring,

electron counting, and machine diagnostics. Most experiments and

calibrations can run simultaneously, unless they require special beam

parameters.

The polarized electron scattering facility is used to produce and

measure beams of spin polarized electrons and is available for

collaborative research by NBS and outside scientists in areas of mutual

interest on a time-available basis. Three separate, ultra-high vacuum instruments are available. The polarized electron beams have currents in excess of 1 uA, with an optically reversible polarization at energies less

than 1 KeV and with an energy resolution of »0.15 eV.

These electrons are used to probe spin dependent scattering

interactions between polarized electrons and surfaces or polarized

electrons and atoms. The electron-surface scattering capability can be

used to determine surface structure or study surface magnetic phenomena

and their dependence on temperature, composition, adsorption, etc. The

electron-atom scattering capability can be used to probe spin-orbit and

exchange interactions in electron scattering and to completely determine

the parameters of a selected collision process. In a new research

32
Division 533, Technical Activities (cont'd)

direction, special electron spin detectors can be used in combi nation w it

h

a scanning electron microscope to constitute an electron polarization

microscope that can probe magnetic structure on a sub-micron scale.

As can be seen in the following sections, the division staff has been

active in publishing research papers, providing calibration services,

presenting invited talks, sponsoring conferences, providing consultation

services, and participating in technical and professional committees. We

have also been very active in technical collaborations within NBS and with

universities, industry, and other government agencies. Highlights of the

past year include:

1. A fundamental theory was developed to explain the spinpolarization of secondary electrons emitted from magnetic

materials, a phenomenon first measured here and now being

exploited by us to enable measurements of surface magnetism and

magnetic microstructure.

2. A spin-polarized, scanning electron microscope has been

demonstrated by modifying a UHV-SEM with a newly developed

pol arized-el ectron detector system. Initial measurements were

made of an Fe 97 Si

3 crystal with magnifications of x500 to

xl0,000 and showed that both physical and magnetic

microstructure could be simultaneously measured.

3. An enhanced program on Scanning Electron Microscopy with

Polarized Electron Analysis (SEMPA) was planned with the

assistance and support of the Director's office. Elements of

the plan include: (1) public information announcements; (2) a briefing to the NBS Visiting Committee; (3) an assessment of

industrial needs for measurements of magnetic microstructure;

(4) purchase of a new UHV-SEM; and (5) soliciting funding

support and cooperative research with industry.

4. Fundamental measurements that are stimulating a new area of

theoretical and experimental atomic collisions research were

made in a series of polarized electron-pol arized atom, stateselected scattering experiments. For the first time, electron

exchange effects were directly measured in super-elastic

electron-atom scattering.

5. A workshop on "Atomic Spectra and Collisons in External Fields"

was held at NBS on October 22 and 23. It attracted about 88

participants. Its purpose was to discuss recent work on highly

excited atoms in electric and magnetic fields.

33
Division 533, Technical Activities (cont'd)

6. A new data evaluation project on Soft X-Ray Interactions with

Matter was funded by SRD and DOE and initiated in collaboration

with the Ionizing Radiation Division.

7. A new record stored beam current of 200 mA at full operating

energy of 284 MeV was achieved at SURF, almost twice as much as last year's record current and about 20 times higher than the

design level.

8. Major new areas of research activity were started at SURF:

- new high flux surface science beam line was constructed.

- new soft x-ray fluorescence experiment is on-line, in

collaboration with U. of Tennessee and ORNL.

- new photoionization experiment utilizing fluorescence

spectroscopy is on-line.

- new beam line has been built up for extremely high resolution

atomic and molecular spectroscopy, in col 1 aboration with U. of

Maryland and NRL and with the support of NSF.

- new detector calibration beam line is in operation.

- first results were obtained from the new high resolution

photoelectron spectrometry facility (ARPES).

9. A major, new radiometric intercomparison of SURF and standard

lamps was successfully carried out in the near ultraviolet

-through an industrial research associate arrangement with

H. Kostkowski, assisted by a visiting scientist from NOAA and

staff from divisions 531, 533, and 534.

10.

A new collaboration between the Far UV Physics staff and staff

from LANL was planned to enable complementary and coordinated

photoionization studies to be done at Brookhaven/NSLS and

NBS/SURF

.

11 . A plan was presented by

obtaining funding for a of other agencies, viz,

sufficient capabilities

user's facil ity.

R. Madden to the Director's office for

SURF upgrade from NBS and a consortium

DOE and NSF. The goal is to provide

for SURF to be a national synchrotron

34
Division 533, Technical Activities (cont'd)

12. For the second year in a row, work in the Division is being

recognized with an I R— 100 award (Celotta, Pierce, Feigerle, and

Seiler: A New High Current Monoenergetic Electron Gun).

FAR UV PHYSICS GROUP

The Far UV Physics Group is characterized by the development of

radiometric techniques and standards for far ultraviolet radiation and by

research on measurement methods utilizing far ultraviolet radiation. Use

is made of the NBS synchrotron ultraviolet radiation facility (SURF II),

as well as other synchrotron radiation facilities (Orsay, Brookhaven), to

investigate the fundamental interactions of photons with atoms and

molecules and to establish a basis for radiometric standards and

spectrometer sensitivity measurements in the far ultraviolet.

Additionally, off-SURF experimental and theoretical research is carried

out to study multiphoton effects in laser-excited and laser-ionized

materials, and to investigate fundamental fragmentation processes in

organic molecules.

SURF Operations and Improvements

SURF II performance took another quantum leap upward this year when a record beam current of 2U0 mA was achieved on June 4, 1985. This current

was nearly double the 103 mA record of June 13, 1984. In fact, stored

beam currents exceeding 100 mA were routinely achieved from April through

July 1985. This improvement was due to a new, commercially-developed

cathode utilizing oriented single-crystal lanthanium hexaboride as the

emitter. Such cathodes were first made for scanning electron microscopes,

but this is the first known application in an accelerator. The microtron

injector is now performing very near its design limit, routinely

delivering 60 mA at 10 MeV, nearly double the peak currents obtained in

the past with polycrystalline LaB 6 cathodes. The commerical cathodes also

exhibit excellent long-term stability and longevity, resulting in higher

average beam intensities and reduced downtime.

The usefulness of the high stored currents has been limited by rather

poor beam lifetime at 280 MeV. This is because the 2 kW RF power supply,

originally designed for 240 MeV, is marginal at the higher energy. A new

5 kW system is now being commissioned. It should not only improve

substantially the beam lifetime at 280 MeV, but have enough reserve

capacity to allow operation up to 300 MeV.

In preparation for the new RF system, the old RF output cable was

replaced with a low-loss coaxial transmission line. This change alone

resulted in 10% higher cavity voltage and a noticeable improvement in beam

lifetime at 280 MeV. A second effect of the low-loss line appears to be

35
Division 533, Technical Activities (cont'd)

stronger interaction between the stored beam and the amplifier output

impedance. Longitudinal bunch oscillations are now more violent than

before, especially at lower energies while ramping. As expected, this

interaction also depends on line length and is strongest when the line is near an integral number of half-wavelengths long. We have recently been

able to raise the threshold of the longitudinal oscillations from 19 mA to

over 90 mA by trimming the line length. The stabilized beam exhibits much

better lifetime than an oscillating one. We are now studying the contributions to beam lifetime and stability of: (a) transmission line length;

(b) line attenuation; (c) cavity voltage; and (d) amplifier impedance.

Further study is needed to determine if proper tuning of these

elements can passively stabilize beam currents of 200 mA or more, over the

full energy range from 10 to 300 MeV. An electronic phase shifter of

suitable frequency and bandwidth is also available to try stabilization by

phase feedback. If the bunch oscillations can be controlled, stacking of

multiple injections may still be possible. In that case the upper limit

for SURF beam intensity may be even higher than the present maximum of 200

mA.

It has also become clear that modification of bunch length (to

improve beam lifetime) by the use of a higher harmonic RF cavity will not

be successful unless the beam is first stabilized. Work on the harmonic

RF system has therefore been temporarily sidelined until the stability

problem is solved.

In the course of studying the oscillations, SURF operations staff

made a significant contribution to the understanding of a class of beam

instabilities in storage rings, referred to in the 1 iterature as "slow

fluctuation". This type of instability was shown to be a relaxation

oscillation in which intervals of longitudinal oscillation alternate with

(usually) longer, oscillation-free intervals. The oscillation in SURF is

simple dipole-mode (rigid bunch) phase oscillation which grows in amplitude until non-linear restoring forces introduce sufficient frequency

spread among particles that coherence is lost and oscillation closes. The

oscillation-free interval is dominated by radiation damping, so its

duration is strongly energy -dependent . A simple phase modulation model of

the dipole-mode oscillation was adapted from communication theory. This

model accurately predicts the strengths of the RF harmonics and modulation

sidebands observed on the beam current by a spectrum analyzer. It also

predicts a negative feedback mechanism that may help explain the observed

stabilization and self-limiting of oscillations. These studies were

reported at the 1985 Particle Accelerator Conference.

36
Division 533, Technical Activities (cont'd)

New High Energy Capability at SURF

The success of our programs utilizing the high-flux normal -i nci dene

e

monochromator has led us to proceed with the extension of our capabilities

to shorter wavelengths. We have installed a new high-throughput grazingincidence monochromator for SURF-II. This instrument uses SURF's orbiting

electron beam as its entrance slit —thus taking advantage of SURF's small

vertical beam size and high brightness. The grating is placed as close as possible to the orbit and intercepts 51 mrad of horizontal orbit and (for

wavelengths below 500A) the full vertical radiation output. Using three

independently optimized gratings, the monochromator will cover the 30-

600 A spectral range. The first grating has been characterized and

provides ~10 l0 photons per second per mill i amp of ring current at the peak

of its intensity curve. With a typical 100 ma stored current, ~10 i2

photons per second are delivered to the sample. Larger exit slits can increase this by a factor of 4 with some decrease in resolution. The

range of the present grating is 17 to 90 eV.

The new monochromator will allow us to extend our programs in surface

science, ultraviolet photoemission spectroscopy, and gas-phase angleresolved photoelectron spectroscopy to higher photon energies. Two stages

of differential pumping are provided between the experimental chamber and

the monochromator so that gas phase experiments should be able to operate

with relatively high source pressures. Additional gratings are being

manufactured which will reduce 2nd order light and extend the range to

~180 eV photon energy.

Angle-Resolved Photoelectron Spectroscopy

A long successful run at SURF has been completed utilizing our high

resolution angle-resolved photoelectron spectrometer. This run stretched

over a 14-month period during which studies on N

2 , H2 , C0 2 , and NO were

completed. These studies utilized the angle-resolved capability of the

photoelectron spectrometer system to elucidate the mechanism of resonance

processes in molecular photoionization. The resonance processes, autoionization and shape resonances, play a central role in photoionization of

valence shell electrons. This study therefore affords a window into the

mechanisms of electron correlation in molecules.

The two spectrometers of the instrument are now being outfitted with

multichannel array, position-sensitive detectors. These devices, along

with appropriate software improvements, will provide at least a factor of

ten improvement in electron signal with a corresponding gain in the basic

sensitivity of the instrument. These improvements will permit new and

novel experimental programs.

37
Division 533, Technical Activities (cont'd)

This program is a collaboration between NBS and staff at Argonne

National Laboratory and Los Alamos National Laboratory.

Polarized Fluorescence Studies

A series of studies has been carried out at SURF using the

polarization of the synchrotron radiation beam as a probe of molecular

autoionization. These studies showed that the polarization of the

fluorescence from excited states is a direct probe of the photoionization

dynamics and of the symmetry signatures of autoionization resonances. The

modification of the original apparatus has been completed. A new optical

bench has been constructed to more fully exploit the high flux

capabil ities at SURF.

We now have the capabilities to do the following:

(a) study polarized fluorescence from molecular gases;

(b) study wavelength-dispersed fluorescence from molecular systems - the high brightness of SURF is especially important for these

measurements

;

(c) study threshold shifts induced by external electric fields at

photon energies above the ionization threshold.

First measurements with the new apparatus at SURF are in progress. We are concentrating on oxygen. The study of shape resonance effects in water

vapor are also planned for the current running time at SURF. In collaboration with staff from Howard University, we are seeking support

for experiments to derive the heat of formation of important atmospheric

species by observing the fluorescence of dissociative products.

Soft X-Ray Spectroscopy Using Synchrotron Light Excitation

This program is a study, by means of soft x-ray emission spectroscopy,

of fragile compounds that are easily damaged by electron beam irradiation.

The construction of the high sensitivity soft x-ray spectrometer is being

funded by an NSF grant to the University of Tennessee. The spectrometer

was finished during the summer. After initial testing at the University

of Tennessee, the hardware was installed at SURF-II for an extended run. First results on the silicon L

2 3 emission band were obtained at SURF, in

collaboration with the Semiconductor Materials and Processes Division. We

expect to move the gear to Brookhaven National Laboratory during the

winter of 1985. Initial work there will be to study the emission spectra

of systems of interest to material scientists. We are proposing to study

boundaries and interfaces in silicon compounds and other systems of

38
Division 533, Technical Activities (cont'd)

importance in the fabrication of semiconductor devices. Another area that

we are proposing to investigate is the emission spectra of the solid inert

gases, their alloys, and impurities embedded in the rare gas matrix. This

program is a collaboration between the University of Tennessee, Oak Ridge

National Laboratory, and NBS.

Laser Prepared States

A new class of experiments is being planned for SURF which will

utilize both lasers and synchrotron radiation. We have purchased an argon-ion pump laser and now are requesting funds to purchase the broadly

tunable ring dye laser. The new hardware for the polarized fluorescence

experiment will be adaptable to these experiments as will be the high

resolution photoelectron spectrometer.

In the interim it has been possible to continue a collaborative

research program at LURE in Orsay, France. This experiment consists of a toroidal grating monochromator connected to the ACO storage ring at LURE,

and a ring dye laser stabilized to 20 MHz bancton'dth and used to pump

ground state atoms to excited states in the atomic vapor. The output of

the monochromator and the laser intersect at right angles in the sensitive

volume of the electron spectrometer. An effusive beam of metal vapor

intersects these photon beams and the photoelectrons produced in the

interaction zone are detected in the electron energy analyzer.

This year we have been able to accomplish several major goals:

a) We have measured the oscillator strength of autoionizing

resonances in sodium produced by transitions of the type 2p 6 3p>

2p 5 (2p 3/2 , i/2 )3s3p( i »^P). A letter describing these results has

been accepted for publication.

b) We have measured the partial photoionization cross section of the

5d electron in laser-excited barium vapor over a broad energy

range (18 eV to 150 eV). Autoionizing structure involving the

excitation of a 5p electron in the presence of an outer electron

excited to a 5d orbital has also been observed for the first

time.

c) A book chapter is being prepared for Advances in Atomic Physics , reviewing photoionization from excited atoms.

In addition to scientists from SURF and LURE, researchers from the

Laboratoire Aime Cotton, the Service de Physique des Atoms et des

Surfaces, CEN/Saclay, and SUNY-Stony Brook collaborated in this work.

39
Division 533, Technical Activities (cont'd)

Development of a Measurement Program to Use the Time Structure of the

Electron Beam at SURF

As a future project we are undertaking the development of a program

which makes use of the time structure of the beam at SURF. Many important

phenomena take place on a time scale between 10" 9 and lU _i3 second. For

example, typical chemical reactions and molecular vibration times are in

this time domain. In fact there is a whole new research area devoted to

studying phenomena occurring on the picosecond time scale. Lasers are ideally suited for this work. Unfortunately, conventional lasers do not

yet probe the VUV spectral range, and the lasers that do have such high

power that they often damage the specimen under study and only yield the

same number of photons/sec that one could obtain with synchrotron

radiation. Synchrotron radiation is a source of pulsed VUV radiation that

gently produces the excitation where chemical reactions can be easily

induced. Once this sample of excited molecules is produced, it can be

synchronously probed by a laser locked to the storage ring frequency.

The first step in this program is a study of the SURF electron bunch

profile and its stability. During the past year improvements to the RF

system have greatly improved the stability of the beam and reduced its

harmonic content. The next step in these experiments is to make simple

experiments to further test the feasibility of using SURF for these

experiments.

Surface Science

We have supported at SURF the establishment by the NBS Surface

Science Division of an experimental capability to study adsorbed molecules

on surfaces. These studies use several SURF monochromators and an ultrahigh vacuum system. Photon stimulated desorption (PSD) of ions is

being studied to understand the desorption mechanisms and energetics.

Vari abl e wavel ength ultraviolet photoemission spectroscopy (UPS) is also

utilized to characterize the surface species formed upon adsorption of the

molecules on clean metal and oxide substrates. Ion desorption mechanisms

for ionically and covalently bonded adsorbates are investigated.

Two important studies were completed last year. The first was a study of PSD from a single crystal of Ti0 2

. This compound is used as a model system for the theory of Auger-stimulated desorption. It was found

that ions desorb more readily from a defect surface than from the nearly

perfect surface. This is contrary to what current theory predicts and

shows the competition between electronic state and geometrical structure.

The reduced coordination of the oxygen atom with the Ti cation gives an enhanced ion yield and shows the importance of geometry in the desorption

probabi 1 ity

.

40
Division 533, Technical Activities (cont'd)

The second study involved orientation of CO adsorbed on a Cr (110)

surface. It was found that at low coverage the CO either lies flat or at

a very inclined angle to the surface. The UPS study verified the first

observation of inclined CO on a metal surface. At higher coverages or with coadsorption with oxygen, the CO stands upright. Presently, photon

stimulated ion desorption from the inclined or upright CO is being

studied.

Very High Resolution Spectroscopy at SURF

The National Science Foundation is partially supporting the

installation of a very high resolution, 6.65 m normal-incidence

spectrometer at SURF. The goal of this project is to do research on the

dynamics of energy transfer in atoms and molecules with an energy

resolution that is a factor of 10 better than photometric instruments

existing presently at synchrotron radiation facilities. In a collaborative effort, a similar instrument is being installed and

converted to photometric studies at the KEK Photon Factory in Japan.

These instruments will cover the 300-2000A spectral range with resolving

powers of 2xl05

. In addition, our instrument will provide highly

polarized radiation (polarization > 98% for X > 600 A).

This instrument is now installed at SURF. The beam line and its

optics have been commissioned. Polarization studies of the collection

optics have been completed and commissioning of the spectrometer was begun

by the University of Maryland and NRL staff in September 1985. The

University of Maryland and NRL staff are the principle investigators on

this program. SURF staff are contributing support to the project.

Expected NBS users are from the Centers of Radiation Research, Basic

Standards, and Chemical Physics. Outside users expressing interest in

using this facility are from NRL, Univ. of Maryland, ORNL, Yale, Argonne,

SUNY Binghamton, Ohio State, Univ. of Nebraska, Harvard College

Observatory, and Imperial College.

Electric Field Effects

This program studies the effect of electric fields on the absorption

cross sections of atoms and molecules at high photon energies. It will be

carried out, in the future, on the new 6.65 m high-resolution spectrometer

beam line. A cryopump-based, vacuum/gas handling system has been

completed to support these studies. We are beginning a series of

measurements to characterize the intensity and polarization of the

radiation coming down the new beam line.

41
Division 533, Technical Activities (cont'd)

While waiting for the high-resolution spectrometer to be ready, we

have carried out a study of the effect of electric fields on autoionizing

Ba states in an off-SURF experiment. These studies are made using three

dye laser excitation to reach odd parity states and two dye laser

excitation to reach even parity states. An example of the results

observed is the effect of an electric field on the 5d9p 3 P

i ° barium

resonance above the first ionization threshold. This relatively broad odd

parity autoionizing level is nearly degenerate with a much narrower even parity level. At moderate fields the sharp level produces an interference

dip in the broad level. At higher fields the interference eventually

gives rise to two split components. The effects on both even and odd

parity levels were observed and explained with a nonperturbative theory.

Effects of the electric field (with values up to 105 kV/cm) were observed

in other spectral regions of Ba. We are in the process of analyzing these

resul ts.

This work is a collaboration among SURF staff, the Atomic and Plasma

Radiation Division, and the Center for Basic Standards.

Photoabsorption of Laser-Ionized Species

The new time-resolved VUV absorption spectrometer, recognized with a 1984 I R- 100 award from Research and Development magazine, is performing

exceedingly well. This year, in collaboration with Prof. 8. Sonntag of

the University of Hamburg, we have obtained the first 3d photoabsorption

spectrum of laser-excited calcium (Ca: 4s4p 3 P

X

) and laser-ionized

calcium (Ca: 4s 2 S). Comparisons of these spectra with that of the

neutral ground state show some striking differences which we hope will

shed some light on the delicate dynamics of orbital collapse in the 3d

shell. Our next experiment will be on laser-excited and laser-ionized

manganese, a study which should solve the puzzle of the dramatic change in

3p-photoabsorpt ion between chromium and manganese.

This work, done in collaboration with the Atomic and Plasma Radiation

Division, also includes the development of laser-produced plasmas as intense, pulsed VUV sources. We have recently made the first

photoelectric measurements of the VUV radiation emitted by seven target

elements (Al, Cu, Sn, Sm, Vb, W, and Pb) of practical importance. Our

42
Division 533, Technical Activities (cont'd)

next step is to i nterconpare our results with those of the PTB group who

have calibrated a tungsten plasma source against the BESSY synchrotron.

This NBS-PTB i nterconp ari son w i 1 1 include the calibration of the PTB

instrument on SURF II and the measurement of the NBS 1 aser-produced source

by the PTB spectrometer. The goals of this work are to develop the 1 aser- produced plasma as a standard source and to develop criteria for the laser

parameters to ensure maximum reproducibility and reliability.

Ultrasensitive Trace Analysis

The collaboration with the Mass Spectrometry Group in the Center for

Analytical Chemistry has resulted in two major steps towards our goal of

improving isotopic abundance sensitivities from two to five orders-ofmagnitude utilizing the resonance ionization mass spectrometry (RIMS)

technique.

The first step has been the installation and operation of a new RIMS

system, including a new 12“-90° mass spectrometer of improved abundance

sensitivity and a second pulsed dye laser for two-color resonance

ionization. The second step has been the completion of the high

resolution pulsed dye amplifier system necessary to exploit the narrowly

spaced optical isotope shifts for isotope selection in the resonance

ionization process.

The newly installed system has been tested at low resolution in

studies of the doubly-excited 3pnd series in Mg. We have measured the

energy positions and autoionizing widths of this level by using a twocolor, two-step ionization process:

Mg(3s 2

) + ZRw^ Mg*(3snd)

Mg (3s nd) + hw 2^ Mg (3pnd)

jlf •ff The Mg (3pnd) autoionizing levels are of interest to those presently

studying the dielectronic recombination rates of Mg+ since a measurement

of the autoionization rate gives a measurement of the t ime-reversed

dielectronic recombination rate. Our experiments have again demonstrated

the power of the RIMS technique to produce spectroscopic measurements on relatively inaccessible states. We expect to start experiments on isotope

enhancement in the 6 Li/ 7 Li system in September 1985.

Atomic and Molecular Theory

Theoretical activity in the Far UV Physics Group is directed

primarily at problems associated with atomic and molecular photoabsorption

in the far ultraviolet spectral region and related topics such as excitation and ionization by charged particle impact. Recently, attention

43
Division 533, Technical Activities (cont'd)

has been given to multiphoton absorption processes, which afford an alternative means of accessing states in the same energy region.

During the past year we have been working, in collaboration with an experimental group at the Princeton Plasma Physics Laboratory, on some new approaches to generation of coherent radiation in the extreme ultraviolet

(XUV) spectral region. The Princeton group has had notable success in

obtaining amplified spontaneous emission of recombination radiation in

hydrogen-like carbon, at a wavelength of 18 nm. Our current work is

directed towards shorter wavelengths (less than 10 nm). The basic idea is

to use high-order multiphoton absorption processes to produce population

inversions in magnetically-confined ions, thus leading to amplified

spontaneous emission (i.e. , a soft x-ray laser). For example, there are transitions in krypton-like ions, in which a subvalence electron would be

excited by absorption of many (10 or more) ultraviolet photons from a KrF

excimer laser. Lasing action could then occur on transitions in which a valence electron drops into the subvalence hole. Our contribution to this

work consists of theoretical spectroscopy of the various candidate atomic

states, on most of which there exists no experimental information at

present; and rudimentary theoretical analysis of very-high-order

multiphoton processes. This latter subject is a focus of experimental

attention worldwide, but as yet does not have a good theoretical

u nderpi nni ng.

Other work on multiphoton processes is primarily spectroscopyoriented. We have published an analysis of an observation, by a group at

CEN Saclay, of a resonance in eight-photon, double ionization of calcium.

We are engaged in an analysis of two- and three-photon ionization of

magnesium. This, and most of our other efforts on multiphoton problems,

is done in a collaboration with the experimental program on ultrasensitive

trace analysis described above.

We are continuing to work on problems of multiply-excited states of

atoms and of Rydberg states in external fields. Work has begun on a comprehensive review of data on negative ion resonances, in collaboration

with groups at the University of Aarhus (Denmark) and the Australian

National University.

A workshop on Rydberg states in external fields and dielectronic

recombination was held here in October 1984. Its proceedings have been

publ ished.

S URF Radiometric Intercomparison

A second intercomparison between the silicon photodiode, tungsten

lamp, and synchrotron radiation irradiance scales was carried out in

collaboration with the Radiometric Physics Division using a transfer

44
Division 533, Technical Activities (cont'd)

radiometer. The closure was 1-2%, a little poorer than previously

obtained. It is now understood that very careful alignment of the

radiometer with respect to the SURF electron orbit plane is critical to

the measurement. The experiment will be repeated. This intercomparison

was carried out in the visible region of the spectrum.

Another intercomparison was carried out this year between SURF II and

the tungsten lamp irradiance scale at 297 nm using a uv spectroradiometer

designed by H. Kostkowski for NOAA as the transfer instrument. The

intercomparison was carried out by H. Kostkowski and J. Lean of the NOAA

team with collaboration by the SURF staff and staff from Divisions 531 and

534 in the Center for Radiation Research. Both the closure and accuracy

for this intercomparison was better than 2%. A publication is being

prepared.

Spectrometer Calibrations

SURF II is used as a primary standard of spectral irradiance for the

calibration of spectrometer and photometer systems in the spectral region

4-400 nm. These calibrations are primarily in support of programs of NASA

and DoE, but important calibrations this year of two instruments for

rocket -borne solar radiometry were also performed for NOAA. About 40

weeks in FY85 were utilized for 25 spectrometer calibrations including

instruments for NOAA, GSFC, LASP, NRL, Utah State University, Johns

Hopkins University, North Carolina State University, and Princeton

University. The facility is solidly scheduled well into FY86. NASA

support for this capability is expected to continue for the next five

years.

Far UV Detector Calibrations

For about 15 years, NBS transfer standard photodiode detectors for the

spectral range 5-320 nm have provided a radiometric base for users in such

fields as aeronomy, astronomy, and plasma, solar, and solid state physics.

During FY85, 16 calibrations were performed.

A new and improved far uv detector calibration system has been

designed, constructed, and installed at SURF and is in the final phases of

testing prior to performing outgoing calibrations. The system has

demonstrated the capability of producing much more rapid calibrations with

greatly improved spectral resolution and accuracy compared to the system

previously used.

45
Division 533, Technical Activities (cont'd)

ELECTRON PHYSICS GROUP

The Electron Physics Group has ongoing research efforts in electron

collision physics including electron-surface interactions, surface

magnetism, electron interaction theory, electron polarization phenomena,

electron-atom and electron-molecule collisions, and electron optics and

instrumentation. The wide applicability of electron-based measurement

technologies allows us to contribute to the solution of many diverse

scientific and technological problems.

The past year has been an exceptionally good one for the Electron

Physics Group. In last year's report, we described the strong interest in

surface magnetism emerging from the scientific and technological community

and the unusually good opportunities we saw to perform key experiments.

We undertook three major new experimental efforts and refocused some of

our ongoing projects. We felt that these new projects would position us

well over the next 3-5 years in our effort to develop and demonstrate the

basic measurement methods needed in this new field of research. We are finding that our predictions were correct, the only modifications being

that the impact of some of our efforts may be greater than we had imagined

and the time scale shorter than previously thought.

Inverse Photoemission

Our work on the scattering of spin-polarized electrons from surfaces

continues with a high level of activity. As a consequence of our advancement of polarized electron source and detector technology, our experiments are continually breaking new ground. This is particularly

true of our most recent work on surface magnetism. By using our polarized

electron gun to observe the effects of the exchange interaction, we are able to sense the local net alignment of spins in the surface of a ferromagnet. The short mean free paths for elastically scattered

electrons make this technique extremely surface-sensitive unlike neutron

scatteri ng.

Although in its infancy, inverse UV-photoemission has emerged as a very useful new method of gaining an understanding of the electronic

structure of surfaces in general, and of ferromagnetic surfaces in

particular. When used with the complementary method of photoemission

spectroscopy, it is possible to gain a complete picture of the electronic

structure.

The direct process, i.e., spin-polarized, angle-resolved, and energyresolved photoemission, is normally observed using a high intensity

synchrotron radiation source, a UV monochromator, an electron energy

analyzer, and a spin polarization detector. We have demonstrated that it

is possible to do the inverse experiment, where spin-polarized electrons

46
Division 533, Technical Activities (cont'd)

at a specific energy and angle of incidence are scattered from a target

and the UV photons at a selected wavelength are detected. With a nickel

(110) single crystal target, we demonstrated that only minority spin

electrons are absorbed into unfilled d-bands and give rise to UV photons.

This type of experiment allows one to observe the spin-polarized unfilled

states near the Fermi level. By varying the angle of incidence we also

measured the dispersion of these bands.

We continued our work in inverse photoemission by observing the

effects caused when atoms and molecules are absorbed onto a ferromagnetic

surface. We are interested in observing how the bonding of the absorbate

to a surface affects the unfilled d-band of the substrate and how the

magnetic character of the substrate changes. For atomic adsorption of

oxygen on a Ni(110) surface we found a dramatic reduction in the Ni 3d

minority holes, indicating that these states are strongly involved in the

chemisorption bond. For the molecular chemisorption of CO on Ni(110) we

saw a decrease in the Ni 3d minority states until one half of the surface

Ni atoms have a CO molecule bonded to them. This is due to a non-local,

chemisorption-induced reduction of the Ni magnetic moments. Transitions

to the COtt* band were also observed.

During the next year we will begin chemisorption experiments on the

Ni(100) surface. This surface is easier to treat theoretically and we

should be able to make detailed, direct comparisons with recent magnetic,

surface band structure calculations.

Spin Polarized Photoemission

One of the three new efforts is a collaboration with Neville Smith of

Bell Laboratories and Peter Johnson of Brookhaven National Laboratory. We

will be using the technique of spin-polarized, angle-resolved

photoemission to study surface magnetism. This has always been a powerful

experimental technique in the past, but one in which the combination of

low polarization detector efficiency and inadequate incident photon flux

made investigations very difficult. This has been changed now by the

advent of powerful new light sources and by our new, polarized electron

detector. We will be using the undulator beam port on the VUV-ring at

Brookhaven, which promises to offer the very high photon flux necessary

for this experiment. The polarization detectors we will provide have the

essential characteristics of high efficiency, small size, and low voltage

operation. While operating at only 150 volts they possess the same efficiency as the most efficient Mott polarization detectors which operate

at 120 KeV and which are not amenable to making angular measurements.

The apparatus is now under construction at Bell, Brookhaven, and NBS.

We have completed the electron optical design necessary to couple our

detector to the existing electron energy analyzer and have begun

47
Division 533, Technical Activities (cont'd)

construction of the polarization detectors. We hope, depending on

scheduling for the storage ring, to begin our measurements at Brookhaven

this wi nter.

New scientific opportunities are made possible by using the new, NBS

polarization detectors coupled with the intense photon flux of the

undulator beam line of the VUV-ring. These have attracted a great deal of

interest from the scientific community interested in surface magnetism.

As a result, a greatly expanded effort has been proposed involving three

national laboratories, four universities, Bell Labs, DOE, and NSF. This

effort will include studies of bulk materials as well as epitaxial

ferromagnetic mono-, b i - , tri-layers, etc. Investigations wil 1 include

ground-state magnetic properties, testing local -density-theory

predictions, surface magnetic critical phenomena, spin-dependent photoexcitation, and energy and wave-vector resolved electron spectroscopy.

There will also be a component of this research aimed at improving the

insertion device to further enhance the available photon flux. We expect

our existing experiment and instrumentation to serve as the prototype for

a much larger program to begin in 1-2 years.

Polarized Electron Microscopy

Magnetic devices are getting smaller and smaller, and thin-film

devices and media are becoming commonplace as the search for reliable,

high density information storage techniques becomes more intense. Optical

methods of studying magnetic phenomena are limited by diffraction to

resolutions above a few microns and also do not possess the surface

sensitivity that electron spectroscopies provide. There are, in addition,

very fundamental questions to be answered concerning the magnetism of very

small structures. For these reasons and others, we began our work on polarized electron microscopy.

As a result of our previous measurement of the spin polarization of

secondary electrons emitted from ferromagnetic materials, we decided that

it would be possible to measure the magnetization of surfaces with the

spatial resolution of a scanning electron microscope (SEM), i.e., in the

range 100-1000 A. This is because the secondary electrons emitted by

the highly focused incident electron beam retain their spin orientation

even after they are ejected from a magnetic surface. Hence, a measurement

of their polarization reflects the vector magnetization of the material

under the incident electron beam.

This year we completed the installation of three newly developed

polarization detectors on the HB50A scanning electron microscope belonging

to the NBS Center for Manufacturing Engineering (CME). In collaboration

with G. Hembree of the Micro and Optical Metrology Group (CME), we have

made preliminary observations of the magnetic domains of an iron-silicon

48
Division 533, Technical Activities (cont'd)

crystal using these detectors in both the pulse counting and analog mode.

Our results have been very encouraging. The magnetic domains of an ironsilicon sample are clearly visible with a high level of contrast, and the

magnetic imaging process is totally independent of the topographic image

formation, which is accomplished simultaneously. Hence, the influence of

physical structure on magnetic structure can be discerned and measured.

Our measurements were made with a 100 A diameter electron beam. This

promises to be the resolution limit of the technique after we eliminate

present sources of sample vibration. By comparison, conventional SEM

techniques give low contrast, do not measure vector magnetization, and

convolute topographic and magnetic information. Widely used optical

techniques are limited to 10,000 A resolution while a very great number of

scientifically challenging and technologically significant questions arise

below this resolution limit. A prime example is high density information

storage in magnetic media.

We are working to build joint research arrangements with industry,

other government 1 aboratories, and universities. This will make optimum

use of our unique capabilities in the near term and hasten the technology

transfer of this new measurement technique. To date, we have received a large number of inquiries, many offers of test samples, and a wide

exposure through meeting invitations and articles in the popular

scientific press.

Electron Transport Theory

The polarized secondary electrons that play the key role in our

magnetic imaging microscope possess a polarization which is a maximum for

very low emitted energies and then falls to a constant value at higher

secondary electron energies. The explanation for the shape of this curve

has eluded theorists until this year when Dave Penn, in collaboration with

Peter Apell (Guest Worker) and Steven Girvin (CCP), produced a theory

which not only explained the experimental results but allowed the

extraction of the ratio of the lifetimes of minority- to majority-spin

electrons directly from the data. The physical basis of the theory

involves the availability of holes for scattering of minority electrons at

low energy, which further polarizes the emitted beam through attrition.

Electron-Atom Collisions

We are investigating electron-atom scattering in an experiment where

all the parameters are determined so that we can make the step from

measuring cross sections to the more fundamental determination of quantum

phases and amplitudes. We have constructed a crossed beam, polarizedatom, pol arized-el ectro n scattering apparatus. Sodium atoms are polarized

by optical pumping with a CW-dye laser. The electron beam comes from a GaAs polarized electron source. The use of a laser to optically orient

49
Division 533, Technical Activities (cont'd)

the sodium beam also facilitates measurement of polarization of the beam

via laser fluorescence or Faraday rotation measurements. It is also

possible to use this laser to optically pump the sodium to an excited,

optically-oriented atomic state that could be studied by polarized

electron scattering. In this past year we made first use of this

capability to perform the first super-elastic, spin dependent measurements

in electron-atom scattering.

Super-elastic scattering occurs when an electron collides with an atomic excited state, de-excites the atom during the collision, and then

picks up the excitation energy. We used optical pumping to prepare an unpolarized beam of Na in the 3P state and studied the spin dependence of

the super-elastic process as a function of scattering angle, incident

energy, and the angle the peanut-shaped charge density of the Na atom made

with the incident electron direction. Surprisingly, there was a strong

dependence on incident electron spin direction. This spin asymmetry

varies as a function of energy and both the scattering and atomic charge

density orientation angles. We have found that this effect comes from a coupling between a spatial asymmetry in the super-elastic scattering cross section and the correlation of spin and angular momentum which occurs as a result of the optical pumping process. This new type of experiment

promises to be a very stringent test of our ability to calculate low

energy electron-atom interactions. Further, since it uniquely separates

the spin-exchange part of the scattering problem from other effects, it

should permit us to much better understand the role that exchange

interaction models play in scattering calculations.

Scanning Tunneling Microscopy

In collaboration with CME, we have begun a small pilot program aimed

at building a prototype scanning tunneling microscope to better understand

its operation, advantages, disadvantages, and applicability to the

solution of some outstanding problems in surface physics. Our first

instrument is a third generation STM closely following the successful

mechanical vibration isolation scheme used by IBM Zurich. We have

successfully operated the instrument in air, scanning gold and pyrolytic

graphite surfaces. We have observed regular structures from diffraction

gratings and diamond-turned gold surfaces, and have seen steps of atomic

dimensions on single crystal gold surfaces.

Our aim is to study the mechanisms of island formation and growth at

the sub-monolayer level. We are assembling an ultra-high vacuum system

with the necessary surface preparation and analysis systems, and expect to

couple this with our STM this year. Our overall goal is to correlate

surface microstructure with surface macroscopic properties. Areas of

interest include surface lattice structure of metal and semiconductor

50
Division 533, Technical Activities (cont'd)

crystal s, growth of

location of adsorbed gas molecules on surfaces,

metals on semiconductors.

and thin film

51
SPONSORED WORKSHOPS, CONFERENCES, AND SYMPOSIA

Division 533, Radiation Physics

C.W. Clark organized a workshop on Atomic Spectra and Collisions in

External Fields held at NBS, Gaithersburg, MD, on October 22-23, 1984.

R.P. Madden coordinated the following workshops: "Machine Workshop on the

6 GeV Synchrotron Radiation Source" and "Synchrotron Radiation Steering

Committee", NBS, Gaithersburg, MD, March 28-29, 1985.

52
INVITED TALKS

Division 533, Radiation Physics

1 .

2 .

3.

4 .

5.

6 .

7.

8 .

9.

10 .

11 .

Celotta, R. J., "Polarized Electron Scattering; A New Tool for

Surface Science," Colloquia, Braseleiro de Pesquisas Fisicas, Rio de

Janeiro, Brazil, October 5, 1984.

Celotta, R. J., "The Application of Polarized Electron Spectroscopy

to Surface Science," Colloquia, Instituto Politechnico National,

Mexico City, Mexico, October 9, 1984.

Celotta, R. J. , "Polarized Electrons: Recent Advances," Meeting of

Latin American Surface Scientists, Oaxaca, Mexico, October 10, 1984.

Celotta, R. J., "Spin Polarized Electrons," Colloquium, Physics

Department, Pennsylvania State University, University Park, PA,

December 6, 1984.

Celotta, R. J. , "Scanning Tunneling Microscopy," Solid State Physics

Seminar, Physics Department, Pennsylvania State University, State

College, PA, December 7, 1984.

Celotta, R. J. , "Electron-Atom Collision Experiments Using Optically

State Selected Beams," DEAP Annual Meeting, Norman, OK, May 29,

1985.

Celotta, R. J., "Scanning Tunneling Microscopy at NBS: A Progress

Report," International Workshop on Scanning Tunneling Microscopy, IBM

Europe Institute, Lech, Austria, July 2, 1985.

Celotta, R. J., "Recent Advances in Polarization Studies: Electron

Microscopy and Exchange Scattering," Colloquium, Ei dgenossi sche

Technische Hochschule, Zurich, Switzerland, July 9, 1985.

Clark, C.W., "Chemical and Spectroscopic Consequences of the

Lanthanide Contraction," Univ. of Illinois at Urbana-Champai gn,

Urbana, Illinois, February 5, 1985.

Clark, C.W., "Multiphoton Excitation of Autoionizing States," Argonne

National Laboratory, Argonne, Illinois, February 7, 1985.

Clark, C.W., "Autodetaching and Core-Excited States of Negative

Ions," Gordon Conference, Wolfeboro, New Hampshire, July 4, 1985.

53
Division 533, Invited Talks (cont'd)

12. Clark, C.W., "Highly Excited Atoms in Electric and Magnetic Fields,"

Los Alamos, New Mexico, June 4, 1985.

13. Ederer, D.L., "The Synchrotron Radiation Program at NBS," Lawrence

Berkeley Laboratory, Berkeley, California, March 13, 1985.

14. Ederer, D.L., "Photoionization of Laser-Excited Atoms by Synchrotron

Radiation," Lawrence Livermore National Laboratory, Livermore,

California, March 14, 1985.

15. Ederer, D.L., "A Review of the Synchrotron Radiation Program at NBSSURF," Photon Factory, Tsukuba, Japan, March 20, 1985.

16. Ederer, D.L., "Synchrotron Radiation as an Atomic Physics Probe," and

"The Synchrotron Radiation Program at NBS-SURF," Taipei, Taiwan,

March 20-25, 1985.

17. Ederer, D.L. , "Phun With Photoionization," Tsing Hua University,

Taiwan, March 26, 1985.

18. Ederer, D.L., "Hybrid Laser-Synchrotron Radiation Experiments in

Metal Vapors," University of Southern California, Los Angeles,

California, March 28, 1985.

19. Ederer, D.L., "Photoionization of Excited Atoms by Synchrotron Radiation: Sodium and Barium," Gordon Conference, Wolfeboro, New

Hampshire, July 3, 1985.

20. Feigerle, Charles S. , "Spin Polarized Inverse Photoemission Studies

of 0

2 Chemisorbed on Ni(110)," National Meeting of the Mexican Vacuum

Society, Taluca, Mexico, October 10, 1984.

21. Feigerle, Charles S. , "Spin Polarized Inverse Photoemission

Measurements of the Effect of Chemisorption on Ni : A Band Specific

Technique," Joint Institute for Laboratory Astrophysics, Boulder, CO,

October 15, 1984.

22. Feigerle, Charles S. , "The Electronic Structure of Transition Metals

in the Gas and Solid State, UCLA Department of Chemistry, Los

Angeles, CA, January 1 6, 1985.

54
Division 533, Invited Talks (cont'd)

23. Feigerle, Charles S. , "The Electronic Structure of Transition Metals

in the Gas and Solid State, University of Tennesse, Dept, of

Chemistry, Knoxville, TN, Februrary 18, 1985.

24. Feigerle, Charles S. , "The Electronic Structure of Transition Metals

in the Gas and Solid State, Oak Ridge National Laboratory, Oak Ridge,

TN, February 19, 1985.

25. Hughey, L.R., "Vacuum Compatibility Criteria Used at SURF -I I, the

NBS Electron Storage Ring," Fusion Technology Division of the

American Vacuum Society and NBS, Holiday Inn, Gaithersburg, MD,

May 7-9, 1985.

26. Klebanoff, L. K. , "Photoelectron Spectroscopy Studies of Cr(001)

Surface Magnetism," International Conference on Magnetism, San

Francisco, CA, August 27, 1985.

27. Kelley, M. H. , "Electron-Atom Collision Studies Using Optically State

Selected Beams," Symposium on Polarization and Correlation in

Electron-Atom Collisions, Pasadena, CA, August 2, 1985.

28. Lucatorto, T.B., and Mcllrath T.L. , "Techniques for Studying

Autoionization in Isoel ectronic and Isonuclear Sequences," Workshop

on Autoionization in Atoms and Small Molecules, Argonne National

Laboratory, Argonne, IL, May 2, 1985.

29. Lucatorto, T.B., "Techniques for Creating and Observing Atomic

Excited States and Ions: Applications to Atomic Structure," Physics

Department, University of California at Berkeley, May 14, 1985.

30. Lucatorto, T.B., "Techniques for Creating and Observing Atomic

Excited States and Ions: Applications to Atomic Structure," Applied

Physics Seminar, Stanford University, Stanford, California, May 15,

1985.

31. Madden, R.P., "SURF II Facility Up-Grade Plan," Synchrotron Radiation

Center User Meeting, Stoughton, Wisconsin, October 22, 1984.

32. Madden, R.P., "The SURF-II Facility Up-Grade Plan at NBS," NRC Committee on Atomic and Molecular Sciences (CAMS) Workshop on VUV and XRay Sources, National Academy of Sciences, Washington, DC,

November 9, 1984.

55
Division 533, Invited Talks (cont'd)

33. Madden, R.P., "Experimental Program at the NBS Synchrotron Ultraviolet Radiation Facility," Denton, Texas, November 12, 1984.

34. McClelland, J. J., "Observations of Spin Dependence in Superelastic

Scattering of Polarized Electrons from Na(3P)," XIV ICPEAC, Palo

Alto, CA, July 30, 1985.

35. Ott, W. R., "Dosimetry Research and Measurement Activities at NBS,"

Seminar for Metrology Technicians at Butler County Community College,

Butler, Pennsylvania, March 22, 1985.

36. Parr, A.C., "Molecular Photoionization Studies Using Synchrotron

Radiation," Lehigh University, Bethlehem, Pennsylvania, March 29,

1985.

37. Parr, A.C., "Molecular Photoionization Studies Using Synchrotron

Radiation", Los Alamos National Laboratory, Los Alamos, New Mexico,

May 2, 1985.

38. Penn, D. R., "Spin Polarization of Secondary Electrons," City College

of New York, NY, March 13, 1985.

39. Pierce, D. T. , "Chemisorption Induced Changes in Surface Magnetism

and Electronic Structure of Ni(110)," AT&T Bell Laboratories,

March 8, 1985.

40. Pierce, D. T. , "Spin Polarized Inverse Photoemission Studies of

Surface Magnetism and Electronic Structure," International Conference

on Magnetism, San Francisco, CA, August 1985.

41. Rakowsky, G. , "Coherent Synchrotron Relaxation Oscillation in an Electron Storage Ring," 1985 Particle Accelerator Conference,

Vancouver, British Columbia, Canada, May 15, 1985.

42. Alfred Seiler, "Connection Between Surface Magnetism and Electronic

Structure of Oxygen on Ni(llU), Magnetism and Magnetic Materials

Conference, November 29, 1984.

43. Unguris, J., "High Resolution Polarized Electron Microscopy," The

11th Colloquium on Magnetic Films and Surfaces, Asilomar, CA,

September 2, 1985.

56
PUBLICATIONS

Division 533, Radiation Physics

Bizau, J.M., Wuilleumier, W., Gerard, P. , Dhez, P. , Carrg, B., Spiess, G. , Ederer, D.L., Picqu§, J.L., LeGouSt, J.L. Keller, J.C., and Koch, P.,

Observation of Ionization of Laser Excited Atoms by Synchrotron Radiation,

Proc. IAU Colloquium 86 ; EUV and X-ray Spectroscopy, Astrophysical and

Laboratory Plasmas; ed. G. Doschek (August 1984).

Butler, J.J., Holland, D.M.P., Parr, A.C. , Stockbauer, R.L., and Buff, R. , Automation of the NBS Threshold Photoelectron-Photoion Coincidence Mass

Spectrometer, J. Phys E Sci. Instr. 18 , 286 (1985).

Carr§, B, Bizau, J.M., Cubaynes, D., Dhez, P. , Ederer, D.L. , Gerard, P.

,

Keller, J.C., Koch, P.M., LeGouet, J.L. Picqug, J.L., Roussell, F.,

Spiess, G. , and Wuilleumier, F., Collisional Ionization in a Resonantly

Excited Atomic Vapor, Proc. of Atomic and Molecular Collisions in a Laser

Field, Jour, de Physique, Colloque Cl, Supp. No. 1, 46, 163, January 1985.

Carrg, B., Bizau, J.M., Dhez, P., Ederer, D.L., Gerard, P. , Keller, J.C.,

Lock, P.M., LeGou'dt, J.L. Picqu§, J.L., Spiess, G. , and Wuilleumier, F.,

Electron Spectrometry Study of Associative and Penning Ionization in Laser

Excited Sodium Vapors, Optics Comm. 52_, 29 (1984).

Celotta, R.J., and Levine, J., Editors-in-Chief; Munday, J.A. , Rothman,

S.J., Fluss, M.H., and Smedskjaer, C., Editors, Methods of Experimental

Physics, 21, Solid State Physics: Nuclear Methods, Academic Press,

(1983).

Celotta, R.J., and Levine, J., Editors-in-Chief; Park, R.L., and Lagally,

M.G., Editors, Methods of Experimental Physics, 22, Solid State Physics:

Surfaces , Academic Press (1985).

Clark, C.W., Korevaar, E., and Littman, M.G., Quas i -Penni ng Resonances of

a Rydberg Electron in Crossed Electric and Magnetic Fields, Phys. Rev.

Lett. 54, 329 (1985).

Clark, C.W., Fassett, J.D., Lucatorto, T.B., Moore, L.J., and Smith, W.W.,

Observation of Autoionizing States of Beryllium by Resonance Ionization

Mass Spectrometry, J. Opt. Soc. Am. B. 2_, 891 (1985)

Clark, C.W., Electron-Atom Scattering in External Fields, Atomic

Excitation and Recombination in External Fields , ed. M.H. Nayfeh and C.W.

Clark (Harwood Academic 'Publishers, N.Y. 1985).

57
Division 533, Publications (cont'd.)

Cromer, C.L., Bridges, J.M., Lucatorto, T.B., and Roberts, J.R., A HighResolution VUV Spectrometer with Electronic Parallel Spectral Detector,

AIP Conf. Proc. 119 “Laser Techniques in the XUV," Boulder, CO, 180,

(1984).

Cromer, C.L. Bridges, R.M., Roberts. J.R., and Lucatorto, T.B., A HighResolution VUV Spectrometer with Multichannel Detector for Absorption

Studies of Transient Species, Appl. Opt. 24_, 20 (1984).

Cromer, C.L. and Clark, C.W., Resonant Structure in Multiphoton Ionization

of Calcium, J. Phys. B _18, L497 (1985).

Dehmer, J.L., Southworth, S.H., and Parr, A.C., Triply Differential

Photoelectron Studies of Resonances in Molecular Photoionization, NIM B 10

247 (1985). ~

Dehmer, J.L., Parr, A.C., Southworth, S.H., and Holland, D.M.P., AngleResolved Photoelectron Study of the Valence Levels of BF 3 in the Range 17

< hv < 28 eV, Phys. Rev. 22.» 1783 (1984).

Feigerle, C.S., Pierce, D.T., Seiler, A., and Celotta, R.J., An Intense

Source of Monochromatic Electrons: Photoemission from GaAs, Appl. Phys.

Lett. 44, 866 (1984).

Feigerle, C.S., Seiler, A., Peffa, J.L., Celotta, R.J., and Pierce, D.T.

,

Chemisorbed Oxygen on Ni(110) Studied by Spin Polarized Inverse

Photoemission, J. Vac. Sci. Technol. A, 3_(3), 1487 (1985).

Feigerle, C.S., Pierce, D.T. , Seiler, A., and Celotta, R.J., High

Current, Monochromatic Electron Source for Polarized Scattering, Int.

Conf. on Phys. of Electron and Atomic Collisions (ICPEAC), San Francisco,

CA (1985).

Greene, C.H. and Clark, C.W., Adiabatic Hyperspherical Treatment of

Lithium 2P° States, Phys. Rev. A. 30_ 2161 (1984).

Hill, W.T., Non-Resonant Laser-Driven Ionization of Condensing Vapors: A

Mechanism Based on Cluster Fragmentation, Optics Comm. 54, 283 (1985).

Kelley, M.H., Celotta, R.J., and Pierce, D.T., Electron-Atom Collision

Studies Using Optically State Selected Beams, Proceedings of Department of

Energy Workshop on Atomic Physics (1984).

Klose, J.Z., Bridges, J.M., and Ott, W.R., Monochromatic Source of Lyman

Alpha Radiation, Appl. Opt. 24_, 2039 (1985).

58
Division 533, Publications (cont'd.)

Leroi, G.E., Dehmer, J.L., Parr, A.C., and Poliakoff, E.D., Polarization

of Fluorescence: A Probe of Molecular Autoionization, Proc. of Israeli

Phys. Soc. 6, 207 (1983).

Madden, R.P., Ederer, D.L., and Parr, A.C., Experimental Program at NBS

Synchrotron Ultraviolet Radiation Facility, Proceedings of the Conference

on the Application of Accelerators in Research and Industry, Nucl. Inst,

and Meth. B10/11, 289-292 (1985).

McClelland, J.J. and Fink, M. , Electron Correlation and Binding Effects

in Measured Electron Scattering Cross Sections of C02 , Phys. Rev. Lett.

54, 2218 (1985).

McClelland, J.J. and Fink, M. , Correlation Effects in Neon Studied by

Elastic and Inelastic High-Energy Electron Scattering, Phys. Rev. A

1328 (1985).

McClelland, J.J. and Kelley, M.H., Detailed Look at Aspects of Optical

Pumping in Sodium, Phys. Rev. A, 31_(6), 3704 (1985).

McClelland, J.J., Kelley, M.H., and Celotta, R.J., Spin Dependence in

Superelastic Scattering from Na(3P), Phys. Rev. Lett. 55_, 688 (1985).

McClelland, J.J., and Kelley, M.H., Diagnosis of Spin Polarization in an Optically Pumped Sodium Beam, Proceedings, Int. Conf. on Physics of

Electron and Atomic Collisions (ICPEAC), San Francisco, CA (1985).

McClelland, J.J., Kelley, M.H., and Celotta, R.J., Electron-Atom Collision

Studies Using Optically State Selected Beams: Superelastic Scattering,

Proceedings, Symposium of Polarization and Correlation in Electron-Atom

Collisions (Abstract), Pasadena, CA (1985).

McClelland, J.J., Kelley, M.H., and Celotta, R.J., Observations of Spin

Dependence in Superelastic Scattering of Polarized Electrons from Na(3p),

International Conference on Physics of Electron and Atomic Collisions

(ICPEAC Invited Papers), San Francisco, CA (1985).

Nayfeh, M.H. and Clark, C.W., Introduction, Atomic Excitation and Recombi - nation in External Fields , ed. M.H. Nayfeh and C.W. Clark (Harwood

Academic Publishers, N.Y., 1985).

Penn, D.R., Wave-Number-Dependent Dielectric Function of a Semiconductor,

Citation Classic in Current Contents/Physical, Chemical & Earth Sciences,

25_(6) , 20 (1985).

59
Division 533, Publications (cont'd.)

Penn, D.R., Apell, S.P., and Girvin, G.M., Theory of Spin-Polarized

Secondary Electrons in Transition Metals, Phys. Rev. Lett. 55, 518

(1985). —

Pierce, D.T., and Celotta, R.J., Applications of Polarized Electron

Sources Utilizing Optical Orientation in Solids, in Optical Orientation , ed. F. Meier and P. Zakharchenya, part of the North Holland Series

"Modern Problems in Solid State Physics," Chapter 6, pp. 259 (1984).

Poliakoff, E.D., Dehmer J.L., Parr, A.C, and Leroi, G.E., "Fluorescence

Excitation Studies of Molecular Photoionization in External Electric

Fields," Proc. of Israeli Phys. Soc. 6_, 1207 (1983).

Saloman, E.B. Cooper, J.W., and Kelleher, D.E., Electric Field-Induced

Interferences in Autoionizing Resonances, Phys. Rev. Lett., 55, 193

(1985). ~

Schaefer, A.R., Saunders, R.D., and Hughey, L.R., Intercomparison

Between Independent Irradiance Scales Based on Silicon Photodiode

Physics, Gold Point Blackbody Radiation, and Synchrotron Radiation, SPIE

499 Opt. Rad. Meas. (1984).

Seiler, A., Feigerle, C.S., Pefia, J.L., Celotta, R.J., and Pierce, D.T.

,

Connection Between Surface Magnetism and Electronic Structure of Oxygen

on Ni(110), J. Appl. Phys. 57(1 ), 3638 (1985).

Unguris, J., Hembree, G.G. , Pierce, D.T., and Celotta, R.J., Scanning

Electron Microscopy with Secondary Electron Spin Polarization Analysis:

A New Probe of Magnetic Microstructure, Book of Abstracts, 45th Ann.

Conf. on Physical Electronics, University of Wisconsin, Milwaukee, WI,

pp. E-8 (1985).

Unguris, J., Pierce, D.T., and Celotta, R.J., Spin-Polarized Electron

Scattering Studies of the Ferromagnetic Glass, Fe 8i 5 B i4 5 Si 4 , Phys. Rev.

B 29(3), 1381 (1984).

60
PUBLICATIONS IN PREPARATION

Division 533, Radiation Physics

Bizau, J.M., Wuilleumier, F., Ederer, D.L., Keller, J.C., LeGouSt, J.L.,

Picqug, J.L., Carrg, B., and Koch, P., Oscillator Strength Measurements of

Even Parity Autoionization Resonances in Neutral Sodium from Combined

Synchrotron Radiation Laser Excitation (submitted to Phys. Rev. Lett).

Feigerle, C.S., Seiler, A., Pefla, J.L., Celotta, R.J., and Pierce, D.T.

,

CO Chemisorption on Ni(110): Effect on Ni Surface Magnetism and Formation

of Cott* Band, Phys. Rev. (submitted).

Hill, W.T., Quenching of Resonant Laser-Driven Ionization by High Buffer

Gas Pressures (submitted to J. Phys. B).

Klebanoff, L. , Robey, W.W., Liu, G. , Shirley, D.A., Photoelectron

Spectroscopy Studies of Cr(001 ) Near-Surface and Surface Magnetism,

Proceedings, Journal of Magnetism and Magnetic Materials (to be

pub! ished)

.

Krause, M.O., Svensson, W.A., Carlson, T.Z. , Leroi, G. , Ederer, D.E. , Holland, D.M.P., and Parr, A.C., Photoeffect in the 4d Subshell of Atomic

Silver Between 14 and 140 eV (submitted to J. Phys. B).

Mcllrath, T.J. and Lucatorto, T.B., Techniques for Studying Autoionization

in Isoel ectronic and Isonuclear Sequences (in progress).

Moore, L.J., Fassett, J.D., Travis, J.C., Lucatorto, T.B., and Clark,

C.W., Resonance Ionization Mass Spectrometry of Carbon, J. Opt. Soc. Am.

B 2_, Sec. 9 (to be published, September 1985).

Parr, A.C., Synchrotron Radiation: Applications to Chemistry, book

chapter in Analytical Techniques , to be published by Texas A & M

University Press.

Penn, D.R., Apel 1 , P.S., and S.M. Girvin, Spin Polarized Secondary

Electrons, Theory, Journal of Magnetism and Magnetic Materials,

(submitted).

Pierce, D.T., Seiler, A. Feigerle, C.S., Pefla, J.L., and Celotta, R.J.,

Spin Polarized Inverse Photoemission Studies of Surface Magnetism and

Electronic Structure, Proceedings, Journal of Magnetism and Magnetic

Materials (submitted).

61
Division 533, Publications in Preparation (cont'd.)

Rakowsky, G. , Coherent Synchrotron Relaxation Oscillation in an Electron

Storage Ring, to be published in IEEE Trans. Nucl. Sci.

Saloman, E.B., Cooper, J.W., and Mehlman, G, Photoabsorption of Barium

from 237.9 nm to 120 nm, Phys. Rev. (1985) (in press).

Saloman, E.B. and Hubbell, J.H., Critical Analysis of Soft X-Ray Cross

Section Data (Proc. of Third Int. Symp. on Radiation Physics, Ferrara,

Italy, 1985).

Seiler, A, Feigerle, C.S., Pe-na, J.L., Celotta, R.J., and D.T. Pierce,

Chemisorption Induced Changes in Surface Magnetism and Electronic

Structure: Oxygen on Ni (110) , Phys. Rev. Lett, (in press).

Seiler, A., Feigerle, C.S., Celotta, R.J., Pierce, D.T., and Smith, N.V.,

Spin Dependence of Unoccupied States on Ni(110), Phys. Rev. B (submitted).

Snyder, J.J., Lucatorto, T.B., Debenham, P.H., and Geltman, S. , Ultrasensitive Laser Isotope Analysis in an Ion Storage Ring (submitted to Opt.

Soc. of Am. B).

Taylor, K.T., Clark, C.W., and Fon, W.C, Electron Scattering by Neon in

Resonance Regions, J. Phys. B _18 (1985) (in press).

Unguris, J., Hembree, G.G. , Celotta, R.J., Pierce, D.T., High Resolution

Magnetic Microstructure Imaging Using Secondary Electron Spin Polarization

Analysis in a Scanning Electron Microscope, J. of Microscopy (in press).

Unguris, J., Hembree, G.G., Celotta, R.J., and D.T. Pierce, Investigations

of Magnetic Microstructures Using Scanning Electron Microscopy with Spin

Polarization Analysis, Proceedings, International Conference on Magnetism (1985), Journal of Magnetism and Magnetic Materials (submitted).

62
TECHNICAL AND PROFESSIONAL COMMITTEE PARTICIPATION

Division 533, Radiation Physics

Robert J. Celotta

Member, General Committee, International Conference on the Physics of

Electron and Atomic Collisions.

Member, NBS Computer Network Committee.

Co-chair, NBS Atomic Physics Colloquium Committee.

Member, DEAP Local Organizing Committee.

Michael H. Kelley

NBS Advisory Group for Graphics.

David L. Ederer

Member, Optics News Editorial Committee.

Member, Education Committee, Optical Society of America.

Thomas B. Lucatorto

Advisory Panel, 1986 Conference on Laser Techniques in the Extreme

Ul traviol et.

Co-chairman, 1989 ICPEAC Local Organizing Committee.

Robert P. Madden

Member SRC Users' Advisory Committee for the Stoughton Storage Rings

(Tantalus and Aladdin) of the University of Wisconsin).

Member, Advisory Editorial Board of Optics Communication .

Chairman, International Committee for the International Conference on

VUV Radiation Physics.

Member, Council of Scientific Society Presidents (CSSP) (terminated

12/31/84).

63
Division 533, Technical and Professional Committee Paricipation and

Leadership (cont'd)

Robert P. Madden (cont'd)

Member, CSSP Executive Committee, 1984 (terminated 12/31/84).

Member, Middle Atmospheric Program International Working Group on Solar Spectral Irradiance Measurements.

Coordinator, Council of U.S. Synchrotron Radiation Laboratory

Di rectors.

Member, International Committee of the International Conference on XRay and VUV Synchrotron Radiation Instruments.

Member, Optical Society of America Objectives and Policy Committee.

Member, Physics Today Advisory Committee of the American Institute of

Physics (terminated 12/31/84).

Member, Synchrotron Radiation Facility Working Group (Department of

Energy )

.

Member, Interagency Group for Intense Light Sources.

Member, U.S. Organizational Committee for the October 1985 Workshop

on the Construction and Commissioning of Dedicated Synchrotron

Radiation Facil ities.

Member, Synchrotron Radiation Source and Research Development

Co mmittee.

Thomas J. Mcllrath

Chairman, 1984 Meggers Award Committee, Optical Society of America.

Member, National Research Council Committee of Line Spectra of the

El ements--Atomi c Spectroscopy.

Vice Chairman, 1985 Gordon Conference on Atomic Physics.

Advisory Panel, 1986 Conference on Laser Techniques in the Extreme

U1 traviol et.

Advisory Editor, Laser Focus Magazine.

64
Division 533, Technical and Professional Committee Participation and

Leadership (cont'd)

Willi am R • Ot t

Member, International Working Group for Middle Atmosphere Program on

Solar Spectral Irradiance Measurements, 1981-1985.

Treasurer, Pro-tern Committee (now forming), International Radiation

Physics Society.

Member, International Advisory Board for 3rd International Symposium

on Radiation Physics, Ferrara, Italy, September, 1985.

Member, SBUV/METSAT Calibrations Advisory Committee, NASA Goddard

Space Flight Center, 1981-1985.

Member, NBS-CRR Calibrations Advisory Committee

Daniel T. Pierce

Executive Committee, Surface Science Division of the American Vacuum

So c i ety

Chairman, AVS Morton M. Traum Surface Science Student Award

Committee

Program Committee, 11th International Colloquium on Magnetic Films

and Surfaces, Asilomar, CA

International Organizing Committee, International Colloquium on

Magnetic Films and Surfaces

Vice Chairman, Gordon Conference on Electron Spectroscopy

65
MAJOR CONSULTING AND ADVISORY SERVICES

Division 533, Radiation Physics

1. R. J. Celotta and D. T. Pierce consulted on the production and

detection of polarized electrons with researchers from Brookhaven,

AT&T Bell Labs, University of Texas, Princeton, Kimball Physics

Corporation, Rice University, University of Oklahoma, City College of

New York, MIT, University of Adelaide (Australia), University of Mainz

(West Germany), and the Naval Research Laboratory.

2. C. W. Clark advises a group at Princeton Plasma Physics Laboratory on

atomic physics problems associated with x-ray laser development.

3. D. T. Pierce consulted with R. O'Handly, MIT, on utilizing a spin

detector with a cylindrical mirror energy analyzer for spin polarized

Auger measurements.

4. D. T. Pierce consulted with G. J. Lapeyer, Montana State University,

on construction of a spin polarized electron source.

66
JOURNAL EDITORSHIPS

Division 533, Radiation Physics

R.J. Celotta, Series Editor, Methods of Experimental Physics.

R.J. Celotta, Editorial Board, Review of Scientific Instruments.

D.T. Pierce, Editorial Board, Review of Scientific Instruments.

67
TRIPS SPONSORED BY OTHERS

Division 533, Radiation Physics

Robert J. Celotta gave a talk at the Colloquia, Instituto Politechnico

National, Mexico City, Mexico, October 9, 1984.

Robert J. Celotta gave an invited talk at the Meeting of Latin American

Surface Scientists, Oaxaca, Mexico, October 10, 1984.

Robert J. Celotta gave a colloquium to the Physics Department,

Pennsylvania State University, University Park, PA, December 6, 1984.

Robert J. Celotta presented a talk to the Solid State Physics Seminar,

Physics Department, Pennsylvania State University, State College, PA,

December 7, 1984.

Robert J. Celotta presented an invited talk to the International Workshop

on Scanning Tunneling Microscopy, IBM Europe Institute, Lech, Austria,

July 2, 1985.

Robert J. Celotta gave a colloquium, Eidgenossi sche Technische Hochschule,

Zurich, Switzerland, July 9, 1985.

C.W. Clark presented an invited seminar and visited research groups at

Argonne National Laboratory and the University of Illinois, February 3-9,

1985.

C.W. Clark consulted on X-ray Laser Development at Princeton Plasma

Physics Laboratory, Princeton, New Jersey, January 1-2, 1985.

C.W. Clark consulted on X-ray Laser Development at Princeton Plasma

Physics Laboratory, Princeton, New Jersey, June 12, 1985.

C.W. Clark consulted on X-ray Laser Development at Princeton Plasma

Physics Laboratory, Princeton, New Jersey, April 1, 1985.

C.W. Clark visited and presented a talk at Los Alamos National Laboratory,

Los Alamos, New Mexico, June 3-5, 1985.

C.W. Clark attended the Gordon Conference as an invited speaker,

Wolfeboro, New Hampshire, June 30-July 5, 1985.

C.W. Clark consulted on X-ray Laser Development at Princeton Plasma

Physics Laboratory, Princeton, New Jersey, September 19, 1985.

68
Division 533, Trips Sponsored by Others (cont'd)

D.L. Ederer attended the Gordon Conference as an invited speaker,

Wolfeboro, New Hampshire, June 30-July 5, 1985.

D.L. Ederer attended a workshop on the use of synchrotron radiation for

atomic and molecular physics and presented two lectures in Taipei, Taiwan;

he visited the Photon Factory in Tokyo, Japan and presented a lecture at

the user meeting, March 13-31, 1985.

Charles S. Feigerle presented an invited talk to the Joint Institute for

Laboratory Astrophysics, Boulder, CO, October 12, 1985.

Charles S. Feigerle presented an invited talk to the Department of

Chemistry, UCLA, Los Angeles, CA, January 8, 1985.

C.S. Feigerle presented invited talks at the University of Tennessee,

Knoxville, Tennessee and Oak Ridge National Laboratory, Oak Ridge,

Tennessee, February 17-19, 1985.

Michael H. Kelley gave a talk to the International Symposium on

Correlation and Polarization in Electron-Atom Collisions, Pasadena, CA,

August 1, 1985.

Leonard E. Klebanoff presented a talk to the 45th Conference on Physical

Electronics, Milwaukee, WI, June 17, 1985.

T.B. Lucatorto consulted and presented an invited talk at the University

of California, Berkeley, California, and Lawrence Livermore Laboratory,

Livermore, California, May 13-16, 1985.

T.B. Lucatorto attended a workshop on Autoionization of Atoms and Small

Molecules at Argonne National Laboratory, Chicago, Illinois, May 2-3,

1985.

R.P. Madden attended the National Laser User's Facility Steering Committee

at the University of Rochester, Rochester, New York, March 3-4, 1985.

R.P. Madden attended the Social Objectives and Policy (SOAP) Committee

meeting, the meeting on Optical Computing, and the meeting on Picosecond

Optoelectronics, Lake Tahoe, Nevada, March 12-27, 1985.

A.C. Parr consulted and gave an invited talk at Los Alamos National

Laboratory, Albuquerque, New Mexico, May 1-4, 1985

69
Division 533, Trips Sponsored by Others (cont'd)

David R. Penn presented a talk at the City College of New York, NY,

March 13, 1985.

Daniel T. Pierce presented a talk at AT&T Bell Laboratories, Murray Hill,

NJ, March 8, 1985.

John Unguris presented a talk to the 45th Annual Conference on Physical

Electronics, Milwaukee, WI, June 19, 1985.

John Unguris presented a talk to the International Conference on

Magnetism, San Francisco, CA, August 30, 1985.

B. Sonntag attended the DEAP conference as an invited speaker, Norman,

Oklahoma, May 28-31 , 1985.

B. Sonntag attended a workshop on Autoionization of Atoms and Small

Molecules at Argonne National Laboratory, Chicago, Illinois, May 1, 1985.

B. Sonntag attended the Gordon Conference as an invited speaker,

Wolfeboro, New Hampshire, June 30-July 5, 1985.

70
CALIBRATION SERVICES PERFORMED

Division 533, Radiation Physics

Type of Service Customer

Type*

SP 250

Item No.

Number of

Cal ibrations

or Tests

Far UV radiometric

transfer standard

detectors (photodiode cal ibrations)

1,4-8 N.A. 16

Total s 16

*Column 2: 1, calibration labs; 2, hospitals; 3, nuclear energy

establishments; 4, industry; 5, US government labs;

labs; 7, universities; 8, foreign governments.

Income

$ 23K

$ 23K

6, DoD

71
SPONSORED SEMINARS AND COLLOQUIA

Division 533, Radiation Physics

Best, Philip E., Physics Department, University of Connecticut, Storrs,

Connecticut, "Towards Improved Temporal Resolution in Electron

Spectrometry," October 19, 1984.

Hotop, Hartmut, Universitat Kai sersl autern. West Germany,

"Photoionization of Laser Excited Rare Gas Atoms," November 13, 1984.

de Vries, Mattanjah, University of Maryland, College Park, Maryland,

"Shedding Light on Atom-Molecule Collisions," November 15, 1984.

Cavagnero, Michael, University of Chicago, Chicago, Illinois,

"Correlations of Atomic Valence Electrons," January 8, 1985.

Baratoff, Alexis, IBM Zurich, Switzerland, "The Present Status of Scanning

Tunneling Microscopy," February 6, 1985.

Helman, J. S., Centro Brazileiro de Pasquisas Fisicos, Rio de Janeiro,

Brazil, "Spin Relaxation of Iron in Hemoprotei ns," March 21 , 1985.

Clauberg, Rolf, KFA Julich, W. Germany, "Determination of Finite

Temperature Short Range Magnetic Order in Itinerant Ferromagnets by Spin

Polarized Photoemission," April 1, 1985.

Leubner, Christoph, Institute for Theoretical Physics, University of

Innsbruck, Austria, "Accurate Synchrotron Spectra for Planar Strong Field

Wigglers With Arbitrary Field Variation," April 1, 1985.

Gradmann, U., Technical University of Clausthal, W. Germany, "Magnetism at

Surfaces and Interfaces," April 2, 1985.

Nenner, Irene, Commissariat a L'Energie Atomique, Centre d'Etudes

Nucleaire de Saclay, France, "Molecular Photoionization Using Synchrotron

Radiation at LURE," April 29, 1985.

Hansma, Paul, University of California at Santa Barbara, Santa Barbara,

California, June 13, 1985.

Azria, Richard, C.N.R.S. Laboratoire de Collisions Atomiques et

Moleculaire, Orsay, France, "Negative Ion Formation in Polar and Highly

Polar Molecules," June 17, 1985.

72
Sponsored Seminars and Colloquia (cont'd)

Chri stensen-Dal sgaard, Birte, H.C. Oersted Institut, University of

Copenhagen, Copenhagen, Denmark, "Correlation Effects in Negative Alkali

Ions," July 12, 1985.

Buckman, Stephen J., Research School of Physical Sciences, Australian

National University, Canberra, Australia, "Recent Experiments in ElectronAtom Scattering," July 22, 1985.

Riehle, F., Physikal i sch-Techni sche Bundesanstal t , Institut Berlin,

"Radiometric Measurements at BESSY," July 24, 1985

Sawatzky, George, University of Groningen, The Netherlands, "The

Electronic Structure, Bandgap, and Spectroscopic Properties of Transition

Metal Compounds," August 20, 1985.

Dhez, Pierre, LURE, University Paris-Sud, Orsay, France, "Progress in XUV

Multilayer Development: Survey of the Collective French Effort,"

August 29, 1985.

Guntherodt, G. , Universitat zu Kffl n, W. Germany, "Spin-Resolved

Photoemission and Electron Scattering from Itinerant Ferromagnets ,

September 1 1 ,1 985.

73

TECHNICAL ACTIVITIES

Division 534, Radiometric Physics

Task No. 15241: Advanced Optical Radiation Measurements

Task No. 15242: Maintenance and Dissemination of Optical Radiation

Measurements

Task No. 26107: Quantum Radiometry

INTRODUCTION

The Radiometric Physics Division of the Center for Radiation Research

is the primary unit within NBS for carrying out the traditional Bureau

role of promoting accurate, meaningful, and compatible optical radiation

measurements in the near-uv, visible, and near-ir spectral regions. The

Division is organizationally subdivided into four Groups:

Spectroradiometry and Optical Pyrometry. Conducts applied research

to develop new instrumentation and to improve and extend radiometric

and pyrometric standards and calibration procedures.

Spectrophotometry . Provides high-accuracy spectrophotometric measurements, standards, and measurement assurance procedures. Develops

new methods for the radiometric character!' zat ion of optical media and

components.

Photodetector Physics and Metrology . Develops new, detector-based

radiometric standards and methods to conplement and extend traditional, source-based radiometry.

Radiometric Measurement Services . Provides, improves, and extends

radiometric and photometric calibrations, implements measurement

assurance programs, and participates in radiometric

i ntercomparisons.

As will be seen from the following reports of the four Group Leaders, each

Group produced important results during FY 1985.

Division 534 has been responsive to the continuing emphasis by NBS

management on improved delivery of radiometric measurement services.

Calibration billings in pyrometry, radiometry, photometry, and spectrophotometry increased by 25% during FY 1985, turnaround times for detector

responsivity and other calibrations were reduced significantly, and new measurement services for spectrophotometry have been established. Research to extend the wavelength range of spectral irradiance calibrations

to 2400nm has been conpleted. Three new measurement facilities (the

photoelectric pyrometer, the detector response comparator, and the reference spectrofl uorimeter) are now ready for routine calibrations of

standards.

75
Division 534, Technical Activities (cont'd)

The Division plans further expansions of its metrology programs, and

has made the following changes in group responsibilities and personnel

assignments in order to facilitate this goal:

(a) The Spectroradiometry and Optical Pyrometry Group will

concentrate its efforts on providing the scientific and

technological basis for measurement services in radiometry. We

are currently seeking a new leader for this Group with a background in optics, experience in radiometry, commitment to

metrology, and leadership qualities.

(b) The responsibilities of the Photodetector Physics and Metrology

(formerly Quantum Radiometry) Group have been broadened to

include the development and implementation of detector applications in addition to performing basic research on the physics of

detectors. Belzer, Thomas, and Zalewski have been assigned to

this Group.

(c) The Radiometric Measurement Services (formerly Calibrations)

Group has assumed responsibility for the new photoelectric

pyrometer the development of expanded pyrometric calibration

services. Booker and Waters have been assigned to this Group.

In order to ensure the relevance and effectiveness of these expanded programs, the Division has requested the Council for Optical Radiation Measurements (CORM) to update its 1982 report on "Pressing Problems and Projected National Needs in Optical Radiation Measurements". CORM has

responded by establishing a task force to develop project proposals for

implementation by our Division and ranking them by degree of need, appropriateness, probability of success, and urgency of need. The task force

report is expected to become available in October 1985 and will be given

prime consideration in formulating our future plans.

Our commitment to explore new technologies through basic research,

and to apply the results to our metrology mission, remains unchanged. The

rapidly expanding use of electro-optical devices in communication, instrumentation, and information processing has created calibration needs that

are not being met in a cost-effective manner by traditional approaches.

These needs are surfacing in a variety of commercial applications, in DOD

weapons systems and countermeasures programs. We are responding to these

needs by developing a body of scientific knowledge to support the establishment of photodetector standards for visible, near ultraviolet and near infrared radiometry. This is achieved by (1) conducting key experiments

to identify the physics pertinent to the performance of standard photodiodes, (2) developing theoretical models of photodiode performance that

76
Division b34. Technical Activities (cont'd)

incorporate the pertinent physics, and (3) developing innovative processing steps and novel photodiode structures based on the predictions of

the theoretical models. A significant portion of this work is carried out

in col 1 aborat ion with other national standards 1 aboratori es , universities,

and industrial contractors.

Our staff continues to be engaged in numerous interactions with

standardizing 1 aboratories, professional societies and voluntary standards

organizations at the national and international levels. For example:

The Radiometric Measurement Services and Photodetector Physics and

Metrology Groups are participating in international i nterconpari

sons organized by the Consultative Committee on Photometry and

Radiometry (CCPR) to evaluate the effectiveness of the 1979 redefinition of the candela. During FY 1985, the Division completed

initial measurements of intercomparison lamps and completed the

design and construction of intercomparison detector packages.

• Several Division employees serve on international committees, such

as the International Commission on Illumination (CIE), which are concerned with the development of new measurement methods and

standards for radiometry and spectrophotometry.

o The exchange program between our Division and the Physi kal i sc hTechnische Bundesanstal t (PTB) of the Federal Republic of Germany

continued in FY 1985. Drs. Moestl and Stock from the PTB Radiometry Laboratory pursued topics of detector physics in our laboratories, and Robert D. Saunders is currently working at PTB on topics of absolute radiometry. The purpose of these exchanges is

to make each institution thoroughly aware of the instrumentation

and measurement technology used by the other.

As in previous years, a number of guest scientists have worked with

us on projects of mutual interest:

Dr. Joaquin Campos Acosta from the Institute of Optics in Madrid,

Spain, worked on setting up a CO2 laser-based detector characterization facility for the infrared.

Messrs. Sheng-Tsong Chang and Chang-Long Chang from the National

Science Council of Taiwan participated in the development of

spectrophotometric standards.

Dr. Gyorgy Eppledauer from the Institute for Technical Physics of the

Hungarian Academy of Science worked on the self-calibration of

silicon photodiodes.

77
Division 534, Technical Activities (cont'd)

Professor He Ming-Gao from the Institute for Electric Light Sources

of Fudan University, Shanghai, PRC, collaborated on the intermediate

laboratory support program for geometri cal ly-total spectral flux.

Dr. Henry Kostkowski, Spectroradiometry Consulting, McLean, VA, and

Dr. Judith Lean, University of Colorado, characterized and calibrated

a spectroradiometer for rocket-borne measurements of solar spectral

irradiance in the 120 to 400nm region of the ultraviolet spectrum (in

collaboration with Divisions 531 and 533).

Drs. Klaus Moestl and Klaus Stock from the Physikal isch-Technische

Bundesanstal t in Braunschweig, FRG, performed studies of silicon

photodiode stability.

Mr. Fred Nicodemus, Catholic University of America, Washington, DC,

edited the Self-Study Manual on Optical Radiation Measurements.

Mr. Yoshihiro Ohno of the Matsushita Electric Industrial Company in

Osaka, Japan, worked on characterizing the throughput of small

integrating spheres for measurements of geometrically total luminous

flux.

Dr. Zhang Rui-Rong of the Shanghai Institute of Technical Physics,

PRC, undertook a study of silicon photodiode stability.

Their valuable contributions to our programs are acknowledged with thanks.

78
Division 534, Technical Activities (cont'd)

SPECTRORADIQMETRY AND OPTICAL PYROMETRY (E. F. Zalewski, K. D. Mielenz)

The Spectroradiometry and Optical Pyrometry group performs research

to utilize the most promising advancements in radiometric technology. The

main output of the Group is the development of new instrumentation and

techniques for radiation thermometry (optical pyrometry) and for the spectroradiometry of sources and detectors of optical radiation. In addition,

the group performs special tests of calibrations to assist the radiometric

community (most often other government agencies) in the area of highaccuracy radiometry.

Pyrometry

The most significant change in this program has been the redirection

of its immediate goal to that of producing an instrument strictly for

pyrometry lamp calibrations and temperature scale realizations. The experiment to compare the freezing points of silver and gold was turned over

entirely to the optical -fiber-thermometry project to allow the new pyrometer to be brought on-line to relieve the overburdening of FASCAL

(Facility for Automatic Spectroradiometric Calibrations). Waters will

comlete the first lamp-to-lamp comparison calibrations and the instrument

will be transferred to the Measurement Services Group before the end of

FY 85.

To meet the needs of the infrared radiation thermometry community,

Popenoe and Yokley are working on a project to build new types of

blackbody standards utilizing heat-pipe technology. Two types of heatpipe blackbodies are under construction: a sodium-filled one to cover the

temperature range from 5UUC to 1100C, and a mercury-filled one to cover

200C to 350C range. The heat-pipe is designed to assure that the cavity

temperature is the same as that sensed by the thermocouple or other

contact thermometer in another area of the heat-pipe. In addition, the

heat-pipe effect enables the construction of high-emissivity cavities

having a reasonable large size aperture. After testing and evaluation of

the quality of these blackbodies, they will form the basis for a proposed

facility to calibrate radiation temperature, spectral radiance and

spectral irradiance of infrared sources.

During this past year, Zalewski organized a one-day session of the

CORN meeting that focused on pyrometry and infrared radiometry. This

session brought together for the first time the radiation thermometry

community and CORM, and also strengthened the realtionship between the

radiation thermometry community and the Radiometric Physics Division. The

meeting emphasized the need for ir radiation temperature standards and a more active role for NBS in this area. At present NBS is routinely providing a measurement base for visible pyrometry only. There is hope for

79
Division 534, Technical Activities (cont'd)

some improvement in ir radiation thermometry stemming from the project to

develop blackbody standards using heat pipe technology, but what is needed

is a complete program at NBS headed by a senior staff member with a solid

background in radiometry and thermometry.

The ASTM committee on radiation thermometry has undertaken a project

to write a manual on how to use radiation thermometers correctly.

Zalewski has become active on this committee and is contributing to two of

the chapters in this book: one on the conceptual basis of the measurements and the other on standards and calibration practice.

Absolute Determination of Gold Point

Preparations for an experiment using absolute radiometry to measure

the melting point of gold were begun by Saunders and Shumaker during the

summer. All of the NBS spectroradiometric scales are currently based upon

the gold point and the present assessment among national laboratories is

that this temperature (1337.6 K) is uncertain by about 0.5° (corresponding

to a radiometric uncertainty of roughly 0.5% in the visible). The planned

experiment is much more direct than the few previous links between

absolute radiometry and the temperature scale, and should significantly

improve the present comparison uncertainty of about 1°. At the heart of

the experiment is a 1 aser-i rradiated integrating sphere whose exit port

radiance will be calculated from irradiance measurements made,

redundantly, with both an absolute silicon diode and an electrically

calibrated radiometer (ECR). This radiance will then be compared with

that of a blackbody at the gold point using a spectroradiometer. A new heat-pipe, gold-point furnace has been constructed with an easily

interchangeable crucible so that geometrical parameters can be changed to

permit some verification of the cavity blackness. The necessary lasers

have been acquired and the characterization of the spectroradiometer (slit

function and linearity measurements) has been begun. The characterization

of the ECR is being started by R. D. Saunders while a guest worker at PTB

this fal 1

.

Infrared Radiometry

Yokley and Ward completed the calibration of a variable (near ambient

temperature ir source in an experiment that also i ntercompared two

blackbody standards. One of these had been built by Yokley for the Air

Force Metrology Lab and was of a design similar to the NBS standard to

which it was compared. A temperature difference of 0.2°C (at 50°C) was

observed. This difference was larger than the expected uncertainty in the

blackbodies and is most likely due to the ir radiometer used to intercompare the blackbodies. Characteri zat ion experiments on the radiometer

prior to the blackbody intercomparison showed a rather large f iel d-of-view

error. Since the radiometer was Navy property and designed for field

80
Division 534, Technical Activities (cont'd)

applications, it was not suitable for high-accuracy work nor was it possible to carry out extensive modifications. Future work in the ir should

focus on optimization of a radiometer specifically for calibration

purposes.

Work on extending our ir detector calibration capability was begun.

Thomas completed a series of measurements to extend the calibration range

of several ECPRs (electrically calibrated pyroelectric radiometers) to

3.4ym. A radiant power i ntercompari son of the ECPRs at this wavelength

showed agreement to within 1%. The ir calibration factors of the ECPRs

agreed to within the precision of the radiometers.

Other work on extending our ir detector calibration capability to the

10pm region is now underway. Dr. Joaquin Campos, a guest worker from the

Institute of Optics in Madrid, is setting up a CO2 laser based detector

characterization facility in col 1 aboration w it h Belzer and Brubaker. The

initial experiments planned for this year are to measure the linearity and

absolute response of a commercially available ir detector (HgCdTe and/or

pyroelectric).

Spectroradiometry

For the past dozen years the NBS spectral irradiance scale has been

derived from the spectral radiance scale by a method which, in its extension into the infrared, is limited to about 1.6 micrometers because of

inadequate signal levels at longer wavelengths. During 1985, Saunders,

Shumaker, and Walker developed a new technique which overcomes this

difficulty and permits the realization of the spectral irradiance scale to

2.5 micrometers. It involves the use of a 1 amp-i rradi ated integrating

sphere with a carefully measured exit port area. Measurement of the exit

port spectral radiance then permits this sphere source to be used as a source of known spectral irradiance. The first routine lamp calibrations

on FASCAL using this technique are scheduled for October 1985.

Last year, we reported on a project to design a calibration procedure

for x-ray film sensitometry for the National Center for Devices and

Radiological Health (NCDRH). A prototype exposure meter devised by

Zalewski and Hattenburg was delivered to the NCDRH and demonstrated to be

a significant improvement over the calibration procedure they were

currently using. An improved version of the exposure meter was built by

Brubaker based on an integration circuit designed by Fowler and Campos.

Brubaker and Hattenburg demonstrated this final version at the NCDRH. The

result was a decrease in the time required to perform the calibration from

hours to minutes, plus approximately an order of magnitude increase in

measurement precision. The project leader at NCDRH commended this

extremely significant contribution to the NCDRH effort to reduce patient

x-ray exposure levels.

81
Division 534, Technical Activities (cont'd)

The project to examine the feasiblity of using a pulse dye laser

(PDL) to measure the relative spectral response of a narrow band

radiometer was completed this year by Campos. He did a complete characterization of the PDL and the pulse response characteristics of the

detectors. The limitations on the measurement were due to the characteristics of the particular PDL being used: the variability in its wavelength setting and the large amount of background (fluorescence) radiation

in the PDL output. These conclusions were tested by comparing the PDL

based spectral response measurements to those based on much higher

accuracy cw dye laser techniques. Agreement was within the expected level

of uncertainty. However, these experiments showed that a significantly

better (more expensive and non-t ransportabl e) PDL would be required to do

narrow-band spectroradiometer calibrations at an acceptable uncertainty

1 evel

.

An equipment failure on FASCAL during this year required that Popenoe

redesign some of the instrumentation because of the unavailability of

replacement parts.

Photodetectors

Houston and Saunders completed the development of the Division's new detector spectral response comparator and placed the instrument into operation in 1985. It consists of an argon mini-arc, a prism-grating double

monochromator with U.01 nm resolution, and a mirror system to collect,

monitor, and image the output beam onto the test detector. The new instrument has been used to put the detector calibration (DRIP) program on

a routine basis, resulting in a significant reduction of calibration turnaround times. It was also used to perform research measurements for the

Photodetector Physics and Metrology Group, as discussed in that Group's

report.

Thomas performed characterization measurements on the second

generation 1U0% quantum efficient devices (QED-200) recently introduced by

the United Detector Technology Company. The design changes were suggested

by Zalewski and Duda (UDT Co.) in their original publication describing

these devices. Significant improvements in field of view, spectral range,

polarization insensitivity and ease of alignment were achieved. This

device has been recognized as one of the significant new commercial developments of 1984. NBS and UDT will jointly receive the IR-10U award for

this work.

Belzer completed the design and construction of the circuit boards

for the CCPR/CIE intercomparison detectors. Belzer and Brubaker completed

the mechanical drawings for the detector housing and the construction of

the prototype. Testing of the prototype was completed by Booker and

Cornett (summer employee engaged in the optical fiber thermometer

82
Division b34, Technical Activities (cont'd)

project). Delivery of the remaining detector housings, however, is

several months behind schedule. As soon as the housings are received

construction of the intercomparison detectors can be completed and the

i ntercompari son measurements initiated. It is hoped that the first stage

of the intercomparison will begin by November.

Thomas has taken up the project to analyze the DRIP intercomparison

data. This was a project, started by Warren Gladden before he left the

Division, designed to diagnose measurement problems of NBS detector

calibration customers. Dr. Zhang, a guest worker from the Shanghai

Institute of Technical Physics, and Belzer have undertaken a study of

silicon photodiode cleaning techniques and reflectance stability.

83
Division 534, Technical Activities (cont'd)

SPECTROPHOTOMETRY (J. J. Hsia)

The Spectrophotometry group is responsible for:

(1) Establishing and improving high-accuracy spectrophotometric and

densitometric scales in the National Measurement System by developing

new instrumentation, establishing new measurement capabilities, and

improving basic standards.

(2) Disseminating these scales by developing transfer standards and

standard materials, establishing measurement assurance programs,

performing calibration services, and providing consultation to the

measurement community.

(3) Studying and developing new methods for radiometric characterization

of optical media and components for scientific research and for

emerging technologies.

FY 1985 has been another productive year of the Group. Major accomplishments in measurement services, spectrofl uorimet ry , infrared spectrophotometry, optical densitometry, and standards committee work were made

as presented below.

Measurement Services

Patricia Barnes, who joined the Group in August 1984, and Weidner

provided special calibration of spectral transmittance, spectral specular

reflectance, and spectral diffuse reflectance. They also produced

aluminum-mirror, specul ar-refl ectance SRM's. Eckerle provided measurement assurance for retroref 1 ectance, a new measurement service.

A new Standard Reference Material No. 2034, holmium oxide in

perchloric solution, was developed by Weidner, Mavrodi neanu , Mielenz,

Velapoldi, Eckerle, and Adams. The SRM was produced by Weidner,

Mavrodineanu and Barnes. It is to be used to calibrate the wavelength

scale of spectrophotometers from 241 to 640 nm.

A new measurement assurance service for transmittance was established

by Eckerle, Hsia, and Weidner. This service assesses the accuracy of

spectral transmittance measurement capabilities from 92% to 0.1% in the

visible spectral region.

Weidner initiated and started research on oxide mixtures as wavelength standards for spectral refl ectometers in the near infrared range.

84
Division 534, Technical Activities (cont'd)

To facilitate the dissemination of spectrophotometric scales, Hsia

and Mielenz participated in the CORM/NBS task force on intermediate

laboratories. The task force specifies and ranks needs for transfer

standards and calibrations to be supplied by intermediate laboratories,

and identifies private laboratories that can serve as intermediate

calibration laboratories for spectrophotometry.

Spectrof 1 uorimetry

The goal of this project is the performance assessment of instruments

for fluorescence measurements in non-destructive testing, appearance

measurements, and analytical chemistry. The main efforts are to develop

the NBS reference spectrofl uorimeter and to develop standard materials.

Eckerle and Chang, a guest worker from the Taiwan National Science

Council, characterized the reference spectrofluorimeter for wavelength

accuracy, stray radiant energy, and linearity. They measured its relative spectral response by two methods - using an NBS tungsten-strip standard lamp, and an NBS standard silicon photodiode. Preliminary technical

emission spectra for quinine sulfate dihydrate were obtained.

A commercial fl uorimeter was purchased and modified to conform to

ASTM standards. An ASTM round-robin test to evaluate three liquid dye

penetrants was performed in collaboration with L. J. Swatzendruber, CMS.

Solutions of different concentrations were measured, and thermal and

ultraviolet fading tests were done.

Infrared Spectrophotometry

The purpose of the long-wavelength infrared spect rophotomet ry project

is to establish IR measurement services from 2.5 to 25ym for transmittance, diffuse reflectance and specular reflectance. This is done

through the development of an LWIR spectrophotometer and studies of the

principles and practices of Fourier transform spectroscopy (FTS).

Weidner designed and installed support systems for the Fourier

scanning i nterferometer spectrometer and the specular and diffuse reflectometers attachments. This allows the spectrometer to be moved along a five-foot track so that the collimated i nf rared beam can enter either the

specular refl ectometer or the diffuse refl ectometer. These reflectometers were assembled and enclosed so that the system can be purged of

water vapor and carbon dioxide. The air-dryer filter system required for

the purging is operational. The signal throughput of the specular

refl ectometer was tested with a liquid-nitrogen cooled HgCdTe detector

(with detection surface facing down), and was found satisfactory. The

detector for the diffuse ref 1 ectometer will be tested as soon as the

proper high-pressure connections are completed and will allow ultra-pure

85
Division 534, Technical Activities (cont'd)

nitrogen gas to be supplied to the Joul e-Thompson cryostat-HgCdTe detector through a filter. This second detector has its detection surface

facing up. Once the connections are made, Weidner will test the signal

throughput of the diffuse refl ectometer. If this test is satisfactory, he

will be ready to proceed with performance checks.

Cohen has completed a draft document. Introduction to Fourier

Transform Spectroscopy . This simple, concise document is organized into

three parts: a selective review of Fourier transform mathematics, a treatment of the physics of Michel son i nterferometry , and topics in

Fourier transform spectroscopy. The next phase will be an analysis of

the practical aspects of Fourier transform spectroscopy, as effected by

actual operational factors.

Optical Densitometry

The project on opt ical -density measurements with an inverse-fourth

instrument is progressing. In FY85, efforts by Popenoe and Fink included

resolving the problem of the optical zero-offset distance, designing and

constructing the opal-diffuser collecting system, and comparing opaldiffuser and i ntegrat i ng-sphere collection systems.

Through realignment of the optical system, refinement of the measurement procedure and modified software, the optical zero-offset distance is now a constant and is independent of the optical density of the filter

employed.

To conform to the new ISO Standard 5/2-1985. (“Photography-Density

Measurements - Part 2: Geometric Conditions for Transmission density"),

an opal -diffuser collection system was designed and constructed. This

system consists of an opal glass, a sample plate with grooves for

applying vacuum and pressure, and a specular-aluminum-hemispherical

collector for diffuse light.

Measurements of photographic and x-ray step tablets using both opaldiffuser and i ntegrat i ng-sphere collection systems were performed. Preliminary data indicated that, below optical density one, measurements

made with the opal-diffuser gave lower optical densities than those made

with the integrating sphere. These differences are expected since the

opal diffuser introduces i nterrefl ect ions between the sample surface and

the opal diffuser. These differences are consistent with measurements

made by PTB, West Germany.

Fink continued to produce x-ray film and photographic step tablets

used in the calibration of optical densitometers (OD from 0 to 4) and

microcopy resolution charts for determining the resolving power of

microscopy systems.

86
Division 534, Technical Activities (cont'd)

Standards Committee Work

During the past year, Cohen collaborated with ASTM committee E7.10.04

on i nf rared methods, particularly on the compilation of a glossary for ir

thermography for NOT and a draft standard test method for minimum

resolvable temperature difference (MRTD). Cohen's talks and publications

have apparently motivated one major manufacturer of thermal imaging

systems to provide more complete and meaningful performance

specifications. His attempts to measure the spatial distribution of

temperature of targets were unsuccessful owing to a malfunctioning spot

radiometer. The measurements will be repeated pending the availability

of a suitable instrument. It appears feasible to utilize CBT's

laboratory facility for carrying out the objectives of this work.

Hsia was elected to the Board of Directors of the Inter-Society Color

Council, an inter-disciplinary organization of more than 20 scientific,

artistic and industrial societies which have common problems of color and

appearance.

As an Associate Director of CIE Division 2 on Physical Measurement of

Light and Radiation, Hsia has established three new committtees on

fluorescence, retroref 1 ectance, and gloss.

87
Division 534, Technical Activities (cont'd)

PHOTQDETECTQR PHYSICS AND METROLOCY (J. GEIST)

During FY85, this Group was responsible for performing research to

identify and develop new approaches to radiometric measurements and

standards.

Detector Physics

A very accurate verification of the original self-calibration

technique has been reported by Nigel Fox at the UK NPL. He selfcalibrated two EG&G UV444B photodiodes at 676.4 nm to the best possible

precision and conpared them with an NPL transfer standard thermopile that

had been calibrated against the new NPL Electrically Calibrated Cryogenic

Cavity Radiometer (ECCCR). The estimated accuracy of the latter

instrument is 0.01% with respect to the SI units and the self-calibration

of both diodes agreed with the ECCCR based calibration to within 0.02%.

This may be somewhat fortuitous, because there are some questions about

the accuracy of sel f-cal ibrat ion physics at this level. For this

reason. Fox is preparing a more extensive intercomparison that will

involve more wavelengths and more photodiodes, as well as direct

comparison with the ECCCR, rather than comparison through a transfer

standard.

This verification of silicon physics as a basis for radiometric

calibration at the highest levels of accuracy highlights the importance of

developing stable, 100% quantum efficiency Si based radiometers. The

evolution of self-calibration is necessary if we are to disseminate

spectral flux calibrations to the broadest user community with minimum

complexity, expense and degradation of accuracy.

Toward this end, we have completed evaluation of the UDT QED 200 100%

quantum efficiency radiometers. Their optical performance is excellent.

They accommodate a sufficiently wide field of view to be used to calibrate

the spectral power at the image of the exit slit of a monochromator, and

they have a quantum efficiency of greater than 99.7% at 633 nm. However,

the requirement of reverse bias to achieve 100% quantum efficiency

remains inconvenient, and the flux level at which 100% quantum efficiency

can be achieved may decrease with time. Both of these problems are associated with the inversion layer diode structure, which seems to

provide only a limited solution to the problems of 100% quantum efficiency

and stability of response after exposure to uv radiation. While other

diodes lose their uv response with uv exposure, inversion layer diodes

retain their high internal quantum efficiency throughout the uv and

visible, but only at low flux levels. Exposure to uv and other forms of

oxide stress, possibly including the passage of time, seem to convert

strong inversion to weak inversion, thereby lowering the maximum flux

level at which the inversion layer diodes remain linear in response.

88
Division 534, Technical Activities (cont'd)

Saunders and Houston have completed an experimental survey of the

internal quantum efficiency of some commercially available silicon

photodiodes and some experimental structures. They have discovered a number of devices whose internal quantum efficiency is within five percent

of unity from 350 nm to 950 nm. Some of the same devices have maintained

their high quantum efficiency during more than 24 hours exposure to 1 mW

per square cm of 254 nm wavelength uv radiation.

The recent improvements in silicon fabrication technology that are

evident from the results of the recent internal quantum efficiency

survey, and the growing recognition of the problems with inversion layer

diodes, make this an ideal time for the development of silicon photodiodes

that are optimized for radiometric accuracy, precision and stability.

During the latter part of FY85, we funded proposals from Advanced Detector

Technology (ADT) in The City of Industry, CA, and United Detector Technology in Hawthorne, CA to investigate innovative processes for producing

stable 100% quantum efficiency silicon photodiodes. The development of

such devices would form the basis for producing substantially improved

100% quantum efficiency radiometers compared to those that can be built

with inversion layer diodes.

Saunders and Houston have also discovered some not yet understood

features in the ultraviolet internal quantum efficiency of some silicon

photodiodes. To our surprise these features do not fit a model of the

effect of the interaction of band gap narrowing and impact ionization in

the depletion region near the oxide interface that we had derived near the beginning of FY85, and for which we had been searching. However, even

though the model cannot explain the experimental results as a coherent

whole, it does predict the location of both features, but this may be a coincidence. Klaus Stock from West Germany's PTB pursued this topic while

a guest worker in the group during FY85, but was not able to shed any more

light on the phenomena during his short stay. He did, however, help us to

develop improved experimental tools for investigating the phenomena

further.

Developments in the germanium spectral region have been disappointing. The Purdue Ge photodiode design was optimized based on the

results obtained last year, and a new diode was fabricated at Purdue and

tested at the University of Arizona. The optimized diode shows no substantial improvement in performance over the previous design. A second

batch was fabricated but was ruined during fabrication, highlighting the

serious difficulties in the fabrication of Ge diodes.

A contract was let with EPITAXX, a new company in Princeton, NJ, for

1 arge-area InGaAs/InP heterostructures as a possible substitute for Ge in

this spectral region, since these devices have the same bandgap as Ge.

One device was delivered and is in the process of being tested. Based on

the long delivery times for incomplete orders, there appear to be

fabrication problems with these devices as well.

89
Division 534, Technical Activities (cont'd)

From Peter Key of the UK NPL, we learned of a very promising Ge

device that was formerly produced by Electro-Optical Systems Specialists

in Berwyn, PA. This device had such a high external quantum efficiency

that it seems its internal quantum efficiency must be nearly unity down to

600 nm, but it exhibited a saturation non-linearity at so low a flux

level that Key and others thought it unsuitable as a standard diode.

Actually, the non-linearity is a symptom of a problem that can probably be

solved without sacrificing high internal quantum efficiency, if ever the

latter is achieved. At our suggestion. Key is in the process of trying to

demount this diode to allow a direct measurement of its internal quantum

efficiency. In the meantime, we are starting discussions with ElectroOptical Systems Specialists about custom radiometric quality diodes.

Turning to a new area of detector research of interest to the Group,

we note that self-calibration may prove a useful tool for the Low

Background, Long Wave Infrared (LBLWIR). Mike Petroff at Rockwell

International in Anaheim recently developed a model of the internal

quantum efficiency of Blocked Impurity Band Infrared Detectors (BIBID)

that operate near liquid-helium temperature in the 5 to 30 urn spectral

region. There are many similarities between intrinsic silicon photodiodes

in the visible and BIBID detectors operating in the LBLWIR, and these

similarities suggest the possibility of self-calibration. Like our silicon self-calibration model in the visible, Petroff's model depends

upon a small number of physically meaningful diode parameters, and the

shape of the relative spectral response determines the absolute value of

the spectral response at every wavelength. This is the key to sel fcal ibration.

To test the feasibility of BIBID self-calibration, we have developed

a non-linear fitting program using a simplex algorithm to adjust the

parameters in Petroff's BIBID model to experimental relative spectral

response data. We expect that the program will determine the absolute

spectral response of a BIBID response values as a function of oxide bias

at a single wavelength. This program will be tested with simulated

spectral response data to determine the optimum set of values for the

wavelength and oxide bias, and the results will be used to design an experimental protocol for an intercomparison between BIBID selfcalibration and a blackbody based calibration. Both the experimental

protocol and the fitting program will be sent to Lum Eisenman at the Naval

Ocean System Command for use in the first intercomparison involving BIBID

sel f-cal ibration.

90
Division 534, Technical Activities (cont'd)

Next year we hope to embark on a program of fundamental research into

BIBID physics as well as to expand our current research into the

fundamental physics of intrinsic silicon photodiodes through the

acquisition of Dr. Jerry Lowney as a new group member. He i s a theoretical /computational solid state physicist with a great deal of

experience in the physics of semiconductor band edges, deep levels, and

the oxide/silicon interface. This experience matches our interests in

BIBID physics, bulk region recombination and interface recombination,

respectively. He also has a fair amount of laboratory experience, and his

forte is modeling and interpreting experimental data.

Spectral Radiometry

In a recent private communication. Fox reported filter transmission

uniformity measurements with the 676.4 nm line of a Krypton ion 1 aser that

are about a factor of five better than those obtained by Schaefer a few

years ago using tunable ring laser radiation. The filter was custom made

by a German firm using wedged glass substrates manufactured in the UK

NPL Optical Shop. The exterior filter surfaces were coated with antireflection coatings. The improved filter uniformity could represent a new state-of-the-art in the development of commercial interference filters, or could be an artifact of the larger line width of the Kr ion laser. Fox

has given one of these filters to Schaefer for measurements to resolve

this question.

Due to staff limitations, little progress has been made on the

Multiple Reflection Configuration Filter or the Michelson Interferometer

Filter. Liang, a WAE employee, has made some progress in developing a more realistic computer model of the Michelson Interferometer Filter, but

he has not been available for this project since May. Schaefer developed

a technique for aligning the Multiple Reflection Configuration Filter and

made some multiple reflection measurements on first surface metal i zed

mirrors to demonstrate the technique. Unfortunately, he could not make

these same measurements on the potential Multiple Reflection Configuration

Filter coating on the laser gyro mirrors that he obtained from OCLI,

because the coated area did not come near enough to the edge of the filter

substrate to support the multiple reflection configuration. Schaefer also

measured the reflectance of the short wavelength band edge of the

potential Multiple Reflection Configuration Filter coating with a single

reflection using dye laser radiation and found that eight reflections

would produce a satisfactory band pass shape.

91
Division 534, Technical Activities (cont'd)

Radiometric Instrumentation

There has been a growing desire within DOD and NASA for our group to

become the Government's "in-house" center of expertise for photodiode

measurement and calibration technology. To take on this role requires

that we expand the scope of our interests in certain directions, while

restricting the scope in other directions. We must start to consider how

to achieve high accuracy and precision at very low flux levels as well as

at the moderate levels that were our only concern previously, and we must

consider new spectral ranges. As a consequence of this new focus, we

will probably have to leave the development of spectral analyzers that

are optimized for use with self-calibrated detectors to other groups, due

to a lack of resources.

To implement the group's changing role, we have first to achieve the

current state of the art in a number of detector technologies and build

new characterization facilities to test the level of precision and

accuracy available from these technologies.

In this connection, Schaefer and Tobin are assembling an ultra-high

precision radiometer characterization facility that is designed to study

the stability of radiometers at the parts per million level over periods

from seconds to weeks. Schaefer is also acquiring the current state-ofthe-art of measurements at liquid nitrogen temperature, and is designing

an apparatus with which to carry out precision studies as a function of

temperature based upon commercial Joul e-Thompson micro- miniature

ref ri gerators.

Schaefer is also collaborating with Dr. A. Young of San Diego State

University and Dr. W. Borucki of NASA Ames Lab, to develop a prototype

stellar radiometer which will be used to improve the state of the art of

relative steller brightness determinations, and to search for extra solar

planetary systems.

In the same connection, Fowler is planning a facility for electronic

characterization of diodes, array elements and amplifiers. The purpose of

this facility will be to support accurate measurements of current vs. voltage (IV), capacitance vs. voltage (CV), noise, and electronic gain of

radiometric devices, for correlation of these characteristics with device

performance.

Fowler and Tobin are also in the process of setting up an apparatus

for dynamic linearity measurements on detectors under simulated waveforms. This instrument is based upon our earlier experience with this

type of measurement in support of the NASA Langley Research Center's

Differential Absorption LIDAR (DIAL) program.

92
Division 534, Technical Activities (cont'd)

Water Bath B1 ackbody

During FY85, Fowler designed and constructed a water bath black body

for the 5 to 60 degree temperature range. It is based on a circulating

water bath and incorporates computer control and a level of selfcalibration capability. Fowler modified the bath by moving the

ref rigeration coils closer to the heater for better temperature control,

and by mounting a 4 inch diameter, black body cavity in the wall of the

bath.

The bath is controlled by the circuitry provided by the manuf acturer

,

but the temperature of the bath is measured by a high accuracy thermistor

under computer control. The user inputs the desired control temperature,

and an acceptable temperature tolerance range to the bath. Whenever the

bath temperature drifts out of the tolerance range, the computer changes

the set point in the bath control circuitry. This effectively increases

the long term stability of the bath well beyond what was available from

the commercial product. The computer also records whether or not the bath

temperature is within tolerance at any given time on the RS-232 port, and

records the periods when it is out of tolerance and the maximum deviation

during each period on a disk file.

The system is calibrated in SI thermodynamic temperature units by

removing the thermistor from the bath, placing it in small freezing point

cells that are provided with the system, and recording the voltage drop across the thermistor during a freeze. One of the freezing point cells

contains ice water, and the other two are available from NBS as Standard

Reference Materials. When calibrated in this way the thermistor is

capable of temperature measurements that are accurate to within 2 mK over

the 0 to 6U°C range. However, other sources of error, such as the

temperature uniformity of the water around the black body cavity, will

limit the current version of water bath to somewhere between 10 and 30 mK

accuracy. In closing, we note that we may not be able to carry out work

of this nature in the future due to our expanded role in photodiode

physics.

93
Division 534, Technical Activities (cont'd)

RADIOMETRIC MEASUREMENT SERVICES (D. A. McSparron)

This Group provides a firm measurment base for the Nation's optical

radiation community (defense and aerospace, instrument manufacturers and

commercial calibration laboratories, lighting and photographic industries,

research institutions, etc.). To accomplish this objective, the Group:

(1) Maintains measurement scales and provides, improves and extends NBS

calibration services for the basic pyrometric, radiometric, and

photometric quantities: radiance temperature, spectral radiance,

spectral irradiance, detector spectral responsi vity , luminous

intensity, luminous flux, and color temperature.

(2) Engages in activities such as intercomparisons, measurement assurance

programs, intermediate laboratory support programs, consultations and

ad hoc experiments that will insure that measurments made in

laboratories outside NBS have acceptable levels of accuracy.

The continuing effects of the failure of the NBS high-accuracy

photoelectric pyrometer have dominated the calibration activities of the

Group. The interim procedures instituted last year to allow calibration

of pyrometric strips lamps on FASCAL have been refined by Walker to

improve efficiency, although pyrometric calibrations continue to occupy

about 25% of the available time. Direct public calibration billings for

pyrometry, spectroradiometry , and photometry increased by about 25%.

Again this year, Jackson performed a substantial amount of spectral

irradiance calibration work in support of NASA/NOAA solar monitoring

programs, notably the Solar Backscatter Ultra Violet (SBUV) Radiometer

program. This other-agency calibration work also shows an increase of

about 25% in comparison to FY 1984.

At the 1982 meeting of the Consultative Committee on Photometry and

Radiometry (CCPR) plans were formulated for an international

i ntercompari son of the photometric units of luminous intensity and

luminous flux. These intercomparisons are of particular interest, since

they will be the first attempt to evaluate quantitatively the effects of

the recent redefinition of the photometric units. During the current

year, NBS completed the initial measurments on the intercomparison lamps

and submitted them to the International Bureau of Weights and Measures.

In FY-86 the lamps will be returned to NBS for remeasurement and it is

expected that result will be available in the summer of 1986.

Significant progress was made in the filter radiometry project to

realize photometric scales by means of absolute silicon detectors and

interference filters. Mr. Bruening worked at the Egyptian Standards

Laboratory (NIS) for a month completing the joint effort that brought

94
Division 534, Technical Activities (cont'd)

Egyptian scientists to NBS the previous year. While in Egypt,

measurements necessary for realizing photometric scales were performed

with an accuracy of +4%, -2% in the center of the visible. This

demonstration completed the joint project with NIS. The work at NBS was

continued with the spectral calibration of an incandescent lamp. The

agreement with the bl ackbody-based scale was at the ±2% level. In the

process of characterizing the commercial detectors used in this work,

several areas for improvement were noted. These suggestions were passed

on to the manufacturer and have resulted in changes in the production

process.

The intermediate laboratory support program for geometrical ly-total

spectral flux is now well underway. The goal of this program is to

develop a sustained source of photometric standards with rapid

accessibility. The program was initiated in response to the Fourth CORM

Report and is being coordinated with the Lamp Testing Engineers Conference

(LTEC). One or more commercial laboratories will maintain close ties with

NBS through measurement i ntercompari sons and will undertake to generate

standards for lamp types not normally available from NBS. Validation of

measurement capability for spectrally rich sources will require the NBS

supply incandescent and one non-i ncandescent , standards of spectral flux.

Ward was assigned full time to the incandescent phase of this project in

January, and has completed the rebuilding of the gonio-spectroradiometer

;

procurement, modification, and seasoning of suitable lamps; and is well

along towards the full characterizat ion of the instrument. It is

projected that lamps will be available for issuance to the industry in

December, 1985. The second year work of the project, on high pressure

sodium lamps, is well ahead of schedule thanks to the efforts of He MingGao, a guest scientist from Fudan University, Shanghai, China, and Joseph

Kepple, a summer student from Butler College. Appropriate ac electrical

circuitry for operating the lamps has been setup and checked out, a lamp

seasoning rack has been constructed, and the check out of a spectroradi o- meter has begun. The completion of the total project by the end of FY-86

seem wel 1 i n hand.

Mr. Ohno, a guest scientist from Matsushita Electric Industrial

Company, Osaka, Japan, has made substantial progress in his project to

explore alternatives to goniometry for generating geometrical ly-total flux

standards. The concept of using a small integrating sphere whose

throughput has been spectrally characterized and which is calibrated with

an external source has been explored in a computer modeling study. The

results of this modeling study indicate that an accuracy of a few tenths

of a percent may be achievable with this approach. An experimental

program to verify these very encouraging results has begun and is expected

to be completed in the first quarter of FY-86.

95
SPONSORED CONFERENCES

Division 534, Radiometric Physics

Thirty-third National Infrared Information Symposium, May 14-16, NBS,

Gaithersburg, MD

Council for Optical Radiation Measurements, NBS, Gaithersburg, MD, May

29-30, 1985.

96
INVITED TALKS

Division 534, Radiometric Physics

J. Geist, "Silicon Photodiode Physics as a Basis for Accurate

Radiometry", Invited Lecture Tour of People's Republic of China, State

Bureau of Metrology - Chengdu and Shanghai, April 10 - April 28, 1985.

J. Geist, "Historical Introduction to Radiometry", and "Modern Electooptical Technology and Radiometry", Invited Lecture Tour of People's

Republic of China, State Bureau of Metrology - Beijing, April 11-12,

1985.

J. Geist, "Silicon Photodiode Physics as a Basis for Accurate

Radiometry", Tranducers '85, 1985 International Conference on Solid-State

Sensors and Actuators, Philadelphia, PA, June 11-14, 1985.

J. Geist, "Physics of Silicon Photodiode Self-Calibration", and

"Conference Summary", International Meeting on Advances in Absolute

Radiometry", and "Conference Summary", Cambridge, Mass., June 24-25,

1985.

J. J. Hsia, "Bidirectional Reflectance Distribution Function (BRDF

)

Measurement Methods - An Overview of Go nio-spectrophotometry" , Invited

Lecture Tour of People's Republic of China, State Bureau of Metrology - Beijng, Chengdu, and Shanghai, April 1U - April 28, 1985.

J. J. Hsia, "Philosophy and Establishment of U.S. National Scales in

Spectrophotometry" , Invited Lecture Tour of People's Republic of China,

State Bureau of Metrology - Beijng, Chengdu, and Shanghai, April 10 - April 28, 1985.

J. J. Hsia, "NBS Standard Reference Materials in Spectrophotometry and

Densitometry", Invited Lecture Tour of People's Republic of China, State

Bureau of Metrology - Beijng, Chengdu, and Shanghai, April 10 - April 28,

1985.

J. J. Hsia, "Current Technical Activities on Spectrophotometry in the

U.S. Standard Organizations and Societies (ASTM, ISCC, ANSI)", Invited

Lecture Tour of People's Republic of China, State Bureau of Metrology - Beijng, Chengdu, and Shanghai, April 10 - April 28, 1985.

J. J. Hsia, "Current Technical Activities on Spectrophotometry in the

International CIE Standard Organization", Invited Lecture Tour of

People's Republic of China, State Bureau of Metrology - Beijng, Chengdu,

and Shanghai, April 10 - April 28, 1985.

A. R. Schaefer, "Development of Quantum-Perfect Detectors", Space Science

Division Astrophysics Seminar Services, NASA Ames Research Center, August

13, 1985.

97
Division 534, Invited Talks (cont's)

E. F. Zalewski, "Implementation of the Silicon Photodiode Sel fCalibration Procedure", Atmospheric and Environmental Research, Inc.,

Cambridge, Massachusetts, June 24, 1985.

E. F. Zalewski, "Radiometry ' s Holy Grail: 100% Quantum Efficient

Detectors", Optical Society of America, Local Chapter, Washington, DC,

April 17, 1985.

98
PUBLICATIONS

Division 534, Radiometric Physics

Eckerle, K. L. , Hsia, J.J. and Weidner, V. R., Transmittance MAP Service,

NBS Spec. Pub. No. 692, 1-44 (March, 1985).

Eckerle, K. L. , Chang, S. and Hsia, J.J., Calibration in 1976 and 1983 of

Didymium Glass Filters Issued as NBS Standard Reference Materials, Color

Res. Appl . U)_ (1 ), 32-37 (Spring 1985).

Hattenburg, A. T. , and Shumaker, J. B., Linearity Study of a Diode Array

Radiometer, Applied Optics Letter, 23_, 3257 (1984)

Keller, R. A., Warner, B.E., Zalewski, E.F., Dyer, P., Engleman, R. Jr.,

and Palmer, B.A., The Mechanism of the Optogalvanic Effect in a HollowCathode Discharge, J. de Physique, 44, C7-23, (1983).

Lowney, J. R., and Geist, J. , Comparison of Models of the built-in

Electric Filed in Silicon at High Donor Densities, J. Appl. Phys. _55_, 3624-3627 (1984).

Popenoe, C. H., and Hsia, J. J., Optical Density Determination with an Inverse-Fourth Instrument (Technical Activities 1984, NBSIR 84-2944,

November 1984).

Richmond, J. C. and Nicodemus, F. E. , Self-study Manual on Optical

Radiation Measurements Part I--Concepts, Chapter 12, Blackbodies,

Blackbody Radiation, and Temperature Scales, NBS Technical Note 910-8,

April 1985.

Saunders, R. D. and Shumaker, J. B., An Automated Radiometric Linearity

Tester, Applied Optics, Vol. 23, 3504, October 15, 1984.

Schaefer, A. R., Photodiodes for Astronomical Stellar Radiometry, Proc. of

the Workshop on Improvements to Photometery, NASA Conference Publication

2350, November 1984.

Schaefer, A. R. , Saunders, R. D. , and Hughey, L. R. , Intercompariso

n

Between Independent Irradiance Scales Based On Silicon Photodiode Physics,

Gold Point Blackbody Radiation, and Synchrotron Radiation, Proc. SPIE 499,

15-23 (Fall 1984).

Weidner, V. R. , Hsia, J. J., and Adams, B., Laboratory Intercomparison

Study of Pressed Po lytetrafl uorethyl ene (PTFE) Powder Reflectance

Standards, Applied Optics, 24_ (14), 2225-2230 (July 1 5, 1985).

99
Division 534, Publications (cont'd)

Weidner, V. R., Mavrodi neanu , R. , Mielenz, K. D. , Velapoldi, R. A.,

Eckerle, K. L. , and Adams, B., Spectral Transmittance Characteristics of

Holmium Oxide in Perchloric Acid Solution, NBS Journal of Research, 90_

(2), 115-125 (March - April, 1985).

Wilkinson, F. J., Farmer, A.J.D., and Geist, J., The Near Ultraviolet

Quantum Yield of Silicon, J. Appl. Phys. 54_, 1172-1174 (February, 1983).

Zalewski, E.F., and Gladden, W.K. Absolute Spectral Irradiance

Measurements Based on the Predicted Quantum Efficiency of a Silicon

Photodiode, Opt. Pura Y Aplicada, _17_, 133 (1984).

100
PUBLICATIONS IN PREPARATION

Division 534, Radiometric Physics

Dils, R. R., Geist, J., and Reilly, M., Measurement of the Silver

Freezing Point with an Optical Fiber Thermometer: Proof of Concept,

Journal of Applied Physics, (in press).

Geist, J., On the Possibility of Self-calibration of Blocked Impurity Band

Detectors in the Low Background Long Wave Infrared.

101
TECHNICAL AND PROFESSIONAL COMMITTEE PARTICIPATION AND LEADERSHIP

Division 534, Radiometric Physics

Robert L. Booker

Member, U.S. Panel of CIE TC-2.06 on Absolute Spectral Responsi vity

.

Member, U.S. National Committee of the CIE.

Julius Cohen

Member, ASTM E-07 Committee on Nondestructive Testing, Section

E-07. 10.04 on Infrared Methods.

Kenneth L. Eckerle

Member, ASTM E-13 Committee on Molecular Spectroscopy, Subcommittee

E-13.03 on Infrared Spectroscopy, Subcommittee E-13. 01 on Ultraviolet

and Visible Spectroscopy, Subcommittee E-13. 06 on Luminescence.

Jon C. Geist

Member IMEKO 10002 on Photon Detectors.

Jack J. Hsia

Associate Director, CIE Division 2 on Physical Measurement of Light

and Radiation.

NBS representative, ANSI PH2 on Photographic Sensitometry and PH2-28

on Densitometry.

Member, ASTM D- 1 .26 Subcommittee on Optical Properties of Paint,

Varnish, Lacquer and Related Products.

Member, ASTM E-12 Committee on Appearance of Materials

(Spectrophotometry, colorimetry and geometric properties).

Member, ASTM E-13 Committee on Molecular Spectroscopy, Subcommittee

E-13. 01 on Ultraviolet and Visible Spectroscopy, E-13.03 on Infrared

Spectroscopy, and E-13. 06 on Molecular Luminescence.

Member, ASTM E-07. 03 Task Group for Fluorescent Penetrant Measurement

Standards.

102
Division 534, Technical and Professional Committee Participation and

Leadership (cont'd)

Jack J. Hsia (Cont'd)

Member, ASTM E-13 Committee on Molecular Spectroscopy Subcommittee

E-13.01 on Ultraviolet and Visible Spectroscopy, E-13. 03 on Infrared

Spectroscopy, and E-13. 06 on Molecular Luminescence.

Member, ASTM E-07.03 Task Group for Fluorescent Penetrant Measurement

Standards.

Secretary, CORM/NBS Task Force on Spectrophotometry

.

Secretary, National Capital Section of the Optical Society of

Ameri ca.

Donald A. McSparron

Consultant, CIE Technical Division II on Physical Measurement of

Li ght and Radi at ion.

Member, ANSI Z311 on Photobiological Safety of Lamps.

Member, Illuminating Engineering Society (IES), Testing Procedures

Committee.

Member, Lamp Testing Engineers' Conference.

Member, Infrared Calibration Standards Committee.

Klaus D. Mielenz

Secretary, U.S. National Committee of the CIE.

Secretary, CIE Division 2.

Member, ASTM E-13 Committee on Molecular Spectroscopy, Subcommittee

E-13. 06 on Molecular Luminescence.

Vice Chairman, CORM, TASK Force on Spectrophotometry.

Member, IES Committee on Nomenclature.

Robert D. Saunders, Jr.

Member, ANSI Z311 on Photobiological Safety of Lamps and Lighting

Systems.

103
Division 534, Technical and Professional Committee Participation and

Leadership (cont'd)

Robert D. Saunders, Jr. (Cont'd)

Member, IES Committee of Photobiology.

Douglas B. Thomas

Member, ASTM Committee E44 on Solar Energy Conversion.

William R. Waters

Member, ASTM Committee E-20 on Temperature Measurement.

Edward F. Zalewski

Member, CIE Committee Div. 02 on Physical Measurement of Light and

Radi at ion.

Member, U. S. National Committee of the CIE.

104
STANDARDS COMMITTEE MEETINGS

Division 534, Radiometric Physics

Illuminating Engineering Society, Testing Procedures Committee, Spring

Meeting, April 11-12, 1985, NBS, Gaithersburg, MD

Lamp Testing Engineers Conference, Spring Meeting, April 10, 1985, NBS,

Gaithersburg, MD

ASTM, Radiation Thermometry, Commitee E-20, NBS, May 30-31, 1985

105
STANDARDS WRITING

Division 534, Radiometric Physics

J. Cohen, Minimum Resolvable Temperature Difference for Thermal Imaging,

ASTM E-U7.10.04 on Infrared methods (Draft, April 1985).

106
MAJOR CONSULTING AND ADVISORY SERVICES

Division 534, Radiometric Physics

J. Cohen provided consultation to Dag Holmsten of AGEMA, NJ and Harry

Berger, Consultant, MD on thermal imaging and temperature profile.

J. Geist provided consultation to representatives of the U.S. Department

of Energy on two proposals for novel temperature measurement techniques.

J. Geist provided consultation to representatives of the U.S. Aluminium

Institute on a proposal for a novel temperature measurement technqiue.

J. Geist provided consultation to Rich Hansen of FIBREX Corporation on

the optical design of high emittance refractory materials.

J. Geist provided consultation to Raj Khorde of United Detector

Technology on the design of high quantum efficiency silicon photodiodes.

J. J. Hsia provided consultation to William M. Hell of NASA (Langley) on

the flux averaging devices in the infrared spectral region.

J. J. Hsia provided consultation to Michael L. Rudolph (Rochester),

Richard J. Byer (Rochester), and John C. Cloya (Wilmington) of DuPont on instrumentation and calibration of optical densities.

J. J. Hsia provided consultation to Mike Goodwin of Eastman Kodak on

optical density of spectrophotometric measurements.

J. J. Hsia provided consultation to Sergei Jacobson of Israeli Air Craft

Industries Co. on developing diffuse ref 1 ectometer.

D. A. McSparron served as a consultant to the Growth Chambers and

Controlled Environments Working Group of the American Society for

Hort icul tural Science on optical radiation measurements in plant growth

chambers.

D. A. McSparron reviewed the "proofs of competency in photometric

measurements" offered by the contractor to the University of Petroleum

and Minerals, Dharan, Saudi Arabia, and advised UPM as to their adequacy

and completeness.

A. R. Schaefer provided consultation to W. Boruchi of NASA Ames Research

Center on the Design of multi-channel radiometers for extra solar

planatory detection.

107
Division 534, (Major Consulting and Advisory Services cont'd)

A. R. Schaefer provided consultation to Nigel Fox of the UK National

Physical Laboratory on the use of ring dye lasers for accurate

radiomet ry

.

V. R. Weidner and J. J. Hsia provided consultation to Keith Snail of NRL,

Washington D.C. and Herb Tardy of Sandia Laboratory on long wavelength

infrared refl ectometer instrumentation.

V. R. Weidner provided consultation to Richard S. Bodanes of NIH on

absorptance measurements of hemato-porphyri n derivative (HPU), a complex

mixture of photosensitizing porphyrins which is selectively retained in

tumor tissue and used in cancer photochemotherapy.

E. F. Zalewski and D. A. McSparron advised the Office of Product

Standards Policy on an appropriate U.S. position on a draft OIML

specification for optical pyrometers.

108
STANDARD REFERENCE MATERIALS

Division 534, Radiometric Physics

1. SRM 1001, X-Ray Film Step Tablet

Used in the calibration of optical densitometers and similar

equipment used in the photographic, graphic arts, and x-ray fields.

Certified for Optical Densities from 0 to 4.

2. SRM 1008, Photographic Step Tablets

Used in the calibration of optical densitometers and similar

equipment used in the photographic and graphic arts fields.

Certified for Optical Densities from 0 to 4.

3. SRM 1010a, Microcopy Resolution Tests Charts

Used for determining the resolving power of microcopy systems.

4. SRM 2061 , Reflection Step Tablets

Used in the calibration of reflection densitometers and similar

equipment used in the photographic and graphic arts fields.

Certified for optical density from 0 to 2.

5. SRM 2019 and 2020, White Ceramic Tile for Di rectional -Hemi spherical

Reflectance from 250 to 2500 nm. SRM 2021 and 2022, Black Porcelain Enamel for DirectionalHemispherical Reflectance from 250 to 2500 nm. SRM 2015 and 2016, White Opal Glass for Di rectional -Hemi spheri ca

1

Reflectance from 400 to 750 nm.

For use in calibrating the reflectance scale of an integrating sphere

refl ectometer.

6. SRM 2003b, First Surface Aluminum Mirror for Specular Reflectance

from 250 to 2500 nm. SRM 2011, First Surface Gold Mirror for Specular Reflectance from 600

to 2500 nm. SRM 2023, 2024, and 2025 Second Surface Aluminum Mirror for Specular

Reflectance from 250 to 2500 nm.

For use in calibrating the photometric scale of specular

refl ectometers.

7. SRM 2009, 2010, 2013, 2014 Di dymi um-Oxi de glass as Wavelength

Standards between 400 and 760 nm.

109
Division 534, Standard Reference Material (cont'd)

8. SRM 2034 Holmium oxide in Perchloric Acid Solution as Wavelength

Standards between 241 and 640 nm.

no
MEASUREMENT ASSURANCE SERVICES

Division 534, Radiometric Physics

1. Transmittance MAP Service

Provides a means for a laboratory to assess the accuracy of its

spectral transmittance measurement capabilities from 92% to 0.1% in

the visible region.

2. Retrorefl ectance MAP Service for Coefficient of Luminous Intensity

Provides a means for a laboratory to assess the accuracy of its

coefficient of luminous intensity measurement capabilities for bead

sheeting and prismatic cube-corner retrorefl ectors and to assess the

conformity to the spectral specification of its retrorefl ectometers.

Ill
CALIBRATION SERVICES PERFORMED

Division 534, Radiometric Physics

Type of Service Customer SP250

Number of

test I ncome

Pyrometry 7.4 A 32 $50K

thru G

Spectroradiomet ry

Photo met ry

Spectrophotometry

Defense & Aerospace 9 $20K

Instrument & Cal 1 abs 8 1 IK

Lighting & Photography 5 6K

Electrical & Materials 10 13K

7.5 A 38

thru J

Defense & Aerospace 18 32 K Instrument & Cal 1 abs 7 10K

Lighting & Photography 2 6K

Foreign 6 13K

Electrical & Materials 5 9K

7.7A 12

thru R

Defense & Aerospace 4 16K

Instrument & Cal 1 abs 4 8K

Foreign 2 3K

Electrical & Materials 2 3K

7.8 A 29

thru I

Defense & Aerospace 3 2K

Instrument & Cal 1 abs 10 6K

Lighting & Photography 3 2K

Foreign 2 2K

Electrical & Materials 11 10K

70K

30K

22K

111 172

112
TRIPS SPONSORED BY OTHERS

J. C. Geist, Lecture Tour of the People's Republic of China, sponsored by

Protocol Agreement between NBS and Chinese State Bureau of Metrology,

National Institute of Metrology, Beijing; Institute of Measurement and

Test Laboratories, Chengdu, Sichun Province; Shanghai Bureau of

Metrology, Shanghai.

J. J. Hsia, Lecture Tour of the People's Republic of China, sponsored by

Protocol Agreement between NBS and Chinese State Bureau of Metrology,

National Institute of Metrology, Beijing; Institute of Measurement and

Test Laboratories, Chengdu, Sichun Province; Shanghai Bureau of

Metrology, Shanghai.

K. D. Mielenz, to represent the U.S. National Committee of the CIE at

Executive Committee Meetings, sponsored by the Unites States National

Committee of the Commission Internationale De L'Eclairage (CIE).

113
SPONSORED SEMINARS AND COLLOQUIA

Division 534, Radiometric Physics

Dr. Fritz Riehle, “Recent Advances in Radiometry at BESSY", July 24, 1985,

(Sponsored jointly with Division 533).

114
TECHNICAL ACTIVITIES

Division 535, Radiation Source and Instrumentation

Task No. 15252 - Provide linac beam

Task No. 15253 - FASTBUS instrumentation specification

Task No. 15254 - Design, install and test microtron components

CW Accelerator Research (Microtron)

The NBS-Los Alamos joint project of "Research on CW Electron Accelerators Using Room-Temperature RF Structures" was started six years ago,

with the goal of developing a technology base for CW electron accelerators. Many significant technical advances have been made as a part of

this project, which is funded by DOE. Some of these, including the chopper/buncher system, side-coupled RF structures, end magnets, and beam profile scanners, have been recognized by the accelerator community by being

copied or adapted for use in other accelerator systems. We presented

eight papers describing our recent work on the racetrack microtron (RTM)

at the Particle Accelerator Conference at Vancouver, B.C. in May 1985.

When the RTM is operating, it is expected to have many unique performance characteri sties including the CW nature of the beam, the high

current (up to 700 uA, consistent with maximum beam power of 100 kW),

easily variable energy over a very wide range (~15 to ~220 MeV), excellent

emittance, and very small energy spread (<4 parts in 104 at 185 MeV).

These characteristics make the RTM a very valuable resource for a number

of future research uses. Under present funding allocations we are estimating that construction of the RTM will be completed in June 1987. Following a period of accelerator physics research with the completed machine,

it will be available for other research in late 1987.

In this report, we describe in detail the technical accomplishments

of the project in FY 1985. It has been a highly productive and successful

year. Highlights include: measurement of the 100 keV chopped beam emittance, which exceeds specifications; completion of installation of the

entire 5 MeV injector linac system, with all RF power and drive; extensive

field mapping of one end magnet, whose performance is excellent - far

exceeding specifications; completion of construction of the 12 MeV linac

for the microtron; installation of most of the control system, including

the primary station; and first acceleration of beam by the injector

1 i nac.

An overall view of the RTM is shown in figure 1. The installation is

complete with exception of: Phase II of the 5 MeV injection transport

system; the 12 MeV linac and main axis beam line components; end-magnet

vacuum chambers; recircul ation return beam lines; and the extraction beam

line.

115
116

J\l

Figure

1

Pl

an

view

of

the

RIM
Division 535, CW Accelerator Research (Microtron) (cont'd.)

A. Injector

1. Introduction

The injector consists of an electron gun in a 100 kV terminal, a 100

keV beam transport line, a 5 MeV injector linac, and a 5 MeV beam transport line. In FY 1985, the transverse emittance of the chopped 100 keV

beam was measured and found to be consistent with the design value. The

injector linac was used in tests of the RF system performance at Los

Alamos. It was then moved to NBS, where it was installed, aligned, and

put under vacuum with the 100 keV beam line. The injector stage of the RF

system was assembled at NBS and tested with the injector linac. The first

phase of the 5 MeV beam line (viz., the part required for injector linac

performance tests) was installed, aligned, and put under vacuum. The

control system was expanded to accommodate the injector linac, the injector RF system, and the first phase of the 5 MeV beam line. We have accelerated beam through the injector linac and measured its energy in the 5 MeV beam line.

2. 100 keV Beam Emittance Measurements

Measurements of the transverse emittance of the beam were made using

three wirescanners temporarily located at the exit of the 100 keV beam

line. The design value of emittance at this point is 5*it mm-mrad. The

results of the measurements are summarized in figure 2. The emittance of

the dc beam is seen to be about 2n mm-mrad from 0 to 600 uA. This is well

below the 4u mm-mrad limit imposed by the defining apertures and is a measure of the electron gun emittance plus the effects of any aberrations

in the 100 keV beam line.

Chopping the beam increases the measured emittance by a factor which

shows no systematic dependence on beam current. This is probably due to

the sensitivity of emittance on tuning the second RF deflection cavity for

exact cancellation of the transverse momentum imparted to the beam by the

first cavity. The chopped beam emittance is lowest (3ir mm-mrad) for the

beam current (300 uA) for which we have the most experience in tuning, so we expect the emittance at other currents to decrease with more operational experience. In any event, the measured chopped beam emittance was below the 5rr mm-mrad design value at all beam currents but one.

The magnetic shielding around the electron gun and the 100 keV beam

line was designed to reduce stray magnetic fields to a negligible level on the beam axis. The effectiveness of the shielding was tested by looking

for deflection of the 100 keV beam when end magnet El was energized. No

deflection was observed, which indicates correct performance of the

shielding.

117
Figure 2 100 keV transverse beam emittance. Dots

represent resul ts of measurements on dc beam.

Open circles represent chopped beam. Triangles represent chopped and bunched beam.

Error bars denote statistical spread in re- peated measurements.

118
Division 535, CW Accelerator Research (Microtron) (cont'd.)

3. 5 MeV Beam Line Phase I

Phase I of the 5 MeV beam transport line will be used for performance

tests of the injector linac. As shown in figure 3, it consists of a straight section for measuring the transverse emittance of the 5 MeV beam

and a 45° bend for measuring the energy spread. This beam line has been

installed, aligned, put under vacuum, and connected to the control system.

It is in use for injector linac beam tests.

A design goal for all bending magnets in the 5 MeV transport line is

to keep the ratio of sextupole to dipole components below 7 x 10 _4 cnr 2

. The design calculations for the two identical 45° bending magnets D1 and

D2 were consistent with this requirement. Using our recently developed

small magnet mapper, described in section E6 of this report, we measured

the magnetic field of magnet D1 . The measured relative sextupole component is 9 x 10 _5 cm~2 in the uniform field region, and is 4 x 10~4 cm~ 2 integrated over the full length of the magnet. The largest contribution

is from the field clamps. The measurements also showed excellent agreement with the calculated shape of the fringe field. The measured effective boundary of the fringe field is within 0.5 mm of the calculated location.

Magnets Q1 and Q2 are prototypes of quadruples that will be used

throughout the RTM. Good quadrupole field purity is required at relatively low field strength. Q1 and Q2 were fabricated of excess 1006 steel

from the end magnets to determine if this requirement can be met using

this material. Machining was done carefully in the MBS Shop to preserve

the annealed condition of the steel as much as possible. Tight dimensional tolerances were achieved in construction. Preliminary field measurements show that the quadrupole purity is approximately 99%, which meets

our requirements.

4. 5 MeV Beam Line Phase II

Following performance tests of the injector linac, phase II of the 5 MeV beam line will be constructed to transport 5 MeV beam to the microtron

as shown in figure 4. Magnets for this beam line are in the design stage.

The 30° bending magnets D4 and D5 are symmetric elements of an achromatic

60° bend and as such must be as close as possible to identical. Their

width is tightly constrained by the proximity of D5 to D9 . 04 and D5 were originally conceived as having air-cooled coils of solid conductor. Model

tests done in the past year indicated that the coil temperature could

exceed 100°C with only convective cooling. We have decided to use a different design, shown in figure 5, with hollow, water-cooled conductor. By

distributing the extra vertical space throughout the coil as shown, the

calculated magnet field uniformity is acceptable, with a sextupole component of 5 x 10~4 cnr2

.

119
120

Figure

3

plan

view

of

Phase

I

injector

transport.

The

elements

labelled

"S"

are

steering

dipoles.

M2

is

an

RF

beam

monitor

package.

"W&

V"

denotes

wirescanner

and

viewscreen

assemblies.
Q i a 2 Dt

a? G6 DS D 9 D 10

Figure 4 Schematic of injection transport line.

This figure is a mirror image of the

actual layout.

121
122

Figure

5

Cross

section

of

the

30°

bending

magnets

for

the

5

MeV

beam

1

ine

with

vacuum

chamber.
Division 535, CW Accelerator Research (Microtron) (cont'd.)

B. Microtron

1. Introduction

The microtron consists of a 12 MeV linac, two end magnets, beam lines

to recirculate the beam through the linac, and a beam line to extract the

beam and measure its properties. In the past year the second of two 4 m

long accelerating structures which comprise the 12 MeV linac was com- pleted, and the second end magnet was delivered and installed. Following

modification of both end magnets to reduce deflection of the poles during

operation, the field of one end magnet was completely mapped and was found

to exceed specifications with no trimming. The second end magnet is

scheduled for mapping by the end of the fiscal year. The microtron design

has been simplified significantly by modifying the design of the injection

chicane magnets to include compensation for the effect of the reversing

magnets on every orbit. This eliminates the 26 compensation magnets which were to be located on the return lines. Finally, a simplification was made to the extraction line design.

2. End Magnets

The end magnets were designed to generate a uniform field, B, in the

operating range 0.8 T to 1.2 T with a field uniformity such that the average fields along each of the first 14 orbits differ by no more than

±2 x 10"4 B. During the past year the second end magnet was delivered and

reassembled on its support stand. Both magnets were accepted from the

vendor following successful completion of final coil tests (electric and

hydraulic) and dimensional inspection. Meanwhile, the field mapping

apparatus was brought into full operation with automatic probe positioning, data taking, and data storage.

Preliminary mapping of the first magnet showed an unexpected and

unacceptable field inhomogeneity at the front. We then removed the reversing poles and yokes and observed that as the magnet was energized, the

air gap dimension decreased in the vicinity of the inhomogeneity. The

problem was that the main yoke was unexpectedly yielding under the magnetic force in the front center of the magnet, and its deflection was being

transmitted to the poles by the nonmagnetic shims located between the yoke

and the poles. This problem was cured by removing a thickness of material

equal to the observed decrease in the air gap symmetrical ly from the top

and bottom nonmagnetic shims. Subsequent measurements confirmed that the

gap dimension now remains well within tolerance over the operating field

range of 0.8 to 1.2 T.

With the gap constriction problem eliminated in the first end magnet,

a complete field map was taken. The results are shown in figure 6 for the

uniform field region. The variation in the orbi t-averaged field at 1.0 T

123
X (CM)

z

(CM)

20 —

T—

40 60 80 100 120 140

Figure 6 Contour plots of the measured quantity ( aB/B

q )x 10 4 on the

magnetic midplane in the air gap. From top to bottom, B

0 is 0.8, 1.0, and 1.2T. Negative contours are shown as broken lines. The field measurements were taken on a 4x4 cm grid for z < -12 cm and a az = 1 cm, ax = 4 cm grid for

z > -12 cm. On the 1 T field plot, four of the electron

orbits are shown.
Division 535, CW Accelerator Research (Microtron) (cont'd.)

is ±4 x 1 0~ 5

, a factor of five more uniform than required. At 0.8 T, the

uniformity is even better, and at 1.2 T, the uniformity still exceeds the

requirement by a factor of two. The measured fringe field shape is indistinguishable from the design calculations and is virtually identical for

every orbit.

The second end magnet has also been modified so that the gap dimension is within tolerance over the operating field range. It is scheduled

for mapping in September 1985 and we expect the results to be as good as for the first magnet.

Three dc power supplies will be used to power the end magnets in

operation. A 1500 A, 250 kW supply with 10~ 5 current regulation will

power the main coils of both end magnets in series. A small trim supply

will power auxiliary windings on both magnets in series with opposed

polarities to cancel residual field differences between the magnets. A

dual -channel , 300 A supply with 10'4 current regulation will power the

active field clamp coils of the two magnets independently.

The main supply and both channels of the 300 A supply have passed

preliminary acceptance tests following delivery. For these tests the

supplies were operated into resistive loads at full power. The current

regulation, stability, and ripple were within specifications. Both supplies were then used to power the end magnets individually and performed

satisfactorily with the exception that one channel of the 300 A supply has

gone out of its stability tolerance. Following repair of the dual channel

supply and mapping of the second magnet, the supplies will be connected to

both magnets and final acceptance tests will be performed. The field

difference between magnets will then be measured, and an appropri ately

rated, commercially available trim supply will be purchased.

3. Microtron Design

In the microtron, every return orbit 2-14 is translated toward the

inside of the microtron by the reversing magnets D8 and D7. The translation must be compensated to prevent the returning beam from entering the

accelerator off-axis. In the original design, two compensating magnets

were used on each return line 2-14, a total of 26 magnets. In the past

year we have decided to include the compensation function in magnets D9

and D10 in the injection chicane. This eliminates the 26 individual com- pensating magnets and simplifies the microtron design.

The design of magnet D9 has been modified as shown in figure 7 to

provide compensation for the reversing magnets. The solid-conductor coil

of D9 will be powered in series with the coil of D6, with the current in

these coils adjusted for correct injection of 5 MeV beam by D6. The

water-cooled coil in D9 will be powered in series with the coil in D10 to

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Division 535, CW Accelerator Research (Microtron) (cont'd.)

translate the orbits toward the outside of the microtron. The current in

these coils will be adjusted to put the second (29 MeV) orbit on the linac

axis after traversing D8 and D7. This magnet geometry will then return

all higher energy orbits to the linac axis without further adjustment

(except minor steering correcting). The arrangement of series coils was chosen because, (for example) if three independent power supplies were

used for D6, D9, and DIO, the current stability requirement would be at

least an order of magnitude more stringent.

We have performed ray-tracing calculations to verify that longitudinal phase space growth in the revised microtron design is acceptable. In the course of performing these calculations, we discovered that the treatment of radial forces in the accelerator section by the microtron raytracing program "PTRACE" is quite poor under some conditions. This inaccuracy has no effect on the longitudinal phase space, but affects the

transverse focussing significantly at low energies. We are in the process

of replacing the accelerator section transverse force algorithm in PTRACE

with the corresponding algorithm from PARMELA.

4. Extraction Beam Line

l __ At this time last year it was planned to transport the RTM beam

through the linac tunnel and into the adjacent measurement room ( MR 1 ) for

nuclear physics research immediately upon completion of this project. In the meantime, this plan has been deferred. Consequently, we have been

able to make a slight simplification to the extraction beam line design

which was presented in last year's report. For energy analysis, the ex- tracted beam will now be deflected 45° by bending magnet D14, as shown in

figure 8. A wirescanner located at the focus of D14 will be used to measure the beam energy spread, and a beam dump will be located approximately

1 m past the wirescanner.

C. RF System and Structures

1. Introduction

In FY 1985 most of the RF system has been completed and installed at

NBS. Major accomplishments are: installation and commissioning of the 65

kV dc power supply, klystron, and crowbar at NBS; installation, alignment

and commissioning of the 5 MeV injector linac at NBS; interfacing and

testing of the computer controls for the RF system; and completion of

construction of the 12 MeV linac.

2. RF Power System

The RF power system consists of a 65 kVDC power supply, a 450 kW CW

klystron, a crowbar unit, and an RF circulator to protect the klystron

127
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Division 535, CW Accelerator Research (Microtron) (cont'd.)

from reflected power. This system has been in operation at Los Alamos

since 1983. At NBS, a second power supply was installed in 1981 and a second klystron was delivered in 1982. A crowbar unit for the NBS system

was developed at Los Alamos. During FY 1985 the NBS system was brought

into operation: the power supply was commissioned; the klystron was installed and tested; and the crowbar and circulator were received from Los

Alamos, installed, and tested.

The variable transformer of the NBS power supply was returned to the

vendor in October 1984 after the "identical" unit at Los Alamos selfdestructed during a crowbar firing because of unrestrained coils. After

examining the transformer, the vendor decided it differed from the Los

Alamos unit and required no modification. It was returned to NBS in

December 1984 and reinstalled. Following approximately one month of

operation, the NBS transformer also failed. Currently, we are installing

the Los Alamos transformer at NBS while the vendor rebuilds the NBS unit.

Bringing the NBS power supply into operation required a large effort.

The vacuum circuit breaker on the 13 kVAC input line did not work initially and required alignment. The wrong control voltage was present in the

power supply because the wrong voltage transformer had been installed.

There was no regulation of the output voltage. There was no interlock to

prevent operation in the absence of the DC voltage which is required to

trip the vacuum breaker, a fault which could destroy the klystron. The

vendor has been very helpful in resolving these problems.

The power supply has been operated at full output voltage with no load. An output voltage ripple of 1.6% peak to peak is present at 50 kVDC

output voltage under load. This ripple is outside the specified 1% maxi- mum but will not present a problem for injector linac operation: it was demonstrated at Los Alamos that the RF amplitude control system can com- pensate for ripple of up to 2%. If reduction to 1% is desired, it will be

undertaken after beam tests of the injector linac.

At NBS the cables between the power supply and the crowbar unit are about 120 m long. To minimize stored energy in these long cables, the

high voltage is carried on the center conductor of two cables in parallel.

The crowbar has been tested and performs well, quenching sparks in less

than 20 usee. In some test firings of the crowbar unit, components were damaged so that the fast trigger of the quenching circuit failed to fire

in subsequent tests. In all such cases, a slower, backup trigger remained

effective and quenched the discharge. Reliability of the crowbar has been

improved through redesign.

After the klystron and associated cooling water system were installed

at NBS, the klystron was conditioned and tested by operating into a dummy

load. In order to stay on schedule in spite of the unanticipated work on

129
Division 535, CW Accelerator Research (Microtron) (cont'd.)

the crowbar, these tests were restricted to proving klystron performance

adequate for injector linac operation. The klystron was conditioned to 60

kVDC (90% maximum) and was tested to 250 kW RF output.

3. Injector Linacs and Controls

In November 1984, RF phase and amplitude stability measurements of

the injector linac were taken at Los Alamos. The measured variation in 1 hour or more is as follows:

Capture section phase

Capture section amplitude

Preaccelerator phase

Preaccel erator amplitude

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of the RTM.

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In November 1984 the injector linac along with the RF power distribution and control systems (waveguide, phase shifters, power splitters, RF

phase and amplitude controls, and accelerator cooling water temperature

control system) were shipped from Los Alamos to NBS. The injector linac was installed at NBS and put under vacuum in December 1984. The RF power

distribution and control systems were installed at NBS in the period

January - June 1985. In the same period, separate cooling water systems

for the circulator and waveguide were constructed and installed. In July

1985 the installed RF system was tested for correct operation, and the

injector linac was reconditioned to its operating RF power level.

In August the injector linac accelerated an electron beam for the

first time. The capture section was powered to 25 kW and accelerated the

beam to the expected energy, 1.3 MeV. Before the preaccelerator could be

phased properly for acceleration, failure of the klystron power supply

variable transformer terminated the beam tests.

4. 12 MeV Linac

The main microtron linac is composed of two four-meter-1 ong sidecoupled accelerator tanks. Each tank is made up of five separate brazed

copper sections that are bolted together with special RF and vacuum

joints. These two linac tanks have a total of 126 accelerating cells and are designed to support an accelerating gradient of 1.5 MeV/m and to provide an electron energy gain of 12 MeV per pass. Each tank has its own temperature/resonance control loop and independent RF phase and amplitude

130
Division 535, CW Accelerator Research (Microtron) (cont'd.)

control. Each tank requires a power feed of 108 kW to maintain the design

accelerating gradient plus the power transferred to the beam. Thus at

full beam power (100 kW, of which 95 kW is added in the microtron stage),

the two tanks together are driven with 310 kW of CW RF power.

The final braze in the fabrication of the main linac was completed in

early July. Both tanks were then assembled and tuned. The linac is now complete, including assembly and testing of the plumbing, temperature

control, and vacuum systems. The magnetic shields have been fitted, and

the residual magnetic field on axis was measured at less than 35 mgauss.

The linac will be shipped from Los Alamos to NBS where it will be installed and power-tested.

D. Beam Line Instrumentation

During FY 1985, beam line instrumentation for the 5 MeV injector was developed, constructed, and installed. This instrumentation consists of

wirescanners, viewscreens, beam stops, and RF phase, position and current

moni tors

.

Five wirescanners have been constructed and installed in the injector

system. These scanners will be able to measure beam size and position

with both CW and pulsed beams. Three wirescanners were used earlier to

measure the 100 keV injector emittance and achieved their design goal

position resolution of 0.05 mm. New amplifiers for the wirescanners were

also constructed, with remotely switchable gain and CW/pulse modes. Ten

wirescanners are now under construction for the next phase of the project.

Our wirescanner design has attracted a lot of outside interest. We

have built and delivered two wirescanners to the Accelerator Laboratory of

the University of Saskatchewan and to the MIT-Bates Linac. Two additional

wirescanners have been ordered by the Mass Spectroscopy Group at NBS for use with an isotope separator. We provide these devices on a costrecovery basis with the condition that work of this kind does not delay

the RTM schedule.

Five viewscreen mechanisms have been constructed and installed with

their associated TV cameras in the injector system. These viewscreens,

which are identical to the three already in use on the 100 keV beam line, are suitable for pulsed beam operation only. A computer-operated switching matrix is currently being installed to route the viewscreen current

and TV viewscreen images to the control console.

Two beam stops have been constructed and installed on the 5 MeV beam

lines to obtain accurate current measurements of the 5 MeV beam. One of

the beam stops is designed for up to a 30 MeV, 25 kW beam since it will

131
Division 535, CW Accelerator Research (Microtron) (cont'd.)

later be used to stop and measure the beam for one- and two-pass RTM operation. Both beam stops are heavily shielded to reduce radiation backgrounds in the RTM room to prevent damage to electronic components.

After the successful completion of tests with a prototype RF beam

monitor, as discussed in last year's annual report, two RF beam monitors

and their associated electronics were assembled and installed at the en- trance and exit of the injector linac. These monitors measure position,

current and phase for both CW and pulsed beams. The phase measurement is

especially important as it allows the correct phasing of the RF to the

accelerators to be determined. Two additional RF monitors are now under

construction for use on the main axis of the microtron. A computer-controlled switching matrix is also under construction to switch monitor

outputs to the control console display. Additional instrumentation has

been developed as part of the accelerator protection interlock chain.

These include vacuum monitoring, beam spill (radiation) monitors, and

temperature, water, and air pressure interlocks.

E. Control System

1. Introduction

All control system components and subsystems have been installed

during the past year that will be needed for essential control and monitoring functions for 5 MeV beam tests. With these and some additional

components, most of the basic control system that will be necessary for

full accelerator operation is now installed. The primary station, RTM

secondary station, and the three magnet tertiary stations were all delivered from Los Alamos in November and subsequently installed. All control system racks necessary for completion of the control system have now been installed in the electrical service cubicle. The present architecture of the control system, slightly modified from that described in last

year's report, is shown in figure 9.

2. Primary Station

Permanent installation of the primary station in the control room, as well as the RTM secondary station and magnet tertiary stations, was com- pleted in December. This consisted of modifying the AC wiring of the

racks to NBS specifications and making the final AC, rack-to-rack , and

primary-to-secondary station interconnections. Additionally, all beam

line devices required for 5 MeV operation were connected to the appropriate control outputs or monitoring inputs. During the installation of the

primary station a need for remote reset controls at the primary console,

for the individual secondary stations, was recognized. The necessary re- set controls were designed and installed as part of the primary-to-secondary link cabling. Other devices, such as dual 9-inch monochrome TV moni132
133

Figure

9

Control

System

Configuration.
Division 535, CW Accelerator Research (Microtron) (cont'd.)

tors for the viewscreen cameras and dual 350 MHz oscilloscopes for the RF

beam position monitors have also been installed in the primary console.

By the end of January, functional testing of the primary control

system was completed sati sf actori ly . This included establishing and testing all three primary-to-secondary-station data links and the serial links

between the four tertiary stations and their correspondi ng secondary stations. Control and monitoring of devices from the primary station console

through the appropriate secondary and tertiary stations was successfully

demonstrated

.

Included in the primary station, as delivered, is a second microcomputer system to provide higher level control and monitoring functions than

those provided by the main primary station processor. This system is

based on an 8085 8-bit single board computer identical to those used

throughout the RTM control system. It differs from the design proposed in

last year's report, a CP/M-86 system using an Intel 8086 16-bit microprocessor. During software development for the 16-bit system, several design

flaws were discovered in the commercial processor board being used that

precluded further development along these lines. Fortunately, due to our extensive prior experience with the 8085 processor board, the switch to

this board required little additional design effort. The performance of

the CP/M-80 system, while lower than that expected from the rejected 16-

bit design, has proven to be sati sf actory . In fact, the overall performance of the primary station has been increased by removing the CP/M system

from the primary control system bus to an independent bus, thereby considerably reducing the primary control system bus traffic. By using a shared, dual -ported, random-access memory for exchange of data between the

CP/M and primary control system processors, no reduction in data transfer

rate was observed between the two, now independent, processors.

After completion of the functional testing of the entire hierarchical

control system (primary, secondary, and tertiary stations) functional

testing of the CP/M system was performed. The following CP/M system functions were tested and found to operate satisfactorily:

(1) Saving and restoring control parameter block lists to/from CP/M

system floppy disk storage;

(2) Backing up and restoring the complete data base of any one of

the three secondary stations to/from CP/M system floppy disk

storage;

(3) Automatic control or monitoring of any accelerator parameter;

134
Division 535, CW Accelerator Research (Microtron) (cont'd.)

(4) The acquisition and plotting of one accelerator parameter as either a function of time or as a function of a second accelerator parameter on a 19-inch high-resolution color monitor.

With the completion of these tests, the basic hierarchical control system

is complete and functional for 5 MeV beam tests. Remaining control system

tasks to be accomplished in preparation for full machine operation include

completion of the link between the primary control system and the PDP11/44 computer; and design, construction, and installation of the wirescanner display system.

3. RF System Controls

The klystron control electronics and much of the remaining RF control

electronics were delivered to NBS with the capture and preaccelerator

structures in November. As a result of the decision to ship the RF

secondary station to NBS earlier for chopper/buncher tests, prior to the

completion of the RF system design at Los Alamos, considerable unanticipated effort at NBS was required to interface the RF secondary station with

the more recently delivered RF control electronics. Because development

of the RF control system continued at Los Alamos after shipping the RF

secondary station to NBS, numerous bugs were left in the installed but

untested RF controls in the RF secondary. Also, new control and monitoring functions were developed that had not been included in the RF secondary station as shipped to NBS. These new functions often conflicted with

existing input/output functions in the secondary station that were not

present in the temporary system used for RF control tests at Los Alamos

after shipment of the RF secondary to NBS. Thus, approximately three man months of additional effort was required after delivery for debugging and

retrofitting of the RF secondary to achieve satisfactory operation of the

RF control and monitoring system.

4. Interlocks and Vacuum System Controls

During the past year the design, construction, and installation of

the permanent replacements for the temporary interlock and vacuum control

systems were accomplished. This was a very large effort requiring approximately two man years of work. Careful and conservative design techniques

were employed to maximize the reliability of these two critical control

subsystems. For example, extra design effort was expended to develop a printed circuit design for the interlock chain plug-in relay cards and a pin and socket card-to-backpl ane interconnect selected for increased reliability, over the more conventional card edge connector system. Electromechanical relays are used for the interlock chain itself, and noiseimmune (HNIL) solid state logic circuits are used to provide latched sensing of interlock faults to the control system. A fault condition in an interlocked device opens the output of the interlock chain, simultaneously

135
Division 535, CW Accelerator Research (Microtron) (cont'd.)

switching off the electron gun high voltage bias and chopper/ buncher RF

drive. Switching off the chopper/buncher RF drive is the fast protect

mode, blocking transmission of the electron beam at the chopping aperture

in the 100 keV beam line.

The vacuum control and monitoring system was also designed to use electromechanical relays for maximum reliability. A typical vacuum system

control and status display panel, and its correspondi ng manual override

panel, is shown in figure 10. A similar set of panels have been constructed for the RTM and extraction line portions of the accelerator. A number

of fault condition interlocks are included between the vacuum control and

interlock systems. These prevent or interrupt operation of the accelerator when any monitored vacuum point is outside of preset limits or when a valve position is inappropri ate for the production of beam. The manual

override panel is also interlocked to prevent operation of the accelerator

when the vacuum control system is switched to the manual mode of operation. Additional interlocks are included between the RF and vacuum systems to switch off the RF power in the event preset vacuum limits are exceeded in any of the four accelerating structures.

5. Injector Secondary Station Modifications

In the past year, several additional steering and focussing magnets

were added to the 100 keV beam line. The interface on the injector

secondary station did not accommodate the additional power supplies re- quired. Therefore, a new modular magnet power supply interface was designed, constructed, and installed. The new interface will accommodate

additional power supplies if required in the future.

6. Magnet Mapping Systems

Early in FY 1985, the electrical interface between the PDP-11/44 and

the end magnet mapper system was completed. This interface included control of the 1500 A end magnet power supply from the PDP-11/44. After

completion of testing of the interface, the software for controlling the

mapper operation and the logging of data was written and debugged. This

system has been successfully used to map the fields in the first end magnet.

Recently, a new small -magnet mapping system was constructed to automate the field mapping of the numerous small magnets required for completion of the project. It consists of a Hall probe and a thermocouple probe

mounted on a two-dimensional stage, optical scales to measure probe coor- dinates, and a microprocessor-based control system to acquire and store

data. The mapper control system consists of one of the project's two

software development systems, modified by the addition of appropriate

136
Figure 10 Photograph of injector vacuum control panel.

137
Division 535, CW Accelerator Research (Microtron) (cont'd.)

hardware and software. Functional testing of the small magnet mapping

system has been completed sati sf actori ly

.

7. Maintenance

As the control system approaches completion, the work is shifting

away from design, construction, and installation of new control components

and software towards maintenance of the present system, many components of

which have been in operation for several years, and modifying and improving the operation of existing subsystems and functions. As the complexity

of the system continues to increase, the amount of effort necessary to

maintain the system is expected to have a proportionate increase.

138
LINAC OPERATIONS

Division 535, Radiation Source and Instrumentation Division

The NBS Electron Linac was designed in 1960 with maximum flexibility

in order to support a wide variety of program activities of interest to

NBS. Major users of the linac in FY 1985 included programs in neutron

cross section standards and radiography, high energy electron scattering,

photonuclear research, and activation analysis. The last is an activity

of the Center for Analytical Chemistry. In addition, a number of outside

col 1 aborators and guest workers participated in the above mentioned programs .

The Linac Operations staff has in spite of its relatively small size,

achieved a highly commendable operating efficiency as described below.

The staff operates and maintains the facility as well as designs, con- structs, and installs new equipment to improve operations and extend the

capability of the Linac and the beam handling system. The Mechanical

Instrumentation Group within the Division provides help by maintaining the

integrity of the vacuum and cooling systems of both the Linac and beam

handling system as well as designing, constructing, and installing mechanical components. Table I shows the distribution of the total Linac Operations staffing time in operation of the facility for FY 1985 (through July

1985). The facility is staffed from 7:30 am Monday morning and runs for

experiments until 6:30 am Saturday. Scheduled maintenance hours have

varied throughout the year.

Experiment time on the facility is requested by and allocated to users at scheduling meetings which were held normally every four weeks.

Time requested by experimenters did not come up to 100%. Table I shows an unscheduled time of 168 hours. This was a result of several of our users

not being able to schedule time due to equipment failure and then taking

part in long range planning activities. A new item added is time down due

to RTM operation at 320 hours. Table II shows the distribution of time by

experiment for the fiscal year.

The unscheduled maintenance of 213.5 hours, through August 1, is

broken down and summarized by system in Table III. The small amount of

unscheduled maintenance is due in part to having several extra periods

during RTM operations to do preventive maintenance.

The RTM is operational to an extent that testing is now necessary,

and since the building water cooling system will not permit both the Linac

and the RTM to operate simultaneously, their operations must be scheduled

jointly. The long range plan is to operate the Linac approximately 1/3 of

the time and the RTM 2/3 of the time. With our operational staffing and

assuming an 80% efficiency of operation this should give us about 1200

hours of Linac beam time and about 2400 hours of RTM time a year. The

139
Division 535, Linac Operations (cont'd.)

major Linac user is the Neutron Group, with small amounts of time available for analytical chemistry and others as required.

TABLE I

LINAC OPERATIONS

Month/Year through Aug 85 Scheduled Hours Actual Hours

Mai ntenance 312.0 312.0

Unscheduled Maintenance — 213.5

Beam Time 2502.0 1915.0

Set-Up 1 98.0 101 .

5

5

Experimental Down-Time2 — 370.0

RTM4 320.0 320.0

Unscheduled Time 168.0 168.0

TOTAL HOURS3 3400.0 3400.0

includes lock-up after scheduled maintenance.

2 Linac available for operation, but experiment either not ready or breaks

down during scheduled run.

3 Total staffing hours.

4 During RTM scheduled time preventive maintenance was performed.

5 Th i s includes 470 hours of training during set up.

140
LINAC

OPERATIONS

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141
Division 535, Linac Operations (con'd.)

TABLE III

LINAC OPERATIONS

FY 85

LINAC: Total unscheduled maintenance 213.5 hours

System:

Modul ators 90.0 hours 42 . 4%

Injector 51 .5 hours 24.1%

RF Drive 8.0 hours 3.7%

Vacuum 7.5 hours 3.5%

other system or item over 2%.

BHS: Total unscheduled maintenance 39.5 hours.

Balance of total unscheduled maintenance, 17 hours, due to air conditioning and power outage.

142
INSTRUMENTATION SERVICES

Division 535, Radiation Source and Instrumentation

Electronic Instrumentation Maintenance and Construction

Provision of electronics instrumentation maintenance and construction

services for the experimental programs of the Center for Radiation

Research is a continuing responsibility of the Radiation Instrumentation

Group in the Division. Instruments designed and constructed during 1985

number about 90 and maintenance has involved about 120 instruments.

Instrumentation Design and Construction

Design and construction of experiment and system control and interlock instrumentation is a continuing and important element of the

Radiation Instrumentation Group activities. Examples of this instrumentation this year include: RTM injector, vacuum control and safety interlock

system design and construction; RTM magnetic field mapper table probepositioning system design and installation; neutron spectrometer target

ladder programmable oscillator designed and installed; new instrumentation system for the States Regional Calibration Centers designed and con- structed and modification of the original systems to new specifications;

300 KV x-ray calibration system computer controller; high-voltage systems

safety interlock design and installation; various computer communication

links; x-ray calibration source automation; design and construction of a water-graphi te micro-calorimetrer measurement system; RTM wire scanner and

position-monitor amplifiers; miscellaneous control circuits for shutter, vacuum systems, position monitors etc.

Instrumentation Support for Physics and Chemistry Projects

Consulting and systems instrumentation has been provided to scientists in programs relating to neutron physics, electron physics, surface

electron physics, x-ray dosimetry, radiation chemistry, vacuum ultraviolet

physics (SURF), analytical chemistry, physical chemistry and photometry.

In addition, very considerable support has been provided for RTM projects,

one Group technician being assigned full-time to the project with extra

assistance on a requirements basis apart from the systems noted above.

The terminal of the 4 MeV electron Van de Graaff was redesigned and

rebuilt to accomplish beam pulsing. The beam can now be pulsed repetitively, reliably, with ultra stable and glitch-free pulses from about 5 ns to 5 ys widths, switch selectable. This effort was in support of the

radiation chemistry pulse-radiolysis program. Having completely rebuilt

the 3 MeV positive ion Van de Graaff last year, the Group has now redesigned and constructed new and much more reliable circuits to replace the

143
Division 535, Instrumentation Services (cont'd.)

original designs thus contributing to much greater operating reliability

and the achievement of record proton output currents. High voltage pulsed

louse drivers have been designed and installed in the STEM project and a very high voltage, bipolar pulse (±3 KV) driver has been designed and

installed as a Pockels cell driver. Both projects were for the Electron

Physics Group. In addition our Instrumentation Group has designed and

installed channel -pi ate multiplier amplifiers and high-voltage isolators

and analog signal -processi ng circuits for surface magnetic polarization

measurements [noted elsewhere]. Design and construction have started on a wire-chamber electron detector for electron scattering spectroscopy

.

Design of this detector was made possible only by the use of the computeraided design facilities in the Group 1 aboratories. Printed circuit boards

for the wires have been made and spacer frames manufactured. This chamber

will be completed in FY '86.

The Group continues to operate and maintain the HP 9845-based com- puter-aided design (CAD) system available to all NBS personnel. In addition, the Group has its own HP 9836-based system (newer and much faster).

Both systems have been fully utilized with a continuous wait in line for

the Group system. Without a CAD facility, effective Group operations

would be impossible; manual layout of current printed circuit-boards would

be much too time consuming. In addition, all Group technical drawings,

layouts, presentation overheads etc. are CAD made. Additional CAD facilities are urgently needed together with software development systems, hard- ware simulation systems and electronic design support. A new software

development system is on order but requirements for the other facilities

remain.

Much new equipment is urgently required if the Group is to maintain

its competence and effectiveness in providing service to the Center and

NBS. In addition to the CAD facilities above some of the Group needs

include a DC-22 GHz frequency synthesizer, another Tektronix 7000 series

oscilloscope, a fast logic timing analyzer, several MS/DOS- and Unix-based

microcomputers and a considerable amount of smaller general purpose, NIM

and CAMAC equipment.

Consultation by the Group expert staff continues to be important - not only to CRR but to other Centers in NBS. The cooperative AID program

with the Egyptian NIS and NOS continues and further developments await

delivery of equipment by the University of Wisconsin to these organizations in Cairo.

A new cooperative program with Harry Diamond Laboratories has been

started concerned with high-dose radiation effects on semiconductors. It

is anticipated that this will continue and should result in some innovative instrumentation.

144
Division 535, Instrumentation Services (cont'd.)

Mechanical Instrumentation Services

Mechanical instrumentation services were provided for the Center for

Radiation Research in connection with their particle accelerators and

their experimental programs. The services provided consisted of design

and construction of new equipment and facilities as well as maintenance

and modification of existing equipment to improve performance and reliability.

Instrumentation Design and Construction

Design and construction of mechanical devices is an ongoing and

important element of the mechanical instrumentation group activities.

Examples of these devices built this year are: 45° high precision dipole

magnets for RTM; RTM quadrupoles; high precision numerically controlled

magnet mapper for the RTM end magnets; 5 MeV and 35 MeV beam dumps for

RTM; electron beam target for neutron time of flight experiments. Modified RTM end magnets to achieve required field uniformity and maintenance.

Installation and Maintenance of Facilities

Another major element of our activities is installation and maintenance of major facilities. Examples this year are: installation of both

30 ton RTM end magnets including precision linear motion capability;

installation and alignment to ±.002" of the RTM injector linacs;

installation of 350 GPM water cooling system into RTM room; installation

of the RTM klystron; installation and alignment of the RTM Phase I transport system; installation of RTM RF distribution system including circulator; phase shifters and power splitters; rebuilt motor for the 3 MeV Van

de Graaff; rebuilt vacuum pumps for SURF and Linac; maintained mechanical

and vacuum equipment on linac to allow 93.5% beam efficiency.

The group staff continues to provide consultation service to other

groups in CRR and other NBS organizations. The staff is also consulted by

people outside NBS who build and operate accelerators worldwide.

A new CAD/CAM workstation has been installed and made operational.

In order to fully realize the potential of this technology several new workstations will be needed in the future.

145
RADIATION INSTRUMENTATION STANDARDS

Division 535, Radiation Source and Instrumentation

The Division provides national leadership in the standardization of

nuclear instrumentation. The standards work falls into three categories

as follows: (a) National Voluntary Standards - The Division plays an active role in the development and processing of Standards of the Institute of Electrical and Electronic Engineers (IEEE) and the American

National Standards Institute (ANSI) and participates in the associated

policy boards. L. Costrell serves as Chairman of ANSI Committee N42 on Radiation Instruments and as Secretary of the IEEE Nuclear Instruments and

Detectors Committee. In these capacities he has processed a considerable

number of ANSI and IEEE standards, serves on the ANSI Nuclear Standards

Board, and is a member of its Planning Committee.

(b) NIM Committee Standards - This involves development and maintenance of instrument standards, in cooperation with the National Laboratories, primarily for use in nuclear applications. NBS has the management

responsibi 1 ity for this work, with L. Costrell serving as Chairman of the

NIM Committee. The Nuclear Instrumentation Module (NIM) system has been

adopted nearly universally in the U.S. and is a continuous coordination

requirement involving contact with numerous laboratories and manufacturers. Similar management, direction and maintenance are provided in the

U.S. with regard to the international CAMAC (Computer Automated Measurement and Control) system that is utilized in the National Laboratories and

in a large number of other laboratories and installations throughout the

world. A third system for which the Division has similar responsi bi 1 i ty

is the FASTBUS high speed modular data acquisition system for high energy

physics and other applications. The FASTBUS development has been a major

effort and is well underway, with commercial equipment available and prototype systems in operation or in preparation in several laboratories in

the U.S., Europe, and Japan.

The preparation of reports for the above systems involves a number of

individuals and 1 aboratori es . Coordination and processing, as well as writing of some sections, is handled by the National Bureau of Standards.

The documents are usually issued as Reports of the Department of Energy

and then processed as Standards of the Institute of Electrical and Electronics Engineers (IEEE), the American National Standards Institute

(ANSI), and the International Electrotechnical Commission (IEC).

The Nuclear Instrument Module (NIM) system 1 ’ 2 has had a phenomenal

acceptance in laboratories and industry throughout the world. There is a continuous coordination requirement involving contact with numerous laboratories and manuf acturers and the resolution of questions that arise. In order to allow and encourage exploitation of technological development

146
Divi sion 535, Radiation Instrumentation Standards (cont'd.)

without impairing compatibility and i nterchangeabi 1 i ty, continued vigilance and direction is essential and is provided. The shift from discrete

components to integrated circuits and the increasing use of computers and

mi croprocessors necessitates continued accommodation to those devices.

Work is proceeding on updating the NIM standard in the light of developments and practice. Also, the division continues to provide information

regarding the CAMAC standards. 3

The FASTBUS standard has been issued as a Department of Energy

Report 4 and has also been approved as a standard of the Institute of

Electrical and Electronics Engineers (IEEE) and the American National

Standards Institute (ANSI) 5 with publication expected in late 1985 or early 1986. Processing as an international standard of the IEC is also

progressing with the draft for balloting purposes already submitted.

The NIM and CAMAC standard instrumentation projects have resulted in

a savings of at least 1.9 billion 1982 dollars according to a study conducted for the Department of Energy by a firm of economics consultants. 6 The study report states that the 1.9 billion dollars is considered to be a minimum figure conservati vely arrived at on the basis of available data.

1.7 billion dollars is attributed to the NIM system initiated by the

1 "Standard Nuclear Instrument Modules," AEC (now DOE) Report TID-20893

(Rev 4), July 1974 (currently under revision).

2 "Standard NIM Digital Bus ( NIM/GPIB) ," Department of Energy Report

D0E/ER-01 73, August 1983.

3 CAMAC Instrumentation and Interface Standards, IEEE Publication SH08482,

Library of Congress Catalog No. 8185060 (ANSI/IEEE Stds 583, 595, 596,

675, 683, 726, 758).

4 "FASTBUS Modular High Speed Data Acquisition and Control System," DOE

Report D0E/ER-0189, December 1983.

5 "FASTBUS Modular High Speed Data Acquisition and Control System,"

ANSI/IEEE Std 960-1984.

6 "Benefit Analysis of Selected Accomplishments of DOE

1

s Office of Health

and Environmental Research," Final Report RR-166, November 29, 1982,

Ecosometrics, Inc. (M. Lago, M.J. Ramsdell, S.F. Knapp, S.I. Siddique,

Bethesda, MD.

147
Division 535, Radiation Instrumentation Standards (cont'd.)

Center for Radiation Research 7 and the balance of 200 million dollars to

the CAMAC instrumentation system developed by the ESONE Committee of

European Laboratories with the active collaboration of the U.S. NIM

Committee and the CRR. The report adds: "The benefits were estimated

only if they could be documented from the literature or telephone contacts. There are a number of other direct and indirect benefits associated with the use of CAMAC and NIM interfaces which were not considered in

this analysis because no measureable data were available." The total

worldwide savings can be reasonably projected to be double the U.S savings .

(c) International Electrotechnical Commission - L. Costrell serves

as Technical Advisor to the U.S. National Committee of the IEC for IEC

Committee TC45 on Nuclear Instruments. He serves as Chief U.S. Delegate

to TC45, as Chairman of the Working Group on Detectors and as a member of

the working groups on Interchangeabi 1 ity and on Terminology. Numerous IEC

draft documents were prepared and reviewed resulting in a number that were published and others that are to be published. These include documents

that are technically identical to the NIM and CAMAC standards. 1 ’ 2 ’ 3 Similarly, the FASTBUS document being processed as an international standard is to be technically identical to ANSI/IEEE Std 960-1984. 5

7 "Standard Modules for Nuclear Instrumentation," NBS Report 8137,

December 5, 1963, L. Costrell.

148
INVITED TALKS

Division 535, Radiation Source and Instrumentation

Penner, S., "Progress Report on Accelerator and Fusion Research

Berkeley, CA, April 12, 1985.

the NBS/Los Alamos Racetrack Microtron",

Division, Lawrence Berkeley Laboratory,

149
PUBLICATIONS

Division 535, Radiation Source and Instrumentation

Ayres, R.L., Martin, E.R., Trout, R.E., Wilson, B.L., and Yoder, N.R.,

NBS/LANL Racetrack Microtron Control System, 1985 Particle Accelerator

Conference, IEEE Transactions on Nuclear Science, NS-32 , October 1985.

Dawson, W.K., Costrell, L., Ikeda, H., Ponting, P.J., and Walz, H.V.,

FASTBUS for the Particle Accelerator Laboratories, 1985 Particle Accelerator Conference, IEEE Transactions on Nuclear Science, NS-32, October

1985.

Debenham, P.H., Lindstrom, E.R., and Mohr, D.L., End Magnets for the NBSLos Alamos Racetrack Microtron, 1985 Particle Accelerator Conference, IEEE

Transactions on Nuclear Science, NS-32 , October 1985.

Lawson, J.D., and Penner, S., Note on the Lawson-Penner Limit, IEEE

Journal of Quantum Electronics, Vol . QE-21, No. 2, February 1985.

Penner, S., Ayres, R.L., Cutler, R.I., Debenham, P.H., Lindstrom, E.R.,

Mohr, D.L., Rose, J.E., Unterweger, M.P., Wilson, M.A.D., Biddle, R.,

Martin, E.R., Stovall, J.E., Tallerico, P.J., Wilkerson, L., and Young,

L.M., Progress Report on the NBS/Los Alamos RTM, 1985 Particle Accelerator

Conference, IEEE Transactions on Nuclear Science, NS-32 , October 1985.

Wilson, M.A., Cutler, R.I., Mohr, D.L., Penner, S., and Young, L.M., Performance of the 100 keV Chopper/Buncher System of the NBS-Los Alamos RTM

Injector, 1985 Particle Accelerator Conference, IEEE Transactions on Nuclear Science, NS-32 , October 1985.

Young, L.M., and Cutler, R.I., Performance of RF Beam Monitor on the NBSLos Alamos Racetrack Microtron, 1985 Particle Accelerator Conference, IEEE

Transactions on Nuclear Science, NS-32, October 1985.

150
TECHNICAL AND PROFESSIONAL COMMITTEE PARTICIPATION AND LEADERSHIP

Division 535, Radiation Source and Instrumentation

Robert L. Ayres

Member, ANSI Technical Committee N42.2 on Procedural Standards for

Calibration of Detectors for Radioactive Materials

Member, CRR Word Processing Task Force

Member, IEEE P1014/VMEbus Standard Committee

Member, NBS RIF Assignment Panel

Member, Science and Technical Pool, Science Panel, Committee on Interagency Radiation Research and Policy Coordination (CIRRPC)

Member, NBS Storeroom Committee for ADP

U.S. Representative, Life Sciences Working Group of the International

Committee for Radionuclide Metrology

Louis Costrell

Chairman, ANSI Technical Committee N42, Nuclear Instruments

Chairman, IEC/TC45 Working Group-9 on Radiation Detectors

Chairman, DoE National Instrumentation Methods (NIM) Committee

Chief U.S. Delegate, International Electrotechnical Commission (IEC),

Technical Committee on Nuclear Instruments (IEC/TC45)

Member, ANSI Technical Committee N41, Controls, Instrumentation, and

Electrical Systems for Nuclear Power Generating Stations

Member, IEC/TC45 Working Group-1 on Classification and Terminology

Member, IEC/TC45 Working Group-3 on Interchangeabi 1 i ty

Member, 1985 Particle Accelerator Conference Organizing Committee

Member, U.S. National Committee of International Electrotechnical

Commission (IEC)

151
Division 535, Technical and Professional Committee Participation and

Leadership (cont'd.)

Secretary, Institute of Electrical and Electronics Engineers Nuclear

Instruments and Detectors Committee of IEEE Nuclear and Plasma

Sciences Society (IEEE/NPSS)

Technical Advisor, U.S. National Committee of IEC

Philip H. Debenham

Member, DoE POISSON Working Group

Member, DoE Small Business Innovation Research Review Panel

Member, 1985 Particle Accelerator Conference Program Committee

Participant, DoD Emerging Technologies Workshop

Samuel Penner

Chairman, 1987 Particle Accelerator Conference

Member, DoE Aladdin Upgrade Review Committee

Member, Organizing Committee for 1986 Heavy Ion Fusion Workshop

Member, 1985 Particle Accelerator Conference Program and Organizing

Commi ttees

Member, Review Committee for the "Review of Scientific Instruments"

Julian K. Whittaker

Chairman, NBS Property Review Advisory Board Panel

Member, ASTM Committee D- 22 on Methods of Sampling and Analysis of

Atmospheres

Member, DoC Industry and Trade Administration, Electronic Instrumentation Technical Advisory Committee

152
Division 535, Technical and Professional Committee Participation and

Leadership (cont'd.)

Neil D. Wilkin

Member, Electronics Storeroom Committee, NBS

Mark A. Wilson

Member, Organizing Committee for Heavy Ion Fusion Workshop

153
MAJOR CONSULTING AND ADVISORY SERVICES

Division 535, Radiation Source and Instrumentation

1. R. Ayres serves as a member of the U.S. Pharmacopoeia Convention

Advisory Panel to the Subcommittee on Radiopharmaceuticals.

2. S. Penner and M. Wilson continue to provide Accelerator Technology

and Assessment and Oversight for DARPA.

3. S. Penner served on JASON panel to evaluate SDIO sponsored FEL programs.

4. J. Whittaker serves as a consultant on instrumentation and instrumentation maintenance and repair to AID for the Egyptian Government

Standards Laboratories.

5. J. Whittaker serves as a consultant on electronics instrumentation

and instrumentation repair and maintenance to the University of

Petroleum and Minerals, Dhahran, Saudi Arabia.

154
SPONSORED SEMINARS AND COLLOQUIA

Division 535, Radiation Source and Instrumentation

NBS Nuclear, Radiological, and Accelerator Physics Seminar, "The Design

Study for the Advanced Light Source," Richard Sah, Accelerator and Fission

Research Division, Lawrence Berkeley Laboratory, Gaithersburg, MD,

December 13, 1984.

155

TECHNICAL ACTIVITIES

Division 536, Ionizing Radiation

T ask No. 15201

Task No. 15221

Task No. 15225

Task No

.

15226

T ask No. 15227

Task No. 15602

Task No. 15645

Task No. 15231

T ask No. 15232

Radiation Standards Dissemination

Neutron Radiation Safety

Neutron Field Standards

Radioactivity Standards

Neutron Measurements and Research

Physical/Technological Property SRM Research

Computeri zation of Standard Reference Data Bases

Radiation Measurement Standards and Technology for Health

and Safety

Radiation Measurement Standards and Technology for

Industrial and National Programs

The Ionizing Radiation Division was formed on August 4, 1985 from

some of the groups of the former Nuclear Radiation Division and of the

Radiation Physics Division. The basic purpose of the organizational

change was to consolidate all programs in ionizing radiation measurements,

standards, and research in a single division. Nuclear physics research

activities in the old Nuclear Radiation Division were transferred to a new Nuclear Physics Group reporting to the CRR Director.

i n The functions of the new Ionizingthe following table:

Radiation Division are summarized

• Provides primary national standards, dosimetry methods, measurement

services, and basic data for applications of ionizing radiation (x

rays, gamma rays, electrons, neutrons, and radioactivity, etc.) in such areas as:

- Radiation protection of workers and the general public

- Radiation therapy and diagnosis

- Nuclear medicine

- Radiography

Industrial radiation processing

- Nuclear energy

- National defense

- Environmental protection

Conducts

physical

provide

theoretical and experimental research

and chemical interactions of ionizing

the competence for:

on the

radi at

fundamental

on with matter to

157
Division 536, Technical Activities (cont'd.)

- Developing improved understanding of the physical stage of the

interaction of ionizing radiation with matter.

- Developing an understanding of basic mechanisms involved in

radiation-induced chemical transformati ons and the parameters that

influence the yields of short-lived intermediates, final chemical

products, and biological effects

- Developing improved methods for radiation measurement, dosimetry,

and radiography

- Developing improved primary ionizing radiation standards

- Producing highly accurate standard reference data for ionizing

radiation or radioactive materials

• Provides essential standards and measurement support services to the

National Measurement Support System for Ionizing Radiation that

provides calibrations and measurement quality assurance services to:

- Medicine

Industry

- States

- Other Federal Agencies

• Develops and operates wel 1 -characteri zed sources of electrons, photons,

and neutrons to provide:

- Primary radiation standards and fields

- Well -characteri zed beams of radiation for research on radiation

interactions and for measurement methods development.

To carry out the functions of the Ionizing Radiation Division, the

initial group structure shown below has been adopted. As we understand

the mission and research program of the Ionizing Radiation Division

better, it is quite possible that the group structure will be modified to

reflect this understanding.

Ionizing Radiation Division Office (R. S. Caswell)

Office of Radiation Measurement (E. H. Eisenhower)

Radiation Theory (M. J. Berger)

Radiation Chemistry & Chemical Dosimetry (M. G. Simic)

Neutron Measurements & Research (0. A. Wasson)

Neutron Dosimetry (J. A. Grundl)

D. Hoppes)

W. Motz)

Dosimetry (R. Loevinger).

Radioactivity (D.

X-ray Physics (J.

Electron & Photon

158
Division 536, Technical Activities (cont'd.)

Office of Radiation Measurement

The function of the Office of Radiation Measurement is to promote the

dissemination to federal, state, and local radiation control programs, and

to the medical, industrial, and defense communities, of the measurement

standards and technology required for reliable measurement of ionizing

radiation. The Office assists the technical organizational components of

the Ionizing Radiation Division in monitoring the radiation measurement

needs of these national user groups, and in activities undertaken to meet

national needs. The latter include methods for improving the consistency

of field measurements with the national physical measurement standards.

The Office maintains liaison with organizations that conduct measurementintensive programs in the areas of radiation safety, energy, health, and

environmental contamination. Examples are the Nuclear Regulatory

Coirnii ssion, Department of Energy, Food and Drug Administration,

Environmental Protection Agency, Health Physics Society, and the

Conference of Radiation Control Program Directors. The Office participates in collaborative programs with most of these organizations to satisfy specific measurement quality assurance requi rements. Another function

of the Office is to provide the chairman for American National Standards

Committee N43, concerned with equipment for non-medical applications of

ionizing radiation.

Radon (R. Co 1 1 $ & J. M. R. Hutchinson)

The growing concern about exposure of the public to radon and radon

progeny throughout the United States has resulted in increased interest in

the quality of radon measurements. In response to this concern, the

Office has directed its activities toward developing new transfer standards and to maintaining liaison interactions with other radon measurement

1 aboratories . Significant progress was made in the past year.

For the development of new transfer standards, the Office continues

to collaborate and conduct laboratory studies with staff members of the

Radioactivity Group. These collaborative projects included the successful

completion of a radon-in-water standard, ongoing work to develop a flux

density standard, and extensive modifications to the radon measurement and

test facility.

A final version of the radon-in-water standard was transmitted to the

Environmental Protection Agency. This standard consists of a polyethylene-encapsulated radium solution source in a small-volume accumulation chamber, and an ancillary mixing and dispensing system. It generates aqueous solutions of radium-free radon of which multiple aliquots may

be dispensed and used as standardized solutions for calibrating radon-inwater assay procedures. In the past year, extensive performance tests were conducted on the standard, detailed operating instructions were

159
Division 536, Technical Activities (cont'd.)

developed, and the final calibration and certification of the standard was completed. A paper on the development and performance of the standard is

in preparation.

The Office continued to provide oversight for the overall project to

develop a flux density standard. This project is funded in part by an interagency agreement with the Environmental Protection Agency. A 40-cm

diameter prototype was fabricated, and it was loaded with a radium solution after a suitable circulation system and a safe and efficacious loading procedure were developed. Preliminary measurements on the prototype

were initiated in February, but had to be terminated because the polyethylene to stainless steel seal proved to be inadequate. The prototype had

to be dismantled, decontaminated, and modified to incorporate additional

0-ring seals. To save time (and hopefully avoid the need for ever having

to decontaminate or reload the prototype more than once again) an entirely

different and auxiliary experimental effort was undertaken. The goal was

to better understand and characterize the diffusion of radon through polyethylene in a configuration much simpler than the prototype. For this

work, a 2-liter "diffusion cell" was fabricated and used to measure the

diffusion coefficient, and to estimate the "relaxation time" for the source to reach a steady-state condition (i.e., a constant radon concentration profile in the polyethylene layer, and hence a constant flux density) as well as the relaxation time dependence on polyethylene thickness.

These auxiliary measurements with the diffusion cell were recently completed. The results for the diffusion coefficient and other parameters

are in good agreement with the initial design estimates. Following the

modification and reassembly of the prototype, we are at present conducting

further tests with the prototype loaded with just a gaseous radon source.

This configuration is very similar to the small diffusion cell studies. A

constant radon concentration is flowed through the prototype, and the

exhaled radon from the prototype surface is accumulated and continuously

monitored to evaluate the constrained flux density. On completion of

these tests, it is envisaged that the prototype will be reloaded with a radium solution before the end of the year. In collaboration with a staff

member from the Center for Materials Science, who derived a mathematical

model for the prototype, the design calculations performed last year were considerably extended to include time-dependent cases for the constrained

exhalation rate. This ongoing work on the development of a flux density

standard was reported at the annual Health Physics Society meeting in

Chicago

.

The radon measurement and test facility used for the above studies

was completely rebuilt in the past year. The old system was dismantled,

and a new all glass and stainless steel sampling and monitoring manifold

(separate from the 600-L test chamber) was constructed and extensively

tested. It has been fully operational since early Spring. The design of

this new system provides much greater range and flexibility in different

types of gas sampling and radon monitoring that can be performed.

160
Division 536, Technical Activities (cont'd.)

In addition to these laboratory studies, the Office continues to

coordinate the interactions and measurement intercomparison activities

between NBS and other radon measurement 1 aboratories, such as the DoE

Environmental Measurements Laboratory, the DoE Technical Measurements

Center (operated by Bendix in Grand Junction, Colorado), two EPA laboratories at Montgomery and Las Vegas, the U.S. Bureau of Mines Denver

Research Center, and national laboratories including Lawrence Berkeley

Laboratory, Argonne National Laboratory, Oak Ridge National Laboratory,

and Mound Laboratory. The Office also continued to advise and collaborate

with personnel in the State of Wisconsin Department of Health on calibration procedures for radon measurements and on the evaluation of a commerci al ly-avai 1 able radon source. In the past year, plans were made

for a collaborative radon flux density measurement i ntercompari son with

the DoE Environmental Measurement Laboratory, Colorado State University,

and the EPA Eastern Environmental Radiation Facility; discussions were initiated with the National Academy of Sciences and with other groups on the design of a national indoor radon survey; and additional contacts were

made with the Harvard School of Public Health and several international

1 aboratories.

Measurement Theory (R. Coll£)

The Office's expertise in the treatment and reporting of measurement

uncertainties continues to be very useful to groups both within and external to NBS. In the past year, many individuals and groups have been

assisted by the Office. In particular, an Office staff member served on a "panel of experts" for a workshop on error analysis held at the annual

symposium of the National Conference of Standards Laboratories. The

Office also made substantial contributions to the new sections on measurement assurance, traceabi 1 i ty, and the statement of uncertainty for the

second edition of the National Council on Radiation Protection and

Measurements report on radioactivity measurements procedures (NCRP Report

No. 58).

Regional State Laboratories (H. T. Heaton & E. H. Eisenhower)

At present the Office is cooperating with five states in establishing

regional calibration laboratories for ionizing radiation. The main radiation sources in these laboratories are a 150-kilovolt x-ray machine, with

filtration corresponding to five NBS beams, and 137 Cs irradiators with source strengths of 3 curies and 30 mi Hi curies. Beams from these sources

are used to calibrate survey instruments at radiation protection levels

and x-ray instruments used for diagnostics.

The laboratory in Springfield, Illinois continues to be the only one accredited by the Conference of Radiation Control Program Directors so far. Based on successful participation in a second performance evaluation, their accreditation for both x-ray and gamma-ray calibrations was

161
Division 536, Technical Activities (cont'd.)

renewed in July, 1985. To date they have calibrated instruments for nine

other state radiation control programs. This laboratory is considering

extension of its services to include calibration of instruments used for

monitoring environmental levels of radiation and calibration of pulsecounting instruments.

The laboratory in Seattle, Washington has successfully participated

in a performance evaluation for gamma-ray calibrations with the 3-Ci 137 Cs source. Revision of the procedures manual is underway and, when that is

sati sf actori ly completed, it is anticipated that the CRCPD will grant

accreditation for gamma-ray calibrations with the 3-Ci source. Until

accreditation is received for gamma rays, minimal effort will go into

developing the x-ray calibration capability. This laboratory is

presently performing unaccredited calibrations of survey instruments for

the Oregon and Washington radiation control programs.

Due to limited manpower availability, the laboratory in Columbia,

South Carolina is not developing as rapidly as expected. The 150-kV x-ray

machine is operating, and procedures for its use in calibrations are under

development. The 3-Ci 137 Cs source has been delivered but the necessary

shielding calculations and verifying radiation survey measurements have

not yet been completed.

Building modifications for the laboratory in Sacramento, California

have been completed and the x-ray machine was installed in August, 1985.

A training course in x-ray calibrations was provided by the Office for

personnel from the Radiological Health Section, Office of Emergency

Services, and Division of Weights and Measures. The laboratory recently

received authorization from FEMA to replace the 50-Ci manual ly-operated

source with a new 100-Ci pneumatical ly-operated 137 Cs source together with

a new calibration track system.

In Fayetteville, Arkansas, modifications to existing space are nearing completion. This laboratory will be developed with funds provided by

Congress in FY 1985. The existing capability to provide calibrations

using neutron sources will be expanded to include x-ray, beta-particle,

and gamma-ray capability. As a result of this expanded range of calibration services, it is necessary for the Radiation Measurements Committee of

the Conference of Radiation Control Program Directors to broaden their

accreditation criteria to include all of these sources and services.

Collaboration with personnel from the California Division of Weights

and Measures has resulted in the development of new procedures for calibrating the electrometer and picoampere current source used in each state

laboratory. A computer code is being developed that will allow the state

laboratories to calibrate these instruments on site, using a reference

voltage, standard resistor, and standard capacitor.

162
Division 536, Technical Activities (cont'd.)

Measurements of x-ray beam half-val ue-1 ayers at the Illinois and

South Carolina laboratories indicate that the preset machine kilovoltage

may not be the actual kilovoltage. Two methods of determining the actual

kV are being investigated. The first involves measurement of the halfvalue-layers using the NBS 150-kV machine under a set of specified conditions. This includes developing computer codes to unfold the energy

response of the ion chamber from the measured transmission values and a study of the systematics of various experimental conditions. The second

approach is to measure all of the components in the high voltage circuit

used to monitor the actual kilovoltage. This is being carried out in

collaboration with personnel from the California Division of Weights and

Measures

.

Committee Activities (H. T. Heaton, R. Col IS, & E. H. Eisenhower)

The Office serves on two major interagency committees concerned with

environmental radon exposure. The first is the Radon Workgroup of the

Interagency Committee on Indoor Air Quality (ICIAR). This group recently

completed a report on the status of current federal activities and priorities for radon research in the U.S. It also advised and assisted the

ICIAQ parent committee in developing a Comprehensive Indoor Air Quality

Research Strategy (published June, 1985). Future activities of the workgroup include a progress report on the development of a national indoor

radon assessment plan and the appropriate Federal role in conducting this

large-scale project. The second committee is the Science Subpanel on Radon Protection and Health Effects of the Committee on Interagency

Radiation Research and Policy Coordination (C1RRPC). The Radon Subpanel

was one of the first five working groups formed by the CIRRPC Science

Panel. A first report by this subpanel is in preparation. For this

report, the Office contributed a draft chapter on the status and quality

of radon measurements made in the U.S. and on other measurement considerations.

The Office has also participated in the activities of the CRCPD

Committee on Adequate Criteria for Environmental Monitoring and

Surveillance Programs. This committee, established last year, completed a draft criteria document. The document was distributed to the state radiation control program directors for review and comment, and is presently

undergoing a final revision.

For the past three years, a member of the Office staff has served as the Department of Commerce representati ve to the Interagency Working Group

on Occupational Exposure Guidance. This group, consisting of representatives of 10 government agencies or departments, assisted the Environmental

Protection Agency to prepare guidance that will replace the Federal

Radiation Council guidance issued in 1960. The new guidance has been

approved by all the participating agencies and will be submitted to the

Office of the President for publication in the Federal Register in the near future.

163
Division 536, Technical Activities (cont'd.)

After more than 38 years, MBS has relinquished the secretariat of

American National Standards Committee N43, Equipment for Non-Medical

Radiation Applications. The Committee considered offers of a new secretariat from four candidate organizations, and selected the Health Physics

Society. The Office will continue to provide the committee chairman until

the summer of 1987, at which time a new chairman will be elected by the

committee. In a closely related activity the Office prepared, during the

past year, a comprehensive glossary of radiography terms under sponsorship

by the Department of Defense.

Personnel Dosimetry (E. H. Eisenhower)

The national quality assurance program for personnel dosimetry operated routinely during the past year under the procedures of the National

Voluntary Laboratory Accreditation Program (NVLAP). Forty-seven dosimetry

processors have applied for accreditation and 26 of them have been accredited so far. The Nuclear Regulatory Commission is preparing a final rule

that would require its licensees to use only accredited processors, and a number of states have taken similar action. Technical support and guidance for this program have been supplied by the Office and the Dosimetry

Group. The Office provides the chairmanship of an interagency committee

that provides guidance and coordination for this national program.

I . Radiation Theory Group

Bremsstrahl ung Cross Section (S. M. Seltzer & M. J. Berger)

Work has been completed on the evaluation and tabulation of this cross section which is a key input for radiation transport and radiological physics calculations. This work includes not only the bremsstrahl ung

spectrum resulting from the Coulomb interactions of incident electrons

with screened atomic nuclei, but also the spectrum resulting from the

interaction of electrons with atomic electrons. The bremsstrahl ung cross sections were evaluated through the synthesis of results obtained with a variety of analytical and numerical methods. The methods used have been

described in a detailed expository paper, to appear shortly in Nuclear

Instruments and Methods, which also contains cross section tables for

selected elements. This paper also demonstrates, through extensive com- parisons that the tabulated cross sections are in good agreement with

experimental data. A complete set of bremsstrahl ung cross section tabulations has been submitted for publication to Atomic Data and Nuclear Data

Tables. This compilation includes the cross sections for electron-atom

and electron-electron bremsstrahl ung, for all elements with atomic numbers

Z = 1 to 100 for electron energies between 1 keV and 1000 GeV.

164
Division 536, Technical Activities (cont'd.)

Predictive Algorithm for Photon Cross Sections (M. J. Berger,

S. M. Seltzer, & J. H. Hubbell)

In radiological physics and radiation protection work, photon cross sections for scattering and absorption, as well as total attenuation coefficients may be required for an enormous variety of materials, too many to

allow convenient tabulation in print media. To overcome this difficulty,

a set of computer programs has been developed which can be used to obtain

photon cross sections for any material of interest, through the additive

combination of cross sections for atomic constituents. The codes take

into account the presence of the separate absorption edges for each of the

constituents, and also allow either for easy and accurate interpolation to

any desired set of photon energies or for output according to a standard

photon energy list. To facilitate the rapid and efficient execution of

the combination and interpolation algorithms, a cross-section data base

was developed for photon energies from 1 keV to 100 GeV and for elements

with atomic numbers Z = 1 to 100. Even though the computer programs (in

FORTRAN 77) are portable, the implementation of the programs is nevertheless slightly machine dependent. Several code packages have therefore

been developed, including batch-submission versions for Univac 100 and IBM

3081 computers, and interactive versions for IBM 3981 and Control Data

Cyber 855 computers. The interactive versions allow the user to enter the

composition of the material of interest in terms of chemical formulas at a terminal, and provide neatly organized cross section tables on the screen

or attached printer.

X-Ray Attenuation Coefficients for Crystal lography (J. H. Hubbell)

New and independent measurements of x-ray attenuation coefficients,

in wel 1 -char acteri zed single-crystal silicon samples, have been made in 12

cooperating laboratories in Australia, Denmark, India, Japan, Malaysia,

U.K., U.S.A., and Yugoslavia, constituting the first results of the

International Union of Crystal lography (IUCr) Commission on Crystal lographic Apparatus X-Ray Attenuation Project. This project, as originally proposed by NBS and inaugurated at the 1978 Warsaw Congress

(IUCr-11), is aimed at resolving serious discrepancies in the data in the

literature. In a manuscript for Acta Crystal lographica, coauthored with

the Project Chairman (D. C. Creagh, Australia), these measurements are compared with available theoretical values and with previous measurements

in the photon energy range 8 to 1173 keV. This evaluation suggests that

present compilation values for silicon should be lowered by amounts of the

order 5 percent in the region 20 to 50 keV and also that measurements in

silicon would be useful in the important region 0.277 to 6.4 keV, where no measurements have been made to date.

165
Division 536, Technical Activities (cont'd.)

The samples for this project have been fabricated and distributed to

23 laboratories by the Chairman (Creagh, Australia), and the NBS serves as Project Secretariat. Measurements are being made also on copper, germanium, magnesium, and pyrolytic graphite, which will be similarly evaluated

and reported in the crystal 1 ographic literature. Results of this project

will be taken into account in Sections 4.2.3 (X-Ray Absorption Coefficients Commentary) and 4.2.4 (X-Ray Absorption Coefficients) invited for

the International Tables for X-Ray Crystallography ( Vo 1 . C, new series) in

coauthorship with Creagh.

Critical Analysis of Soft X-Ray Cross Section Data (M. J. Berger &

E. B. Saloman)

A pilot project is in progress in the NBS Photon and Charged Particle

Data Center to collect and evaluate photon cross section data in the soft

x-ray region 100 eV to 10 keV. These data will provide input for compiling tables of recommended cross section values for a variety of technological and basic research applications. This project complements earlier

NBS evaluations and compilations which focused primarily on energies above

10 keV. In the present region of interest (soft x ray) the total cross section (attenuation coefficient) consists almost entirely of photoabsorption, with coherent and incoherent scattering contributions significant

only for the low Z elements. The NBS collection of experimental total

attenuation coefficients abstracted from the literature is now computerized to facilitate use and for future updating. These experimental data

have been compared for several key elements with theoretical photoabsorption (Livermore) in the range 1 to 100 keV. Stimulated by this NBS soft

x-ray data project, Scofield has made new photoeffect calculations extending down to 100 eV which will be similarly compared with available mea- surements. In addition, at the request of the NBS Photon and Charged

Particle Data Center, Doolen (Los Alamos) is doing new calculations

extending from 10 keV down to the eV region using the time-dependent

local -density approximation programs developed by Liberman and Zangwi 1

1

,

which will also be compared with the NBS measured-data collection as a NBS/LANL collaboration.

Penetration of Radiation Through Multi-Layer Media S. M. Seltzer &

M. J. Berger)

The Monte Carlo program ZTRAN has been debugged, and has been

described in a National Bureau of Standards report, NBSIR 84-2131. This

is a 1-D program which can be used to calculate the penetration, diffusion

and slowing down of electrons and/or photons in a medium consisting of

several slabs of different materials adjacent to each other. Comparisons

have been made in regard to energy deposition in various multilayer com- binations, and indicate good agreement between predicted and experimental

depth-dose distributions. Other typical problems, involving electrons

166
Division 536, Technical Activities (cont'd.)

with energies from 500 keV to 60 MeV, and various multilayer configurations (e.g. Al/Au), have been treated to indicate the utility of the program. These results have been presented in an invited paper at a Conference on the Application of Accelerators in Research and Industry

(November 12-14 1984), and will be described more fully in a paper now in

preparati on

.

Proton Energy Loss Straggling (M. J. Berger)

In the modeling of radiation effects on the cellular or subcellular

level, one often needs information about proton energy-loss straggling in

very short pathlengths (micrometers or fractions of mi crometers) . The

classical straggling theories of Landau and Vavilov have the limitation

that they apply only to sufficiently long pathlengths, and may be inaccurate for the distances often of interest in radiobiological modeling. An

alternative Monte Carlo method was therefore developed which is not subject to this limitation and can be applied to arbitrarily short distances.

This method has been implemented for a water medium, using reliable ionization cross sections that have recently become available. Energy loss

distributions in water have been calculated for protons with energies

between 0.5 and 20 MeV traversing pathlengths from 1 to 1000 mean-free

paths. The results indicate that the theories of Landau and Vavilov

(supplemented by the B1 unck-Lei segang correction) provide accurate results

only for pathlengths greater than about 100 mean-free paths.

Charged-Particle Spectra and Kerma Factors (J. J. Coyne, H. M.

Gerstenberg, and R. S. Caswell)

Methods have been developed for the systematic tabulation of the

energy spectra of charged particles released in neutron interactions with

tissue or tissue-equivalent solids and gases. The spectra treated include

both the initial spectra resulting from the nuclear interactions and the

energy-degradati on spectra resulting from the inelastic Coulomb scattering

of the released charged particles as they slow down to rest. The computational apparatus has been prepared for an extensive compilation which will

be useful for biophysicists engaged in the modeling of radiation effects.

Kerma factors (which are in effect energy-wei ghted integrals over the

initial spectra) have been calculated for H,C,N and 0 in neutron energy

bins 200 keV wide, covering the region from 0 to 20 MeV, and also for 76

logarithmic bins extending from thermal energies to 2 MeV. The information generated includes the contribution to the kerma factors from different particles and from different reactions. The publication of the kerma

factors has been delayed because of the uncertainty of the results for

alpha particles for neutron energies above 10 MeV. The variation of kerma

due to alpha particles in the reaction 12 C(n,n')3a has recently been

investigated and the results of this study will be used to improve the

kerma tables before publication.

167
Division 536, Technical Activities (cont'd.)

Microdosimetry for Neutrons (J. J. Coyne, H. M. Gerstenberg, & R. S.

Caswel 1

)

The analytical transport theory developed at NBS uses the continuousslowing-down approximation to calculate energy deposition in small sites

by secondary charged particles released in neutron interactions with tissue. Efforts are now underway to refine the method by including the

effects of energy-loss straggling of protons, and the effects of energy

transport by secondary electrons released in proton-impact ionization

events. Two approaches are being used: (a) the incorporation of straggling information into the analytical method; and (b) independent Monte

Carlo calculations. Pilot calculations made for 20-MeV and 14-MeV

neutrons and spherical 1-micrometer sites indicate that the straggling

effects are small but significant, and that the inclusion of these effects

will improve the agreement between calculated and measured microdosimetric

event-size distributions.

Neutron Transport and Dosimetry (C. M. Eisenhauer)

Calculations and measurements designed to characterize the neutron

and gamma-ray fields in the exposure rooms of the Armed Forces

Radiobiology Research Institute (AFRRI) have continued. Measurements of

neutron spectra made by Science Applications International Corporation

(SAIC) using activation foils were benchmarked by irradiating them in the

NBS 2 ^ 5 U fission neutron spectrum. Predictions of neutron fluence by

individual detectors showed departures of as much as 10 percent from the

NBS fluence. These biases must be taken into account when interpreting

other measurements by SAIC in AFRRI neutron fields. In addition, NBS made

measurements in the AFRRI exposure room 1 configured with a 6-inch Pb

shield. Analysis of these data showed that measurements with six

activation/fission foils together with the NBS spectrum adjustment code

SPAD could be used to obtain a kerma rate that agreed to within 1 percent

with the value obtained with tissue-equivalent ionization chamber.

Calculations were made with the ANISN computer code to aid in the

design of the shielding for a 252 Cf neutron check source for AFRRI.

In order to improve the NBS capability for calculating neutron and

gamma-ray transport, a Monte Carlo computer code MCNP has been obtained

from Los Alamos National Laboratory. Videotapes of a workshop on the use

of the code were also obtained. The code has been compiled on the CYBER

855 computer. Test runs will commence shortly.

International Radiation Physics (J. H. Hubbell)

For the Third International Symposium on Radiation Physics (ISRP-3),

Ferrara, Italy, Sept. 30 - Oct. 4, 1985, John Hubbell served as Secretary

for the International Programme Committee and Bill Ott and Martin Berger

168
Division 536, Technical Activities (cont'd.)

were members of the ISRP-3 International Advisory Board. This Symposium

is a sequel to ISRP-1 (Calcutta 1974) and ISRP-2 (Penang 1982), in both of

which NBS played major supporting roles (Ed Brady arranged publication of

ISRP-1 Proceedings as NBS- SP-46 1 ; Hubbell gave keynote address and

performed other organizing tasks). ISRP-3 is sponsored by the European

Physical Society and the Societa Italiana di Fisica, with support from

eleven other Italian scientific institutions, and has a scope including

the fol lowing topics:

(1) Cross sections for interactions between radiation and matter, and

other physical parameters characteri zi ng the primary events induced by

radiation in matter; (2) radiation transport; (3) properties, planning and

preparation of radiation sources; (4) properties and realization of radiation detectors; (5) radiation physics in fundamental research; (6) radiation physics in biomedicine and environmental science; (7) radiation

physics in technology and energy research; and (8) radiation physics

teaching at the university level.

II . Radiation Chemistry and Chemical Dosimetry Group

The program of the group deals with investigations of radiation

effects in chemical and biological systems from the early physical interaction of radiation and matter to final biological endpoints and the

dosimetry of radiation effects.

Radiation Chemistry (M. G. Simic, E. P. Hunter, L. Karam, W. L.

McLaughlin, M. Dizdaroglu, D. Bergtold, & M. AlShiekhly)

The associated chemical and biological processes are studied from a kinetic and mechanistic point of view at a molecular level. That approach

requires investigation of transient free-radical species by fast kinetic

techniques (pulse radiolysis), product measurement by a variety of ana- lytical techniques (GC/MS, HPLC, spectroscopy, etc.), and characterization

of bio-effects by suitable bio-chemical techniques (centrifugation, electrophoresis, etc.). The investigations are conducted in both simple and

complex model systems, as well as in cells. Cells are used because no model systems can mimic the microenvi ronment of DNA in living systems.

The major emphasis of the research is on damage and repair of DNA.

Since DNA is associated with proteins (histones) and is attached to membranes, some aspects of radiation chemistry of amino and fatty acids are also being investigated. The interest has, however been focused predominantly on the mechanisms of DNA base damage and crosslinking of DNA within

and with proteins. Crosslinking appears to be a major effect in cells.

Mechanisms and consequences of crosslinking however, are not yet understood because of the measurement problems. Irradiation parameters (dose,

dose rate, temperature, state, 0

2

, etc.) are of critical importance since

the effects of radiation can be qualitatively and quantitatively altered

169
Division 536, Technical Activities (cont'd.)

by them. The effects of quality of radiation (LET) are not investigated

at present. However, the study of the effects of low energy protons and

a-particles, as well as high energy high Z nuclei (BEVALAC) are in the

planning stage.

Impact . This research is expected to have an impact in radiation

biology, radiation therapy of cancer, cancer etiology, risk assessment,

radiation protection, and irradiation processing in general.

Specifically, it is relevant to: safety assessment of irradiated meats,

assessment of damage by low-LET radiations (y and x rays, electrons) vs. a-particles (e.g. radon), and development of standards for individual

biological sensitivity to radiation.

Chemical Dosimetry (W. L. McLaughlin, M. G. Simic, B. Radak, M. Farahani,

& W. Warasawas)

The investigated radiation effects, with kinetic and mechanistic

understanding, are subsequently utilized in the development of new methods

and concepts for radiation dosimetry. Currently, the activities are devoted equally to the development of novel and improved systems.

For convenience, the chemical dosimetry program is subdivided into

the following areas:

On-Line Dosimeters (OLD) . This is a classical type of dosimeter

which is carried for personnel protection or is attached to samples to be

irradiated. Optical wave-guide (OWG) dosimeters conceptually developed in

this lab in the previous years, have been shown to be suitable as personal

dosimeters, with lower sensitivity of about 1 rad. Further development is

in progress to increase their sensitivity to allow accurate dose measurements of about 10 mrad.

Research on dosimeters for (a) multi Mrad dose range, and (b)

neutrons (mixed low-and high-LET) is in preliminary stages.

Real-Time Dosimeters (RTD). Convenient chemical dosimeters which

could be read during irradiation are not available commercially. OWG

dosimeters have been adopted for low dose-rate real-time measurements, by

using common green and yellow LEDs and silicon photodiode and DMSO solutions of HHEVC. Further development is needed for RTDs with possible

application in radiation therapy and emergency dosimetry.

There is also need for the development of standard RTDs for ultrahigh dose-rates, with applications in nuclear weaponry and pulse radiolysis measurements (ns-us, up to 10 15 rad/s).

170
Division 536, Technical Activities (cont'd.)

Post Irradiation Dosimetry (PID). There are numerous instances when

the knowledge of the delivered radiation dose is required either immediately or long after the exposure. For example, proof that suspected foods

have or have not been irradiated is required by food processors and wholesalers for purposes of regulation of import/exports. Reliable measurements which can indicate that irradiated foods have not received radiation

dose in excess of the legal limits are needed by regulatory agencies.

Finding of DOPA in irradiated chicken meat may be utilized for the development of suitable PID for meats.

Accidental exposure of personnel to radiation has occurred in some cases without an adequate OLD being present, accentuating the need for the

development of novel concepts in RTD and PID for such circumstances.

Measurements of the total energy delivered (J) to a patient in radiation therapy would be useful information to a therapist. Possible

presence of unique radiolytic products, URPs, in the urine of irradiated

patients or personnel in space is under investigation.

Achievements

Mechanisms of DNA Damage

1. Reaction mechanisms and distributions of OH radical attack on thymine, uracil and their derivatives were determined by pulse

radiolysis. Reducing radicals were shown to be formed in excess.

On oxidation of these reducing (6-yl) radicals by oxidizing

agents pyrimidine glycols are produced. Mechanisms of the

thymine glycol formation is important for the understanding of

finding of thymine glycol in the urine, which reflects the extent

of damage to DNA. It is hoped that thymine glycol will be used

as an internal dosimeter of exposure to genotoxic agents.

(Jovanovic, Simic)

2. Novel crosslinks and their mechanisms of formation were discovered for sugar-thymine and sugar-phenyl al ani ne, which indicates a possible role of deoxyribose in radiation-induced DNA-protein

crosslinks in cells. Radiation-induced crosslinking of DNA to

proteins has been shown recently to be one of the major effects

of radiation in cells. However, the molecular mechanism and its

biological significance are not known at present. (Farahani,

Karam, Dizdaroglu, Simic)

3. Novel intramolecul ar mechanism of strand break formation was discovered which operates via addition of OH radical to thymine,

T, and subsequent H atom abstraction by the resulting radical,

•T-OH, from a neighboring deoxyribose. The *T-0H radical cannot

abstract H from a sugar to which it is attached. Hence, the

171
Division 536, Technical Activities (cont'd.)

following mechanism has been proposed T-S-P-S-T-OH + T-S-P-S-THOH, since the product THOH has been isolated. These

indirect routes to strand breaks may be of importance in understanding the mechamism of radiation-induced DNA double strand

breaks which is a major cause of deleterious effects of radiation. (Dizdaroglu, Karam, Simic)

Radi oprotecti on

A new role for uric acid, a suggested dietary antioxidant, was discovered. Uric acid was found to be a potent repairing agent

of oxidative damage to DNA bases and as such, may play a significant role in protection against mutation, cancer, aging and radiation injury. Further work is needed to establish its signifi- cance as an endogenous protector of DNA. (Jovanovic, Simic)

Chemical Dosimetry

1. Important advances in the development of OWG dosimeters have

contributed to: (a) commercialization of a first OWG food irradiation dosimeter; (b) development and testing of an emergency

personnel and environmental dosimeter. These dosimeters have

been shown to be suitable for the measurement of 1-100 rad. They

also promise further increase in sensitivity for application to

the <1 rad region. Their application to the 30-100 krad region

in food irradiation processing is also of interest because of

lack of suitable dosimeters for that range of dose and the

approval of FDA up to 100 krad for food irradiation.

(McLaughlin, Radak)

2. Several new organic detectors of radiation have been shown to be

suitable for dosimetry applied to biology and medicine. These

organic systems have sufficient accuracy and reproducibi 1 i ty, as well as energy absorption properties, of bio-systems. Energy

dependence characteri sties for photon energies down to a few keV

demonstrate their applicability to dose measurements in muscle,

bone, and adipose tissue. (McLaughlin)

3. Mechanisms of radiation-induced color changes of leuco dyes in

radiochromic dosimeters, not understood so far, have been resolved by pulse radiolytic investigation of model dye systems. It was shown that solvated electrons eliminate cyanide from a leuco

form of a dye (no color) in the first step. The resulting dye

radical is then oxidized to a carbocation (colored) by oxygen.

(AlSheikhly, McLaughlin)

172
Division 536, Technical Activities (cont'd.)

4. DOPA has been found in irradiated chicken meat, which normally

contains much lower levels. This radiolytic product originates

from an OH radical reaction with tyrosine, one of the 20 most common amino acids in proteins. The product can be utilized for

post-irradiation dosimetry in meats. At present, methodology to

tell whether meat has been irradiated does not exist.

Availability of such a method is of great importance in regulating irradiation processing of meats (pork in particular) and

prevention of illegal importation of irradiated shrimp, frog

legs, etc. (Dizdaroglu, Simic)

Conferences (M. G. Simic)

Major international conferences on the mechanisms of radiation and

free-radical damage to bio-systems and their repair have been organized

and new ones are in the preliminary organizational stages. The goal of

these conferences has been to promote preventive aspects and protection

from hazardous agents at the molecular level. In that series are the

following conferences: (1) Autoxidation in Foods and Biological Systems,

1979; (2) 1st Conference on Radioprotectors and Anticarcinogenesis, 1982;

(3) Mechanisms of DNA Damage and Repair. Implications for Carcinogenesis

and Risk Assessment, 1985; (4) 2nd Conference on Anticarcinogenesis and

Radiation Protection, 1986; and (5) IV International Congress on Oxygen

Radicals, 1987.

III. Neutron Measurements and Research Group

This group is concerned with measurements of neutron interactions

which depend strongly on the neutrons' energy. The interactions include

both nuclear and molecular effects and require neutron spectroscopic capability from 0.005 eV to 50 MeV —over ten decades of energy. The largest

program is devoted to a continuing international effort to push the accu- racy of reference neutron cross sections into the ±1 percent (1 SD) range.

Other programs are concerned with the development and exploration of analytical techniques based on the unique features of the neutron's interaction with matter. Both the standards and analytical studies require a significant component of fundamental neutron research. The NBS facilities

used are the 100-MeV linac, 3-MV positive-ion Van de Graaff, and nuclear

reactor. A list of the group's technical activities follows.

Absolute Measurements of the 235 U(n,f) Cross Section for Neutron Energies

from 0.3 to 3 MeV (A. D. Carlson, J. W. Behrens, R. G. Johnson, &

G. F. Cooper)

Measurements of the 235 U neutron fission cross section have been made

at the NBS neutron time-of-fl i ght facility. The neutron flux was measured

at the 200-m end station with a Black Neutron Detector. The 235 U fission

reaction rate was determined with a fission chamber located on the same beam line at 69 m from the neutron target. The data have been analyzed

173
Division 536, Technical Activities (cont'd.)

and the results were given at the recent IAEA Advisory Group Meeting. The

final data including extensive information on correlations and uncertainties are being used in the upcoming ENDF/B-VI evaluation of the neutron cross section standards. In the 0. 3-1.2 MeV region the present measurements are generally in good agreement with two earlier NBS measurements

using the linac and Van de Graaff facilities; however, the present data

are systematically slightly lower than the previous measurements . All

three data sets are lower than the ENDF/B-V evaluation. The present mea- surements are also lower than the evaluation in the higher end of the

energy region.

Application of the Dual Thin Scintillator Neutron Flux Monitor in a 235 U(n,f) Cross Section Measurement (M. S. Dias, R. G. Johnson,

A. D. Carlson, & 0. A. Wasson)

A measurement of the 235 U(n,f) cross section in the 1.0 to 6.0 MeV

range has been made at the same NBS neutron time-of-f 1

i ght facility as the

preceding measurement. The dual thin scintillator (DTS) neutron detector

was used as the flux monitor. This detector was placed in the 200-m end

station. The 235 U fission reaction rate was determined using a fission

chamber containing deposits of ~ 100 ug/cm2 located on the same beam line

at 69 m from the source. The data from this measurement have been analyzed and the results have been reported in a paper at the recent IAEA

Advisory Group Meeting.

Since the present measurement was intended primarily as a test of the

DTS detector as a flux monitor, only moderate energy resolution (~ 10

percent was planned. The statistical precision is 1.0 percent at 1.3 MeV

and 2.1 percent at 6.0 MeV. In the region of overlap there is excellent

agreement between the present measurement and the measurement using the

Black Detector data. While the overall agreement with ENDF/B-V is good

the data tend to be lower than the evaluation below 2.5 MeV and higher

than the evaluation between 2.5 and 3.5 MeV.

Measurements of the Ratio of the 1Q B(n,g) 7 Li to 6 Li(n,t) 4 He Cross Sections

in the eV Energy Region (A. D. Carlson)

A previous measurement at NBS of the 10 B(n,a) to 6 Li(n,t) cross section ratio was initiated in order to determine if the discrepancy between

two sets of 235 U(n,f) cross section measurements from other laboratories

was a result of the detectors used for determining the neutron flux. Our

previous measurement did not explain the 235 U discrepancy but did show an apparent difference of 1-2 percent below 20 eV in the 1

0

B

/

6 L i ratio compared with the ENDF/B-V cross sections. The present measurements were made in order to further study the effect.

174
Division 536, Technical Activities (cont'd.)

The present experiment employs essentially the same equipment and

setup as was used in our previous work. The 10 B(n,a) and 6 Li(n,t) rates

were measured with a 10 B plated ionization chamber and a thin natural

lithium glass detector located at the 20-m station of the NBS neutron

time-of-f 1 ight facility. Lower backgrounds were obtained in the present

work through improvements in shielding and the use of a narrower pulse

height window for the 6 Li detector. Additional Rh and Pt beam filters

reduced the systematic error due to the interpolation of the background.

The present measurements agree with the ENDF/B-V evaluations. The previous measurement was probably affected by systematic errors in the background subtraction.

The results of the present study were submitted for publication.

Though this work has been completed, further studies are being performed

with these detectors in order to determine if it is possible to extend the

results to higher neutron energies.

Development of Boron-Uranium Fission Chamber for Cross Section

Measurements in the eV Energy Region (R. A. Schrack)

A composite ionization fission chamber was designed, constructed, and

initial measurements have been made. The device incorporates both 10 B and

235 U foils intermixed in the same chamber filled with lj atmosphere of P-10

gas. Computer simulations of pulse height distribution have been verified

by experimental measurements. Filters of cobalt, manganese, gold, rhodium, and platinum have been used to measure the background for the boron

and uranium detector systems. Preliminary results indicate about a 1 percent background that is independent of energy for both systems.

Multiple scattering, self-shielding, and backscatteri ng calculations

have been made and indicate effects less than 1 percent. A relative measurement of the 23

5

U/ 1

0

B cross-section ratio is underway that will cover

the energy range from thermal to 1000 eV. Foil uniformity and total mass,

counts below threshold, and detector efficiency will then not affect the

precison of the measurement. Work is now continuing on preliminary tests

and the required two-parameter, two-experiment data acquisition system.

Because of the large energy region spanned by the experiment it will be

necessary to incorporate an "accordion" system that will have several

changes in energy resolution over the range covered.

Development of a Standard 2.5 MeV Neutron Beam (K. C. Duvall)

The recent purchase of a 100 keV, 0.5 mA ion generator will permit

the development of a standard 2.5 MeV neutron beam. The neutron source

will be produced by the D(d,n) 3 He reaction in which the output will be

determined by associated particle measurement. The high accuracy measurement capability of the time-correl ated associated particle (TCAP) method

175
Division 536, Technical Activities (cont'd.)

will be utilized to carry out standard cross section measurments to accu- racies of the order of ±1 percent. The neutron beam facility will be used

to measure the 235 U(n,f), 239 Pu(n,f), 197 Au(n,y), and 3 He(n,p) cross sec- tions at 2.5 MeV. It is intended that this measurement effort contribute

significantly to the establishment of 2.5 MeV as a high accuracy normalization point between the spot energies of 14 MeV and thermal.

Analysis of the Effect of Random Events on the 14 MeV 235 U(n,f) Cross

Section Standard Measurement (0. A. Wasson, A. D. Carlson, &

K. C. Duval 1

)

The most accurate measurements of the 235 U(n,f) cross section at 14

MeV neutron energy have used the Time-Correlated Associated-Particle

Technique (TCAP) with the T(d,n) 4 He reaction. These measurements, using

three independent 235 U mass standards, are in excellent agreement (1

percent)

.

However, it has recently been suggested that some of these published mea- surements should be changed because of the effect of random events on the

coincidence timing. Since the NBS conditions differed from those encountered in many other similar experiments, a detailed analysis of the NBS

experiment and the electronic suppression of coincidence losses due to

random events was performed. The unique combination of electronic components incorporated in the experiment eliminated the effect of losses due

to random events in the timing analyzer. There is, thus, no correction to

apply and no change in the published value of the NBS measurement is warranted. This analysis has been submitted for publication.

Development of the Dual Thin Scintillator (DTS) in the Coincidence

Configuration as a Neutron Spectrometer (K. C. Duvall & R. G. Johnson)

The Dual Thin Scintillator (DTS) has been designed and built at the

NBS for use as an absolute neutron flux monitor in the energy range of 1-

20 MeV. The DTS detector consists of two thin, back-to-back plastic scintillators optically separated from each other and independently coupled to

photomultiplier tubes. The detector may be operated in the coincidence

configuration where only simultaneous events in both first and second

scintillator are recorded. The events recorded in the coincidence configuration are due primarily to proton recoils that are produced in the first

scintillator and pass into the second scintillator. The energy distribution of the proton recoils recorded is affected by the range of the recoil

particles and is determined by the angles allowed for path lengths reaching into the second scintillator. The detector pulse height distribution

consists, therefore, of contributions from the more forward scattered,

higher energy proton recoil events and exhibits a more peaked response,

centered at the incident neutron energy. This is a more favorable

response function to be used with spectrum unfolding techniques and

should provide improvement over spectral determinations with conventional

proton recoil response functions.

176
Division 536, Technical Activities (cont'd.)

Neutron Resonance Transmission Analysis for Nondestructive Evaluation of

Proximity Fuzes ( R . G. .Johnson & R. A. Schrack) ~

In collaboration with Harry Diamond Laboratories we have recently

applied the technique of neutron resonance transmission analysis (NRTA) to

nondestructi vely evaluate (NDE) the power supplies of M732 proximity

fuzes. Some of these power supplies, which are simple lead-acid

batteries, were failing when the acid leaked from its ampule into the

normally separate volume containing the lead plates. In addition to the

acid, a buffering agent, methylene bromide, is contained in the ampule.

The NRTA technique was used to detect the presence of bromine (using the

35.8 -eV resonance) in part of the battery containing the lead plates.

Measurements were performed at the NBS neutron time-of-f 1 i ght facility

where the fuze was placed at 5.4 m from the source and the neutron beam

was collimated to a 3.2 cm by 0.7 cm area. Transmitted neutrons were detected at 6.7 m by a

6 Li-glass scintillator (4.4-cm diameter by 2.5-cm

thick). Originally it was expected that the observation of bromine would

be difficult because only the presence of methylene bromide vapor was anticipated. However, experimental ly a strong bromine resonance was observed in known bad batteries. We found that the methylene bromide was being concentrated because it attacked the plastic case of the battery.

For a full test of the method four cases (32 fuzes) of fuzes were

received from HDL for testing. The condition of the power supplies in

these fuzes was unknown. After testing at NBS the fuzes were returned to

HDL where they were disassembled and checked for leaking power supplies.

Although both false positive and false negative identification of leaking

power supplies were seen in the results, the cause of these problems is

well understood and can be eliminated. The NRTA technique can be a viable

method to screen M732 proximity fuzes.

The final phase in this project was the specification of design

parameters for a portable linac to implement NRTA for screening the M732

fuze stockpile and the identification of vendors for such a linac. The

linac could be moved to the storage locations and fuzes could be examined

at an effective rate of 15-45 seconds per fuze.

Measurement of the NBS Black Neutron Detector Efficiency at 2.3 MeV

(K. C. Duvall, A. D. Carlson, & 0. A Wasson)

The absolute efficiency of the NBS Black Neutron Detector at 2.3 MeV

has been measured using the time-correl ated associated particle method.

Until recently, the NBS Black Neutron Detector had been utilized only in

the limited energy range of 0.2 to 1.2 MeV, where the efficiency determination from Monte Carlo calculations has been verified by experiment. A

result of 0.760 has been obtained for the Black Neutron Detector efficiency at 2.3 MeV with an experimental uncertainty of ±1.2 percent and agrees

well with the Monte Carlo calculated value. The measurement extends the

177
Division 536, Technical Activities (cont'd.)

usefulness of the Black Neutron Detector as an absolute neutron flux monitor to the higher energy region and in fact has been used to measure the

235 U(n,f) cross section from 0.3 to 3.0 MeV. This result has been

publ i shed

.

Detector Development for eV Scattering Spectrometers (R. G. Johnson)

Detector development for resonance detector spectrometers (RDS) to

extend neutron scattering studies to the eV region has continued. In this

technique the energy of the scattered neutron is defined by a low energy

nuclear resonance. Previously the use of a large area planar HPGe

detector which detects the x rays from internal conversion of y rays

following neutron capture was shown to provide good efficiency and good

background rejection. Since in the internal conversion process both an electron and an x ray are emitted, detecting both signals in coincidence

can improve the background rejection. To test this method two thin gold

foils (3-ym thick) were placed between three 1.0-mm thick plastic scintillators. Electrons detected by the plastic scintillator provided a coincidence gate for the HPGe detector.

The results of this initial measurement show that even with this less

than optimum foil and scintillator thicknesses, an improvement of ~ 2.5 in

the signal to background ratio was observed when operating in the coincidence mode as opposed to the non-coincidence mode.

International Intercompari son of Neutron Flux Measurement Capability at

500 keV (A. D. Carlson, R. G. Johnson, & 0. A. Wasson)

A final report on the NBS participation in an international intercomparison of neutron flux measurement capability sponsored by the

Consultative Committee for Ionizing Radiations (CCEMRI) at B I PM has been

prepared and sent to AERE Harwell, the organizing laboratory. This intercomparison which uses a large 235 U fission ionization chamber allowed both

linac and Van de Graaff neutron facilities to be used. The detector

efficiencies measured at 500 keV at the linac and Van de Graaff facilities

at NBS agree well within the 1.7 percent total error for each

measurement

.

Data Acquisition System Improvements (R. G. Johnson)

The first computer system to replace one of our three Harris /5

systems is on order and should be delivered in September. The computer

ordered is a Charles River Data Systems Universe UV2403FT-E which is based

on the Motorola 68000 mi croprocessor on the VME bus. As a replacement

this computer can be expected to provide a factor of ~ 10 improvement in

most aspects of our data acquisition capabilities.

178
Division 536, Technical Activities (cont'd.)

The Neutron Cross Section Standards for the National Evaluated Nuclear

Data File, ENDF/B-V I (A. D. Carlson, W. P. Poenitz (ANL) , G. M. Hale

( LANL ) , and R. W. Peelle (ORNL))

This sixth evaluation effort under the leadership of Carlson is

following a different process than that used for previous versions. The

primary effort is concentrated on a simultaneous evaluation using generalized least squares, R-matrix evaluations and a procedure for combining the

results of these evaluations. The simultaneous evaluation is important to

this process since ratio measurements in addition to shape and absolute

determinations are treated properly. Correlations within and among experimental data sets are also taken into account.

The R-matrix evaluations provide a method which allows charged

particle measurements involving the same compound nuclei ( 7 Li and 11 B) to

be included in the evaluation process. These evaluations also provide a smooth meaningful expression for the energy dependence of the cross

sections. Independent data bases are used in the simultaneous and Rmatrix evaluations. The combining procedure is used to combine the information obtained from these analyses in a proper way to form the final

evaluation and its vari ance-covari ance matrix. The standards being evaluated are 6 U(n,t), 10 B(n,a 1 ),

10 B(n,a), 197 Au(n,y) and 235 U(n,f).

Evaluations for the important reactions 238 U(n,y), 238 U(n,f), and

239 Pu(n,f) are also being performed.

Preliminary results of the evaluation process with overlapping and

non-overlapping data bases have been reported at recent nuclear data meetings. Efforts are now underway to further improve the grouping of the

data bases for the simultaneous and R-matrix analyses. Also a new concept

involving the thermal constants is being implemented. This will allow the

relevant thermal constants to be evaluated simultaneously within the

framework of the standards evaluation.

Efforts have been and continue to be made to handle the various parts

of the evaluation process in a proper and defensible way. Significant

progress has been made but the process is complicated and time consuming.

It is anticipated that final combination results, i.e., adjusted R-matrix

parameters for the lithium and boron cross sections and pointwise values

for the 197 Au(n,y) and 235 U(n,f) cross sections, will be available in

early 1986.

Development of Rutherford Backscatteri ng Facility for Analysis of U09 Samp! es (0. A. Wasson, W. E. Slater, & H. Frederikse)

A Rutherford Backscattering (RBS) facility was established on a new

beam line at the 3-MV positive ion Van de Graaff laboratory. This facility, in collaboration with scientists from the Center for Materials

Science, is being utilized for studies of the areal density distribution

179
Division 536, Technical Activities (cont'd.)

of uranium deposits used in neutron cross section measurements. A versatile scattering chamber with numerous ports, 5 axis goniometer, target

ladder, and solid state detector is in operation. In addition to the

hydrogen and deuterium beam used for neutron production, the accelerator

was modified to produce 1.3 MeV He+ beams with currents as large as 10

microamperes and 5-MeV He2+ beams with currents as large as 100 nanoamperes. The variation in areal density of a 75 cm diameter U02 deposit was measured using a 1 MeV He + beam. The results are in excellent agreement

with those obtained from a-activity measurements.

Profile of U09 Deposits by a-Particle Counting (R. A. Schrack)

Deposits of 235 U in the form of U0 2 on aluminum backing were obtained

from Oak Ridge National Laboratory. The deposits are three inches in

diameter and vary in uniformity. Use of the foils in a fission chamber

being built to measure the 235 U fission cross section requires a knowledge

of the deposit uniformity. Fortunately, the material used to produce the

uranium deposit had a 0.99 percent contribution of 234 U. This isotope has

a relatively high probability of decay by a-particle emission. Assuming

that there is no isotopic separation during deposition, the 234 U distribution can be measured by a-particle detection to determine the 235 U distribution. A collimator system for the a-particle detector was designed and

its efficiency and response function determined by a Monte Carlo program.

The results from the measurements are in good agreement with those from

Rutherford Backscattering and show that the density of the deposit drops

by at least 10 percent from the center to the edge. This variation is

acceptable if the fission chamber is to be used for relative measurements

but will necessitate careful measurement and corrections for absolute

cross section measurements

.

Neutron Resonance Transmission Analysis of Reactor Fuel Samples

(J. Behrens, R. Johnson, and R. Schrack)

Neutron resonance transmission analysis has been used to measure the

isotopic content of fresh and spent nuclear reactor fuel samples. Our

final results have been published.

He-3 Gas Scintillation Counter (J. W. Behrens)

The NBS 3 He gas scintillation counter is a dual -windowed, cylindrical

gas cell with a pair of RCA 8850 photomultipliers viewing a gas mixture of

48 percent 3 He/52 percent Xe (nitrogen 30 ppm). The pyrex glass windows

are coated with 30 ugm/cm2 DPS wavelength shifter. The stainless steel

cylindrical section of the cell is coated with a 1000 A layer of aluminum.

In November 1983 this counter was pressurized to 30 psia. Since that

time, it has been thoroughly studied at the NBS linac. Van de Graaff, and

Reactor facilities.

180
Division 536, Technical Activities (cont'd.)

In the published literature on gas scintillation counters, researchers usually recommend continuous gas purification to reduce degradation of

the ultraviolet light output, due to trace impurities such as oxygen.

Even with gas purification, they warn that one can reasonably expect only

several months of stable operation before significant degradation starts.

Amazingly, our detector has been working for over 21 months with no significant loss (<_ 5 percent) in light output and it has no continuous gas

purification. We measure our counter's light output relative to the single photoelectron peak from the matched photomultipliers. We have clearly

found a design which can ensure stable operation over a reasonable time

period without the need for a costly and perhaps complex continuous gas

purification system. This greatly simplifies the detector's design and

significantly reduces its cost.

The energy resolution of our present design, however, must be

improved to ensure accurate subtraction of the 3 He-recoil pulse height

spectrum from the total pulse height spectrum measured. Computer modeling

using the Monte Carlo technique will help determine the shapes of the 3 Herecoil spectrum and the desired 3 He(n,p)T spectrum. To improve the energy

resolution of the detector, we are incorporating into our design concepts

from the "Gas Proportional Scintillation Counter" (GPSC). GPSCs typically

use an applied electric field to enhance light output by accelerating the

electrons from the initial ionization. Light output can be magnified by

several orders of magnitude and at the same time, the energy resolution

can be improved to rival or even better that from a conventional gas

proportional counter (aE/E^ 10 percent). From the GPSC, fast timing is

obtained from the "prompt" scintillation pulse; whereas, improved energy

resolution is obtained from the slower "secondary" scintillation pulse.

Work is presently in progress on i ncorporati ng GPSC concepts into our design and on refining our computer codes to calculate the shapes of the

3 He-recoil and 3 He(n,p)T pulse-height spectra. We feel confident in our choices of 30 ugm/cm2 DPS evaporated only on the glass windows of the cell

and of the RCA 8850 photomultiplier. Our design can ensure stable operation over reasonable time periods without the need for continuous gas

purification.

Guest Scientist at Centre d' Etudes de Bruyeres-1 e-Chatel , France

(J. W. Behrens)

J. W. Behrens returned to NBS on January 1, 1985 after completing a one year assignment as a guest scientist at Centre d' Etudes de Bruy&resle-Ch<!tel, France. During his assignment he participated in "Cold

Fragmentation" fission measurements and in studies of the fission cross

section systematics of the actinides for MeV neutrons. Publication of

both of these investigations is in progress.

181
Divi sion 536, Technical Activities (cont'd.)

The evolution of a fissioning nucleus from saddle point to scission

is perhaps the least known stage of nuclear fission at low energy. The

cold configuration is particularly interesting to study because it makes

available to experiment the primary fragmentation, as the fragment excitation energy is low enough that no neutrons are emitted. In the present

measurements, we investigated cold fragmentation in the thermal neutroninduced fission of 235 U, i.e., 236 U, to test the fission dynamics calculation and to contribute to the knowledge of the even-odd effect and of the

maximum total fragment kinetic energy for a given fragmentation.

In addition to obtaining nuclear data from measurement and theory,

one may also rely on the study of systematic trends in nuclear parameters

which are accurately known to infer these parameters for nuclides which

are not accurately known, often because they are difficult to measure.

The present study has the goal of inferring a^fvalues to an accuracy of

within ±10 percent for selected, short-lived (t 1/2 < 100 years) actinides

from trends observed in a„f values for their longer-lived, measured neighbors. Results for a total of over 40 isotopes of the uraniums, neptuniums, and plutoniums have now been completed. Extension of these trends

to the transplutoniums, however, yields inferred values which significantly overpredict the fission cross section. This overprediction is primarily caused by the change in the systematics of the inner fission barrier

height near compound nucleus neutron number 146.

The Development of a 6-to-7 MeV Photon Field for Instrument Calibration

(K. C. Duval 1

)

Improvements in the 6 to 7 MeV photon source characteristics and

measurement capabilities continue. The proton incident beam energy has

been increased to 2.7 MeV which has resulted in an increase of at least a factor of two in the high energy photon yield. The increased photon yield

is expected to allow absorbed dose measurements to be carried out with a small ion chamber as well as with thermoluminescent dosimeters. Also,

analysis codes used in unfolding Nal pulse-height data have been transferred and implemented on the new NBS central computing system. The spectrum

unfolding analysis, which requires a substantial allocation of memory,

benefits from the increased computing capability of the new central

computer

.

Conceptual Design of an Induction Linac for Neutron Research

(R. G. Johnson)

The induction linac originally discussed in the recent Neutron and

High-LET Radiation Program Analysis report has been redesigned to take

advantage of recent developments in induction accelerator technology. The

major question in the original design concerned the design of the pulse

forming network. Since that time, the work on magnetic pulse compression

182
Division 536, Technical Activities (cont'd.)

at Lawrence Livermore National Laboratory has been successfully completed.

Incorporating this work in the design of an induction linac settled this

critical question and provided further simplification in the design of

induction modules. A report on the improved design was presented at the

International Conference on Nuclear Data for Basic and Applied Science

(May 13-17, 1985, Santa Fe, NM)

.

Measurement of the Isotopic Composition of an Uranium Sample

(R. A. Schrack and 0. A. Wasson)

The isotopic composition of an uranium sample for use in a crystal

spectrometer at the University of Alberta was measured by use of neutron

resonance radiography at the linac time-of-f 1

i ght facility. The sample

was found to consist of depleted uranium with a 235 U composition of 0.15

percent.

IV. Neutron Dosimetry Group

This group is engaged in the development and application of standard

and reference neutron fields as permanent facilities for neutron dosimetry

standardization, for neutron detector calibrations, and for reaction rate cross section measurements. Strong interactions with outside organizations, both in the federal and private sector, are important programmatic

characteristics.

Neutron Personnel Dosimetry (R. B. Schwartz)

Remmeter calibrations were carried out at the Cf Irradiation Facility

for a dozen or more organizations in the public and private sector including nuclear utilities and three branches of the military.

The reactor filtered beams at 24 keV and 144 keV were used to test a new concept in remmeter design, developed at the Los Alamos National

Laboratory. The new design is based on a two-inch diameter tissue equivalent proportional counter with an attached package of appropriate electronics. Calculations and preliminary measurements at Los Alamos indicated that this hand held instrument should be accurate to within ± 20 percent, as opposed to a factor of two (or more!) for conventional remmeters.

In addition, the new instrument is smaller and less costly. NBS provided

Los Alamos scientists with a needed measurement in the 20- to 30-keV

region to check a calculated cut-off in response. The 24-keV beam is

ideal for this response check. The results were more than satisfactory:

our calibration agreed with design calculation to within 2 percent. The

Los Alamos scientists, encouraged by these results, will proceed to have

the instrument developed commercially.

183
Division 536, Technical Activities (cont'd.)

A new line of research consists of measurements with a "tissue-equivalent proportional counter." This is a counter whose gas filling has

approximately the same chemical constituents as biological tissue. By

filling the counter to an appropriate pressure, the counter will simulate

a tissue sphere about one micron in diameter. The spectra, when appropriately analyzed, can be used to determine dose and dose equivalent as a function of the energy deposited in tissue.

In the Technical Activities report last year, preliminary measurements made at the 144 keV beam were discussed. These measurements have

been repeated with lower noise electronics and in addition new measurements were made at the 24 and the 2 keV beams. The 144 keV results are in

good agreement with calculated spectra, and with other measurements. The

2 and 24 keV measurements are internally consistent, but there are no other results with which to compare.

Computer programs have been written in BASIC for these analyses. In previous measurements of the 252 Cf microdosimetric spectrum, electronic

noise was a limitation at lineal energies below about 1 keV/ym. By

increasing gas gain in the proportional counter and making appropriate

changes in the electronics, the lower limit has been reduced to about 0.15

keV/ym.

The neutron dosimetry support program with the Armed Forces

Radiobiological Research Institute continues in high gear. Highlights

of this effort include: (1) on site measurements in the TRIGA reactor

exposure room which led to a decision to replace tissue equivalent ion

chambers with NBS-type double fission chambers as the primary irradiation

monitor; (2) final design of a neutron check source is finished and fabrication at Reactor Experiments, Inc. has begun; (3) long-standing "polarity

effects" (i.e. ion chamber currents dependent upon high-voltage polarity)

have been reduced by a factor of five by changing cable type, length and

routing; and (4) activation detector measurements in the TRIGA exposure

room established spatial gradients and room return for low and high energy

neutrons

.

In support of the AFRRI integral dosimetry measurements, and of

general interest for dosimetry standardization, an effort continues to

establish a dosimetry analysis scheme which performs few-group spectrum

adjustments of integral detector data by minimizing the sum of squares of

differences between observed and calculated detector reaction probabilities. The resulting SPAD analysis code provides a basis for obtaining

neutron exposure parameters (e.g. fluence or kerma) from individual integral detector respones without arbitrary spectrum interpolation. The

analysis allows major and minor error sources to be distinguished and

propagated. The procedures has been applied to activation detector data

obtained by a dosimetry lab under contract to AFRRI.

184
Division 536, Technical Activities (cont'd.)

Dosimetry for Materials Performance Assessment (E. D. McGarry &

J. A. Grundl)

As reported last year, the main focus of materials performance dosimetry is associated with the preparation and evaluation of documentation

describing reactor pressure vessel (RPV) mock-up experiments at ORNL.

Experimental characteri zat ion of these neutron fields rests largely upon

neutron reaction probability measurements that were referenced to the

fission neutron standard fields at NBS.

More emphasis is now being placed on the industry option of making

pressure vessel surveillance dosimetry measurements outside rather than

inside of the vessels of commerical power reactors. The following paragraphs identify the most significant efforts and related NBS involvements

carried out under contract with the Nuclear Regulatory Commission (NRC).

The main objective of the NBS effort has been to achieve benchmark referencing of dosimetry measurements through the distribution of Certified

Fluence Standards. These standards are threshold and fission-type neutron

sensors irradiated in a standard neutron field to a well-defined neutron

fluence.

Special ex-vessel (cavity) dosimetry was installed in the Maine

Yankee Reactor for the first low-leakage fuel cycle. This dosimetry has

been removed for analyses by Westinghouse Nuclear Technology Division

(WNTD) and by Combustion Engineering (CE). NBS personnel were on site as consultants to the Maine Yankee Atomic Power Company during the removal

and shipment of the neutron dosimeters and have, subsequently, distributed

certified fluence standards to benchmark reference the radioactivity

counting of the dosimeters. The fluence standards were prepared in the

NBS Standard 235 U Fission Neutron Field.

Very similar measurements, and NBS participation, are continuing

in the H.B. Robinson Reactor operated by the Carolina Power and Light

Company.

Cavity dosimetry research has been going on for several years in

the Arkansas Nuclear One, Units I and II Reactors and in the McGuire I Reactor with NRC and Electric Power Research Institute (EPRI) support.

NBS has supplied certified fluence standards for radiometric counter calibrations, and special paired uranium detectors for measurement of the fast

neutron fluences in a number of the experiments. A total of 56 such

fluence standards have been distributed, to date.

Florida Power and Light Company is now responsible for coordination

of the WNTD, NRC and NBS activities involved with cavity dosimetry for the

Turkey Point 3 Reactor. Therein, the NBS paired uranium detectors and

other radiometric dosimeters are employed to validate the use of solid

state track recorders (recording fission tracks in mica as a means of fast

185
Division 536, Technical Activities (cont'd.)

neutron dosimetry) in commercial reactor cavities. Finally, Babcock and

Wilcox, has separately announced plans recently for a major benchmark

experiment to validate SSTR dosimetry in the Davis Bessie Reactor starting

in FY 86. Dosimetry standardization via NBS will be part of this

program.

Integral Cross Section Measurements (D. M. Gilliam & G. P. Lamaze)

A number of integral reaction rate cross sections were reported out

in FY-85. In addition, the unusually large discrepancy between observed

and predicted helium production cross sections were examined for a number

of reactor physics benchmarks.

(1) In the Cavity Fission Source Irradiation Facility at the Belgian

CEN/ SCK Laboratory, a series of cross section measurements were carried

out in which the neutron fluence rate was determined by a transfer measurement from the known fluence rate in the vicinity of a calibrated 252 Cf

neutron source at NBS. The absolute calibration of the 252 Cf neutron

source was established by means of a manganese bath intercompari son with

the standard neutron source NBS-I. Fission spectrum cross sections have

been obtained for fission in 238 U, 235 U, 233 U, 239 Pu, 240 Pu, 237 Np, and

232 Th. Also included in the measurements were 115 In(n,n‘) and 58 Ni(n,p) cross sections. The 115 In and 58 Ni cross sections, which are important

for reactor dosimetry standardization disagree with the ENDF/B-V tabulations by about (5.9 ± 2.1) percent and (6.2 ± 2.4) percent, respecti vely

.

These discrepancies show the importance of using standard neutron fields

as benchmarks for dosimetry measurements when accuracies of < 5 percent

are sought. Similarly, the fission cross section ratio for 235 U(n,f)

relative to 239 Pu(n,f), an important quantity for reactor physics, was measured to an accuracy of ± 1.0 percent at CEN/SCK. The value of this

ratio obtained from calculation with ENDF/B-V data differs from the experimental value by 4.5 percent.

(2) The spectrum-integrated helium generation cross sections for

6

Li

and 10 B have been determined for the NBS Intermedi ate-Energy Standard

Neutron Field (ISNF). Helium concentrations were measured by precise

high- sensitivity gas-mass spectrometric analysis of vaporized small

encapsulated and unencapsulated crystalline samples of natural boron,

enriched 10 B, and enriched 6 L i F . The cross section results are consistent with previously obtained data for other reactor physics benchmarks at

LANL (Los Alamos), INEL (Idaho), and SCK/CEN (Belgium). A comparison of

the ISNF measurement with cross sections calculated using the ENDF/B-V

file show a discrepancy of 10 percent for 10 B and 5 percent for 6 Li. The

total error associated with this extraordi nary discrepancy, including the

ISNF spectrum uncertainty is ± 3.6 percent for 10 B and ± 3.1 percent for

6 Li

.

186
Division 536, Technical Activities (cont'd.)

Of the ten helium production cross sections for 10 B and 6 Li reported

for five reactor physics benchmarks, ENDF/B-V underpredicts nine of the

ten by two to five times the experimental errors. Relevant measurements

with enriched boron and lithium samples were performed at four different

laboratories over a 10-year period. Helium production was determined at

Rockwell International by means of the HAFM method and neutron fluences

for the required irradiations were derived from NBS fission chamber measurements. A paper was presented at the Sante Fe Nuclear Data Conference

which evaluated these neutron fluence assignments and where necessary

adjusted them to be consistent and traceable to the fast-neutron fluence

scale associated with the NBS 252 Cf Fission Neutron Irradiation Facility.

Abridged remarks from the paper regarding these discrepancies between

calculation and experiment are as follows:

• The C/E discrepancies in a(n,He) for 10 B in five very different reactor physics benchmarks are consistent as well as large: average C/E

= 0.88 ± 0.03. This suggests serious errors, in some combination of

the He production determination, the neutron fluence assignment, the

He production cross section, and/or a common bias in the benchmark

spectrum calculations.

® Notable C/E discrepancies exist for other reactions with well-studied

cross sections in two of the benchmarks for which neutron transport

in uranium is important:

• Neutron transport in ISNF, which does not involve uranium, is largely

determined by the kinematics of scattering in carbon, and below

0.1 MeV by neutron absorption in 10 B: Much 1 arger uncertainties than

can be reasonably assigned to these processes would be required to

bring the associated 19 B and 6 Li reaction cross section errors to

within 1 s.d. of the reported C/E ratios.

• If a spectrum error below 0.1 MeV is postulated in ISNF it must be

attributed to a

10 B cross section error and as such is in a direction

that will not allow the calculated integral cross section for

10 B(n,He) in ISNF to change by more than about 50 percent of any

corresponding 10 B cross section error.

(3) A long series of experiments in which the absolute fission crosssections of 2 3 8 U , 238 U and 239 Pu for 252 Cf spontaneous fission neutrons

were determined is complete. The absolute cross section for 235 U is the

basis for all integral fission cross section measurements in NBS standard

neutron fields and is recognized by the CSEWG subcommittee on standards as

a basic normalization measurement for the 235 U fission cross section. The

NBS results contain two notable disagreements with ENDF/B-V, the cross

187
Division 536, Technical Activities (cont'd.)

section file used for almost all design and operations calculation in

nuclear technology: The C/E ratio for 238 U is 1.057 ± .017 and for

239 Pu/ 235 U C/E is 0.964 ± 0.008. Some unique features of the measurement

are as fol lows:

• The 252 Cf source employed for the measurements has been calibrated

repeatedly (5 times between 1979 and 1984) at the NBS Manganous

Sulfate Bath Facility against the National Standard Ra-Be photoneutron source, NBS-1. The precision of the five measurements as determined by a least-squares fit to a 2.645-year half-life of 252 Cf

is ± 0.5 percent. The presently assigned neutron emission rate

uncertainty of NBS-I is ± 0.85 percent leading to a total 252 Cf

neutron source strength uncertainty of ± 1.1 percent.

• The measurement of distance between fission chambers placed on opposite sides of the source (10 cm) was performed with a computer con- trolled digital cathetometer fitted with a piezoelectric sensor which

operated to a precision of better than ± 0.003 cm.

• Monte Carlo and analytical calculations provided corrections for

neutron scattering in the source capsule, in the fission chambers,

its support structure, and in the fissionable deposit backings.

Neutron return from the walls and floor of the NBS 252 Cf Irradiation

Facility were investigated in a separate experiment and published

separately.

Neutron Source Strength Calibration Facility (E. D. McGarry)

Five neutron sources were calibrated for outside customers at the

Manganous-Sulfate Bath Facility. Together with in-house requirements

including the 235 U cross section measurements just described, a total of

26 individual neutron source determinations were performed. A report of

the international neutron source strength i ntercompar i son described in

last years report has been completed by the National Physical Laboratory

in England. NBS determinations were inside the uncertainty band of the

world average.

The NBS bath facility for neutron source calibration at NBS has been in

operation for 20 years. For the last eight years neutron sources with

emission rates of up to 10 10 n/s have been calibrated to an accuracy of

approximately 1.2 percent. An upgrading of the facility to provide more efficient operation and improved source handling capabilities is moving

ahead full bore.

188
division 536, Technical Activities (cont'd.)

Improvements in Fluence Measurements in the NBS Cavity Fission Source and

Intercal ibration with the Belgian Cavity Fission Source (G. P. Lamaze &

J. A. Grundl)

International intercal ibration of standard neutron fields is important for establishing absolute accuracies of neutron fluences and reaction

rates. A fluence transfer via the 239 Pu(n,f) reaction was made from the

252 Cf source at NBS to the Belgian cavity fission source and then back to

the NBS cavity fission source. The diameter of the MOL cavity in the BR1

Reactor, Mol, Belgium is larger than that of the NBS cavity, resulting in

a smaller correction for reflected neutrons. It also allows a fission

chamber to be operated within the source. An earlier independent calibration of the Belgian fission source was confirmed by NBS and the calibration of the U.S. 235 U Standard Neutron Field was reconfirmed. This new fluence transfer procedure resulted in an overall reduction in the uncer- tainties of fission neutron fluence measurements at NBS. All of this work

as well as the cross sections described under (1) above was reported at

the Fifth ASTM-EURATOM Symposium on Reactor Dosimetry in Geesthacht,

Germany (Nov. 1984).

Neutron Driven Gamma Ray Field (J. A. Grundl)

In cooperation with two European laboratories and the Univ. of

Virginia, a neutron driven gamma-ray field has been constructed to operate

in the NBSR thermal column cavity. The main component of the system is a cadmium cylinder which is exposed to a thermal neutron fluence rate of 3 E 11 n/cm2

s giving rise to a cadmium capture gamma-ray fluence rate of about

2 E 11 photons/cm2

s at the center of the cylinder. This corresponds to a dose rate of close to one megarad/h. The gamma ray field strength is

determined by two methods: measurement of activation from gold foils

placed on the cadmium surface, and measurement of Cd - 1 15 activity induced

in the cadmium cylinder.

The cadmium cylinder can be enclosed in a sheath of lithium-6 loaded

glass to determine the background of gamma rays from the core and from

neutron capture in the surrounding graphite. An iron cylinder, which fits

around the lithium glass, has been constructed as an alternate source of

iron capture gamma rays in known geometry.

First application of the neutron driven gamma ray field is a measurement of photofission rates in 238 U, 232 Th, and 237 Np and photon activation

rates, in indium. Photofission due to gamma background in the facility is

presently estimated to be 7 percent of the primary gammas from the cadmium

source.

Smaller Projects . (1) The neutron dosimetry group has assisted physicists

from the Quantum Metrology Group and the Los Alamos National Laboratory in

setting up a neutron lifetime experiment at the reactor. This experiment

189
Division 536, Technical Activities (cont'd.)

involves absolute beam intensity measurements based on 6 Li total absorption in a detector/cal orimeter and in a fission ionization chamber using

deposits from the NBS collection of fissionable Isotopes Mass Standards.

(2) The Nb(n,n') threshold activation reaction cross section will be

measured for 23 ^U fission spectrum neutrons in a cooperative program with

Prof. Tom Williamson of the University of Virginia. This experiment will

entail an unusually long cavity fission source irradiation with attendant

problems of handling hot fission disks. The Nb(n,n') reaction is attractive for dosimetry because of its long half-life (16 y) and low response

threshold. Because of the long half-life the energy dependence of the

reaction cross section is poorly known and therefore the fission spectrum

integrated cross section is especially valuable. (3) The development of a new mega-gray gamma dosimeter was initiated this year. Crystals of 7 L i F

,

originally investigated by CRR's Bill McLaughlin have been exposed to

mixed gamma and neutron fields to ascertain their ability to respond

selectively to gammas rather than neutrons, an unusual property for any

dosimeter. Results are promising, sufficiently so that we have received

funding for the "LiF chip" investigation from the Nuclear Power Division

of Babcock & Wilcox.

V. Radioactivity Group

Introducti on

During this period there has been an emphasis on technique or instrument development within the Group. In two cases the result may be. the

demonstration of techniques of broad significance for radioactivity mea- surements; in others the capabilities of Group members have been focused

on other-agency problems of immediate concern. Our traditional measurement techniques are also now better instrumented.

A wider distribution of activity calibrations developed at NBS was

also achieved, with more traceability exercises testing the measuring

ability of key 1 aboratories. A major nuclear pharmacy organization with

over 50 distribution centers joined the AIF radiopharmaceutical program.

The pertinence of the form of NBS and commercial reference materials to

the required measurement of radi opharmaceutical s in injection syringes was investigated. Chemical problems encountered in environmental radioactivity monitoring were probed.

These, and other major activities, are discussed in the sections that

follow.

190
Division 536, Technical Activities (cont'd.)

Distribution of Radioactivity Standard Reference Materials (SRMs) and

Measurement Services

The following table sumarizes explicit interactions which propagated

basic NBS activity calibrations between August 1, 1984 and July 31, 1985.

Radioactivity SRMs distributed 709

SRMs under the AIF program

for nuclear medicine 294

Scheduled Calibrations 41

Special Measurements 80

Traceability exercises

including EPA, FDA, NRC,

and commerical firms 133

The traceability exercises carried out with the regulatory agencies,

radiopharmaceutical manuf acturers, and suppliers of commerical reference

materials test the ability of a laboratory to supply an activity value for

a sample of a radionuclide before the NBS calibration is known. The exercises do not, except in special cases or by inference, test or investigate

the general qual i ty-control procedures within the laboratory, which would

be a much more ambitious undertaking.

Urani um-Analysis Discrepancies in Natural -Matri x SRMs (K. G. W. Inn)

We have been confronted with several radiochemical challenges during

the production of environmental-level radi oacti vi ty SRMs. Recently we have investigated an apparent discrepancy in the uranium data set from

assays of SRM 4353 (Rocky Flats Soil-1) and SRM 4350B (River Sediment).

The difference appeared to be on the order of twenty percent between sample pretreatment methods. We have made recent advances in understanding

the nature of the chemical problem which was biasing some of the reported

data. Some laboratories were requested to perform additional analyses; x- ray diffraction and emission spectrometry were used to assay residual

materials after corrosive acid treatment of the sample; and alternative

dissolution radiochemical methods were used to evaluate the residual

materials for excess uranium. The results appear to support the hypothesis that there is a minor mineral fraction with high specific activity of

uranium in these SRMs which resist corrosive acid treatment. We tentatively ascribe the discrepanices in the uranium data set to the inability

to equilibrate chemical yield monitors with the samples.

191
Division 536, Technical Activities (cont'd.)

Xenon-Isomer Electron Spectrometer (F. J. Schima, A. T. Hirshfeld, &

D. D. Hoppes)

Gamma-ray spectrometry can be used to detect moderately low levels of

133 Xe or 135 Xe in a gas sample, but the large internal conversion in the

decays of 131m Xe and 133m Xe makes this method insensitive for these

isomers. In order to select and measure the i nternal -conversion electrons

from these decays, we have constructed trial systems in which xenon is

condensed on the surface of two closely spaced 450 mm2

, 500-u-thick

silicon surf ace-barri er detectors. The large detector areas minimize

source scattering, and the proximity of a second detector reduces the

effect of backscatteri ng.

The cryostat head fits inside the well of a Nal(Tl) detector. A

beta-particle coincidence requirement can be used to greatly reduce the

background for the gamma-ray spectrometer measuring the ground-state

decays, while an ant i -coi nci dence requirement with all photons above x rays detected in the Nal(Tl) reduces the environmental and beta-spectrum

background for the conversion electrons.

Despite these techniques, the electron background remained about 0.05

cs” 1 in the pertinent energy region in the first two systems constructed.

A careful investigation of construction materials with a low-level betaray counting system revealed that the mounting rings for the surfacebarrier detectors could be making a major contribution. A search for

alternate materials led to the use of a special epoxy, and trial detectors

constructed with rings prepared here from castings of this epoxy have

operated successfully with reduced background.

A cryostat redesign minimizes outgassing, and thermal radiation

input. The new system is under construction, and optimal analysis

programs are being developed.

Large-Area Source Calibration Technique (J. M. R. Hutchinson)

A program to develop traceability of the U.S. Air Force alphaparticle field measurements has been underway. The USAF uses surface

monitors (Radiac Calibrators) which are calibrated with UDM-7 large-area

239 P sources. Because no existing counters were large enough to measure

the UDM-7' s, the first year of the project has been devoted to designing

and setting up two large area counters - approximately 12-in by 14-in in

sensitive area. One of the counters is an i nternal -source proportional

flow counter and the other a similar but external -source counter.

Both counters are adapted from commercial counters of German design.

The response as a function of various relevant parameters -- source

position, voltage, amplifier gain -- was tested extensively. Values of

these parameters were found that would give suitable system characteristics to permit measurement of the UDM-7 's to the required accuracy.

192
Division 536, Technical Activities (cont'd.)

The UDM-7's, which are electrically nonconducting, cannot be inserted

directly into the internal counter. The calibration procedure makes use

of a specially prepared conducting large-area source which is measured in

the internal counter. A layer of thin conducting material is then placed

over the source, and the change in the count rate recorded. An area of a UDM-7, previously cut to fit the large-area counter, is measured in the

internal counter with the conducting layer over it. From this information, the emission rate of the reference piece of the UDM-7 can be determined. Any other UDM-7 can then be compared with this reference source

using the external counter.

Experiments With Resonance Ionization Mass Spectrometry (RIMS)

(J. M. R. Hutchinson & K. G. W. Inn)

Last year, NBS embarked on a DoE-supported program to assist in the

development of the RIMS technology with the ultimate goal of providing

suitable standards which will help to elucidate its role in research and,

particul arly, industrial applications. There are two components to the

effort, (i) use of the Sputter Initiated Resonance Ionization Spectrometer

( SIR IS) instrument to improve the SIRIS response, initially to uranium,

and to improve the isotope dilution technique, and (ii) production of

isotopic ratio standards, initially 10 Be/ 9 Be. With regard to this latter

effort, plans are under way to mount a seven laboratory collaboration

including the NBS Mass Spectrometry Group.

With regard to the first, two more working visits were made to Atom

Sciences in Oak Ridge, the developer of this revol ut i onary instrument used

in ultrasensitive analysis. Sources were prepared at NBS to test, and

help improve, a number of characteri sties of this instrument. Overall,

the conclusions reached from these visits were as follows:

Visit #1

1. The attachment of oxygen to uranium presents a major problem in

sensitivity for that element. The solution of this problem is of

major importance to this program.

2. At this time, the most promising method for calibrating the

system is by means of isotope dilution. The relationship of the

SIRIS response to a standard of one material and an unknown of

another is not clear for several reasons which include different

neutrals-to-argon-ion production, different angular and energy

distribution of neutrals, different amounts of quenching due to

oxygenation of the surface, physical differences in the surface,

chemical and physical effects of constituents in the sample other

than the one of interest, and reproduci bi 1 i ty of the current

density and indeed of the system from sample-to-sample.

193
Division 536, Technical Activities (cont'd.)

3. The homogeneity of the samples at the microscopic level appears

to be satisfactory for the sample that was investigated. This

implies that the graphite was adequately mixed with the sample.

4. Results of the source conductivity tests were inconclusive but

there was an indication that the signal was reduced by at least

a factor of two for nonconducting sources containing only KBr as

a binder relative to conducting sources containing graphite.

5. Comparison of SIRIS responses for vanadium concentrated in the

various soils and sediments gave generally expected results.

However, before a meaningful i nterpretation can be obtained, the

factors listed in item 2 (above) would have to be quantified.

6. The data support the picture that neutral uranium atoms are emitted copiously from metallic uranium, only uranium ions or ionic forms of uranium oxide are emitted from surfaces which are oxidized (such as the natural materials), yet vanadium neutrals

are emitted in large amounts from natural materials (which presumably contain vanadium oxide). Therefore, to obtain a significant SIRIS uranium signal from a natural material, ionic uranium

must be reduced either within the source or in an intense plasma

created during the sputtering process. It appears to be not

necessary to make this heroic effort for vanadium.

Visit #11

7. There is a large, unexplained improvement (factor of 5 to 26) in

the uranium response of the spiked, unfired graphite sample over

all the other samples. This difference is seen even over the

unfired spiked soi 1

.

8. Examination of the results of the spiked graphite and soil which

contain 235 U and 238 U in the same chemical form, shows that

instrumental uncertainties are in the few percent range at most.

9. No great effect was observed in the ratios of the responses due

to firing of the samples. By and large, firing seems to reduce

the response for a given isotope by at the most 30 percent.

10.

Overall errors in the observed isotopic ratios due to isotope

dilution are only on the order of a factor of two or less,

including machine-, chemical-, and physical -based uncertainties.

Further investigations could very well lead to methods for

improving this situation considerably. For example, etching the

phosphate ore samples with the d.c. beam for longer period to be sure that the insides of the particulates are being sampled may

improve the response.

194
Division 536, Technical Activities (cont'd.)

Progress With Radon-in-Water and Radon Flux Standards

(J. M. R. Hutchinson and R. Coll§)

The Environmental Protection Agency (EPA) has supported efforts

related to the monitoring of radon in the environment. This program

represents a collaboration between the Office of Radiation Measurement,

CRR and the Radioactivity Group.

The radon-in-water standard is concerned with the correct measurement

of gaseous, potentially harmful radon in drinking water. During this

year, an instrument which delivered an accurately known activity of radon

in an accurately known volume of water was completed and sent to the EPA

laboratory at Las Vegas where it is in daily use.

A second radon standard, which is under development, aims to provide

an accurately calibrated radon flux from a surface large enough to calibrate commerical radon-monitoring equipment. The program for the development of this standard has proceeded in four stages (i) development of a gas-handling system which can be used to sample the radon flux from the

standard and enable the sample to be measured in the NBS pulse-ionization

chamber; (ii) proving the principle of the standard; (iii) construction of

the standard, including design of a configuration for the measurement of

the flux; and (iv) measurement of the flux. The first three stages are essentially complete and the fourth stage is beginning.

Measurements with High-Efficiency Nal(Tl) Detection Systems (C. Ballaux)

A guest worker from the Studiecentrum voor Kernenergie, Mol, Belgium

used one of the group's high-efficiency scintillation-detector systems to

check a 133 Ba basic activity calibration previously established with a pressurized proportional counter anticoincidence system, and another to

check previous direct gamma-ray-emi ssi on-rate measurements of 109 Cd.

The analysis of measurements of 133 Ba sources between two 8" by 4"

Na I( T1 ) well-crystals uses a calculated efficiency based on a measured

efficiency vs_ energy relation and a known decay scheme. The calculated

probability of not detecting any radiation from a complex decay (here

about 3 percent) is not sensitive to branchings or internal conversion

coefficients if the detector efficiency is high for all radiations. The

133 Ba result agreed with the previous value to about 0.3 percent.

The measurement of the 88-keV gamma ray of 109 Cd with smal 1 -di ameterwell 2" by 2" Nal(Tl) detectors involves several small corrections to the

calculated total efficiency. A re-evaluation of these corrections led to

an emission-rate value differing from the previous measurement by about

0.8 percent.

195
Division 536, Technical Activities (cont'd.)

Gas Counting (F. J. Schima and M. P. Unterweger)

This year two samples of hydrogen-tritium (HT) gas have been calibrated in the length-compensated gas-proportional counting system. The

first sample, from W. R. Miller of the Gas and Particulate Science

Division (NBS), contained enough gas for us to accurately measure a known

gram-mole amount. A specific activity of 1.075 x 10 6 Bq/liter was determined with an overall uncertainty of 3.1 percent. The random error for

five measurements was 0.14 percent. The second sample, from LMRI, was counted totally, as the quantity of HT gas was too small for an accurate

gram-mole determination. The result for LMRI ampoule #1 was 1.086 x 104 Bq with an overall uncertainty of 3.4 percent and the random uncertainty

for six measurements was 0.14 percent.

In addition to these activity determinations, a detailed study of the

beta spectrum from the tritium decay is in progress. The ultimate goal of

this study is a comparison with theoretical spectra for the energy region

from 50 to 18400 eV to check if tritium beta decay is consistent with the

emission of a single neutrino of nearly zero mass.

Gamma-Ray Spectroscopy (F. J. Schima)

Successive-approximation analog-to-digital converter systems made by

EG&G Ortec, Inc. have taken over most of the pulse-height data-acqui sition

duties in the Radioactivity Group. Three of these units, known as ADCAM's, are now used to acquire data from the five main semiconductor

detectors. An unsuccessful effort was made to use an ADCAM in a multiplexed mode. Most of the software that had been used to process data

obtained with the previous PACE system has been successfully transcribed

to operate the ADCAMs and process data. Additionally, an automatic peak

fitting program has been developed which samples the channel contents

above and below the peak distribution for a background estimate.

Procedures are under development to incorporate measurement results automatically into our existing efficiency-function data base.

Computer System (M. P. Unterweger)

The Charles River Data System has had the number of user ports

increased by eight to a total of twenty ports. The system still supports

typically only five terminals which serve the staff computational and

data-reduction needs. However, the increase in user ports allows for the

direct service of all the Group's present data-acquisition systems such as those for the liquid-scintillation counters. Control and processing procedures for the latter have been implemented on the Charles River System.

In fact, all of the data acquisition programs supported by the Data

General Nova have been transferred to the Charles River System. The halflife data files, however, remain on the Nova.

196
Oivision 536, Technical Activities (cont'd.)

An 8-bit microcomputer obtained as surplus has been put into operation for handling data-based files and programs related to the SRM and

calibration services. These include mail lists, form letters, and shipping forms. A new IBM Quietwriter printer has been installed and used

with Wordstar and DBASE II programs.

Computer-Controlled Dispenser For Preparing Radioactive Sources

(L. L. Lucas)

~

As part of the "cross-check" program carried out by the Environmental

Protection Agency (EPA) for the Nuclear Regulatory Commission (NRC) under

an interagency agreement, identical samples of radioactive materials are supplied to participating commercial, educational, governmental, and other

laboratories for analysis as unknowns. The results, reported to EPA and

tabulated by them, serve as a "cross-check" of the accuracy and reproducibility of individual laboratory measurements. This helps to identify and

correct measurement problems and to improve measurement assurance.

One common type of radioactive material used in the program consists

of a piece of filter paper impregnated with one or more radionuclides.

These spiked filter-paper sources, which are produced in several sizes and

in quantities of up to several hundred at a time, are used to simulate

filter-paper sources from air samplers. Air samplers are extensively used

to monitor exhaust gases and the general environment for radioactive

particul ates.

The production of large quantities of identical spiked-f i lter-paper

sources requires accurate, repetitive dispensing of radioactive solution

in a careful ly-control led pattern and sequence -- an ideal task for a computer-control led dispenser. Linder contract to NRC, the Radioactivity

Group is producing such a dispenser. Several features of the device that

are considered essential for its intended use are:

(1) Modularity

High-quality, commerci al ly-avai 1 able components are used whenever

possible to make repair, replacement, and replication as simple as possible. The interfaces to the dispenser and positioner mechanisms are RS232C so that the operation can be controlled by virtually any computer at

any distance.

(2) Resistance to corrosion and contamination

All of the components in contact with the radioactive solution (tubing, valve, and syringe) can be removed without contaminating the rest of

the system. The dispenser and positioner mechanisms can be isolated from

the work area to avoid corrosion (the radioactive solution is often

strongly acidic and emits acid fumes as it dries).

197
Division 536, Technical Activities (cont'd.)

(3) Simple control

The dispensing and positioning mechanisms are controlled by simple

sequences of ASCII characters. Each mechanism provides verification that

a command has been received and carried out. This greatly simplifies the

computer programming.

The unit is expected to be operational in early FY 1986 and to be

producing spiked filter-paper sources a few months thereafter.

SRM's Delivered (B. M. Coursey)

During the year August 1984 through July 1985 nineteen radionuclides

were distributed as radioactivity Standard Reference Materials. These

included x- and gamma-ray SRM's for photon detector calibrations: 55 Fe,

57 Co and long lived mixed ( 125 Sb, 154 Eu, 155 Eu) solutions. Four hiqh-Z

nuclides were distributed for use in traceability tests: 208 Po, 229 Th,

243 Cm and 226 Ra. The NBS high level 3 H-water standard (SRM 4927C) was

also reissued. The radiopharmaceutical SRM program resulted in the

distribution of the following ten short half-life radionuclides: m In,

99mTc, 32 P, 203 Pb, 131 I, "Mo, 67 Ga, 133 Xe, 201 T1, and 51 Cr.

FDA 99mTc Clinical Measurements Check (B. M. Coursey, J. M. Calhoun,

D. Golas)

The USFDA enlisted the support of NBS in a nuclear -medicine qualityassurance program with a commerical supplier of 99mTc radiopharmaceuti

cals. SYNCOR, which operates 36 regional distribution facilities, agreed

to furnish calibrated syringes of 99mTc to their customers and to

collect their results and provide them to the College of American

Pathologists (CAP) for evaluation. NBS provided calibration services to

the SYNCOR corporate laboratory and measured standard syringes submitted

by nine of the regional facilities.

Liquid-scintillation Counting (B. M. Coursey)

This was the first year of a 5-year cooperative program with the

Junta de Energi a Nuclear on the development of liquid-scintillation techniques in radionuclide metrology. The first year objective was the standardization of pure beta-particle emitters. Standards were developed for

6

3

N i , 241 Pu, 14 C, and 90 Y, which cover a beta-particle energy range from

20.8 to 2283 keV. The overall uncertainties in these standards are of the

order of 1 percent.

Computation of counting efficiencies were continued on the JEN UNIVAC

and at the NBS UNIVAC on the three programs: EFFY (pure beta emitters),

VIAS (electron-capture emitters) and GAMMAS (a Monte Carlo code for photon

interactions). In addition, measurements were made to compare with computer calculations for three simple EC radionuclides: 55 Fe, 54 Mn and 51 Cr

and one internal transition nuclide 99mTc.

198
Division 536, Technical Activities (cont'd.)

Liquid scintillation techniques were developed for the measurement of

low-level tritium in water samples. These samples were prepared by quantitative combustion of tritiated methane and tritium in hydrogen gas. The

liquid scintillation results were used to assign activity concentration

values to the original gaseous samples.

Container Dependence In Dose-Calibrator Measurements (J. M. Calhoun,

D. Go las)

The commerical dose calibrators used for checking the activity of

radiopharmaceuticals in syringes before injection are calibrated with

solutions in 5-mL NBS ampoules. Commercial reference materials are usually supplied cast in epoxy in plastic bottles. However, sample

position, sample volume, and container type may be significant in dose

calibrator measurements. In order to check for possible errors of this

type, comparative measurements of two radionuclides in different volumes

in three containers were made.

A joint project between NBS and duPont/NEN, a producer of radiopharmaceuticals and reference sources, compared the indicated activity of 57 Co

samples in NBS 5-mL ampoules, syringes, and NEN Vial "E" epoxy- and

solution-filled bottles, and 99mTc solutions in NBS 5-mL ampoules, NEN

Vial "E" bottles, elution vials, and syringes. The measurements were made

iq typical dose calibrators obtained from two different manufacturers,

Capintec and Radcal. The main objective of the project was to examine the use of the NEN Vial "E" as a suitable reference source for dose calibrators, and assay 99mTc in elution vials and syringes.

Measurements were performed at NBS and at duPont/NEN. Several conclusions could be drawn from the observations. All the calibrators gave

results within two percent of the NBS activity in all cases where measurements were made in NBS ampoules. Sources in epoxy gave a higher response

than NBS ampoules because of the lower density and other geometry considerations. Vial "E" bottles never showed greater than four percent difference from the NBS value in either solution or epoxy. All syringes showed

decreasing response with increasing volume of solution or epoxy, with

57 Co. The brand of syringe used had little significance on the results.

Each manuf acturer ' s calibrator showed varying deviations from the NBS

value in different geometries due to differences inherent in the design of

each chamber or sample holder, or where the NBS ampoule was positioned

when the instrument was originally calibrated. The Radcal calibrator

showed the largest deviations with syringes suspended from the sample

holder. The Capintec calibrator showed the largest deviations with

elution vials at low volumes.

The exercise illustrated that regardless of the brand of dose calibrator used, a calibration factor for each geometry should be determined

to ensure the highest accuracy. The data show that as much as a nine

199
Division 536, Technical Activities (cont'd.)

percent difference from the correct activity can be recorded in certain

situations, even when the ampoule reference source is giving the correct

answer. Variations are also dependent on the radionuclide. These results

will be published.

Handbook of Radioactivity Measurements Procedures Published (W. B. Mann)

The National Council on Radiation Protection and Measurements

recently published a revised edition of NCRP Report No. 58, A Handbook of

Radioactivity Measurements Procedures , edited by Wilfrid B. Mann, former

NBS section chief and group leader for Radioactivity, and present guest

worker. The first edition of this work, published in 1978, has been

accepted as a definitive reference in the metrology of radionuclides.

The 1985 edition features new material on liquid-scintillation

counting, including techniques under development at NBS in cooperation

with the Junta de Energia Nuclear of Spain, and an added section on uncertainty statements and traceability methods for radioactivity calibrations. An appendix of over 150 pages lists pertinent nuclear decay

data for significant radionuclides.

VI . X-ray Physics Group

High Intensity Gamma-Ray Dosimetry (J. C. Humphreys & W. L. McLaughlin)

The amount of high-dose calibration and test service work performed

for industrial radiation processing customers has continued to expand,

following the trend of recent years. The total number of calibrations

performed was approximately 100 with a subsequent fee income of about

S 100k . This is an increase in fee income of about 40 percent over last

year. The calibration technician added to the staff last year has enabled

the staff to handle this increased calibration service business by greatly

improving the efficiency of operation. That has subsequently reduced

significantly our turnaround time for these calibrations. Other improvements to the calibration service include the automation of data acquisition from the spectrophotometer dosimeter analysis equipment. Microcomputers and other dedicated data acquisition equipment have been acquired

and will enable the staff to complete the automation of all data handling

and processing in the near future, including final calibration report

generation. In addition, the new high dose-rate Gammacell 60 Co irradiator

acquired last year is being fitted with a gas cooling system for the irradiation chamber to allow irradiation of temperature sensitive dosimeters

and samples. This will enable the staff to perform a high-accuracy calibration of the dose rate and thus allow this irradiator to be put on line

in the dosimeter calibration service. Use of the Gammacell should

increase the throughput for the service by at least a factor of two.

200
Division 536, Technical Activities (cont'd.)

Another improvement to the calibration service was the addition of a humidifier to the air conditioning system of the laboratory used for the

handling and irradiation of all dosimeters. This will provide the proper

environmental conditioning for the humidity-sensitive dosimeters during

the winter months and avoid any interruption in performing calibration

services. Efforts continue on developing criteria for the acceptable

performance of secondary dosimetry calibration 1 aboratori es

.

Standards committee work continues to play an important role in the

development of radiation processing technology. NBS staff have been the

principal authors of several new draft standards within ASTM subcommittee

E107.07. A number of these standards deal with food irradiation dosimetry. Since the food irradiation industry appears to be on the potential

threshold of rapid (perhaps explosive) expansion, it is very important

that adequate dosimetery techniques and methods be available to this

industry at this time. Participation continues in the Association for

Advancement of Medical Instrumentation dosimetry task group including the

round-robin dosimetry intercompari son of 60 Co facilities at NBS and seven

industrial medical product sterilization plants in Canada and the U.S.

Work has been initiated in that task group to develop new electron dosimetry standards since there is increasing interest within the industry in

utilizing the new generation hiigh-power accelerators now available for

radiation processing.

Development of the prototype liquid-core optical waveguide dosimeter

for personnel use continues. Some of the new results include the measurement of the temperature dependence of the absorbed dose response, improved

reproduci bi 1 i ty in the fabrication of the wave guide, improved techniques

in reproducible optical alignment for spectrophotometric analysis and

measurement of dosimetric sensitivity in both gamma and neutron fields.

Another important development was the use of the optical waveguide as a real-time dosimeter. This application of the dosimeter promises to have

exciting potential uses in such areas as in situ medical diagnostics. The

basic design uses a light source such as a laser or light emitting diode

to illuminate one end of the coiled wave guide and a photodiode detector

at the other end. Measurements have been made on the reproducibl ity of

the dose response on the dose rate dependence, on the effect of optical

path length, on the effect of the coil radius, on the effect of the illuminating light wavelength, and on the i ntercompari son with spectrophotometric type of analysis.

International standards activities in high-dose dosimetry included

several important functions. The Report to the International Commision on Radiation Measurement and Units entitled "Dosimetry for Radiation

Processing" from the Committee chaired by W. L. McLaughlin was formally

submitted to the Commission in 1985. A new Advisory Group on High-Dose

Measurements of Electron Beams for Radiation Processing was formed in 1985

by International Atomic Energy Agency, with McLaughlin as a charter

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Division 536, Technical Activities (cont'd.)

member. McLaughlin and Humphreys participated in a three-nation (US, UK

and Denmark) absorbed dose intercompari son of graphite calorimeters for

high-dose standardization. Arne Miller from the Ri so/National

Laboratory of Denmark spent five weeks as a guest worker at NBS in late

1984 assisting in the development of these calorimeters as new national

primary standards of absorbed dose at high doses. Initial plans were also

made with the Gesellschaft fUr Strahlen-und Umweltforschung of the Federal

Republic of Germany for them to be included in future standardization

intercompari sons with NBS.

Dental Fluoroscopy and Tomography (J. W. Motz & J. H. Sparrow)

In collaboration with the National Institute of Dental Research, the

X-ray Physics Group is developing a dental tomographic system which will

have the capability of producing dental images at different depths in any

given tooth. The system requires the development of a special x-ray tube,

intra-oral image detector, and image processing system which can provide

and process several dental images in less than a second. Each of these

components has been designed and is curently in process of construction,

with the expectation that tomographic images will be produced in FY 86.

At the request of the Army Institute of Dental Research, the X-ray

Physics Group has developed a hand-held dental fluoroscopic system which

has the potential for order of magnitude lower x-ray exposure than that

required with dental film and which has the capability of image storage

and retrieval on a floppy disc. This system is presently under test and

will require further development for the specific needs of standardization

in army field operations.

Performance Evaluation of DOD High Energy Radiological Inspection Systems

(D. Polansky)

At the request of the Navy Department, this program carries out the

fol lowing tasks:

1. Establish a measurement procedure such that facilities performing

high energy radiological inspection on missiles can calibrate the x-ray

output of the linear accelerators they are using. Until such time as the

facilities have on hand the calibrated equipment and trained personnel to

perform the measurements, NBS staff members will continue to provide these

services every 12 to 18 months.

2. Perform an on-site audit of the radiological image quality

achieved at the various DOD facilities and at the various DOD product

manuf acturer; participate in the new design of a test specimen used to

evaluate both image quality and system performance for CT systems used in

the radiological inspection of missile propulsion units and gas

generators.

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Division 536, Technical Activities (cont'd.)

3. Assist in the integration of old and new radiological inspection

methods (film, real time and tomography) to assure that there is a consistency in the quality of inspection so that data from different inspections

can be correlated.

Nondestructive Testing of Very Thick Walled Castings (R. C. Placious)

At the request of Sandia Laboratories, NBS was asked to survey the

present state of the art in nondestructive inspection of very thick-walled

(12"-15") ferrous metal casks. This is a team effort in which the X-Ray

Physics Group participates in the radiological aspects of the program.

The primary material of interest here is a relatively recent development so that the technical base for fabrication and inspection is still

maturing. To the extent possible, the quality of inspection presently

achievable with similar, but not identical, materials will be evaluated.

We are also asked to evaluate the quality of inspection that may be

achievable as a result of newer, emerging radiological methods and to

recommend the specific NDT technologies that should be pursued for

inspecting huge monolithic steel/cast iron castings.

Standard Visual Test Patterns for Radiographic Interpreters

(R. C. Placious)

Field testing of the first set of slit images indicated that skilled

readers could score better than 90 percent without adhering to the test

protocol. We are modifying some of the slit patterns to increase the

difficulty of detecting some of the patterns. The new test set will be

distributed to several laboratories for evaluation.

Radiographic Image Quality Standards (R. C. Placious)

Present work on a method of image quality evaluation is directed at

the very high (5-15 MeV) and the very low (10-50 keV) x-ray energies.

Consideration is being given to a redesign of image quality indicators

especially at the high x-ray energies. Cooperative work with industry

members of the nondestructive testing committee in ASTM is continuing on this task.

Accelerator Radiation Sources (C. E. Dick)

The X-ray Physics Group operates, maintains and uses three electron

accelerators for the production of electron and photon beams. These

sources are used for a variety of programs related to dosimetry, pulsed

radiolysis, medical and industrial radiography, and basic measurements.

In the past year, utilization of these sources has increased with the

continuation of ongoing programs and the utilization of these sources by

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Division 536, Technical Activities (cont'd.)

various groups outside of NBS. In the following, the operating parameters

and current status of each of these accelerators is described along with a brief description of the research activities currently under way.

(A) 500-keV Constant Potential Accelerator (C. E. Dick)

The 500-keV cascaded rectifier accelerator has been in use for over

30 years as a low energy electron and photon source. This machine

continues to be one of the most reliable pieces of apparatus in the group.

The electron energy is continuously variable from 0.01- to 0.5-MeV with

beam currents from 10“ 9 - to 10_4 -Ampere. The accelerator is equipped with

a scattering chamber for differential angular measurements from 0- to 175-

degrees, or the electron beam can be deflected to provide a horizontal

beam for other experiments. Currently, the accelerator is being utilized

for the following experiments:

• The production of standard electron beams for the calibration

of instruments used for beta-ray dosimetry. Work is currently

under way to determine the energy spectra and fluence of these

beams which are brought out of the high-vacuum of the accelerator

through a thin window into the air.

• A collaborative effort is underway to investigate possible coherence effects in the production of Cerenkov radiation. The optical spectra

of the radiation emitted by this process is currently being investigated

by a group from Howard University.

• The electron beam from this accelerator has been used to produce

monoenergetic-photon beams in the region from 10- to 70- keV.

These beams will be used by a guest worker from France to investigate the properties of halogenated and rare-earth compounds used

as contrast media in medical radiography.

(B) 1 . 5 MeV Dynami tron (C. E. Dick)

The 1.5 MeV dynamitron is an extremely stable source of electrons in

the energy range from 0.2 to 1.25-MeV. The vertical beam from this accelerator is deflected horizontally by a magnetic field and can be directed

into either of two scattering chambers. Beam currents range from 10-9 - to

10~ 3 -Ampere. Currently this source is being utilized in the following

efforts

.

• Measurement of photon spectra produced by variations in the

electron energy, target material, observation angle, and beam

filtration. These measurements are designed to produce quasi

monoenergetic photon beams in the region from 0.1- to 1.0- MeV for

digital subtraction imaging and industrial radiography studies.

204
Division 536, Technical Activities (cont'd.)

• An experimental setup has been constructed to utilize high intensity monoenergetic photon beams in the sub 100-keV regime to

investigate the effects of electron binding on the Compton

scattering process for photons.

(C) Electron Van de Graaff (C. E. Dick)

The 4-MeV Van de Graaff electron accelerator has been in use for over

15 years as a source of high energy electrons and photons for Division

programs in atomic and molecular physics, nuclear physics, dosimetry, and

the production of standard radiation fields for instrument calibration.

This accelerator has been extensively modified to enable the production of

pulsed electron bunches to be used in experiments in pulsed radiolysis and

chemical kinetics. At present, the accelerator is capable of producing

pulsed electron beams with 6 fixed pulse widths between approximately 5 nanoseconds and 5 microseconds with beam currents of up to 0.5 amperes in

the pulse. In the present configuration, these beams are available at

energies from 1.2- to 2.75- MeV at an experimental location directly below

the accelerator structure. Work is under way to provide the capability to

deflect these beams into a larger experimental area without significant

loss in beam quality, and to extend the maximum energy above 3 MeV. These

additional capabilities will require extensive modifications to the electron gun assembly and beam-handling optics. The accelerator is also

capable of producing dc beams from 10~ 9 - to 10~4 -Amperes at five horizontal locations. Present uses include:

• The generation of electron beams of known energy and fluence for

the calibration of instruments used in beta-ray dosimetry. These

beams have been used by groups from Los Alamos and Idaho Falls for

the calibration and characterization of instruments under development.

• An effort to investigate the presence of coherence effects in the

processes of transition radiation and the Smith-Purcell effect as electrons interact with periodic structures. This program is

being carried out with a group from the Lawrence Livermore

National Laboratory.

• Measurements have been made on the pulsed electron beam at the

straight-through beam position to determine the suitability of the

beam for pulsed radiolysis. These measurements indicate that the

beam in this position is quite usable for these measurements. In addition, preliminary designs for a non-di spersi ve magnetic

deflection and focusing system have been considered in order to

provide the same quality beam at two horizontal beam locations.

205
Division 536, Technical Activities (cont'd.)

Digital Energy Subtraction Imaging For Biomaterials (C. E. Dick)

A program has been initiated to investigate the application of

digital energy subtraction to the imaging of biomaterials used in medical

applications. In this technique, the differential absorption of different

energy photons is utilized to provide a difference signal between the

structure of interest and the surrounding medium. Previously, we have

developed the basic methodology to produce quasi -monoenergetic photon

beams by filtration of spectra produced by conventional x-ray machines.

Presently, experiments are under way to provide subtraction of various

structures approximating those found in medical radiology. In addition, a computer algorithm has been developed to predict the shape of these

filtered spectra from a set of baseline spectra. This computer algorithm

generates a reasonable approximation of the effects of various filters

without the necessity to make tedious measurements for all materials.

In order to examine the energy subtraction technique, we have assembled a real time imaging system with image processing capabilities. This

system consists of a 23-cm diameter image intensifier tube whose output is

viewed by a television camera. The analog output of the camera is digitized and stored by a computer-based image processing system. In the last

few months, extensive renovations and testing of this system has been

under way and it is now ready for the recording of images. In addition,

the procurement of a medical phantom designed for the evaluation of images

generated in Digital Subtraction Angiography (DSA) has been initiated.

This phantom will allow the investigation of geometries and materials

encountered in medical radiography.

VII . Electron and Photon Dosimetry Group

Use of ionizing radiation is becoming ever more widespread in modern

society. The exposure of humans can be purposive (medical) or incidental

(occupational), but both require close control to ensure that the radiation is efficacious in the one case, and harmless in the other. Such

control can only be achieved with reliable measurement. With the

increased use and the improved knowledge of radiation effects, the need

for more accurate measurement is constantly increasing. The measurement

of ionizing radiation for the purpose of controlling a radiation effect

falls in the field of radiation dosimetry. The Electron and Photon

Dosimetry Group has the responsibi 1 ity for providing an up-to-date basis

for reliable measurement of ionizing radiation, principally in medicine

and radiation protection. This program involves: (1) establishment and

maintenance of the national primary dosimetry standards; (2) dissemination

of the units established by those standards by means of calibration

services and measurement quality assurance programs; (3) research and

development of measurement technology as necessary for any part of the

program; and (4) participation in the relevant national and international

activities of the community of radiation users.

206
Division 536, Technical Activities (cont'd.)

X-ray and y-ray Calibration and Measurement Assurance Services

(J. T. Weaver & P. J. Lamperti)

Calibration services for x-ray and Y-ray measuring instruments have

continued to increase in efficiency, aided considerably by the addition

of a junior technician in May 1985. The reimbursable income for the 350

tests performed was $140,000. Principal users were medical institutions

and nuclear power establishments.

The operating system for the dedicated DEC 1123 minicomputer was updated from the RT11 version 4 to version 5.1, to permit transfer of the

files over the NBS Net to the new NBS Cyber 855 computer. The main calibration program, written over a period of ten years in Fortran 66 (UNIVAC

Fortran V), was converted to Fortran 77 for the UNIVAC 1100/82 computer,

and then adapted for the Cyber 855.

Measurement assurance tests have been carried out with the five AAPM

therapy-level accredited calibration laboratories of the AAPM, and to five

protection-level 1 aboratories. As usual the test equipment was shipped

around to all the laboratories before return to NBS, using the check

methods devised for the particular equipment being used. Traceability to

NBS is maintained by the measurement assurance test, without recal i bration

of the local standard chamber, unless the test shows it to be necessary.

The Navy thermoluminescence dosimetry (TLD) measurement assurance

program continues. The program is sponsored by the Naval Electronics

System Command, and involves preparation by NBS of boxes of 15 TL dosimeters, 12 of which have been given known exposures to 137 Cs gamma rays.

The boxes are dispatched to designated Naval units for readout, the

results of which are returned to NBS for comparison with the NBS exposures. TL readers that indicate exposures differing from the NBS exposure

by more than ±13 percent are repaired and recal i brated . About 275 such

boxes, containing 3300 exposed dosimeters, were dispatched during FY85.

Complete documentation of NBS photon dosimetry standards and calibration techniques was prepared by T.P. Loftus, under a 6-months contract.

Loftus, who retired in June 1984, had more than 30 years' experience with

NBS calibration procedures, and was in a unique position to carry out this

task. The material will be edited for publication as an NBS Internal

Report.

High Energy Electron and Photon Measurement Assurance Services

(C. G. Soares)

There were four mailings of Fricke dosimeters in FY85, involving 62

sets of participants, engaged primarily in radiation therapy. Two batches

of dosimeters were prepared. In principle, each dosimeter can be used as many times as it takes to accumulate 200 to 300 Gy. In order to conserve

207
Division 536, Technical Activities (cont'd.)

time, and thus cost to the participants, the tests are administered simultaneously to as many participants as the batch size permits. In order to

handle the increase in volume that the service has experienced in the last

few years, 60 new cells have been ordered, which will allow an increase in

the number of cells per mailing, and possibly a decrease in the number of

mailings. We are investigating a change to a system using inexpensive

sealed vials instead of spectrophotometer cells. This should reduce the

variability of response changes with time, resulting in improved accuracy

and sensitivity. It is planned to augment the chemical dosimetry service

with a TLD service, if technical problems connected with the required

extensive automation can be solved.

Standard Monoenerget ic Electron Beams (C. G. Soares)

Work continued on the development and characterization of monoenergetic electron beams for the calibration of instruments used primarily in

radiation protection. Spectral measurements of the electron beams were extended to 2.5 MeV with the 6.3-mm thick lithium-drifted silicon spectrometer. Efforts are being made to improve reproduci bi 1 i ty in monitor

calibrations and delivered doses. An additional monitor has been added to

the electron Van de Graaff beam line, as well as a beam collimator to

better specify the beam direction. During FY86 these beams will be used

to make further measurements of electron response functions of betasensitive radiation protection instruments.

Extension of Instrument Calibration Capability to 6.5-MeV Photons

(C. G. Soares)

An approximately 6.5-MeV photon beam is obtained from the

19 F(p,ay) 16 0 reaction using protons produced in the positive-ion Van de

Graaff generator using a thick CaF

2 target. Pulse-height distributions

were measured with an intrinsic Ge detector and a Nal(Tl) detector whose

response functions are known. Progress was slow during FY85 due to difficulties with the accelerator and the spectral unfolding procedures. The

energy of the incident proton beam was increased from 2 to 2.7 MeV in

order to increase the high-energy photon output of the reaction, and

pulse-height spectra were remeasured at this higher proton energy. When

the accelerator is again available, the in-phantom paral lei -pi ate ionization chamber will be used to attempt more accurate dosimetry than was possible at the lower photon output with thermoluminescent dosimeters. It is expected that the salient features of the results will be incorporated

in an international standard being developed under the auspices of ISO/TC

85/SC 2/WG 2.

208
Division 536, Technical Activities (cont'd.)

Beta-particle Source Calibration and Associated Measurement Assurance

Services' (J. S. Pruitt)

The NBS extrapolation chamber has been used with the standard betaparticle sources (L47 Pm, 204 T1, and 90 Sr+90 Y) for a variety of measurements during FY85. These include: comparison of depth-dose curves for

three 90 Sr+90 Y sources with different encapsulations; calibration of three

other 90 Sr+ 90 Y sources as a function of source distance; comparison of the

noise characteri sties of two low-noise cables; measurement of the correction factor for attenuation in the chamber volume; confirmation of the

correction factor for ion recombination and diffusion; and calibration of

beam monitors in two accelerators that generate approximately monoenergetic electron beams with energies between 0.1 MeV and 2.5 MeV. The lastmentioned study produced some unwanted background current in the extrapolation chamber, so another chamber was purchased, and one is now reserved

for low-intensity measurements, and the other for high-intensity

measurements

.

An accurate digital voltmeter and a calibrated capacitor were transported to the Idaho National Engineering Laboratory to calibrate the electrometer used there for beta-particle measurements. The electrometer was then used to calibrate their 204 T1 and 147 Pm sources, thus effectively

providing an NBS calibration without transporting their sources. These

calibrations provided a good check on previous measurements of the effect

of decreased atmospheric pressure on beta-particle source calibrations.

The plane-parallel ionization chamber previously obtained and calibrated for use as a transfer instrument was sent to Argonne National

Laboratory, Idaho Falls Laboratory (DoE), and Battel le Pacific Northwest

Laboratory. At each of the institutions the chamber was calibrated with

beta-particle sources that are essentially the same as the NBS sources,

and the NBS calibrations were repeated after the chamber was returned.

Some of the results are very close, and some less close, but due to variations in the measurement conditions, the interpretation of the results is

still under consideration at the time of writing.

Absorbed Dose Calorimetry (S. R. Domen)

The graphite-water calorimeter has been brought into operation.

Absorbed-dose measurements are made in a small mass of graphite immersed

in water. Adding graphite slabs will allow extrapolation to zero graphite

thickness, giving water absorbed dose while circumventing the problem of

the water heat defect. The same graphite slabs, without the water, will

convert this instrument to an all-graphite calorimeter, thus allowing

comparison with previous NBS measurements. Comparison of the graphitewater calorimeter, the polystrene-water calorimeter, and the graphite

calorimeters will provide a reliable NBS absorbed dose standard.

Preliminary measurements are in agreement with earlier results, indicating

an exothermic effect of about 3 to 4 percent in water that is not ultraclean.

209
SPONSORED WORKSHOPS, CONFERENCES, AND SYMPOSIA

Division 536, Ionizing Radiation

International Conference on "Mechanisms of DNA Damage and Repair.

Implications for Carcinogenesis and Risk Assessment". Chairman: M. G.

Simic, Co-chairmen: L. Grossman, A. D. Upton. NBS, June 2-7, 1985.

J. M. Calhoun served as Conductor of the Engineering and Chemistry Forum

of the Woman-Owned Small Business Symposium organized by the Department of

Commerce in May 1985.

J. M. R. Hutchinson, ICRM Conference on Low-Level Measurement Techniques,

Grenoble, France, June 3, 1985.

210
INVITED TALKS

Division 536, Ionizing Radiation

Behrens, J. W., "Applied Neutron Physics at the NBS," GWI, Uppsala,

Sweden, October 1984.

Behrens, J. W., "Recent Research in Experimental Neutron Physics,"

Harwell, England, November 1984.

Behrens, J. W., "Fission Cross Section Systematics in the MeV Range," at

ENEA, Comitato Nazionale Per l'Energia Nucleare, Bologna, Italy, December

1984.

Behrens, J. W., "Applied Neutron Physics at the NBS," FOA, Stockholm,

Sweden, December 1984.

Berger, M. J., "Electron Stopping Powers and Ranges," IAEA Advisory Group

Meeting on Nuclear and Atomic Data for Radiotherapy and Radiobiology,

Radiobiological Institute TNO, Rijswijk, The Netherlands, September 16-

20, 1985.

Calhoun, J. M., "Radioactivity Measurements at NBS", Womens Forum,

Standards Committee for Women, NBS, Gaithersburg, MD, March 20, 1985.

Carlson, A. D., "The Neutron Cross Section Standards Evaluations for

ENDF/B-VI," The International Atomic Energy Agency (IAEA) Advisory Group

Meeting on Nuclear Standard Reference Data, Geel, Belgium, November 12,

1984.

Carlson, A. D., "The ENDF/B-VI Evaluations of the Neutron Cross Section

Standards," Conf. on Nuclear Data for Basic and Applied Science, Santa Fe,

NM, May 17, 1985.

Carlson, A. D., "Nuclear Data Standards," American Nuclear Society,

Boston, MA, June 13, 1985.

Caswell, R. S., "Nuclear Data for Biomedical Applications", Conference on Nuclear Data for Basic and Applied Science, Santa Fe, NM, May 13-17,

1985.

Col 16, R., "Experts' Panel on Error Analysis", National Conference of

Standards Laboratories, 1984 Workshop and Symposium, NBS, October 1-4,

1984.

Coursey, B. M., "A 4tt 8(LS) Computational Method for Standardizing BetaEmitting Nuclides in Secondary Laboratories" , ICRM Working Group on Techniques for Radionuclide Metrology, Grenoble, France, June 4, 1985.

211
Division 536, Invited Talks (cont'd.)

Coyne, J. J., "Neutron Dosimetry with TE Ionization Chambers and

Proportional Counters," Rudjer Boskovic Institute, Zagreb, Yugoslavia,

April 9, 1985.

Coyne, J. J., "Neutron Kerma Factors and Their Importance for Neutron

Dosimetry," Bulgarian Academy of Science, Institute for Nuclear Science

and Energy, Sofia, Bulgaria, April 12, 1985.

Dizdaroglu, M., "Mechanisms of Biological Crosslinks in Model Systems",

National Research Council of Canada, Ottawa, Canada, September 1985.

Dizdaroglu, M., "Characterization of Free Radi cal -Induced Base Damage in

DNA", National Research Council of Canada, Ottawa, Canada, September

1985.

Dizdaroglu, M., "The Use of GC-MS for Characteri zation of RadiationInduced DNA Base Damage", Armed Forces Radiobiology Research Institute,

Bethesda, MD, April 1985.

Duvall, K. C., "The Development of a 6 to 7 MeV Photon Field for

Instrument Calibration," Application of Accelerators in Research and

Industry, Denton, TX, November 12-14, 1984.

Ehrlich, M., "NBS Facilities for the Study of Radiation Protection

Instruments", Personnel Radiation Dosimetry Symposium, Knoxville,

Tennessee, October 1984.

Eisenhower, E. H., "Radiation Measurement Support System", Region X Radiation Control Program Meeting, Seattle, WA, February 19, 1985.

Eisenhower, E. H., "The National Support System for Measurement Quality

Assurance", Topical Symposium on Quality Assurance in Ionizing Radiation

Measurement, Health Physics Society, Kennewick, WA, March 14, 1985.

Gilliam, D. M., "Cross Section Measurements in the 235 U Fission Spectrum

Neutron Field", Fifth ASTM-EURATOM Symposium on Reactor Dosimetry,

Geesthacht, West Germany, October 1984.

Hoppes, D. D., "Radioactivity Measurement Programs at NBS", Institute

d'Electrochimie et Radiochimie, Lausanne, Switzerland, June 1, 1985.

Hoppes, D. D., "Basic Radionuclide Measurements", ICRM Working Group on Techniques for Radionuclide Metrology, Grenoble, France, June 4, 1985.

Hoppes, D. D., "Photon Spectrometry from 5 to 100 keV", ICRM Gamma-RaySpectrometry Working Group, Grenoble, France, June 5, 1985.

212
Division 536, Invited Talks (cont'd.)

Hubbell, J. H., "Photon Interaction Data for Radiation Dosimetry. Current

Status and Prospects," Laboratorio di Metrologia dell Radiazioni Ionizanti, ENEA, Istituto Casaccia, Rome, Italy, October 23, 1984.

Hubbell, J. H., "Acceptance of 1985 Society of Nuclear Medicine

Paul C. Aebersold Award," 32nd Annual Meeting of the Society of Nuclear

Medicine, Houston, Texas, June 2, 1985.

Hutchinson, J. M. R., "Low-level Progress Report - NBS", ICRM Working

Group on Low-Level Measurement Techniques, Grenoble, France, June 3,

1985.

Hutchinson, J. M. R., "Sputter-Induced Resonance Ionization Spectrometry"

,

ICRM Working Group on Techniques for Radionuclide Metrology, Grenoble,

France, June 4, 1985.

Inn, K. G. W., "Reference Materials for Atom-Counting Cosmo-Geochemi stry

Measurements?", The 1984 International Chemical Congress of Pacific Basin

Societies, Honolulu, Hawaii, December 16-21, 1984.

Inn, K. G. W., "Chemical Challenges in the Certification of Environmental

level Radioactivity Standard Reference Materials", University of Arkansas,

Fayetteville, Arkansas, July 3, 1985.

McLaughlin, W. L., "Fiber Optics Dosimetry", Accelerator and Chemistry

Department, Ri so/Nat ional Laboratory, Roskilde, Denmark, October 4,

1984.

McLaughlin, W. L., "The Measurement of High Doses Near Metal and Ceramic

Interfaces", International Symposium on High Dose Dosimetry, International

Atomic Energy Agency, Vienna, Austria, October 9, 1984.

McLaughlin, W. L., "Response of Radiochromic Film Dosimeter to Gamma Rays

in Different Atmospheres", International Symposium on High Dose Dosimetry,

International Atomic Energy Agency, Vienna, Austria, October 11, 1984.

McLaughlin, W. L., "Energy Dependence of Radiochromic Response to X and

Gamma Rays", International Symposium on High Dose Dosimetry, International

Atomic Energy Agency, Vienna, Austria, October 12, 1984.

McLaughlin, W. L., "Standardization of High Dose Measurement of Electron

and Gamma-Ray Absorbed Dose and Dose Rates", International Symposium on High-Dose Dosimetry, International Atomic Energy Agency, Vienna, Austria,

October 12, 1984.

213
Division 536, Invited Talks (cont'd.)

McLaughlin, W. L., "Food Irradiation Dosimetry by Optichromic Techniques",

5th International Meeting on Radiation Processing, San Diego, CA., October

24, 1984.

McLaughlin, W. L., "Response of Radiochromic Film Dosimetry to Gamma Rays

in Different Atmospheres", 5th International Meeting on Radiation

Processing, San Diego, CA., October 25, 1984.

McLaughlin, W. L., "Plastic Film Materials for Dosimetry of Very Large

Absorbed Doses", 5th International Meeting on Radiation Processing, San

Diego, CA., October 25, 1984.

McLaughlin, W. L., "Response of Radiation Monitoring Labels to Gamma Rays

and Electrons", 5th International Meeting on Radiation Processing, San

Diego, CA., October 25, 1984.

McLaughlin, W. L., "Dosimetry for Applied Radiation Technologies",

Radiological Sciences Dept., Battel le NW, Richland, WA., November 1, 1984.

McLaughlin, W. L., "Calorimeters as Electron-Beam High-Dose Primary

Standards", Accelerator Department Seminar, Ri so/National Laboratory,

Roskilde, Denmark, May 22, 1985.

McLaughlin, W. L., "Radiation Dosimetry with Radiochromic Dyes", NBS-Boris

Kidric Institute Seminar, Boris Kidric Inst, of Nuclear Science, Vinca,

Belgrade, Yugoslavia, June 11, 1985.

McLaughlin, W. L., "Validation Procedures and Dosimetry in Routine

Industrial Radiation Sterilization", U.S. Food and Drug Administration

Training Course, Ramada Inn, Culver City, CA., June 26, 1985.

McLaughlin, W. L. and Humphreys, J. C., "Industrial Radiation Technology",

FMC Corporation, Santa Clara, CA, September 26, 1985.

Radak, B. and McLaughlin, W. L., "Radiation Dosimetry with Radiochromic

Dyes", Seminar on Scientific Cooperation between NBS and IBK in the 1980-

1985 period, Boris Kidric Inst, of Nuclear Science, Belgrade, Yugoslavia,

June 10-11, 1985.

Seltzer, S. M., "Calculated Depth-Dose Distributions in Multi-layer Media

Irradiated by Electrons," Conference on Applications of Accelerators in

Research and Industry, Denton, Texas, November 12-14, 1985.

Schwartz, R. B., "Neutron Personnel Dosimetry Calibration", Personnel

Radiation Dosimetry Symposium, Knoxville, Tennessee, October 17, 1984.

Simic, M. C., "Fat Oxidation and Antioxidants", Nabisco Brands Lipid

Symposium, Nabisco, Rochelle Park, N.J., November 15-16, 1984.

214
Oivision 536, Invited Talks (cont'd.)

Simic, M. G., "What's New in DNA Damage", Association for Radiation

Research", U. Newcastle, England, December 18-21, 1984.

Simic, M. G., "Dosimetry of Dosage Received. Irradiated Foods: A New

Business", Food Processors Institute, San Francisco, CA, February 15,

1985.

Simic, M. G., "Antioxidants. Kinetics and Mechanisms", Lipid Oxidation

Symposium, Am. Chem. Soc., Miami Beach, FL., April 28 - May 3, 1985.

Simic, M. G. and Dizdaroglu, M., "Mechanisms of Free Radical Crosslinking

in Biological Model Systems", Radiation Research Soc., Los Angeles, CA.,

May 3-9, 1985.

Simic, M. G., "Free Radical Mechanisms of DNA Base Damage", First

Conference on Mechanisms of DNA Damage and Repair, NBS, Gaithersburg, MD,

June 2-7, 1985.

Simic, M. G., Dizdaroglu, M., and Karam, L., "Chemical Analysis of

Irradiated Foods", Am. Nuclear Soc., Boston, MA., June 10-15, 1985.

Simic, M. G. and AlShiekhly, M., "Superoxide Radical Generation in

Radiation-induced Autoxidation of Fatty Acids", 4th Int. Conf. on Superoxide and Superoxide Dismutase, Rome, Italy, September 1-6, 1985.

Soares, C. G., "Development of Monoenergetic Electron Beam Sources for

Radiation Instrument Calibration", 8th Conference on Application of

Accelerators in Research and Industry, Denton, Texas, November 13, 1984.

Soares, C. G., "Medical Applications of TLD", Health Physics Society

Saturday Symposium Series, NBS, Gaithersburg, MD, September 28, 1985.

Wasson, Oren A., "Progress in the Detection of Low-Energy Neutrons," The

Fourth International Symposium on Neutron-Induced Reactions, Smolenice,

Czechoslovakia, June 17-21, 1985.

Wasson, Oren A., "Neutron Measurements at NBS," Institute for Nuclear

Physics at Rez near Prague, Czechoslovakia, June 24, 1985.

215
PUBLICATIONS

Division 536, Ionizing Radiation

Behrens, J. W., Johnson, R. G., and Schrack, R. A., Neutron Resonance

Transmission Analysis of Reactor Fuel Samples, Nucl. Technology 67, 162-

168 (Oct. 1984). —

Behrens, J. W., Johnson, R. G., and Schrack, R. A., Neutron Resonance

Transmission Analysis of Reactor Fuel Samples, Nucl. Technology 67, 162-

168 (Oct. 1984).

Berger, M. J., Discussion of Electron Cross Sections for Transport

Calculations, Proc. Workshop on Electronic and Ionic Collision Cross

Sections, Argonne National Laboratory, December 6-8, 1983, ANL-84-28

(1984).

Berger, M. J., Andersen, H. H., Bichsel, H., Dennis, J. A., Inokuti, M.

,

Powers, D., Seltzer, S. M., and Turner, J. E., Stopping Powers and Ranges

of Electrons and Positrons, Report of the International Commission on Radiation Units and Measurements, ICRU Report 37 (October 1, 1984).

Carlson, A. D., Behrens, J. W., Johnson, R. G., and Cooper, G. E.,

Absolute Measurements of the 235 U(n,f) Cross Section for Neutron Energies

from 0.3 to 3 MeV, Proceedings of the International Atomic Energy Agency

(IAEA) Advisory Group Meeting on Nuclear Standard Reference Data, Nov. 12-

16, 1984, Geel, Belgium, IAEA-TECDOC-335, 163 (1985).

Carlson, A. D., Nuclear Data Standards, Transactions of the American

Nuclear Society _49, 205-206 (June 1985) .

Carlson, A. D., Poenitz, W. P., Hale, G. M., and Peelle, R. W., The

Neutron Cross Section Standards Evaluations for ENDF/B-VI, Proceedings of

the International Atomic Energy Agency (IAEA) Advisory Group Meeting on Nuclear Standard Reference Data, Nov. 12-16, 1984, Geel, Belgium, IAEATECDOC-335, 77, (1985).

Carlson, A. D., Standard Cross Section Data, Prog. Nucl. Energy JJ, No.

2, 79-127 (1984).

Caswell, R. S., and Coyne, J. J., Recent Improvements in Neutron Energy

Deposition Calculations, Proc. Fifth Symposium on Neutron Dosimetry,

Munich, West Germany, September 17-21, 1984, Commission of the European

Communities, EUR 9762 I, 255-262 (1985).

216
Division 536, Publications (cont'd.)

Caswell, R. S., Epp, E. R., McCarthy, W. A., Mettler, F. A., Jr., Thomas,

R. H., Wagner, H. N., Jr., Walker, J. T., and Wyckoff, H. 0., SI Units in

Radiation Protection and Measurements, National Council on Radiation

Protection and Measurements, Bethesda, MD, NCRP Report No. 82, 64 pp.,

(March 13, 1985)

.

Chrien, R. E., Kopecky, J., Liou, H. I., Wasson, 0. A., Garg, J. B., and

Dritsa, M., Distribution of Radiative Strength from Neutron Capture by

239 Pu, Nucl . Phys. A436 , 205-220 ( 1985).

Creagh, D. C. and Hubbell, J. H., Lessons from the I.U.Cr. X-Ray

Attenuation Project, Acta Crystallogr. A 40 , C- 17 5 (1984) (Abstract, 13th

Int. Congr., Int. Union of Crystal logr . , Hamburg, Germany)

.

Coursey, B. M., Book Review, Advances in Scintillation Counting, Int. J.

Appl . Radi at. Isot. 36, 331-332 (1985).

Coursey, B. M., Gibson, J. A. B., Heitzmann, M. W., and Leak, J. C.,

Standardization of Technetium-99 by Liquid-Scintillation Counting, Int. J. Appl. Radiat. Isot. 35_, 1103-1112 (1984).

De Leeuw-Gierts, G., De Leeuw, S. (SCK/CEN), Gilliam, D. M. (NBS),

Comparison of Theoretical and Experimental Neutron Spectra, 115 In(n,n')

and Fission Rates, in the Centre of Three Spherical Natural Uranium and

Iron Shell Configurations, Located at BR1, Proc. Fifth ASTM-EURAT0M

Symposium on Reactor Dosimetry, Geesthacht, Germany, Sept. 24-28, 1984

(1985)

.

Dias, M. S. (Sao Paul o-Brazi 1 ) , Carlson, A. D., Johnson, R. G. , and

Wasson, 0. A., Application of the Dual Thin Scintillator Neutron Flux

Monitor in a 235 U(n,f) Cross Section Measurement, Proceedings of the

International Atomic Energy Agency (IAEA) Advisory Group Meeting on Nuclear Standard Reference Data, Nov. 12-16, 1984, Geel, Belgium, IAEATECD0C-335, 467 (1985).

Dias, M. S., Johnson, R. G., and Wasson, 0. A., Design and Calibration of

an Absolute Flux Detector for 1-15 MeV Neutrons, Nucl. Instr. Meth. 224,

532-546 (1984).

Dick, C. E., Soares, C. G., Pruitt, J. S., and Sparrow, J. H., Development

of Monoenergetic Electron Beam Sources for Radiation Instrument

Calibration, Nucl. Instr. Meth. in Phys. Res. B 10/ 11 , 937 (1985).

Dick, C. E., Polansky, D., Soares, C. G., and Seltzer, S. M., Radiation

Measurements on a Portable 1.5 MeV Linac, NBSIR 85-3209 (1985).

217
Division 536, Publications (cont'd.)

Dizdaroglu, M., Gajewski, E., and Simic, M. G. , "Enzymatic Digestibility

of Peptides Crossl inked by Ionizing Radiation", Int. J. Radi at. Biol. 45,

283-295 (1984). ~

Dizdaroglu, M., and Simic, M. G., Radiation-induced Crosslinks Between

Thymine and Phenylalanine. Int. J. Radiat. Biol. _£7_, 63 (1985).

Dizdaroglu, M. and Simic, M. G., Radiation-induced Crosslinking of

Cytosine, Rad. Res. 100, 41 (1984).

Dizdaroglu, M., The Use of Capillary Gas Chromatography-Mass Spectrometry

for Identification of Radiation-Induced DNA Base Damage and DNA Base-Amino

Acid Crosslinks, J. Chromatogr. 295, 103-121 (1984).

Dizdaroglu, M., Separation of Sequence Isomeric Dipeptides by HighResolution Gas Chromatography, J. Chromatogr. 318, 384-386 (1985).

Dizdaroglu, M., Gajewski, E., and Simic, M. G., Radiation-Induced

Formation of Thymi ne-thymi ne Crosslinks, Int. J. Radiat. Biol. 46, 241

(1984). —

Dizdaroglu, M., Application of Capillary Gas Chromatography-Mass

Spectrometry to Chemical Characteri zation of Radiation-Induced Base Damage

of DNA: Implications for Assessing DNA Repair Processes, Anal. Biochem.

144, 593-603 (1985).

Dizdaroglu, M., Peptide Separations by Hi gh-Performance Ion-Exchange

Chromatography , Handbook of HPLC for the Separation of Amino Acids,

Peptides and Proteins, Baco Raton: CrC Press, Ed. W.S. Hancock, II, 23-44

(1984)

.

Dizdaroglu, M., Weak Anion-Exchange Hi gh-Performance Liquid Chromatography

of Peptides, J. Chromatogr. Chrom. Rev. 334, 49-69 (1985).

Duvall, K. C., Carlson, A. D., and Wasson, 0. A., Calibration of the NBS

Black Neutron Detector at 2.3 MeV Using the Time-Correlated AssociatedParticle Method, Nucl. Instr. Meth. B 10/ 11 , 931-933 (1985).

Duvall, K. C., Soares, C. G, Heaton, H. T. II, and Seltzer, S. M., The

Development of a 6 to 7 MeV Photon Field for Instrument Calibration, Nucl.

Instr. Meth. in Phys. Rev. B10/11 , 942-945 (1985).

Duvall, K. C., Carlson, A. D., and Wasson, 0. A., Measurement of the NBS

Black Neutron Detector Efficiency at 2.3 MeV, Proceedings of the

International Atomic Energy Agency (IAEA) Advisory Group Meeting on Nuclear Standard Reference Data, Nov. 12-16, 1984, Geel, Belgium,

IAEA-TECD0C-335, 332 (1985).

218
Division 536, Publications (cont'd.)

Eisenhauer, C. M. and Schwartz, R. B., Analysis of Measurements with

Personnel Dosimeters and Portable Instruments for Determining Neutron

Dose Equivalents at Nuclear Power Plants, Nuclear Regulatory Commission

Report NUREG/CR-3400 (1983).

Eisenhauer, C. M., Evaluation of Dose Equivalent per Unit Fluence for a

D

2 0-Moderated 252 Cf Neutron Source, Radiation Protection Dosimetry _9,

63-64 (1984).

Eisenhauer, C., Hunt, J. B., and Schwartz, R. B., Calibration Techniques

for Neutron Personal Dosimetry, Radiation Protection Dosimetry _10, 43-57

(1985).

Eisenhauer, C. M., and Verbinski, V., Use of Activation Detectors to

Characterize a Neutron Environment, Proc. Fifth ASTM-EURATOM Symposium on Reactor Dosimetry, Geesthact, West Germany, September 24-28, 1964 (1985).

Gajewski, E., Dizdaroglu, M., Krutzsch, H. C., and Simic, M. , OH Radical

Induced Crosslinks of Methionine Peptides, Int. J. Radiat. Biol. 46, 47,

(1984).

Gerstenberg, H. and Hubbell, J., Comparison of Experimental with

Theoretical Photon Attenuation Cross Sections 10 eV to 100 GeV, Proc.

International Conference on Nuclear Data for Science and Technology, Sept.

6-10, 1982, Antwerp, Belgium, 1007-1009 (1984).

Gilliam, D. M., Grundl, J. A., Lamaze, G., Eisenhauer, C. M., and

Fabry, A., Cross Section Measurements in the 235 U Fission Spectrum Neutron

Field, Proc. Fifth ASTM-EURATOM Symposium on Reactor Dosimetry,

Geesthacht, West Germany, September 24-28, 1984 (1985).

Goodman, L. J., Coyne, J. J., and Caswell, R. S., The Programme of the

United States National Bureau of Standards in Dosimetry Standards for

Neutron Radiation Therapy, Proc. of IAEA Int. Symposium on Advances in

Dosimetry for Fast Neutrons and Heavy Charged Particles for Therapy

Applications, Vienna, Austria, IAEA-AG-371/8, 217-227 (1984).

Goodman, L. J., A Practical Guide to Ionization Chamber Dosimetry at the

AFRRI Reactor, Armed Forces Radiobiology Research Institute, Bethesda, MD

( 1985) 41 pp.

Goodman, L. J., The Future of A-150 TE Plastic, Proceedings of the Fifth

Symposium on Neutron Dosimetry, Munich, West Germany, Sept. 17-21, 1984,

Commission of the European Communities Report EUR 9762 II, 687-694

(1985). ~

Haight, R. C., Grimes, S. M., Johnson, R. G., and Barschall, H. H., The

12 C(n,a) Reaction and the Kerma Factor for Carbon at E n = 14.1 MeV, Nucl.

Sci. Eng. 87, 41-47 (1984).

219
Division 536, Publications (cont'd.)

Hartmann, G. H., Coyne, J. J., Mohart, A., Schuhmacher, H., and

Menzel, H. G., Response of Tissue-Equivalent Proportional Counters to

Neutrons and to Mixed Radiation Fields, Workshop on Practical

Implementation of Microdosimetric Counters in Radiation Protection,

Homburg/Saar, West Germany, May 14-18, 1984, Rad. Prot. Dosim. 9 (3), 207

210 (1984).

Hoppes, D.D., Basic Radionuclide Measurements at the U.S. National Bureau

of Standards, Environment International JT), 99-107 (1984).

Hubbell, J., A Rectangular Source (Problem and Solution Section), SIAM

Review 25, 267 (1983).

Hubbell, J., Photon Attenuation Coefficient and Cross Section Data 100 eV

to 100 GeV. Current Status and Prospects, Proc. 2nd International

Symposium on Radiation Physics, May 25-29, 1982, Penang, Malaysia, 15-27

(1984).

Hutchinson, J. M. R. and Colie, R., Development of a Radon Flux Density

Standard, Health Physics Society Annual Meeting, Chicago, Illinois, May

26-31, 1985 (Abstract Only.)

Hutchinson, J. M. R. and Bortels, G., Concluding ICRM Session, Nucl.

Instrum. Meth. 223, 617-618 (1984).

Hutchinson, J. M. R., Mullen, P. A., and Colle, R., Development of a Regenerative Radon-in-Water Radioactivity Standard, Nucl. Instrum. Meth.

in Physics Research 223, 451-457 (1984).

Inn, K. G. W., Mullen, P. A., and Hutchinson, J. M. R., Radioactivity

Standards for Environmental Monitoring II., Environment International _10,

91-97 (1984).

Inn, K. G. W., Liggett, W. S., and Hutchinson, J. M. R., Statistical

Assessment of Subsampling Procedures, Environment International _10, 143-

151 (1984).

Inn, K. G. W., Liggett, W. S., and Hutchinson, J. M. R., The National

Bureau of Standards Rocky Flats Soil Standard Reference Material, Nucl.

Instrum. Meth. in Physics Research 223, 443-450 (1984).

Jovanovic, S. V. and Simic, M. G., Repair of Tryptophan Radicals by

Antioxidants, J. Free Radicals in Biol. & Med. _1» 125 (1985).

Karam, L., Dizdaroglu, M., and Simic, M. G., OH Radical -induced Products

of Tyrosine Peptides, Int. J. Radiat. Biol. 46, 715 (1984).

220
D i v i si on 536, Publications (cont'd.)

Kronenberg, S., Markow, B., McLaughlin, W. L., and Siebentritt, C. R.,

Radiochromic Waveguide Dosimetry - A New Research Tool with Radiation

Applications, Proceedings of U.S. Army Science Conference, West Point, NY

June 19-21, 1984 (1985).

Lamaze, G. P., Gilliam, D. M., McGarry, E. D., and Fabry, A., Neutron

Fluence and Cross Section Measurement for Fast Neutron Dosimetry,

Proceedings of Fifth International Conference on Nuclear Methods in

Environmental and Energy Research, San Juan, Puerto Rico, April 1984, DoE

Publication C0NF-840408, 593-601 (1985).

Loevinger, R., Seltzer, S. M., and Heaton, H. T., The Physics and

Mathematics of Beta Particle Dosimetry, Proc. of the Inti. Beta Dosimetry

Symposium, Washington, D.C., Feb. 15-18 1983, NUREG/CP-0050, 1-14 (1984).

Loevinger, R., The AAPM Accredited Dosimetry Calibration Laboratory,

Proc. Workshop on Radiation Survey Instruments and Calibrations, NBS,

Gaithersburg, MD, 1984, U.S. Department of Energy (1985).

Mann, W. B., Editor, A Handbook of Radioactivity Measurements Procedures , National Council on Radiation Protection and Measurements, NCRP Report 58

(February 1985)

.

Margolis, S. and Dizdaroglu, M., Separation and Purification of

Di astereomers of Angiotens I by Anion-Exchange Hi gh-Performance Liquid

Chromatography, J. Chromatogr. 322 , 117-128, (1985).

McGarry, E. D., Gilliam, D. M., Lamaze, G., Eisenhauer, C. M., and

Fabry, A., The U. S. 235 U Fission Spectrum Standard Neutron Field

Revisited, Proc. Fifth ASTM-EURATOM Symposium on Reactor Dosimetry,

Geesthact, West Germany, Sept. 24-28, 1984 (1985).

McLaughlin, W. L., and Humphreys, J. C., Radiochromic Dye Dosimetry Using

Tri phenylmethane Leucocyanides in Nylon or Polyvinyl Butyral, IAEA

Technical Report on High-Dose Standardization and Intercompari son for

Industrial Radiation Processing, 209-236 (1984).

McLaughlin, W. L., Buenfi 1 -Burgos, A. E., Uribe, R. M., de la Piedad, A.,

and Miller, A., Thin Plastic Radiochromic Dye Films as Ionizing Radiation

Dosimeters, Rad. Phys. Chem. _23, 325-332, (1984).

McLaughlin, W. L., Miller, A., and Uribe, R. M., Radiation Quality Control

for Food Preservation and Disinfestation, Rad. Phys. Chem. 23, 21-29,

(1984). ~

McLaughlin, W. L., Uribe, R. M., and Miller, A., Megagray Dosimetry,

Monitoring of Very Large Radiation Doses, Rad. Phys. Chem. 23, 333-362,

(1984). ~

221
Division 536, Publications (cont'd.)

McLaughlin, W. L., Uribe, R. M., and Chappas, W. J., Improvement of

Radiochromic Film Dosimetry Precision by Individual Dosimeter

Characterization, Int. J. Appl . Radi at. Isot. _35_, 995-997 (1984).

McLaughlin, W. L, Alian, A., El-Assy, N. B., Abdel Rehim, F., Amin, N. E.,

and Roushdy, H., Chemical Dosimetry by UV Spectrophotometry of Aqueous

Ascorbic Acid Solutions, Rad. Phys. Chem. 23 , 435-440 (1984).

McLaughlin, W. L., Humphreys, J. C., Farahani, M., and Miller, A.,

Measurement of High Doses Near Metal and Ceramic Interfaces, Proc.

Symposium on High-Dose Dosimetry, Oct. 11-12, 1984, Internati onal Atomic

Energy Agency, Vienna, 109-133 (1985).

McLaughlin, W. L., Chen, W., and Jia, H., Response of Radiochromic Film

Dosimeters to Electron Beams in Different Atmospheres, Proc. Symposium on High-Dose Dosimetry, Oct. 11-12, 1984, International Atomic Energy Agency,

Vienna, 345-356 (1985).

McLaughlin, W. L., Standardization of High-Dose Measurement of Electron

and Gamma Ray Absorbed Doses and Dose Rates, Proc. Symposium on High-Dose

Dosimetry, Oct. 11-12, 1984, International Atomic Energy Agency, Vienna,

357-371 (1985).

McLaughlin, W. L., Miller, A., Uribe, R. M., Kronenburg, S., and

Siebentritt, C. R., Energy Dependence of Radiochromic Dosimeter Response

to X- and Gamma Rays, Proc. Symposium on High-Dose Dosimetry, Oct. 11-12,

1984, International Atomic Energy Agency, Vienna, 397-424 (1985).

Menzel, H. G., Hartmann, G. H., Dudler, R., Schuhmacher, H., and

Coyne, J. J., Physical Aspects of Using Rossi -Proportional Counters for

Radiation Protection Measurements and Practical Development, Proc. 6th

International Congress of the International Radiation Protection

Association, Berlin (1984).

Miller, A. and McLaughlin, W. L., Measurement of Absorbed Doses and Dose

Distributions, Proc. 2nd International Symposium on Radiation Processing

for Plastics and Rubber, Canturbury, England (1984); J. Indust. Radiat.

Tech. 3 , 340-350 (1984)

.

Oliver, B. M., Farrar IV, H., Gilliam, D, M., and Lippincott, E. P.,

Spectrum-Integrated Helium Generation Cross Section for 6 Li and 10 B in the

Immediate-Energy Standard Neutron Field, Proc. Fifth ASTM-EURATOM

Symposium on Reactor Dosimetry, Geesthacht, Germany, Sept. 24-28, 1984

(1985).

Petilli, M., Gilliam, D. M., Evaluation of Uncertainties of 235 U Fission

Spectrum, Proc. Fifth ASTM-EURATOM Symposium on Reactor Dosimetry,

Geesthacht, Germany, Sept. 24-28, 1984 (1985).

222
Division 536, Publications (cont'd.)

Pruitt, J. S., Soares, C. G. , and Ehrlich, M., Standard Beta-Particle and

Monoenergetic Electron Sources for the Calibration of Beta-Radiation

Protection Instruments, NUREG/CR-4266, NBSIR 85-3169 (September 1985).

Radak, B. B. and McLaughlin, W. L., The Gamma-ray Response of "Optichromic Dosimeters", Rad. Phys. Chem. _23_, 673-675 (1984).

Schima, F. J., Martins, M. N., Hayward, E., Lamaze, G., and Maruyama,

X. K., Experimental Test of the Bremsstrahl ung Cross Section, Phys. Rev. C

30(1984).

Schima, F. J., Hurst, G. S., Chen, C. H., Kramer, S. D., Davis, R., Jr.,

Cleveland, B., and Gabbard, F., Feasibility of the 81 Br(v,e") 81 Kr Solar

Neutrino Experiment, Phys. Rev. Lett. _53_, 1116-1119 (1984).

Schrack, R. A., A MicroChannel Plate Neutron Detector, Nucl. Instr.

Meth. 222, 499-506 (1984).

Schrack, R. A., U -235 Measurement in Waste Material by Resonance Neutron

Radiography, Nucl. Tech. _67_, 326 (1984).

Schuhmacher, H., Menzel, H. G., and Coyne, J. J., Critical Evaluation of

Neutron Kerma Factors Using Theoretical and Experimental Ionization Yield

Spectra, Proc. Fifth Symposium on Neutron Dosimetry in Munich, September

17-21, 1984, Commission of the European Communities, EUR 9762 j_, 213-224

(1985).

Seltzer, S. M. and Berger, M. J., Improved Procedure for Calculating the

Collision Stopping Power of Elements and Compounds for Electrons and

Positrons, Inti. J. Appl . Radiat. Isot. 35^, 665-676 (1984).

Seltzer, S. M. and Berger, M. J., Electron and Photon Transport in MultiLayer Media: Notes on the Monte Carlo Code ZTRAN, NBSIR 84-2931 (1984).

Siebert, B. R. L. and Coyne, J. J., Dose Conversion Factors and W

N Values

for Infinitesimal and Infinite Tissue Equivalent Ion Chambers in

Monoenergetic Neutron Fields from Thermal to 20 MeV, Workshop on Practical

Implementation of Microdosimetric Counters in Radiation Protection,

Homburg/Saar , West Germany, May 14-18, 1984, Rad. Prot. Dosim. 9 (3), 215-

218 (1984).

Simic, M. G. and Hunter, E. P. L., The Reactivities of Organic Oxygen

(Oxy) Radicals, Oxygen Radicals in Chemistry and Biology , Eds. Bors, W.,

Saran, M., and Tait, D., W. De Gruyter & Co., 109 (1984).

Simic, M. G. and Dizdaroglu, M., Formation of Radiation-induced Crosslinks

Between Thymine and Tyrosine: A Possible Model for the Crosslinking of DNA

and Proteins by Ionizing Radiation, Biochem. 24, 233 (1985).

223
Division 536, Publications (cont'd.)

Simic, M. G. , Dosimetry - Measure of Dosage Received, Food Processors

Institute Proceedings _25_ ( 1985).

Simic, M. G., Gajewski, E., and Dizdaroglu, M., Kinetics and Mechanisms of

OH Radical Induced Crosslinks Between Phenylalanine Peptides, Radi at.

Phys. Chem. 24, 465 (1985).

Soares, C. G., Dick, C. E., Pruitt, J. S., and Sparrow, J. H., Development

of Monoenergetic Electron Beam Sources for Radiation Instrument

Calibration, Nucl. Inst. Meth. B1 0/1

1

, 937-941 (1985).

Sternheimer, R., Seltzer, S. M., and Berger, M. J., Density Effect for the

Ionization Loss of Charged Particles in Various Substances, Atomic Data

and Nuclear Data Tables 30, 261-271 (1984); also NBSIR 83-2785.

Trochon, J., Simon, G., Behrens, J. W., and Brisard, F., "Cold

Fragmentation" Measurements Using a Very-Hi gh-Energy Resolution Ionization

Chamber, Trans. Am. Nucl. Soc. 49_, 199 (June 1985).

Wilson, W. E., McDonald, J. C., Coyne, J. J., and Paretzke, H. G., Monte

Carlo Calculation of Energy Deposition and Ionization Yield for High

Energy Protons, Proc. Fifth Symposium on Neutron Dosimentry, Munich, West

Germany, September 17-21, 1984, Commission of the European Communities,

EUR 9762 U 237-244 (1985)

.

Yin, Lo I, Bielefeld, M. J., Seltzer, S. M., and Trombka, J. 1.,

Tomographic and 3-D Simulations Using NORA, J. Appl . Optics _23_, 2239-2241

(1984).

Zhan-Jun, L., Radak, B.B., and McLaughlin, W.L., Food Irradiation

Dosimetry by Opti -Chromic Technique, Int. J. Rad. Phys. Chem., _25_, (1985).

’

224
PUBLICATONS IN PREPARATION

Division 536, Ionizing Radiation

AlShiekhly, M. and McLaughlin, W.L., A pulse-radiolysis study of the

mechanism of radiolytic dye formation in liquid solutions of hexa

(hydroexyethyl ) pararosani 1 i ne cyanide, to be submitted to the Journal of

the American Chemical Society.

Barnea, G. and Dick, C. E., Monte Carlo Studies of X-Ray Scattering in

Transmission Diagnostic Radiology (in preparation)

.

Barnea, G., Berger, M. J., and Seltzer, S. M., An Optimization Study of

Electron-Bremsstrahl ung Shielding for Manned Spacecraft (in preparation)

.

Barnea, G., Seltzer, S. M., and Berger, M. J., Transport of Electrons and

Associated Bremsstrahlung Through a Composite Aluminum-Lead Shield with

Applications to Spacecraft Shielding (in preparation)

.

Barnea, G. and Dick, C. E., Coupled Electron/Photon Monte Carlo Calculations of X-Ray Scattering with Application to Industrial Radiography (in

preparation)

.

Berger, M. J., Energy Loss Straggling of Protons in Water Vapor, Radiat.

Protection Dosimetry (in press).

Bergtold, D. S., Williams, G. R., and Lett, J. T., Structural Alterations

of DNA from Rabbit Photoreceptors During Aging, Age (in press).

Bergtold, D. S. and Lett, J. T., Alterations in Chromosomal DNA and Aging:

An Overview, in: The Molecular Biology of Aging: Gene Stability and Gene

Expression, R. S. Sohal, L. Birnbaum and R. G. Cutler, eds., (Raven

Press) (1985) .

Burger, G. and Schwartz, R. B., Guidelines for the Establishment and

Operation of a Secondary Standard Dosimetry Laboratory for Neutrons, IAEA

Technical Reports Series (in press).

Carlson, A. D., New Measurements of the Ratio of the 10 B(n,a) to 6 Li(n,t)

Cross Sections in the eV Energy Region, Radiation Effects (to be

publ ished)

.

Carlson, A. D., Poenitz, W. P., Hale, G. M., and Peelle, R. W., The

Neutron Cross Section Standards Evaluation of ENDF/B-VI, Radiation Effects

(to be published).

225
Oivision 536, Publications in Preparation (cont'd.)

Caswell, R. S., Nuclear Data for Biomedical Applications, Proc. Conference

on Nuclear Data for Basic and Applied Science, Santa Fe, NM, May 13-17,

1985 (in press).

Creagh, D. C. and Hubbell, J. H., Problems Associated with the Measurement of X-ray Attenuation Coefficients: Report on the IUCr X-ray Attenuation Project, Acta Cryst. A (in press).

Dias, M. S., Carlson, A. D., Johnson, R. G., and Wasson, 0. A., Application of the Dual Thin Scintillator Neutron Flux Detector in a 235 U(n,f)

Cross Section Measurement (in preparati on)

.

Dizdaroglu, M., Formation of an 8-Hydroxyguani ne Moiety in

Deoxyribonucleic Acid on Irradiation in Aqueous Solution, Biochemistry

(in press)

.

Dizdaroglu, M. and Simic, M. G., Radiation-induced Crosslinking of

Pyrimidine Oligonucleotides, Radiat. Phys. Chem. (in press).

Dizdaroglu, M., Simic, M. G., and Karam, L. R., Chemical Analysis of

Irradiated Foods, Trans. Am. Nucl. Soc. (in press).

Domen, S. R., Advances in Calorimetry for Radiation Dosimetry. In: Techniques in Radiation Dosimetry , Vol . 2, edited by K.R. Kase, F.H.

Attix, and B.E. Bjarngard, Academic Press, (in press).

Duvall, K. C., Johnson, R. G., The Development of the Dual Thin

Scintillator (DTS) in the 1+2 Coincidence Configuration as a Neutron

Spectrometer, Radiation Effects (in press).

Eisenhauer, C. and Grundl, J., First Evaluation of ISNF Spectra Based on Interl aboratory Computation, LWR PV Progress Report, NUREG/CR (in press)

Fiorito, R. B., Raleigh, M., and Seltzer, S. M., Current Density Monitor

for Intense Relativistic Electron Beams, (in press)

Grundl, J. A., Examination of 10 B(n,He) and 6 Li(n,He) Cross Section

Measurements in Reactor Physics Benchmarks, Proc. International Conf.

on Nuclear Data for Basic and Applied Science, Santa Fe, NM, May 13-17,

1985 (in press)

.

Hubbell, J. H., Photon Cross Sections 1 keV to 100 GeV. Current NBS

Compilation (to be presented at the ANS Winter meeting, Nov. 10-14, 1985,

San Francisco, CA and published in the ANS Trans.).

Johnson, R. G., and Schrack, R. A., Nondestructive Evaluation of M732

Proximity Fuzes, NBS Interagency/Internal Report (NBSIR) (in press).

226
Division 536, Publications in Preparation (cont'd.)

Johnson, R. G., and Phillips, T. W. (LLNL), Comment on the Evidence for

Electric Quadrupole Strength in 16 0 from the Photoneutron Reaction,

Phys. Rev. C Comments (in press).

Johnson, R. G., Conceptual Design of an Induction Linac for Neutron

Research, Radiation Effects (to be published).

Jovanovic, S. and Simic, M. G., Tryptophan Metabolites as Antioxidants,

Free Radicals in Chemistry and Biology (in press).

Jovanovic, S. V., Neta, P., and Simic, M.G., One-electron Redox Reactions

of Pyrazal i n-5-ones, A Pulse Radiolysis of Antipyrine and Analogues,

Molecular Pharmacology (in press).

Kalla, S. L., Conde, S., and Hubbell, J. H., Some Results on Generalized

Elliptic-type Integrals, Math, of Comp, (in press).

Karam, L. R., Simic, M. G., and Dizdaroglu, M., Free-radical Induced

Cross-linking of Polydeoxythymi dyl i c Acid in Deoxygenated Aqueous

Solution, Int. J. Radiat. Biol, (in press).

Lett, J. T., Bergtold, D. S., and Keng, P. C., Fate in situ of DNA Damage

Induced in Rabbit Sensory Cells by Ionizing Radiations of Different LET'S

In: Proceedings of the International Conference on Mechanisms of DNA

D am age and Repair, NBS, Gai thersburg, MD, June 1985, M. G. Simic, ed.

Lett, J. T. Cox, A. B., and Bergtold, D. S., Cellular and Tissue Responses

to Heavy Ions: Basic Considerations, Radiation and Environmental

Biophysics (1985) (in press).

" ~

Lett, J. T., Bergtold, D. S., and Keng, P. C., DNA damage and its repair

in rabbit sensory cells. In: Mechanisms of DNA Damage and Repair:

Implications for Carcinogenesis and Risk Assessment,!^. G. Simic, L

.

Grossman and A. D. Upton, eds., (Academic Press: New York). 1985 (in

press)

.

McDonald, J. C., and Domen, S. R., A-150 Plastic Radiometric Calorimeter

for Charged Particles and Other Radiations, Nucl. Instr. Meth. (in

preparation)

.

McLaughlin, W. L., Radak, B. B., Silverman, J., Liu Zhan Jun, Miller, A.,

Bastberg-Pedersen, W., and Charlesby, A., High Density Polyethlene Film

Dosimetry by Infrared Spectrophotometry of Transvinylene Unsaturation, to

be submitted to Radiation Physics and Chemistry (1985).

227
Division 536, Publications in Preparation (cont'd.)

McLaughlin, W. L., Radak, B. B., and Farahani, M., "Measurement Quality

Assurance in the Radiation Treatment of Foods, Trans. Am. Nucl. Soc. (in

press)

.

Neta, P. and Simic, M. G., Free Radical Chemistry of Natural Products,

Inst. Food Tech, (in press).

Pruitt, J. S., The Effect of Altitude on Beta-Ray Source Calibrations,

Rad. Protect. Dosim. (in press).

Radak, B. B., McLaughlin, W. L., and Simic, M. G., Enhanced Sensitivity of

Chemical Dosimeters Using Liquid Core Optical Wave Guides, submitted to

Nuclear Instruments and Methods (1985).

Schrack, R. A., A MicroChannel Plate Neutron Detector, Chapter in

International Advances in Nondestructive Testing (in press).

Schrack, R. A., New Applications of Resonance Neutron Radiography,

Radiation Effects (to be published).

Schroder, I. G., Linpei, Li, Gilliam, D. M., McGarry, E. D. and

Eisenhauer, C. E., Measurement of Absolute Fission Cross Sections for

252 Cf Spontaneous Fission Neutrons, Nuclear Trans, (in press).

Schwartz, R. B., Guidelines for the Establishment and Operation of a Secondary Standard Dosimetry Laboratory for Neutrons, IAEA Technical

Reports Series (in press).

Seltzer, S. M. and Berger, M. J., Bremsstrahl ung Spectra from Electron

Interactions with Screened Atom Nuclei and Orbital Electrons, Nucl. Instr

Methods B (in press).

Seltzer, S. M. and Berger, M. J., Bremsstrahl ung Energy Spectra from

Electrons with Kinetic Energy 1 keV-10 GeV Incident on Screened Nuclei and

Orbital Electrons of Neutral Atoms with Z = 1 - 100, Atomic Data & Nucl.

Data Tables (in press)

.

Simic, M. G. and Hunter, E. P. L., Antioxidants, Inst. Food Tech, (in

press )

.

Simic, M. G., Free-radical Mechanisms of DNA Base Damage, International

Conference on Mechanisms of DNA Damage and Repair, NBS, Gaithersburg, MD,

June 7, 1985, J. Res. NBS (in press).

Trochon, J., Simon, G., Behrens, J. W., Brisard, F., and Signarbieux, C.,

Cold Fragmentation in Thermal Neutron Fission at 235 U, Radiation Effects

( to be publ i shed)

.

228
0 i v i sion 536, Publications in Preparation (cont'd.)

Wasson, 0. A., Progress in the Detection of Low-Energy Neutrons,

Proc. 4th International Symposium on Neutron-Induced Reactions, Smolenice,

Czechoslovakia, June 17-21, 1985 (in press).

Wasson, 0. A., Carlson, A. D., and Duvall, K. C., Analysis of the Effect

of Random Events on the 14 MeV U-235(n,f) Cross Section Measurement,

Radiation Effects (to be published).

229
TECHNICAL AND PROFESSIONAL COMMITTEE PARTICIPATION AND LEADERSHIP

Division 536, Ionizing Radiation

James W. Behrens

Chairman, Nuclear Data Committee of the Isotopes and Radiation

Division, American Nuclear Society.

Member, Transuranic Task Force, of the Isotopes and Radiation

Division, American Nuclear Society.

Member, Cross Section Evaluation Working Group, National Nuclear

Data Center, Brookhaven National Laboratory.

Martin J. Berger

Member, International Atomic Energy Agency Advisory Group on Nuclear

and Atomic Data for Radiotherapy and Radiobiology.

Chairman, International Commission on Radiation Units and

Measurements (ICRU), Committee on Stopping Power.

Member, National Council on Radiation Protection and Measurements

(NCRP), Committee #52 on Conceptual Basis of Dosimetry.

Member, NCRP, Committee #55 on Experimental Verification of Internal

Dosimetry

.

Member, Naval Surface Weapons Center Laboratory Review Team of the

Naval Research Advisory Committee Panel on Laboratory Oversight.

Member, Naval Research Advisory Committee, Naval Surface Weapons

Center Review Panel

.

Jacquel ine M. Calhoun

Member, National Measurements Laboratory Minority Advisory Panel.

EEO Counselor, NBS, two-year appointment, January 19, 1984 through

January 19, 1986.

Allan D. Carlson

Member, Cross Section Evaluation Working Group (CSEWG).

Member, Evaluation Committee of CSEWG.

230
Division 536, Technical and Professional Committee Participation and

Leadership (cont'd.)

Allan D. Carlson (cont'd.)

Chairman, Standards Subcommittee, CSEWG.

Member, Data Status and Requests Subcommittee of CSEWG.

Member, Organizing Committee for the International Atomic Energy

Agency Advisory Group Meeting on Nuclear Standard Reference Data

held in Geel, Belgium, Nov. 12-16, 1984.

Randall S. Caswell

Chairman, Science Panel, Committee on Interagency Radiation Research

and Policy Coordination (CIRRPC), Office of Science and Technology

Policy.

Alternate Member, CIRRPC, Office of Science and Technology Policy.

Delegate, Consultative Committee for Ionizing Radiations (CCEMRI),

Conference G$n£ra1e des Poids et Mesures, Paris, France.

Chairman, Section on Neutron Measurements (Section III), CCEMRI,

Conference Generale des Poids et Mesures, Paris, France.

Member, National Council on Radiation Protection and Measurements

(NCRP)

.

Chairman, NCRP Ad Hoc Committee on SI Units.

Chairman, NCRP Ad Hoc Committee on Publications.

Member and Secretary, International Commission on Radiation Units and

Measurements (ICRU).

Sponsor, ICRU Report Committee on Stopping Power.

Sponsor, ICRU Report Committee on Absolute and Relative Dosimetry at

High Doses.

Sponsor, ICRU Report Committee on Tissue-Equivalent Materials.

Member, Radiation Research Accelerator Facility (RARAF) Scientific

Advisory Committee, Columbia University.

231
Division 536, Technical and Professional Committee Participation and

Leadership (cont'd.)

Ronald Co 11 $

Member, Science Subpanel on Radon Protection and Health Effects,

Committee on Interagency Radiation Research and Policy Coordination.

Member, Radon Working Group, Interagency Committee on Indoor Air

Qual i ty.

Delegate, Bureau International des Poids et Mesures (BIPM) Working

Group on the Statement of Uncertainties.

Resource Person, Conference of Radiation Control Program Directors,

Subcommittee on Radon Measurements.

Resource Person, Conference of Radiation Control Program Directors,

Task Force on Criteria for an Adequate Radiation Control Program - Environmental Monitoring and Surveillance.

Bert M. Coursey

Member, International Committee for Radionuclide Metrology (ICRM)

Life Sciences Working Group

Member, ANSI Subcommittee N42.2 on Procedural Standards for

Calibration of Detectors for Radioactive Materials.

J. Joseph Coyne

Member, CIRRPC Subcommittee on High LET Radiation.

Member, European Community Dosimetry Group (EURADOS) Committee 1: Tissue-Equivalent Proportional Counters as an Instrument for

Radiation Protection.

Member, EURADOS Committee 4: Computational Methods and Benchmark

Calculations in Radiation Protection.

Member, International Atomic Energy Agency Advisory Group on Nuclear

and Atomic Data for Radiotherapy and Radiobiology.

Charles E. Dick

Member, Technical Program Committee, Biannual Conferences on Applications of Small Accelerators in Industry and Medicine.

232
Division 536, Technical and Professional Committee Participation and

Leadership (cont'd.)

Margarete Ehrlich

Member, ISO/TC 85/SC 2/WG 2, Photographic Dosimeters and Reference

Radi at ion.

Member, Health Physics Society Standards Committee N13.28, Work Group

on Criteria for Testing Environmental Dosimetry Performance.

Member, Work Group on Revision of ANSI/ANS 6.1.1, Neutron and GammaRay Flux-to-Dose Rate Factors, American Nuclear Society.

Member, National Research Council, Commission on Life Sources,

Committee on Dose Assignment and Reconstruction for Service Personnel

at Nuclear Weapons Test.

Charles M. Eisenhauer

Alternate Member, CIRRPC Science Panel.

Member, National Council on Radiation Protection and Measurements

(NCRP) Task Group on Atomic Bomb Survivor Dosimetry: SC-40

Biological Aspects of Radiation Protection Criteria.

Member, ASTM Subcommittee E10.05 on Nuclear Radiation Metrology.

Member, NAS-NRC Advisory Committee on the Radiation Effects Research

Foundation Subcommittee: Panel on the Reassessment of A-Bomb

Dosimetry.

Member, ANS Standards Committee Working Group on Gamma-Ray

Attenuation Data.

Elmer H. Eisenhower

Alternate Representative, ANSI N44, Equipment and Materials for

Medical Radiation Applications.

Chairman, ANSI N43, Equipment for Non-Medical Radiation Applications.

Chairman, Interagency Committee on Occupational Radiation Protection

Measurements.

Resource Person, Conference of Radiation Control Program Directors,

Committee on Radiation Measurements.

Department of Commerce Representative, Interagency Working Group on Occupational Exposure Guidance.

233
Division 536, Technical and Professional Committee Participation and

Leadership (cont'd.)

Elmer H. Eisenhauer (cont'd.)

Member, ASTM Subcommittee E10.04 on Radiation Protection

Methodology.

Member, Science Subpanel on Scientific Basis for Radiation Protection

Standards, Committee on Interagency Radiation Research and Policy

Coordination.

Member, Committee on Secondary Calibration Laboratories for Survey

Instruments, Health Physics Society.

Leon J. Goodman

Member, Report Committee on Clinical Dosimetry for Neutrons,

International Commission on Radiation Units and Measurements.

Consultant, American Association of Physicists in Medicine, Task

Group No. 18, Fast Neutron Beam Dosimetry Physics, Radiation Therapy

Committee for AAPM Report No. 7, Protocol for Neutron Beam

Dosimetry .

James A. Grundl

Member, Steering Committee for Developing ASTM Standards for Reactor

Dosimetry, NBS, March 1985.

Member, ASTM Subcomittee E10.05 on Nuclear Radiation Metrology.

H. Thompson Heaton, II

Member, ANSI N43-3.4, Subcommittee for Gamma Irradiators.

Member, ANSI N43-8, Subcommittee for Electron Microscopes.

Resource Person, Conference of Radiation Control Program Directors,

Committee on Radiation Measurements.

Dale D. Hoppes

Member, International Committee for Radionuclide Metrology (ICRM)

Alpha-, Beta, and Gamma-Ray Spectrometry Working Group.

Member, Atomic Industrial Forum (AIF)-NBS Standards Program

Commi ttee.

234
Division 536, Technical and Professional Committee Participation and

Leadership (cont'd.)

Dale D. Hoppes (cont'd.)

Member, International Committee of Weights and Measures (BIPM),

Consultative Committee on Standards for Measuring Ionizing

Radiations, Subcommittee Section II: Radionuclide Measurements.

Member, ANSI Subcommittee N42.2 on Procedural Standards for

Calibration of Detectors for Radioactive Materials.

John H. Hubbell

Secretary, Commission on Crystal lographic Apparatus, International

Union of Crystal 1 ography. Task Group on X-Ray Absorption

Coefficients.

Chairman, American Nuclear Society (ANS) Radiation Protection and

Shielding Division ANS-6 Ad Hoc Committee on SI Units.

Member, Cross Section Evaluation Working Group (CSEWG) Subcommittee

on Shielding.

Secretary, Pro-tern Committee, now-forming International Radiation

Physics Society.

Acting Chairman, ANS Isotopes and Radiation Division Nuclear Data

Committee.

Chairman, General Health Physics Section of the Health Physics

Society Standards Committee.

Secretary, International Program Committee for the 3rd International

Symposium on Radiation Physics, Ferrara, Italy, Sept. 30-0ct. 4,

1985.

Jimmy C. Humphreys

Secretary, ASTM Committee E10.07, Ionizing Radiation Dosimetry and

Radiation Effects on Materials and Electronic Devices.

Member, ASTM-F-1.11, Subcommittee on Quality and Hardness Assurance

of the F-l Electronic Committee.

Member, Association for Advancement of Medical Instrumentation

(AAMI), Committee on Radiation Dosimetry.

235
Division 536, Technical and Professional Committee Participation and

Leadership (cont'd.)

J. M. Robin Hutchinson

Chairman, International Committee for Radionuclide Metrology (ICRM)

Subcommittee on Low-Level Techniques.

Member, American National Standards Institute (ANSI) Committee on Nuclear Instruments and Detectors.

Secretary, ANSI Subcommittee N42.2 on Procedural Standards for

Calibration of Detectors for Radioactivity Measurements.

Kenneth G. W. Inn

Member, American Society for Testing and Materials (ASTM) Committee

C26.05 Environmental Methods Task Group on Nuclear Fuel Cycle.

Member, Methods of Radiochemical Analysis in Water and Water

Deposits, ASTM Committee D19.04.

George P. Lamaze

Secretary, American Society for Testing and Materials (ASTM),

Subcommittee E10.05, Nuclear Radiation Metrology.

Member, ASTM Committee E10, Nuclear Technology and Applications.

Robert Loevinger

Member, BIPM Consultative Committee for Standards for Measurement of

Ionizing Radiation, Section I, X- and Gamma-Rays and Electrons.

Member, Medical Internal Radiation Dose Committee, Society of Nuclear

Medicine.

Consultant, American Association of Physicists in Medicine (AAPM)

Radiation Therapy Committee.

Member, AAPM Radiation Therapy Committee Task Group 3, Regional

Calibration Laboratories.

Member, AAPM Radiation Therapy Committee Task Group 21,

Photon and Electron Dosimetry. (Disbanded August 1985)

High-Energy

Member, AAPM Radiation Therapy Committee Task Group 32,

Brachytherapy

.

Consultant, AAPM Radiation Therapy Committee Task Group 30, Total

Skin Electron Therapy.

236
Division 536, Technical and Professional Committee Participation and

Leadership (cont'd.)

Wilfrid B. Mann

Consultant, International Commission on Radiation Units and

Measurements (ICRU).

Member, ANSI-INMM Work Group INMM 8.04 on Calibration Techniques for

the Calorimetric Assay of Plutonium-Bearing Solids applied to Nuclear

Materi al s Control

.

Member, ANSI Subcommittee on Procedural Standards for Calibration of

Detectors for Radioactivity Measurements.

Honorary Council Member, National Council on Radiation Protection and

Measurements (NCRP).

Chairman, NCRP Committee 18A on Standards and Measurement of

Radioactivity for Radiological Use.

Life Member, International Committee for Radionuclide Metrology.

Emmert D. McGarry

Member, Organizing Committee for the Fifth ASTM-Euratom Symposium

Reactor Dosimetry, Geesthacht, Germany, September 1984.

Member, ASTM E10.05 Subcommittee on Nuclear Radiation Metrology.

Wi 1 1 i am L. McLaughl i

n

Chairman, International Commission on Radiation Units and

Measurements (ICRU), Committee on Absolute and Relative Dosimetry at

High Doses.

Technical Advisor, ICRU Committee on Chemical Dosimetry.

Member, American Nuclear Society (ANS), Subcommittee for Nuclear

Terminology and Units, ANS-9.

Chairman, ANS-9. 1 Subcommittee, Health Physics and Dosimetry.

Member, ASTM E10.07, Ionizing Radiation Dosimetry and Radiation

Effects on Materials and Electronic Devices.

Technical Advisor, Association for the Advancement of Medical

Instrumentation, Subcommittee on Radiation Sterilization of Medical

Devices, Task on Radiation Dosimetry.

237
Division 536, Technical and Professional Committee Participation and

Leadership (cont'd.)

William L. McLaughlin (cont'd.)

Member, ANS 9.2, Subcommittee on Shielding of the Nuclear

Termi nology

.

Technical Advisor, ISO WG-1, Nuclear Energy Terminology, Task on the

ISO TC/85, Committee on Nuclear Energy.

Technical Advisor, Council of Europe Pari i amentary Assembly, Work

Group on Aerospace Physiology, Medicine, and Radiation Measurement.

Technical Advisor, Council of Europe Pari i ament ary Assembly, Work

Group on Space Biophysics.

Member, R & D Associates Committee on Irradiated Food Products.

Member, International Atomic Energy Agency, Advisory Group on High

Dose Measurement and Standardization for Radiation Processing.

Member, Association for Advancement of Medical Instrumentation,

Working Group on Radiation Sterilization Dosimetry.

Technical Advisor, National Council on Radiation Protection and

Measurement, Scientific Committee 63, Radiation Exposure Control in a Nuclear Emergency.

Science and Technology Consultant, Committee on Interagency Radiation

Research and Policy Coordination (CIRRPC).

Member, Advisory Panel on Electron Beam Dosimetry for Industrial

Radiation Processing, International Atomic Energy Agency.

Member, Program Committee, 5th International Symposium on Radiation

Processing held in San Diego, CA, October 1984.

Member, Organizing Committee, International Workshop on Identification and Dosimetry of Irradiated Food, Federal Republic of

Germany's Office of Radiation and Environmental Health and Federal

Health Office.

Member, Industrial Panel on Status of Electron and Gamma-Ray

Dosimetry for Radiation Processing.

Robert B. Schwartz

Member, International Standards Organization (ISO) Technical

Committee 85 (Nuclear Energy) , Subcommittee 2 (Radiation Protection),

Working Group 2 (Reference Radiations).

238
Division 536, Technical and Professional Committee Participation and

Leadership (cont'd.)

Stephen M. Seltzer

Member, International Commission on Radiation Units and Measurements

(ICRU), Committee on Stopping Power.

Oren A. Wasson

Member, U.S. Department of Energy Nuclear Data Committee

Member, General Program Advisory Committee for the International

Conference on Nuclear Data for Basic and Applied Science,

May 13-17, 1985, Santa Fe, NM.

239
MAJOR CONSULTING AND ADVISORY SERVICES

Division 536, Ionizing Radiation

1. J. W. Behrens advised R. J. Howerton (CP-Di visi on) Lawrence

Livermore National Laboratory on nuclear data measurement,

systematics and evaluation on a continuing basis starting October

1984.

2. A. D. Carlson provided consultation to the U.S. Bureau of Mines on the use of neutron detectors for determining the neutron output of a neutron producing accelerator.

3. A. D. Carlson consulted with the Internati onal Atomic Energy Agency

on the development of the Monitor Reactions portion of the Nuclear

Activation Data Handbook.

4. A. D. Carlson advised North Carolina State University on nuclear

data for use in well logging experiments.

5. R. Co 11 $ advised the indoor air quality research group at the

Harvard School of Public Health on the design and preparation of a radium source for continuous radon generation.

6. R. Coll§ advised and assisted staff members in various NBS divisions

on the treatment and reporting of measurement uncertainties.

7. R. Co 116 visited radiation control program personnel in the

Wisconsin Department of Health and assisted on calibration procedures and facilities for radon measurements.

8. C. E. Dick, Dr. F. J. Sazama, Harry Diamond Lab., Silver Spring,

MD., vacuum fittings for accelerator systems.

9. C. E. Dick, Dr. Michael Moran, Lawerence Livermore Nat ' 1 . Lab.,

Livermore, CA, beam coherence in transition radiation.

10. C. E. Dick, Dr. H. Hendlowitz, Dr. Sol Glass, Howard Univ. Physics,

Wash., DC, coherence effects for Cerenkov radiation.

11. C. E. Dick, Clinton Richmond, Naval Surface Weapons Center, Silver

Spring, MD, coherence effects in Cerenkov radiation at low energies

(possible collaboration on 500 k V set).

12. C. E. Dick, Dr. Larry Fagg, Dept, of Phys., Catholic Univ. of

America, Washington, DC, calibration of electron spectrometer (magnetic deflection and Ge(Li) detector).

240
Division 536, Major Consulting and Advisory Services (cont'd.)

13. C. E. Dick, Dr. Steven Segal 1 , KMS Fusion, Ann Arbor, MI, use of Van

de Graaff accelerator for nanosecond electron beam compression.

14. C. E. Dick, Dominique Gignoux & Michael Mullendore, Data Meas.

Corp., Gaithersburg, MD, x-ray thickness gauging of composite

materi al s.

15. C. E. Dick, Jean-Charles Hardouin, Guerbet Corp., Paris, France,

measurement of the physical properties of halogenated compounds used

as radiographic contrast media.

16. C. E. Dick, M. Moran and T. Shaeffer, Lawrence Livermore Nat 1 1

.

Lab., Livermore, CA, coherent QED effects at MeV energies, i.e.

Smith-Purcell, Transition Radiation, etc.

17. C. E. Dick, Mr. Clinton Richmond, NSWL as above, measurements on 500

kV set at approximately weekly intervals. Coherence effects in

Cerenkov radiation.

18. C. E. Dick, Mr. Michael Reidinger, Tru-Lyte Systems, Inc., East

Girard, PA, accelerator usage for particle releasement for SDI.

19. S. R. Domen provided advice to the Calgary Cancer Clinic, Calgary,

Alberta, on the construction and operation of an absorbed dose water

calorimeter

.

20. S. R. Domen provided advice on construction of absorbed dose water

and polystyrene-water calorimeters, to the Massachusetts General

Hospital

.

21. S. R. Domen provided consultation and advice on absorbed dose

standards to Dr. A. Jakob of the National Office of Measures,

Budapest, at NBS during September 1985.

22. K. C. Duvall provided consultation to Consolidated Controls

Corporation, Springfield, Va. on the use of solid state detectors

for associated particle measurements within portable, sealed-tube DT generators.

23. M. Ehrlich consulted with a committee of the Health Physics Society

concerning the feasibility of establishing accredited secondary

calibration laboratories for radiation protection purposes.

24. M. Ehrlich carried out site inspections of calibration facilities at

the Idaho National Engineering Laboratory, Idaho Falls, and at Battelle Pacific Northwest Laboratories, Hanford, for the Department

of Energy Laboratory Accreditation Program (DOELAP), in November

1984.

241
Division 536, Major Consulting and Advisory Services (cont'd.)

25. M. Ehrlich provided guidance for the National Academy of Sciences

for irradiation at NBS of thermoluminescent samples from Hiroshoma

and Nagasaki

.

26. M. Ehrlich provided expert advice to the Johns Hopkins University

Radiation Dosimetry Advisory Committee, which is concerned with

personnel dosimetry for Navy shipyard workers some 25 years ago.

27. D. M. Gilliam is advising and assisting Babcock and Wilcox in preparation of high-level dosimeters for measurements in mixed gamma and

neutron radiation fields at commercial nuclear reactors. These

measurements are being made for assessing the integrity of reactor

pressure vessels and understanding radiation shielding for reducing

personnel exposure.

28. H. T. Heaton, II advised the Illinois Department of Nuclear Safety

on calibration sources and procedures for environmental thermoluminescence dosimetry.

29. J. C. Humphreys provided comprehensive experimental design plan for

testing of new polymer dosimeter for various parameters such as temperature dependence, stability of response, effects of environment and dose rate dependence. (Dr. T. Prusik, Allied Corp.

Morri stown, NJ)

.

30. J. C. Humphreys provided two days of on-site discussions and

lectures on electron beam calorimetry design and absorbed dose

measurements with radiochromic thin films (R. Christinat, Becton

Dickinson, Canaan, CT).

31. J. M. R. Hutchinson served as "Expert" to the Institute for

Radioprotection, Rio de Janiero, Brazil, to advise on the development of their low-level program.

32. K. G. W. Inn reviewed radiochemical quality control procedures at Los Alamos National Laboratory, Los Alamos, New Mexico.

33. R. Loevinger consulted with a committee of the Health Physics

Society concerning the feasibility of establishing accredited

secondary calibration laboratories for radiation protection

purposes

.

34. R. Loevinger provided consultation to the Dosimetry Section of the

International Atomic Energy Agency concerning organization and

operation of the IAEA/WHO network of Secondary Standard Dosimetry

Laborator i es

.

242
D i v i s i on 536, Major Consulting and Advisory Services (cont'd.)

35. W. L. McLaughlin, Medical Sterilization, Inc., Or. Michael Fogarty

and Dr. K. H. Morganstern. Supplied consulting services on electron

beam dose measurements in the sterilization and substerilization

range and design radiation methods for sterilization by 1 to 5 MeV

electron beams; determine effects of humidity, temperature, and dose

rate on radiochromic film response to electrons.

36. W. L. McLaughlin, Drs. Gr i 11 o and V. Deffner (Directors of

Gesellschaft fur Strahlen-und Umsweltforschung, Munich). Advised

them on national and international dosimetry standardization at high

doses with gamma radiation.

37. W. L. McLaughlin, Department of Energy, Dr. D. Ballentine. Provided

methodology for evaluating (materials testing) of polymers as a means of end-point analysis for high-dose dosimetry.

38. W. L. McLaughlin, Naval Surface Weapons Lab., Dr. M. Brown, Dr. S.

Stern. Served on panel for designing area dose monitoring in

intense charged particle beams.

39. W. L. McLaughlin, Allied Corporation, Dr. T. Prusik. Provided

thorough background material and a number of systems and analytical

tools for radiochromic dosimetry for use in food irradiation.

40. W. L. McLaughlin, Stanford Research Inst., Dr. G. Taimuty.

Consulted on new high-dose dosimetry systems for study by SRI.

41. W. L. McLaughlin, Wolf X-ray Corp., Dr. Martin Wolf. Evaluated TLD,

film badge, and solid-state detector responses as a function of x- ray photon energy.

42. W. L. McLaughlin, University of Lowell, Rad. Lab., Dr. Fred

McWilliams. Designed high-dose measurement system for standardizing

large 60 Co source dose levels (traceabi 1 ity to standards).

43. W. L. McLaughlin, Syntex Corp., Dr. Carol Lemelson. Devised proper

correction factors for erroneous dosimetry readings in radiation

sterilization applications.

44. W. L. McLaughlin, Energy Sciences, Inc., Dr. S. V. Nablo, Dr. Ken

Williams. Visit from Dr. Williams on low-energy electron beam

dosimetry and interface dosimetry.

45. W. L. McLaughlin, Isomedix, Inc., Dr. Michael Saylor. Provided

detailed instruction on the use of the new optichromic dosimeter and

radiochromic film dosimeters.

243
Division 536, Major Consulting and Advisory Services (cont'd.)

46. W. L. McLaughlin, Nepera Co., Inc., Dr. Preston Keusch. Gave

details of methods of electron beam dosimetry at very high dose

rates for industrial applications (plastic crosslinking and insulation improvement).

47. W. L. McLaughlin, Riso National Lab., Chem. Dept., Dr. B. Skytte

Jensen. Designed chemical synthesis of pure lecuo forms of radiochromic dyes.

48. W. L. McLaughlin, visit from Drs. Dennis Strickland and Donald

Rheme, HHS-NIH, advised on dosimetry and MAP for food irradiation.

49. W. L. McLaughlin, Radiation Science Dept., National Phys. Lab., Dr.

John Barrett. Provided detailed description of optimum calibration

methods for liquid-ampoule aqueous chemical dosimeters for

i ntercompari son studies.

50. W. L. McLaughlin, Radiation Sterilizers, Inc., Dr. Thomas Hurley.

Designed experiments for comparison of different types of high dose

dosimeters for use in quality control in radiation sterilization.

51. W. L. McLaughlin, Battelle NW Pacific Labs, Dr. Joseph McDonald.

Designed procedures for setting up secondary standards high-dose

calibration lab.

52. W. L. McLaughlin, Firestone, Inc., Dr. George Bohm and Dr. J Tucebrem. Suggestions of radiation effects analysis for end-point

dosimetry in the irradiation of elastomers.

53. W. L. McLaughlin, International Nutronics, Inc., Mr. Tom Rensel

.

Detailed correction factors for calculating absorbed dose in

different absorbers (Bragg-Gray corrections)

.

54. W. L. McLaughlin, J. P. Laboratories, Inc., Dr. Gordon Patel.

Assisted in development of color dose indicators for radiation

sterilization and food processing.

55. W. L. McLaughlin, Buckeye Cellulose Corp., Dr. Ralph Sellers.

Dosimetry quality assurance methods for radiation sterilization and

sterility validation protocols.

56. W. L. McLaughlin, Neutron Products, Inc., Dr. Dudley Woodard.

Gave advice on radiation chemistry of radiochromic dyes and dyed

pi astics.

57. W. L. McLaughlin, Argonne Nat. Lab., Dr. Warren McGonnagle.

Detailed discussion of pulsed beam dosimetry using liquid dye dosimeter solutions.

244
Division 536, Major Consulting and Advisory Services (cont'd.)

58. W. L. McLaughlin, General Food, Inc. Special irradiation (y-rays)

of food processing dosimeters.

59. W. L. McLaughlin, Lawrence Berkley Lab., Dr. C. A. Tobias and Dr. D. Denney. Design of special thin film dosimeters for heavy-particle

dosimetry. Radiation response of tri phenylmethane dyes.

60. W. L. McLaughlin, Becton Dickinson, Mr. Robert Christenant.

Detailed discussion of thin film dosimetry and calibration, dose

rate dependence, temperature dependence, y-rays versus electron

beams

.

61. W. L. McLaughlin, Bitek Corp, Mr. Bill Bacick. Detailed discussion

of radi ochromi c film dosimetry and sources of error for electron

beam quality control (radiation processing).

62. W. L. McLaughlin, United Technologies, Inc., Essex Group, Dr. Fred

Phillips. Instruction on the measurement of high doses and quality

control with industrial electron accelerators.

63. W. L. McLaughlin, Isotech, Inc., Dr. Gary Pageam. Described methods

of commissioning of both gamma-ray and 10-MeV LINAC radiation

processing facilities (protocols).

64. W. L. McLaughlin, Werk Pfaffikon,, Zurich, Switzerland, Dr. Hans

Widmer. Development of high-dose hydrophobic dye dosimeters for

electron beam applications in industry.

65. W. L. McLaughlin, Becton Dickinson, Dr. Richard Lasslett. Determine

response characteri sties and accuracy of a new Japanese platics

(polymethyl methacrylate) dosimeter (Radix RN- 15) for sterilization

qual ity control

.

66. W. L. McLaughlin, Insul-Tab, Inc., Dr. Clement Bourgault. Determine

response characteristics of a dyed cellulose triacetate film dosimeter for very high doses of low energy electron beams.

67. W. L. McLaughlin, Kleer-View Index, Inc., Dr. John Wos. Determine

response characteri sties of a dyed polyvi nylchloride film dosimeter

for moderately high doses of low-energy electron beams, including

optimization of post-irradi ation heat treatment.

68. W. L. McLaughlin, American Converters, American Hospital, Supply

Corp., Dr. H. Schaffer, Ruth Garcia. Designed commissioning

dosimetry protocol and standard procedures for administrating highdoses of gamma-rays to large volumes of surgical supplies.

245
Division 536, Major Consulting and Advisory Services (cont'd.)

69. W. L. McLaughlin, Champlain Cable Corp, Dr. Richard Waldron.

Supplied new techniques of film dosimeters to replace blue

cellophane as a dosimeter for industrial electron-beam applications.

70. W. L. McLaughlin, Food and Drug Admin., Dr. Leonard Nessen.

Provided measurement quality assurance procedures for the radiation

sterilization of medical devices.

71. W. L. McLaughlin, Escuela Politecnica Nacional, Equador, Dr. Trajano

Kamires. Provided calibrated dosimeters in collaboration with

Industrial and Dosimetry Section (Dr. V. M. Markovic) of

International Atomic Energy Agency, Vienna, Asutria.

72. W. L. McLaughlin, Atomic Energy of Canada, Ltd., Dr. Michael

Antoni ades. Measurement assurance methods for gamma-ray industrial

applications.

73. W. L. McLaughlin, Department of Commerce, Office of Reg. and Federal

Programs Analysis, Dr. Phillip Lewis. 1984-1985 new development in

1 arge radiation source technology (gamma rays, x-rays, and electron

beams) for industrial applications.

74. W. L. McLaughlin, Southwest Research, Inc., Mr. David Cadena, Jr.

Methods of standardizing the high-dose response of solid-state

dosimeters (alkali halide crystals) against their thermol umi nenes- cence response characteri sties

.

75. W. L. McLaughlin, Kimball, Inc., Dr. Nancy Trewin. Methods of

standardizing radiochromic film dosimeters for sterilization by

ionizing radiation.

76. W. L. McLaughlin, Conservatome, France, Dr. B. Dove. Advised on the

available methods of standardi zi ng red Perspex dosimeters for radiation sterilization applications.

77. W. L. McLaughlin, Association for Dressings and Sauces, Dr. Jane

McDonald. Conducted tour of CRR and lecture to members of

Assocation on dosimetry for food irradiation.

78. W. L. McLaughlin, IRT Corp., Dr. Elaine Bondos. Supplied rate

dependence data for radiochromic film dosimeter response to electron

beams, for applications in doping semi-conductors and lithography

with LINAC radiation sources.

79. W. L. McLaughlin, Harvard Med. School, Dept, of Radiology, Dr. Goran

Svensson. Mapping of radiation doses in cancer patients being

treated by high energy charged particle beams (protons).

246
Division 536, Major Consulting and Advisory Services (cont'd.)

80. W. L. McLaughlin, Univ. of Nebraska, Dept, of Physics, Dr. M. P. R.

Waligorski. Developed tissue equivalent dosimeters for high-LET

radiations (heavy charged particles and neutrons).

81. W. L. McLaughlin, UK National Rad. Protection Board, Dr. J. C. Dutt.

Provide guidelines for standardization of high-dose measurement of

electron and gamma-ray dosimetry for industrial applications.

82. W. L. McLaughlin, Abbott Laboratories, Mr. Carlos Parra.

Description and protocol for use of dye dosimeters for standardizing

radiation sterilization by large 60 Co gamma-ray sources.

83. W. L. McLaughlin, IMED Corp., Dr. Edward F. Waddell. Devised

improved dosimetry methods for accurate determination of comparative

responses of various microbe populations to gamma rays and electron

beams in radiation sterilization.

84. W. L. McLaughlin, Assistance Industrelle Dauphinoise, France, Dr. P.

Marion. Designed techniques for use of very thin radiochromic films

to measure dose distribution interfaces of materials irradiated by

electrons.

85. W. L. McLaughlin, CERN, Geneva, Switzerland, Dr. H. Schonbacher.

Designed a color film (radiochromic) visual monitor for long-term

radiation damage detection in magnets in large ring charged particle

beam lines.

86. W. L. McLaughlin, IRT Corp., Dr. Andrew Weiman. Assisted in formulating methods for calibrating thin film dosimeter response in silicon to gamma rays and electron beams at high fluence rates.

87. W. L. McLaughlin, Design Magnetics Corp., Dr. Mark Smith. Design an experiment and test method with thin-film dosimeters for improving

accuracy and quality control in the radiation processing of magnetic

tape, using 100-300 keV electron beams. Attend meetings on food

irradiation policy and technology issues.

88. W. L. McLaughlin, Baxter-Travenol , Dr. Monte Wisler. Provided

response data for new Japanese clear plastic, (polymethylmethacrylate) dosimeter (Radix RN-15)

.

89. W. L. McLaughlin, NASA-Goddard and Hampden-Sydney College. (Prof.

Thomas Joiner). High-dose dosimetry procedure design for semiconductor device arrays (very high doses).

247
Division 536, Major Consulting and Advisory Services (cont'd.)

90. W. L. McLaughlin, Argatom, Dr. Riccardo Bustamante, Dr. Raul Fitte,

President. Provided details of gamma-ray irradiator design and

dosimetry for industrial applications, radiation testing, and

processi ng.

91. W. L. McLaughlin, Synchron Corp, Dr. John Harris. Develop quality

control methods for uniform irradiation and monitoring for the

sterilization and large quantities of human blood (quantities in

tons)

.

92. W. L. McLaughlin, Abbott Laboratories, Dr. M. Capp, Carl Bods.

Provided descriptions and correction factors of ceric-cerous aqueous

chemical dosimetry systems.

93. W. L. McLaughlin, Food Irradiation Research Committee, Dr. J. M.

Wagland. Provided detailed food irradiation dosimetry data for

quality control in the irradiation of various food types.

94. W. L. McLaughlin, Radiation Technology, Inc., Dr. M. S. Fidan.

Supplied patent information and radiation chemical anaylsis methods

for stereospecific polymers, including particularly polyethylene,

polystyrene, and polypropyl ene.

95. W. L. McLaughlin, California Dept, of Food and Agriculture, Dr.

Joseph Rothleder. Supplied details of fiber optics dosimetry for

quality control and standardization of food irradiation.

96. W. L. McLaughlin, Kernonturkkel ingskorporasie, South Africa, Dr.

Hendrik vander Linde. All day visit to learn about MAP procedures

for standardizing high dose dosimetry for industrial applications.

97. W. L. McLaughlin, Chinese Delegation visits. Dr. Xie, Dr. Lin,

Director Public Health, Beijing. Radiation measurement standardization for medical and health applications.

98. W. L. McLaughlin, Bisco, Dr. James Anderson. Devised methods of

standard irradiation of polymer-metal composite materials to very

high doses of gamma rays.

99. W. L. McLaughlin, St o 1 1 e Corp, Dr. B. Johnson. Designed method to

test temperature dependence and reproducibi 1 ity of response of

biological indicators (bacillus pumilus) to gamma radiation.

100.

W. L. McLaughlin, Radiation Dynamics, Inc., Dr. Marion Strelcyk.

Supplied correction data for converting electron beam energy

depositer data to correct depth-dose data in totally absorbing

calorimeters

.

248
Division 536, Major Consulting and Advisory Services (cont'd.)

101. W. L. McLaughlin, U.S. Dept, of Agriculture, Policy Branch. Dr.

Rosanna Morrision. Supplied qua! tiy-control data in terms of

standardized dosimetry results, in a typical food irradiation

process.

102. W. L. McLaughlin, Kiolgray, Inc., Dr. Michael Yang, Dr. Walter

Chappas. Solved Bragg-Gray problem in the irradiation of semiconductor chips for IBM Corp. when held between metal interfaces.

103. W. L. McLaughlin, North American Science Associates, Dr. Scott K.

Smith. Designed calibration method for the accurate irradiation of

thin micro biological spore strips.

104. W. L. McLaughlin, Michigan Tissue Bank, Dr. Jim Forsell. Design

methods for Bragg-Gray cavity theory corrections in the dosimetry

for radiation sterilization of various prosthetic devices.

105. W. L. McLaughlin, Atomic Energy of Canada, Ltd., Dr. D. K. Mehta.

Design special test and calibration methods for metallic materials

irradiations to very high doses of gamma rays.

106. W. L. McLaughlin, NASA, Ames, CA, Dr. J. Goldenrath. Devised method

for monitoring halogenated fluids inside pipes near high-dose

neutron fields, by liquid chemical dosimetry techniques.

107. W. L. McLaughlin, Rockwell Int., Dr. Brian Oliver. Gave instruction

on the use and potential sources of uncertainty in the use of

aqueous chemcial dosimeters (e.g. ferrous sulfate, ceric sulfate,

etc

.

108. W. L. McLaughlin, Nat. Inst, for Pub. Health and Env. Hygiene, Dr.

A. M. L. Albers. Design methods for calibration of lyol umi nescence

dosimeters and temperature dependence studies.

109. W. L. McLaughlin, St. Bartholomew Hospital, Dr. David R. White.

Design of bone-equivalent plastic dosimeters for high-dose ranges

radiation therapy with photons and electrons.

110. J. S. Pruitt visited the Idaho National Engineering Laboratory,

Idaho Falls, to advise on calibration of beta-particle sources, and

to provide two such calibrations.

111. R. B. Schwartz consulted with the Battelle Pacific Northwest

Laboratory on measurement traceability to NBS of the Department of

Energy Laboratories Accreditation Program for Personnel Dosimetry.

249
Division 536, Major Consulting and Advisory Services (cont'd.)

112. R. B. Schwartz consulted with Argonne National Laboratory on establishing and maintaining traceability to NBS of neutron

measurements carried out at Argonne in connection with their NRC

contract for checking the accuracy of instruments used by NRC

1 icensees

.

113. R. B. Schwartz consulted and advised Los Alamos National Laboratory

on the development of a new type of remmeter.

114. J. T. Weaver carried out a site inspection of calibration facilities

of Battel le Pacific Northwest Laboratories, Hanford, for the

Department of Energy Laboratory Accreditation Program (DOELAP), in

November 1984.

250
JOURNAL EDITORSHIPS

Division 536, Ionizing Radiation

B. M. Coursey, Editor, International Journal of Applied Radiation and

Isotopes.

W. B. Mann, Editor, Environment International.

W. B. Mann, Editor, International Journal of Nuclear Medicine and

Biology.

W. B. Mann, Editor-in-Chief for North America, International Journal of

Applied Radiation and Isotopes.

W. L. McLaughlin, Editor, International Journal of Applied Radiation and

Isotopes.

W. L. McLaughlin, Editoral Board, Radiation Physics and Chemistry.

M. G. Simic, International Editorial Board, Free Radicals in Biology and

Medicine.

251
TRIPS SPONSORED BY OTHERS

Division 536, Ionizing Radiation

J. W. Behrens spent a year as a guest scientist with the Commi ssari art a l'Energie Atomique Centre d

1 Etudes Bruyeres-le-Chatel , France. (January - December 1984)

.

M. J. Berger, sponsored by the International Atomic Energy Agency traveled

to Rijswijk, the Netherlands to participate in an Advisory Group Meeting

on Nuclear and Atomic Data for Radiotherapy and Related Radiobiology.

(September 16-20, 1985)

J. M. Calhoun attended the 1985 Society of Nuclear Medicine Conference and

Exhibit in Houston, Texas. (June 1985)

A. D. Carlson, sponsored by the International Atomic Energy Agency (IAEA),

traveled to Geel , Belgium to present an invited paper and chair a session

at the IAEA Advisory Group Meeting on Nuclear Standard Reference Data.

(November 12-16, 1984)

A. D. Carlson, sponsored by the IAEA, traveled to the Nuclear Energy

Agency, near Paris, France to discuss collaboration between European and

IJ.S. scientists in the formation of Nuclear Data Files. (November 19,

1984)

R. S. Caswell, sponsored by Columbia University, traveled to Irvington,

N. Y. to attend meeting of the Scientific Advisory Committee to the

Radiological Research Accelerator Facility (RARAF). (December 17, 1984)

R. S. Caswell, sponsored by the International Commission on Radiation

Units and Measurements (ICRU), traveled to Harwell, England to attend

annual meeting. (June 1-9, 1985)

J. J. Coyne, sponsored by the International Atomic Energy Agency, traveled

to Rijswijk, the Netherlands to participate in an Advisory Group Meeting

on Nuclear and Atomic Data for Radiotherapy and Related Radiobiology and

present an invited paper on Secondary Charged Particle Spectra and Kerma

Calculations. (September 16-20, 1985)

J. H. Hubbell, sponsored by the Laboratorio de Metrologia dell Radiazioni

IonizzantS, traveled to Ferrara and Frascati, Italy to participate as Committee Secretary at a meeting of the Internati onal Programme Committee

for the Third International Symposium on Radiation Physics, and following

that meeting gave an invited seminar in Casaccia, Italy. (September 30 - October 23, 1984)

252
Division 536, Trips Sponsored by Others (cont'd.)

J. C. Humphreys, sponsored by the FMC Corporation, traveled to and gave

talk, "Industrial Radiation Technology", at the FMC Corporation, Santa

Clara, CA. (September 26, 1985)

J. M. R. Hutchinson, IAEA sponsored consultation to Comissao Nacional de

Energia Nuclear (CNEN), Rio de Janiero, Brazil. (September 1985)

R. Loevinger participated in meetings of the MIRD Committee of the Society

of Nuclear Medicine in Las Vegas, Nevada. (December 6-7, 1984)

R. Loevinger participated in meetings of the MIRD Committee of the Society

of Nuclear Medicine in San Francisco, California. (July 11-12, 1985)

W. L. McLaughlin, sponsored by the IAEA, attended seminar and gave talk,

"Fiber Optics Dosimetry", at the Ristf National Laboratory, Denmark.

(October 4, 1984)

W. L. McLaughlin, sponsored by Battel le, NW, gave talk, "Dosimetry for

Applied Radiation Technologies", at seminar for the Radiological Sciences

Dept., Battelle NW, Richland, WA. (November 1, 1984)

W. L. McLaughlin, sponsored by the ICRU, attended the annual meeting of

International Commission on Radiation Measurements and Units, Harwell,

England. (June 1985)

W. L. McLaughlin, sponsored by the U.S.-Yugosl av Joint Board on Scientific

and Technical Cooperation, attended the Seminar on Scientifc Cooperation

between NBS and IBK in the 1980-1984 period, Belgrade Yugoslavia. (June

10-11, 1985)

W. L. McLaughlin, sponsored by the U .S. -Yugosl av Joint Board on Scientific

and Technical Cooperation, gave talk, "Radiation Dosimetry with

Radiochromic Dyes", at the NBS-Boris Kidric Institute Seminar, Boris

Kidric Inst, of Nuclear Science, Vinca, Belgrade, Yugoslavia. (June 11,

1985)

W. L. McLaughlin, sponsored by the FDA, gave training course on Validation

Procedures and Dosimetry in Routine Industrial Radiation Sterilization at

the Ramada Inn, Culver City, CA. (June 26, 1985)

W. L. McLaughlin, sponsored by the FMC Corporation, traveled to and gave

talk, "Industrial Radiation Technology", at the FMC Corporation, Santa

Clara, CA. (September 26, 1985)

R. B. Schwartz, sponsored by the International Atomic Energy Agency,

traveled to Vienna, Austria to finish writing handbook for setting up

secondard standard dosimetry 1 aboratori es. (November 5-10, 1984)

253
Division 536, Trips Sponsored by Others (cont'd.)

R. B. Schwartz, sponsored by the Department of Energy, traveled to

Richland, Washington, to advise on making their dosimetry calibration

program traceable to NBS. (November 28-30, 1984)

M. G. Simic, sponsored by the Food Processor Institute, gave talk,

"Dosimetry of dosage received. Irradiated Foods: A New Business", at the

Food Processor Institute, San Francisco, CA. (February 15, 1984)

M. G. Simic, sponsored by Nabisco, gave talk "Fat Oxidation and Antioxidants", at the Nabisco Brands Lipid Symposium, Nabisco, Rochelle Park, NJ.

(November 15-16, 1984)

M. G. Simic, sponsored by the American Chemical Society, gave talk, "Antioxidants, Kinetics and Mechanisms," at the Lipid Oxidation Symposium,

Miami Beach, FL. (April 28-May 3, 1985)

M. G. Simic and M. Al-Shiekhly, gave talk "Superoxide Radical Generation

in Radiation-Induced Autoxidation of Fatty Acids, at the 4th Int. Conf. on "Superoxide and Superoxide Dismutase", Rome, Italy (September 1-6,

1985)

254
STANDARD REFERENCE MATERIALS

Division 536, Ionizing Radiation

Standards Issued - 1 August 1984 through 31 July 1985

SRM Radionucl i de Principal Use

4417L-D Indium-111 Calibration of instruments

for activity measurements

of radiopharmaceuticals

4410H-J Technet i um-99m ll

4406L-H Phosphorus-32 II

4420L-B Lead-203 ll

4401L-K Iodi ne-131 ll

4412L-J Molybdenum-99 ll

4415L-I Xenon-133 ll

4416L-F Gal 1 i um-67 ll

4404L-H Thai 1 i um-201 ll

4400L-6 Chromi um-51 II

4927C Hydrogen-3 solution Calibration of liquid

scintillation counters

4214B

4408L

Cobalt-57 point source Cobalt-57 solution

Calibration of gamma-ray

detectors

4929D Iron-55 solution For use in calibrating

instruments for measurement

of this nuclide in the

nuclear fuel cycle

4226B Nickel-63 solution ll

4276B Mixed Radionuclide solution

antimony-125, europium-154

and europium 155

Gamma ray standard used for

the efficieny calibration of

x- and y-ray of detectors

255
Division 536, Standard Reference Materials (cont'd.)

SRM Radi onucl ide Principal Use

4950E Radium-226 solution Calibration of detectors

4953D Radium-226 solution used for monitoring this

nuclide and radon in the

environment

Used as a chemical yield

monitor for radiochemical

measurements of nuclides

in the nuclear fuel cycle

II

4329 Curium-243 solution "

4327 Polonium-208 solution

4328 Thorium-229 solution

256
CALIBRATION SERVICES PERFORMED

Division 536, Ionizing Radiation

I. Neutron Dosimetry Group

No. of Income

Type of Service Customer SP 250 Tests k$

Neutron Source Amersham 8. IB 1 1.70

Cal i brations Battel le Northwest 8. 1C 1 1.68

Argonne Labs 8. 1C 1 1.68

Lawrence Livermore Spec 8. IB 1 1.50

Scandia Labs 8. IB 1 1.68

Total 5 8.24

Thermal Neutron

Density Standards

(No calibrations) 0 0.00

Total 0 0.00

Neutron Personnel Calvert Cliffs 8.1J 23 5.0

Protection U . S . Army 8.1H 1 .25

Instruments & U . S . Army 8.1J 1 .25

Filtered Beams Omaha Public Power 8.1J 3 .75

Carolina P&L 8.1J 1 .25

Northwestern Univ. 8.1J 1 .25

NRC 8.1J 2 .40

Eberline Instr. Corp. 8.1H 3 .50

Barlett Nuclear Corp. 8.1J 4 .80

WPPSS 8.1J 2 .40

Illinois Power 8.1J 2 .40

Eberline Instr. Corp. 8.1J 2 .50

NSWC 8.1J 6 .80

Lawrence Livermore Lab 8.1H 1 .25

Total 52 10.80

257
Division 536, Calibration Services Performed (cont'd.)

II. Radioactivity Group

August 1, 1984 to August 1, 1985

Scheduled

Calibrations^

)

Non-scheduled Tests

Number Total Number Total

of Fee of Fee

Sources $K Sources $K

Category

Alpha-Particle Sources

8.2 H, I, J 34 25.7 3 2.3

Beta-Particle Point Sources

and Gases ( 85 Kr)

8.2 P, Q, R

- - — 16 7.8

Gamma-ray Solutions, Point

Sources, and Gases ( 133 Xe)

7 7.0 43 30.9

Mixed Radionuclide Sources,

Solutions, Point Sources

and Gases( 2

)

— - “ 18 22.0

Other Services — — — 3.9

41 32.7 80 66.9

Footnotes

(1) Multiple sources under one Test Folder are counted as multiple

calibrations. Replicate samples are not considered as separate sources.

For example, Amersham submits 2 each of 3 different source forms. This is

counted as 3 samples.

258
Division 536, Calibration Services Performed (cont'd.)

III. Radiation Chemistry & Chemical Dosimetry Group and

Electron & Photon Dosimetry Group

Type of Service

Customer

Type*

SP 250

Item No.

Number of

Cal ib 'ns or Tests Income

Cal ibration of x-ray

and y-ray measuring

i nstruments

1-7 8.3A.B.C,

D 240 )

)

)

)

)

)

$ 140k

Irradiation of TL

dosimeters

2-6 8.3M,N 110

Cal i bration of y-ray

and 6-particle sources 2-6 8.4A,E,K 45 $ 6k

Chemical dosimetry mea- surement assurance service for electron beam

2 8 . 5A, B ,C 125 $ 22

High-dose irradiation 3-7 8.6A,B 565 )

)

)

)

)

Dose interpretation 4-7 8.6C 110 $ 75k

Spectrophot. reading

of dosimeters

4-6 8.6D 470

Irradiat. of TLDs

& prep, of units for

shipboard measurement

Navy N.A. 275 $ 65k

Instrument calibration

& evaluation

DoE N . A. 6 S 9k

Total s 1940 $320k

*Column 2: 1, calibration labs; 2, hospitals; 3, nuclear energy establishments; 4, industry; 5, US government labs; 6, DoD labs; 7, universities.

259
SPONSORED SEMINARS AND COLLOQUIA

Division 536, Ionizing Radiation

H. Lesiecki, Physi kal i sch-Techni sche Bundesanstalt, "Neutron Fields and

Neutron Calibrations at PTB", October 23, 1984.

Christian Ballaux, SCK/CEN, Mol, Belgium, "An Overview of Reactor and

Waste-Disposal Programs at the Belgian Center for Nuclear Energy, with

Some Details of the Radionuclide Metrology Involved", October 25, 1984.

Lennart Lindborg, National Institute of Radiation Protection, Stockholm,

Sweden, "Variance-Covariance Measurements. A Technique for Microdosimetry

in High-Energy Beams", November 8, 1984.

Richard Sah, Accelerator and Fission Research Division, Lawrence Berkeley

Laboratory, "The Design Study for the Advanced Light Source", December 13,

1984.

David Van Holstein and Laurel 0. Sillerud, "The Role of Standards in

Nuclear Magnetic Resonance (NMR) Imaging", January 31, 1985.

Geoffrey Greene, Quantum Metrology Group, Center for Basic Standards, NBS,

"Cold Neutron and Hot Physics: Investigating Fundamental Physics with Low

Energy Neutrons", February 28, 1985.

P. J. Matthew, CSIRO, Division of Mineral Physics, Port Melbourne,

Australia, "Recent Developments in the Application of Nuclear Techniques

in the Mineral Industry in Australia", April 1, 1985.

James W. Behrens, Center for Radiation Research, NBS, "Applied Neutron

Physics Projects in France", April 4, 1985.

Horst Klein, Physi kal i sch-Techni sche Bundesanstalt, Braunschweig, West

Germany, "Neutron Cross Section Measurements at PTB", May 23, 1985.

D. A. Bradley, School of Physics, University of Science of Malaysia,

Minden, Penang, Malaysia, "Recent Measurements of Coherent Scattering",

May 24, 1985.

J. Trochon, CEA-DAM, Bruyeres- 1 e-Chatel , France, "Cold Fragmentation

Measurements using a Very-Hi gh-Energy Resolution Ionization Chamber", June

6, 1985.

Albert Lajtai, Central Research Institute for Physics, Hungarian Academy

of Sciences, Hungary, "Measurements of Fission Neutron Spectra", June 10,

1985.

260
TECHNICAL ACTIVITIES

Division 530.01 Nuclear Physics

Task No. 15222 - Nuclear Structure and Standards

Task No. 15223 - Nuclear Radiation Research

The Nuclear Physics Group conducts fundamental research in

theoretical nuclear and particle physics, and in experimental studies of

intermediate energy electro- and photo-nuclear reactions. This activity

is in support of the Center's role in carrying out research necessary for

improved understanding of nuclear radiation processes and of the interaction of radiation and particles with matter. This year the formerly

separate Nuclear Theory Group (M. Danos, L. C. Maximon, and S. Meshkov)

and Nuclear Research Group (experimentalists: W. R. Dodge, E. Hayward,

J. W. Lightbody, Jr., and X. K. Maruyama; theorist: J. S. O'Connell) were

combined to form the Nuclear Physics Group. There has always been strong

overlap of interests and mutual support between the two groups, which has

proven beneficial to both. We expect the reorganization will strengthen

this tradition and therby enhance the overall nuclear physics program.

There has been no change in emphasis of the separate, experimental and

theoretical research activities.

A vital research program is one that addresses priority questions in

nuclear theory and experiment and, therefore, requires forefront facilities and a constant exchange of ideas and strong interplay with other

laboratories and researchers in the field. The Nuclear Physics Group is

planning electro-nuclear coincidence experiments that have been made

feasible by the 200 MeV cw racetrack microtron (RTM) now under development

at NBS, which will complement the 20 year old 120 MeV electron linac.

Nuclear experiments with the linac are being phased out although neutron

measurements will continue with this machine. In addition, the group is

participating in forefront electro-and photo-nuclear experiments at the

higher energy accelerators (MIT and Mainz), and is involved in planning

the next generation electron accelerator (CEBAF), aimed at exploring the

QCD/nuclear physics interface. The NBS research program profits greatly

from the participation of guest workers and collaborators (university

faculty and graduate students), who extend our resources and bring in new

ideas. We encourage these involvements and, additionally, have an extensive seminar program which brings outside speakers to NBS.

This year many visitors and guest workers contributed to our programs. The list of scientific colleagues who have had extensive visits to

NBS include: Miles McCord, Hall Crannell , Dan Sober, Larry Fagg, The

Catholic University of America; James O'Brien, Montgomery College; Paul

Treado, Georgetown University; Philippe Gouffon, University of Sao Paulo,

261
Nuclear Physics, Technical Activities (cont'd.)

Brazil; Johann Rafelski, University of Cape Town, South Africa; Hartmuth

Arenhovel , University of Mainz, Mainz, West Germany; M. Sanzone,

University of Genoa, Italy; William Briscoe and Francisco Prats, George

Washington University; and Bent Schr0der, University of Lund, Sweden.

In addition to guest worker scientists visiting NBS, some members of

the Nuclear Physics Group have had extended stays at other nuclear

laboratories: L. Maximon and M. Danos, Centre d'Etudes Nucl$aire de

Saclay, France; E. Hayward, Oxford University Nuclear Physics Laboratory

(England); S. Meshkov, Aspen Center for Physics (Aspen, CO) and the

Institute for Theoretical Physics (University of Cal i forni a-Santa

Barbara); X. K. Maruyama, Naval Postgraduate School (Monterey, CA); and

J. S. O'Connell, Lewes Center for Physics (Lewes, DE). These visits

provide valuable new insights to our current research and often provide

the perspective to plan and direct our future research activities.

In the following sections we outline the groups primary research

activities of the past year. This list includes: elementary particle

physics, nuclear theory, electromagnetic nuclear physic theory, current

experimental activities at NBS and other laboratories, proposals for OA

funding of research facilities, and miscellaneous activities.

Elementary Particle Theory . The elementary particle theory program

under Dr. S. Meshkov has activities on many fronts. Work on the possible

existence of fermions in addition to those of the "standard model," whose

gauge group SU3 x SU~ x U| is broken at low energies to SU3 x uj, was actively pursued. This resulted in two publications in Physical Review j),

which showed that without violating low energy bounds given by the u

->• ey

decay rate, significant effects in the decay of the W and Z vector bosons

to neutral, left-right symmetric neutral singlets could occur via mixing

with the standard model neutrinos. This work was also discussed at numerous seminars at major laboratories.

Work on QCD took a new turn. In addition to a continuation of work

on glueballs, Meshkov and collaborators showed that when a recent Monte

Carlo Lattice Gauge QCD Potential was confronted with experimental bb and

cc quarkonia data, it gave results which, though qualitatively suggestive,

were not quantitatively correct. This work, described in a paper submitted to Physics Letters _B, led to a more general study of quarkonia in

which it was shown by Fishbane, Kaus, and Meshkov that for a separation

r > R

c

, all heavy qq systems can be quantitatively described by a potential characteri Stic of strings, in particular the Nambu-Gotow string.

This work is being continued at the Institute for Theoretical Physics

Workshop on Nuclear Chromodynamics at the University of California at

Santa Barbara to which Dr. Meshkov was invited and is a participant.

262
Nuclear Physics, Technical Activities (cont'd.)

Nuclear Theory . The activities described in this section were carried out by Dr. M. Danos and co-workers. In the past, nuclear forces

have been treated by computing a nucleon-nucleon 2-body force in terms of

meson exchanges between point nucleons treated in second order perturbation, although it was realized that these nucleons were not point

particles but in fact occupied a large part of the volume of nuclei. Now

the origin of nuclear forces must be rethought in terms of the underlying

quark structure. There are two aspects to this problem. First, the

"short-range part" of the interaction must be re-done in terms of explicit

quark degrees of freedom. The model available for this treatment is the

bag model. However, two-nucleon interactions in this model have six

quarks in the bag, and if an exchanged meson is included then there are seven quarks and an antiquark. There are many-body correlations among the

quarks. A program to investigate these forces has been started.

To replace the ad hoc boundary conditions of the bag model by a correct description of the hadron-vacuum interface in fact requires a solution, or at least a semi -quantitative understanding, of the confinement problem. It is widely believed that the confinement in QCD, in

analogy with superconductivity, results from the existence of a physical

vacuum which is removed from the remainder of the spectrum by an energy

density gap, which exhibits a Mei ssner-Ochsenfel d effect, and which can not be described by the methods of perturbative quantum field theory.

More parti cul arly , it is believed that these characteri sti cs of the

physical vacuum result from the infrared properties of QCD. Utilizing

these considerations an attempt is underway to construct a model of the

QCD vacuum with the techniques developed in the context of superconductivity theory.

The other aspect concerns the "long-range part" of the interaction,

i.e., that part where the microscopic structure of the vertex is unimportant. There the many-body aspects of the system nucleus + mesons have to

be accounted for, which are neglected in the presently employed perturbation treatment of the nuclear force. This proper description requires

that the nucleus be treated as a relativistic many-body system. A program

of such a treatment is underway.

A new emerging field of nuclear physics concerns the question of ex- plicit manifestations of QCD effects in nuclear reactions. A promising

approach is the observation of a quark-gluon plasma in the collision of

two heavy nuclei. Diverse aspects of this are being explored.

An example of the importance of quarks in the nucleus is a recent

study in which experiments at Stanford and by the European muon collaboration have been used to show that between 2 and 10 percent of the quark

wave functions occupy the nucleus as a whole rather than are correlated

into individual nucleons.

263
Nuclear Physics, Technical Activities (cont'd.)

A different approach to correlations in the nucleus has been the

recent study of the Crystalline Nucleus. The nucleus is modelled as a cubic crystal with alpha particles at each lattice point. One alpha

particle is excited to its 1" state and the transmission of this excitation through the crystal lattice is studied. A good fit to the Giant

Dipole Resonance for integer values of A/4 is obtained. There are only

two parameters in the theory. The one is the excitation energy of the

1” state of the a particle inside a nucleus and the other is the offdiagonal matrix element for the interaction between nearest neighbors.

The good fit is obtained with reasonable values for these parameters.

Electromagnetic Nuclear Physics Theory . The activities in this area

are carried out by Drs. L. C. Maximon and J. S. O'Connell. High energy

electron scattering and photonuclear reactions continue to be one of the

most important probes of nuclei. Sub-nuclear degrees of freedom —

involving nucleon resonances, mesons, and quarks — are currently in the

forefront of electromagnetic nuclear physics, on a world-wide scale, with

major facility expansions to address the new physics questions planned or

in the construction phase. In addition to the 200 MeV cw electron

accelerator (RTM) under construction at NBS, the MIT pulsed linac is being

upgraded to near 1 GeV and there are plans to provide a stretcher ring to

convert the pulsed beam to a cw beam. Finally, in this country there is a major DoE project to construct a 4 GeV cw electron facility (CEBAF) in

Newport News, VA.

Because of the different types of experiments planned and because of

the extended range of energies that will become available, theoretical

expressions for the radiation processes will have to be reinvestigated.

This includes study of bremsstrahl ung processes, bremsstrahl ung polarization, radiation tails in electron scattering, and radiative corrections to

electron coincidence reactions. Dr. Maximon is preparing an article for

Physics Reports on “Tagged Photons; An Analysis of the Bremsstrahl ung

Cross Section." He is also preparing an article for Physical Review on "Angular Distribution of High Energy Electrons Following Radiation" with

A. LePretre.

In addition. Dr. Maximon is working with Professor F. Prats of the

Nuclear Theory Group at George Washington, on the photodisintegration of

few-body systems. This collaboration is an extended activity and has in

the past dealt with pionic disintegration of few-body systems as well.

Dr. O'Connell has written a review article with J. Ahrens of Mainz

summarizing photon and electron interactions in the delta region (200-

600 MeV excitation in nuclei). They discuss the remarkable discovery that

all nuclei examined display the same response per nucleon to photon

absorption and a universal response to electron scattering in the delta

region. The medium modification of the fundamental electromagnetic pion

production mechanism from a free nucleon seems to be characteristic of

nuclear matter.

264
Nuclear Physics, Technical Activities (cont'd.)

Neutrino reactions on nuclei can be calculated in the same framework

as electron scattering reactions. Dr. O'Connell has updated an earlier

calculation he has done, to try and understand the electron and muon events observed in deep underground water Cerenkov detectors which are used in searches for spontaneous proton decay. The introduction of

nucleon binding and treatment of Pauli blocking effects for oxygen led to

agreement between the predicted and observed lepton spectra generated by

cosmic ray neutrinos. This work was done in collaboration with T. Gaiser

of the Bartol Research Foundation.

Finally, in connection with the CEBAF project. Dr. O'Connell has

calculated a number of reaction cross sections and coincidence experiment

counting rates for GeV electrons on complex nuclei. This effort is part

of a study (involving many people in this country and around the world)

leading to the design of magnetic spectrometers at the proposed CEBAF

accelerator.

Experimental Nuclear Physics . Activities in this area are carried

out by Drs. W. R. Dodge, E. Hayward, J. W. Lightbody, Jr., X. K. Maruyama,

and J. S. O'Connell. There are two experiments which were recently

completed at the linac. Electron scattering measurements (Lightbody,

Maruyama, and collaborators) for the proton were performed to extract the

root mean square charge radius. The analysis of these data, which are the

Ph.D. thesis data of M. McCord of CUA, is in progress. The old proton

radius value of 0.80(1) fm is in substantial disagreement with the newer

Mainz result of 0.86(1) fm. Our goal is to provide further data to help

resolve this issue. The major interest in this subject comes from the

field of Lamb shift measurements, where recent work indicates that the

agreement with current QED calculations would be improved a great deal

with the older 0.80 fm proton radius.

An electrodistintegration experiment on 24 Mg has also been completed

recently by Dr. W. R. Dodge. This work was in collaboration with members

of the Physics Institute of the University of Sao Paulo, and is the

Ph.D. thesis subject for P. Gouffon., This (e,x) experiment examines the

alpha decay of a 2 + level in 24 Mg to the ground state of 20 Ne. The

results are being analyzed and should constitute the first assumption free

test of E2 virtual photon theory.

Together with members of an NBS-LUND-UNH-MIT collaboration we initiated a series of coincidence measurements of the 238 U(e,e'f) cross section at electron energies extending through the quasi-free scattering

and delta region (W. R. Dodge, E. Hayward, J. W. Lightbody, Jr.,

X. K. Maruyama, and J. S. O'Connell). This work was done at the MIT/Bates

Linear Accelerator. The experiment measures the time coincidence of the

fission process with electron scattering. The fission process coincidence

requirement eliminates unwanted radiation processes which encumber the

265
Nuclear Physics, Technical Activities (cont'd.)

single arm (e,e') measurements in this energy-loss region and shows

interesting new features of the fission and nucleon knockout process.

Preliminary results in the delta region show that uranium exhibits the same universal absorption curve as seen in the lighter nuclei (A < 16).

In addition to the fission experiment, a 180° (e ,e

1 ) measurement was performed at Bates (Lightbody and Flanz of MIT). This is the only laboratory in the U.S. with such a 180° scattering capability. The measuremnts

were made at low monmentum transfer on the 2* state of 52 Cr to investigate

the role of convection currents in nuclear excitations.

The Nuclear Physics group is also involved in other on-going experiments at Bates. The most important of these is the tritium (e,e‘)

measurement scheduled for fall 1985. This represents a major commitment

of time by Dodge, Lightbody, and Maruyama. This experiment will demonstrate our fundamental understanding of the three-body system in a region

where we expect serious modifications of potential models by non-nucleonic

degrees of freedom. This experiment is the highest priority experiment at

the Bates laboratory. Dr. Dodge has been an expert adviser on the hazards

and use of highly active tritium targets (100 kCu). Dr. Lightbody and

Maruyama have participated in an earlier tritium experiment here at NBS.

During this past year and under an agreement between the Naval Postgraduate School and the National Bureau of Standards, X. K. Maruyama was assigned to the Naval Postgraduate School (NPS) as a faculty replacement

for the Director of the NPS electron linear accelerator. There he was involved in the study of the Cerenkov radiation phenomenon. In particular, the diffraction aspects of Cerenkov radiation, the coherent effects

of electron "bunching," and the harmonic nature of Cerenkov radiation

from a periodic electron source were observed at microwave frequencies.

Theoretical calculations were done to predict subthreshold Cerenkov radiation and form factor effects which might be important for intense electron

beams. The feasibility of observing x-ray Cerenkov radiation at frequencies corresponding to atomic electron absorption edges was investigated.

Proposals to Other Agencies . This year a proposal was submitted to

the DoE for construction of a large magnetic spectrometer which would be

used with the RTM when it becomes operational. This proposal comes from a consortium of several universities. The magnet optics and all spectrometer details were provided by Ingvar Blomqvist of MIT. E. Hayward led

this effort. At this time we have had no official DoE reaction to this

proposal

.

In addition to the spectrometer proposal, a separate proposal to the

DoE to provide minimal equipment for coincidence experiments is being

prepared by J. W. Lightbody. In this proposal we ask for funding to

purchase solid state telescopes, a scattering chamber, and miscellaneous

hardware required to perform prototype (e,e'p) coincidence measurements

266
Nuclear Physics, Technical Activities (cont'd.)

with the RTM. For this purpose the (e,x) spectrometer is being converted

(by addition of a drift chamber presently under construction) to

application as an electron spectrometer.

Miscellaneous Activities . During this year Dr. Hayward prepared an extensive review paper on virtual photon theory and electrodisintegration

experiments. She delivered this work at the Verona summer school on Intermediate Energy Nuclear Physics. In addition to this, she is actively

involved in electrodisintegration experiments on 90 Zr and 92 Zr (Dodge and

Hayward) and together with Dodge is working on a very fundamental aspect

of current conservation known as Siegert's Theorem, in which the relation

between Coulomb and transverse electromagnetic nuclear excitation can be

studied. Dr. Hayward is also participating in photon scattering experiments at Mainz using their operating cw accelerator as well as their

pulsed linac.

Drs. Dodge and O'Connell have also been working on development of

detectors for use in a polarized electron scattering coincidence measurement at Bates. This measurement will be the first of its kind and will access a heretofore inaccessible nuclear structure function. They will use the reaction, (e,e'p), to look at the knockout protons with a high

purity germanium detector telescope. This type detector has broad application in other coincidence experiments, and represents in some cases a much less expensive approach than through the use of large and extremely

expensive magnetic spectrometers.

Finally, a number of people in the Group are involved in the planning

of CEBAF, the future 4 GeV national electron facility for nuclear physics.

Lightbody has chaired the Magnetic Spectrometer Working Group and worked

on (e,e'2N) and other reaction calculations for planning the basic experimental program. O'Connell has made many detailed calculations of nucleon

knockout, pion production, and delta production processes for this same purpose, and is involved in summary activities of the summer long CEBAF

Summer Study Group.

We feel that the Nuclear Physics program represents long range NBS

goals in nuclear research, and there is a growing vitality from measured

involvement with the larger nuclear research community. The theoretical

efforts cover the full spectrum of current interest in nuclear research.

The experimental effort represents a healthy balance between in-house

research and research at other facilities.

267
INVITED TALKS

Division 530.01 Nuclear Physics

Danos, M., "Relativity in Terrestrial Physics: Why Bother?," Naval

Research Laboratory, Washington, D.C., January 10, 1985.

Dodge, W. R., "Virtual Photons in Theory and Experiment," Conference on the Applications of Accelerators in Research and Industry; Denton, Texas;

November 13, 1984.

Dodge, W. R., "Measurement of the Fifth Response Function in the (5,e'x)

Cross Section," CNFQ, Rio de Janeiro, Brazil; November 20, 1984.

Hayward, E., "Photon Absorption and Scattering in the A-Resonance Region,"

MIT, Boston, MA, November 1984.

Hayward, E., "High Energy Photon Scattering Experiments," Photon

Scattering Workshop, Brookhaven National Laboratory, Upton (L.I.) NY,

November 25, 1984.

Hayward, E., "Electrodisintegration Experiments and Virtual Photon

Spectra," International School of Intermediate Energy Nuclear Physics,

Verona, Italy, June 1985.

Hayward, E., "NBS Electrodisintegration Experiment," University of Genoa,

Genoa, Italy, June 1985.

Lightbody, J. W., Jr., "Experiments at the Continuous Electron Beam

Accelerator Facility," Memphis Meeting of the American Physical Society

(Division of Nuclear Physics), Memphis, TN, October 26, 1984.

Lightbody, J. W., Jr., "Perspectives in Intermediate Energy Nuclear

Physics," Conf. on Electromagnetic Interactions of Nuclei at Low and

Medium Energies, Moscow, USSR, December 10-12, 1984.

Lightbody, J. W., Jr., "Electronuclear Studies at NBS," Univeristy of

Mainz, Mainz, Germany, December 1984.

Lightbody, J. W., Jr., "Nuclear Research with the RTM," University of

Lund, Lund, Sweden, December 1984.

Lightbody, J. W., Jr., "Summary: Moscow Conference on Intermediate

Energy Nuclear Physics," George Washington University, Washington, D.C.,

February 11, 1985.

268
Division 530.01, Invited Talks (Cont'd)

Lightbody, J. W., Jr., "Current Status and Issues Facing the Magnetic

Spectrometer Working Group," CEBAF 1985 Summer Workshop, Newport News, VA,

June 1985.

Lightbody, J. W., Jr., "Summary: Magnetic Spectrometer Working Group,"

CEBAF 1985 Summer Workshop, Newport News, VA, June 1985.

Lightbody, J. W., Jr., "Physics Questions Facing CEBAF," Lewis Center for

Physics, Lewes, DE, June 1985.

Lightbody, J. W., Jr., "Two-Nucleon Knockout Reactions ," CEBAF 1985

Summer Workshop, Newport News, VA, July 1985.

Lightbody, J. W., Jr., "Nuclear Research with the NBS rtm," NBS

Gaithersburg, MD, August 1985.

Maruyama, X. K., "Cerenkov Radiation Research," Center for Radiation

Research, NBS, Gaithersburg, MD, March 7, 1985.

Maruyama, X. K., "Structure Factors in Cerenkov Radiation," Naval

Postgraduate School, Monterey, CA, March 29, 1985.

Maruyama, X. K., "Microwave Cerenkov Radiation," San Jose State

University, San Jose, CA, April 1985.

Maruyama, X. K., "Cerenkov Radiation Research at the Naval Postgraduate

School," Electrotechnical Laboratory, Tsukuba, Japan, May 28, 1985.

Maximon, L. C., "High Energy Electron Scattering - Theoretical Corrections

to Experimental Data," Georege Washington University, Washington, D.C.,

February 25, 1985.

Maximon, L. C., "The Radiative Tail in High Energy Electron-Nucleus

Scattering," The XXV Cracow School of Theoretical Physics, Zakopane,

Poland, June 112, 1985.

Meshkov, S., "A New Resonance at 8.3 GeV - Interesting?" Center for

Radiation Research, NBS, Gaithersburg, MD, October 11, 1984.

Meshkov, S., "Extensions of the Standard Model," Los Alamos National

Laboratory, Los Alamos, NM, November 15, 1984.

Meshkov, S., "Chiral Fermions," University of Wisconsin, Madison, WI,

May 6, 1985.

269
Division 530.01, Invited Talks (Cont'd)

Meshkov, S., "Chiral Fermions," University of Cincinnati, Cincinnati, OH,

May 9, 1985.

Meshkov, S., "Glueballs," University of Cincinnati, Cincinnati, OH, May 9,

1985.

O'Connell, J. S., "Neutrino-Nucleus Reactions," University of Wisconsin - Workshop on Neutrino Interactions, Madison, WI, November 28, 1984.

O'Connell, J. S., "Polarized Electron Scattering on Nuclei," Bates Linear

Accelerator Center, Middleton, MA, December 13, 1984.

O'Connell, J. S., "Electromagnetic Reactions in the Delta Region,"

University of Virginia, Charlottesville, VA, January 22, 1985.

O'Connell, J. S., "Electromagnetic Reactions in the Delta Region,"

University of Illinois, Champaign, IL, March 6, 1985.

O'Connell, J. S., "New Fission Results," Lewes Center for Physics, DE,

June 18, 1985.

O'Connell, J. S., "Nucleon Production by GeV Electrons," CEBAF 1985 Summer

Workshop, Newport News, VA, August 16, 1985.

270
PUBLICATIONS

Division 530.01 Nuclear Physics

Adler, J. 0., Blomqvist, K. I., Calarco, J. R., O'Connell, J. S.,

Connelly, J., Dodge, W. R., Hansen, K. , Hersman, W., Lightbody, J. W. Jr.,

Nilsson, D., Sandell, A., and Schr0der, B., "A Study of the Reaction

238 U(e,e'f) in the Delta Region with 720 MeV Electrons," Proc. Nuclear

Physics with Electromagnetic Probes, Paris, France, July 1985.

Ahrens, J., and O'Connell, J. S., "Mass Independence of the

Electromagnetic Nuclear Response in the Delta Region," Comments on Nuclear

and Particle Physics, 1985.

Beck, D. H., Kowalski, S. B., Schulze, M. E., Turchinetz, W. E.,

Lightbody, J. W. , Jr., Maruyama, X. K. , Stapor, W. J., Caplan, H. S.,

Retzlaff, G. A., Skopik, D. M., Galoski, R., Tritium Form Factor at Low q,

Phys. Rev. C, 30 (1984).

M. Danos, V. Gillet, and M. Cauvin, Methods in Relativistic Nuclear

Physics , North Holland (Amsterdam, Oxford, New York, Tokyo) 1984.

M. Danos and A. Johnson, Non-Observability of Non-Exponential Decay,

Phys. Rev. D30, 2692 (1984).

M. Danos and J. Rafelski, Pocketbook of Mathematical Functions , Harri Deutsch (Thun, Frankfurt/Main) 1984.

Delsanto, P. P., Biedenharn, L. C., and Danos, M., Interaction of QuasiClosed Channels with Open-Channel Continuum, Nuovo Cimento Lett. 42, 59

(1985).

Dodge, W. R., "Virtual Photons in Theory and Experiment," Nucl. Instr.

Methods in Physics Research B10/ 11 , 432 (1985).

Dodge, W. R., "An Estimate of Proton Yield from Quasi -El astic Scattering

on 16 0 at an Incident Energy of 800 MeV," Proc. Nuclear Physics with

Electromagnetic Probes; Paris, France, July 1985.

Fishbane, P. M. and Meshkov, S., "Glueballs," Comments on Nuclear and

Particle Physics _13, No. 6, p. 325 (1984).

Fishbane, P. M., Meshkov, S., and Norton, R. "Chiral Fermions beyond the

Standard Model," Phys. Rev. D31 , 1119 (1985).

Fishbane, P. M., Gaemers, K., Meshkov, S., and Norton, R. "Experimental

Consequences of a Heavy Neutral Fermion," Phys. Rev. D32, (1985).

271
Division 530.1, Publications (cont'd)

Hayward, E., "Absorption and Scattering of Photons by the A-Resonance,"

Proc. Conf. on Neutron Capture Gamma Ray Spectroscopy, Published by AIP,

1985.

Lane, K., Meshkov, S., and Wilczek, F., "Possible Interpretation of a New

Resonance at 8.3 GeV," Phys. Rev. Lett. 53, 1718 (1984).

Lightbody, J. W. Jr., "Perspectives in Medium Energy Electro- and PhotoNuclear Reactions," Proc. Conf. on Electromagnetic Interactions of Nuclei

at Low and Medium Energies, Moscow, USSR, December 10-12, 1984.

Lightbody, J. W. Jr., "Current Status and Issues Facing the Magnetic

Spectrometer Working Group," Proc. CEBAF 1985 Summer Workshop, June 1985.

Lightbody, J. W. Jr., "Summary, Magnetic Spectrometer Working Group,"

Proc. CEBAF 1985 Summer Workshop, June 1985.

Martins, M. N., Hayward, E., Lamaze, G., Maruyama, X. K., Schima, F. J.,

Experimental Test of the Bremsstrahl ung Cross Section, 30 (1984).

Maruyama, X. K., and Zurey, E. C., Jr., A Flash X-Ray Facility for the

Naval Postgraduate School, Naval Postgraduate School Technical Report No.

61-85-004, June 1985.

Maximon, L. C. and LePretre, A., Angular Distribution of High Energy

Electrons Following Radiation, NBSIR 84-2854 (1985).

O'Connell, J. S., Dodge, W. R., Lightbody, J. W., Jr., Maruyama, X. K.,

Adler, J. 0., Hansen, K. , Schroder, B., Bernstein, A. M. , Blomqvist, K.

I. , Cottman, B. H., Comuzzi , J. J., Miskimen, R. A., Quinn, B. P.,

Electron Scattering in the Excitation Region of the Delta Resonance on Nuclei with A=1 to 16, Phys. Rev. Lett., j33>. No. 17 (1984).

O'Connell, J. S., "Nuclear Production by GeV Electrons," Proc. CEBAF

Summer Study, September 1985.

J. Rafelski and M. Danos, Nuclear Matter Under Extreme Conditions in

Hadrons and Heavy Ions , Proc. Summer School at University of Cape Town,

January 11-27, 1984. Edited by W. D. Heiss, Lecture Notes in Physics,

231, Spri nger-Verl ag, Berlin, Heidelberg, New York, Tokyo (1984).

272
PUBLICATIONS IN PREPARATION

Division 530, Nuclear Physics

M. Danos and J. Rafelski, Formation Conditions of Quark-Gluon Plasma a Central Rapidity, Physical Review (to be published).

Danos, M. and Johnson, A., "Quarks in the Nuclear Ground State" (submitted

to J. Phys. _G.

)

Danos, M., Kohmura, T., Suzuki, T., Cauvin, M., and Gillet, V., "Shell

Model Interaction Energies in a Relativistic Hamiltonian Formulation,"

(accepted for publication in Nuclear Physics.)

Dodge, W. R., Hayward, E., Martins, N. M. , and Wolynec, E., "(e,p) and

(e,a) Reactions in 90 Zr and 92 Zr," (to be published in Phys. Rev. C.

)

Dodge, W. R. and Hayward, E., "Siegerts Theorem and Nuclear

Electrodisintegration," (submitted to Phys. Rev.)

Jacobs, S., Olsson, M. G., Kaus, P., and Meshkov, S., "Direct Test of a Monte Carlo Lattice Gauge Heavy Quark Potential," (submitted to Phys.

Lett. B_.

)

Maruyama, X. K., Neighbours, J. R., Buskirk, F. R., Electron Beam Bunch

Profile Determination Through Cerenkov Radiation, IEEE Transactions in

Nuclear Science (in press).

Maruyama, X. K., Neighbours, J. R., Buskirk, F. R., Snyder, D. D.,

Vujakllja, M. , Bruce, R. G. , Observation of Microwave Cerenkov Radiation

as a Diffraction Pattern, J. Appl. Phys. (to be submitted).

Neighbours, J. R., Maruyama, X. K., Onset of Cerenkov Radiation,

Proceedings of the SDIO/DARPA/ Services Annual Propagation Review 1985 (in

press).

Neighbours, J. R., Buskirk, F. R., Maruyama, X. K., Emission Threshold for

Cerenkov Radiationk J. Appl. Phys. (submitted).

273
TECHNICAL AND PROFESSIONAL COMMITTEE PARTICIPATION AND LEADERSHIP

Division 530.01 Nuclear Physics

Danos, M.

Chairman, NBS Colloquium Committee

Dodge, W. R.

Member, MIT/Bates Accelerator Laboratory Hazards Committee

Hayward, E.

Chairman, Division of Nuclear Physics of the American Physical

Society.

Member, Program Committee, Division of Nuclear Physics of the

America! Physical Society.

Member, Board of Trustees, Southeastern Universities Research

Association (SURA).

Member, SIRA Subcommittee on Public Information.'

Chairman, Nominating Committee, Continuous Electron Beam Accelerator

Facility (CEBAF) User Group.

Member, NML Women's Personnel Committee.

Lightbody, J. W., Jr.

Chairman, National Advisory Board, Continuous Electron Beam

Accelerator Facility, Newport News, VA.

Member, Program Advisor, Committee, MIT/Bates Linear Accelerator.

Member, Technical Advisory Committee, MIT/Bates Linear Accelerator.

Member, Nominating Committee, Bates Linear Accelerator User Group.

Member, Board of Directors, CEBAF Users Group.

Member, Program Committee, Division of Nuclear Physics of the APS.

Chairman, Magnetic Spectrometer Working Group, CEBAF.

274
Division 530.01 Technical and Professional Committee Participation and

Leadership (cont'd)

Member, Program Advisory Committee, Saskatchewan Linear Accelerator

Laboratory

Maruyama, X. K.

Chairman, Radiological Safety and Isotopes Committee, Naval

Postgraduate School, Monterey, CA.

Member, Minority Advisory Committee, National Measurement Laboratory,

National Bureau of Standards.

Meshkov, S.

Member, Board of Advisors, Aspen Center for Physics, Aspen, CO.

Member, Board of Advisors, Lewes Center for Physics, Lewes, DE.

Member, LAMPF II Planning Committee, Los Alamos, NM.

Member, Organizing Committee, Aspen Winter Physics Conference, Aspen,

CO.

Member, Program Committee, Aspen Center for Physics, Aspen, CO.

Member, Attendee Selection Committee, Aspen Center for Physics,

Aspen, CO.

O'Connel 1 , J. S.

Member, Nominating Committee, APS Division of Nuclear Physics.

Member, Directors Advisory Committee, MIT/Bates Linear Accelerator.

Vice-Chairman, Bates Accelerator User Group.

Member, Organizing Committee, Nation Nuclear Physics Summer School,

Georgetown University.

275
JOURNAL EDITORSHIPS

Division 530.01 Nuclear Physics

O'Connell, J. S, Member, Editorial Board, Physical Review £ (Nuclear

Physics)

.

276
TRIPS SPONSORED BY OTHERS

Division 530.01 Nuclear Physics

M. Danos, Trip to Saclay Center for Nuclear Studies to work on joint

research, sponsored by Saclay, Spring, 1985.

W. R. Dodge, Two trips to MIT sponsored by the MIT/Bates Accelerator

Laboratory, to attend meetings of the Tritium Hazards Committee, January

and September 1985.

E. Hayward, Trip to MIT to give seminar, sponsored by MIT, November 1985.

E. Hayward, Travel expenses to the Nuclear Physics Laboratory of Oxford

University, Oxford, Endland paid by Oxford, July 1985.

J. W. Lightbody, Jr., Traveled to MIT to attend MIT/Bates Technical

Advisory Panel Meeting, trip sponsored by MIT, January 1985.

J. W. Lightbody, Jr., Traveled to Moscow, USSR, to give invited talk,

expenses in the Soviet Union paid by the Soviet Government, December

1985.

J. W. Lightbody, Jr., Traveled to CEBAF (Newport News, V A) to attend

conference and give two talks, sponsored by CEBAF, June 3-7, 1985.

X. K. Maruyama Traveled to the Naval Postgraduate School for temporary

assignment (research, teaching, and supervisory roles) sponsored by the

Naval Postgraduate School, Monterey, California (August 1984 - September

1985).

X. K. Maruyama attended and presented a paper at the 1985 Accelerator

Conference in Vancouver, B.C. (May 13-16, 1985), sponsored by NPS.

X. K. Maruyama attended a workshop on the Advanced Test Accelerator,

Lawrence Livermore National Laboratory, Livermore, CA. (April 8, 1985),

sponsored by NPS.

X. K. Maruyama traveled to the Linac at the Electrotechnical Laboratory,

Tsukuba, Japan and presented a talk (May 28, 1985).

X. K. Maruyama visited the Naval Surface Weapons Center, White Oak, MD;

Harry Diamond Laboratory, Silver Spring, MD; Naval Research Laboratory,

Washington, D.C.; and Physics International, San Leandro, CA, to confer

about flash x-ray machine for the Naval Postgraduate School (March 1985),

sponsored by NPS.

277
Division 530.01, Trips Sponsored by Others (cont'd)

L. C. Maximon, Traveled to the Saclay Accelerator Laboratory, Paris

France, Expenses in France paid by Saclay; April 1985.

L. C. Maximon, Trip to Poland sponsored by Polish government, to lecture

at Nuclear Physics Summer School, June 12, 1985.

S. Meshkov, Trip to Los Alamos National Laboratory to give a theoretical

seminar was sponsored by Los Alamos, November 15, 1984.

S. Meshkov, Trip to Caltech to work on collaborative research sponsored by

Caltech (March 3 - April 22, 1985).

S. Meshkov, Trip to University of Wisconsin Elementary Particle Conference

and give a seminar was sponsored by the University of Wisconsin (May

1985).

S. Meshkov, Trip to University of Cincinnati to give a theoretical seminar

was sponsored by the University of Cincinnati (May 9, 1985).

S. Meshkov, Trip to the Institute for Theoretical Physics at U.C. Santa

Barbara, to work on collaborative research was sponsored by UCSB.

J. S. O'Connell, Trip to University of Virginia to give seminar sponsored

by University of Virginia, January 22-23, 1985.

J. S. O'Connell, Trip to University of Illinois to give seminar sponsored

University of Illinois, March 6-7, 1985.

J. S. O'Connell, Trip to CEBAF (newport News, V A) to work on physics

program of CEBAF sponsored by CEBAF; August 4-17, 1985.

278
SPONSORED SEMINARS AND COLLOQUIA

Division 530.01, Nuclear Physics

Marcella Sanzone, Instituto di Scienze Fisiche, Uni versi t&di Genova,

Genova, Italy, "Deuteron Photodisintegration Between 100 and 260 MeV"

,

October 4, 1984.

Richard Deslattes, Center for Basic Standards, NBS, "Second Generation

Lamb Shift Measurements", October 11, 1984.

Sydney Meshkov, Center for Radiation Research, NBS, "A New Resonance at

8.3 GeV--Interesting?" , October 18, 1984.

David Dowell, Brookhaven National Laboratory, "Proton Capture to Giant

Resonances Built on Highly Excited States", October 30, 1984.

Masami Yamada, Waseda University, Tokyo, Japan, "Partly Frozen Liquid-Drop

Model of Atomic Nuclei", November 21, 1984.

Moshe Gai, Yale University, "Dipole Collectivity in Nuclei", November 30,

1984.

Richard Pehl , Lawrence Berkeley Laboratory, "Double Beta Decay", December

18, 1984.

Peter Zimmerman, Louisiana State University, "A Physicist Looks at Arms

Control", January 24, 1985.

Barry Berman, George Washington University, "Channeling Radiation",

February 7, 1985.

Thomas Gaisser, Bartol Research Foundation-Franklin Institute, University

of Delaware, "Cosmic Ray Cascades in the Atmosphere", February 21, 1985.

X. K. Maruyama, Center for Radiation Research and Naval Postgraduate

School, NBS, "Microwave Cherenkov Radiation", March 7, 1985.

Malcolm J. Cooper, University of Warwick, United Kingdom, "Who Discovered

the Compton Effect?", March 28, 1985.

E. G. Fuller, Center for Radiation Research, NBS, "Review of Photonuclear

Cross-Sections for p-Shell Nuclei", March 21, 1985.

Paul Stoler, Rensselaer Polytechnic Institute, "Photopion Production in pShell Nuclei", April 11, 1985.

279
Division 532, Sponsored Seminars and Colloquia (cont'd.)

Branka AntolkoviC, Institut Ruder BcrskoviC, Zagreb, Yugoslavia,

"Nultiparticle Breakup of Light Nuclear Systems", May 20, 1985.

Michael Weyrauch, University of Virginia, Charlottesville, V A, "NonNucleon Degrees of Freedom in Nuclear Photon Scattering", May 28, 1985.

W. Greiner, University of Frankfurt, West Germany, "Puzzles in High Z Atomic and Nuclear Physics", July 24, 1985.

280
S3S-1 1 4 A qg y. 2-8C u.s. :e»T. of comm. BIBLIOGRAPHIC DATA

SHEET See instructions)

1. PUBLICATION OR

REPORT NO. NBSIR-85/3232

2. Performing Organ. Report No. 3. Publication Date OCTOBER 1965

4 . title and subtitle

Technical Activities 1985

Center for Radiation Research

5. AUTPOR(S)

Chris E. Kuyatt

6. PERFORMING ORGANIZATION (If joint or other than MBS. see in struct/on s)

national bureau of standards

DEPARTMENT OF COMMERCE

WASHINGTON. D.C. 20234

7. Contract/Grant No.

8. Type of Report & Period Covered

9. SPONSORING ORGANIZATION NAME AND COMPLETE ADDRESS (Street. City. State. ZIP)

10. SUPPLEMENTARY notes

_

Oocument describes a computer program; SF-185, FIPS Software Summary, is attached.

11. ABSTRACT i A 200-word or less factual summary of most significant information. If document includes a significant

oibliography or literature survey, mention it here/

This report summarizes research projects, measurement method development,

calibration and testing, and data evaluation activities that were carried

out during Fiscal Year 1985 in the NBS Center for Radiation Research.

These activities fall in the areas of atomic and plasma radiation,

radiation physics, radiometric physics, radiation sources and

instrumentation, ionizing radiation, and nuclear physics.

12. KEY WORDS (Six to twelve entries; alphabetical order; capitalize only proper names; and separate key

Atomic radiation, ionizing radiation; measurement support; nuclear

radiation; plasma radiation; radiation instrumentation, radiation

measurements; radiation physics, radiation sources; radinmpfrir phyci

words by semi colon s)

13. availability 14. NO. OF

PRINTED PAGES

fin Unlimited

1 For Official Distribution. Do Not Release to NTIS 285

! Order From Superintendent of Documents, U.S. Government Printing Office, Washington, D.C. J 20402. 15. Price

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Order From National Technical Information Service (NTIS), Springfield, VA. 22161 $22.95

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