A 11 ID 2 ^03220

PUBLICATIONS

NISTXR 88-3869

Center for

Radiation

Research

QC

100

• U56

#88-3869

1988

c.2

U.S. DEPARTMENT OF COMMERCE

National Institute of Standards and Technology

NISTIR 88-3869

C.2,

Center for

Radiation

Research

1988

Technical Activities

November 1988

Chris E. Kuyatt, Director

Center for Radiation Research

National Measurement Laboratory

U.S. Department of Commerce, C. William Verity, Secretary

National Institute of Standards and Technology, Ernest Ambler, Director

ABSTRACT

This report summarizes research projects, measurement method development,

calibration and testing, and data evaluation activities that were carried

out during Fiscal Year 1988 in the NIST 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.

i
INTRODUCTION

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

Center for Radiation Research (CRR) for the period October 1, 1987 to

September 30, 1988. 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 ionizing 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 ionizing radiation data bases in order to meet the

major demands of the Nation for such data; and participates in

collaborative efforts with other NIST centers in the interdisciplinary

applications of radiation.

This report summarizes the activities that were carried out by the

five divisions and one group that comprised the Center for Radiation

Research (CRR) for most of the fiscal year 1988. Specifically the six

CRR units included the Atomic and Plasma Radiation Division, the

Radiation Physics Division, the Radiometric Physics Division, the

Radiation Source and Instrumentation Division, the Ionizing Radiation

Division, and the Nuclear Physics Group. Toward the end of that year,

however, two divisions, the Atomic and Plasma Radiation Division and the

Radiation Physics Division were detailed to the new CAMOP unit.

Therefore, we have included both the organizational chart for the old CRR

structure and the chart showing the new structure in this report. 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 Institute of

Standards and Technology, Gaithersburg, MD 20899.

li
Table of Contents

ABSTRACT i

INTRODUCTION ii

CRR ORGANIZATION CHART - STRUCTURE DURING FY 88 vii

CRR ORGANIZATION CHART - CURRENT STRUCTURE FOR FY 89 viii

ATOMIC AND PLASMA RADIATION - Division 531 1

Atomic Spectroscopy Group 4

Atomic Radiation Data Group 9

Plasma Radiation Group 14

Invited Talks 18

Publications 20

Publications in Preparation 25

Technical & Professional Committee Participation & Leadership .... 28

Major Consulting and Advisory Services 30

Journal Editorships 32

Trips Sponsored by Others 33

Calibration Services Performed 35

Sponsored Seminars and Colloquia 36

RADIATION PHYSICS - Division 533 39

Far Ultraviolet Physics Group 42

Electron Physics Group 48

Photon Physics Group 56

Sponsored Workshops, Conferences, and Symposia 65

Invited Talks 66

Publications 69

Publications in Preparation 73

iii
Technical & Professional Committee Participation & Leadership 75

Major Consulting and Advisory Services 77

Journal Editorships 79

Trips Sponsored by Others 80

Calibration Services Performed 82

Sponsored Seminars and Colloquia 83

RADIOMETRIC PHYSICS - Division 534 87

Spectral Radiometry 89

Spectrophotometry Group 94

Radiometric Measurement Services Group 97

Invited Talks 102

Publications 104

Publications in Preparation 106

Technical & Professional Committee Participation & Leadership 108

Book and Journal Editorships Ill

Standards Committee Meetings 112

Major Consulting and Advisory Services 113

Standard Reference Materials 114

Measurement Assurance Services 116

Calibration Services Performed 117

Trips Sponsored by Others 118

Sponsored Seminars and Colloquia 119

rv
RADIATION SOURCE AND INSTRUMENTATION - Division 535 121

CW Racetrack Microtron Project 121

Free-Electron Laser Facility 124

High-Current RTM Injector Project 129

Accelerator Operations 132

Mechanical Instrumentation 133

Electronics Instrumentation 133

Radiation Instrumentation Standards 134

Invited Talks 137

Publications 138

Publications in Preparation 140

Technical & Professional Committee Participation & Leadership .... 141

Major Consulting and Advisory Services 143

Sponsored Seminars and Colloquia 144

IONIZING RADIATION DIVISION - Division 536 145

Office of Radiation Measurement 147

Radiation Interactions and Dosimetry Group 152

Neutron Interactions and Dosimetry Group 169

Radioactivity Group 180

Invited Talks 187

Publications 192

Publications in Preparation 199

Technical & Professional Committee Participation & Leadership .... 206

Major Consulting and Advisory Services 216

v
Journal Editorships 222

Trips Sponsored by Others 223

Standard Reference Materials 226

Calibration Services Performed 227

Sponsored Seminars and Colloquia 231

NUCLEAR PHYSICS GROUP - 530.1 233

Invited Talks 238

Publications 241

Technical & Professional Committee Participation & Leadership 243

Major Consulting and Advisory Services 245

Trips Sponsored by Others 246

Journal Editorships 247

Sponsored Seminars and Colloquia 248

LIST OF ACRONYMS 249

vi
CENTER

FOR

RADIATION

RESEARCH

vii

NOT
FOR

RADIATION

RESEARCH
TECHNICAL ACTIVITIES

Division 531, Atomic and Plasma Radiation Division

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, wavelengths, and transition

probabilities. Since in most cases atomic radiation originates from

plasmas, we are also engaged in research on the effects of the plasma

environment on atomic radiation, such as studies of spectral line

broadening and line shifts. We explore these effects in order to gain an understanding of atomic processes in plasmas as well as to utilize them

for the development of new measurement techniques. Furthermore, welldefined atomic radiation sources are also developed as VUV radiometric

standards and wavelength standards.

Our activities, which support many areas of science and technology,

are undergoing significant changes in direction, since appreciable

changes have occurred in the external forces that drive our priorities.

There is, for example, much increased demand for the detailed

understanding of atomic processes in cool plasmas, both for modelling

purposes and diagnostics. These needs have arisen mainly from materials

processing by plasmas, such as the widely used plasma etching of

semiconductors, as well as surface cleaning by plasmas, and materials

deposition by plasma sputtering techniques. For commercial applications,

the understanding of all these processes on the atomistic level is the

key to optimizing the operating conditions and to achieving competitive

advantages. Likewise, process monitoring and modelling in plasma

chemistry and spectrochemistry can be achieved on a fundamental level

only with reliable atomic radiation and collision data. For these

technologies heavy neutral elements, including rare earths, are of

principal interest.

Very different demands arise from VUV and X-ray laser physics. In

this research area, transition energies and lifetimes (or radiative decay

rates) of highly stripped ions are essential for the selection and

testing of potential laser systems. VUV and X-ray laser research has not

only assumed importance for defense applications, but also for biological

and bio-medical studies (e.g. the "water window"). We are very active

both in generating atomic data, and in the development of lasing schemes.

Also, the nation's research program on magnetic fusion energy is steadily

progressing, and the atomic data we produce for highly stripped heavy

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

ions are needed there for modelling the cross-field ion transport, for

estimating the effects of impurities on the plasma energy balance, and

for plasma diagnostics, such as the measurement of ion temperatures.

Beyond this, there is also the fundamental scientific need for an experimentally well-tested, fully relativistic atomic structure theory

that accurately describes the properties of highly ionized as well as heavy atoms, including QED effects. Finally, our vacuum ultraviolet

radiometry work with plasma sources is now providing miniaturized

calibrated radiation source packages to allow radiometric calibrations on board spacecraft. These 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 Plasma Radiation. It currently

has 17 professional physicists, among them 16 Ph.D.s. During 1988 the

division has had 17 guest scientists, from China (2), Israel (3), India

(1), Sweden (3), Canada (1) and U.S.A. (7).

Some of our significant accomplishments during the past year are:

• We have proposed and are involved in experiments, with NRL and KMS

Fusion groups, on two new X-ray and XUV laser schemes: Lasing at

26 A in l 2A+ ions and at 600 A in Mo6+ ions, and patent

applications and manuscripts are underway.

• We have demonstrated population inversion and gain in a C IV line

in the theta pinch recombining plasma. Experiments in

collaboration with Bell Labs, with a reflective cavity give a gain

of 12 for the 253 nm UV transition in C IX.

• We have published, or have in press, several major critical data

compilations

Spectral data tables for all or most ions of Fe , Ni, Cu and Mo.

Transition probability tables for all atoms and ions of the iron

group elements Sc through Ni - to be published in two volumes of

500 pages each.

• We have devised a very sensitive and clean experimental test of

possible violations, or confirmation, of the Pauli Exclusion

Principle (PEP) by looking for a helium transition whose very

existence would be a consequence of PEP violations, and a preliminary experiment is in preparation.

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

• A procedure to accurately represent electron- impact excitation

cross sections of ions in compact formulas has been developed and

applied to relativistic distorted-wave Born cross sections of Belike and Na-like ions. This is an ideal method to accurately

condense the inherently massive volume of data required in

modeling applications such as short-wavelength laser design and

fusion plasma diagnosis.

• Advanced versions of computer codes to calculate nonre lativistic

and relativistic wave functions and transition probabilities have

been developed and are being tested for a wide range of atoms and

ions. In addition, methods to calculate QED corrections for manyelectron atoms are being developed. Theoretical energy levels

from these codes are sufficiently accurate to complement highprecision spectroscopic measurements.

These and other activities are discussed in the following sections,

where the principal work of the three technical groups during the past

year is described.

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

I . Atomic Spectroscopy Group

(a) Highly Ionized Atoms

The energy levels and wavelengths for spectra of highly ionized

atoms are of basic interest for testing theoretical descriptions of

atomic properties, which are affected by large relativistic and quantumfield (QED) contributions. They are also necessary data for the modeling

and diagnostics of high- temperature plasmas occurring in x-ray laser

research, nuclear fireballs, solar flares, tokamaks and other fusionresearch machines, etc. We have excited very highly charged ions in

several sources: the highest temperatures were obtained in plasmas

produced by the OMEGA laser at Rochester, and we have also used plasmas

obtained with lasers at Los Alamos and NIST, plasmas generated in the

TEXT tokamak at the University of Texas, and sliding-spark and vacuum- spark plasmas at NIST.

We completed analyses of the spectra of Al-like ions (Cu16+

through Mo29+

) and K-like ions (Cu10+ through Mo23+) obtained with the

TEXT tokamak. The energy levels of these ions were compared with Dirac

Fock calculations to test the theory and to use the smooth variation of

the deviations from experiment for interpolations along the isoelectronic

sequences. One result of the comparisons was that inclusion of

previously uncalculated QED corrections for the M-shell electrons

substantially improved agreement between theoretical and experimental

values for the 3s 2 3p 2 P ground- term doublet splitting of the Al-like

ions. The experimental wavelengths from these measurements are sufficiently accurate to be used as standards in fusion-plasma and x-ray

laser plasma research. Similar work on ions of the Mg and Cl

isoelectronic sequences is in progress (J. Sugar, V. Kaufman, Y.-K. Kim).

We finished work on prominent transitions in the Fe-like ions

Ru18+ to Gd38+

. The spectra were obtained from laser-produced plasmas at

NBS , Los Alamos, and Rochester. The energy levels for this sequence were

also compared with calculations of the Dirac-Fock relativistic type and

the differences were used to accurately predict missing levels and levels

for ions not observed. Wavelengths for forbidden (magnetic-dipole)

transitions between levels of the 3p 6 3d8 ground configuration, which are important for tokamak plasma diagnostics, were derived from the

experimental levels. We have papers in press on the spectra and energy

levels of gallium-like ions Rb6+ to Mo 11+ and germanium- like ions Rb 5+ to

Mo 10+ ( J . Reader and collaborators from Lund University, Sweden, and the

Naval Research Laboratory)

.

During the coming year we plan visits to both the TEXT tokamak

and the Rochester OMEGA laser facility to excite higher- temperature

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

spectra of heavy elements. One of the experiments planned for the

Rochester visit is to extend our previous work on Na-like spectra to the

rare-earths region of the periodic table ( 50 to 60 electrons stripped

from the atoms) . The one-electron spectra of this sequence are of

special theoretical interest, and accurate measurements of the highionization stages are also needed for both x-ray laser and magneticfusion research.

(b) Atomic-ion x-ray lasers

J. Sugar, collaborating with P.D. Morley (KMS Fusion), has

predicted that inner-shell photoionization can produce lasing at

wavelengths below 50 A in plasmas generated from laser-exploded foils.

Sugar worked out the case for copper-like iodine (I 2A+

) which should lase on the 3d9 4s 2 -* 3d10 4p doublet calculated at 24.565 and 26.026 A (see

figure). Experiments to test the idea are underway at KMS fusion, and a joint paper is in press.

Scheme for 26 A laser in Cu - like iodine (

I 24 -

)

Zn * Like iodine

J. Reader's work on the spectra of molybdenum ions revealed a coincidence between a Mo6+ line and a Mo 11+ line at 136.50 A. Reader and

U. Feldman (Naval Research Lab) have proposed a scheme for Mo6+ lasing at

600 A based on using the 136. 5-A Mo 11+ line to photopump the upper level

of the coincidence transition in Mo 6+ (see figure) . Experiments to test

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

the idea are underway. Reader has discovered that a previous analysis of

the Mo 6+ spectrum done in another laboratory is totally erroneous. He is

now analyzing this spectrum to identify the candidate lasing transitions

and has found all levels of 5 principal configurations.

(c) Laser Spectroscopy and High-Accuracy Determinations of Atomic

Energy-Level Structures

A basic objective of our laser spectroscopy program is to test

experimentally the most accurate theoretical calculations for selected

atoms. The development of theoretical methods that treat electroncorrelation, relativistic, and QED energy contributions accurately and

consistently is one of the fundamental goals of atomic physics. Helium

is of special importance because the electron-correlation contributions

can be calculated to almost arbitrary accuracy in a non-relativistic

approximation, and the inclusion of two-electron relativistic and QED

effects is simpler than for atoms having more electrons. Our

measurements, calculations, and critical analyses of the energy- level

data for helium contribute to a broad effort towards increased

understanding of this system.

ATOMIC BEAM SOURCE. An atomic beam apparatus designed for high

precision laser spectroscopy of rare gases in metastable states has been

constructed and tested. A flux of metastable helium atoms of about

10 1A /sec/sr has been obtained, corresponding to about 2 x 10 9 metastable

atoms per second at a collimation sufficient to reduce the residual

Doppler width to 10 MHz (0.0003 cm

-1

) in the visible region. We are currently readying our first laser observations of the beam source, a

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

measurement of the 2

1 S - 3

1 P transition. We plan a series of

measurements of the 2

1 S - n1 P transitions including highly excited

Rydberg states. Accurate wave number determinations for this series

should allow determination of the 2

X S ionization energy within an error

of a few parts in 109

. This will permit new tests of the most accurate

theoretical calculations in helium including two-electron QED effects

(C. Cromer and C. Sansonetti)

.

MEASUREMENTS IN HELIUM DISCHARGES. Additional precise measurements

of transitions not accessible with the metastable -beam apparatus are required to establish the energies of a number of low-lying helium

levels. We are currently observing some of these transitions using

Doppler-free laser methods in a low-pressure helium discharge. We have

obtained spectra of the 2

3 P-4 3 S, 2

: P - 41 D, and 21 P - 41 S transitions and are now attempting to make precise measurements of their wave numbers. As an outgrowth of our laser measurements in helium, we have also recorded emission spectra of low-pressure rf discharges in

helium by Fourier spectroscopy. These spectra have not yet been fully

analyzed, but they should provide precise measurements for some important

transitions not easily observed by laser methods. Most significant of

these are the 2

3 S - 23 P and 2

1 S - 2X P transitions which lie at 1.08

and 2.05 microns. These discharge measurements combined with the results

of our metastable beam work and previous laser measurements will provide

more accurate absolute ionization energies for virtually all low-lying

levels of helium (C. Sansonetti).

MEASUREMENTS WITH FABRY- PEROT WAVEMETER. In all of our laser

observations, high accuracy measurements of the dye laser wavelength are required to realize the full potential of the experiments. We have

continued to upgrade the Fabry-Perot wavemeter developed in our lab to

meet this requirement. Improvements in the optical system and laser beam

switch have increased the reliability of the instrument, reduced the

laser power required to about 0.5 mW, increased the measurement rate from

about 0.7 to 2 Hz, and reduced digitization errors in the computer

acquisition of the interference patterns. The instrument has been tested

in the green spectral region and has now been used successfully from 4700

to 7000 A. Throughout this region absolute accuracies of better than 3 MHz (10" 4 cm" 1 ) are routinely obtained (C. Sansonetti).

(d) Platinum Ultraviolet Reference Wavelengths

The spectrum of a platinum hollow-cathode discharge will be

used for on-board wavelength calibration of the High-Resolution

Spectrograph (HRS) for the Hubble Space Telescope. Since the absolute

wavelength accuracy of this instrument will be the limiting factor in a number of important planned observations, during the past several years

we measured the Pt spectrum from 1032 to 4100 A with our 10.7-m normal7
Division 531, Technical Activities (cont'd.)

incidence vacuum spectrograph. Some 3000 lines of Pt I and Pt II have

been determined with an average uncertainty of ±0.002 A. These

measurements have been incorporated into the calibration codes for the

HRS and are also now used in the reduction of data obtained with the

still active (10 years old) IUE satellite. We have in press a paper

giving accurate energy levels and wavelengths for the Pt II lines ( J

.

Reader, N. Acquista, C.J. Sansonetti; and R. Engleman, Jr. from Los

Alamos) . These measurements and our other Pt measurements will also be

used extensively for calibrations in high-resolution laboratory UV and

VUV spectroscopy.

During the past year we made new scans of the Pt spectrum using

photon-counting techniques for detection. Computer reduction of these scans will give accurate intensities for the lines. We plan to produce

an extensive atlas of the entire spectrum which will be highly useful for

HRS calibrations and for laboratory spectroscopy. A complete paper

giving all of our Pt wavelengths is also planned. ( J . Reader, N.

Acquista, C.J. Sansonetti, and J. Sansonetti).

(e) Atomic Energy Levels Data Center

This center critically evaluates and compiles data on energy

levels and spectral lines of atoms and atomic ions. We have just

completed a compilation of the energy levels for all 29 copper spectra

(Cu I - Cu XXIX) ( J . Sugar and A. Musgrove) . We also made substantial

progress on a similar compilation of energy levels for the sulfur spectra

(W.C. Martin, R. Zalubas , and A. Musgrove).

We are including critically evaluated wavelengths as part of a computerized data base on atomic spectra to be built up jointly by the

Atomic Energy Levels and Atomic Transition Probabilities Data Centers.

We have compiled the wavelengths and energy- level classifications for the

21 scandium spectra and have completed most of a similar compilation for

the silicon spectra (V. Kaufman and J. Sugar). Our compilations of

wavelengths and energy- levels classifications for all lines of Mo 5+

through Mo 41+ and Ni 5+ through Ni27+ were published recently. Similar

compilations for the spectra of all Fe and Cu ions stripped of 5 or more electrons have recently been completed or are near completion.

(J . Sugar, W.L. Wiese, and Japanese collaborators).

The fourth supplement to our Bibliography on Atomic Spectra , covering the literature from 1984 through 1987, is in press (A. Musgrove

and R. Zalubas) . A report on laboratory research on atomic spectra of

interest for astrophysics was prepared and published in the Trans. IAU

(W.C. Martin). We answer many individual requests for information on atomic spectroscopic data and supply lists of references of interest for

fusion-plasma research for the bibliographies issued semiannually by the

International Atomic Energy Agency.

8
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 collision

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

(1) A set of computer codes for relativistic atomic structure

and collision data has been developed, updated, and implemented on the

CYBER 205 at NIST. This work was carried out in collaboration with

J. P. Desclaux (French Atomic Energy Commission, Grenoble, France) and

P. Indelicato (Division 526 and Universite de Paris). New capabilities

are (i) Multiconfiguration Dirac-Fock (MCDF) wavefunction code in which

the Breit interaction is now calculated in the Coulomb gauge to be

consistent with QED procedures for higher order relativistic corrections;

(ii) Transition probability code in which MCDF wavefunctions derived

from the above code are used to calculate magnetic and electric multipole

transition probabilities; (iii) Relativistic distorted-wave Born cross section code in which cross sections for both excitation and ionization

of ions with arbitrary target configuration can be calculated; and

(iv) Angular momentum algebra code which carries out all angular momentum

algebra needed for the above codes

.

All codes are based on fully relativistic theory, include

correlation, and can be applied to neutral as well as highly charged

atoms, hydrogen through transuranium elements. Using these codes, a variety of atomic data were calculated ranging from energy levels to

ionization cross sections. As a result, two articles have been

published, four articles have been accepted for publication, and a few more are being prepared for publication. (M. A. Ali, Y.-K. Kim,

W.-J. Qian and E. B. Saloman, Div. 536)

(2) A systematic study of relativistic distorted-wave Born

cross sections for the 2s 2 1 S 0 - 2s2p 1,3 P 1 excitation of Be-like ions by

electron impact has been carried out. We found that the triplet

excitation, which is electric dipole (El) and spin forbidden, gradually

becomes El allowed due to intermediate coupling, while configuration

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

mixing in the ground state (2s z + 2p2

) remains important throughout the

periodic table, changing triplet excitation cross sections by as much as

30%. These cross sections are fitted with only four or five coefficients

for each transition for incident energies from the threshold to 10 keV.

The fitted coefficients, in turn, are expressed in terms of simple power

series in atomic number. In order to obtain reliable Z dependence, data

for a total of about 15 atoms in the periodic table are needed. About 80

coefficients thus determined reproduce cross sections for both the

triplet and singlet excitations from thresholds to 10 keV for all Be-like

ions in the periodic table. These coefficients provide a compact yet

accurate way to store and reproduce desired cross sections in various

modeling codes. (Y.-K. Kim and W.-J. Qian)

(3) In one-electron atoms at high Z, one of the largest

uncertainties in the energy levels has been the effect of higher-order

vacuum polarization corrections. These are corrections that are third or higher order in the external potential that go beyond the Uehling

approximation. To calculate this correction for bound electrons in highZ atoms, a coordinate space formulation of the problem that takes into

account the finite size of the nucleus has been developed in

collaboration with G. Soff of GSI, West Germany. Work being done on this

topic consists of a systematic application of the method to calculate

energy level corrections for various states over a wide range of nuclear

charge

.

In high-Z two-electron atoms, the dominant uncertainty in the

theoretical prediction for the energy levels is due to uncalculated

higher-order relativistic corrections in the Feynman diagram with two

photons exchanged between the bound electrons. The nonrelativistic limit

and first relativistic corrections for this diagram are known, but at

high Z, higher-order relativistic corrections are important, and a complete numerical calculation is needed. In a collaboration with

S. A. Blundell, W. R. Johnson, and J. Sapirstein of the University of

Notre Dame, such a calculation is being carried out for the ground state

of helium-like ions. We plan to extend this calculation to excited

states where a comparison with experiment can be made.

One of us initiated and participated as a coordinator for a program on "Relativistic, Quantum Electrodynamic and Weak Interaction

Effects in Atoms" that was held at the Institute for Theoretical Physics

at Santa Barbara (January- June , 1988). Over 30 experts on atomic theory

and quantum electrodynamics for many countries participated in the

program. (Y.-K. Kim also participated in this workshop, April-May, 1988).

One of the goals was to bring quantum electrodynamics to bear on the

practical problem of calculating the structure of atoms and ions having

more than one electron, especially atoms and ions with high nuclear

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

charge, where relativistic and QED effects are significant. Much of the

effort was devoted to developing a consistent formulation of a many-body

QED theory. Another goal of the program was to improve the theoretical

calculations of parity-violating amplitudes. Other problems such as spectra of Rydberg atoms, positronium, and positron production in heavyion collisions, which involve basic theory were also investigated. A

book containing lectures given in the program is being edited in

collaboration with W. R. Johnson of the University of Notre Dame and

J. Sucher of the University of Maryland. (P. J. Mohr)

(4) Our computation of the dielectronic recombination rates of

the ions isoelectronic to the elements of the second row of the periodic

table has been completed. A simple model has been used to analyze the

reduction of the effective rate of dielectronic recombination by the

thermal equilibrium of some of the bound, highly-excited final states

produced by the recombination with the plasma electrons in low to

moderate density plasmas. The computer codes have been upgraded to

include configuration interaction and intermediate coupling in the atomic

model. We participated in the IAEA Experts Meeting on Electron-Ion

Collision Processes for the Ions of Oxygen and Carbon in Fusion Plasmas

and the IAEA Meeting on Atomic Data for Fusion Plasmas. (L. J. Roszman)

(5) A method has been developed to calculate matrix elements

of the electric dipole operator between Russell Saunders (L-S coupled)

states, for which radial functions have been found via a Multiconfiguration Hartree-Fock (MCHF) procedure where all orbitals are

left free to vary. In the past, most of the core had to be frozen in

order to calculate the required angular factors under the assumption that

the core orbitals were orthonormal. The capability to allow completely

relaxed calculations for both the upper and lower states separately lets one account for the same degree of correlation in each state, thereby

taking full advantage of the MCHF method. As a first case, we have taken

the transitions ls2 2s 2 2p2 3p A D, 4 P, 4 S -> ls 2 2s 2 2p2 3s A P in neutral

nitrogen. Because the last term appears with a mixing coefficient of

about 0.35 in the calculation of the ls2 2s2p 4 4 P term of nitrogen, we have also calculated oscillator strengths for allowed transitions to that

state, which will make it possible to calculate lifetimes from data taken

in an experiment done by Zhu and Wiese of the division. (M. A. Suskin

and A. W. Weiss)

(6) Computer codes have been written for calculating dipole

transition probabilities, utilizing correlated wavefunct ions from the

Superposition of Configurations (SOC) programs. These codes are completely general in the sense that no assumptions are made concerning

the orthonomality of the orbital sets of the two terms of the transition.

Applications are currently being made to alkali and alkaline-earth

elements (and isoelectronic ions), Li, Na and Be (also Be+, Mg+, B+ and

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

C

2 +) . Wavefunctions are being computed including core correlation and

core-valence intershell correlation, as well as the usual valence

correlation corrections. (A. W. Weiss)

(7) The development of a computer code to generate spectral

line profiles for multi-electron ions in plasmas continues. Spectral

line profiles generated from this code have been used in the analysis of

laser-produced plasma experiments at the University of Rochester

Laboratory for Laser Energetics and the Princeton Plasma Physics

Laboratory. A joint effort is in progress with V. L. Jacobs (Naval

Research Laboratory) and C. F. Hooper, Jr. (University of Florida) on the

calculation of plasma-broadened line profiles of helium-like and lithiumlike satellites of hydrogenic and helium- like argon resonance lines,

including non-LTE populations and broadening due to autoionization,

radiative decay, electron collisions, and the plasma ion microfield.

Another collaboration is underway with T. D. Hahn and W. L. Wiese to

determine the ion broadening parameters of neutral carbon, nitrogen, and

argon spectral lines obtained in a wall-stabilized arc. (L. A. Woltz)

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

some for an extended period of time, some as regular weekly visitors.

M. A. Ali (Howard University) spends one day a week here during

the academic year working with Y.-K. Kim on relativistic atomic structure

calculations. He spent the entire summer of 1988 working with Kim.

W.-J. Qian (Liaoning University., Shenyang, China) has

completed a one-year visit with us, collaborating with Kim on the study

of relativistic distorted-wave Born cross sections of Be-like and Na-like

ions

.

L. A. Woltz (University of Florida) has been with us for the

past year collaborating with W. L. Wiese on the problems in the theory of

spectral line broadening.

(b) Data Center on Atomic Transition Probabilities

During 1988, a major accomplishment of the data center was the

completion, after 8 years of critical evaluation work, of two volumes

"Atomic Transition Probabilities- -Scandium through Manganese," and

"Atomic Transition Probabilities- - Iron through Nickel." These will

appear as hard bound supplements to the Journal of Physical and Chemical

Reference Data, about 500 pages each, with a total of about 18000

transitions. During the last year, data for V II, Mn I , Fe II, Ni I, and

Ni II were evaluated and compiled, which are included in the abovementioned publication and much proofreading was done.

12
Division 531, Technical Activities (cont'd.)

The literature on f-values is continually monitored, and an upto-date bibliography is maintained. Also, every six months, references

are provided for inclusion in the "International Bulletin on Atomic and

Molecular Data for Fusion," published by the International Atomic Energy

Agency. We prepared a mini-bibliography on all astrophysically important

literature references to be published in "Reports on Astronomy" by the

International Astronomical Union. ( J . R. Fuhr and W. L. Wiese)

The programming is complete to house the Bibliography on Atomic

Transition Probabilities within dBase III. The task of entering all past

citations remains, but once done, literature searches extending from the

present back to 1914 will be possible. Among the key fields are author,

title, species, isoelectronic sequence, and year of publication. The

bibliography can be indexed on up to seven fields at a time, and the

results given in printed form or as ASCII files on disc. (M. A. Suskin)

13
Division 531, Technical Activities (cont'd.)

Ill . Plasma Radiation Group

The plasma measurements program provides essential data and

measurement techniques for the analysis of plasmas, mainly for

temperature and density determinations, for VUV source radiometry, and

for VUV lasing schemes. The determination of collisional rate

coefficients is of critical importance in plasma modeling, especially for

VUV laser schemes and fusion- type plasmas. Determination of atomic

transition probabilities and plasma line broadening parameters have

provided many of the data needed for measurements of plasma densities and

temperatures of low temperature plasmas widely used for technological

applications, such as in semi conductor and materials processing,

spectrochemistry and plasma chemistry. Radiometric measurements of high

intensity VUV and X-ray sources have led to advances in source development for x-ray lithography. Our studies of population inversion

in the theta pinch have led to a better understanding of recombination

mechanisms for possible VUV laser schemes. Pulsed plasma source studies

have produced promising new VUV radiometric sources. Our portable

radiometric standards have been used for many spacecraft calibrations and

are in increasing demand for that purpose.

(a) Experimental Test of the Pauli Exclusion Principle (PEP)

New developments in quantum field theory indicate that the

Pauli principle is not necessarily absolutely rigorous, but that small

violations may be allowed. This very exciting and important result calls

for rigorous experimental testing of the exclusion principle. This

fundamental principle is responsible for the stability of atoms and

nuclei, for example, neutron stars. PEP follows from the

indistinguishability of identical particles. However, some atomic states

which satisfy indistinguishability are still forbidden by PEP. We have

been designing, and are embarking on, a series of experiments designed to

search for such states. The simplest and most accurately calculable of

such states are in helium. For each normal state of helium one can describe a state whose wavefunction exhibits a PEP- forbidden symmetry.

These PEP- forbidden states have slightly different energies than the

normal states, and they may be very precisely calculated. We plan first

to perform a relatively simple measurement with moderate (i.e., about 1 part in 10 10

) sensitivity to PEP violation. Subsequently, we plan to

perform a much more involved and powerful experiment which involves

enrichment of any PEP-violating ground states. Implications of an observed PEP-violation would be comparable to those associated with

parity violation, first observed at NBS . (D. E. Kelleher)

14
Division 531, Technical Activities (cont'd.)

(b) Collisional Rate Coefficients with the 50 kJ Theta Pinch

1. In the Li- like carbon atoms, population inversions have

been achieved between excited levels on a microsecond timescale for the

first time on a theta pinch. This is accomplished in a plasma generated

from various acetylene/hydrogen gas mixtures. Three-body recombination

was conceived to be the mechanism for these population inversions.

However, theoretical modeling using the measured electron temperature and

electron density profiles could not explain the observations. Charge

transfer from neutral hydrogen to He- like carbon at the plasma boundary

is being investigated as the mechanism for recombination.

Also, using a confocal mirror cavity, a gain factor of 12 was measured on the 2530 A of C IV line in experiments conducted in

collaboration with a group from Bell Laboratories. Experiments are continuing to further improve the gain..

2. One of the most successful soft X-ray lasers developed

recently is based on 3p to 3s transitions in Ne-like atoms present in

very dense laser-produced plasmas. However, several observed phenomena

have defied explanation to date, in spite of using sophisticated computer

models. For example, considerable gain has been observed for transitions

from J=2 sublevels and significantly lower gain has been observed for

transitions from the J=0 sublevel, contrary to expectations. A problem

with modeling has been that there is no experimental verification in

plasmas for the rates used in the computer codes. Of central importance

are absolute measurements of population densities and

collisional/radiative transition rates, supported by electron density and

electron temperature measurements, to calibrate the computer codes.

Experiments are underway to make such basic and quantitative measurements

on Ne-like argon and Ne-like silicon using the NBS theta pinch.

Also, under a recent grant from NATO, collaborative experiments

between the Institute of experimental Plasma Physics at the University of

Bochum, West Germany and NBS have just started to measure the excitation

rate of Ne-like argon and Li- like neon as another part of an effort for

theoretical code calibration. (R. Datla, R. C. Elton, J. R. Roberts)

(c) Tokamak Spectroscopy

In order to develop diagnostics for the measurements of

absolute densities of high Z impurities in tokamak plasmas, experiments

on Si-like Ni, Cu, Zn, Ge and Se are conducted on the TEXT tokamak, a national tokamak facility, operated by DOE at the University of Texas,

Austin. New forbidden lines have been identified and their intensities

measured absolutely. The absolute density of each ion can be measured if

the upper and lower levels in these transitions are statistically

15
Division 531, Technical Activities (cont'd.)

populated. Analysis of the data is continuing to develop a criterion for

statistical population along the isoelectronic sequence as a function of

electron density and forbidden transition probability. (R. Datla,

J. Roberts)

(d) Vacuum Ultraviolet Radiometrv with Plasmas

Quite a bit of work has been done during this past fiscal year

on the characterization of the Pt-Ne sealed hollow cathode lamp.

Procedures were developed and a goniometer was designed and constructed

for use in characterizing and calibrating these lamps. The following

particulars were determined for a sample lamp: warmup time, stability,

emission as a function of current, repeatability with ignition, spatial

characteristics, impurity lines, signal as a function of pitch and yaw,

and emission lifetime. A paper presenting these results is in

preparation

.

The data which we previously obtained in the calibration of the

hollow cathode lamps for the throughput test of the Hubble Space

Telescope were analyzed. A portion of the data was used in the paper

"Accurate Energy Levels for Singly Ionized Platinum (Pt II)," which is soon to be published in J. Opt. Soc. Am. B. The complete body of data

will be used in an atlas of lines emitted by these lamps which is in

preparation.

A project was initiated to develop a body of atomic branching

ratios for use in vacuum ultraviolet radiance calibrations. Analysis of

existing material has already resulted in collections of branching ratios

for the hydrogen, helium, lithium, and beryllium isoelectronic sequences.

It is planned that the results for these sequences will be published in

the near future and that these data will also be available on computer

disks. Work will continue on developing branching ratios for additional

isoelectronic sequences.

We are continuing to consult with scientists from NRL and NASAGoddard on the Solar Ultraviolet Spectral Irradiance Monitor (SUSIM) and

the Shuttle Solar Backscatter Ultraviolet (SSBUV) experiment. Other

notable activities during this year were our participation in the CORM

annual meeting held at NBS on May 18 and 19 and the publication of a condensed version of our calibration document which appeared in the NBS

Journal of Research. Efforts were continued to upgrade the accuracy and

reliability of our calibrations. Work during the past year included the

installation of some automated positioning equipment and computer

integration for better data acquisition and analysis. A linearity test was performed to insure accurate data for measurements covering a large

range in signal levels. Eight deuterium lamps were calibrated as secondary standards for our group and for the Radiometric Physics

16
Division 531, Technical Activities (cont'd.)

Division. In addition nine calibrations of various types were performed

for customers during the year. ( J . M. Bridges, J. Z. Klose)

(e) The transition probabilities of 29 prominent lines of neutral

nitrogen were measured in emission with a wall-stabilized high-current

arc and carefully analyzed. Our data are on average about 15-20% above

those of two earlier emission studies. The intensity contributions of

the extended line wings, which were not considered in the earlier

experiments, fully account for this difference. On the other hand, our results- -which are normalized against lifetime data--are still 8% lower

than the latest theoretical data. Deviations of similar magnitude and in

the same direction have also been observed in some other cases and seem

to point to a basic systematic discrepancy between advanced experiments

and theory (Q. Zhu, W. L. Wiese)

17
INVITED TALKS

Division 531, Atomic and Plasma Radiation

Datla, Raju U., "Recombination Into C IV in a 0-Pinch Plasma," University

of Maryland Colloquium, Baltimore, MD, February 2, 1988.

Kelleher, D. E., "The Paron Calutron: An Experimental Test of the Pauli

Exclusion Principle," JILA Colloquium, Boulder, CO, January 12, 1988.

Kelleher, D. E., "Field Effects on Autoionizing Resonances,"

International Line Shapes Conference, Torun, Poland, July 28, 1988.

Kim, Yong-Ki, "Relativistic Effects in Electron-Ion Collisions, Lawrence

Livermore National Laboratory, December 14, 1987.

Kim, Yong-Ki, "Relativistic Distorted-Wave Cross Sections for ElectronIon Collisions," Lawrence Livermore National Laboratory, June 21, 1987.

Klose , Jules Z., "Radiance of a Pt/Cr-Ne Hollow Cathode Spectral Line

Source," Council for Optical Radiation Measurements, NBS , Gaithersburg,

MD, May 18, 1988.

Martin, William C., Atomic Spectroscopic Data of Astrophysical Interest,"

Scientific Session of Commission 14, General Assembly of International

Astronomical Union, Baltimore, MD, August 4, 1988.

Mohr, Peter J., "Structure of High-Z One- and Two-Electron Atoms," Atomic

Physics Seminar, University of Notre Dame, South Bend, IN,

October 15, 1987.

Mohr, Peter J., "Quantum Electrodynamics Tests in High-Z Atoms," Physics

Dept. Colloquium, University of South Carolina, Columbia, SC,

November 19, 1987.

Mohr, Peter J., "Quantum Electrodynamics Tests in High-Z Atoms," Atomic

Physics Seminar, University of Southern California, February 24, 1988.

Mohr, Peter J., "Quantum Electrodynamics of Highly- Ionized Atoms," NATO

Advanced Study Institute: Atomic Physics of Highly- Ionized Atoms,

Cargese, Corsica, June, 1988.

Mohr, Peter J., "Quantum Electrodynamics of High-Z Few-Electron Atoms," V

Division Seminar, Lawrence Livermore National Laboratory,

August 23, 1988.

Reader, Joseph, "Spectra of Highly- Ionized Atoms," Symposium on Innovative Science and Technology, Los Angeles, CA, January 14, 1988.

18
Division 531, Invited Talks (cont'd.)

Sugar, Jack, "Spectroscopy at NBS Related to Fusion Energy Research,"

University of Arizona, Tucson, AZ , November, 1987.

Sugar, Jack, "The Tokamak as a Spectroscopic Light Source," Japan Atomic

Energy Research Institute, Tokai-mura, Japan, March, 1988.

Wiese, W. L. , "Spectroscopic Data Compilations at NBS," Meeting of the

International Network of Atomic Data Centers, Oak Ridge, TN

,

November 9, 1987.

Wiese, W. L. , "The Spectroscopic Data Base for Carbon and Oxygen,"

Specialists Meeting, International Atomic Energy Agency, Vienna, Austria,

May 10, 1988.

Wiese, W. L. , "Accuracy of Atomic Transition Probabilities," Symposium on

the Accuracy of Stellar Abundance Determinations, 20th General Assembly

of the International Astronomical Union, Baltimore, MD , August 4, 1988.

Wiese, W. L. , "Towards More Reliable Atomic Transition Probabilities,"

Physics Colloquium, University of Zagreb, Yugoslavia, September 22, 1988.

Wiese, W. L. , "A Unified Set of Atomic Transition Probabilities for

Argon," Institute of Physics, Belgrade, Yugoslavia, September 27, 1988.

19
PUBLICATIONS

Division 531, Atomic and Plasma Radiation

Datla, R. U. , Roberts, J. R. , Silfvast, W. T. , and Wood, II, 0. R.

,

Population inversions of C IV in a recombining theta-pinch plasma, Opt.

Lett. , 12, 675 (1987)

.

Datla, R. , Roberts, J. R., Durst, R. D., Hodge, W. L. , Klepper, C. C.,

Rowan, W. L. , and Mann, J. B., Measurement of excitation rate

coefficients for Al-like ions: Fe XIV, Ni XVI and Cu XVII, Phys . Rev. A,

36, 5448 (1987).

Datla, R. and Kunze , H.-J., Electron impact excitation and recombination

into excited states of lithium-like ions, Phys. Rev. A, 37, 4614 (1988).

Ekberg, J. 0, Feldman, U., and Reader, J., 3p6 3d8 - 3p

5 3d9 transitions in

ironlike ions from Ru18+ to Gd38+

, J. Opt. Soc . Am. B 5, 1275 (1988).

Feldman, U, and Reader, J., Scheme for a 60 nm laser based on photopumping of a high level of Mo 6+ by a spectral line of Mo 11+ [in

press ]

.

Fuhr , J. R. , Martin, G. A., and Wiese, W. L. , Atomic Transition

Probabilities- -Iron through Nickel, J. Phys. Chem. Ref. Data 17 . Suppl. 4

(1988)

.

Fuhr, Jeffrey R., Critical Evaluation of Atomic Transition Probability

Data, in Elemental Abundance Analyses , edited by S. J. Adelman, and

T. Lanz , (Institut d'Astronomie de l'Universite de Lausanne, CH-1290

Chavannes-des Bois, Switzerland, April, 1988), p. 173.

Iglesias, L. , Cabeza, I., Rico, F. and Kaufman, V., Fundamental

Configurations of Doubly- ionized Molybdenum (Mo III), Phys. Scripta 37 . 855 (1988).

Jones, D. W. , and Wiese, W. L. , Atomic Transition Probabilities for the

Ar I 4s-5p Transition Array, Phys. Rev. A [in press],

Kaufman, V., and Sugar, J., In I Isoelectronic Sequence: Wavelengths and

Energy Levels for Xe VI Through La IX, J. Opt. Soc. Am. B 4, 1924 (1987).

Kaufman, V., and Sugar, J., Wavelengths and energy level classifications

of scandium spectra for all stages of ionization, J. Phys. Chem. Ref.

Data [ in press ]

.

Kaufman, V., Sugar J., and Rowan, W. L. , Spectra of copperlike and

zinclike xenon: Xe XXV and Xe XXVI, J. Opt. Soc. Am. B 5, 1273 (1988).

20
Division 531, Publications (cont'd.)

Kaufman, V., Sugar, J., and Rowan, W. L. , Wavelengths and energy levels

of the K I isoelectronic sequence from Cu through Mo, J. Opt. Soc. Am.

[ in press ]

.

Kaufman, V., Sugar J., and Joshi, Y. N., Wavelengths and energy levels of

I V and I VI, J. Opt. Soc. Am. B 5, 619 (1988).

Kaufman, V., and Sugar, J., Revisions in La XI and La XII based on comparison with scaled Hartree-Fock calculations, J. Opt. Soc. Am. B 5,

730, (1988).

Kim, Y.-K., Sugar, J., Kaufman, V., and Ali, M. A., QED corrections to

spin-orbit splitting in the ground state of Al-like ions, J. Opt. Soc.

Am . [in press ]

.

Kim, Y.-K., and Desclaux, J. P., Relativistic effects in electron-atom

collisions, Phys . Scr. .36, 796 (1987).

Kim, Yong-Ki, and Desclaux, Jean-Paul, Incident-energy dependence of

electron-ion collision cross sections, Phys. Rev. A 3.8, 1805 (1988).

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

effects in the 2s3p configuration of Be-like ions, J. Opt. Soc. Am. B [in

press ]

.

Kim, Y.-K., and Ali, M. A., Electric Quadrupole and Magnetic Dipole

Transition Probabilities in the Potassium Isoelectronic Sequence [in

press ]

.

Klose, J. Z., and Bridges, J. M. , Radiance of a Pt/Cr-Ne Hollow Cathode

Spectral Line Source, Appl. Opt. 26., 5202 (1987).

Klose, Jules Z., Bridges, J. Mervin, and Ott, William R. , Radiometric

Calibrations of Portable Sources in the Vacuum Ultraviolet, J. Res. Natl.

Bur. Stand. (U.S.) 93, 21 (1988).

Litzen, U. , and Reader J., Spectra and energy levels of ions in the zinc

isoelectronic sequence from Rb VIII to Mo XIII, Phys. Rev. A 36 , 5159

(1987) .

Litzen, U., and Reader, J., Spectra and energy levels of the galliumlike

ions Rb VII - Mo II, Phys. Scr. [in press].

Martin, G. A., Fuhr, J. R. , and Wiese, W. L. , Atomic Transition

Probabilities -- Scandium through Manganese, J. Phys. Chem. Ref. Data 1

7

. Suppl . 3 (1988).

21
Division 531, Publications (cont'd.)

Martin, W. C., Atomic spectra and wavelength standards, Trans. Inti.

Astr. Union 20A . Ill (1988).

Mohr, Peter J., Feynman Diagrams, in McGraw-Hill Encyclopedia of Science

and Technology . 6th Ed. (McGraw-Hill, New York, 1987), p. 92.

Mohr, Peter J., Status of Precision QED in Light and Heavy Atoms, in

Physics of Strong Fields , ed. by W. Greiner (Plenum, New York, 1987), p.

17.).

Mohr, Peter J., Structure of High-Z One- and Two-Electron Atoms, Nucl.

Instrum. & Methods, B 3.1, 1 (1988).

Morley, P. D., and Sugar, J., Exploding foil photoionization X-ray laser,

Phys. Rev. A 38, 3139 (1988).

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

Spectra, January 1984 through December 1987, NBS Spec. Publ. 363, Suppl.

4 [ in press ]

.

Oza, Dipak H., Exchange asymmetry in elastic scattering of electrons by

sodium atoms, Phys. Rev. A 3_7, 2721 (1988).

Oza, Dipak H., Greene, Ronald L. , and Kelleher, Daniel E., Dependence of

the half widths of plasma-broadened hydrogen lines on reduced mass,

temperature, and density, Phys. Rev. A ]38, 2544 (1988).

Oza, Dipak H., Greene, Ronald L. and Kelleher, Daniel E., Collisional

broadening of the Balmer-a transition of H and He+ in plasmas, Phys. Rev.

A 37, 531 (1988)

.

Oza, D. H., Benoit-Cattin, P., Bordenave -Montesquieu, A., Boudjema, M.

,

and Gleizes, A., Autoionisation of N

5+ for n'=3-10: experiment and

theory, J. Phys. B: At. Mol. Opt. Phys 2_1 L131 (1988).

Reader, J., Sugar, J., and Kaufman, V., Recent Progress on Spectral Data

for X-Ray Lasers at the National Bureau of Standards, IEEE Transactions

on Plasma Science [in press].

Reader, J., Acquista, N. , Sansonetti, C., and Engleman, R., Accurate

Energy Levels for Singly Ionized Platinum (Pt II), J. Opt. Soc. Am. B [in

press ]

.

Reader, J., Sugar, J. and Kaufman, V., Spectra of Highly- Ionized Atoms;

SPIE, Short and Ultrashort Wavelength Lasers, 875 . 66 (1988).

22
Division 531, Publications (cont'd.)

Reader, J., and Corliss, C. H., Line Spectra of the Elements, Handbook of

Chemistry and Physics , 68th edition, CRC Press, E201 (1987).

Roginsky, D. V. I, and Weiss, A. W., Calculation of tighter error bounds

for theoretical atomic-oscillator strengths, Phys . Rev. A 3_8, 1760

(1988) .

Saloman, E. B., and Kim, Y. -K. , Effects of Configuration Mixing in Ml and

E2 Transitions Between Ground-State Terms of Sulfurlike Ions, Phys. Rev.

A 38, 577 (1988) .

Sansonetti, Craig J., Andrew, K. L. , and Wyart , J.-F., Spectrum and

energy levels of singly ionized cesium. II. Interpretation of fine and

hyperfine structures, J. Opt. Soc. Am. B [in press],

Shirai, T., Nakai, Y. , Ozawa, K. , Ishii, K. , Sugar J., and Mori, K.

,

Spectral data for molybdenum ions, Mo V-Mo XLII, J. Phys. Chem. Ref. Data

16, 327 (1988).

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

,

Spectral Data and Grotrian Diagrams for Highly Ionized Nickel, Ni INi XXVIII, At. Data Nucl. Data Tables 37, 235 (1987).

Sims, James S. and Martin, W. C., Variational calculations for 4 He I: improved energies for singlet and triplet n D and n F levels (n=3-8)

Phys. Rev. A 37, 2259 (1988).

Sugar, J. and Kaufman, V., Additions and Revisions to the Levels of the

Mg-like Cu XVIII and Zn XIX, J. Opt. Soc. Am. B 4, 2010 (1987).

Sugar, J., Kaufman, V., and Rowan, W. L. , Resonance Transitions in the

Mg I and Ar I Isoelectronic Sequences from Cu thru Mo, J. Opt. Soc. Am. B

4, 1927 (1987).

Sugar, J., Kaufman, V., and Rowan, W. L. , Spectra of Se XVI to Se XXIV

observed in a tokamak plasma, J. Opt. Soc. Am. B 5, 236.

Sugar, J., NBS Atomic Data Centers: Review of recent and imminent

publications, Spectrochim. Acta, 43B 21 (1988).

Sugar J., and Musgrove, A., Energy levels of Molybdenum I through

Mo XLII, J. Phys. Chem. Ref. Data L7> 155 (1988).

Sugar, J., Kaufman, V., and Rowan, W. L. , Al-like spectra of copper

through molybdenum, J. Opt. Soc. Am. [in press].

23
Division 531, Publications (cont'd.)

Traebert, E., Heckmann, P. H., and Wiese, W. L. , Wavelength and lifetime

measurements on intercombination transitions in 12- to 14- electron ions

of Zn, Z. Phys . D--Atoms, Molecules and Clusters 8, 209 (1988).

Wiese, W. L. , On the critical assessment of atomic spectroscopy data, in

Report of Workshop on the Assessment of Atomic Data . (The Queen's Univ.

of Belfast), 1987.

Wiese, W. L. , Atomic Transition Probabilities, in Reports on Astronomy . Vol. XX A (Reidel Publ. Co., Dordrecht, Holland), 1988.

Wiese, W. L. , The Atomic Transition Probabilities of Argon--a continuing

challenge to plasma spectroscopy, J. Quant. Spectrosc. Radiat. Transf.

[ in press ]

.

24
PUBLICATIONS IN PREPARATION

Division 531, Atomic and Plasma Radiation

Brewer, L. R. , Buchinger, F. , Ligare , M. , and Kelleher, D. E., Resonanceenhanced multiphoton ionization of atomic hydrogen (in preparation).

Cromer, C. L. and He, M. , Double -Resonance Optogalvanic Spectroscopy of

Ne in a New Ultra-Low Pressure Discharge (in preparation).

Cooper, J. W. , Clark, C. W. , Cromer, C. L. , Lucatorto, T. B.,

Sonntag , B. F. , Kennedy, E. T., Costello, J. T., Junwen, C., and

Tomkins, F. S., Autoionizing Resonances in Mn, Mn+ and Cr 3p Subshell

Absorption (submitted to Phys . Rev. Lett.).

Hahn, T., and Wiese, W. L. , Transition probability ratios between 4s-5p

and 4s-4p lines of neutral argon (to be submitted to Phys. Rev. A).

Kelleher, D. E., An Overview of the Ion Dynamic Effect in Line

Broadening, and a Generalization of the Unified Theory, to be published

by Springer Verlag.

Klose , J. Z. and Wiese, W. L. , Branching Ratio Technique as Applied to

Vacuum UV Radiance Calibration: Extensions and an Expanded Data Set (in

preparation)

.

Klose, J. Z., Brightness Comparison of Several Platinum Hollow Cathode

Lamps (in preparation).

Litzen, U., and Reader, J., 4s 2 4p2 - 4s4p3 transition array and energy

levels of the germanium- like ions Rb VI - Mo XI (in preparation).

Mohr, Peter J., Quantum Electrodynamics Calculations, in Spectrum of

Atomic Hydrogen: Advances , ed. by G. W. Series (submitted to World

Scientific, Singapore).

Mohr, Peter J., and Soff, G., Vacuum Polarization in a Strong External

Field, (submitted to Phys. Rev. A).

Mohr, Peter J., and Sucher, J., Level Shifts in Bound-State Quantum

Electrodynamics, in Relativistic. Quantum Electrodynamic . and Weak

Interaction Effects in Atoms , ed. by W. R. Johnson, AIP Conference

Proceedings, No. XXX (in preparation).

Mohr, Peter J., Blundell, S. A., Johnson, W. R. , and Sapirstein, J.,

Evaluation of Two-Photon Exchange Graphs for the Helium Isoelectronic

Sequence (in preparation).

25
Division 531, Publications in Preparation (cont'd.)

Mohr, Peter J., Quantum Electrodynamics of High-Z Few-Electron Atoms, in

Atomic Physics of Highly- Ionized Atoms , ed. by R. Marrus (Plenum, New

York) , in preparation.

Mohr, Peter J. and Soff, G., Influence of Higher-Order Vacuum

Polarization Corrections in Hydrogen-Like Uranium (in preparation).

Oza, Dipak H., Exchange Asymmetry in Elastic Scattering of Electrons by

Sodium Atoms, submitted to Phys . Rev. A.

Qian, W.-J., Kim, Y.-K., and Desclaux, J.-P., Relativistic distorted-wave

cross sections for electron impact excitations of beryllium- like ions,

submitted to Phys. Rev. A.

Reader, J., Acquista, N., Sansonetti, C. J., and Sansonetti, J.,

Wavelengths of Platinum Hollow-Cathode Discharge (in preparation).

Roszman, L. J., Dielectronic recombination rates for 0

2+ and 05+

including some density effects (in preparation).

Roszman, L. J., The influence of metastable states and plasma density

upon dielectronic recombination in low to moderate density plasmas

(submitted to Phys. Rev. A).

Roszman, L. J., Revised dielectronic-recombination rate coefficients for

the fluorine isoelectronic sequence (in preparation).

Sansonetti, C. J., Fabry-Perot Wavemeter for Rapid Precise Laser

Wavelength Measurements, (in preparation).

Sansonetti, C. J., Precise Laser Wavelength Measurements: What Can We

Learn from Classical Spectroscopy? (in preparation).

Shirai, T. , Nakai, Y. , Ozawa, K. , Ishii, K. , Sugar, J. , and Mori, K.

,

Spectral Data for Copper Ions, Cu VI - Cu XXIX (in preparation.)

Shirai, T., Funatake , Y. , Mori, K. , Sugar, J., Wiese, W. L. , and

Nakai, Y. , Spectral Data and Grotrian Diagrams for Highly Ionized Iron,

Fe VIII-Fe XXVI (in preparation).

Shirai, T., Mori, K. , Sugar, J., Wiese, W. L. , and Nakai, Y. , Spectral

Data and Grotrian Diagrams for Highly Ionized Chromium, Cr Vl-Cr XXIV (in

preparation)

.

Sugar, J., Kaufman, V., and Indelicato, P., Analysis of Magnesiumlike

Spectra from Cu XVIII to Mo XXXI, (in preparation).

25
Division 531, Publications in Preparation (cont'd.)

Sugar J., and Musgrove, A., Energy Levels of Copper, Cu I through Cu

XXIX, J. Phys . Chem. Ref. Data (in preparation).

Veza, D., and Sansonetti, C. J., Ionization of Lithium Vapor by CU

Quasiresonant Laser Light, (in preparation).

Wiese, W. L. , Brault, J. W. , Danzmann, K. , Helbig, V., and Kock, M. , A

Unified Set of Atomic Transition Probabilities for Neutral Argon,

submitted to Phys. Rev. A.

Wiese, W. L. and Robey, A. (Editors), Spectroscopic Data Tables for Ti,

Cr, and Ni, Vol. 7 of Atomic-Data-for-Fusion Series, to be published by

Oak Ridge National Laboratory.

Wiese, W. L. , The Spectroscopic Data Base for Carbon and Oxygen, (to be

submitted to Phys. Scripta)

.

Wiese, W. L. , and Fuhr, J. R. , The accuracy of atomic transition

probabilities (to be submitted to Lecture Notes of Physics, Springer

Verlag)

.

Woltz, L. A., and Hooper, C. F. , Calculation of spectral line profiles of

multi-electron emitters in plasmas (submitted to Phys. Rev. A).

Zhu, Q. , Bridges, J. M. , Hahn, T., and Wiese, W. L. , Oscillator Strength

Measurements for Prominent Spectral Lines of Atomic Nitrogen (to be

submitted to Phys. Rev. A).

27
TECHNICAL AND PROFESSIONAL COMMITTEE PARTICIPATION AND LEADERSHIP

Division 531, Atomic and Plasma Radiation

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.

William C. Martin

Chairman, Working Group on Atomic Spectra, International

Astronomical Union.

Member, IAEA Network of Atomic Data Centers for Fusion.

Member, Optical Society of America, W. F. Meggers Award Committee

Peter J. Mohr

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

Spectroscopy

.

Member of Program Committee, Division of Atomic, Molecular, and

Optical Physics, American Physical Society.

Member of International Advisory Committee, conference series on Physics and Highly- Ionized Atoms.

James R. Roberts

Member of TEXT Users Organization.

Jack Sugar

Chairman, OSA Fellows and Honorary Members Committee.

Mark Suskin

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

Spectroscopy

.

28
Division 531, Technical and Professional Committee Participation and

Leadership (cont'd.)

Wolfgang L. Wiese

Member of Organizing Committee, International Astronomical Union,

Commission on Fundamental Spectroscopic Data.

Chairman, Working Group on Atomic Transition Probabilities,

International Astronomical Union.

Vice President, Commission on Fundamental Spectroscopic Data,

International Astronomical Union.

Member, IAEA network of Atomic Data Centers for Fusion.

29
iMAJOR 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.

Periodically, special reports are prepared for particular user

groups. Thus, W. C. Martin and W. L. Wiese have written

updates on atomic data of interest for the as trophysical

community for the Transactions of the International Union

(IAU) , covering the three year period September 1984 through

August 1987, and give review reports at the General Assemblies

of the International Astronomical Union. J. R. Fuhr and

A. Robey submit literature reference lists every six months to

the International Atomic Energy Agency (IAEA) for inclusion in

the IAEA semiannual Bulletin of "Atomic Data for Fusion."

2. J. M. Bridges consulted with NASA-Goddard scientists on tests

and calibrations to be performed for the Shuttle Solar

Backscatter Ultraviolet experiment.

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

Lawrence Livermore Laboratory on x-ray laser development.

4. J. Z. Klose and J. M. Bridges consulted with NRL scientists on calibration work to be performed for the Solar Ultraviolet

Spectral Irradiance Monitor.

5. J. Z. Klose continues to consult with scientists at the Space

Telescope Science Institute on calibration work for the Hubble

Space Telescope.

6. W. C. Martin and J. Reader consult and advise NASA scientists

and other astronomers on standard wavelengths for calibration

of the High-Resolution Spectrograph for the Space Telescope.

7. Peter J. Mohr served as coordinator for the program on Relativistic, Quantum Electrodynamic, and Weak Interaction

Effects in Atoms, January - June, 1988 at the Institute for

Theoretical Physics, University of California, Santa Barbara.

30
Division 531, Major Consulting and Advisory Services (cont'd.)

8. J. Reader continues to consult with members of the x-ray laser

program at Lawrence Livermore National Laboratory about the

spectra of highly ionized atoms in laser-produced plasmas and

the wavelength calibration of such spectra.

9. J. R. Roberts continues to serve as a member of the TEXT Users

Organization (TUO) . TEXT stands for Texas Experimental Tokamak

and is a national plasma users facility.

10. J. R. Roberts continues to consult with members of Bell Labs on population inversion experiments in C

+

3

on the NBS theta pinch.

11. J. R. Roberts and R. U. Datla consulted with staff of the Naval

Research Laboratory on population inversion experiments in

Ar VIII and IX and recombination mechanisms in UV lasers.

12. L. J. Roszman continues to advise and consult with the Impurity

Transport Modeling Group of the Princeton Plasma Physics

Laboratory on electron-ion collision processes and other atomic

data as well as the modeling of low density plasmas.

13. J. Sugar and W. L. Wiese consulted and advised the Japan Atomic

Energy Research Institute (JAERI) on the compilation of

spectral lines.

14. J. Sugar consulted with KMS Fusion scientists on the

development of x-ray lasers.

31
JOURNAL EDITORSHIPS

Division 531, Atomic and Plasma Radiation

W. C. Martin, Co-Feature Editor for Journal of the Optical Society of

America B, Special Issue for October 1988, "Atomic Spectroscopy in the

Twentieth Century."

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

Radiative Transfer.

W. L. Wiese, Editor, Atomic Transition Probabilities, Handbook of

Chemistry and Physics . CRC Press.

32
TRIPS SPONSORED BY OTHERS

Division 531, Atomic and Plasma Radiation

Yong-Ki Kim visited the Centre d' Etudes Nuceaires de Grenoble, France, to

collaborate with J. P. Desclaux on relativistic atomic collision codes,

October-November , 1987, paid by a research grant from NATO.

Yong-Ki Kim participated in the Workshop on QED and Relativistic Effects

in Atoms, Santa Barbara, CA, April-May, 1988.

Yong-Ki Kim was invited to attend the Workshop on Relativistic Effects in

Atomic Collisions, Lawrence Livermore National Laboratory, Berkeley, CA,

June 20, 1988.

Peter J. Mohr was invited to the University of Notre Dame, South Bend, IN

for an Atomic Physics Seminar, October 15, 1987.

Peter J. Mohr was invited to the University of South Carolina, Columbia,

SC for a Physics Department Colloquium, November 19, 1987.

Peter J. Mohr was invited to Santa Barbara, CA to serve as coordinator

for the program on Relativistic, Quantum Electrodynamic, and Weak

Interaction Effects in Atoms, January- June , 1988.

Peter J. Mohr was invited to the University of Southern California,

February 24, 1988 to participate in an Atomic Physics Seminar.

Peter J. Mohr was invited to Cargese , Corsica to participate in the NATO

Advanced Study Institute: Atomic Physics of Highly- Ionized Atoms, June,

1988.

Peter J. Mohr was invited to Paris, France to participate in the Eleventh

International Conference on Atomic Physics (ICAP XI), July 4-8, 1988.

Peter J. Mohr was invited to Lawrence Livermore National Laboratory,

Berkeley, CA, to give an invited talk August 23, 1988.

Larry J. Roszman was invited to Lawrence Livermore National Laboratory,

Berkeley, CA to attend a workshop on Electron-Ion Collision Theory and

Computations, June 20-22, 1988.

Jack Sugar was invited to and gave a lecture at the University of Arizona

in November, 1987.

33
Division 531, Tripte Sponsored by Others (cont'd.)

Jack Sugar visited Japan Atomic Energy Research Institute (JAERI) in

Tokai-mura, Japan under the U.S. -Japan fusion cooperation program to work

with Japanese collaborators on atomic data compilations in March, 1988.

W. L. Wiese will travel to Yugoslavia and Poland September-October , 1988.

He will visit the Universities of Zagreb, Belgrade and Krakow to discuss

ongoing collaborative projects under cooperative NIST S & T programs and

give seminar talks. All expenses paid by U . S

. -Yugoslav Joint Board and

Marie Curie/Sklodowska Foundation.

34
CALIBRATION SERVICES PERFORMED

Division 531, Atomic and Plasma Radiation

No . of

Tvoe of Service Customer SP 250 Tests Income

Radiometer IBM 40040S 1 $ 2.1k

Radiometer Perkin Elmer 40040S 1 2.6k

Argon Mini-Arc Goddard Space Flight

Center

Contract 4 10.4k

Argon Mini-Arc ETH, Zurich 40040S 1 2.3k

Deuterium Lamp Sandia Corp. 40030S 1 1.5k

Deuterium Lamp Univ. of Colorado 40030S 1 1.5k
SPONSORED SEMINARS AND COLLOQUIA

Division 531, Atomic & Piasma Radiation

Ian P. Grant, Oxford University, Oxford England, "QED for Atoms and

Molecules Using Basis Sets," October 13, 1987.

J. Bayfield, University of Pittsburgh, "Excited Hydrogen Atoms in Strong

Microwave Fields: Search for Chaos in Quantum Mechanics,"

October 14, 1987.

Hans Schlueter, Ruhr University, Bochum, West Germany, "Spectroscopic

Studies on RF Field- Strengths in Plasmas," October 27, 1987.

Julian Coutts , JILA, University of Colorado, Boulder, CO, "CollisionInduced Absorption in Calcium- -Rare Gas Collision Complexes,"

November 6, 1987.

Elisabeth Kallne, JET Joint Undertaking, Oxford, England, "X-Ray

Spectroscopy at the Large Tokamaks , " November 9, 1987.

Lawrence Woltz, University of Florida, Gainesville, FL, "Spectral Line

Profiles of Multi - Electron Emitters in Plasmas," December 1, 1987.

W. L. Wiese, NIST, Atomic & Plasma Radiation Division, "The Transition

Probabilities of Argon- -A Challenge for Spectroscopy," December 15, 1987.

Ray Elton, Naval Research Laboratory, Washington, DC, "Soft X-Ray Lasing

at NRL in Neon-Like Plasmas," January 5, 1988.

Sveneric Johansson, University of Lund, Lund, Sweden, "The Unpredictable

Stars: On Anticorrelation Between Laboratory and Stellar Spectra,"

J anuary 12, 1988.

Verne Jacobs, Naval Research Laboratory, Washington, DC, "Autoionization

Phenomena in High-Temperature Plasma Processes," February 2, 1988.

Victor Kaufman, NIST, Atomic & Plasma Radiation Division, "Analyses of

Tokamak and Other Spectra Using the Methods of Isoelectronic Sequences,"

February 16, 1988.

John Gillaspy, Harvard University, Cambridge, MA, "Quest for BoseEinstein Condensation in Spin- Polarized Hydrogen," March 1, 1988.

Ulf Litzen, University of Lund, Lund, Sweden, "Spatially Resolved LaserProduced Spectra of Highly Ionized Transition Metal Elements,"

March 8, 1988.

36
Division 531, Sponsored Seminars and Colloquia (cont'd.)

Manfred Kock, University of Hannover, Hannover, West Germany, "Plasma

Spectroscopy at the University of Hannover- -Hollow Cathode Lamps,

Branching Ratios, and Photoionization Cross Sections," March 18, 1988.

Ingvar Lindgren, Chalmers University of Technology, Goteborg, Sweden,

"Towards a Relativistic Many-Body Procedure for Atomic Systems, March 25,

1988.

C. C. J. Roothaan, University of Chicago, Chicago, IL, "General Scheme

for Fractional Parentage in Atoms," April 21, 1988.

Steven Rolston, Lyman Laboratory, Harvard University, Cambridge, MA,

"Antiprotons and Antihydrogen," May 19, 1988.

John Hoffnagle, IBM Almaden Research Center, San Jose, CA, "Chaotic

Motion of Ions in a Pauli Trap," May 31, 1988.

M. Klapisch, Hebrew University, Jerusalem, Israel, "Atomic Processes in

Hot Plasmas-Model Computations with HUJI Code, August 15, 1988.

Robert Hilborn, Amherst College, Amherst, MA, "Spectroscopic Tests of the

Symmetrization Postulate for Bosons," September 8, 1988.

37

TECHNICAL ACTIVITIES

Division 533, Radiation Physics

The Radiation Physics Division focuses on measurement programs

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

radiation in the energy range from about 5 eV (250 nm) to 1 keV (1.3 ran) .

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 NIST synchrotron radiation

facility and a detector calibration facility based upon wellcharacterized 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 spinpolarized electron sources and detectors are used to determine

fundamental atomic scattering properties and to measure surface

magnetism. A scanning tunneling microscope is being used 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

relate the behavior of condensed matter systems to their fundamental

atomic and molecular properties.

The Division has two major research facilities: a dedicated

synchrotron ultraviolet radiation facility (SURF-II) , and a polarized

electron research facility.

SURF-II is a dedicated synchrotron radiation facility, consisting of

a 300 MeV electron storage ring, a 10 MeV microtron injector, and

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

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

ultraviolet, and into the soft x-ray region. 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.

39
Division 533, Technical Activities (cont'd)

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

NIST 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 helps to fill 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. It is available for

collaborative research by NIST 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 ^A, 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 parameters can be

used to determine surface structure or study surface magnetic phenomena

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

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

exchange interactions in electron scattering and to completely describe

the selected collision process.

In relatively new research directions, several innovative electron

measurement techniques pioneered at NIST are being further developed in

cooperative programs with industry to study the atomic and magnetic

microstructure of advanced materials. Magnetic microstructure can be

measured with a spatial resolution approaching 100 Angstroms (0.01

microns) by a technique called Scanning Electron Microscopy with

Polarization Analysis (SEMPA) . An ultra-high vacuum scanning tunneling

microscope has also been constructed to investigate, on an atomic scale,

the nucleation and growth of thin films on clean metallic and

semiconductor surfaces.

Division staff are also collaborating on two projects at the

National Synchrotron Light (NSLS) facility at Brookhaven. The first

involves radiation probing of exotic materials with soft x-rays. With

colleagues from the U. of Tennessee and Oak Ridge National Labs, we are studying core-hole excitation and soft x-ray fluorescence in solid

materials of fundamental and industrial significance such as GaAs, quasicrystals, and high Tc superconductors. This is being done using an IR100 award-winning, high sensitivity, soft x-ray emission spectrometer

with an efficiency 1000 to 10,000 higher than conventional spectrometers

in the energy range 20 eV to 1 keV.

40
Division 533, Technical Activities (cont'd)

In the second project, Division staff are part of a consortium of 11

principal investigators from 8 major laboratories representing industry,

universities, and government. This "Materials Research Group", funded

principally by NSF, is studying surface magnetism using spin polarized

photoemission techniques on materials prepared with molecular beam

epitaxy methods. This work is being done on an undulator beamline at

NSLS

.

As can be seen in the following sections, the Division staff have

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 NIST and with universities, industry, and other government

agencies. Some highlights of the past year include:

1. A new, greatly improved SEMPA instrument for measuring magnetic

microstructure with greater speed, sensitivity, and reliability is

operational. The development was featured in several corporate

magazines, and a major new collaboration was initiated with PerkinElmer

.

2. Our scanning tunneling microscope has been used to measure unusual

"atomic chains" formed with a low coverage of Cs adsorbate on GaAs(llO). The vertical resolution of the ultra-low noise

instrument is about .01 Angstroms.

3. SURF-II had a record, stored-beam current of 258 mA in May, 1988,

and a record quarterly average of 200 mA during Apr-Jun, 1988, about

20% higher than last year's record. Increased current means increased flux. Experiments can be done faster, more sophisticated

measurements can be made, and the quality of the work is higher.

4. There were a number of new users at SURF-II this year, including

industrial users. Some of the new users were from U. California

(Berkeley), U. Nebraska, ARACOR, Lockheed, and KMS Fusion

Corporation. In addition, we are collaborating with United Detector

Corporation and Science Applications Inc to develop new uv and soft

x-ray detectors for radiometric applications, including silicon

photodiodes with enhanced uv response and stability.

5. High Tc superconductors were investigated using x-ray fluorescence

from photon- and electron- irradiated samples as a measure of the

local, partial density of states. There were eight publications on

this project, a collaboration between NIST, U. of Tennessee, U.

Uppsala, and Oak Ridge National Labs.

6. A new "competence" project for "Advanced Studies in Laser Cooling

and Trapping" is being initiated as a collaboration between three

Divisions with expertise in atomic, molecular, and optical physics.

The Radiation Physics Division will develop a vuv laser radiation

source to cool hydrogen atoms to within a few °K.

41
Division 533, Technical Activities (cont'd)

7. Thirty major visiting scientist collaborations were active in FY88

nine in the Far UV Physics Group; seven in the Electron Physics

Group; and fourteen in the Photon Physics Group.

FAR UV PHYSICS GROUP

Far UV Detector Calibrations (L.R. Canfield, N. Swanson, and J. Kerner)

Calibrated transfer standard detectors for the far ultraviolet

continue to be made available to the scientific community and industry,

and recalibrations of detectors already in use are performed as requested. Two facilities with coverages of 5-50 nm and 50-254 nm are

used. A beamline at the SURF-II facility is dedicated to this activity

in the shorter wavelength region. During FY88, 39 calibrations of user

photodiodes were provided, a significant increase over last year's total

of 21.

The NIST far uv detector calibration competence forms the basis for

the radiometric needs of the space research community. In addition,

nearly any measurement activity making use of far ultraviolet photons

e.g. for plasma diagnostics, remote sensing, or irradiation applications,

requires a determination of the magnitude of the flux incident on the

experiment. Such a measure has been provided by NIST transfer standard

photodiodes for almost two decades.

Windowless photoemissive diodes are fabricated within NIST for use

in the region 5-122 nm. Working standards of this type are calibrated by

direct comparison with the photoionization current from a rare gas

ionization "chamber". A special windowless thermopile is used to

transfer these calibrations to the longer wavelengths, where commercially

available MgF2 -windowed photodiodes fabricated to our specifications are used as working standards. Intercomparison calibrations with both types

of these working standards are then used to arrive at calibrations of

detectors to be supplied to outside users.

In a collaboration with industry, the radiometric characteristics of

newly-developed Si photodiodes that may serve as future standards in the

far uv have begun to be studied. Silicon photodiodes are used in

numerous applications to measure visible and infrared radiation and are normally opaque to shorter wavelength radiation. The special silicon

detectors developed in this collaboration were designed to optimize

sensitivity to uv and soft x-ray radiation. Our measurements indicate

that they are the most efficient photodiodes ever measured in this

wavelength region, having an efficiency of about 3000 percent at 10 nm,

about 300 times greater than commonly used photodiodes. These highly

efficient solid state detectors could be used for calibrating radiation

measurement instrumentation, but may also be sensitive enough that they can be used as active elements in remote sensing and other applications.

If tests of stability and homogeneity also give positive results, this

development could lead to a new, high-efficiency radiometric standard

and form the technical basis for a new generation of high-efficiency

array detectors for uv and soft x-ray imaging applications.

42
Division 533, Technical Activities (cont'd)

SURF-II Operation (L. Hughey, A. Hamilton, R. Madden, and W. Wooden)

The performance of SURF-II continues to improve. The average beam

current over the past year is about 170 mA (last year it was 90 mA) , while the average over the last five months is over 200 mA. A new record

beam of 258 mA was recorded during this period. In addition to this, the

beam lifetime has been improved. The half-life of a 200 mA beam is now

about 2 1/2 hours as compared to 1 1/2 hours a year ago for similar

operating conditions. SURF-II has also operated very reliably this year.

Beam was provided to users more than 90% of the scheduled beam time (nine

hours/day; 4 days/week) in FY88.

A number of improvements at SURF have been responsible for the

higher current and longer lifetime. The output of the injector

accelerator (a 10 MeV microtron) was improved by 25-30%, resulting in more electrons injected into the storage ring. Improvements in the

magnetic field gradient profile as a function of electron energy have

resulted in an increase in the ratio of full energy electrons to injected

electrons. Additional increases in the ratio of full energy electrons to

injected electrons are due to the development of automatic systems for

controlling the r.f. power in the storage ring cavity and the vertical

beam expansion (fuzz) as functions of electron energy. These automatic

systems are also responsible for achieving more consistency in full

energy beam current.

Another improvement was: (1) finding one length of r.f.

transmission line, for use during the energy ramp, to promote a resonant

beam oscillation that provides an even greater ratio of full energy to

injection energy electrons; and (2) finding a second transmission line

length, for use at full energy, to promote another stable, selfstimulated beam oscillation that results in a significant beam lifetime

increase

.

SURF-II User Programs (R. Madden)

SURF-II was utilized by a variety of NIST and outside users in FY88

for spectrometer and detector calibrations and for research in surface

science, atomic and molecular physics, and uv and soft x-ray optical

physics. The heaviest use was seen on the Surface Science beamline, BL1, and the Spectrometer Calibration beamline, BL-2, followed closely by

activity on the Angle -Resolved Photoelectron Spectroscopy (ARPES)

beamline, BL-5, and the Detector Calibration beamline, BL-9. The High

Resolution Spectrometer beamline, BL-3, was commissioned. Staff of the

Photon Physics Group and the University of Maryland are now

characterizing the high resolution, 6.65 m spectrometer and initiating an experimental program in atomic and molecular physics.

43
Division 533, Technical Activities (cont'd)

A. Surface Science Beamline, BL-1 (R. Kurtz, T. Madey, and

R. Stockbauer, all from NIST Center for Chemical Physics)

We have supported at SURF- II the establishment by the NIST Surface

Science Division of an experimental capability to study wellcharacterized surfaces. These studies use several SURF-II monochromators

and an ultrahigh vacuum system. Photon stimulated desorption (PSD) of

ions is being studied to understand desorption mechanisms and energetics.

Ion desorption mechanisms for ionically and covalently bonded adsorbates

are investigated. Variable wavelength ultraviolet photoemission

spectroscopy (UPS) is also utilized to study the electronic structure of

metals, oxides, and chemical species adsorbed on these materials.

One of the techniques developed by this group is the measurement of

electron attenuation lengths through molecular films. By measuring the

decrease of a substrate photoemission peak as a molecular film is

condensed and varying the photon energy, the attenuation length can be

measured as a function of electron energy. These are the first

measurements of their kind in the 20-200 eV energy range and are important in modeling the effects of ionizing radiation on materials and

tissue

.

The most exciting work this year was the study of the new, high

temperature superconductors. Using UPS, this group, in collaboration

with a group from the Naval Research Laboratory, investigated the

electronic structure and surface chemistry of high Tc superconductors and

related materials. Using resonant photoemission, they found the

electrons to be highly correlated and almost covalent in nature. The

controversy over the existence of Cu3+ in high Tc compounds was resolved

by studying the Cu resonant satellites. Their behavior is indicative of

Cu2+ rather than Cu3+

. Currently a unique 0 2p satellite observed in

these materials is under investigation.

Chemisorption studies of these materials showed that they react

strongly with H2 0 to form surface hydroxides. This is the first step in

the degradation of these materials when exposed to air. The surfaces

react less strongly with C02 , but the reaction is significant.

Two new areas of research have been initiated by this group, again

in collaboration with the Naval Research Laboratory. The first is a study of the electronic states and surface chemistry of prototype

dispenser cathode materials. In a H2 0 chemisorption study of Ba and BaO on W(110) and W(lll), they observed that a thick layer of hydroxide was

formed, indicating that the H2 0 was able to penetrate the hydroxide layer

and react with the underlying W. The second new area is the study of the

electronic states of metal-on-metal systems, in which controlled amounts

of one metal are deposited onto a single crystal of a different metal.

The resulting electronic energy states are not, as one might presume,

44
Division 533, Technical Activities (cont'd)

simply a superposition of the individual states of the two materials.

Rather, totally new states are observed for thin overlayers. This is an exciting result, suggesting the possibility of tailoring unique

electronic structures for new materials applications.

Work is also continuing on the effects on molecular adsorption of

surface defects in Ti02

. This is an important catalytic material and a model compound for the theory of ion desorption.

A new ellipsoidal mirror analyzer is now ready for installation on

BL-1, the Surface Science beamline. This is a unique instrument, with

only one other operational in the United States. It is capable of

measuring kinetic energy and angular distributions simultaneously. It

will be used for angular resolved photoemission and ion desorption

measurements. A He-cooled sample stage, a side sample preparation

chamber, and a sample transport mechanism are being constructed to

produce single crystal thin films of the high Tc superconductors and of

metal overlayers. The other Surface Science instrumentation has been

moved to BL-8 to continue the electron attenuation length and

photoemission measurements.

B. Radiometric Instrumentation Calibration Beam Line. BL-2 (M. Furst

and R. Graves)

During FY88 there were 7 user groups who used the SURF- II

calibration facility over a period of 39 weeks. Since the photon flux

from the electron storage ring can be calculated from precisely measured

parameters, the synchrotron radiation is used as a radiometric standard

to characterize absolute instrument response over a range of wavelengths

from 4-400 nm. Users were from NASA/Goddard Space Flight Center,

Laboratory for Atmospheric and Space Physics/University of Colorado,

North Carolina State University, Space Sciences Laboratory/U . California

(Berkeley), Naval Research Laboratory, and Space Sciences

Center/University of Southern California. NASA continues to provide

partial support for the facility.

Two of the user groups were new to the facility. The group from

Berkeley made radiometric measurements of components of the EUV Explorer

satellite that will be used for stellar flux measurements. The group

from the University of Southern California measured the efficiency of an

EUV normal incidence spectrometer that will be used to measure the full

solar disk emission spectrum over the range 15-60 nm.

The cryopumps have been upgraded on the large vacuum chamber that is

used to simulate upper atmospheric vacuum conditions. The new pumps

reduce down time for users since they have a larger pumping capacity and

permit a longer time period between regenerations.

45
Division 533, Technical Activities (cont'd)

C. High Resolution Spectrometer Beamline. BL-3 (M. Ginter and D. Ginter,

U. Maryland; and R. Morrison, Talladega College)

The High Resolution Spectrometer Facility installed on BL-3 has been

put through a final set of tests in preparation for its use in two sets

of experiments. The tests indicated that a resolving power of 80,000 is

attainable and absolute absorption measurements with 2% accuracy should

be possible. These characteristics make it one of a few instruments in

the world capable of absolute measurements with such high resolution.

Our first experiments will exploit the very high resolution to

measure the photoabsorption cross-section in the region of the 3s np

window resonances in argon. Although the cross-sections of these

resonances have been measured at lower resolution, our new studies of the

absolute cross-sections at high resolution will enable theorists to

compare their calculations with experiment in a more meaningful way.

The second experiments, which form the main objective of our new

program, will study the Stark effect on the Rydberg levels of parahydrogen. In this work we expect to uncover some of the "quantum chaos"

observed in similar studies with high resolution laser spectroscopy (by

K.H. Welge and others). The experiments will provide the first detailed

look at the photon absorption of highly excited molecular states in an electric field at energies where the transition to chaos is just

occurring. The work is closely correlated with theoretical work in our group that has successfully predicted the onset of chaos in atomic

hydrogen in a magnetic field.

D . Angle-Resolved Photoelectron Spectroscopy Beamline for Molecular and

Chemical Physics. BL-5 (T. Ferrett, J. Hardis , S. Southworth, and A.

Parr, all from Radiometric Physics Division; J. Dehmer, Argonne Nat.

Lab)

Studies were made of resonant photoionization processes in N2 0 and

NO, motivated in both cases by recent developments in theory. The high

resolution capability of the ARPES instrument was used to study

vibrationally-dependent shape resonance effects in N2 0 . Vibrationallydependent effects in the resonant photoionization of polyatomic molecules

are not well understood. New insight into these effects was obtained by

comparison of the ARPES measurements with corresponding fluorescence

measurements and with recent theoretical calculations

.

Our previous ARPES measurements, along with recent theoretical

developments, have led to the prediction of complex resonant states in NO

which arise due to the interaction among several types of resonant

excitations. In addition, the ionization dynamics may be further

complicated by competition with neutral dissociation processes. In order

to characterize these complex resonances, we have made new, more detailed

ARPES measurements on NO

.

46
Division 533, Technical Activities (cont'd)

The ARPES instrument was moved to the Daresbury storage ring during the summer to continue the research program with higher resolution

irradiation capabilities, in collaboration with colleagues at Daresbury.

E. Optical Properties of Materials Beamline. BL-8 (R. Madden; R. Keskikuha, GSFC; D. Husk, U. Virginia)

The 2.2m grazing incidence spectrometer on BL-8 was used with a reflectometer chamber at the exit slit for studies of optical properties

of materials. The characteristics of multilayer reflectors for the 10-20 nm region were studied by R. Keski-Kuha of Goddard Space Flight Center,

and by a group collaboration from the Laboratory for Atmospheric and

Space Physics (U. Colorado) and Lockheed. The beamline was also used by

a U. Virginia group to measure the fluorescent yield of phosphors.

The measurement system was upgraded with a new sample manipulator

and an improved vacuum system. In FY89 we intend to further improve the

existing system and begin planning for a new monochromator and

measurement chamber to support the newly developing vacuum ultraviolet

and soft x-ray multilayer technology.

F. Detector Calibration Beamline. BL-9 (R. Canfield and J. Kerner)

The recently activated SURF-II detector calibration facility

continues to provide calibrations in the 5-50 nm spectral range.

Refinements to the technology have been made as experience has been

developed.

To extend measurements to shorter wavelengths, we are currently

assembling a proportional counter module which will serve as an absolute

standard for detector calibrations into the soft x-ray region (up to 1 keV) . Initially the module will be mounted on BL-9 and be used to

intercompare calibrations made with the standard ionization chamber in

the 200-300 eV range.

The design puts the detector being calibrated behind a thin-windowed

gas flow proportional counter so that both detectors view the same incident beam. Calibrated filters are used to reduce the beam intensity

for the photon counting measurements. The module also features a thin

window isolation from the UHV section of the beamline.

Several research activities have also been carried out with this

facility during FY88.

Photoemission measurements of two classes of high temperature

superconductors have been made, with emphasis on the copper/copper oxide

features found in the 77 eV region. These measurements help in

understanding chemical differences related to processing parameters and

47
Division 533, Technical Activities (cont'd)

to the degree of superconductivity present. The work will continue as new materials and processing techniques become available.

A group of filters used in x-ray laser measurements were characterized in collaboration with personnel from Lawrence Livermore

Labs and AT&T Bell Labs. Calibration of power density in laser research

at Livermore was dependent on these measurements. Also, several special

narrow-band detection devices were characterized in collaboration with

staff from KMS Fusion Inc. These will be used in plasma diagnostics in

the laser fusion program.

A variety of experimental silicon photodiodes were characterized in

collaboration with staff from United Detector Technology Corporation in an attempt to optimize development parameters with a view toward

radiometric applications. The measurements indicate that solid state

photodiodes can be made to be very efficient and relatively stable in the

region 10-200 nm. Further testing will be done to determine their

suitability for radiometric applications.

ELECTRON PHYSICS GROUP

The Electron Physics Group has ongoing research efforts in electron

collision physics including electron-atom collisions, electron-surface

interactions, surface magnetism, electron interaction theory, electron

polarization phenomena, tunneling and scanning electron microscopy, and

electron optics and instrumentation. The wide applicability of electronbased measurement technologies allows us to contribute to the solution of

many diverse scientific and technological problems.

This year saw the expansion of the Electron Physics Group in both

staff and experimental capabilities. Our new scientific staff members

include J. Stroscio (from IBM and previously Cornell), M. Scheinfein (U.

Arizona/Cornell) , R. Cutkosky (NIST/MIT) , R. French (Harry Diamond Labs)

,

and in a shared appointment with the Surface Science Division, M. Stiles

(AT&T Bell Labs/Cornell) . These appointments bring us considerable

additional competence in tunneling and electron microscopy, electronics,

and solid state and surface theory, and we are very pleased that they

joined our Group.

In the past year three major, new experiments were brought into full

operation: the scanning tunneling microscope (STM), the second generation

scanning electron microscope with polarization analysis (SEMPA-II) , and

the spin polarized photoemission facility at Brookhaven (NSLS) . It is

highly unusual for our experimental capabilities to increase so greatly

within a one year period. The expedited completion of some of these

development projects was a direct reflection of the skill and effort of

the new staff members we were able to add to the group last year.

48
Division 533, Technical Activities (cont'd)

We continue our focus on interfacial phenomena with special emphasis

on the use of microscopy to study microstructures, clusters, defects,

growth, and dynamics on the atomic scale. Our SEMPA work involves

studying the effects of size, dimensionality, shape, topography and

epitaxial substrate on magnetic microstructures. The photoemission and

inverse photoemission experiments focus on understanding magnetic

phenomena in novel epitaxial systems through measurements of spin

resolved band structure. Our STM measurements investigate the electronic

structure of atoms, molecules, clusters, and microstructures on

surfaces. The STM allows us to study the growth of microstructures with

atomic resolution. It also permits us to verify, for example, that the

novel epitaxial structures we grow have the physical structure we planned

and that their observed magnetic phenomena results from our tailoring of

the physical structure.

Magnetic Microstructure Research ( J . Unguris, M. Scheinfein, R. Celotta,

D. Pierce, and M. Kelley)

We are investigating sub-micron magnetic structures using Scanning

Electron Microscopy with Polarization Analysis (SEMPA) . The SEMPA

technique was developed at NIST and involves the combination of an ultrahigh vacuum scanning electron microscope (SEM) with detectors that

measure the spin polarization of the secondary electrons. When a magnetic sample is scanned by the SEM, the secondary electrons that are emitted retain the spin orientation that they had in the solid and are therefore directly related to the magnetization in the region probed by

the incident electron beam. The result is an image of the direction and

magnitude of the magnetization vector that is obtained at the same time

as the usual SEM image of surface topography. In practice magnetic

structures can be resolved with a resolution of about 10 nm (0.01

microns) , which is the highest resolution available of any technique for

looking at magnetic structures in reflection. In addition, because the

escape depth of the secondaries is approximately 2 nm, SEMPA is an ideal

probe of surface and thin film magnetism.

We have recently completed construction of a new SEMPA facility

centered about a new SEM that is more reliable than the old one and is

also a scanning Auger microprobe. The Auger microprobe provides us with

a map of the chemical composition with about the same resolution and from

the same area as the magnetic and topographic images. This provides us with a unique tool to study the relationships between magnetic

microstructure and surface chemistry.

Current work at the new facility involves studying the structure of

domain walls at the surface of iron crystals. We have found that the

domain walls have a different width and rotational sense at the surface

than in the bulk. We have observed these walls for surfaces prepared in

different ways and at temperatures up to the Curie temperature (750 C)

.

49
Division 533, Technical Activities (cont'd)

In addition to basic research, we also have been collaborating with

private industry by using SEMPA to help solve applied magnetics problems.

An example of this is our current work with Honeywell on a new type of

memory chip based upon magnetic bits with micron dimensions. We were able

to image the magnetization inside of these bits with a spatial resolution

previously unavailable to Honeywell and thus provide them with

information useful in extending the performance of this device.

We have established joint research efforts with industry, other

government laboratories, and universities. We have received a multitude

of samples from major corporations interested in exploring the

applicability of this technique to outstanding scientific and

technological problems of concern. We expect these collaborative efforts

to be scientifically fruitful, intellectually stimulating, and mutually

beneficial during the next year.

Scanning Tunneling Microscopy ( J . Stroscio, R. Dragoset, P. First,

D. Pierce, and R. Celotta)

The scanning tunneling microscopy (STM) program in the Electron

Physics Group is aimed toward understanding the physics of low

dimensional structures. This focus contributes toward the microstructure

emphasis in the Electron Physics Group by extending our capabilities to

examine and study structures with atomic resolution. The STM operates by

the principle of quantum tunneling of electrons from a sharp probe to the

examined specimen, which is held within atomic distances of the probe.

Our STM has recently been fine tuned and is currently operating with 3 A

lateral resolution and an extremely high perpendicular sensitivity of

0.01 A (1 pm). The STM is operating in an ultrahigh vacuum system with

thin film growth and characterization facilities.

We have begun investigating metal structures grown on GaAs

substrates by molecular beam epitaxy (MBE) techniques. GaAs is thought

to be the semiconductor of the future because of its very high electron

mobility which is useful in ultra-high- speed semiconductor applications.

Using the STM, we have discovered an extremely novel system of one- dimensional atomic structures that form with Cs atoms on GaAs(llO)

surfaces. This is the first observation of such structures being formed

with this system.

In the STM images the Cs atoms are individually observed to line up

(atom by atom) in single atomic chains along the high symmetry direction

of the GaAs (110) substrate. The Cs chains are observed to be > 50 A

apart, thereby representing a truly one -dimensional system of metal

atoms. Interesting scientific questions concerning the physics of such

one -dimensional structures, such as are these atomic metal "wires" really

metallic (as defined by a partially filled electron band) , are being

pursued with the STM. By exploiting the dependence of the quantum

50
Division 533, Technical Activities (cont'd)

tunneling on voltage difference between the probe and sample, we are able

to investigate the electronic properties of these structures, such as the

development of the electronic band structure and nature of the metalsemiconductor bonding. Although these atomic "wires" are formed

naturally, they demonstrate the ultimate limit of structures that may be

fabricated with semiconductor technology.

A second area of investigation with the STM is concerned with the

study of ultra- thin magnetic films on surfaces. This work is synergistic

with our studies of magnetic microstructures using the SEMPA technology.

We are presently studying epitaxially grown bcc Fe films on GaAs(llO)

substrates. Fe is one of the few materials which grows epitaxially on

GaAs . Previous studies by NRL researchers have shown anomalous magnetic

behavior in ultra- thin films. The origin of this behavior has been

attributed to defects or strain in the Fe films.

Our initial measurements show that Fe does not grow in a layer by

layer mode on GaAs but forms 3-dimensional clusters during an initial

growth phase at 25 C. These clusters are observed to be about 50 A in

diameter. The morphology of these clusters show a preferential growth

direction with grain boundaries that might explain some of the anomalous

behavior in the magnetic properties. Further studies on the temperature

dependence of the growth process is being investigated.

Although the physical microstructure of the magnetic thin films can

be obtained with the STM on an atomic scale, the magnetic properties

cannot. With the objective of probing magnetism on the atomic scale, we have been developing an STM type of system to be sensitive to surface

magnetism. The experiment is a hybrid of technology developed in the

Electron Physics Group, consisting of a scanning tunneling microscope

with electron spin detection of electrons emitted from the tunnel

junction. Earlier research by Russell Young at NIST showed the

feasibility of secondary electron detection with the STM, and researchers

at IBM Zurich have recently confirmed these experiments.

The "magnetic" STM and associated components are currently being

fabricated and will be assembled in early FY89. The successful completion

of a magnetic microscope with atomic resolution would open up a new

frontier in micromagnetism.

Electron - Atom Collisions Studies (M. Kelley, J. McClelland, and D. Oza)

Our purpose is to study, in as complete a manner as possible, the

interactions important in low energy collisions between electrons and

atoms. We employ optical state preparation techniques to prepare beams

of electrons and atoms in well defined quantum states and perform

scattering measurements to determine the dependence of various collision

cross sections on the initial state of the incident electrons and atoms.

51
Division 533, Technical Activities (cont'd)

Such state-selected experiments provide substantially more information

about the collision than is available from conventional measurements of

differential scattering cross sections. We are particularly interested

in the influence on the collision of the spin state of the incident

electrons and atoms. Determination of this spin dependence provides very

direct information about both exchange and the spin-orbit interaction,

and provides a very stringent reliability test for current theoretical

scattering calculations.

We have made spin dependent measurements for both elastic and

inelastic scattering. Elastic scattering measurements were performed at an incident electron energy of 54.4 eV and at scattering angles in the

range from 20° to 135° The most surprising result was that, even for

sodium, a relatively light target, the spin-orbit interaction plays a significant role in the scattering. The effect on the scattering cross section is comparable in magnitude to that due to exchange. Current

state-of-the-art theoretical calculations do not accurately reproduce our measurements, indicating that further theoretical work is necessary.

We have also studied inelastic scattering by way of superelastic

scattering from the first excited state. Spin-polarized and oriented

sodium atoms are prepared in the excited 3P state by optical pumping with

circularly polarized light. By detecting only electrons that have deexcited these atoms and gained the 2.1 eV excitation energy of the atoms,

we are able to study the 3S - 3P transition with very great detail. Our

measurements span the energy range from 2.0 eV to 52.3 eV and the angular

range from 10° to 130°. We find that spin plays a very important role at

energies up to 20 eV. At the higher energies, around 50 eV, we are no longer able to see any spin dependence.

We are also attempting to provide the theoretical data for

comparison with our experiments. Extensive ab initio scattering

calculations are being made. These calculations include the four lowest

lying atomic levels exactly and use an optical potential to account for

the higher levels and the continuum. When complete, these calculations

should provide the best theoretical estimates to date for the spin

dependencies observed in our measurements.

Our current efforts are directed at extending the energy range in

which these measurements are possible. Specifically, we wish to perform

elastic scattering measurements at energies below the ionization

threshold of 5.1 eV. Theoretical calculations should be quite good at

the lower energies, and we wish to provide both elastic and

inelastic data for comparison with theory over the range of energies

where current calculations have the most difficulty, from somewhat below

to several times the ionization threshold.

52
Division 533, Technical Activities (cont'd)

Inverse Photoemission Spectroscopy (M. Hart, D. Pierce, and R. Celotta)

In recent years we have applied the spin polarized electron source developed in this group to the study of ferromagnetic metal surfaces. By

coupling this low energy spin polarized source with a UHV chamber

equipped with a sample manipulator, an Auger spectrometer, and a LEED

system a variety of unique experimental techniques have been employed to

investigate the magnetic, chemical, and electronic properties of metal

surfaces. Currently, we are focusing on a spin polarized inverse

photoemission (SPIPES) technique to study transition metal surfaces.

Inverse photoemission complements photoemission studies by yielding

energy and momentum resolved information about the unoccupied band

structure at the surface. An electron incident upon the sample can undergo a radiative transition and become bound in a vacant orbital of

the solid. The flux of 9.7 eV photons emitted from the sample is

measured as a function of the energy, angle of incidence, and spin of the

electrons. Since the energy, momentum, and spin are conserved, the final

state is well defined. Because of its spin selectivity, SPIPES is

applicable to a large number of areas of current interest in

ferromagnetic materials.

We have recently completed a SPIPES investigation of the clean

Ni(001) surface and the c(2x2) absorption systems 0/Ni(001) and

S/Ni(001). For clean Ni(001), we found a minority- spin character for the

unoccupied 3d band, but an essentially non-magnetic character for the Ni

4sp band. These spin-dependent results confirm previous spectral

assignments made for Ni(001). No spin dependence of the Ni(001) image

potential surface state was found.

We are now investigating the electronic and magnetic properties of

ultra- thin, epitaxial, metallic films deposited on metallic substrates

with SPIPES. The first thin film system under study, cobalt overlayers

evaporated in situ on Ci(lll), has yielded interesting preliminary

results. Changes in both the energy and spin character of the unoccupied

minority and majority spin cobalt d bands have been observed with varying

film thickness. These observations may lead to significant conclusions

about the nature of ferromagnetic systems with reduced dimensionality.

Spin Polarized Photoemission at NSLS (D. Pierce and R. Celotta)

We have been participating in an effort at the National Synchrotron

Light Source (NSLS) to study novel magnetic systems created in situ by

molecular beam epitaxy (MBE) . To date, the work has concentrated on the

establishment of a spin-polarized, angle and energy resolved

photoemission apparatus on the U-5 beamline of the UV storage ring.

53
Division 533, Technical Activities (cont'd)

This project is unique in a number of ways. First, the research

team consists of 11 principle investigators from 9 institutions

nationwide. These are national labs (NIST, Argonne , NRL, and NSLS)

,

universities (Rice, Texas at Austin, Northwestern, and U. California at

Irvine) and an industrial lab (AT&T Bell) . This group functions both as an NSF Materials Research Group as well as an NSLS Participating Research

Team. Second, the beamline is the only spin polarized facility in the

United States and the only one in the world with a movable spin analyzer

to permit angular studies. Third, it is one of very few beamlines in

the U.S. to have an MBE capability. Finally, because of the demanding

nature of the experiment, we are fortunate to have the highest flux UV

beamline at NSLS. It is based on an undulator currently installed in a straight section of the ring. During the next two years this same group,

acting as an Insertion Device Team, will install a new state-of-the-art

undulator now under construction.

The beamline has recently been used to take spin polarized

photoemission data. In the first experiment, our colleagues at NSLS

have examined the angle resolved spectra of Fe(110) both in a clean state

and with adsorbed sulfur. The ability to make both angle and spin

resolved photoemission measurements extends greatly previous work and,

even in the first experiments, calls into question previous

interpretations made in the absence of spin resolved data.

We have begun measurements on the Fe on Cu(100) system. The first

few layers are thought to grow epitaxially as fee Fe, as opposed to the

normal bcc form. The object of the experiment will be to observe the

magnetic properties, e.g. anisotropy, Curie temperature, remanence

,

magnetization, etc., as a function of layer thickness and growth

methodology, and to correlate them with the spin dependent electronic

structure we measure. We expect this facility to greatly extend our ability to study new and interesting magnetic systems.

Electron Optics (M. Kelley and M. Scheinfein)

We have added substantially to our capabilities for the design and

characterization of new electron-optical instruments. These new

capabilities include sophisticated numerical algorithms used to compute

electrostatic and magnetic lens fields, and improved methods of

determining the optical properties of these fields. Paraxial and

aberration properties can be accurately determined for electrostatic or magnetic lenses. Non-paraxial , all-order, electrostatic ray- tracing is

also used for more accurate modelling of novel designs. Furthermore, a third order matrix method has been developed for use in the design and

characterization of our electron optical systems.

54
Division 533, Technical Activities (cont'd)

The second generation electron spin polarimeter (SEMPA detector) and

transport optics were designed, built, and interfaced to the JEOL JAMP 30

Scanning Auger Microprobe. The system, complete with scan compensation,

has been fully characterized and determined to function as originally

designed.

A third generation SEMPA detector and transport optics were designed

to further improve the performance of the system. The technology for

this new detector, which has been built and tested at NIST, has been

transferred to Physical Electronics, Inc (PHI), who will develop a commercial instrument based on this design. In addition, a novel optical

system for secondary electron extraction has been designed and

implemented for the PHI system. This novel system is currently being

applied in the PHI laboratory for their own scanning ion microscopes.

The third generation SEMPA detector has also been interfaced to a standard 180° hemispherical analyzer with input and output optics. This

instrument is used to study spin-polarized photoelectron spectroscopy in

a project cooperatively pursued with researchers at Brookhaven National

Labs. The new optical system will eliminate spurious polarization

asymmetries induced by instabilities in the positioning of the beam in

the Brookhaven storage ring.

Electron Theory (D. Penn)

Our purpose is to study various aspects of electron-electron

interactions in solids with application to high Tc superconductivity and

surface magnetism.

We have examined the significance of satellites at binding energies

of about 12 eV that are observed in photoemission experiments in the high

Tc superconductors La-Sr-Cu-0 and Y-Ba-Cu-0. The satellites are assumed

to be caused by intra d-shell shake-up processes with a Cu 3d8 final

state. Using the t matrix approach, we studied the effect of the

electronic correlations on the one electron band structure. We found

that it takes a large Coulomb interaction energy of 5 eV at the Cu site

to account for the position of the satellite. This shows that the 3d8

, two hole, bound state is a high energy excitation comparable to the 3d

band width, and that electron correlations are important in the high Tc materials

.

We have also studied the interaction between two test changes in a solid which can be described in terms of a total dielectric function, e, that includes electronic and lattice polarization. We have shown that

the eigenvalues of e -1 are < 1 for crystal stability. We have

constructed such a dielectric function in the mean field approximation

55
Division 533, Technical Activities (cont'd)

and shown that the correct phonon modes are determined by the low energy

poles of e” 1

. Such an approach may be useful in the study of

superconductivity

.

We are continuing to study the process of Auger decay in the

interaction of metastable helium with metal surfaces. When metastable

helium atoms approach the surface of a metal, an Auger decay can take

place in which a metal electron falls into an empty Is state of helium

and a second electron (the Auger electron) is ejected. Measurements of

the total number of Auger electrons ejected from nickel for opposite

spin-polarizations of metastable helium show a difference (normalized)

that increases from 0 to 10% as the kinetic energy increases. We are formulating a theory for this asymmetry. In contrast to the standard

interpretation, we expect the sp-electrons to be of crucial importance.

Whereas the d-electrons carry the main moment, the sp-electrons have the

largest overlap with the helium.

PHOTON PHYSICS GROUP

The Photon Physics Group investigates the interaction of

electromagnetic fields on atoms and molecules in various environments in

support of radiation measurements and standards programs important to

NIST and the outside technical community. This work includes

theoretical and experimental studies on the electronic structure of

atomic and molecular systems in field free environments and in strong

external fields. The Group has specialized in ionization phenomena and

in nonlinear or multiphoton laser-atom interactions.

Studies are currently focused on molecular excitation dynamics,

shell contraction in atoms, multiphoton transitions, atoms in high

electric and magnetic fields, and the structure of highly excited atoms.

Collaborative work is directed toward ultrasensitive analysis through

resonant multiphoton ionization, the measurement of picosecond vuv pulses

by nonlinear cross correlation techniques, and the identification of

highly excited atomic states suitable for soft x-ray laser. For many of

the activities, synchrotron radiation from NIST-SURF-II or BrookhavenNSLS is used as a source of tunable vacuum ultraviolet and soft x-ray

radiation

.

Multiphoton Ionization Applied to Ultrasensitive Trace Analysis

(T. Lucatorto and C. Clark)

This is a collaborative effort with the Mass Spectrometry Group in

the NIST Center for Analytical Chemistry having the goal of developing a resonance ionization mass spectrometric (RIMS) capability with sub partper-billion isotopic abundance sensitivity. Present thermal ionization

mass spectrometers have an ultimate isotopic abundance sensitivity of

56
Division 533, Technical Activities (cont'd)

about one part in 10 7

. By putting isotopic selectivity into the

resonance ionization step, we hope to improve the overall sensitivity by

three to five orders of magnitude.

Our RIMS studies have used special narrow bandwidth pulsed lasers to

perform isotopically selective ionization. Results with the isotope pair

10 Be: 9 Be show laser selectivities in excess of 3000:1, which would, in

principle, increase the overall isotopic abundance sensitivity from 1 : 1

0

7 to 3xl0 10

. However, due to the poor duty factor of the pulsed laser

(roughly 1:10 5 ), the sample utilization efficiency is very low, with the

result that sensitivities of only 1 : 107 are attainable with practical

samples

.

The problem of poor sample utilization efficiency is perhaps the

single most troublesome limitation for RIMS. To attack this problem, we have begun studies on pulsed laser ablation as a method of atomization

that is matched to the duty cycle of the ionization laser. Preliminary

studies indicate that there are three mechanisms that limit the

effectiveness of the laser pulsed ablation technique: laser plasma

formation, thermal stress induced exfoliation, and molecular compound

formation (e.g. oxides). In an attempt to reduce the adverse effects of

these mechanisms, we have begun experiments on thin films of relatively

volatile metals. Films of Zn produced by sputtering have been ablated

and show advantageously low plasma formation. Present efforts are directed towards developing a suitable technique to co- sputter Zn and the

analyte so that the Zn serves as a non- interfering matrix in the

compositional analysis of the analyte.

Resonance Ionization Mass Spectrometry Data Service (E. Saloman)

The techniques of Resonance Ionization Spectroscopy (RIS) and

Resonance Ionization Mass Spectroscopy (RIMS) have demonstrated high

elemental sensitivity and the potential for almost 100% efficiency. They

should become most valuable tools for analytical chemistry. For these

techniques to meet their potential, they must be made available to

practicing analytical chemists. Presently, much of the information

needed to apply RIS and RIMS is scattered in several atomic data bases,

which generally contain much more information than the chemists would

need. It is the objective of this project to organize the available data

and supplement it with calculations where gaps exist to provide the

needed information to permit the application of RIS and RIMS to routine

use in analytical chemistry.

Preliminary data sheets have been completed for ten elements this

past year. Included are calculations of previously unmeasured excited

state photoionization cross sections, transition rates, and

autoionization rates. In the next year more data sheets will be

57
Division 533, Technical Activities (cont'd)

completed. In addition the format of the data sheets will be further

refined, in collaboration with the RIS-RIMS community, including the

Institute for Resonance Ionization Spectroscopy at the U. Tennessee.

Soft X-Ray Emission Studies of Advanced Materials (D. Ederer)

Soft x-ray fluorescence can provide important information about the

electronic states of solid state materials. Fluorescence measurements

can be used to study the properties of alloys, impurities, clusters,

surface layers, organics, and other fragile compounds. A novel, high

sensitivity soft x-ray spectrometer especially designed for fluorescence

measurements has been in operation at the NSLS for almost two years now

and is the proud accomplishment of a joint NIST-U. Tennessee-Oak Ridge

National Laboratory collaboration. Recent experiments have proven it to

be one of the best instruments in the world for soft x-ray fluorescence

measurements

.

The unique capabilities of the instrument has attracted a number of

collaborators including scientists at the University of Hawaii, the

University of Connecticut, the University of Uppsala, AT&T Bell

Laboratories, and NIST colleagues from the Institute of Materials Science

and Engineering and the Institute for Computer Science and Technology.

Through collaboration with our IMSE colleagues, we have studied the

electronic structure of the icosahedral phase of an aluminum manganese

alloy, as well as the electronic structure of the YBa2 Cu3 07 _ e and Bi-SrCa-Cu-0 superconducting ceramics. This last area of research has been

funded as part of a DoC initiative on high temperature superconductors.

With additional resources from this initiative, we have added a solidstate physicist (D. Mueller/Cornell) and a visiting scientist to the high

Tc superconductivity project.

A few of the highlights of this program are:

a) High Tc Superconductors:

The oxygen K, soft x-ray emission spectra for the YBa2 Cu3 Ox compounds with x=6 , 6.5, and 7 was obtained and compared with

x-ray emission spectra determined from recent band structure

calculations. The K emission spectrum of 0 provides a measure

of the p-type local partial density of states (p-LPDOS) at the

oxygen sites. Good agreement is found with the calculated

spectrum for x=7 . As x decreases from 7 to 6.5, a chemical

shift of the entire spectrum to lower energy indicates that

screening is modified for all oxygen sites. The integrated

intensity of the spectra is nearly unchanged by oxygen removal,

indicating an increase in p-PDOS per oxygen site. These

58
Division 533, Teahnical Activities (cont'd)

results and changes in the spectral shape suggest that

itinerant electron density near the 0 atoms is reduced and

bound electron density is increased as oxygen is removed.

We have also measured the soft x-ray K emission spectrum from

oxygen in the Bi-Sr-Ca-Cu-0 superconductor and found it

identical with the 0 K emission from the 123 superconductor.

The 0 K and the Bi valence-N6 7 emission were in good agreement

with spectra modeled after calculations based on linearized

augmented plane wave method and local density band structure

calculations

.

b) Electronic Structure of Buried Interfaces

As semiconductor devices become smaller and smaller, and as it

has become possible to synthesize new materials based on thin

layered structures, the measurement of interface properties

within a bulk has become extremely important to industry. This

is because it is often the microstructural properties of the

interface that control the behavior of the material. Interface

measurements are very challenging since most diagnostic methods

generate responses from the surface of the material and the

bulk of the medium that completely overwhelm the response of

the interface.

It is difficult to study the electronic structure of the

interface between different materials basically because the

interface is buried under a layer of material. Surface

sensitive probes like photoelectron spectroscopy cannot be

effective. X-ray fluorescence spectroscopy, although not

surface sensitive, is not normally efficient enough. However,

this drawback was overcome in the present experiments by making

a multilayer structure consisting of 50 layers of carbon films

interdigitated with silicon films. In one group of samples the

thickness of the silicon film was varied from 0.3 run to 3.0 nm,

with carbon film thickness fixed at 3.0 nm. In another group

of samples the silicon film thickness was fixed and the

thickness of the carbon was varied. By this sample preparation

technique, it was possible to enhance the signal- to-noise ratio

by a factor of 50 over a single C-Si interface.

The fluorescence was excited by near threshold soft x-rays

from the National Synchrotron Light Source at Brookhaven

National Laboratory and detected by an ultrahigh sensitivity

spectrometer. The interface signal was clearly distinguishable

59
Division 533, Technical Activities (cont'd)

from the signal generated in the bulk. The silicon L2 3 emission band from the interface resembled that of SiC and the

silicon emission from the bulk resembled that of amorphous

silicon.

This is a cooperative program with Lawrence Berkeley

Laboratories and the University of Wisconsin.

c) Electronic Structure of Semiconductor Materials

In collaboration with AT&T Bell Labs, we studied the local

valence band density of states in A^Ga^^s. This material

has important applications in the semiconductor industry

because it has a higher conductivity and smaller, variable

(with x) band gap relative to silicon.

The soft x-ray fluorescence from the valence band to the 2p

aluminum core holes probes the local band structure with mostly

s like symmetry. One observes a shift of several tenths of an

eV in the energy position of the partial density of states

localized at the aluminum site relative to the gallium in the

crystal lattice. This is a new insight into semiconductor

alloys that has not been incorporated into the theoretical

description of these systems. Information like this has not

been obtained before because techniques like photoelectron

spectroscopy are not atom-specific, but rather provide a measure of the total valence band density of states integrated

over all the atomic sites.

We plan to study other materials, like InP, with our Bell Labs

collaborators. Also of interest are the properties of

multilayer materials made with alternating Alx Ga 1

_ x As and GaAs

thin films to form superlattices.

d) Radiation damage in insulators

In a collaboration with the University of Hawaii, we studied

electron induced radiation damage for two silicon compounds,

Beryl (Be-Al-Si-O) and SiO. The Beryl radiation damage

suggests a localized damage about the silicon, whereas the Al

and Be retain their oxide- like structures. Silicon is reduced

as a result of electron bombardment to a mixture of amorphous

and crystalline Si. The radiation damage in SiO is similar to

that of Beryl in that a mixture of amorphous and crystalline Si

is observed. The study of radiation damage in these compounds

is important because of their use as window materials in uv

lasers

.

60
Division 533, Technical Activities (cont'd)

During the next year we will be continuing our studies of the high

Tc superconductors and commence studies on implanted species of

importance to the semiconductor industry. A new monochromator has been

added to the instrumentation to allow for narrow band irradiation.

Ionization Dynamics of Fundamental Atomic Systems (D. Ederer; D. Caldwell

and J. Jimeniz-Mier , U. Central Florida)

A series of studies done in collaboration with the University of

Central Florida has been carried out at SURF using the polarization of

the synchrotron radiation beam as a probe of molecular and atomic

photoionization dynamics. In helium we made the first measurements of

the angular distribution of the 304 A radiation following

photoionization. The distribution reflects the alignment of the ion with

the electron in a 2p orbital. The alignment is related to the ratio of

the photoionization cross section to final continuum states of d symmetry

to the total cross section for ionization and excitation of the electron

to a 2p orbital. The measurements were in good agreement with close

coupling calculations and complemented other experiments that measure the

correlation among the electrons in this fundamental two electron system.

The results were published in Phys . Rev. Letters.

This year measurements are being made in the energy range of a twoelectron excitation resonance to determine how the correlation

introduced by an additional excitation channel affects the alignment of

the ion. These measurements will be completed in FY88.

Atomic Structure of Laser-Excited Atoms (T. Lucatorto and C. Clark).

Our group has a unique capability to measure the vuv photoabsorption

(between 8 nm and 65 nm) of laser -excited and laser- ionized atoms. The

IR-100 award-winning instrumentation includes a state-of-the-art, vuv

spectrometer with a 1024 channel photoelectric detector, a 20 ns pulsed

vuv source, several pulsed tunable dye lasers, and a high temperature (up

to 2500° C) heat-pipe oven.

Photoabsorption studies of laser-excited and laser- ionized atoms

have uncovered the dramatic effects of relatively small changes in

electron screening on orbital collapse. Presently we are focusing

attention on the 3p-photoabsorption spectra of the transition metals (Sc,

Ti, V, Cr, Mn, Fe, ). These spectra are all characterized by a single giant 3p -» 3d resonance structure in the 50 eV energy range. Cr,

however, is an exception because it has an additional, we 11 -developed

Rydberg structure lying above the giant resonance. Up to now the unique

status of Cr was thought due to its being the only member with an unpaired 4s-electron in the ground state (3p6 3d5 4s 7 S). Our recent

high resolution measurements of the isoelectronic Mn+ spectrum, which

61
Division 533, Technical Activities (cont'd)

showed no we 11 -developed Rydberg structure, show this not to be true

however. The definitive Mn+ spectrum obtained is stimulating a parallel

theoretical effort to explain the exceptional behavior of Cr.

This work is a collaboration with the Atomic and Plasma Radiation

Division, the University of Hamburg, and the National Institute of Higher

Education (NIHE) , Dublin.

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

Electron Beam at SURF (D. Ederer)

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

utilize both lasers and synchrotron radiation. Synchrotron radiation is a source of pulsed VUV radiation that can be used to produce excitation

leading to chemical reactions. By probing a sample of excited molecules

undergoing a reaction with a laser locked to the storage ring radio

frequency, we may obtain detailed information on the dynamics of the

chemical reaction. The mode locked Nd:YAG laser with the doubler and Qswitch has arrived and we plan to install it on the SURF Storage Ring.

The work will be advanced by the arrival of a guest scientist, who will

work full time on this program during FY89.

Our long-term collaboration to study laser-prepared states with the

Universite de Paris -Sud in Orsay, France, is winding down. A review of

photoionization from excited states, co-authored by D. Ederer and F. Wuilleumier, has been published early in 1988 as a book chapter in

Advances in Atomic and Molecular Physics entitled "Photoionization and

Collisional Ionization of Laser Excited Atoms Using Synchrotron

Radiation.

X-Ray Attenuation Cross Sections (E. Saloman)

A comparison has been carried out, in both tabular and graphical

form, over the energy range 0.1-100 keV between our data base of

experimental attenuation coefficients (total absorption cross sections)

and cross sections obtained using two widely used sets of absorption

cross section values: the semi-empirical set of recommended values

produced by Henke et al . , and a theoretical set of recommended values

calculated by Scofield (and extended at our request down to 0.1 keV) . We

also evaluated whether Scofield's calculation should be subject to a renormalization from a Hartree-Slater to a Hartree-Fock atomic model and

determined that the experimental data tends to argue against such

renormalization.

A compilation of experimental and theoretical x-ray attenuation

coefficients for this energy range (as well as a bibliography of the NIST

data base), prepared in collaboration with J.H. Scofield of Lawrence

Livermore National Laboratory, was published this year.

62
Division 533, Technical Activities (cont'd)

This work is a collaboration with the Ionizing Radiation Division.

Atomic Properties and Data (E. Saloman)

Relativistic multi-configuration Dirac-Fock methods have been

applied to the calculation of atomic and ionic energies and transition

probabilities. An initial study has been completed. It is an investigation of the energies and oscillator strengths in the ground

state configuration of the sulfur isoelectronic sequence. Results have

been obtained for all transitions within this configuration for the 77

ions from sulfur to uranium. They demonstrate striking effects in the fvalues corresponding to atomic numbers where different configurations

become important. A report on these effects was published in Physical

Review A. The detailed data will be published in Atomic Data and Nuclear

Data Tables.

Next year calculations will be made to determine certain transition

probabilities which are very sensitive to the method used to calculate

them. The significance of the change in the wave functions of "spectator

electrons" between initial and final states will be explored.

This work is a collaboration with the Atomic and Plasma Radiation

Division.

Theoretical Atomic. Molecular, and Optical Physics (C. Clark and L. Pan)

Theoretical AMO physics in the Photon Physics Group was focused on

two main areas: core- and multiply-excited states of atoms in gas and

condensed phases, and high-order multiphoton processes.

Our atomic structure work has been carried out in support of

experimental efforts in our Division, in the Atomic and Plasma Radiation

Division, and in other institutions; and with other theorists in the

Surface Science Division and elsewhere. The principal achievements of

this work have been:

1) Identification and classification of 3p -* 5s photoabsorption

features in atomic Mn, and preliminary interpretation of the 3p -*• 3d

"giant resonance" features in Mn, Mn+

, and Cr;

2) Analysis of 4d9 4f fine structure seen in electron energy loss

spectroscopy of Ba in the YBa2 Cu3 07

_ x high-Tc superconductor;

determination of the valency of Ba in this compound from comparative

analysis of photoabsorption data; and identification of 4d10 5p 6 -» 4d9 5p 5 5d2 double excitation in Ba photoabsorption;

63
Division 533, Technical Activities (cont'd)

3) Interpretation of x dependence of oxygen K emission peaks in

YBa2 Cu3 07

_ x compounds in terms of fractional valence of oxygen, based on Hartree-Fock atomic structure calculations; and investigation of role of

0' and 0

2 " resonances in electron-stimulated desorption of oxygen from

surfaces

;

4) Identification of term dependence in the 4d9 nf series of I VIII and

Xe IX;

5) Computation of multichannel quantum defect (MQDT) parameters of the

2p

5

ns and 2p 5 nd channels of Ne in good agreement with experimental

determinations; and critical evaluation of effects of core polarization

and the relationship of MQDT and Slater-Condon descriptions.

Work on high-order multiphoton processes has centered around the

development of a general computer code for evaluating perturbation theory

of atomic hydrogen in a radiation field to arbitrarily high order. This

code has begun to produce results on level shifts and nonlinear

susceptibilities up to 90th order, an order of magnitude higher than any

previous calculations. The principal qualitative results obtained thus

far are:

1) Development of a parameterization technique that separately treats

background and resonant contributions, so that the behavior of level

shifts and nonlinear susceptibilities can be described by a few

parameters even in a spectral region containing infinitely many

resonances

;

2) The determination of a "critical intensity" at which the

contributions from higher orders of perturbation theory exceed those of

lower order. These intensities are comparable to those at which

saturation of multiphoton ionization is observed in experiments;

3) Computation of cross-sections for generation of high harmonic

radiation, and the evaluation of critical intensities that are in good

correspondence with those inferred from the "plateau" behavior of recent

experiments

.

64
SPONSORED WORKSHOPS, CONFERENCES, AND SYMPOSIA

Division 533, Radiation Physics

R.J. Celotta organized and chaired the Research Advisory Committee

Symposium on NBS Activities in Scanning Tunneling Microscopy, NBS

,

Gaithersburg, MD, May 20, 1988.

M.H. Kelley organized the Atomic Physics Program Contractor's Workshop

with U.S. Department of Energy, Office of Basic Energy Sciences, Division

of Chemical Sciences, Hyatt-Regency Hotel, Bethesda, MD August 31 - September 1, 1988.

T.B. Lucatorto organized, jointly with University of Tennessee, the 4th

International Conference on Resonance Ionization Ionization Spectroscopy

and Its Applications, NBS, April 11-15, 1988.

R.P. Madden organized a symposium on Major VUV Radiometric Facilities for

the SPIE meeting on X-Ray Instruments, Multilayers and Sources, San

Diego, CA, August 14, 1988.

D.T. Pierce organized and chaired the Gordon Research Conference on Electron Spectroscopy, Wolfboro, NH, July 18-22, 1988.

65
INVITED TALKS

Division 533, Radiation Physics

Celotta, R.J., "Scanning Electron Microscopy with Polarization Analysis:

Studies of Magnetic Microstructure," Am. Vac. Society, Annual Meeting,

Anaheim, CA, Nov. 2, 1987.

Celotta, R.J., "Polarized Electron Probes in Atomic and Surface Physics,'

Australian Bicentenary Congress, Sydney, Australia, January 26, 1988.

Celotta, R.J., "An Introduction to Scanning Tunneling Microscopy," STM

Symposium, National Bureau of Standards, Gaithersburg, MD, May 20, 1988.

Celotta, R.J., "Improved Low-Energy Diffuse Scattering Electron-Spin

Polarized Analyzer," Gordon Conference on Electron Spectroscopy,

Wolfeboro, NH, July 20, 1988.

Dragoset, R.A.

,

"Scanning Tunneling Microscopy," Physics Seminar,

University of Maryland Baltimore County - Physics Department,

Catonsville, MD, Feb. 10, 1988.

Furst, M.L., "SURF-II Radiometric Instrumentation Calibration Facility,"

SPIE Conference on X-ray Instrumentation in Astronomy, San Diego, CA,

August 17, 1988.

Kelley, M.H., "Spin Dependence in Electron Atom Scattering," IXth Atomic

Physics Workshop, U.S. Dept, of Energy, Office of Basic Energy Sciences,

Division of Chemical Sciences, Bethesda, MD, August 31, 1988.

Lucatorto, T.B., "Enhanced Isotope Abundance Sensitivity and Sample

Utilization Efficiency in Pulsed RIMS," Workshop on Advanced Laser

Techniques in Chemical Analysis, NIST, November 4, 1988.

McClelland, J.J., "Scattering of Spin-polarized Electrons from Optically

Pumped Sodium," Physics Colloquium at Wesleyan University, Middletown,

CT, October 1, 1987.

McClelland, J.J., "Scattering of Spin-polarized Electrons from Optically

Pumped Sodium," Physics Colloqium at University of Kentucky, Lexington,

KY, October 21, 1987.

McClelland, J.J., "Improved Low-Energy Diffuse Scattering Electron- Spin

Polarized Analyzer," Gordon Conference on Electron Spectroscopy,

Wolfeboro, NH, July 20, 1988.

Ott, W.R.

,

"Far-Ultraviolet Detectors, Spectrometers, and Optics,"

Council for Optical Radiation Measurements Annual Meeting, National

Bureau of Standards, Gaithersburg, MD, May 18, 1988.

66
Division 533, Invilied Talks (cont'd)

Penn, D.R., "Analysis of Spin Polarized Inelastic Electron Scattering,"

Workshop on Magnetism of Surfaces, Laguna Beach, CA, October 30, 1987.

Penn, D.R., "Spin Polarization of Secondary Electrons in Metals," Rice

University, Houston, TX, January 26, 1988.

Penn, D.R.

,

"Total Dielectric Function, Algebraic Sign, Electron-Lattice

Response, and Superconductivity," Chalmers University, Chalmers, Sweden,

April 15, 1988.

Penn, D.R.

,

"The Role of Inelastic Exchange Scattering in Spin

Polarization Experiments," The 4th Joint MMM-Intermag Conference,

Vancouver, British Columbia, Canada, July 14, 1988.

Pierce, D.T., "Experimental Studies of Surface and Thin Film Magnetism

with Polarized Electrons", Physics Seminar, Arizona State University,

October 26, 1987.

Pierce, D.T., "Results from Spin Polarized Electron Spectroscopy of

Surface Magnetism that Puzzle Me," Surface Magnetism Workshop, Laguna

Beach, CA, October 29, 1987.

Pierce. D.T., "Experimental Studies of Surface and Thin Film Magnetism

with Polarized Electrons," Surface Science Seminar, Rutgers University,

May 10, 1988.

Pierce, D.T.

,

"Prospects for a Spin Sensitive STM," Research Advisory

Committee Seminar, National Bureau of Standards, Gaithersburg, MD, May

20, 1988.

Pierce, D.T., "Recent Advances in Compact, Efficient Spin Polarization

Analyzers," Workshop on Polarized Electron Sources and Polarimeters in

Conjunction with the 8th International Symposium on High Energy Spin

Physics, University of Minnesota, Minneapolis, MN, September 8, 1988.

Pierce, D.T., "Quest for Higher Spin Polarization Semiconductor

Photocathodes," Workshop on Polarized Electron Sources and Polarimeters

in Conjunction with the 8th International Symposium on High Energy Spin

Physics, University of Minnesota, Minneapolis, MN, September 9, 1988.

Saloman, E.B., "National Bureau of Standards Data Base of Photon

Absorption Cross Sections From 10 eV to 100 GeV ,

SPIE Conference on Xray and Vacuum Ultraviolet Interaction Data Bases, Calculations, and

Measurements, Los Angeles, CA, January 14, 1988.

67
Division 533, Invited Talks (cont'd)

Scheinfein, M.R., "Considerations for Ultimate Attainable Spatial

Resolution in Microanalysis," Joint U.S./ France Workshop on Electron

Beam Induced Spectroscopies at High Spatial Resolution, Aussois, France,

March 14, 1988.

Scheinfein, M.R., "Scanning Electron Microscopy with Polarization

Analysis (SEMPA)," Joint U.S./ France Workshop on Electron Beam Induced

Spectroscopies at High Spatial Resolution, Aussois, 'France, March 15,

1988.

Stroscio, J.A., "Scanning Tunneling Microscopy of Semiconductor

Surfaces," Fifteenth Annual Conference of the Physics and Chemistry of

Semiconductor Interfaces, Asilomar, CA, February 1, 1988.

Stroscio, J.A., "Observation of Single Atom Adsorbates with the Scanning

Tunneling Microscope," American Physical Society March Meeting, New

Orleans, LA, March 21, 1988.

Stroscio, J.A., "STM Applied to Si and GaAs , " RAC Symposium on NBS

Activities in Scanning Tunneling Microscopy, Gaithersburg, MD, May 20,

1988.

Stroscio, J.A., "Scanning Tunneling Microscopy of Adsorbates on Surfaces," Middle Atlantic Regional Meeting of the American Chemical

Society, Millersville University, Millersville , PA, May 25, 1988.

Stroscio, J.A., "Scanning Tunneling Spectroscopy of Single Atoms on Surfaces," Gordon Research Conference on Electron Spectroscopy,

Wolfeboro, NH, July 18, 1988.

Unguris, J., "Scanning Electron Microscopy with Polarization Analysis,"

The Metallurgical Society Fall Meeting, Cincinnati, OH, October 12, 1987.

Unguris, J., "New Uses for Polarized Electrons," Eastern Regional

Electron Spectroscopy Society Meeting, Martin Marietta, Baltimore, MD,

May 10, 1988.

Unguris, J., "Scanning Electron Microscopy with Polarization Analysis - An Update," Greater Washington Area Surface Science Seminar, National

Bureau of Standards, Gaithersburg, MD, May 20, 1988.

68
PUBLICATIONS

Division 533, Radiation Physics

Callcott, T.A.

,

Tsang, K.L., Zhang, C.H., Ederer, D.L., and Arakawa,

E.T., Soft X-ray Emission Spectra and the Bonding of Aluminum, J. de

Physique, Coll. 9, Supp au n°12, Tome 48, C9-1053 (1987).

Callcott, T.A.

,

Tsang, K.-L., Zhang, C.H., Ederer, D.L., and Arakawa,

E.T.

,

Area Detectors for X-ray Spectroscopy, Nucl. Inst, and Meth. A 266 . 578 (1988).

Callcott, T.A.

,

Tsang, K.-L., Zhang, C.H., Ederer, D.L., Clark, C.W.,

Blendell, J.E., Wassdahl, N. , Rubensson, J.E., Bray, G., Mortensson, N.,

Nordgren, J., Nyholm, R. , and Cramm, S., Electronic Density States of

High Temperature Superconductors From Soft X-ray Spectroscopy, Extended

Abstracts for the 1988 Spring Meeting of Materials Research Society,

Reno, NV, April 5-9, 1988. Eds: D.W. Capone, W.H. Butler, B. Batlogg,

C.W. Chu, MRS Publ . EA-14, Pittsburgh, PA, 1988 p 13-16.

Celotta, R.J., Unguris, J., and Pierce, D.T., Scanning Electron

Microscopy with Polarization Analysis - SEMPA, Proceedings of the 45th

Annual Meeting of the Electron Microscopy Society of America, 178 (1987).

Celotta, R.J., Levine, J., Editors, Methods of Experimental Physics, 24,

Geophysics, Part A, Laboratory Measurements, Academic Press, (1987).

Celotta, R.J., Levine, J., Editors, Methods of Experimental Physics, 24,

Geophysics, Part B, Field Measurements, Academic Press, (1987).

Celotta, R.J., Robins, J.L., Unguris, J., Pierce, D.T., Jonker, B.T., and

Prinz, G.A., Domain Images of Ultrathin Fe Films on Ag(100) Appl. Phys

.

Lett. 52(22), 1918 (1988).

Celotta, R.J., Unguris, J., and Pierce, D.T., Summary Abstract: Scanning

Electron Microscopy with Polarization Analysis: Studies of Magnetic

Microstructures, J. Vac. Sci. Technol. A6(3) (1988).

Celotta, R.J., Advances in Microscopy: Scanning Tunneling and Electron

Polarization Microscopy, Appl. Surf. Sci. 31, 59 (1988).

Cubaynes, D., Bizau, J.M., Wuilleumier, F.J., Ederer, D.L., Picque,

J.L., Carre, B., Ferray, M. , and Gounand, F. , The Main Phases of

Development in Photoemission Studies on Laser- Excited Atoms Using

Synchrotron Radiation, Journal De Physique, Coll. C9 , Supp. no 12, Tome

48, C9-453 (1987).

69
Division 533, Publications (cont'd)

Cutkosky, R.D., Frequency Dependencies of Precision Resistors, Rev. Sci.

Instrum. 59(2), 381 (1988).

Cutkosky, R.D., Precision Weight Calibration with a Specialized Robot,

1988 Measurement Science Conference Proceedings, 271, January 1988.

Dragoset, R.A. and Vorburger, T.V., Scanning Tunneling Microscopy (STM)

of a Diamond- turned Surface and a Grating Replica, SPIE Proceedings 749,

54 (1987).

Ederer, D.L., Canfield, L.R.

,

Callcott, T.A., Tsang, K.-L., Zhang, C.H.,

and Arakawa, E.T., Soft X-ray Absorption and Emission Spectra and The

Electronic Structure of Some Exotic Materials, SPIE Proceedings 911 . 75

(1988)

.

Ederer, D.L., Schaefer, R. , Tsang, K.-L., Zhang, C.H., Callcott, T.A.,

and Arakawa, E.T., Electronic Structure of Icosahedral and Other Phases

of Aluminum-Manganese Alloys Studied by Soft X-ray Emission Spectroscopy

Phys. Rev. B 37, 8594 (1988).

Ederer, D.L., Zhang, C.H., Tsang, K.L., Callcott, T.A., and Arakawa,

E.T., The Al L2 3 and Mg Double Ionization Emission Spectra of Dilute Al

in Mg Alloys, Phys. Rev. B 3_7, 2401 (1988).

Kurtz, R.L., Ederer, D.L., Barth, J., and Stockbauer, R. , Performance of

the SURF- II High-Throughput Toroidal Grating Monochromator, Nucl. Inst,

and Meth. A 266, 425 (1988).

Lucatorto, T.B., Laser Photoionization Spectroscopy book review for IEEE

Jour. Quan. Elect., September 11, 1987.

Matthew, M.A.D., Netzer, F.F., Clark, C.W., and Morar, J.F., Giant 4p

Quadrupole Resonances in the Rare Earths, Europhysics Letters 4, 677

(1987).

McClelland, J.J., Scholten, R.E., Kelley, M.H.

,

and Celotta, R.J., Spin

Sensitivity of a Channel Electron Multiplier, Rev. Sci. Instrum. 59(3),

506 (1988).

Pierce, D.T.

,

Klebanoff, L.E., Jones, R.K., and Celotta, R.J., Spinresolved Inverse-Photoemission Study of Ni(001) and its Chemisorption,

Phys. Rev. B 36(15), 7849 (1987).

Pierce, D.T., Experimental Studies of Surface Magnetism with Polarized

Electrons (Proc. of European Conf. on Surface Science), Surf. Sci. 189-

190, 710 (1987).

70
Division 533, Publications (cont'd)

Pierce, D.T., Celotta, R.J., Kelley, M.H., and Unguris, J., Electron Spin

Polarization Analyzers for Use with Synchrotron Radiation, Nucl. Inst. &

Meth., A266, 550 (1988).

Pierce, D.T. , Unguris, J., and Celotta, R.J., High Resolution Imaging of

Magnetization, Materials Research Society, MRS Bulletin 13(6), 19 (1988).

Penn, D.R., Tanuma, S., and Powell, C.J., Proposed Formula for Electron

Inelastic Mean Free Paths Based on Calculations for 31 Materials, Surf.

Sci. 192, L849 (1987).

Penn, D.R., Tanuma, S., and Powell, C.J., Dependence of Electron Mean

Free Paths on Electron Energy and Material, Proceedings of Analytic

Electron Microscopy Conference, 365 (1987).

Penn, D.R., Electron Mean Free Path Calculations Using a Model Dielectric

Function, Phys . Rev. B35, 482 (1987).

Penn, D.R., Tanuma, S., and Powell, C.J., Summary Abstract: Dependence of

Inelastic Electron Mean Free Paths on Electron Energy and Material, J.

Vac. Sci. Technol., A6(3) , 1041 (1988).

Penn, D.R. , Allen, P.B., and Cohen, M.L., Total Dielectric Function:

Algebraic Sign, Electron-Lattice Response, and Superconductivity, Phys.

Rev. B, 38, 2513-2525 (1988).

Saloman, E.B., Effects of Configuration Mixing in Ml and E2 Transitions

Between Ground-State Terms of Sulfur-Like Ions, Phys. Rev. A .38, 577

(1988) .

Saloman, E.B., Hubbell, J.H., and Berger, M.J., National Bureau of

Standards Data Base of Photon Absorption Cross Sections From 10 eV to 100

GeV, SPIE Proceedings, 911, 100 (1988).

Saloman, E.B., Hubbell, J.H., and Scofield, J.H., X-ray Attenuation Cross

Sections for Energies 100 ev to 100 keV and Elements 5=1 to Z=92 , Atomic

Data and Nucl. Data Tables 38, 1 (1988).

Tsang, K.-L., Zhang, C.H., Callcott, T.A., Canfield, L.R., Ederer, D.L.,

Blendell, J.E., and Clark, C.W., Soft X-ray Absorption and Emission

Spectra of the YBa2 Cu3 07

_ x Superconductor, Proceedings of the First

Drexel Conference on Superconductivity, World Scientific, Singapore 1988.

71
Division 533, Publications (cont'd)

Tsang, K.-L., Zhang, C.H., Callcott, T.A., Canfield, L.R., Blendell, J.,

Ederer, D.L., Clark, C.W., Wassdahl, N., Rubensson, J.E., Bray, G.,

Mortensson, N. , Nordgren, J., Nyholm, R. , and Cramm, S., Soft X-ray

Absorption and Emission Spectra and The Electronic Structure of the

YBa2 Cu3 07

_ x Superconductor, J. de Physique, Coll. C9 , supp an n°12, Tome

48, C9-1193, (1987).

Tsang, K.-L., Zhang, C.H., Callcott, T.A., Canfield, L.R., Blendell, J.,

Ederer, D.L., Clark, C.W., Wassdahl, N., Rubensson, J.E., Bray, G.,

Mortensson, N., Nordgren, J., Nyholm, R. , and Cramm, S., Soft X-ray

Absorption and Emission Spectra and The Electronic Structure of the

YBa2 Cu3 07

_ x Superconductor, Phys . Rev. B. 37 . 2293 (1988).

Unguris, J., Celotta, R.J., Pierce, D.T., and Hembree, G.G., Magnetic

Microstructure Imaging Using Scanning Electron Microscopy with

Polarization Analysis, Proceeding of Analytical Electron Microscopy

Conference, 350 (1987).

Wen, J., Travis, J.C., Lucatorto, T.B., Johnson, B.C., and Clark, C.W.,

Measurement of Isotope Shifts of Two Photon Transitions in Beryllium,

Phys. Rev. A. 37, 4207 (1987).

72
PUBLICATIONS IN PREPARATION

Division 533, Radiation Physics

Armentrout, C.J., Geddes, J.B., Lee, P. , Snider, R.T., and Canfield,

L.R.

,

UV to SXR Surveys Using a Compact, Biplanar Diode Array (to be

submitted, Proc . of the Seventh International Conference on High

Temperature Plasma Diagnostics)

.

Bengtsson, L. , Travis, J.C., Lucatorto, T.B., Kreider, K. , and Brown, L.

,

Laser Ablation of Thin Films as a Free Atom Source for Pulsed Rims (to be

published, Proc. of the Fourth International Conf. on Resonance

Ionization Spectroscopy and Its Applications, 1988).

Cooper, J.W., Clark, C.W.

,

Cromer, C.R., Lucatorto, T.B., Sonntag, B.F.,

Kennedy, E.T., Costello, J.T., Junwen, C., and Tomkins, F.S.,

Autoionizing Resonaces in Mn, Mn+, and Cr 3p Subshell Absorption (to be

submitted, Phys . Rev. Lett.).

Furst, M.L. and Madden, R.P., SURF-II Radiometric Instrumentation

Calibration Facility (to be submitted to SPIE Proceedings, 982 )

.

Korde, R. , Canfield, L.R., and Wallis, B. , Stable, High Quantum

Efficiency Silicon Photodiodes for Vacuum-UV Applications, SPIE

Proceedings 932 )

.

McClelland, J.J., Scheinfein, M.R., and Pierce, D.T., Use of Thorium as a Target in Electron Spin Analyzers (to be submitted, Rev. Sci. Instrum.).

Pan, L. , Taylor, K.T., and Clark, C.W., Computation of the A.C. Stark

Effect in the Ground State of Atomic Hydrogen (to be submitted, Phys.

Rev. Lett . )

.

Penn, D.R., Tanuma, S., and Powell, C.J., Calculations of Electron

Inelastic Mean Free Paths for 31 Materials (to be published, Surface and

Interface Analysis)

.

Penn, D.R., Chang, K.J., and Cohen, M.L., Electronic Correlations and

Satellites in Superconducting Oxides (to be published, Phys. Rev. B)

.

Penn, D.R. and Apell, P., Free Electron Like Stoner Excitations in Fe

(to be published, Phys. Rev. B)

.

Saloman, E.B., A Resonance Ionization Spectroscopy/Resonance Ionization

Mass Spectrometer Data Service (to be published, Proc. of the Fourth

International Conference on Resonance Ionization Spectroscopy and Its

Applications, 1988).

73
Division 533, Publications in Preparation (cont'd)

Saloman, E.B., Energy Levels and Transition Probabilities in the Ground

State Configuration of Sulfur-Like Ions (to be published, Atomic Data

and Nuclear Data Tables)

.

Scheinfein, M.R., Pierce, D.T., Unguris, J., McClelland, J.J., and

Celotta, R.J., Improved Low-Energy Diffuse Scattering Electron- Spin

Polarization Analyzer (to be submitted, Rev. Sci. Instr.).

Scheinfein, M.R., Unguris, J., Pierce, D.T., and Celotta, R.J., Scanning

Electron Microscopy with Polarization Analysis (SEMPA) : High Spatial

Magnetic Imaging Status Report (to be published, Proc . of Aussois

Workshop on Electron Beam Induced Spectroscopies at High Spatial

Resolution, March, 1988).

Wassdahl, N., Rubensson, J.E., Bray, G., Rindstedt, J., Martensson, N.,

Nordgren, J., Nyholm, R. , and Cramm, S., Cu L and 0 K Emission Spectra of

the YBa2 Cu2 07 _ x Superconductor Excited by Monochromatized Synchrotron

Radiation (to be submitted, Physics Letters).

74
TECHNICAL AND PROFESSIONAL COMMITTEE PARTICIPATION AND LEADERSHIP

Division 533, Radiation Physics

Robert J. Celotta

Member, General Committee, International Conference on the Physics

of Electronic and Atomic Collisions.

Member, NML EEO Committee, 1986-88.

Charles W. Clark

Member, National Research Council Committee on Line Spectra of the

Elements - Atomic Spectroscopy.

Co-director, NATO Advanced Study Institute "Atoms in Strong Fields."

Member, Ad Hoc Committee on Page Charge Analysis, Optical Society of

America

.

Thomas B. Lucatorto

Co-chairman, 1989 International Conference on the Physics of

Electron and Atomic Collisions.

Member, Program Committee, 4th International Symposium on Resonance

Ionization Spectroscopy and its Applications, 1988.

Co-chairman, Local Organizing Committee, 4th International Symposium

on Resonance Ionization Spectroscopy and its Applications, 1988.

Robert P. Madden

Member, Optical Society of America Nominating Committee.

Member, Calibration and Stability Working Group of the Ozone Trends

Panel

.

Coordinator, International Radiometric Intercomparison of Solar

Irradiance Experiments.

Member, International Committee for the International Conference on Vacuum Ultraviolet Radiation Physics.

Member, Council of U.S. Synchrotron Radiation Laboratory Directors.

75
Division 533, Technical and Professional Committee Participation (cont'd)

Member, International Committee of the International Conference on X-ray and VUV Synchrotron Radiation Instrumentation.

Member, Synchrotron Radiation Facility Working Group (Department of

Energy)

.

Member, NBS-NML Classification Committee for the NBS Personnel

Demonstration Project.

Stanley R. Mielczarek

Member, NBS Property Review Board

William R. Ott

Member, International Working Group for Middle Atmospheric Program

on Solar Spectral Irradiance Measurements, 1981-1988.

Member, Local Organizing Committee for the 4th International

Symposium on Resonance Ionization Spectroscopy and Its Applications,

1987-88.

Chairman, NBS-CRR Calibrations Advisory Committee, 1985-88.

Member, NBS-NML Classification Committee for the NBS Personnel

Demonstration Project, 1987-88.

Daniel T. Pierce

Member, Editorial board, Journal of Electron Spectroscopy.

Chairman, 1988 Gordon Conference on Electron Spectroscopy.

Chairman, Executive Committee, Surface Science Division of American

Vacuum Society, 1988.

Program Chairman, 1987 American Vacuum Society (Surface Science

Division) Meeting in Anaheim.

76
MAJOR CONSULTING AND ADVISORY SERVICES

Division 533, Radiation Physics

L.R. Canfield consulted with Raj Korde of United Detector Technology on applications of silicon photodiode detectors in the far ultraviolet.

L.R. Canfield consulted with Obert Wood and William Silvfast of AT&T Bell

Laboratories and David Nilson of the Lawrence Livermore National

Laboratory on aluminum thin film filters for x-ray laser applications.

L.R. Canfield consulted with Charles Armentrout and Joseph Geddes of KMS

Fusion on narrow band detectors and filters for the far uv and soft x-ray

regions

.

L.R. Canfield consulted with Fred Hererro and Walter Hoegy of the Goddard

Space Flight Center on the photoemission of materials on board a Venus

orbiter spacecraft.

L.R. Canfield advised production personnel at Science Applications

Corporation and Ball Aerospace Systems on photoemissive detectors for the

vacuum ultraviolet.

L.R. Canfield advised A.L. Lane of the Jet Propulsion Lab on problems

associated with detectors for space applications.

L.R. Canfield advised Howard Ogawa of Southern California University and

Gary Rottman of the University of Colorado on the use of a narrow-band

detector for solar flux measurements in a rocket flight.

C. W. Clark advised a group at Princeton Plasma Physics Laboratory on

atomic physics problems associated with x-ray laser development.

R.J. Celotta and D.T. Pierce consulted on the production and detection of

polarized electrons with researchers from Brookhaven, AT&T Bell Labs,

Bell Communications Corporation, University of Texas, MIT, Argonne

National Laboratory, Perkin Elmer Corporation, and the Naval Research

Laboratory

.

D. L. Ederer consulted with Denise Caldwell of the University of Central

Florida on angular distribution of fluorescence radiation in helium.

D.L. Ederer consulted with Richard Freeman of AT&T Bell Labs on pumpprobe experiments involving lasers and synchrotron radiation.

77
Division 533, Major Consulting and Advisory Services (cont'd)

R.P. Madden consulted for NASA by serving on the "Spacecraft Instrument

Calibration and Stability" Working Group of the "Ozone Trends Panel"

contributing to the report to Congress entitled "Present State of

Knowledge of the Upper Atmosphere 1988: An Assessment Report" as required under the Clean Air Act Amendments of 1977, Public Law 95-95.

R.P. Madden, at the request of the Director of the Earth Science and

Applications Division of the Office of Space Science and Applications,

NASA, is coordinating an international round-robin intercomparison of

solar irradiance monitoring space experiments.

R.P. Madden is on a Naval Research Laboratory advisory panel reviewing

national programs in lithography research.

W.R. Ott consulted with scientists from Lockheed Corporation and several

DoD organizations on measurement needs for remote sensing applications

with ultraviolet and soft x-ray radiation.

M.R. Scheinfein and M.H. Kelley consulted with NSLS staff at Brookhaven

National Laboratory on spin-polarized angle-resolved photoelectron

spectroscopy

.

J. Unguris, M.R. Scheinfein, and M.H. Kelley consulted with the Physical

Electronics Division of Perkin Elmer Corporation on commercialization of

a SEMPA microscope.

78
JOURNAL EDITORSHIPS

Division 533, Radiation Physics

R.J. Celotta, Series Editor, Methods of Experimental Physics.

C. W. Clark, Topical Editor for Atomic Spectroscopy, Journal of the

Optical Society of America B.

D. T. Pierce, Editorial Board, Journal of Electron Spectroscopy.

79
TRIPS SPONSORED BY OTHERS

Division 533, Radiation Physics

R.J. Celotta presented a talk at the Australian Bicentenary Congress,

Sydney, Australia, January 26, 1988.

C.W. Clark gave a Quantum Electronics Seminar at the State University of

New York, Stony Brook, NY, October 30, 1987.

D.L. Ederer presented a talk at the University of Notre Dame, South Bend,

IN, October 15, 1987.

D.L. Ederer gave a lecture at the Naval Postgraduate School, Monterey,

CA, January 8, 1988.

D.L. Ederer presented at talk at the University of California, Riverside,

CA, January 12, 1988.

D.L. Ederer presented a talk at the University of Southern California,

Los Angeles, CA, January 13, 1988.

D.L. Ederer presented at talk at Argonne National Laboratory, Argonne

,

IL, June 17, 1988.

J.J. McClelland gave a Physics Colloquium at Wesleyan University,

Middletown, CT, October 1, 1987.

J.J. McClelland gave a Physics Colloqium at University of Kentucky,

Lexington, KY, October 21, 1987.

D.R. Penn gave a Physics Colloquium at Rice University, Houston, TX,

January 26, 1988.

D.R. Penn presented a colloquium at Chalmers University, Chalmers,

Sweden, April 15, 1988.

D.R. Penn gave an invited talk at The 4th Joint MMM- Intermag Conference,

Vancouver, British Columbia, Canada, July 14, 1988.

D.T. Pierce gave a Physics Seminar at Arizona State University, October

26, 1987.

D.T. Pierce gave an invited talk at the Surface Magnetism Workshop,

Laguna Beach, CA, October 29, 1987.

D.T. Pierce gave a Surface Science Seminar at Rutgers University, May

10, 1988.

80
Division 533, Trips Sponsored by Others (cont'd)

M.R. Scheinfein gave a talk at the Joint U.S./ France Workshop on Electron Beam Induced Spectroscopies at High Spatial Resolution, Aussois

France, March 15, 1988.

M.R. Scheinfein gave a talk at the Joint U.S./ France Workshop on Electron Beam Induced Spectroscopies at High Spatial Resolution, Aussois

France, March 15, 1988.

J.A. Stroscio gave an invited talk at the 15th Annual Conference of the

Physics and Chemistry of Semiconductor Interfaces, Asilomar, CA,

February 1, 1988.

81
CALIBRATION SERVICES PERFORMED

Division 533, Radiation Physics

Tvoe of Service

Customer

Tvne*

SP 250

Item No.

Number

Calibration

or Tests

Far UV radiometric

transfer standard

detectors (photodiode calibrations)

1,4-8 N.A. 39

Spectrometer cali- 5-7

brations using SURF

as an absolute source

N . A. 12

Totals 51

* Column 2: 1, calibration labs; 2, hospitals; 3, nuclear energy

establishments; 4, industry; 5, US government labs; 6, DoD

labs; 7, universities; 8, foreign governments.

82
SPONSORED SEMINARS AND COLLOQUIA

Division 533, Radiation Physics

Abraham, Daniel T. , University of California at Irvine, "Spin Dependent

Elastic and Elastic Scattering from Magnetic Surfaces," March 14, 1988.

Apell, Peter, Chalmers University of Technology, Sweden, "De-Excitation

of Multiply Charged Ions," February 19, 1988.

Bartschat, Klaus, Universitat Munster, West Germany, "Excitation and

Ionization of Atoms by Electron and Photon Impact," February 29, 1988.

Bashkansky, Mark, Columbia University, "Review of Recent ATI Experimental

Results," December 11, 1987.

Bentley, Murry, Johns Hopkins University, "Fully Variational Hartree-Fock

Calculations of Quasi-Bound Atomic States," June 8, 1988.

Bruhwiler, Paul, University of Virginia, "Charged Density Waves in Alkali

Metals," April 1, 1988.

Cadez, Iztok, Institute of Physics, Belgrade, "Vibrational Excitation of

Hydrogen via Recomb inative Desorption of Atomic Hydrogen Gas on a Metal

Surface," December 3, 1987.

Clark, R.N., University of Washington, "Chaotic Behavior of a Simple

System," December 29, 1987.

Delos, John, College of William and Mary, "Atoms in Strong Fields:

Quantum Manifestitations of Classical Order and Classical Chaos," June 3,

1988.

Dreyfuss, Russell, IBM T.J. Watson Research Labs., Yorktown Heights,

"Laser Probing of Laser Ablation," November 17, 1987.

Dutcher, John, Simon Fraser University, "Brillouin Light Scattering

Studies of Magnetic Surface Anisotropy," June 3, 1988.

Fairbank, William, Colorado State University, "Photon Burst Mass

Spectrometry," November 4, 1987.

Falcone, Roger, University of California (Berkeley), "New Short Pulse XRay Sources From Laser Heated Solids," July 6, 1988.

Garton, W.R.S., Imperial College, "Atoms in High External Fields,"

January 12, 1988.

83
Division 533, Sponsored Seminars and Colloquia (cont'd)

Garton, W.R.S., Imperial College, "External Field Effects in Atomic

Spectra," November 17, 1987.

Glab, Wallace, Argonne National Laboratory, "Highly Excited States of

Molecular Hydrogen in a Strong Electric Field," June 27, 1988.

Greene, Chris, Louisiana State University, "Two-electron Excitations in

Atomic Ca," March 30, 1988.

Lefebvre-Brion, H., Universite de Paris-Sud, "Autoionization and

Photodissociation in Diatomic Molecules: Application to 02 and HCI

Molecules," August 4, 1988.

Liebsch, Angskar, Institute Theoretical Physics, KFA-Julich, West

Germany, "Linear and Nonlinear Response at Metal Surfaces," May 23, 1988.

Liu, Ya-Wen, Beijing University, "Progress at the Beijing Storage Ring

Facility," April 29, 1988.

Izerda, Yves, Naval Research Laboratory, "Stoner Excitations in Magnetic

Thin Films," April 26, 1988.

Livins , Peter, University of Virginia, "Shake-up in Soft X-ray Emission,"

April 5, 1988.

Malafsky, Geoffrey, Penn State University, "Primary Ion Energy Effects in

the Sputtering of Single Crystal Metals," July 7, 1988.

Menendez , Manuel, University of Georgia, "Fast Atomic Collisions: A

Pathway to the Three Body Coulomb Problem," July 11, 1988.

Mundschau, Michael, Technischen Universitat Clausthal, "Low-Energy

Electron Microscopy," January 19, 1988.

Nayfeh, M.N. , University of Illinois, "Fragmentation and Ionization of

Diatomic Molecules in Intense Laser Fields," May 6, 1988.

Perera, Rupert, Lawrence Berkeley Laboratory, "Soft X-rays in

Multilayers, Present and Future," March 31, 1988.

Pogatshnik, Gerry, Oak Ridge National Laboratory, "In Search of Oxide

Color Center Lasers," May 6, 1988.

Silvera, Isaac, Harvard University, "Spin Polarized Hydrogen: Prospects

for Base Condensation with Lyman-oc Laser Cooling," October 13, 1988.

Scimica, Thomas, University of Hawaii, "Variable Angle X-ray Emission

Spectroscopy: Applications to Transition Metals," April 29, 1988.

84
Division 533, Sponsored Seminars and Colloquia (cont'd)

Starace, Anthony, University of Nebraska, "Electron Correlation Effects

in Nonresonant Multiphoton Ionization Processes," October 15, 1987.

Thompson, Jeffrey, Oak Ridge National Laboratory, "Observation of the Ca

Ion by Photoelectron Spectroscopy," June 9, 1988.

Wasson, David A. , California Institute of Technology, "Many- Electron

Response to Strong Laser Pulses," December 22, 1987.

Weigold, Erich, Flinders University, "Wave Function Mapping in Atoms and

Molecules," July 26, 1988.

Wuilleumier, Francois, LURE, "Recent Developments in Laser-Synchrotron

Expeirments , " April 14, 1988.

85

TECHNICAL ACTIVITIES

Introduction

Division 534, Radiometric Physics

The Radiometric Physics Division (534) of the Center for Radiation

Research is the primary unit within NIST for carrying out the core mission of promoting accurate, meaningful, and compatible optical

radiation measurements in the uv, visible, and ir spectral regions. The

Division:

develops, improves, and maintains the national standards for

radiation thermometry, spectroradiometry , photometry, and

spectrophotometry

;

disseminates these standards by providing measurement services

to customers requiring calibrations of the highest accuracy;

conducts fundamental and applied research to develop the

scientific basis for future measurement services in optical

radiometry

.

In pursuing these goals, the Division is actively engaged in

collaborative efforts with industry, other government agencies,

universities, professional societies, and standards organizations at the

national and international levels.

The restaffing of the Division continued during Fiscal Year 1988.

Robert Booker, Julius Cohen, and Charles Popenoe retired during the year,

Trish Ferret completed her postdoctoral tenure, and William Peifer's

temporary appointment expired. The following joined the Division as new members of our scientific staff (previous association noted in

parentheses)

:

Ms. Clara Asmail (Optical Science Center, Tuscon, AZ)

,

Dr. Christopher Cromer (Atomic and Plasma Radiation Division),

Mr. Edward Hunter (Ionizing Radiation Division),

Mr. Thomas Lusk (General Electric Co., Cleveland, OH),

Mr. James Proctor (University of Maryland, College Park, MD)

,

Dr. Bobbie Roop (University of Texas, Austin, TX)

,

Dr. Ambler Thompson (University of Maryland, Catonsville, MD)

.

With these changes, the Division comprised 31 permanent technical staff

members on September 1. Eleven of these hold doctorate degrees.

87
Division 534, Technical Activities (cont'd)

As detailed in the following, the Division has made important

progress during the year. For example:

The new optical densitometer using heterodyne interferometry and rfattenuation standards has been used at visible wavelengths to measure

spectral transmittances as low as 10" 12 with better than 1% uncertainty,

and is about to be extended into the ir. A program to explore potential

radiometric applications of Rydberg atom detectors is in the planning

stage. The atomic structure of these atoms may allow the convenient

production of absolute photon detectors from the ir region to millimeter

wavelengths

.

The Division is extending its detector research and development

programs to lower light levels and into the uv and near-ir spectral

regions. There has been substantial progress in the development of

stable, sensitive detector packages which can serve as economic transfer

standards for industrial and research applications at the 0.1 to 0.5%

accuracy level. The joint development of a high-accuracy, absolute,

cryogenically cooled, electrically-calibrated radiometer by NIST and the

National Physical Laboratory (U.K.) will become a new national standard

for spectral detector responsivity with an expected accuracy of 0.005%.

The gold-point experiment has produced improved radiation

temperature measurements, and further refinements of this experiment are expected. Apart from its importance for the impending redefinition of

the International Temperature Scale, this effort has demonstrated that

our pyrometric and spectroradiometric calibration services will benefit

from more extensive utilizations of detector technology. The

corresponding upgrading of our calibration facilities is expected to take

place over the next several years.

Intercomparisons have shown conclusively that detector-based

realizations of photometric scales are more precise than our present,

IPTS-68 based scale. Accordingly, we are initiating a long-term effort

to effect a transition of our photometric calibration services to a detector basis. The construction and initial check-out of a new photometric bench for luminous intensity and color temperature

measurements have been completed. Silicon-cell based color temperature

measurements have been validated against FASCAL.

A new ir imaging laboratory is under development to serve as a measurement facility for ambient temperature blackbodies. In the near

future, an ir spectroradiometric capability and an ir imaging camera will

be added to this effort.

88
Division 534, Technical Activities (cont'd)

The new long-wave ir calibration laboratory is nearing completion.

This facility includes a large, cryogenically-cooled calibration chamber

with an absolute cryogenic radiometer having a sensitivity in the

nanowatt region, and will be used for calibrations of low-background ir

blackbodies and as a research tool for ir radiometry at low temperatures.

A new measurement capability for ir spectral transmittance

measurements in the 2.5 to 25 micrometer region has been established.

Sets of fluorescent materials for front- surface measurements have been

developed and will soon be available as new SRM's. Uniform, neutral

diffuse reflectance transfer standards are being developed.

The conceptual design of the Division's new facility for measuring

bidirectional scattering distribution functions has been completed. The

construction of the facility is planned in fiscal year 1989.

The detailed progress reports for the Spectral Radiometry,

Spectrophotometry, and Measurement Services Groups of the Division appear

below, followed by a summary of our program plans for the new fiscal

year

.

Spectral Radiometry (A. C. Parr, Group Leader)

The Spectral Radiometry Group is responsible for thermal radiometry,

photodetector research and calibration, advanced radiometry research and

applications, and facilities development for the Division. Included in

the latter project area is the development of a facility for calibration

and research in the low background infrared region, and participation in

the development of a new capability for bidirectional scattering

measurements. New programs in thermal imaging and in uv photodetector

research have been initiated. The efforts will extend the calibration

capabilities of the Division and will result in new research and

development directions for the future. The detailed reports on the

projects in the group are given below.

Photodetector Metrology (Zalewski, Thomas, Houston, Eppeldauer)

Our capabilities for detector calibrations have been expanded and

improved in two ways. (1) Greater accuracy has been achieved over the

range from the near uv to the near ir by using the light trapping, multidetector technique and reasonably simple models of the reflectance and

internal quantum efficiency of the Si photodiodes. (2) Based on earlier

89
Division 534, Technical Activities (cont'd)

work, the absolute external and internal quantum efficiencies of several

types of InGaAs and Ge photodiodes have been measured at 1.15, 1.32, and

1.52 micrometers; thereby extending our calibration capability to cover

what is sometimes called the "germanium region".

Using laser lines at 488 and 633 nm, Thomas has studied the

stability of hermetically sealed, radiometric quality p-n silicon

photodiodes. In order to avoid the interference effects found in

commercial windowed silicon photodiodes, a device was constructed using a wedged quartz window with the p-n photodiodes sealed in dry nitrogen.

This device was compared with one of the unsealed, n-p photodiode,

commercially available QEDs (100% quantum efficient devices) that are used as our absolute standard detectors. Over a seven-month period these

two very different devices have been observed to have a constant ratio of

responsivity to within 150 ppm.

An intercomparison in the ir region has been completed with two

other optical radiation measurement laboratories. Pyroelectric

radiometer responsivity at 1.32 micrometers was intercompared with the

fiber optics characterization group at the NIST Boulder Laboratory. An

intercomparison with germanium photodiode responsivity at 1.15, 1.32 and

1.52 micrometers was made with the detector radiometry group at the

Physikalisch Technische Bundesanstalt (FRG) . The level of agreement was within 0.5% in both intercomparisons.

The high accuracy range of the QEDs has been extended from its

former limits of 400 and 700 nm, to 250 and 900 nm, respectively. A

method for determining the reflectance loss of a multi-detector light

trapping radiometer by measuring the individual photocurrents has been

developed. This technique enables an accurate uv extension of the

absolute responsivity of a commercial QED that has been modified to allow

the photocurrent from each photodiode to be read separately. For a multi-detector device employing p-n silicon photodiodes suitable for long

wavelength operation, the accurate absolute responsivity range can be

extended to the near ir.

Houston has completed a detector responsivity comparison with

Canfield of the Radiation Physics Division of CRR. In the spectral range

where both calibration techniques overlap, 250 to 300 nm, the agreement

was within 1%. This was much less than the combined uncertainty estimate

for the two different calibration techniques.

Eppeldauer studied a variety of amplifier/detector combinations and

found one that has a sub- femtoampere noise level. Eppeldauer, Thompson,

and Zalewski used ir devices to measure the absolute spectral radiance of

several different low level, radioactively stimulated fluorescent

samples

.

90
Division 534, Technical Activities (cont'd)

Several more low noise amplifier/detector packages are being

constructed. One will replace the photomultiplier in the gold-point

experiment at certain wavelengths. The others will be used in future

developments in the photometric calibration program.

Work is continuing on the calibration of two types of silicon

photodiodes which will jointly cover the spectral range from 250 to 1100

nm. These photodiodes were selected on the basis of their improved

performance, as compared to the photodiodes presently used in the DRTIP

radiometers. In contrast to the rental approach of the DRTIP program,

the new detector calibration program will consist of a calibrated

detector sold outright to the customer. We are now also in a position to

offer, as a special test, calibrations both in the near ir on radiometric

quality InGaAs or germanium photodiodes and in the visible on spatially

uniform, photopically corrected, radiometric quality silicon photodiodes.

Advanced Radiometry (Hardis, Peifer, Ferrett)

This effort includes the Kr+ ion charge-exchange light source development and collaborative projects using synchrotron radiation to

probe molecular structure and dynamics. The Kr+ project studies the

formation of metastable Kr during charge -exchange collisions of Kr+ ions

upon rubidium vapor. The krypton beam, after charge exchange, can be

laser-excited into an atomic state that decays with equal photon flux in

both the uv and near-ir. Alternatively, the metastable beam can be

reionized and the process used as isotopically selective process for mass analysis

.

This project also includes the Angle Resolved Photoelectron

Spectroscopy (ARPES) experiments conducted at the NIST Synchrotron

Ultraviolet Radiation Facility (SURF-II) and Synchrotron Radiation Source

(SRS) at Daresbury Laboratory in the UK. These studies use the tunable,

narrow-band uv radiation available from synchrotrons along with highresolution electron spectrometers to measure photoemission processes to

gain insights on molecular ionization dynamics. Our research is done

with the cooperation of leading theorists in the U.S. and Europe, who

must often pace their efforts by the availability and quality of

experimental information.

During FY88, the design and construction of the Kr+ project

components was nearly completed. The Colutron ion source initially

showed very poor beam qualities, which were resolved by modifying the

lens and support components. A sample-gas feed system for the ion source

was built, as were beam-line components such as a charge -exchange cell.

The project involves both diode lasers and an argon- ion pumped tunable

91
Division 534, Technical Activities (cont'd)

dye laser. All were made operational. NIST participated in both the DOE

Noble Gas Workshop and the RIS-88 Conference, in which researchers with

similar goals presented their methods and progress. Dr. William R.

Peifer, a postdoctoral scientist, was hired in October to work

exclusively on this project. He left in March to pursue other interest.

Dr. Chris L. Cromer joined the project from Atomic and Plasma Radiation

Division (531) later in the year and made major contributions. Drs

.

Migdall and Hardis collaborated in this work as well.

The ARPES project concluded its long standing run at SURF and was shipped to SRS , where it is being reassembled. Before leaving NIST,

experiments which studied autoionization features and vibronic coupling, were completed on C02 , CO, and N2 0 targets. The principal NIST

investigators were Drs. Trish Ferrett, Steve H. Southworth, Albert C.

Parr, and Jonathan E. Hardis.

Laser Spectrometry (Migdall, Zheng)

A laser heterodyne detection method is being developed to measure

densities of optical filters over as many as 11 orders of magnitude with

an absolute accuracy of about 1%. This technique allows the

transmittance of optical filters to be compared to the electrical

attenuation of an RF attenuator. Using this scheme, the accuracy of the

RF attenuator calibrations can be transfered into the optical

measurements. These methods to make the elctrical measurements are being

improved to allow the accuracy needed to use the full potential of the

technique. The current work has been done at a fixed wavelength of 632

nm, but a tunable dye laser has been demonstrated to work with the

system, allowing for wide tunability. In addition, a C02 laser has

recently been acquired and set up, with the necessary optical system to

follow shortly. The 10.6 urn measurements will use the same electronics

system developed for the visible measurements.

Facilities Development (Fowler, Ebner, Proctor, Tobin)

The Low Background Infrared (LBIR) calibration facility (funded by

DoD) is in the final stages of assembly. The room modifications have

been implemented and the vacuum shell installed on it's frame. The major

components have been procured or fabricated as appropriate and test

fitted together. An auxiliary test chamber has been designed and

fabricated for testing of paint and any other components utilized inside

the chamber for outgassing properties. The final assembly and testing is

92
Division 534, Technical Activities (cont'd)

underway along with the software development. The new design water bath

blackbody is assembled and partially characterized and is currently

undergoing final characterization. We have built two in order to keep

one here at NIST as a tie point for the characterization of other room temperature blackbody radiators. Several servo controlled translation

tables have been designed, fabricated and assembled for use in the

FASCAL, pyrometry and high temperature blackbody facilities. Numerous

electronics systems in support of the laser heterodyne, cryogenic

radiometer, detector calibration facilities and various other projects in

the division have been designed, constructed and tested. The design of

the Bidirectional Scattering Distribution Function (BSDF) apparatus is

underway and progressing rapidly. A new alignment fixture and modified

lamp base assembly has been designed for the spectral flux lamp project

and are currently being tested and evaluated.

Thermal Radiometry Project (Saunders, Southworth, Hillard, Oroshnik)

This project is organized in two areas. The first area is to

determine the freezing point of gold and how it relates to the IPTS-68

temperature scale. The experiment to measure the freezing point of gold

was redesigned to incorporate more accurate silicon detectors which have

recently become available. A detector amplifier package to measure 10’ 15

amperes was developed to replace the photomultiplier on the spectrometer.

The problem of accurate area measurements of apertures was reviewed with

advice from the Precision Engineering Division. The outcome of this

research will yield apertures made on new state of the art grinding

machines with errors of less then .1%. An experiment to intercompare the

resistance temperature scale and optical radiation temperature scale has

been designed and is presently underway. An investigation of the

commercial, scientific and defense needs in pyrometry was carried out.

Preliminary results indicate possible new technology to pursue and

improve pyrometry to meet the nation's needs. Detailed programs to

support pyrometry are being formulated.

The second area of this project is focused on developing a thermal

imaging facility. The facility was put into operation this year and its

first goal is to characterize a uniform, constant temperature, water bath

blackbody (a new standard developed by the Division) . This water bath

blackbody has been characterized at a few wavelengths and the full

characterization will be completed this year. This blackbody has a possible future use in characterizing thermal imaging cameras. An

additional component of this project which is just getting underway is an effort to evaluate thermal radiometers used in the field by the Navy and

Air Force. The medium temperature (400-1000°C) facility was redesigned

and is being rebuilt.

93
Division 534, Technical Activities (cont'd)

Spectrophotometry ( J . J. Hsia, Group Leader)

The Spectrophotometry Group is responsible for the establishment and

dissemination of primary measurement scales for transmission and

reflection spectrophotometry, densitometry, and spectrofluorimetry , and

for the development of methods for the radiometric characterization of

optical components and materials. For these purposes, the Group:

develops and maintains reference instrumentation for performing

spectrophotometric measurements of the highest accuracy;

• develops methodologies for highly accurate spectrophotometric

measurements

;

publishes critically evaluated reference data on intrinsic

standards for spectrophotometry;

provides transfer standards, measurement quality assurance

programs, and special calibrations as needed to support the

national measurement system for spectrophotometry.

The FY88 accomplishments of the Group in three key areas are presented

below.

UV-VIS-NIR-IR SPECTROMETRY

Measurement Services

In FY88 calibration services for industrial laboratories totaling

$20K were performed. Barnes provided special calibration services for

spectral transmittance, specular reflectance, diffuse reflectance, and

opacity. Eckerle provided measurement assurance services for

transmittance. Hunter and Barnes provided NASA with $51K worth of

measurement services for 6 “/hemispherical reflectance and bidirectional

reflectance distribution function. Barnes provided 20 support

measurements for NIST staff outside of this Group, mainly in this

Division. Barnes has batch calibrated sixty, near infrared reflection

wavelength standards for issuance as SRMs

.

Transmittance International Intercomparison

An intercomparison of the regular spectral transmittance scales of

NIST, Gaithersburg, MD (USA); PTB , Braunschweig (FRG) ; NPL, Teddington,

Middlesex (GB) ; and OMH , Budapest (H) was conducted by Eckerle. Three

sets of neutral glass filters with transmittances ranging from

approximately 0.92 to 0.001 transmittance units were used. The

difference between the results from the reference spectrophotometers of

94
Division 534, Technical Activities (cont'd)

the laboratories is generally smaller than the total uncertainty of the

interchange. The relative total uncertainty ranges from 0.05% to 0.5%

for transmittance from 0.92 to 0.001. The contribution to the relative

uncertainty caused by the samples was the limiting factor in the

intercomparison

.

Secondary Standardization Laboratory

Hsia visited the laboratories at the Rochester Institute of

Technology (RIT) , to discuss measurement methods and problems. At RIT's

suggestion, Reiff and Barnes are developing neutral, uniform diffuse

reflectance transfer standards. These standards will be used in

establishing secondary spectrophotometric standardization laboratories.

Transmission Densitometry

Fink has calibrated 270 x-ray step tablets (SRM 1001) and 225

photographic step tablets (SRM 1008) for use in the calibration of

transmission densitometers in the transmission density range 0 to 4 . He

supervised the evaluation of microcopy resolution test charts (SRM

1010a) . Fink has also calibrated two master step tablets in the opalglass scale with the reference transmission densitometer (Inverse Fourth

Instrument). Sinha, Barnes, and Fink completed the hardware installation

and software development for transmission density measurements using a new transfer densitometer and a new microcomputer.

Infrared Spectrometry

Lin has established a new measurement capability for monochromatorbased, regular transmittance in the long wavelength infrared from 2.5 to

25/zm. Four papers related to this work have been prepared for

publication. A 12° specular reflectance sample holder is being

constructed for the monochrator-based spectrometer. Wang has aligned the

optics in the FTIR-based spectrometer to maximize the detector signal.

His wavelength study showed 0.001 cm' 1 stability. He will next

investigate detector linearity and spectrometer inter-reflections.

S PECTROFLUORIMETRY

Eckerle completed the uncertainty analyses for the four fluorescent

materials. Thompson and Eckerle have completed ten measurements on one master set. The corrected emission spectra were measured against one standard lamp. They also completed 5 measurements of one prepared

quinine sulfate SRM. The data are being analyzed and several correction

factors will be applied to check the consistency of the scale. Thompson

95
Division 534, Te'fchncial Activities (cont'd)

has completed measurements on 18 randomly selected sets to check the

reproducibility of batch production. Fifty, corrected emission spectra

SRM sets were completed at the end of FY88.

Thompson and Liu in collaboration with Mr. D. Blackburn and Dr.

Kaufman of Division 420 have initiated some exploratory investigations of

potential materials for future ultraviolet emission spectra SRMs

.

Thompson and Eckerle have completed emission spectral measurements on tritium activated phosphors in a collaborative project with Zalewski.

The emission spectra of two LED have been measured.

BIDIRECTIONAL SCATTERING DISTRIBUTION FUNCTION (BSDF)

Experimental studies were performed prior to the conceptual design

of a BSDF instrument for near- specular samples. The studies included

relative BRDF measurements with different receiver solid angles, light

spot sizes, polarization, and light traps. Proctor, Asmail, and Hsia

have completed the conceptual design which includes mechanical

arrangements of sample mounts, detector mounts, and layout of light sources and optical components.

A filter/diffuser set is being developed to cover BRDF from 0.3 to

10' 7 Sr' 1

. Eckerle has calibrated fourteen neutral density filter

glasses ranging in optical density from 2 to 6 . The measurements were performed at 441.6, 488, 532 and 632.8 nm. Hunter and Barnes have

calibrated 45/0 BRDF on several pressed and sintered PTFE white samples

of about 0.3 Sr' 1 and on several sintered black PTFE samples of about

0.009 Sr' 1

. Hunter has completed some polarization-effect studies on 45/0 BRDF measurements of pressed PTFE powder with density of 1 g cm' 3

. He has also completed the repeatability study of ten pressed PTFE powder

samples for 45/0 BRDF measurements. Three times standard error was 0.3%

of the BRDF value.

Roop has initiated a study to develop approaches to produce near

Lambertian infrared diffusers. She has set-up and tested the C02 laser

system which will be used for heterodyne transmittance and scattering

measurements. Roop also helped trouble shoot the visible heterodyne

system to reduce the noise level in the data.

Hsia has provided consultation in establishing ASTM subcommittee E12.09 on Scattering. The purpose of the Subcommittee is to develop

standard testing methods for scattering measurements including BRDF.

96
Division 534, Technical Activities (cont'd)

Radiometric Measurement Services (D. A. McSparron, Group Leader)

The Group maintains the national scales for radiance temperature,

spectral radiance, spectral irradiance, luminous intensity, luminous

flux, and color temperature. Access to these scales is provided through

29 specific calibration services performed on a routine basis. Research

and development projects are undertaken to extend and improve these

scales. Activities such as intercomparisons (domestic and international), measurement assurance programs, intermediate laboratory

support programs, consultations, special calibrations, and ad hoc

experiments are undertaken to insure that measurements made in

laboratories outside NIST have acceptable levels of accuracy.

Calibration Volume

Direct calibration work was up again in this fiscal year.

Calibration billings for the public increased by 15% and directly

calibration work for other government agencies increased by 34%.

combined effect was an overall increase of 18%.

Detector Based Candela

Andor, in collaboration with the detector and spectrophotometry

projects of the Division, produced and characterized a series of seven photopically-corrected silicon cell photometers. Three of these

photometers were of a novel "trap detector" design. The absolute

spectral response of the photometers was determined by measurements

based on the silicon-self calibration method. This work constituted a detector-based realization of the candela. The cells were compared with

the present blackbody based lamp working standards. The measured

difference was 0.57%. The direction and magnitude of this difference

was such as to confirm the proposed reassignment of the temperature of

freezing gold (a 0.4 K shift in the gold point would shift the present

photometric standards by 0.52%). This result also confirms that the

main contributor to the NIST difference from world mean in the recent

international intercomparison of photometric units was due to a gold

point misassignment

.

Intercomparisons

At the October 1986 meeting of the Consultative Committee on Photometry and Radiometry (CCPR) it was decided to conduct an international intercomparison of national scales of spectral irradiance

with NIST serving as the central laboratory. The wavelength range 250 to

2400 nm was chosen for the intercomparison. Fourteen national

laboratories (in addition to NIST) have agreed to participate. The

National Physical Laboratory (England) is overseeing the construction

funded

The

97
Division 534, Technical Activities (cont'd)

and selection of special lamps for the intercomparison. The selected

lamps, three per participant, were sent to participants in late August

1988. NIST procured and shipped to requesting participants special

sockets and alignment jigs. The participating laboratories are scheduled to make initial measurements in the fall of 1988 and submit

their three lamps to NIST in early December. NIST measurements are expected to be completed by April 1989 and the participants will then

remeasure the lamps. NIST will collect and analyze the data. A report

on the results will be issued for possible action at the next CCPR

meeting in September 1990.

Coordinated with the CCPR intercomparison, an international

intercomparison has been organized among members of the uv solar

monitoring community. The intercomparison will involve spectral

irradiance measurements over the spectral range 200-400 nm. The

intercomparison is scheduled to be carried out over the next 18 months.

A complete workstation containing NIST calibrated uv light sources will

be shipped to each of the labs in turn. Each lab will have the

workstation twice and will use it to calibrate their instruments. The

Radiometric Physics Division is designing and constructing the

intercomparison workstation and will calibrate it at the beginning, in

the middle, and at the end of the intercomparison. The participants in

the intercomparison include the University of Colorado ( SOLSTICE- - Solar

Stellar Irradiance Comparison Experiment) , the Naval Research Laboratory

( SUSIM- - Solar UV Spectral Irradiance Monitor), NASA ( SSBUV- - Shuttle

Solar Backscatter UV Radiometer), a joint Belgian- French group

( SOLSPEC- - Solar Spectrometer), and the Technische Studien Gmbh of West

Germany (ASSI - -Airglow Solar Spectrometer Instrument). These

experiments are of immediate, critical importance to both the scientific

community (atmospheric physics and weather prediction models) and the

general public (ozone monitoring and greenhouse effects)

.

Pyrometry

The upgrade of the radiance temperature calibration facilities

continued this year. Fowler designed a new, automated source bench and

oversaw its construction and installation. The new bench has six source stations and will greatly improve the efficiency of pyrometric strip

lamp calibrations. A new, large area, variable temperature blackbody was received and installed. Check out of this blackbody is now well

underway. When fully characterized, it will allow more convenient

calibration of traditional pyrometers (visual and automatic) and allow

us for the first time to offer a calibration service for pyrometers

operating at wavelengths other than 650 nm. It is planned to establish

a new calibration service for silicon cell based pyrometers in the coming

fiscal year.

98
Division 534, Technical Activities (cont'd)

A special project was carried out by Waters and Walker in support

of the Center for Fire Research (CFR) and the Federal Aviation

Administration. The FAA is developing flammability specifications for

the materials used in commercial airliners. In order to establish a firm measurement base for this flammability testing, CFR procured a commercial, electrically calibrated radiometer (ECR) . Waters and Walker

characterized the linearity and reflectance of this ECR and calibrated

it against the ECR used in the gold point experiment by Saunders.

Several lamp standards of total irradiance were also calibrated to

provide a convenient check procedure as CFR develops measurement

protocols and standards for FAA use.

Photometry

The photometry program received a substantial boost this spring

when Tom Lusk joined the NBS staff after a career of over 30 years as a photometrist/radiometrist in private industry. The combined efforts of

Bruening, Saunders, Lusk, and Hu brought the spectral flux program to a conclusion. This program has provided the U.S. lighting industry with

incandescent and High Pressure Sodium (HPS) lamp standards of

geometrically- total spectral flux. From these lamps industry will

derive spectral and photometric standards for all types of highintensity discharge lamps. These standards will form the basis of a secondary lab support program coordinated through the Lamp Testing

Engineer's Conference (LTEC)

.

Lusk and Wilkinson have continued the work started by Booker to

equip the photometric lab with a modern optical bench. During the year,

a design goal of 0.1% overall accuracy for transfer measurements made on

the new bench was adopted. Andor's measurements in realizing a detector-based Candela were the first experiments making use of this

capability. In the coming year, Lusk and Wilkinson will revamp the

measurement protocols used for the routine photometric calibrations to

place them on a detector base and make use of the capabilities of the new bench.

During the year, Andor carried out a series of experiments to

replace the photomultiplier based color temperature meter with silicon

cells and appropriate filters. Closures with the blackbody-based lamp

standards were better than 5 K (present estimated uncertainties 10-15 K) . In the coming year, Lusk and Wilkinson will incorporate this work into

the routine color temperature calibration service.

Facility for Automatic Spectroradiometric Calibrations (FASCAL)

The routine calibration load on FASCAL, performed by Jackson,

Gibson and Walker, was up substantially, partly because of the support

99
Division 534, Technical Activities (cont'd)

provided to the spectral flux project, and partly due to an attempt to

clear the backlog in anticipation of the intercomparison work planned for

next fiscal year. Modernization of FASCAL continued during the year.

Gibson completed the conversion of the software library to 16-bit,

BETTERBASIC programs. A new lock-in amplifier and a new closed circuit

tv camera were installed. Finally a significant increase in capability

was obtained with the installation of a Fowler designed, extension bench

for two of the source stations. This new bench will allow source to

receiver distances of up to three meter for irradiance work and it will

also permit the operation of base-up sources.

One notable special test was performed during the year. Walker and

Gibson performed a spectral irradiance calibration, 200 to 850 nm, of a special test fixture that was used to calibrated the Faint Object

Spectrograph (FOS) on the space telescope. The FOS will address major

scientific questions associated with quasars, active galaxies, and

normal, distant, and local group galaxies, all within the context of

understanding the origin, structure, composition, and evolution of the

universe

.

Program Plans

The evolution of Division programs has made it desirable to effect

some changes in personnel assignments and group responsibilities which

became effective October 1, 1988.

A new Detector Applications Project is responsible for developing

solid-state detectors for specific applications, commissioning the new NIST/NPL cryogenic radiometer, making further refinements to the

detector-based candela, and providing routine photometric calibrations.

Synergisms between the laser heterodyne and krypton beam experiments have

made it desirable to combine both into a single Advanced Radiometry

project. We have established projects in Bidirectional Scattering

Metrology and Biological Applications of Radiometry, in order to prepare

the Division for a long-term involvement in these rapidly growing areas. A new Infrared Radiometry R&D Project is in the formative stage.

With these changes, the Division will operate under the following

program structure in FY 1989. The project leaders who are responsible

for the day-to-day management of these projects are listed in

parantheses

.

Photodetector Metrology (E. F. Zalewski)

Detector Applications (S. H. Southworth)

Facilities Development ( J . B. Fowler)

Advanced Radiometry (A. L. Migdall)

Infrared Radiometry (to be assigned)

100
Division 534, Technical Activities (cont'd)

Spectrophotometry (K. L. Eckerle)

Bidirectional Scattering Metrology (J. J. Hsia)

Biological Radiometry (A. E. Thompson)

Radiation Thermometry (R. D. Saunders)

Radiometric Measurement Services ( J . H. Walker)

To faciliate the incorporation of detector technology into the

Division's measurement services for radiation temperature, spectral

radiance, and spectral irradiance , the Radiation Thermometry and

Radiometric Measurement Services projects of the Division will be

combined into the new Thermal Radiometry Group, with Robert D. Saunders

as group leader. Donald A. McSparron will oversee the implementation of

detector metrology in all calibration programs within the Division, and

will advise the group and project leaders in the Division who have

calibration responsibilities on questions of scheduling, fiscal

management, quality control, and customer relations. Albert C. Parr will

serve as Deputy Division Chief in addition to his duties as leader of the

Spectral Radiometry Group.

101
INVITED TALKS

Division 534, Radiometric Physics

Eppeldauer, G., Tsudagawa, M. , Zalewski E., Houston, J., Electronic and

Radiometric Characteristics of Near Infrared Photodiodes (13th IMEKO

Symposium on Photonic Measurements, Braunschweig Germany, Fed. Rep.

1987)

.

Ferrett, T. A., Parr, A. C., Southworth, S. H. , Hardis, J. E., and

Dehmer, J. L. , "Vibrationally-Resolved Photoionization Studies of the la

Level in N2 0" , Presented at the Gordern Conference on electron

Spectroscsopy , Wolfsburo, NH, July 18-22, 1988.

Hardis, Jonathan E., Peifer, William R. , Cromer, Chris L. , Migdall, Alan

L. , Snyder, J. J., and Bonanno , R. , "Using 'Resonant' Charge Exchange to

Detect Traces of Noble Gas Atoms", Presented at DOE Noble Gas Workshop,

(March 30 , 1988) .

Hardis, Jonathan E., Peifer, William R. , Cromer, Chris L. , Migdall, Alan

L. , "Using 'Resonant' Charge Exchange to Detect Traces of Noble Gas

Atoms", Submitted to the Proceedings of the Fourth International

Symposium on Resonance Ionization Spectroscopy and its Applications.

(1988).

Hardis, Jonathan E., Ferrett, Trish E., Southworth, Stephen H., and

Dehmer, J. L. , "Triply Differential Photoelectron Studies of

Autoionization in Carbon Monoxide", DAMOP , Boston, MA (1987).

Hsia, Jack J., "Spectrophotometry", CORM'88, National Bureau of

Standards, Gaithersburg, MD , May 18, 1988.

Hsia, Jack J., "NBS Spectrophotmetry Program," Center for Imaging Science

Seminar," Rochester Institute of Technology, NY, April 26, 1988.

Lin, Lin, Hsia, Jack J. "Infrared Spectral Transmittance Measurement,"

CORM '88, National Bureau of Standards, Gaithersburg, MD , May 18, 1988.

McSparron, Donald A., "Photometric Standards", CORM'88, National Bureau

of Standards, Gaithersburg, MD , May 18, 1988.

Mielenz, Klaus D., "NCSL Electro-Optic Measurements Workshop" National

Conference of Standards Laboratories (NCSL) Annual Meeting, Washington,

D.C., August 17, 1988.

102
Division 534, Invited Talks (cont'd)

Migdall, A. L. , Cong, Z. Y. , and Hardis , J. E., "Heterodyne Optical

Densitometry at NBS", Presented at: New Developments and Applications in

Optical Radiometry, Teddington, England, April 12-13, 1988 (to be

published as proceedings)

.

Migdall, A. L. , Cong, Z. Y. , Hardis, J. E., and Snyder, J. J., "An

Optical Heterodyne Densitometer", Proc . of the 2nd Workshop on Improvements to Photometry, NBS, Gaithersburg, MD , October 5-6, 1987.

Parr, Albert C., Ferrett, Trish A., "Photoionization of Small Molecules

Using Synchrotron Radiation", SPIE, Los Angeles, CA (1988).

Parr, Albert C. Fowler, Joel B., and Ebner, Steve, "Low Background

Infrared Calibration Facility at the National Bureau of Standards", SPIE,

Orlando, FL (1988).

Parr, Albert C., Hardis, Jonathan E., Ferrett, Trish E., Southworth,

Stephen H., and Dehmer, J. L. , "Triply Differential Photoelectron Studies

of Autoionization in Carbon Monoxide", DAMOP, Boston, MA (1987).

Parr, Albert C., "Infrared Calibration and Research at NBS", Air Force

Cambridge Laboratory, Hanscom AFB , MA (1988).

Parr, Albert C., "LBIR Calibration Facility at NBS", Arnold Air Force

Station, TN, (April 1988).

Saunders, Robert D., "Spectral Radiometry", CORM'88, National Bureau of

Standards, Gaithersburg, MD , May 18, 1988.

Southworth, Stephen H. , "Triply Differential Photoelectron Studies of

Autoionization in Carbon Monoxide", (poster paper), International

Symposium on Uses of Synchrotron Radiaton in Chemistry, Brookhaven

National Laboratory, Upton, NY, November, 1987.

Southworth, Stephen H., " Photoelectron Spectrometry Studies of Resonant

Molecular Photoionization", Advanced Light Source Users' Association

Meeting, Lawrence Berkeley Laboratory, Berkeley, CA, June, 1988.

Zalewski, Edward, Migdall, Alan, "Characteristics of Germanium and

InGaAs/InP Photodiodes," National Physical Laboratory, Teddington,

England, April 12, 1988.

103
PUBLICATIONS

Division 534, Radiometric Physics

Ferrett, T. A. and Parr, A. C., "Photoionization of Small Molecules using

Synchrotron Radiation", SPIE Vol. 911, p. IS), (1988).

Ferrett, T. A., Parr, A. C., Southworth, S. H., Hardis , J. E., and

Dehmer, J. L. , "Vibrationally-Resolved Photoionization Studies of the 7s

Level in N2 0", Presented at the Spring Meeting of the APS, Baltimore,

MD, April 18-21, 1988, Bull, of the Am. Phys . Soc. 33, 1038 (1988).

Hardis, J. E., Ferrett, T. A., Southworth, S. H., Parr, A. C., Roy, P.,

Dehmer, J. L. , Dehmer, P. M. , and Chupka, W. A., "Autoionization Dynamics

in the Valence-Shell Photoionization Spectrum of C02

"

, J. Chem. Phys. 89 . 812 (1988).

Hsia, J. J., "National Scales of Spectrometry in the U.S.", Analytical

Spectroscopy Library Vol. 2, Advances in Standards and Methodology in

Spectrophotometry (C. Burgess and K. D. Mielenz, editors), Elsevier,

1988.

Mielenz, K. D. and Hsia, J. J., "Division 2 - Measurement of Light and

Radiation," Proceeding of the 21st Session of the Commission

Internationale de Eclairage, in Venice 1987, p.122-124, vol. I and p.38-

41, vol. II

Mielenz, K.D., "International Intercomparisons of Photometric Base

Units," J. of Phys. (National Bureau of Standards), 92 , 335 (1987).

Mielenz, K.D., "Fluorescence Spectrometer in Analytical Chemistry and

Color Sciences," Analytical Spectroscopy Library Vol. 2, Advances in

Standards and Methodology in Spectrophotometry (C. Burgess and K. D. Mielenz, editors), Elsevier, 1988.

Parr, A. C., Hardis, J. E., Southworth, S. H., Feigerle, C. S. Feigerle,

Ferrett, T. A., and Holland, D. M. P., "Vibrationally Resolved

Photoelectron Angular Distributions for H2 in the Range 17 eV < hvn < 39

eV" , Phys. Rev. A 37., 437 (1988).

Parr, A. C., Fowler, J., Ebner, S., "Low Background Infrared Calibraiton

Facility at the National Bureau of Standards," SPIE, Vol. 940, 26 . (1988) .

Parr, A. C., Dehmer, J. L. "Shape Resonance in Molecular Fields,"

Fundamental Processes in Atomic Dynamics . Ed. by J. S. Briggs, H. Kleinpoppen and H. Lutz, Plenum, New York, (1988).

104
Division 534, Publications (cont'd)

Roy, P., Ferrett, T. A., Schmidt, V., Parr, A. C., Southworth, S. H.,

Hardis , J. E. , Bartlett, R. , Trela, W. , and Dehmer, J. L. , "A Study of

the Vibronic Coupling in the C State of C02 +

"

, Journal de Physiques,

colloqoc, C 9 Supplement au n°12, Tome 48, (December, 1987).

Schaefer, A. R. , "Tunable Dye Laser Spectrometry," Analytical

Spectroscopy Library Vol. 2, Advances in Standards and Methodology in

Spectrophotometry (C. Burgess and K. D. Mielenz, editors), Elsevier,

1988.

Southworth, S. H. Parr, A. C., Hardis, J. E , and Dehmer, J. L. , "Resonance Structure in the Vibrationally Resolved Photoelectron

Branching Ratios and Angular Distributions of the 2p' 1 Channel of NO", J.

Chem. Phys. 87, 5125 (1987).

105
PUBLICATIONS IN PREPARATION

Division 534, Radiometric Physics

Andor, G. Temperature Dependence of High Accuracy- Photometer Heads (to be

published Applied Optics Letters)

.

Eckerle, K.L., Sutter, E., Freeman, G.H.C., Andor, G., and Fillinger, L.

,

International Intercomparison for Transmittance (in preparation).

Eppeldauer, G., Long Term Changes of the Self -Calibrated Inversion Layer

Photodiode Used as a Photometric Standard (to be published CIE Journal)

.

Ferrett, T. A., Parr, A. C., Southworth, S. H., Hardis, J. E., and

Dehmer, J. L. , "Vibrationally-Resolved Photoionization Studies of the la

Level in N2 0", (to be published in Journal of Chem. Phys . )

.

Geist, J., Migdall, A., and Baltes, H.P., "Analytic Representation of the

Silicon Absorption Coefficient in the Indirect Transition Region", (to be

published October 1, 1988, Applied Optics).

Hardis, J.E., Peifer, W.R., Cromer, C.L., Migdall, A.L., Parr, A.C.,

Using "Resonant" Charge Exchange to Detect Traces of Noble Gas Atoms (to

be published Proceedings on the 4th International Symposium on Resonant

Ionization and its Applications)

.

Hardis, J.E., Peifer, W.R., Cromer, C.L., Migdall, A.L., Parr, A.C.,

Using "Resonant" Charge Exchange to Detect Traces of Noble Gas Atoms (to

be published Proceedings on the 4th International Symposium on Resonant

Ionization and its Applications)

.

He, M. , Bruening, R.J., High Pressure Sodium Discharge Lamp

Characterization For Use As Standards of Geometrically Total Luminous

Flux (to be published NBS TN)

Hillard, G.B., Nayfeh, M.H., Two-photon Ionization of Potassium in dc

Electric Fields (to be published Phys. Rev. A.).

Lean, J.L., Kostkowski, H.J., Saunders, R.D., Hughey, L.M., Comparision

of the NBS Surf and Argon Mini-Arc Irradiance Standards at Ultraviolet

Wavelengths (to be published, Applied Optics).

Lin, L. , Hsia, J.J., Infrared Spectrophotometer Linearity Measurements

(in preparation).

106
Division 534 Publications in Preparation (cont'd)

Lin, L. , Hsia, J.J., Interreflection Correction for Infrared

Transmittance Measurements (in preparation).

Lin, L. , Hsia, J.J., Infrared Spectral Transmittance Measurements (in

preparation)

.

Migdall, A. L. , Cong, Z. Y. , and Hardis , J. E., "Heterodyne Optical

Densitometry at NBS" , Presented at: New Developments and Applications in

Optical Radiometry, Teddington, England, April 12-13, 1988 (to be

published as proceedings)

.

Saunders, R.D., Kostkowski, H.J., Roughened Quartz Surfaces and Teflon as Small-Angle Diffusers and Depolarizers Between 200 and 400 nm (to be

published, Applied Optics)

.

Thomas, D.B., Zalewski , E.F., A Radiometer for Precision Coherent

Radiation Measurements (to be published, Applied Optics).

107
TECHNICAL AND PROFESSIONAL COMMITTEE PARTICIPATION AND

LEADERSHIP

Division 534, Radiometric Physics

Yvonne Barnes

Member, ASTM E-12 Committee, Appearance of Materials

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

.

Member, CIE TC2-28 on Methods of Characterizing Spectrophotometers.

Laurence E. Fink

NBS Representative, ANSI PH2 on Photographic Sensitometry and PH2-28

on Densitometry

G. Barry Hillard

Member, ASTM E-20 Committee, Temperature Measurement, Subcommittee

E-20-2, Radiation Thermometry

Jack J . Hsia

Director, Inter Society Color Council.

Secretary, CIE Division 2, Physical Measurement of Light and

Radiation.

Chairman, CIE TC 2-11 Technical Committee on Goniophotometry

.

Secretary, U.S. National Committee of the CIE.

Alternate Representative, ANSI PH2 , Photographic Sensitometry, PH2-

28, Densitometry.

108
Division 534, Technical and Professional Committee Participation and

Leadership (cont'd)

Jack Hsia (cont'd)

Member, ASTM E-12 Committee, Appearance of Materials

(Spectrophotometry, Colorimetry, Geometric Properties, and

Scattering)

.

Member, ASTM E-13 Committee, Molecular Spectroscopy; Subcommittee E13.01, Ultraviolet and Visible Spectroscopy; E-13. 03, Infrared

Spectroscopy, and E-13. 06, Molecular Luminescence.

Secretary, CORM/NBS Task Force on Spectrophotometry.

Donald A. McSparron

Member, ANSI Z311, Photobiological Safety of Lamps and Lighting

Systems

.

Member, Illuminating Engineering society (IES) , Testing Procedures

Committee

.

Member, Lamp Testing Engineers' Conference.

Chairman, Tellers Committee, Optical Society of America.

Klaus D. Mielenz

Vice President, U.S. National Committee of the CIE.

Director, CIE Division 2, Physical Measurement of Light and

Radiation

.

Member, ASTM E-13 Committee, Molecular Spectroscopy; Subcommittee

E-13. 06, Molecular Luminescence.

Member, IES Subcommittee C012, Nomenclature.

Exofficio member, CORM Board of Directors

Vice Chairman, CORM Task Force on Spectrophotometry.

Member, OSA International Affairs Committee.

Member, Advisory Board, Munsell Color Science Laboratory, Rochester

Institute of Technology.

109
Division 534, Technical and Professional Committee Participation and

Leadership (cont'd)

Albert Parr

Visiting Senior Fellowship, Aberdeen University, Scotland.

Member, Queen Match Calibration Review for SDC.

Member, Organizing Committee, National Synchrotron Instrumentation

Conference

.

Member, Organizing Committee, Local Co-chairman Chemical Low-Level

Light Detector Conference.

Robert D. Saunders, Jr.

Member, ANSI Z311, Photobiological Safety of Lamps and Lighting

Systems

.

Member, IES Photobiology Committee.

Member, CIE TC2-05, Distribution Temperature.

Douglas B. Thomas

Member, U.S. National Committee of the CIE

Alternate, ASTM E-20 Temperature Measurements

Member, ASTM E44 , Solar Energy Conversion.

Ambler Thompson

Member, Division 6 on Photobiology and Photochemistry, U.S. National

Committee of the CIE.

William R. Waters

Member, ASTM E-20, Temperature Measurement.

Edward F. Zalewski

Chairman, CIE TC2-06, Absolute Spectral Responsivity

.

Member, U.S. National Committee of the CIE.

110
BOOK AND JOURNAL EDITORSHIP

Division 534, Radiometric Physics

Parr, Albert C., Member, Editorial Board, Review of Scientific Instrument

Journal

.

Burgess, C., Mielenz, K. D., Editors, Advances in Standards and

Methodology in Spectrophotometry, Analytical Spectroscopy LibraryVolume 2.
STANDARDS COMMITTEE MEETINGS

CORM Annual

LTEC Spring

Division 534, Radiometric

Meeting, NBS , May 18-19, 1988.

Meeting, NBS, May 17, 1988.

Physics

112
MAJOR CONSULTING AND ADVISORY SERVICES

Division 534, Radiometric Physics

J. J. Hsia provided consultation to B. Guenther of NASA on large area reflectors for bidirectional reflectance measurement problems.

J. J. Hsia provided consultation to D. Rosseler of Research Laboratory,

General Motor Company on specular reflectance calibration procedures.

J. J. Hsia provided consultation to V. Pilskalns and W. Gingrass of

Eastman Kodak Company on infrared spectrophotometry.

R. D. Saunders provided consultation to the Nation Science Foundation on Polar Ozone Measurements.

J. H. Walker provided consultation to personnel from Sandia National

Laboratory on pyrometric calibrations and standards.

J. H. Walker and W. R. Waters provided consultation to the Samuel E. Chappell of the Office of Standards Management on the U.S. position on draft OIML Recommendations for radiation temperature measuring

instruments and standards.

D. A. McSparron provided consultation to G. Subrey of Pacific Safety

Industries and D. Spadone , S. Waits, and D. Laster of the U.S. Navy on testing methods for phosphorescent paints.

D. A. McSparron provided consultation to M. Fecteau, S. Underwood, and C. Bradford of the U.S. Army and S. Parker, J. Terrell, and T. Larason of

the U.S. Navy on measurement methods and standards suitable for testing

Night Vision Imagings Systems (NVIS)

.

D. A. McSparron provided advice to P. Wychorski and V. Pilskalns of

Eastman Kodak Company on means of achieving state of the art accuracy in

photometric measurements.

A. C. Parr provided consultation to the Queen Match Committee of DoD on

low backgound radiometrics problems in and number of project areas.

R. Saunders provided consultation to National Science Foundation on Artie

Ozone Measurements

.

113
STANDARD REFERENCE MATERIALS

Division 534, Radiometric Physics

SRM 1001, X-Ray Film Step Tablet

For calibration of optical densitometers and similar equipment used

in the photographic, graphic arts, and x-ray fields. Certified for

transmission densities from 0 to 4

.

SRM 1008, Photographic Step Tablets

For calibration of optical densitometers and similar equipment used

in the photographic, graphic arts, and x-ray fields. Certified for

transmission densities from 0 to 4

.

SRM 1010a, Microscopy Resolution Tests Charts

For determining the resolving power of microscopy systems.

4.

SRM 2061, Reflection Step Tablets

For calibration of optical densitometers and similar equipment used

in the photographic, graphic arts, and x-ray fields. Certified for

reflection densities from 0 to 2

.

5. SRM 2019 and 2020, White Ceramic Tile for directional-Hemispherical

Reflectance from 350 to 2500 nm. SRM 2021 and 2022, Black Porcelain

Enamel for directional-Hemispherical Reflectance from 280 to 2500

nm. SRM 2015 and 2016, White Opal Glass for directionalHemispherical Reflectance form 400 to 750 nm.

For use in calibrating the reflectance scale of an integrating

sphere ref lectometers

.

6. SRM 2003b, First Surface Aluminum Mirror for Specular Reflectance

form 250 to 2500nm. SRM 2011, First Surface Gold Mirror for

Specular Reflectance form 600 to 2500 nm. SRM 2023, 2024, and 2025

Second Surface Aluminum Mirror for Specular Reflectance form 250 to

2500 nm.

For use in calibrating the photometric scale of specular

ref lectometers

.

7.

SRM 2009, 2010, 2013, 2014 Didymium-Oxide Glass, Wavelength

Standards between 400 and 760 nm.

114
Division 534, Standards Reference Materials (con't)

8. SRM 2034 Holmium oxide in Perchloric Acid Solution as Wavelength

Standards between 241 and 640 run.

9. SRM 1920 Near Infrared Reflectance Wavelength Standards from 740-

2000 run.
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. Retroreflectance 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 retroreflectors and to assess the

conformance to the spectral specification of its

retroref lectometers

.

116
CALIBRATION SERVICES PERFORMED

Division 534, Radiometric Physics

Number of

Tvr>e of Service Customer SP250 tests

Pyrometry

Defense & Aerospace

35010C thru 35070S

10

13

Instrument & Cal labs 1 Electrical & Materials 2

Spectroradiometry - Sources 39010C thru 39060S 38

Defense & Aerospace 17

Instrument & Cal labs 8 Lighting & Photography 6 Foreign 3 Electrical & Materials 4

Spec troradiome try - Detectors 39070C thru 39080S 12

Defense & Aerospace 5 Instrument & Cal labs 5 Lighting & Photography 1 Foreign 1

Photometry

Defense & Aerospace

30701C thru 37180S

15

39

Instrument & Cal labs 4

Lighting & Photography 8 Foreign 4

Electrical & Materials 8

Spectrophotometry

Defense & Aerospace

38010C thru 38100S

3

19

Instrument & Cal labs 7 Lighting & Photography 2 Foreign 1 Electrical & Materials 6 121

117
TRIPS SPONSORED BY OTHERS

Division 534, Radiometric Physics

J. Houston, NBS-PTB Scientist Exchange, sponsored by PTB to stay and work

at the Braunschweig location from April 18 to June 16, 1988.

S. Southworth, to set up ARPES experiment in collaboration with Daresbury

Laboratory, Daresbury, England form July 4-22, 1988.

T. Ferrett, to set up ARPES experiment in collaboration with Daresbury

Laboratory, Daresbury, England form July 4-22, 1988.
SPONSORED SEMINARS AND COLLOQUIA

Division 534, Radiometric Physics

Asmail, Clara, "Static and Dynamic Light Scattering of Dispersive

Systems," Optical Sciences Center, University of Arizona, Tuscon, AZ

,

April 8, 1988.

Poliakoff, Erwin, "Vibrational Gratings and Electron Traps: Fluorescence

Probes of Photoionization," Gaithersburg, MD , April 27, 1988.

Ferret, Dr. T. A., NBS , "Photoelectron Spectroscopy of CO and C02 using

Synchrotron Radiation", Spectral Radiometry Group Seminar, Gaithersburg,

MD , January 11, 1988.

Porter, D., Rochester, NY, "The Usefulness and Limitations of Statistical

Flow Charts", Radiometric Physics Division Seminar, January 29, 1988.

McKoy, Prof. V., California Institute of Technology, Pasadena, CA,

"Studies of Resonant Multiphoton Ionization Processes in Molecules", NBS

Atomic Physics Colloquium, February 8, 1988.

Dils, R. R. , Acufiber, Vancouver, Washington, "Recent Advances in Optical

Fiber Thermometry", Radiometric Physics Division Seminar, March 7, 1988.

Eland, Prof. J. H. D., Physical Chemistry Laboratory, Oxford University,

"Two-Dimensional Mass Spectrometry", Radiometric Physics Division

Seminar, July 15, 1988.

Comer, Prof. J., Department of Physics, Manchester University, "Electron

Spectroscopy Studies of Molecular Resonances", Radiometric Physics

Division Seminar, July 15, 1988.

119

TECHNICAL ACTIVITIES

Division 535, Radiation Source and Instrumentation

CW Racetrack Microtron Project M. Wilson (project leader), R. Ayres, S. Bruce, R. Cutler, E. Lindstrom, P. Liposky, A. Raptakes, and J. Rose

This 185 MeV, 500 /xA cw electron accelerator is shown in Figure 1. It consists of a 5 MeV injector feeding a racetrack microtron (RTM) . In

the microtron, a pair of 180° end magnets are used to recirculate the

electron beam through an 8-m, 12-MeV rf linac up to 15 times for an energy gain of up to 180 MeV. The beam can be extracted from any of 14

separate return lines in 12-MeV steps. In the past year the beam

transport line between the injector and microtron was installed, the two

sections of the 8-m linac were rf-tested at full power, and all beam

transport components on the linac axis and the end magnet vacuum chambers

were installed. All magnets for the return lines were designed, and

procurements have begun. The beam-optical design of the transport line

between the RTM and the free-electron laser (FEL) was completed, and

designs of magnetic components have begun. Initial operation of the

microtron at 17 MeV (one pass through the linac) was successful on September 9, 1988.

The beam transport system from the exit of the injector linac to the

RTM linac axis and along the linac axis through end magnet El is now

complete, including alignment of all bending magnets and quadrupole

focusing magnets, and leak checks of the vacuum envelope. A beam line

for testing the beam after one pass through the 8-m linac has been

installed at the exit of end magnet El. (See Figure 2.) This beam line

includes a high-power beam stop and sufficient beam profile monitors for

beam emittance and energy spread measurements. All beam transport

devices for one pass have been connected to the control system and

tested

.

The two sections of the 8-m MeV linac on the RTM axis have each been

conditioned to a power level between 115 kW and 120 kW. This corresponds

to a voltage gradient exceeding that required for accelerating the

recirculating beam to the nominal full energy of 185 MeV. Further tests

of the rf system were interrupted by two successive failures of the

variable voltage stage of the klystron high voltage power supply,

beginning in early January, 1988. At least one of these failures has

been traced to an accumulation of water in the oil-filled high voltage

tank due to improper sealing of a flange by the manufacturer. The fully

repaired unit was received from the manufacturer in mid-August, 1988, and

rf tests involving full power in all 4 accelerating sections were completed in late August. On September 9, the 5-MeV beam was transported

to the RTM axis, injected into the linac and accelerated. The

121
122
RETURN

-LINE

to

00

03Q-I CDCO

s-o

CDc

03

CL) -Q

CJ

00O

DO

03

>3

S-03

S-o

Q-E

O)

+->

CD

CC

CD sz4-> 4—O

"Oc

CD

00

+-> to

CD

03CD -Q

CXI

CD

S-03

123
Division 535, Technical Activities (cont'd.)

beam was then deflected by end magnet El into the 1-pass beam line

(Figure 2), where the beam energy, energy spread, and emittance was measured

.

Designs have been completed for the steerers, S 19 - S 21 , and for

quadrupoles Q 10 and 1 on the RTM return lines. Drawings of the

quadrupoles have been sent to the NIST shop for fabrication of the steel

parts, and the coils have been ordered. A special, low-remnance nickeliron alloy material has been ordered for the steerers. The electron beam

optics design for the RTM-FEL beam transport line, shown in Figures 1 and

3, is complete. This design includes proper transport of the RTM beam

over all energies between 29 MeV and 185 MeV , and provides for an achromatic beam on the FEL axis. Preliminary designs have been established for the movable deflecting magnet, Dll, and the first two dipole

magnets, D 12H and D 12V . The remaining magnets in the transport line are

(See Figs. 1 and 3): three 2- inch-bore quadrupole doublets (Qi 2 "Qi 7 ) an<^ a dipole bending magnet (D 13 ) in the RTM room; two quadrupole doublets

(Qi 8 -Q2 i) that act as a telescope to form the optimal beam size and waist

position on the FEL axis; an achromatic system of 4 dipoles (D 1A -D 17 ) to

guide the electron beam around the upstream cavity mirror; and a 90°

dipole magnet (D 18 ) to bend the spent electron beam off the laser axis.

Designs of these components are in progress.

Free-Electron Laser Facility R. Johnson (project leader), P. Debenham, C. Johnson, and S. Penner

(contractor)

This is a joint project with the Plasma Theory Branch of the Naval

Research Laboratory (NRL) . The overall goal is to construct and bring

into operation a free-electron laser (FEL) driven by the racetrack

microtron (RTM) electron accelerator at NIST. Good progress was made on many fronts this year. Detailed calculations were done to predict the

FEL performance. Wiggler specifications were written, proposals from

several potential vendors were evaluated, a vendor was selected, a contract was signed, and the vendor has begun construction of the

wiggler. The shielded room that will house the FEL was cleared of other

equipment. Three schemes to increase the RTM peak current were identified and are being investigated; this activity is described in the report

on the High-Current Injector Project. Requirements for the user facility

were identified, and we began clearing the existing experimental area. In the paragraphs to follow we discuss details of the FEL design and

progress during the year.

Our colleagues at NRL have used the self-consistent, threedimensional computer code SHERA (which they developed) to assess the

effects of the transverse emittance of the electron beam on the performance of the FEL. They calculated values of the small-signal power gain,

G

p

, for normalized transverse emittance, e n , between 5 mm-mrad (or nm)

124
200

MeV

Dunp

/

Faraday

Cup

125

Figure

3.

Plan

view

of

the

FEL

wiggler,

electron

beam

transport,

and

optical

cavity.
Division 535, Technical Activities (cont'd.)

and 20 ^m, with the results shown in Figure 4. The design value of e n for the RTM is 5 ^m, and the measured value for the 5 MeV injector beam

is less than 1 /im. The power gain calculated for the design emittance

will readily support lasing over the planned wavelength range.

NRL has developed a Gaussian optical beam formalism for including

mirrors in SHERA to convert it to an oscillator code. This will allow us

to study the evolution of radiation in the optical cavity and evaluate

performance of the FEL in the presence of diffraction and mode mixing.

Meanwhile, we have used published diffraction tables to estimate losses

from the mirrors and intracavity vacuum chamber apertures. These losses

are negligible for UV and visible wavelengths and are small for the IR

wavelengths at which we plan to lase . The losses from diffraction on the

vacuum chambers of the wiggler and the electron beam dump magnet are estimated to be 0.6% and 0.2% per pass, respectively, at 10 ^m. These

losses increase rapidly with wavelength and will prevent lasing at

wavelengths above 12 /xm.

Imperfections in the wiggler magnetic field can degrade FEL performance by causing the electrons to "walk" off the radiation axis and by

altering the path length of the electrons and hence their phase relative

to the radiation field. In order to evaluate these effects, NRL has

developed computer codes to model the propagation of electrons through

wiggler fields with no radiation field and has checked the results for

agreement with analytic expressions. They have also modified computer

code SHERA to include wiggler field errors. A preliminary SHERA calculation was performed for a wiggler with no electron steering correction and

with 0.5% rms random (uncorrelated) field errors. The phase error calculated for this case would degrade performance significantly. The

real wiggler, however, will have electron steering coils and field errors

that are predominantly correlated, both of which will reduce phase errors substantially. NRL is currently incorporating these features into the

formalism and computer codes.

For a saturated FEL in the one - dimens ional , low-gain model with a perfect, untapered, N-period wiggler, the maximum efficiency for extracting power from the electron beam is 1/2N. Using this model, we have

estimated the optical output power of our FEL for commercially available

laser mirrors. The calculated cw output is in the range 50-200 W for 200 nm < A < 7 /xm, and is approximately 20 W for 7 /xm < A < 10 jxm. We are performing more accurate, three-dimensional calculations.

The conceptual design of the optical cavity is complete. We have

chosen a two-mirror, linear cavity with a mirror spacing of 8.062 m. This spacing gives a round trip light travel time of 53.78 ns, which, at

the RTM injector frequency of 74.375 MHz, implies that there will be two

electron pulses and four light pulses in the optical cavity at one time.

Since the RTM is a cw accelerator and there is gain in the laser only

126
o

OsJ ooo

C\J Qd

CsJ 6d

(/) coI

+->

<T3

=3O

cu

=3CD Ll

127

Radiation

Wavelength X

(^.m)

Power

gain

asa

function

of

radiation

wavelength

from

the

3-D

ce

(peak

electron

current

of

2A).
Division 535, Technical Activities (cont'd.)

when an electron bunch is present, the FEL behaves as a cw, harmonicmode- locked laser. The cw nature of the accelerator results in very high

average output power for the FEL.

For cavity mirrors, we plan to use multi-layer dielectric (MLD)

coatings on transparent substrates. An advantage of MLD coatings is the

ability to couple the light out through one mirror by using a partially

transmitting/partially reflecting MLD coating. Compared to metal

mirrors, the spectral bandwidth, or tuning range, is narrow. However, in

the visible and UV , metal mirrors cannot be constructed with the high

power reflection coefficients (up to R = 99.9%) that are necessary

because ours is a low-gain laser. The cavity mirrors must have high

damage thresholds, as we expect the peak irradiance to be 1-2 GW • cm

-

2

, and the average power to be 200-400 kW-cnf 2

. As discussed above, the

losses from diffraction on the cavity mirrors and the intracavity vacuum

chamber apertures will be negligible at ultraviolet and visible wavelengths and small at the infrared wavelengths at which we plan to

operate

.

The minimum wavelength for lasing can be reduced by lasing on the

third harmonic because G

p for the third harmonic exceeds that for the

fundamental. This is done by maintaining a high-Q optical cavity at the

desired wavelength while decreasing the electron beam energy by the

factor 3” 1 /

2

. We may be able to reach 150 nm by this means.

The wiggler will have a peak field of 0.54 T, 130 periods of 2.8 cm

for UV and visible operation, and 65 periods for IR operation. Proposals were received from several potential wiggler contractors in October,

1987, and were evaluated by an internal technical committee, with Dr.

Brian Kincaid (AT&T Bell Laboratories) acting as an outside consultant.

In May, 1988 a contract was signed with Brobeck Division of Maxwell

Laboratories to construct the wiggler. The contractor has completed the

mechanical and magnetic design and has constructed a one-period, fullscale model magnet which fully meets the specifications.

The room where the wiggler and optical cavity will be located has

been cleared of interfering equipment. (The layout in this room is shown

in Figure 3.) We have measured ionizing radiation levels in this area during operation of the NIST neutron time-of-f light facility, when a 5 kW

electron beam from the NIST 110 MeV linac passes through the FEL area. The measured radiation levels are in the range of 10-100 krad per year,

which will give the samarium-cobalt wiggler magnets an estimated useful

lifetime of 5000 years. Lifetimes of optical components at this radiation level will be 1-10 years, longer than lifetimes due to optical

radiation damage. We have also initiated sound and vibration measure- ments in the room in order to determine isolation specifications for the

optical cavity.

128
Division 535, Technical Activities (cont'd.)

As originally planned, the user facility was to consist of two

experimental rooms: an existing room, XAl , adjacent to the FEL and a building addition above ground. XAl was also to house electron beam

lines for high-energy dosimetry and x-ray research. We have recently

reassessed these plans. By relocating the dosimetry and x-ray beam lines

in another existing experimental room, we can make the full area of XAl

(1700 sq ft) available to FEL users at all times. The revised facility

is shown in Figures 5 and 6. We are not planning to construct the aboveground building at this time. XAl was formerly a measurement room for

the NIST 150-MeV Electron Linac ; the equipment associated with that use

is being removed, and plans are complete for conversion to the FEL user facility

.

High-Current RTM Injector Project Roy Cutler (project leader), E. Linds trom, and S. Penner

(contractor)

The present RTM injector consists of a 100 kV, 5 mA dc , thermionic

electron gun followed by a chopper/buncher system and a 5 MeV cw linac.

The injector produces beam pulses at 2380 MHz (the rf drive frequency)

with a maximum of 0.35 pC per pulse. A peak electron beam current of 2-4

A is required in the FEL to achieve lasing. For a 3.5-ps long beam

pulse, this is 7-14 pC per pulse. We have proposed to increase the

charge per pulse without increasing the average current in the RTM

(limited by the rf power available) by reducing the beam pulse frequency

to 74.375 MHz, the 32nd subharmonic of the rf frequency.

The electron beam that drives the FEL must have a longitudinal

emittance of 20 keV- degrees or less and a normalized transverse emittance

of 5 nm or less. Actual beam measurements made at 5 MeV on the existing

injector have exceeded these goals, but achieving them at the required

peak current is more difficult. We are evaluating several methods of

increasing the current beam with 100 keV injection into the present

injector linac. We will retain 100 keV injection primarily for cost

considerations. However, this means we must transport a high-current

beam from the electron gun to the linac with significant space charge.

To calculate space-charge effects, we are using the electron beam

transport code PARMELA as an aid to designing the 100 keV transport line.

Two basic technologies have been studied for achieving this higher

current beam for the FEL. The first involves the use of a laserilluminated photocathode. The time structure of the drive laser is

designed to produce the time structure desired for the emitted photoelectrons, pulses as short as 30 ps . Pulse - to-pulse amplitude and pulse

shape stability of the drive laser are important issues that need to be

addressed. Existing, several-watt cw, mode-locked drive lasers require

cathode materials with quantum efficiencies of approximately 1% to

achieve the required peak current. Materials such as CsSb have the

129
130

Figure

5,

Plan

view

of

the

FEL

Facility.
False Floor

Figure 6. Plan view of user's experimental area,

optical tables.

Areas 1-5 indicate

131
Division 535, Technical Activities (cont'd.)

necessary quantum efficiency but have too short a lifetime due to

contamination in a good accelerator vacuum (10‘ 9 Torr) to be acceptable

for user facility operation. We are collaborating with the AT-7 Group at

Los Alamos to develop a suitable photocathode.

The second technology that we are studying is conventional rf

chopping and bunching, as in the existing 100 keV RTM injector. In this

method, a thermionic electron gun is pulsed at 74.375 MHz, with a pulse

length of approximately 2.5 ns, the limit for electron guns at this

repetition rate. This pulse is then shortened by sweeping the electron

beam over an aperture with rf deflection cavities or deflection plates.

The beam is then compressed to 15 ps for injection into the injector

linac using one or two bunching cavities. We are simulating three

possible 100 keV injection lines with PARMELA, each using a different

method of chopping and bunching. The first design uses a 100-200 mA gun

current and chops to either 70 or 140 ps-long pulses. These pulses would

then be compressed by the existing buncher to 15 ps . The second design

uses a 40 mA gun current chopped to 280 ps and bunched by a 1190 MHz

cavity and by the existing buncher. The third design uses a 20 mA

electron gun, chopped to 600 ps and bunched by a 297.5 MHz rf cavity and

by the existing buncher. The best design will be chosen on the basis of

feasibility, cost, and beam quality.

Accelerator Operations J. Broberg (project leader), W. Dobbie,

T. Hotchkiss, A. Lopez, and J. Pitt

The Division operates and maintains two major electron accelerators

in support of Center programs: the Linac and the Racetrack Microtron

(RTM) . Since each accelerator requires the total installed power and

cooling water capacity of approximately 1 MW, they are not operated

simultaneously. This year the Linac was operated exclusively to produce

neutrons in the time-of-flight facility (TOFF) for neutron cross-section

standards measurements and radiography. We supplied 1148 hours of actual

Linac beam to TOFF with 30 hours of unscheduled maintenance, for an operational efficiency of 97%.

The operations staff assists in the construction of the RTM and is

being trained in RTM operations. This year we assisted in rf- testing the

RTM 8-m linac and in one-pass beam tests. We are also responsible for

maintaining the RTM and enhancing its reliability as a component of a user facility. Twice this year the variable- transformer stage of the 1-

MW klystron power supply failed and was returned to the manufacturer for

repairs. At least one and possibly both failures were caused by the use

of an undersized gasket at manufacture. As a precaution, we are planning

to procure a replacement unit to avoid the problematic sliding contact in

oil that is currently used. We have also constructed and installed a new interlock circuit to prevent collisions of wirescanners and viewscreens

132
Division 535, Technical Activities (cont'd.)

and have modified the modular, 30-watt magnet power supplies for improved

reliability

.

Mechanical Instrumentation D. Mohr (project leader), R. Baker, J.

Billos, C. Bostian, J. Bradley, D. Fox, H.

Lantz , and W. Rymes

Mechanical instrumentation services were provided for the Center in

connection with its particle accelerators and experimental programs. The

service provided consisted of design, construction, and installation of new equipment and facilities as well as maintenance and modification of

existing equipment to improve performance and reliability.

Some examples of devices designed and constructed this year are:

the support mechanism for the RTM end magnet vacuum boxes to allow magnet

linear motion while holding boxes in position and maintaining vacuum

system integrity; the vacuum system for one-pass RTM operation; RTM

return path quadrupoles; and a thin window vacuum/pressure photodetector

to be used on the Linac

.

It is desirable to use aluminum rather than stainless steel vacuum

chambers in RTM magnets to avoid distorting the very precise magnetic

fields. We have developed a method of welding a rectangular aluminum

tube into an aluminum flange with minimal distortion. This allows us to

construct aluminum vacuum chambers with the new, hardened aluminum

conflat flanges for high vacuum.

Some examples of major installation and maintenance tasks for this

year are: installation and alignment of all dipole and quadrupole

magnets and associated vacuum hardware for one-pass RTM operation; repair

of a large vacuum chamber on the Linac; rebuilding of Model 12 electron

guns for our Linac and for NRL; and rebuilding of vac- ion pumps for the

Linac, SURF and other divisions in CRR.

We now have three operational CAD/CAM work stations. These are essential for designing RTM and FEL components in a timely manner. The

group staff has been heavily involved in the planning of the FEL program,

and the group leader served as the contracting officer's technical

representative for the wiggler.

Electronics Instrumentation J. Whittaker (project leader), A.

Marella, J. Owen, L. Shuman, N. Wilkin,

and D. Tirosh (guest scientist)

The Division provides consultation, design, construction and

maintenance services to CRR staff requiring electronics instrumentation,

data acquisition systems and computer systems. With a relatively small

staff, we rely heavily on computer-aided design techniques for printed

133
Division 535, Technical Activities (cont'd.)

circuit board production. This year 85 instruments have been constructed

and 109 repaired and modified. Repair services are limited to equipment

constructed in-house and special items that cannot be repaired commercially.

We designed measurement instruments for pulse radiolysis experiments. Control and data acquisition systems were completed for X-ray

standards measurements and high dose dosimetry. Further instrumentation

has been provided for the States Regional Calibration Centers as the

program expands. Instrumentation provided for the RTM includes control

circuits, wire-scanner amplifiers and preliminary examination of possible

power supply designs for the small magnet power requirements. A con- siderable amount of software has been written for GPIB instrument

control. We also provided experimental equipment for the Harry Diamond

Laboratories fuze instrumentation program.

We have provided consulting services to CRR, other centers, DOC, DOE

and HDL. We have installed 30 small 386-based computers together with

extensive software support for CRR and Harry Diamond Laboratories. Our

Hewlett-Packard 350 computer, which is normally used for electronic CAD, was also used for the detailed mechanical design of a large detector

array by a CRR physicist. Software to permit much faster and more

automated printed circuit board design is being examined.

Radiation Instrumentation Standards L. Costrell

The Division provides national leadership in the standardization of

nuclear instrumentation. The standards work falls into three categories:

National Voluntary Standards, Nuclear Instrumentation Module (NIM)

Committee Standards, and International Electrotechnical Commission (IEC)

Standards

The Division plays an active role in the development and processing

of National Voluntary 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.

The NIM committee oversees development and maintenance of instrument

standards, in cooperation with the National Laboratories, primarily for use in nuclear applications. NIST has the management responsibility for

this work, with L. Costrell serving as Chairman of the NIM Committee.

134
Division 535, Technical Activities (cont'd.)

The NIM system1,2 has been adopted nearly universally in the U.S. and a continuous coordination effort is required, involving contact with

numerous laboratories and manufacturers. Similar management, direction

and maintenance services are provided in the U.S. with regard to the

international CAMAC (Computer Automated Measurement and Control) system

3

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 responsibility is the FASTBUS

high speed modular data acquisition system for high energy physics and

other applications. 4,5 The FASTBUS development has been a major effort

with commercial equipment now available and systems in operation or in

preparation in numerous laboratories in the U.S., Europe, and Japan. The

preparation of reports for the above systems involves a number of

individuals and laboratories. Coordination and processing, as well as writing of some sections, is handled by the National Institute for

Standards and Technology. The documents are usually issued as Reports of

the Department of Energy and then processed as Standards of ANSI, 6 and

IEC

.

7

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 consul1 "Standard Nuclear Instrument Modules," AEC (now DOE) Report TID20893 (Rev 4) , July 1974 (currently under revision)

.

2 "Standard NIM Digital Bus (NIM/GPIB) , " Department of Energy

Report DOE/ER-0173, 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,"

Report D0E/ER-0189, December 1983.

5 "FASTBUS Standard Routines," Department of Energy Report DOE/ER0325, March 1987.

6 "FASTBUS Modular High Speed Data Acquisition and Control System,"

ANSI/IEEE Std 960-1986.

7 "FASTBUS Modular High Speed Data Acquisition System,"

International Electrotechnical Commission Publication 935 (to be

published)

.

135
Division 535, Technical Activities (cont'd.)

tants

8 The study report states that the 1.9 billion dollars is con- sidered to be a minimum figure conservatively arrived at on the basis of

available data. 1.7 billion dollars is attributed to the NIM system

initiated by the Center for Radiation Research9 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 measurable data were available." The total worldwide savings can be reasonably projected to be

double the U.S. savings.

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 Interchangeability

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, CAMAC and FASTBUS standards. 1,2,3 ’ 6 Similarly, the international standards for semiconductor detectors for charged particles, for

amplifiers and preamplifiers used for radiation detection, and several

other standards are technically identical to ANSI/IEEE standards developed by the committees referred to above.

8 "Benefit Analysis of Selected Accomplishments of DOE'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.)

9 "Standard Modules for Nuclear Instrumentation," NBS Report 8137,

December 5, 1963, L. Costrell.

136
INVITED TALKS

Division 535, Radiation Source and Instrumentation

Debenham, P.H., "The NBS Free-Electron Laser Facility," George Washington

University, Washington DC, February 12, 1988.

Debenham, P.H., "Research Opportunities Below 300 nm at the NBS FreeElectron Laser Facility," Topical Meeting on Free-Electron Laser

Applications in the Ultraviolet, Cloudcroft, NM, March 2-5, 1988.

Johnson, B.C., "The NBS Free-Electron Laser Facility," Fourth

International Symposium on Resonance Ionization Spectroscopy and Its

Applications, Gaithersburg, MD , April 14, 1988.

Johnson, B.C., "The NBS Free-Electron Laser Facility," 19th Annual

Meeting of the Division of Atomic, Molecular, and Optical Physics of the

American Physical Society, Baltimore, MD , April 18, 1988.

Johnson, B.C., "The NBS-NRL Free Electron Laser Program," 3rd Annual

Medical Free-Electron Laser Contractor's Meeting, Univ. of Utah, Salt

Lake City, UT, May 16 - 18, 1988.

Penner, S., "NBS Free Electron Laser Facility, University of Maryland,

College Park, MD , October 23, 1987.

Penner, S., "NBS Free Electron Laser Facility," JILA, Boulder, CO,

February 10, 1988.

Wilson, M.A.

,

"Electron Beam Performance Expectations from the NBS-LANL

Racetrack Microtron," Naval Surface Weapons Center, White Oak, Silver

Spring, MD, March 30, 1988.

137
PUBLICATIONS

Division 535, Radiation Source and Instrumentation

Debenham, P.H., Bruce, S.S., Penner, S., and Wilson, M.A., "The Injection

Chicane of the NBS-Los Alamos Racetrack Microtron," Proc . of 1987 IEEE

Particle Accelerator Conference, 1452, Dec. 1987.

Debenham, P.H. and Johnson, B.C., "Research Opportunities Below 300 nm at

the NBS Free Electron Laser Facility," Optical Society of America

Technical Digest Series 4 76, March 1988.

Cutler, R.I., Owen, J., and Whittaker J., "Performance of Wire Scanner

Beam Profile Monitors to Determine the Emittance and Position of High

Power CW Electron Beams of the NBS-Los Alamos Racetrack Microtron", Proc.

of 1987 IEEE Particle Accelerator Conference, 625, Dec. 1987.

Cutler, R.I. and Young, L. , "Performance of the High Power RF System of

the NBS-Los Alamos Racetrack Microtron," Proc. of 1987 IEEE Particle

Accelerator Conference, 1863, Dec. 1987.

Johnson, B.C., Debenham, P.H., Penner, S., Tang, C.-M., and Sprangle , P.,

"The NBS Free Electron Laser Facility," Bull. Am. Phys . Soc

33^ 916,

April 1988.

Johnson, B.C., Wang, M.-X., and Weiner, J., "Crossed-beam Studies of

Associative Ionisation in Heteronuclear Systems: NaLi+ Production from

Li* + Na and Na* + Li Collisions," J. Phys. B: At. Mol. Opt. Phys. 2_1 (1988) 2599.

Penner, S., "RF Linac Based Free Electron Lasers," Proc. of 1987 IEEE

Particle Accelerator Conference, 183, Dec. 1987.

Maruyama, X.K., Penner, S., Tang, C.-M., and Sprangle, "Proposal for a Free Electron Laser Driven by the National Bureau of Standards' CW

Microtron," Nuclear Instruments and Methods in Physics Research A259

(1987) 259-262, North-Holland , Amsterdam.

Tang, C.-M., Sprangle, P., Penner, S., and Maruyama, X.K., "Analysis of

Free Electron Laser Performance Utilizing the National Bureau of

Standards' CW Microtron," Proc. of 1987 IEEE Particle Accelerator

Conference, Dec. 1987.

Wen, J., Lucatorto, T., Johnson, B.C., and Clark, C., "Two-Photon

Transitions in Beryllium," Phys. Rev. A 37 4207, June 1988.

138
Division 535, Publications (cont'd.)

Wilson, M.A. , Ayres, R.L., Cutler, R.I., Debenham, P.H., Lindstrom, E.R.

Mohr, D.L., Penner, S., Rose, J., Young, L.M. , and Stovall, J.,

"Performance of the 5 MeV Injector for the NBS-Los Alamos Racetrack

Microtron," Proc . of 1987 IEEE Particle Accelerator Conference, 322, Dec

1987.

Wilson, M.A., Debenham, P.H., Penner, S., and Bruce, S.S., "Orbit

Reversing Magnets for the NBS-Los Alamos Racetrack Microtron," Proc. of

1987 IEEE Particle Accelerator Conference, 1469, Dec. 1987.

139
PUBLICATIONS IN PREPARATION

Division 535, Radiation Source and Instrumentation

Debenham, P.H., Bruce, S.S., Penner, S., and Wilson, M.A.D., "The

Injection Chicane of the NBS-Los Alamos Racetrack Microtron," to be

published in IEEE Transactions on Nuclear Science.

Penner, S., Ayres, R. , Cutler, R. , Debenham, P., Johnson, B.C.,

Lindstrom, E., Mohr, D., Rose, J., Wilson, M. , Sprangle , P., and Tang,

C.M., "The NBS/NRL Free Electron Laser Facility," to be published in

Nuclear Instruments and Methods in Physics Research.

Tang, C.-M., Sprangle, P., Penner, S., and Maruyama, X.K., "Analysis of

Free Electron Laser Performance Utilizing the National Bureau of

Standards' CW Microtron," to be published in J . of Applied Physics.

Tirosh, D. and Whittaker, J., "A Fast Pulse Amplifier for Pulse

Radiolysis Measurements with Digitally Controlled DC Offset," to be

published in Nuclear Instruments and Methods.

Wilson, M.A., Debenham, P.H., Penner, S., and Bruce, S.S., "Orbit

Reversing Magnets for the NBS-Los Alamos Racetrack Microtron," to be

published in IEEE Transactions on Nuclear Science.

140
TECHNICAL AND PROFESSIONAL COMMITTEE PARTICIPATION AND LEADERSHIP

Division 535, Radiation Source and Instrumentation

John B. Broberg

Member, Program Committee of the 1988 Linear Accelerator

Conference

Louis Costrell

Chairman, NIM (National Instrumentation Methods) Committee

Chairman, American National Standards Institute Committee N42

,

Radiation Instrumentation

Member, American National Standards Institute Nuclear Standards

Board

Member, American National Standards Institute Nuclear Standards

Board Planning Committee

Secretary, IEEE Nuclear Instrumentation and Detectors Committee

Ex-Officio Member, IEEE Nuclear and Plasma Sciences Society

Administrative Committee

Chairman, IEEE Nuclear and Plasma Sciences Nominating Committee

Chairman, IEEE Nuclear and Plasma Sciences Annual Meetings Committee

Member, Organizing Committee, 1989 IEEE Particle Accelerator

Conference

Member, IEEE Nuclear Science Symposium Program Committee

Member, U.S. National Committee of the International

Electrotechnical Commission (IEC)

Technical Advisor, U.S. National Committee of the International

Electrotechnical Commission (IEC)

Chief U.S. Delegate, International Electrotechnical Commission

Committee TC45 , Nuclear Instrumentation

Chairman, International Electrotechnical Commission Committee TC45

Working Group 9, Detectors

141
Division 535, Technical and Professional Committee Participation and

Leadership (cont'd.)

Philip Debenham

Technical Consultant, DOE Review Committee, CEBAF Semi-Annual

Review, Nov. 17-19, 1987.

Reviewed spectrometer design and project management, DOE Technical

Advisory Panel on CEBAF High Resolution Spectrometers

Member, Program Committee, 1989 IEEE Particle Accelerator Conference

Eric Lindstrom

Editor, Proceedings of 1987 IEEE Particle Accelerator Conference

Samuel Penner

Member, Organizing Committee, 1989 IEEE Particle Accelerator

Conference

Julian Whittaker

Member, ASTM Committee D22 on Sampling and Analysis of Atmospheres

Secretary, Department of Commerce, Bureau of Export Administration,

Electronic Instrumentation Technical Advisory Committee

Mark Wilson

Member, Program Committee, 1989 IEEE Particle Accelerator Conference

Member, Review committee, Advanced Test Accelerator, Lawrence

Livermore National Laboratory, Livermore, CA

142
MAJOR CONSULTING AND ADVISORY SERVICES

Division 535, Radiation Source and Instrumentation

1. S. Penner and M. Wilson continue to provide Accelerator Technology

and Assessment and Oversight for DARPA.

2. S. Penner serves as a consultant to the U.S. Army Strategic Defense

Command on particle accelerator issues related to programs in Free

Electron Lasers and Neutral Particle Beam Weapons.

3. N. Wilkin serves as consultant on microcomputers and semiconductor

radiation hardness testing to Harry Diamond Laboratories.

4. N. Wilkin serves as consultant on microcomputer control of fuze

instrumentation for Harry Diamond Laboratories.

143
SPONSORED SEMINARS AND COLLOQUIA

Division 535, Radiation Source and Instrumentation

Thomas M. Baer, Spectra-Physics , Inc., Mountain View California,

"Subpicosecond Optical Pulse Generation Using Compression Techniques,"

October 22, 1987.

Spilios Riyopoulos , Science Applications International Corporation,

McLean, Virginia, "Reflection Matrix for Gaussian Light Beams in FEL

Oscillators," December 3, 1987.

144
TECHNICAL ACTIVITIES

Division 536, Ionizing Radiation

The functions of the Ionizing Radiation Division are summarized in

the following table:

• 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 theoretical and experimental research on the fundamental

physical and chemical interactions of ionizing radiation with matter

to provide the competence for:

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 transformations 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 and 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 well-characterized sources of electrons,

photons, and neutrons to provide:

145
Division 536, Technical Activities (cont'd.)

Primary radiation standards and fields

Well-characterized beams of radiation for research on radiation

interactions and for measurement methods development.

The division was restructured in March 1988 to a simpler organizational

structure

Ionizing Radiation Division (R. S. Caswell, F. J. Schima)

Office of Radiation Measurement (E. H. Eisenhower)

Radiation Interactions and Dosimetry (B. M. Coursey)

Neutron Interactions and Dosimetry ( J . A. Grundl)

Radioactivity (D. D. Hoppes)

Some of the goals in restructuring were: better balance between fundamental research and services, better support for fewer activities, fresh

leadership, choice of state-of-the-art research activities, effect econo- mies where possible by combining support services, and to improve other

objects levels. Due to an FY 88 funding shortage a staff reduction also

took place at the time of the reorganization.

Some of the key future programs of the Ionizing Radiation Division are:

Radiation Interactions Research

Chemical mechanisms of biological effects and applications to radiation dosimetry

Physics of radiation interactions with condensed matter (at the

microscopic level, especially)

Neutron and high-LET radiation interactions (includes radon)

Dissemination of Measurement Services

Develop national measurement support system for ionizing radiation

Radiation Measurement Science

High-energy electron & photon dosimetry standards (5-35 MeV)

Chemical dosimetry/industrial radiation processing

Dosimetry for radiation protection monitoring

146
Division 536, Technical Activities (cont'd.)

Radon measurement standards

Radionuclide atom counting

Radiology imaging research

I . 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

through a national system of secondary standards laboratories. 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 Commission,

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 these organizations to satisfy specific measurement quality assurance requirements

.

Radon (R. Colie & J. M. R. Hutchinson)

The Office continued to provide a leadership role and collaborate

with members of the Radioactivity group on several projects: upgrading

and replacing the primary radon measurement system; continuing the

development of the prototype transfer standard for flux density measurements;

completing the development and cross calibrations for the new Nal(Tl)

secondary measurement system; participating in measurement intercomparisons

with the principal U.S. radon measurement laboratories, and planning for

a new intercomparison with international metrology laboratories; assembly

of a second radon- in water standard generator; and initiating a new

project for a primary radon calibration which is independent of a 226 Ra

standard

.

In the past year, significant progress has been made on replacing

the old primary radon measurement system which serves as the national

standard for radon measurements. The four new pulse ionization chambers,

custom-built to our specifications by Reuter-Stokes , were delivered and

preliminary performance evaluations were completed. All of the ancillary

electronics for power, signal processing, and computer control have been

assembled. Testing of the electronic counting systems is ongoing.

147
Division 536, Technical Activities (cont'd.)

Construction of the extensive gas handling and purification manifold was initiated this Spring. It is anticipated that initial testing and calibrations of the completed system will begin in the next six to nine

months

The project to develop a large surface area flux density standard is

continuing. A 40-cm diameter prototype has been operational for the past

two years. Preliminary calibrations for both the constrained and uncon- strained flux density were completed, and were shown to be in agreement

with theoretical calculations based on a diffusion model for the standard.

These initial successes, however, were offset by a major setback in this

development work. Unexpected large evaporation losses by transpiration

of water through the polyethylene membrane over the past 26 months resulted

in the formation of air gaps at the water-polyethylene interface as well

as changes in the initial radium solution concentration. The former

result introduces an undesirable permeation component in the operation of

the otherwise purely diffusive transport of radon in the standard. The

latter changes the radon production rate in the standard. As a result,

the prototype had to refilled to make up the evaporation losses. Work is

ongoing to establish operating procedures that will either minimize the

evaporation losses or simplify the make-up refilling. The final series

of calibrations against the primary measurement system was recently

initiated in collaboration with a guest worker.

A measurement intercomparison with the five principal laboratories

within the U.S. that maintain an independent radon calibration capability

was completed in the past year. An unsatisfactorily large, systematic

measurement discrepancy of over 7 percent among these laboratories was found despite the fact that all of the laboratories' calibrations were based on similar NIST 226 Ra solution standards. We are continuing to

work with these laboratories to try to understand and resolve the discrepancy. A new international radon measurement intercomparison among

the national metrology laboratories (e.g., PTB and NPL) is also being

planned for early 1989.

Work also has been started on an initiative to perform a primary

radon calibration which is not based on an indirect or comparative mea- surement against a 226 Ra standard. This primary calibration, expected to

have an overall uncertainty of 1 to 2 percent, will be based on liquid

scintillation counting techniques using radium-free radon solutions. A

radon- in-water standard generator which was successfully developed several

years ago will be used to prepare the solutions. A second generator is

presently being assembled for this work (the first prototype generator

was delivered to EPA) . This primary calibration, if successful, will be a significant achievement in providing the first independent confirmation

of the radium calibrations used over the past 50 years.

148
Division 536, Technical Activities (cont'd.)

Measurement Uncertainties (R. Colie)

An international guidance document for the treatment and reporting

of measurement uncertainties has been under development for the past 18

months under the chairmanship of a member of the Office. The document is

being developed by a joint international working group representing the

International Organization for Standards, the International Electrotechnical

Commission, the International Bureau of Weights and Measures, and the

International Organization of Legal Metrology. The first draft completed

last year required substantial changes in content and nearly a complete

rewrite. The second draft was completed in September, and presently is

being distributed and made available to a wider audience for comment.

The U.S. industrial metrology community, which has considerable interest

in the topic, has been kept well apprised of the ongoing efforts through

an ad hoc advisory group of over 70 members.

Instrument Calibration Computer Code (H. T. Heaton)

The computer code used to assist the state-sector labs in their

instrument calibrations and routine in-house QC programs is being used by

the labs in CA, IL, and SC. This code is written in a compiled BASIC

with the source code for the menu- driven programs occupying over 800k on

the fixed disk. This code includes two instrument-specific calibration

procedures, as well as a generic calibration procedure, for the types of

instruments most commonly calibrated at state laboratories. For Radcal

instruments, there is a procedure for electrically checking the response

of the instrument including its linearity. There are options for both x- ray and gamma-ray calibrations. The code also includes quality control

procedures for 14 different pieces of the calibration equipment used, and

is necessary to demonstrate that the equipment is performing statistically

in the same manner as it was during the performance test. There are 15

programs for general data analysis and procedures for making measurements

necessary for characterizing the laboratory including a procedure for

determining x-ray beam half -value- layer , with the statistical uncertainty

associated with the linear regression techniques used in this analysis.

There is a program for a nonlinear regression analysis to fit measured

exposure rate as a function of distance from a gamma source to a model

which includes build-up and attenuation in air and gamma rays scattered

from a rear wall. There is also a procedure for electrically calibrating

a modified picoampere source and electrometer. In addition to these

programs for the state-sector secondary labs, many of which are also

necessary for making similar measurement in the Office lab, there are programs for monitoring the equipment and transfer standards used by the

Office for performance tests of the secondary- level labs.

149
Division 536, Technical Activities (cont'd.)

Directory of Calibration Laboratories (H. T. Heaton & E. H. Eisenhower)

One of the national needs in ionizing radiation is for a directory

listing those companies providing survey instrument calibration services.

Thus, the Office, in cooperation with the Radiation Measurements Committee

of the Conference of Radiation Control Program Directors, has revised and

published the "Directory of Commercial Calibration Services for Ionizing

Radiation Survey Instruments". This directory provides detailed information

on companies offering alpha, beta, gamma-ray, neutron, and x-ray calibrations

together with information on the radiation fields available. The directory

was mailed to all of the companies listed and has been sent to all of the

state radiation program directors to assist them in answering inquires as

to where calibration with a particular radionuclide or exposure rate can

be obtained.

Environmental Dosimetry (H. T. Heaton & C. G. Soares)

Environmental dosimeters were irradiated using the NIST cesium and

cobalt beams in a joint program with the Environmental Measurements

Laboratory (EML) to confirm previously observed differences between

participants who use Cs or Co to calibrate their dosimeter readout equipment.

The dosimeters have been read out by the participants, the results reported

back to EML, and preliminary data analysis made by EML. The previously

observed effect is still observable and discussions are under way looking

for common elements among the participants showing the strongest effect.

State-Operated Calibration Laboratories (H. T. Heaton & E. H. Eisenhower)

The Office is continuing to provide technical assistance to five

state sector secondary calibration laboratories (IL, SC, CA, WA, and AR)

These labs provide calibrations of instruments used for diagnostic x-ray

compliance measurements and for x-ray and gamma-ray radiation protection

measurements . Three of these labs were given training in the use of the

computer code (see above) for the calibrations performed at their labs

and the labs are revising their protocols for routine use of this code.

The lab in IL is planning to move to a new facility and they will replace

their existing Cs sources with a 40-Ci and 130-mCi dual unit. They are purchasing an additional 10-Ci Cs source for calibrating pocket dosimeters.

The x-ray capability will remain the same and they are planning to install

a neutron source to be used for constancy checks. They are calibrating

instruments for 9 other state radiation control programs. The lab in SC was accredited by the Conference of Radiation Control Program Directors

(CRCPD) for x-ray calibrations and they are investigating various options

for installing the Cs sources. The lab in WA is only offering gamma-ray

calibrations. All three of these labs successfully passed their annual

performance test required for accreditation by the CRCPD. The lab in CA

has completed the minimum set of measurements necessary to characterize

the lab equipment for both x-ray and gamma-ray calibrations. As soon as

150
Division 536, Technical Activities (cont'd.)

their protocol is satisfactory, they will be given the performance test

necessary for CRCPD accreditation. The lab in AR has recently acquired

several Cs sources and is in the process of installing them. As a result

of a performance test at the high-flux neutron facility, an improved

model of room return was developed to better account for the large neutron

scatter component at that site.

Transfer Standard QC Test Facilities (H. T. Heaton & C. G. Jones)

Two facilities are being developed to monitor the response to radiation

of the transfer standards used in performance tests of secondary laboratories. The first incorporates a 3-Ci Cs gamma-ray source and track

system to reposition the transfer standard in a precise manner. This

system, set up in the Office lab, is presently being used to monitor

transfer standards used in gamma-ray performance tests. The second

facility is being set up in the Radiation Interactions and Dosimetry

Group's industrial x-ray facility and makes use of their 150 kV x-ray

unit and an optical bench for instrument positioning. The mounting

support system for the x-ray tube is being designed and manufactured, as

is the instrument support system.

Private - Sector Calibration Laboratories (E. H. Eisenhower, H. T. Heaton,

& C. G. Jones)

The Health Physics Society has begun to accept applications for

accreditation of secondary laboratories. The first company to apply

(Eberline Instrument Corp.) has been accredited after submitting a satisfactory protocol, an on-site visit, and a successful performance test of

calibrating an instrument in their Cs beam. This performance test involved

several new features. First, the instrument was calibrated by the Radiation

Interactions and Dosimetry Group in the "integrate" mode at a single

exposure rate from their Cs source. The performance test was done using

the instrument in the "rate" mode and at different exposures than it was calibrated. Thus the Office had to develop procedures to determine the

additional uncertainty component of using the transfer standard in different

conditions than it was initially calibrated. Part of this involved

developing in-house quality control procedures to monitor the response of

the transfer standard.

Federally-Owned Calibration Laboratories (E. H. Eisenhower)

Significant progress has been made to develop a program that will

lead to formal recognition of the competence of federally-owned calibration

laboratories. Performance criteria have been prepared for a broad range

of calibrations (i.e., survey instruments, x-ray diagnostic instruments,

dosimeter irradiations, reference-class instruments, and source calibrations). These criteria apply to secondary laboratories, but will be

expanded to include tertiary laboratories in the future. It has been

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Division 536, Technical Activities (cont'd.)

decided that accreditation will be provided under the National Voluntary

Laboratory Accreditation Program (NVLAP) . The Office is coordinating

program development, leading the preparation of criteria, will conduct

proficiency tests, and will participate in on-site evaluation of candidate

secondary laboratories. Departments and agencies actively involved are

DoE, DoD , FDA, and FEMA, represented by a total of 22 individuals from 19

laboratories

II . Radiation Interactions & Dosimetry Group

In the March 1988 reorganization of programs in the Ionizing Radiation

Division, the Radiation Interactions and Dosimetry Group was created

which incorporated most of the personnel and programs of the following

four groups: Radiation Theory, X-Ray Physics, Dosimetry, and Radiation

Chemistry and Chemical Dosimetry. The structure of the new group is

still evolving; it presently comprises four projects:

• Radiation Sources

• Physical Interactions and Dosimetry

• Chemical Interactions and Dosimetry

• Radiation Measurement Services

The Radiation Sources Project consolidates the operation, maintenance,

and updating of the electron, x-ray, and neutron producing sources of the

division in a single project. This change encompasses the 300-kV industrial

x-ray source, the 500- , 1500- , and 4000-keV electron accelerators and the

3000-keV positive ion accelerator. Operationally, this arrangement will

facilitate the servicing and improvements of these sources since more personnel will be available for any particular situations that arise.

The sources are available for the physics and chemistry research programs

of the Division, as well as to other NIST investigators and to the public.

The Physical Interactions and Dosimetry Project combines the experimental,

theoretical and computational research and metrology which was formerly

carried out in three separate Groups. Some of the programs for this

project are in medical therapy, computational dosimetry, radiological

imaging, and personnel protection. Thrusts for the 1990's include:

calculation and measurement techniques for ionizing radiation effects on electronics and interfaces of dissimilar materials; dosimetry for medical

therapy using high-energy electrons and photons from accelerators; development of real-time inorganic dosimeters for medical and industrial

applications; and computation, design and measurement techniques for

optimizing radiographic image quality with minimum dose through digital

imaging

152
Division 536, Technical Activities (cont'd.)

The Chemical Interactions and Dosimetry Project has three main elements:

radiation chemistry, chemical dosimetry, and post irradiation dosimetry

(PID) . The aim for these programs is understanding the basic mechanisms

of radiation interactions in organic systems and applying this information

to problems in the health sciences, industrial applications, and hardness

testing of components, as well as personnel radiation protection. The

thrusts for the 1990' s include: respond to increasing needs of emerging

technologies for ionizing radiation measurements in processing and electronics; use electron paramagnetic resonance (EPR) techniques to elucidate

free radical processes in irradiated materials; study energy deposition

and effects in model systems using GC-MS, HPLC , electrochemical and

radioanalytical techniques; develop real-time chemical dosimeters for

industrial, medical and research applications.

The Radiation Measurement Services Project combines the calibration

services and measurement assurance programs formerly carried out in the

X-Ray Physics and Dosimetry Groups. These calibration services include

three of the most used services in NML: x- and 7 - instrument calibrations,

ferrous sulfate dosimetry for medical therapy, and high radiation dose

calibration services. The project also includes technical support for

the secondary standard dosimetry laboratories (SSDLs) as well as measurement

assurance programs in dosimetry and radiographic imaging for other agencies.

The thrusts for the 1990 's will be to automate and update existing services,

to develop new services for emerging industries, and to assist in implementing new measurement assurance programs and secondary laboratory

programs which will increase our leverage on ionizing radiation measurements

of x- and 7 -rays and electrons.

The technical activities of these four projects during the past year are given on the following pages.

A. Radiation Sources (C. E. Dick)

In the past year significant improvements have been made to several

of the sources operated in this Project as outlined below.

The experimental room associated with the 300-kV x-ray machine has

been improved with the addition of optical benches and a mount for the

tube head on these benches. This system will permit accurate repositioning

of the source to object and source to detector distances in those measurements where reproducibility of these distances is essential. This machine

has been utilized for a number of measurements including the radiography

of sections of the oil tank which collapsed in Pittsburgh and in the

determination of the resolution and sensitivity of a new class of x-ray

imager, the Dynamic Random Access Memory (DRAM) imaging system.

Modifications to the 4-MeV electron Van de Graaff have continued

with the addition of a non- dispers ive bending magnet system for the

153
Division 536, Technical Activities (cont'd.)

electron beam. This system will facilitate the positioning and reproducibility of the electron beam at either end of the horizontal flight tube.

In addition, the design of this system allows additional experimental

space for the zero degree high current experimental location. At present,

this accelerator is being utilized for the generation of standard electron

fields for instrument calibration and for experiments in pulsed radiolysis.

Work has been initiated on the 3 MeV positive ion accelerator which

is used to produce neutrons via nuclear interactions. Modifications to

the electronics have been initiated and the accelerator is now capable of

high voltages up to 3 million volts. Currently, modifications have been

undertaken to improve the vacuum in the accelerator tube structure to

increase the available beam current, particularly for deuteron beams. In

the past year, experiments have been carried out to provide standard

fields of 6-7 MeV photon beams for experiments in dosimetry and calibration

services

B . Physical Interactions and Dosimetry Project

Calculational Dosimetry (M. J. Berger & S. M. Seltzer)

A microdosimetry calculation has been completed and published (Phys.

Med. Biol. 3_3, 583 (1988)) pertaining to the distribution of energy

deposition events in smaller spherical sites in water (with diameters of

1 micron or smaller in unit density material) . The method takes into

account energy- loss straggling and the transport of energy by secondary

electrons, and goes respect beyond the classical calculations of Caswell

and Coyne based on the continuous-slowing down approximation. Results

have been obtained for monoenergetic protons between 1 to 20 MeV and for

proton beams released in the interactions of 14-MeV and 20-MeV neutrons

with hydrogen nuclei.

A Monte Carlo calculation has been completed of the spatial pattern

of absorbed dose, and of the spectra of secondary photons and electrons,

around cladded 60 Co gamma-ray sources used in industrial applications.

Transport Theory (M. J. Berger & S. M. Seltzer)

The NIST general purpose Monte Carlo electron-photon transport

program ETRAN has been thoroughly reviewed in six chapters of a book to

be published in 1988 or 1989. These chapters cover the input cross

sections, the characteristics and limitations of the Monte Carlo model,

computational aspects, and various applications. Stimulated by this

review, the ETRAN code has been thoroughly revised, including improved

cross sections and sampling techniques, and refinements of the Monte

Carlo model. As the result of this updating, the code is now easily

portable to any computer with a FORTRAN 77 compiler installed, and has

been ported to a work station microcomputer. The throughput achieved on

154
Division 536, Technical Activities (cortt'd.)

this microcomputer is comparable to that obtained on a mainframe, but at

much lower cost.

Cross Sections: Photons (M. J. Berger, S. M. Seltzer, & J. H. Hubbell)

A photon cross section data base XGAM, for use on personal computers,

has been supplied to the Office of Standard Reference Data, for sale to

the public. This is a further elaboration of the previously published

database XCOM.

A compilation of all available, experimental data on total photon

cross sections and attenuation coefficients for all elements has been

updated and revised, and published in Atomic and Nuclear Data Tables, 38 . 1-197 (1988). Software has been developed with which the experimental

data base can be accessed using a personal computer. A preliminary

analysis of these data, discussed in the Proceeding of SPIE Conference

911 (X-ray and VUV Interaction Databases, January 1988) indicates that

between 100 keV and 1 keV (except in the close vicinity of absorption

edges) there is satisfactory agreement between experimental values,

theoretical results of Scofield, and serai-empirical recommendations of

Henke. Between 1 keV and 100 eV the comparison maps out the regions

where the available theory becomes inadequate.

Cross Sections: Charged Particles (M. J. Berger & S. M. Seltzer)

A database has been completed pertaining to the elastic scattering

of electrons with energies between 1 keV and 1 MeV in all elements. The

underlying calculations involved the solution of the Dirac equation for a static screened (Hartree - Fock) Coulomb potential. Progress has been made

in extending these calculations above 1 MeV (where partial wave expansions

become prohibitively expensive) through the use of a WKB method. A set

of model cross sections for inelastic interactions of electrons with

water molecules, at energies from 1 MeV to 10 eV has been developed for use in microdosimetric transport calculations.

Preliminary versions have been developed of proton and alpha particle

stopping power and range tables, extending from 1000 MeV to 1 keV, taking

into account electronic, as well as nuclear stopping powers. These

tabulations are based on use of the Bethe theory (with shell corrections)

above 1 to 2 MeV, and using critically evaluated experimental stopping

powers at lower energies.

Digital Energy Subtraction for Biomaterials (C. E. Dick)

The technique of utilizing digital energy subtraction to investigate

materials of biological interest in the human body is continuing. Studies

are underway to determine the sensitivity of the method by imaging various

thickness water samples embedded in tissue equivalent plastic. At present,

155
Division 536, Technical Activities (cont'd.)

the use of photon beams with average energies of 75- and 150-keV allows

the detection of fluid thicknesses of approximately 1 mm in 5 cm thick

phantoms. Further experiments are underway to optimize the energies of

the photon beams and improve the sensitivity of the method for this and

other imaging tasks.

Medical and Industrial Radiography (C. E. Dick)

Several programs are continuing to investigate topics concerned with

x-ray imaging for both medical and industrial applications. A collaborative

effort is underway to investigate the properties of a new class of x-ray

imaging medium, photostimulable storage phosphors. Experiments have been

initiated to investigate storage of x-ray image information in deep traps

in these materials which can be released on demand by interrogation with

an infrared laser. Preliminary results indicate that the process can be

successfully modeled by a Monte Carlo calculation of the charge storage

and retrieval process. Presently, the calculated and experimentally

measured data agree to within 10 percent x-ray excitation energy of 662-

keV. Data are also being gathered on the fading of the storage screen

and the lifetime of the stored image information.

An experiment has been completed to measure the effect of metallic

x-ray intensifying screens used in industrial radiography. The relative

photographic effect for aluminum, copper, and lead screens has been

measured as a function of the screen thickness and screen location (front

or back) for both the front and back emulsion of a typical x-ray double

emulsion film. At present the measurements are limited to a photon

energy of 662-keV. The process has been modeled by a Monte Carlo calculation

based on the ETRAN model which includes geometrical factors. The experimental and calculated data agree to within 5 percent indicate the relative

energy deposition in the film emulsion by electrons generated by photon

interactions in the metallic foils.

Portable Dental X-Ray Imaging Systems ( J . H. Sparrow, M. R. McClelland,

& J. W. Motz

)

The Radiation Interactions and Dosimetry Group has completed prototypes

of portable, dental x-ray imaging systems for field use by the U.S. Army.

The smallest prototype, which weighs approximately 16 pounds, is an analog imaging system consisting of a carrying case with a ruggedized six

pound, 70 kV x-ray source, batteries, and self -developing dental x-ray

films. A second prototype, which weights approximately 45 pounds, is a non-film system consisting of a carrying case with a real-time intra-oral

x-ray image sensor, a frame - grabber , a monitor, and the 55 kV x-ray

source. This second system may be used either in an analog or digital

format, and images may be instantly displayed on the monitor or stored on

tape, floppy disks, or different types of solid-state memories. Future

efforts in the program will be directed toward improvements in the x-ray

156
Division 536, Technical Activities (cont'd.)

intra-oral image sensor, in the portable x-ray source, and in the image

storage and display equipment.

Dosimetry of High-Energy Photon and Electron Beams (L. J. Goodman,

C. G. Soares, & R. Loevinger)

It is important to test the adequacy of current clinical protocols

to provide accurate photon and electron dosimetry for applications to

high-energy cancer therapy. These tests would compare measurements made

with ionization chambers calibrated according to prescribed protocols to

measurements performed with an absorbed-dose calorimeter. We propose to use the electron beam of the NIST racetrack microtron to produce collimated

beams of high-energy protons and electrons, which will simulate those

applied clinically to treat cancer.

A separate beam line will be used to transport the electron beam to

a transmission window from which it will enter a target, filter, and

collimator assembly. The electron beam current and energy required will

range from about 180 nA at 5 MeV to about 1 pA. at 35 MeV. The apparatus

which has thus far been designed and constructed includes the target,

filter, and collimator assembly, a special alignment and support table

for this assembly, and a rolling table with a remote-controlled translation

platform for positioning the phantoms and dosimeters. Several of the

beam- line components have been ordered. Funding is being sought to

purchase a water phantom with a three-dimension, remote-controlled translation system and its computer for control and data analysis, to purchase

the remaining beam- line apparatus, and to install the equipment in a shielded room adjacent to the accelerator.

Absorbed Dose Calorimetry (S. R. Domen)

Medical and industrial applications of ionizing radiation are quantified

in terms of the physical quantity absorbed dose, which is the energy

absorbed per unit mass in the material of interest. The calorimeter,

which measures absorbed energy in terms of the temperature rise, is the

logical standard of dose. NIST has developed a series of calorimeters as part of a program to develop reliable national measurement standards for

absorbed dose. One of these NIST calorimeters, the water calorimeter,

which measures the temperature rise due to radiation directly in water,

has aroused much interest and has been studied in a number of standards

laboratories and universities. One of the persistent problems, which has

not received adequate attention, is the effect of convection on the

accuracy of temperature readings by the tiny thermistors. An experiment

was devised to study this phenomenon using controlled flow past thermistors

operated at various power levels. The results of this experiment will

allow water calorimeters to be operated at room temperature without loss

of accuracy because of concerns about convection. A new model of a highpurity water calorimeter has been designed, which is also based on

157
Division 536, Technical Activities (cont'd.)

calculations of the effects of materials other than the high-purity

water. Preliminary work has been successfully completed on the fabrication

and assembly of micro-bead thermistors within thin glass capillaries, which

are to be the temperature sensors. Reports on these works are in press.

Preliminary tests of a calorimeter made of A-150 plastic (a tissue

substitute) have shown adequate behavior except for thermal drifts apparently

caused by contact potentials at the connectors. Connectors with goldplated contacts are being prepared. The completed calorimeter will be

tested in the NIST 60 Co beam for comparison of calorimeter and ionizationchamber measurements. A similar comparison will be made at another

institution using a beam of 15-MeV neutrons.

Development of Dosimetry Standards for Neutron Therapy (L. J. Goodman,

D. M. Gilliam, S. R. Domen, J. J. Coyne, & R. S. Caswell)

Neutron radiation therapy is being clinically tested at several

cancer treatment centers in the United States and at other centers worldwide. To facilitate the exchange of clinical information between treatment

centers, it is essential that the U.S. neutron dosimetry standards be

accurate and consistent with the international standards system. The

dosimetry program, sponsored by the National Cancer Institute, aims at

improving the accuracy and consistency of absorbed-dose measurements for

neutron therapy by developing national dosimetry standards and providing

improved data on neutron interactions in tissue and tissue-like materials.

NIST will provide these standards as it has provided and continues to

provide similar standards for photons and electrons.

Tissue-equivalent ionization chambers, in combination with lowneutron- sensitivity gamma-ray dosimeters, are accepted as the most reliable

instruments for clinical neutron dosimetry. We have under study such a system of instrumentation. Its accuracy will be assessed by comparing it

to other instruments of the same type and of different types. Thus far,

the NIST ionization chambers have been compared to a similar set of

dosimeters from the Bureau International des Poids et Mesures and to

instruments of other national standards laboratories. At NIST we have

also favorably compared the ionization chamber dosimetry method of measuring

neutron kerma to a determination of this quantity made from measurements

of neutron fluence combined with calculated kerma factors. This latter

comparison will be repeated using monoenergetic 15-MeV neutrons, an energy more appropriate for developing a neutron standard. A comparison

between the ionization chamber method and a tissue-equivalent calorimeter

is also planned using the intense 15-MeV neutron beam available at a remote site. Agreement between the three independent methods and with

the measurements of other standards laboratories will assure the accuracy

and consistency of the U.S. dosimetry standards for neutron therapy.

158
Division 536, Technical Activities (cont'd.)

Theoretical support for the experimental standards program is aimed

at improving the physical data and correction factors needed to interpret

the physical measurements. These data and factors include the mean

energy required to produce an ion pair, kerma factors, and mass stopping

powers

.

Reactor Dosimetry and Consultation at AFRRI (L. J. Goodman, R. B. Schwartz,

E. D. McGarry, D. M. Gilliam, & C. M. Eisenhauer)

Work performed under this contract with the Armed Forces Radiobiology

Research Institute (AFRRI) aims to improve the accuracy and long-term

consistency of neutron and gamma-ray dosimetry at the AFRRI research

reactor by consultations with a group of NIST scientists and by providing

specific dosimetry services. This effort is needed to support the radiobiological studies at AFRRI because of the relatively frequent (approximately

2-year) turnover of scientific military personnel at AFRRI. It is essential

that accurate dosimetry methods support the radiobiological experiments

in order to relate this research to similar work at other laboratories.

During the past year we have designed and installed a 252 Cf radiation

source housed in a specific shield for use in checking the large variety

of ionization chambers at AFRRI for proper operation. This source, which

emits neutrons by spontaneous fission, is necessary to test the neutron

response of the dosimeters used at the AFRRI reactor. Benchmark measurements

of the AFRRI ionization chambers have begun and will be continued after

needed modifications to the check-source cask have been completed.

An improved monitoring system for the radiation fields produced in

the reactor exposure rooms have been designed. The fission chambers

needed to implement this system were designed, constructed and installed.

Testing and calibration of these chambers is in progress.

To verify the accuracy of the AFRRI reactor dosimetry, and as a training

exercise for new military dosimetrists at AFRRI, a comparison of neutron

and gamma-ray dosimetry in free air and in two sizes of monkey phantoms

was carried out. This work compared the instruments, measurement techniques,

and calculation procedures of the NIST and AFRRI scientists.

Personnel Dosimetry (C. Soares & M. Ehrlich)

M. Ehrlich developed a method for estimating the new operational

quantity, directional dose equivalent, with existing personnel dosimeters

having energy- and angle-response functions different from this operational

quantity. The efficacy of the method was demonstrated for one personnel

dosimeter for which suitable response data were available. A paper on

this subject was presented at a seminar at the Physikalisch-Technische

Bundesanstalt in Braunschweig. The full text of the paper will appear in

159
Division 536, Technical Activities (cont'd.)

the Proceedings of this seminar, to be published in Radiation Protection

Dosimetry

Further activities of M. Ehrlich in radiation-protection dosimetry

relate to work on two committees of the International Organization for

Standards (one dealing with radiation fields for the calibration of

radiation-protection instruments and the other with performance characteristics of photographic personnel dosimeters) and work on a committee

of the American National Standards Institute, dealing with dosimetry

quantities for use in radiation shielding.

Work on revision of ANSI Standard N13.ll, "Personnel Dosimetry

Performance - Criteria for Testing" continued, with C. Soares attending

three meetings of the working group. As part of the proposed testing of

angular dependence of dosimeter response, experiments were initiated on

the feasibility of such tests utilizing the aid of guest-worker C.-Y. Yu

of Taiwan Power (ROC) . Comparison of dosimeter response of the Panasonic

802 dosimetry system with the ICRU 39 quantity directional dose equivalent,

which is the proposed testing quantity, are being performed as a function

of photon energy.

Standard Monoenergetic Electron Beams (C. G. Soares)

NIST has been requested by the radiation protection community to

establish standards for and assist in the development of methods of

measuring the beta-particle radiation fields that are found in nuclear

power installations. Beta-particle detection instrumentation is currently

being calibrated using only broad- spectrum radionuclide sources. In

order to determine instrument response as a function of energy in detail,

NIST has developed a set of accelerator-produced nearly monoenergetic

electron beams. The beam monitoring and control system developed in FY 86

has now been tested at the higher electron energies (1-2.5 MeV) and found

to perform satisfactorily. A full report on the system as well as results

of its use is in preparation.

High-Energy Nearly Monoenergetic Photon Calibration Facility

(C. G. Soares & R. J. Biss)

Work was resumed on development of this facility which supplies a need expressed by the Radiation Protection community for testing instruments

used for surveying areas where personnel are exposed to the high-energy

photons (~6 MeV) produced by activation of cooling water in power reactors.

The NIST facility uses the 3 MV positive ion accelerator to produce 6-7

MeV photons via the 1

9

F(p

,

ay )

1

6

0 reaction. Source usefulness has been

limited previously by low output dose rate (0.2 mGy/h) . By raising the

incident proton energy from 2 to 2.7 MeV, it has been possible to increase

this maximum dose rate by about a factor of five. Maximum beam currents

have been limited to about 10 /iA; work is now under way to design a

160
Division 536, Technical Activities (cont'd.)

moving target assembly to allow more proton current to be used and improvements to the accelerator are in progress to achieve higher beam currents.

A key focus of the current work has been to compare dose-rate mea- surements using several different systems. Previously, with the low

dose-rate limitation, only thermoluminescence dosimetry (TLD) measurements

were possible. With the higher dose rate, ionization chamber measurements

have now also been made. Comparisons between these two measurements, and

the results of spectral measurements from unfolded Nal pulse height

spectra (described elsewhere) are in progress.

Dosimetry of High-Energy Electron Beams (J . C. Humphreys)

Work continued on the development of methods to characterize and

calibrate high- intensity electron beams in the energy range of 10-40 MeV.

Preliminary designs include an aluminum multi-foil array calorimeter with

a high-speed multichannel data analysis system that can measure a complete

depth-dose profile from a single pulse (or short pulse train) irradiation.

These results will provide information on the integrated total dose, dose

rate and electron energy (calculated from the extrapolated range) . The

data acquisition system and calorimeter will be compact and light so as

to be easily transported to an industrial accelerator facility for calibration of its electron beam. These accelerators are becoming more numerous and are being increasingly utilized for medical product sterilization, and radiation hardness and polymer modification testing of electronic

devices. At present, dosimetry is performed with passive systems (such

as TLDs or dye films) that are calibrated with 6

0

Co gamma rays. Direct

calibration of the electron beams with calorimeters would reduce the

uncertainties in the dosimetry measurements as well as provide evidence

as to whether the response of the passive systems is the same for electrons

as for gamma rays

.

C . Chemical Interactions and Dosimetry Project

Radiation Chemistry of Aromatic Molecules (M. G. Simic, L. R. Karam, M.

Farahani & M. Al-Sheikhly)

Aromatic molecules play a major role in the mechanisms of direct

action of radiation on biological targets. Mechanisms of radiation on

the ring opening of benzene were unraveled and a new method for discrimination of metabolic (mucondialdehyde ) and free radical processes (hydroxymucondialdehye) involving benzene molecule was developed. It was also

shown that benzene may induce free radical processes and generate *0H

radicals in muscle tissue in the absence of radiation and visible light.

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Division 536, Technical Activities (cont'd.)

Lipids (M. Al-Sheikhly & M. G. Simic)

Mechanisms of radiation induced autoxidation of lipids are being

studied by pulse radiolysis and oxygen uptake experiments, utilizing

oxygen electrode in aqueous solutions. Since irradiation of aqueous

solutions provides a definable number of initial reactive species, it is

possible to measure accurately the length of chain reactions. Pulse

radiolysis measurements provide kinetic and spectroscopic parameters of

the relevant lipid transients, and the reactions which lead to product

formation

A novel method based on radiation induced uptake of oxygen was developed which allows discrimination of oxidative mechanisms (e.g.,

Russell, Bennett).

Antioxidants and Radioprotectors (E. P. L. Hunter, S. Jovanovic, &

M. G. Simic)

Antioxidants and sulfhydryls act as radioprotectors and anticarcinogens

and in both cases the mechanism of action is being studied. The impact

of this work is also of significance in food preservation and human

physiology. NIST is the only institution in the U.S. dealing with kinetic

aspects of antioxidants. The redox potentials of radioprotectors and

physiological antioxidants are being investigated.

Deoxvribosephosphate Modification by Ataxia Telangiectasia Cells

(L. R. Karam, M. G. Simic, W. Franklin, & T. Lindahl)

Cells from patients with Ataxia Telangiectasia (AT)

,

a disease

characterized by an accelerated build-up of damage caused by aging, show

extreme sensitivity to ionizing radiation and other free-radical producing

agents. Extensive DNA strand breakage, and a failure of these cells to

delay DNA replication immediately after irradiation so that DNA damage

may be repaired, suggested a study of an enzyme deficiency in this disease

as a possible venue in the further study of biomarkers and radiationinduced DNA damage.

The reaction of AT cell lysates with nick translated DNA substrate

was observed to alter the deoxyribosephosphate moiety. AT lysates were

found to induce an adduct reaction with a free phosphate group (observed

by both HPLC and GC-MS) , at a DNA strand break as well as in solution,

which may present a blocking point to DNA repair. The potential of using

this modified phosphate as a biomarker of radiolytic and non-radiolytic

(active oxygen) damage has yet to be determined.

162
Division 536, Technical Activities (cont'd.)

Post Irradiation Dosimetry (PIP) (L. R. Karam, D. S. Bergtold, & M. Siraic)

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 imports/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.

Accidental exposure of personnel to radiation has occurred in some

cases, without an adequate on-line dosimeter being present, accentuating

the need for the development of novel concepts in real-time dosimetry and

PID for such circumstances. PID techniques should also be useful in

radiation therapy and in measurements of the dose received by the NASA

personnel exposed to cosmic showers and solar flares in space. The

possible presence of unique radiolytic products, URPs , or specific markers,

in the urine of irradiated patients or personnel in space (e.g., thymine

glycol, 5 -hydroxymethyl uracil, etc.) is under investigation.

The discovery of o-Tyr in irradiated chicken meat may be utilized

for the development of suitable PID for meats. Analytical procedures and

a separation methodology have been developed for determination of o-Tyr

in irradiated and non- irradiated chicken-breast meat. No measurable

(<0.1 ppm) quantities of o-Tyr were found in non- irradiated meats, while

in irradiated samples a linear yield-dose relationship was found. Carbon

tetrachloride (fat extraction solvent) was found to induce o-Tyr in

irradiated and non- irradiated meat. However, even under those circumstances

no o-Tyr was found in the water- insoluble fraction (~75 percent of protein)

after water extraction. Currently developing HPLC (liquid chromatography)

techniques for the separation and elucidation of modified amino acids

(primarily, ortho- tyrosine) by derivatization (Picotag) and non-derivatization methods (UV by reverse -phase HPLC) . Gas chromatography-mass

spectrometry have been used to measure quantities of o-Tyr in meats

exposed to free radicals by radiation and organic solvents which affect

02 metabolism in the mitochondria. Relative yields of the various isomers

of tyrosine formed by the irradiation of phenylalanine in the presence

and absence of 02 are being studied.

Chemical Dosimetry Mechanisms (W. L. McLaughlin, M. Al-Sheikhly,

M. Farahani, & M. Desrosiers)

Radiation chemical kinetics and steady-state radiolysis studies are underway to unravel the response mechanisms of new chemical dosimeters,

namely those that show promise for applications at intermediate and high

doses. Pulse radiolysis of dichromate dosimeter solutions and radiochromic

dosimeter solutions are presently explaining for the first time the

intermediate reaction yields of these organic and aqueous solutions and,

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Division 536, Technical Activities (cont'd.)

in fact, have provided important clues on how to enhance yields of the

ultimate chemical products that are used for the dosimetric analyses.

Most important of all, the kinetics studies have made it possible to

design more precise systems which are devoid of reciprocity failure (no

rate dependence) and have well-behaved temperature coefficients. The

next direction in these studies is to examine the reaction mechanisms of

selected solid-phase chemical dosimeters.

High-Dose Dosimetry Applications (W. L. McLaughlin, M. Desrosiers,

M. Farahani, & M. Al-Sheikhly)

Valuable quality-control is provided by dosimetry at high doses of

photons and electrons. Areas of application include the sterilization of

medical products, food preservation, rubber vulcanization, plastic and

electronics manufacturing, treatment of solid, liquid, and gas waste, and

the production of wire and cable, plastics, and a wide variety of industrial

products. High-resolution dose mapping at interfaces of different materials

is a particularly effective application of thin-film dosimeters developed

at NIST-CRR. A current cooperative project with the ADA deals with

interface dosimetry. Absorbed doses are measured at tissue - teeth , tissuebone and tissue-metal interfaces where clinical radiation treatment

planning involves oral cancers and requires an accurate determination of

dose to lesions as well as to healthy tissues. Similar treatment planning

applications are envisaged for the irradiation of heterogeneous anatomical

tissues, where radiation- treatable laryngeal, cranial, ocular, and bone

and bone-marrow tumors occur. Improved quality control is also achieved

by such dosimetry in the radiation sterilization of complex medical

devices (e.g., iv sets, syringes, and prosthetics).

Optical Waveguide Dosimetry (W. L. McLaughlin, M. G. Simic, B. Radak, &

W. Warasawas)

The concept of optical waveguides combined with radiochromic dyes was applied to spectrophotometry and to pulse radiolysis, in order to

enhance the sensitivity of these analytical techniques. New approaches

involving kinetic spectroscopy were developed in collaboration with the

Boris Kidric Institute in Yugoslavia and allow pulse radiolysis examination

of radiation- induced reactions in solutions using low doses of flash x- rays in single or multiple short pulses (<1 ns) . A broad range chemical

dosimeter for real-time steady-state or pulsed fields of electrons,

photons or neutrons was developed to measure doses as low as 0.005 Gy,

and this innovation was honored as one of five R&D (IR-100) awards to

NIST in 1988.

164
Division 536, Technical Activities (cont'd.)

Reference Chemical Dosimeters (W. L. McLaughlin, B. M. Coursey, M. Farahani

,

M. Al-Sheikhly, J. C. Humphreys, D. Hocken, M. Hussmann, L. Sheahen, & S. Monaco)

Aqueous and organic chemical dosimeters were introduced, both as standard reference materials and as reference standards for calibration

of radiation sources of industrial and national laboratories. A major

paper was published on the radiation chemical yields of a potassiumsilver dichromate dosimeter which, by means of appropriate chemical

additives, was sensitized eight-fold, in order to overlap the classic

Fricke dosimeter. This work thus extends the dose range of aqueous

reference dosimetry by dichromate from 0.3 to 50 kGy. The response

mechanisms of this new dosimeter were investigated and are explained in a publication in preparation. In addition, a new class of reference radiochromic organic solutions were introduced as SRMs and are in the final

test stages. These systems are presently being reported on in the scientific

literature and cover an exceptionally wide dose range (0.5 to 106 Gy),

for use in industry, medicine, agriculture, and radiation protection.

New Dosimeter Film Developments (W. L. McLaughlin, M. Al-Sheikhly, &

A. Miller)

Several new types of radiochromic films have been added to the

stable of thin- film detectors, which can be used conveniently for measuring

high-resolution dose distributions over wide dose and dose-rate ranges.

Such films are useful especially in electron-beam dose mapping in industrial

and clinical applications. The new films include the following: dyed

cellulose diacetate (10 4 - 106 Gy); high-density polyethylene (5xl0 4 - 5xl0 6 Gy); dyed polyvinylbutyral (5xl0 3 - 5xl0 5 Gy); green cellophane

(5xl0 3 - 5xl0 4 Gy); a propriety film coating from GAF Corp. (2X10 1 - 5xl0 3 Gy) . Papers have been published or are in preparation describing

all five of these systems and their utilities in providing radiation

diagnostics and quality control. Four of them are now beginning to be

marketed successfully by private enterprise for specialty purposes, and

the last one is especially promising because it is unique in its sensitivity

and versatility.

D . Radiation Measurement Services Project

X-rav and Gamma-rav Calibration and Measurement- Assurance Services ( J . T. Weaver, P. J. Lamperti, & E. L. Bright)

Calibration services for x-ray and gamma-ray measuring instruments

continue at an increased rate. The number of TLD badge irradiations has

increased again this fiscal year. The documentation of the NIST calibration

procedures for x-ray and gamma-ray measuring instruments , NBS SP250-16,

has been published. The documentation of the NIST calibration procedures,

equipment, standards and history for the brachytherapy sources, is in the

165
Division 536, Technical Activities (cont'd.)

final stages of revision. Final publication will be in the NBS Special

Publication 250 series.

The Hewlett-Packard data-acquisition system used with the x-ray

instrument calibration ranges is obsolete and no longer supported by HP,

and a breakdown would interrupt the x-ray calibration services. As a result, work continues in an effort to interface the DEC 1123 minicomputer

with a current-model HP 3497A data-acquisition system using an IEEE-488

bus connection instead of a serial input. The DEC would then be used to

control essentially all aspects of the instrument calibration.

All three NIST free-air standards were compared with each other in

their overlapping energy ranges. Agreement was between 0.5 percent and

1 . 0 percent

An experimental technique for measuring the air attenuation correction

as a function of x-ray energy was designed. Data for the higher energy

x-ray beams (those used with the 300 kV x-ray range) have been taken and

analyzed. The experiment continues for the lower energy x-ray beams (100

kV x-ray range) . These new data will be the basis for the corrections to

be applied to the NIST free-air standards.

Additional assistance in the use of the 60 Co and 137 Cs gamma-ray

ranges continues to be provided to other agencies and industry. Assistance

was also provided to Group physicists for their continuing study of the

intensifying effects of metallic screens in industrial radiography.

High-Dose Radiation Calibration Services ( J . C. Humphreys & D. Hocken)

Documentation of these services has been developed as NBS Special

Publication 250-11: "Dosimetry for High Dose Applications". This report

describes in detail the various services available for the standardization

of high absorbed dose measurements of ionizing radiation (photons and

electrons only) . It describes the various irradiation facilities employed,

the dosimeter handling and analysis procedures and assignment of uncer- tainties to all aspects of the services . The report is available for

general public distribution and has been sent to over 450 interested

persons so far. During the past year about 300 calibration irradiations

and measurement services were performed for industrial radiation processing

facilities, national laboratories, universities, other government agencies,

and other users at NIST. Steamlining of these services and improved

statistical analysis of calibration data have enhanced the efficiency and

reproducibility of the services and have reduced the "turn around" time

for calibration requests.

166
Division 536, Technical Activities (cont'd.)

High-Energy Electron and Photon Measurement- Assurance Services

(C. G. Soares & E. L. Bright)

Users of medical linear accelerators for cancer teletherapy need

assurance that their machines are delivering the required radiation

dosage. To meet this need, NIST offers a measurement assurance service

that involves mailing to the users passive dosimeters to be irradiated in

a prescribed geometry and returned to NIST for evaluation of the absorbed

dose delivered. For this service, ferrous - ferric (Fricke) dosimeters are used at present. There were three mailings of Fricke dosimeters in FY 88,

involving 50 sets of participants, and a total of 182 dose interpretations.

Two batches of dosimeters were prepared. In order to conserve time, and

thus cost to the participants, the tests are administered simultaneously

to as many participants as the batch size permits. To help in preparing

summary reports and identifying trends, the test results from the entire

twenty-year history of the service have been entered into a data base.

Documentation on the NIST procedures for the Fricke measurement assurance

service is complete and has been published. It was distributed to all

present and past participants of the study and will be part of the package

sent to prospective new users.

Beta-particle Source Calibration and Associated Measurement-Assurance

Services ( J . S. Pruitt)

The NIST extrapolation chamber has been used to calibrate four

ophthalmic applicators for absorbed dose to water at the applicator

surface. Each calibration was accompanied by quality assurance measurements

with NIST applicator SN0258.

The PTW extrapolation chamber has been transported to the Battelle

Pacific Northwest Laboratories, in Richland, WA, to calibrate two strontium

beta-particle sources purchased by the National Voluntary Laboratory

Accreditation Program (NVLAP) for use in that laboratory. The PTW chamber

has also been used for several measurements in this laboratory, including

mapping the two NIST strontium sources, with and without a flattening

filter and measuring the perturbation introduced into current measurements

by a ring used to hold filters added to the chamber face to simulate skin

depth

.

The parallel plate ionization chamber purchased for dissemination of

NIST beta-particle calibration (PTW#2047) has been shown to be erratic

and not trustworthy for that purpose. The reason for this erratic behavior

has not yet been determined, but a second PTW extrapolation chamber has

been used in its place for long-distance comparisons between NIST strontium

and thallium sources and similar sources at the Idaho National Laboratory

in Idaho Falls.

167
Division 536, Technical Activities (cont'd.)

Performance Evaluations of POD Radiological Inspection Systems (20 keV to

16 MeV) (J. H. Sparrow)

At the request of the Department of the Navy, this program carries out

the following tasks:

1) measure and calibrate, every 12 to 18 months, the x-ray outputs of

approximately seven 16 MeV Linear Accelerators used for radiological

inspection systems by DoD and their contractors.

2) propose radiological procedures to determine image quality achieved

during production and refitting inspection of missiles; approximately

every 6 to 12 months, perform an on-site audit of the radiological image

quality achieved at the various DOD facilities and product manufacturers;

participate in the development of radiological penetrameters which are used as image quality indicators; and participate in new design of a test specimen used to evaluate both image quality and system performance

for high energy CT radiological inspection systems;

3) assist in the integration of old and new radiological methods, (film,

real-time, and tomography), so that image quality is adequate for routine

inspections

4) propose radiographic equipment which can be used at the DOD facilities

and vendors to monitor the x-ray beam energy fluence and beam position;

and assist in the implementation of that equipment.

Department of the Navy Dosimetry Calibration Program

(J. T. Weaver & E. L. Bright)

The Navy thermoluminescence dosimetry (TLD) measurement-assurance

program, sponsored by the Naval Sea Systems Command, continues. NIST

receives boxes of 15 TLDs from the Naval Surface Weapons Center and

irradiates 12 of them to known exposures with 137 Cs gamma rays. The

boxes are dispatched to designated Naval facilities for readout, and the

results are returned to NIST for analysis and comparison to NIST exposures.

The results are sent to the sponsoring agency, and they schedule a retest

or recalibration for any TLD-readout instruments that indicate exposures

differing from the NIST exposure by more than 13 percent. About 312

boxes, containing 3744 exposed dosimeters, were dispatched during FY 88.

Also included on this project is exposure of an estimated 144 badges for

the Naval Medical Command and completing a calibration of an AN/UDMlA

calibrator. Several Victoreen R-meters and associated chambers were also

calibrated under this project.

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Division 536, Technical Activities (cont'd.)

III. NEUTRON INTERACTIONS AND DOSIMETRY GROUP

The Neutron Interactions and Dosimetry Group develops and applies

well-characterized neutron fields and related capabilities for neutron

dosimetry methods evaluation and standardization, for detector development

and calibration, and for reaction cross section measurements. Strong

involvement with outside organizations, both in the federal and private

sectors, includes many types of research and technology assistance programs

as well as leadership roles on national and international standards and

radiation policy making bodies.

Accomplishments for FY 88 are outlined below in titled paragraphs

under the five projects that define the group's activities. Major

participants and a scope statement are included for each project.

DOSIMETRY FOR MATERIAL PERFORMANCE ASSESSMENT (E. D. McGarry, D. Gilliam,

C. Eisenhauer, & G. Lamaze)

Dosimetry methods for monitoring the degradation of materials in

high fluence neutron exposures are diverse. This project provides some form of measurement assurance, standardization, or methods development

for nearly every approach to materials dosimetry employed in the United

States. Interlaboratory measurement cooperation including substantial

European participation are an important feature of this project.

1. Neutron fluence standards . These unique artifact standards are neutron sensors (activation foils generally) in which a radioactive

species relevant for dosimetry is induced by irradiation in a standard

neutron field. NIST maintains a variety of standard neutron fields to

supply such neutron fluence standards to customers under NBS SP 250

Calibration Services and to the Nuclear Regulatory Commission under a general consultation contract. These fluence standards provide benchmark

referencing for dosimetry measurement methods used in the nuclear industry.

Of particular interest is the production of 30-year 137 Cs in fissionable

foils of 2 3 8 U and 2 3 7 Np , and the production of 5. 7 -year 60 Co in copper by

30-day irradiations in the NIST 23

5

U Cavity Fission Source at the NIST

reactor. Although long half lives make these radioactive species difficult

to produce in standard neutron fields, irradiations are carried out at some expense because long half-lives are especially appropriate for longterm neutron fluence monitoring in power reactors.

2. NBS -Westinghouse cooperative agreement . In a move to improve

Quality Assurance (QA) methods associated with dosimetry procedures at

commercial power reactors, NIST and Westinghouse have begun negotiating a cooperative agreement. Under this agreement, NIST will review the mea- surement techniques for reactor neutron dosimetry at Westinghouse to

insure that direct measurement links exist with standard neutron fields

169
Division 536, Technical Activities (cont'd.)

at NIST. Westinghouse and NIST personnel have met and agreed upon important

elements of a written agreement. Efforts are already underway to investigate

some measurement discrepancies in power reactor data obtained with paired

uranium detectors (PUD) for neutron fluence furnished by NIST.

3 . Dosimetry benchmarking for the heavy section steel testing

(HSST) -program . NIST is helping the NRC benchmark fast neutron dosimetry

for an HSST steel testing program carried out by the Materials Engineering

Associates (MEA) Corporation at the University of Buffalo's Pulstar

Reactor. The focus of this activity is radioactive counting procedures

at the Idaho Nuclear Engineering Laboratory (INEL) where analysis of all

dosimetry involved in the MEA tests are performed. Comparisons of experimental dosimetry with neutron transport calculations were presented by

NIST at the 14th ASTM-E10 Radiation Effects on Materials Symposium, in

Andover, MA in June 1988.

4. Fission spectrum cross section of 9

3

Nb (n . n

'

)

9 3

Nb . Because of

its long half life (16 years) and a low energy threshold (1 MeV) , the

Nb(n,n') reaction is a candidate for long term neutron fluence monitoring.

One drawback has been the lack of adequate cross section information.

Now, in cooperation with the universities of Illinois and Arkansas, the

spectrum averaged cross sections of the niobium reaction have been measured

in the 235 U and 252 Cf standard fission neutron fields at NIST. Freefield neutron fluences at both irradiation facilities were established by

neutron source emission-rate calibrations at the NIST MnSOA Bath Facility.

5. Benchmark measurements in commercial power reactors . Efforts

continue to benchmark reference neutron dosimetry associated with fast

neutron exposures of critical structures at nuclear power plants. The

benchmark work focuses on both measurement of neutron exposures that cause embrittlement of steel and on the characterization of test reactor

neutron environments used to study embrittlement models.

NIST is assisting the Babcock & Wilcox (B&W) Owner's Group conduct a full

power cycle benchmark designed to check a variety of dosimetry methods,

e.g., conventional foil activation versus solid-state track fission-event

recorders. Paired uranium detectors (PUDs) , and lithium fluoride chips

gamma sensors, both developed at NIST, are also included in this comprehensive dosimetry technique comparison.

6. Power reactor mockups . Because of the complexity of the radioactive

environments in and near the core of commercial nuclear power reactors,

and because of the apathy that utilities have toward "other than mandatory"

measurements in operating power plants, it is necessary to develop and

use mockups of power reactors structures to ensure materials integrity.

For the most part, this effort is aimed at improving the agreement between

measurements and neutron transport calculations. NIST has been involved

170
Division 536, Technical Activities (cont'd.)

with two such international power reactor benchmarks: VENUS at a laboratory

in Belgium and NESDIP in Great Britain.

VENUS is core loading benchmark that was constructed to study neutron

leakage in the vicinity of the fuel corners of PWR reactor cores. NIST

assists in the characterization work itself as well as with QA of dosimetry

measurements. NESDIP is a reactor mock up of various ex-vessel reactor

cavities. Again, NIST is involved with benchmark referencing of interlaboratory dosimetry measurements.

7. Dosimetry calibration for White Sands pulsed reactors . Fastburst, Godiva-type reactors are used for electronic materials irradiation

damage studies. A visit was made to White Sands Proving Grounds, New

Mexico, by NIST personnel in January to arrange for NIST fission chamber

measurements in the leakage spectrum from the White Sands Pulsed Reactor.

These arrangements were later postponed because of licensing problems

with on-site fissionable materials at White Sands. Rescheduling is

expected early in FY 89. In the meantime preparations for these in situ

measurements continue including detector response calculations and design

of acceptable fission chamber mountings.

PERSONNEL DOSIMETRY (R. Schwartz, C. Eisenhauer, J. Coyne, & E. Boswell)

Standard neutron fields are developed and applied for calibration of

radiation protection instrumentation and for the investigation and testing

of new types of dose measuring techniques. Substantial responsibilities

in national and international dosimetry methods research focuses on

tissue dose modeling and tissue equivalent proportional counter measurements.

1. Calibration service . Approximately 40 neutron radiation protection

instruments were calibrated this year, the majority of them for nuclear

power plants. The remotely operated detector positioner continues to

operate well, minimizing exposure to personnel, speeding up data taking,

and improving accuracy.

2. Performance tests of radiation protection instrumentation . In a joint project involving Harwell and the National Physical Laboratory in

England, and the Naval Surface Warfare Center and Naval Research Laboratory

in the U. S., the properties of the new Chalk River "Bubble Damage Detector"

were investigated. The results of this work were sufficiently promising

that this collaboration will continue under the auspices of the Naval

Medical Command.

In an effort to understand the cause of the persistent slow drift in the

9" remmeters commonly used for neutron radiation protection measurements,

a detailed study was made of the behavior of the 3 BF proportional counters

used as neutron detectors in these instruments. It was discovered that

the drift is caused by an unfortunate combination of the somewhat unstable

171
Division 536, Technical Activities (cont'd.)

electronics in the remmeter instrument package, and the abysmal performance

of the proportional counter. A good counter (readily available from

other manufacturers) would eliminate the problem.

3. Calibration intercomparison . The international intercomparison

of remmeter calibrations among NIST, NPL (Great Britain), PTB (Germany),

and CEA (France) has been completed. Calibrations with bare and moderated

californium involved a conventional spherical remmeter and a totally new,

unique neutron survey meter (the Dineutron). Each laboratory determined

a calibration factor for these instruments using their own californium

sources and their own preferred calibration techniques. The results were consistent with the assigned uncertainties. The NIST values for the

Harwell monitor were within about 2 percent of the mean of the other

three values. For the Dineutron, the NIST values differed from the mean

by 6 percent, with an uncertainty of 6 percent. (The latter instrument

is very difficult to calibrate properly) . The results of this intercomparison are to be presented at the Conference on Radiation Protection and

Dosimetry in Florida, in November 1988.

4. Tissue equivalent proportional counter (TEPC) studies . In a joint program with PTB and the University of Saarlands, a detailed study

was made of the behavior of various configurations of TEPC's in the NIST

filtered neutron beams. The purpose of this investigation was to learn

how to improve the response of TEPC-based remmeters in the keV-to-100 keV

neutron energy range. These types of remmeters are under active development

at several laboratories in the U. S. and in Europe. It is recognized,

however, that their performance needs to be improved in the energy region

made accessible by our filtered beams. An immediate result of this study

showed that the neutron dose due to contaminants in the beams as measured

by the TEPC was in agreement with the predictions based on NIST 3 He and

proton recoil spectroscopy. This work also demonstrated that the NIST

filtered beams are, by a very significant margin, purer and of higher

intensity than those available elsewhere.

5. International standards writing . The ISO Draft Standard Proposal,

"Procedures for Calibrating and Determining the Energy Response of Neutron

Measuring Devices Used for Radiation Protection," has been completely

rewritten although further changes will have to be made. A draft of the

chapter on calibrations, for the forthcoming ICRU publication "Determining

of Dose Equivalents from External Radiation Sources - Part 3," has also

been completed.

6. Radiation protection policy committee work . C. Eisenhauer serves

as chairman of a sub-panel of the Science Panel of the Committee on Interagency Radiation Research and Policy Coordination (CIRRPC) . This

sub-panel is responsible for producing a report on the desirability of

planning for research on human health effects in the event of a nuclear

accident. J. Coyne serves on the High-LET subcommittee for CIRRPC. This

172
Division 536, Technical Activities (cont'd.)

subcommittee is writing a report which will outline a general research

program for all government agencies on the radiobiological effectiveness

of neutrons. A first draft of the report will be ready in September and

will be submitted for informal review to concerned American and European

scientists

.

7. Room scattered neutrons . A series of Monte Carlo calculations

have been performed to check out the simple model developed at NIST for

estimating room-return background. Calculated room configurations were varied from a spherical cavity, for which the model is rigorous, to a cubical cavity, a rectangular parallelepiped cavity, and, finally, to a parallelepiped with an open ceiling corresponding to the configuration of

the NIST calibration room. The simple expression for the fluence $r2 = A+Br2 where r is the source detector distance, works well for a cubical

room, but correction term proportional to r

A has to be added for the

configuration of the NIST room. Recent experimental results at NIST tend

to confirm this prediction, although the coefficient of the r

A term is so small that more careful measurements will be required. An invited paper

on this subject was given at the annual meeting of the American Nuclear

Society.

8. Air-scattered neutrons . Although the correction for air scattering

is estimated to be only a few percent in a typical NIST calibration of

neutron personnel instruments, larger corrections have been observed in

calibrations at other institutions. A definitive series of Monte Carlo

calculations of the fluence and spectrum of air scattered neutrons verified

earlier estimate of a 1 percent fluence correction at 1 meter for the

NIST Cf sources and U percent at 1 meter for the moderated Cf sources. A

paper describing these calculations was published in Radiation Protection

Dosimetry .

9. Microdosimetrv of radon and radon daughters . There is much

interest at present in understanding how cancer in the lung and bronchial

epithelium are produced by radon and radon daughters. We are studying

the physics of this process through microdosimetry. A new computer code,

"RADONA" (radon-analytic), has been constructed from our "analytic method"

code for neutrons. This code involves calculating an alpha-particle

slowing-down spectrum at the basal cell location based on an assumed

distribution of alpha-particle sources and anatomical geometry. From

this microdosimetric spectra and parameters are calculated. Calculations

have been carried out for a surface uniformly covered with 218 Po and

2 1

A

Po , with cells at depths such as 22 ^m. In addition, we are able to

calculate microdosimetric spectra and parameters for uniformly distributed

alpha sources in an organ.

10 . New standard field for testing radiation protection instruments . Calculations of neutron fluence spectra in spherical cavities with

various materials and neutron sources have begun as a first step in

173
Division 536, Technical Activities (cont'd.)

generating a calibration spectrum which is close to that observed in

maintenance areas of nuclear power plants. We are seeking a spectrum

which minimizes the dose-equivalent for neutrons above about 500 keV

Our present Cf and moderated Cf sources give 75 percent and 50 percent

above 500 keV, respectively. This provides encouragement that use of the

moderated Cf source in a cavity with some combination of Fe and CH2 will

give an acceptably low component of dose equivalent response above 500

keV.

NUCLEAR INTERACTION MEASUREMENTS (A. Wasson, R. Schrack, R. Johnson,

K. Duvall, & A. Carlson)

Jointly supported by DoE and NIST, this project pursues on a long

term basis accurate measurement and evaluation of standard neutron cross sections for nuclear technology. The major experimental work including

detector development is carried out at neutron time-of-f light facilities

associated with electron linacs at NIST and elsewhere, and at the NIST 3 MV positive-ion accelerator. This project coordinates all standard cross section evaluation efforts in the U.S.

1 . U-235(n.f) fission cross section from thermal to 1 keV . The

measurements of the neutron induced fission cross section for 235 U from

.02 to 1000 electron volts using the NIST electron LINAC facility have been

completed. This cross section, especially the integrals from 7. 8- to 11-

eV and from 100 to 1000-eV, is widely used as a standard to normalize

shape experiments. The present relative measurements were normalized at

the thermal neutron energy region. The cross sections agree within 3 percent with other recent measurements and show an important deviation

from the ENDF/B-V evaluation.

2. The standards evaluation for ENDF/B-VI . The standard cross sections to be used in the ENDF/B-VI evaluations are now available.

These standards, accepted by the Cross Section Evaluators Working Group

in May 1988, are the result of evaluations performed in a more thorough

and consistent manner than in earlier ENDF/B versions. The primary

effort focused on a simultaneous evaluation using generalized least

squares, R-matrix evaluations, and a separate procedure for combining the

results. This evaluation effort turned out to be more substantial than

anticipated. Under consideration are proposals for establishing meaningful

uncertainties in these evaluations.

3. Fifty years with nuclear fission, a conference . Preparations for

the NIST and American Nuclear Society to co-sponsor a conference to

celebrate the golden anniversary of the discovery of nuclear fission from

April 26-28, 1989 are progressing smoothly. General topics for the

conference have been selected by the program committee and approved by

the American Nuclear Society. The roster of invited speakers is nearly

complete, and the call for contributed papers has been issued.

174
Division 536, Technical Activities (cont'd.)

4. U-235 fission cross section from 3-to 30-Mev . In an effort to

improve the accuracy of the 235 U(n,f) cross section, measurements were initiated at the new target 4 facility at the Los Alamos National Laboratory

(LANL) 800-MeV proton accelerator two years ago. The fission reaction

rate is determined with a fast parallel plate ionization chamber designed

at LANL while the neutron fluence is being measured with an annular

proton recoil telescope whose properties were studied earlier at NIST.

Experimental tests, diagnostic studies, and preliminary cross section

determinations have been completed this year.

5. Response of the dual-thin scintillation neutron detector . The

Dual Thin Scintillator (DTS) is a unique neutron detector that is being

developed for improved neutron fluence and spectrum measurement. Current

attention has been directed towards understanding some details of the

detector response. A Monte Carlo code has been used to calculate the sum coincidence pulse-height response and detector efficiency in the 1 to 15

MeV energy region. The results indicate that the sum coincidence mode of

operation is superior for certain applications.

6 . A 2.5-MeV neutron source for fission cross section measurements . A 2.5-MeV neutron source has been established at the 100-kV, 0.5-mA ion

accelerator. Neutrons are produced by the D(d,n)He reaction with a yield

of about 3xl0 6 s' 1. The time -correlated associated particle method (TCAP)

is utilized for the neutron fluence determination and for neutron background

elimination. A fission chamber containing six UF4 deposits has been

designed for use in the 235 U(n,f) cross section measurement at 2.5-MeV.

7 . Measurement of the He-3(n.p) cross section from 1 eV to 750 keV . The 3 He/Xe gas scintillation counter has been used during the past year

to measure the 3 He(n,p) 3 H cross section in the neutron energy region from

1 eV to 750-keV using the NIST linac pulsed neutron source. These first

measurements used the 10 B(n,a) reaction as the reference standard.

Although the contribution from neutrons scattered from the thick walls of

the counter into the gas is large, it is believed that the cross section

can still be measured to within the desired 3 percent uncertainty for

this important standard cross section.

8 . Bulk material elemental assay with 2.5-MeV neutrons . A new

application of 2.5-MeV neutrons to measure the elemental composition of

bulk materials has been explored. The new technique uses the timing from

associated particles to detect prompt 7 rays as signatures of elemental

content. The aim of the research is to develop portable nuclear probes

for nondestructive identification.

9. Dosimetry for a 6 - to 7-MeV photon source . Dosimetry measurements

of a nearly monoenergetic 6 - to 7-MeV photon source developed at NIST for

radiation protection instrument calibration has been carried out by means

of Nal scintillation spectrometry. Spectrum-unfolding results indicate a

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Division 536, Technical Activities (cont'd.)

total air contribution of approximately 12 percent kerma from a continuous

distribution of low-energy photons extending up to 4.5 MeV

10. Data acquisition systems . The three Datacraft computers used

for data acquisition at the linac and the 3-MV positive-ion accelerator

for the past 13 years have been replaced. The new system consists of a Charles River Data System UV2403FT computer, MIZAR MZ9400 computer, and

AST Research Inc. Premium/286 computer connected by a high speed local area network. The system is operational but will require some additional

programming efforts.

RESEARCH AND TECHNOLOGY ASSISTANCE (all group members)

Research activities and technology assistance are strongly coupled

especially in neutron dosimetry. A multiplicity of institutional involvements, drawn to the group by unique irradiation facilities and measurement

capabilities, encourages a variety of attractive projects and unavoidable

responsibilities

1 . Benchmark measurement for criticality safety calculations . An

interlaboratory program aimed at resolving discrepancies between calculations

and measurements in nuclear criticality safety has been undertaken with

DoE sponsorship and NIST leadership. NIST will make measurements of

fission detector responses in the leakage spectra from spherical aqueous

moderators driven by 252 Cf neutron sources while LANL and ORNL will make

detailed calculations of these systems. Associated calculations at NIST

so far have included reaction rates for 239 Pu, 235 U, 238 U, and 237 Np at

four distances from a bare Cf source and from a source at the center of

4- inch and 6 -inch diameter spheres of water. These benchmark measurements

and calculations will help assure the validity in the future of calculations

that establish safe configurations of nuclear materials during processing

and storage.

2. Neutron lifetime measurement . In collaboration with scientists

of the Quantum Metrology Division, the University of Sussex, and the

Central Bureau for Nuclear Measurements, an ambitious experimental program

has been undertaken to improve previous measurements of the free neutron

lifetime. The half-life for this most fundamental example of nuclidic

disintegration is known to an accuracy of only ± 2.5 percent, while the

half-lives of less stable particles such as the pion and the muon are known as much as 1400 times more accurately. The first lifetime data

from this collaboration are expected between late August and early December,

1988 from measurements at the Institut Laue-Langevin cold neutron guidehall

in Grenoble, France. The experiment will next move to the new cold

neutron guidehall at NIST for more exhaustive measurements. The group so far has carried out the absolute efficiency calibration of the 10 B neutron

density monitor and will improve this calibration by means of a total

176
Division 536, Technical Activities (cont'd.)

absorption detector and an alpha- gamma coincidence calibration scheme.

Group personnel also have participated in the Grenoble measurements.

3. Capture cross section measurement in ISNF . Spectrum-averaged

cross sections for six reactions of interest in reactor physics have been

measured in the Intermediate Energy Standard Neutron Field (ISNF). The

ISNF neutron energy spectrum resembles a fast reactor spectrum, but with

much less complexity. The ISNF neutron fluence is determined by fluence

transfer from a calibrated 252 Cf fission source. The following spectrumaveraged cross sections were reported this year: 23 Na(n, 7 ) = 1.57 ± .10

mb, A5 Sc(n, 7 ) = 24.4 ± 0.8 mb, 59 Co(n, 7 ) = 36.3 ± 1.5 mb, 109 Ag(n, 7 ) = 23.8 ± 0.9 mb, 115 In(n,n') = 97.0 ± 2.5 mb, and 197 Au(n, 7 ) = 11 mb.

4. Fission chamber monitors at AFRRI . Neutron dosimetry at the

Armed Forces Radiobiological Research Institute's reactor exposure room

was put on a more stable basis by the installation and testing of two

fission chamber monitors. The AFRRI staff has learned to operate these

monitors confidently and have found them useful in resolving conflicting

readings among other dosimetry systems. Linearity tests of reactor

instrumentation, vs. NIST absolute fission chambers and tissue-equivalent

ionization chambers were carried out over the full range of reactor power

for the three most commonly used irradiation configurations.

5. Neutron spectrum characterizations for AFRRI . At the request of

the Armed Forces Radiobiology Research Institute (AFRRI), a spectrum

directory has been compiled that summarized calculated and experimental

neutron spectra and energy-deposition distributions ( "y- spectra" ) for

AFRRI exposure fields. In addition, we have advised them on the adequacy

of information on neutron and gamma-ray kerma in other fields for which

animal exposures have indicated an anomalously high relative biological

effectiveness

.

6. Neutron penetration in slabs . In order to help the U. S. Navy

estimate shielding requirements for personnel on submarines carrying

nuclear missiles, Monte Carlo calculations of neutron transmission through

slabs of iron have been performed. These calculations demonstrate that

the neutron penetration is insensitive to the position of a slab between

a localized source and detector. A scaling parameter was found that

relates the relative contribution to the lateral dimensions of the slab.

7. Reactor beam calibrations . Absolute fission chambers and fissionable isotope mass standards were employed to determine absolute

neutron fluence rates and improvement in the "capture flux" resulting

from installation of the Cold Source at the NIST Research Reactor. These

results influenced plans for further upgrading of the Cold Source.

8. Public knowledge and radiation emereencies . The NCRP Committee

on Radiation Exposure in a Nuclear Emergency created a task group last

177
Division 536, Technical Activities (cont'd.)

year to develop guidelines for improving public knowledge about radiation

exposure in order to enhance public response during a major radiation

emergency. The NIST representative on this task group prepared material

for the final report that identifies and briefly evaluates the pathways

by which the public receives information and forms a point regarding the

hazard of nuclear radiation before and during such an emergency. The

breadth of representation on this task group has also led to consideration

of a possible Radiation Index for the general public similar in concept

and application to the Air Quality Index developed by EPA. The effort is

to develop a compass and envelope of purpose for the index that will be

acceptable to various levels of radiation protection authorities and

endorsable by responsible federal agencies. This is a large order.

9. Mass assay of ultra-light fissionable deposits . Westinghouse

Research Center, Pittsburgh is working cooperatively with NIST to establish

mass scales for ultra-light fissionable deposits. These deposits, with

masses in the picogram or sub-picogram range, are used with mica Solid

Track Recorders (SSTR's) and represent a significant new dosimetry measure- ment technique. Currently achieved accuracy is better than five percent;

The goal is three percent or better.

10. Paired uranium detectors (PUDs) . In 1984, PUDs were provided to

Westinghouse Nuclear Technology Systems Division as backup dosimetry for

ultra- lightweight SSTR neutron dosimeters (see, item 9 above). These

dosimeters have been recovered and analyzed after an 18-month exposure in

the Diablo Canyon power reactor. The results show a presently unexplained

15 percent discrepancy between the PUDs and SSTRs. NIST will now re- irradiate several of the PUD/SSTR pairs in a carefully controlled experiment

in the NIST 23

5

U standard neutron field in an attempt to resolve the

discrepancy

11. LiF chip development and application . A lithium fluoride crystal

dosimeter package was returned to NIST after irradiation through a full

fuel cycle in the cavity surrounding the reactor vessel at the Oconee 2 nuclear power plant. The sample retained virtually perfect optical

quality, despite the heat and humidity of the environment. The gamma

dose recorded was comfortably within the accurately readable range. This

gamma dose data will be employed by the operating utility to confirm

calculations of gamma and neutron dose as they affect the reactor vessel

embrittlement and safe operating lifetime.

12. Rhodium dosimetry detector . Rhodium is an attractive neutron

fluence monitor because of the close correspondence of its neutron response

to the kerma muscle response function. In support of its use as a neutron

monitor, the spectrum averaged cross section has been measured at the

NIST Cf Fission Neutron Irradiation Facility. The results of five separate

irradiations yielded a cross section value of 768 ± 23 millibarns. This

178
Division 536, Technical Activities (cont'd.)

measured result disagrees with the calculated value by nearly 10 percent.

A paper for Nuclear Science & Engineering has been accepted for publication.

IRRADIATION AND CALIBRATION FACILITIES (E. D. McGarry, J. Grundl,

C. Eisenhauer, & E. Boswell)

Well-characterized neutron fields are built and maintained as permanent

irradiation facilities providing certified fluences of pure fission

neutrons, sub-MeV distributions, monoenergetic keV beams, and thermal

neutrons. Passive and active detectors of all kinds are exposed in these

neutron fields for response calibrations, for cross section measurements,

and for the investigation of new measurement techniques. A high intensity,

neutron-driven gamma field operates for special purpose measurements.

A multi-purpose fission rate measurement capability is centered

around the NIST "go anywhere" double fission chambers and the NIST set of

fissionable isotope mass standards (FIMS) . The Manganous Sulfate Bath is

the primary neutron source strength calibration facility for the U. S. Absolute neutron fluences for all fission-neutron-driven standard neutron

fields at NIST are derived from source strength calibrations at this

facility

.

1. Neutron source emission rate calibrations . NIST continues to

provide neutron source-strength calibrations at a quoted absolute accuracy

level of nominally 1.5 percent. For sources of strengths less than 1 x

10 9 n/s , international intercomparisons have validated this claim. The

latest such comparison was published in Metrologia in 1988. For sources

of larger strength, a "limited participation" comparison was accomplished

this fiscal year with National Physical Laboratory in Great Britain.

Final results will be reported in FY 89.

2. Cavity fission source operations . Efforts to improve cavity

fission source operations and calibration base documentation are continuing.

A new general purpose shield cave for high and intermediate level radioactive

components has been designed and shop work on the shield walls has begun.

When complete, this shield cave will greatly simplify irradiation operations

at the reactor thermal column. New documentation describing the complicated

path by which absolute fission neutron fluence rates are established are

in final draft stage.

3. Scattering corrections in the cavity fission source . Corrections

for neutron scattering in the hardware and irradiation samples of the

cavity fission source are under review. Existing corrections are based

on Monte Carlo calculations made by LANL for an earlier configuration of

the cavity fission source with a different Cd box and Al enclosure.

Furthermore, recent calibrations of solid state track recorders (SSTR's)

involve a significantly different irradiation sample assembly. Recalculation

of neutron scattering with the MCNP Monte Carlo code has yielded corrections

179
Division 536, Technical Activities (cont'd.)

for scattering in SSTR's that differ from the one calculated by LANL.

We, therefore, recalculated scattering corrections with the MCNP Monte

Carlo code. Corrections for scattering for SSTR's vary from - .006 for

the Ni reaction to + .018 for 235 U fissionable deposits.

4. MNSO,, bath facility upgrade . Upgrade of the MnS0A facility

continues. Current efforts aim at better gain stabilization of the

system at high counting rates by replacing one of the sodium iodide

crystals with a germanium- lithium (GeLi) detector. The GeLi detector has

been purchased and checked out and is in the process of being installed.

Temporarily, the system will have three rather than two sensors until

sufficient experience with the new detector has been acquired. The

current system is capable, with extensive monitoring of electronic gain

shifts, of long-term reproducibility with a systematic uncertainty level

of 0.35 percent (la). The upgraded system should do as well but with

considerably less effort.

5. Thermal neutron density standard . This NIST calibration service

was discontinued in FY 88 because it has been under utilized and because

the same calibrations can be better accomplished at the thermal column of

the NIST reactor.

IV. Radioactivity Group

Introduction

During the past year the Group has accommodated several perturbations

of staff and facilities while attempting (1) to maintain interactions

with diverse U.S. radioactivity-measurement communities, (2) demonstrate

Group competence internationally and assist in the convergence of the

standards of all nations for all pertinent radionuclides, (3) develop

improved measurement techniques and create national standards for newly

significant radionuclides, and (4) issue unique Standard Reference Materials

(SRMs). Selected examples are described briefly in the following sections.

Propagation of National Radioactivity Standards ( J . M. Calhoun, L. L. Lucas, and remainder of Group)

For over a decade the concept of demonstrated traceability for

radioactivity measurements, in the sense of measurers presenting their

values for sources before the official values are revealed, has been

accepted by the U.S. regulatory agencies concerned, and most other organizations, as an important element of quality assurance programs.

This demonstration requires that a national standard exists for the

radionuclide in question and that some mechanism exists for making a comparison, directly or indirectly, with it.

180
Division 536, Technical Activities (cont'd.)

Although in principle it is not required that a source shown to be

related to a national standard has been used to calibrate the measurer's

instrument, it is in practice usually desired. This implies that suitable

NIST Standard Reference Materials (SRMS) or equivalents from other suppliers

should be available. Towards this goal, the following actions took place

between August 1, 1987 and July 31, 1988:

Total radioactivity SRMs distributed 747

Short-lived SRMs supplied under the USCEA

program for nuclear medicine 232

Scheduled calibrations 21

Special measurements 19

Traceability tests for FDA,

NRC, and commercial firms 233

While the total number of SRMs has not declined appreciably this

year, a revised mode of operation requires that future productions con- centrate on reference materials which are unique to NIST and for which

there is at least moderate demand. Scheduled calibrations provide a way

of certifying existing alpha sources or short-lived radionuclides not

available as SRMs; special measurements offer even greater flexibility in

terms of activity level, impurities, or source configuration, and this is

reflected in their cost.

The programs with the U.S. Council for Energy Awareness (USCEA),

carried out with the assistance of two very able research associates,

have grown in significance. The stable program for nuclear medicine

offers a self-supporting mechanism for supplying radionuclides judged

significant by the major radiopharmaceutical companies to the entire

medical community. The increasingly ambitious testing program for nuclear

power now has 14 participants from that industry, in addition to a major

measurement service organization and the three companies supplying most

of the commercial calibration sources. Test samples this year, which

accounted for much of the marked increase in traceability exercises,

included realistic gas samples and uniformly spiked air filters.

The long-standing testing programs with the quality control laboratories

of the Nuclear Regulatory Commission (NRC) and the Food and Drug

Administration continued effectively, and plans have been made to re- activate the lapsed program with the Environmental Protection Agency.

181
Division 536, Technical Activities (cont'd.)

228 Ra Standardization (D. D. Hoppes & L. L. Lucas)

In experiments spanning five years previous discrepancies between

two activity-measurement methods for 228 Ra have been resolved and SRMs

prepared. These reference materials are important for accurate monitoring

of natural environmental radioactivity, for in some regions of the U.S.

228 Ra from the thorium decay series is more significant than 226 Ra from

the uranium series.

Activity measurements of 5.75-year half-life 228 Ra are difficult

because of the low beta-particle energies (average of about 10 keV) and

the high-energy contribution from daughter 6.13-h 228 Ac and subsequent

progeny. Rapid and simple chemical separations are complicated by the

presence of 3.6-da 2* Ra later in the chain.

Moreover, if one attempts to separate the 22 8 Ac, measure its activity

with high-efficiency liquid scintillators and its gamma-ray emission

rates with germanium spectrometers, and then compare gamma-ray rates for an equilibrium 228 Ra - 228 Ac source, there are two problems. Completely

clear separations are difficult and confusion can arise in interpreting

the liquid-scintillation measurements. As always, some fraction of the

lower-energy portion of the spectrum is masked by system noise. Usually

some estimate of counts lost in this region is added, or an extrapolation

to zero energy is made. In the 22

8

Ac decay almost every beta decay is

followed by conversion electrons or Auger electrons that add 50 keV or more to the equivalent beta-particle pulse. If this shift in the energypulse-height intercept is not appreciated in the extrapolation through

the region masked by noise, an error of several percent can occur.

In 1983, 228 Ra was extracted from 25-year-old purified thorium oxide

and repeatedly separated over a period of four months until the relative

activity of any progeny was 0.1 percent or less. Liquid scintillation

counting was used for early measurements, but the definitive calibration

came from gamma-ray measurements of progeny in growth over five years

with an efficiency-calibrated spectrometry system. The gamma-ray probabilities per decay used were those measured at the Physikalisch-Technische

Bundesanstalt , FR, using comparable spectrometry systems viewing known

masses of the (1.405 x 10 10 )-year 232 Th parent in equilibrium with 228 Ra.

Quantitative samples of calibrated solution, with an overall uncertainty

of less than 3 percent, have been prepared as SRM 4339 and will be available

for distribution shortly.

Development of the NIST 10 Be/9 Be Isotopic SRM (K. G. W. Inn, B. M.

Coursey, & J . D. Fassett)

NIST, in conjunction with the Oak Ridge National Laboratory and the

Accelerator Mass Spectrometry Community, is in the process of developing

182
Division 536, Technical Activities (cont'd.)

a beryllium isotopic SRM. The SRM is being developed to serve the

Accelerator Mass Spectrometry community as a reference for geochronological

studies being done in laboratories around the world. The final 1

0

Be/9 Be

isotopic composition is approximately 3 x 1CT 11

. The material will be

released when differences between NIST and ORNL mass spectrometric mea- surements are satisfactorily resolved.

Isotopic-Fractionation-Free Method for the Mass Analysis of Beryllium

Isotopes (K. G. W. Inn & J. D. Fassett)

NIST has developed a method which results in an isotopic-fractionationfree method of determining the 9 Be/10 Be isotopic composition. In the

absence of reliable standards and because beryllium has only one stable

isotope, the quantitative determination of beryllium isotopic composition

was not previously considered possible. The method developed utilized a combination of isotope dilution mass spectrometry for the isotopic

information, and inductively coupled plasma atomic emission for the total

beryllium content. The algebraic manipulation of the data results in an analysis which is independent of isotopic fractionation effects.

International Laboratory Intercomparison of Actinides in Human Tissue (K

.

G. W. Inn & W. S. Liggett, Jr.)

An intercomparison exercise for 239 Pu +

2 4

0

Pu in SRM 4351 (Human

Lung) and 4352 (Human Liver) included scientists from the United Kingdom,

United States, and Japan. The conclusions of the study were: 1) there were no significant performance differences among the participants, 2)

the data generated during the exercise was consistent with the data used

to certify the SRMs , and 3) combining the previous and new data sets

resulted in significant improvements in the precision and accuracy of the

certified values.

Methods Development for Radiochemical Analyses in Powdered Milk

(K. G. W. Inn & T. Gills)

Since the Chernobyl incident there has been increased interest in

the content of radioactivity in foodstuffs. To address the quality

assurance needs within the U.S. and around the world, NIST will begin to

develop radioactivity- in- foodstuffs SRMs in the near future. In preparation

for the certification analyses, the Office of Standard Reference Materials

supported the development of radiochemical methods for actinides and

gamma-ray emitters. The most important feature of the procedures is the

complete and quantitative combustion of the samples by dry ashing, wet

ashing with combination of strong acids, and final ashing in teflon jars

with microwaves.

183
Division 536, Technical Activities (cont'd.)

Gamma- ray Measurements of Natural -Matrix Ocean Sediment (K. G. W. Inn &

F. J. Schima)

NIST is in the process of preparing an ocean sediment as an environmental-level radioactivity natural-matrix SRM to address the oceanographic

community's quality assurance needs. Bottles of the prepared sediment

have been measured for photon-emitting radionuclides, with a total counting

time of 24 weeks. The data is being critically evaluated for interferences

and background effects and will be the first NIST efforts to determine

2 1

0

Pb and 2A1 Am by non-destructive photon spectroscopy.

Large Area X-Ray Source Measurements ( J . M. R. Hutchinson, P. A. Hodge,

& M. P. Unterweger)

Measurements were made with large-area 2 3

8

Pu sources to characterize

the response of the x-ray measuring and calibration system. Measurements

were made with a rectangular source 5-in x 8-in and a circular source 3-

in in diameter. The activity of the sources were determined by means of

2ttq particle counting and then x-ray counting efficiencies were determined

for source- to-detector distances from roughly 2cra to 35cm. A curve was fitted through the efficiency points for each type source, based on a modification of the analytic expression for a point source. Agreement

between fitted and experimental points was within one percent in all cases.

Radon Intercomparison of Basic Calibration Laboratories in the U.S. ( J

M. R. Hutchinson & R. Colie)

Reports of discrepancies in the basic calibrations of radon in major

radon quality-control laboratories prompted NIST to initiate an intercoraparison with four radon-measurement laboratories. A special ampoule was designed which could be inserted into a 5-in Nal(Tl) well detector and

the response relative to other ampoules determined. Ampoules were filled,

intercompared in the Nal(Tl) detector, and assayed by the four laboratories

and NIST. Results agreed for four of the five laboratories to approximately

two percent, but the value of one laboratory differed from the mean value

by seven percent.

Isotopic Fractionation Anomalies in Resonance Ionization Spectrometry

Observed in Molybdenum and Tin ( J . M. R. Hutchinson & W. F. Fairbank, Jr.)

Studies aimed at determining the validity of the isotope dilution

procedure in resonance ionization spectrometry (RIS) resulted in the

observation of anomalous isotopic ratios in samples of metallic molybdenum

and tin. Since the actual ratio was known, the result was puzzling at

first and brought into question the accuracy of RIS to measure isotopic

ratios. The effect appears to be at least partially due to the selective

ionization of odd isotopes in the laser steps when the transition is

184
Division 536, Technical Activities (cont'd.)

unsaturated. Both theoretical and experimental work aimed at resolving

this problem are being pursued.

International Comparison of 125 1 Activity Measurements (D. D. Hoppes)

The ability of laboratories in about 20 countries to produce equivalent

national activity standards of 125 1 was tested in a 1988 comparison

organized under the auspices of the Bureau International des Poids et

Mesures (BIPM) . This radionuclide is important for nuclear medicine, but

has photon radiations too low in energy for reliable comparison of national

calibrations with the ionization chambers of the present International

Reference System (SIR) at BIPM.

Aliquots of known mass were prepared at the Orszdgos Meresugyi Hivatal,

Hungary, from material supplied by NIST, and ampoules containing these

samples were distributed to participants by the Laboratoire de Metrologie

des Rayonnements Ionisants, France. Measurements at each participating

laboratory were performed on about June 15 in order to minimize comparison

errors due to present uncertainties in the half life.

The technique used at NIST was sum-peak counting, in which a peak

due to two cascade radiations detected simultaneously is compared with

the peak due to each detected singly in order to calculate the counting

efficiency.

A visiting scientist from the Studiecentrum Voor Kernenergie, Belgium,

used a high-efficiency Nal(Tl) well detector for the measurement, and

prepared a detailed report comparing calculated and measured efficiencies.

Daniel Golas and Donald Gray, research associates from the U. S. Council

for Energy Awareness, measured sources with the same two- thin-crystal

system used annually for the calibration of SRMs

.

The two NIST results differed by 0.49 percent, slightly more than

the combined uncertainty (approximating one standard deviation) of either

measurement. Data from other countries, including measurements by at

least three other methods, are now being evaluated at BIPM.

Reliability of Radioactivity Calibration Sources (D. D. Hoppes, J. M. R. Hutchinson, & F. J. Schima)

Ideally, a radioactivity source or solution obtained from a commercial

supplier or any other nation's standardizing laboratory should give an instrument efficiency calibration equivalent to material from NIST, with

a possible error consistent with the uncertainty assessed by the producer.

Three Group actions have addressed this point.

For several years, the SIR at BIPM has served as a comparative

repository for many national standards of gamma-ray-emitting radionuclides.

185
186
INVITED TALKS

Division 536, Ionizing Radiation

Berger, M. J., "Multiple Scattering Angular Deflections and Energy-Loss

Straggling in Electron Transport Calculations," 8th Course: Monte Carlo

Transport of Electrons and Photons Below 50 MeV," International School of

Radiation Damage and Protection, Ettore Majorana Centre for Scientific

Culture, Erice, Sicily, Italy, September 24-0ctober 3, 1987.

Berger, M. J., "Electron Stopping Powers for Transport Calculations," 8th

Course: Monte Carlo Transport of Electrons and Photons Below 50 MeV,"

International School of Radiation Damage and Protection, Ettore Majorana

Centre for Scientific Culture, Erice, Sicily, Italy, September 24-

October 3, 1987.

Berger, M. J., "Cross Sections for Bremss trahlung Production and ElectronImpact Ionization," 8th Course: Monte Carlo Transport of Electrons and

Photons Below 50 MeV, International School of Radiation Damage and

Protection, Ettore Majorana Centre for Scientific Culture, Erice, Sicily,

Italy, September 24-0ctober 3, 1987.

Bergtold, D. S., "Urinary Biomarkers of DNA Damage and Repair," University

of Pennsylvania, Fox Chase Cancer Center, Philadelphia, PA, June 16,

1988.

Bergtold, D. S., "Free-Radical-and Radiation- induced Damage to DNA";

"Measurements of Biomarkers for DNA Damage and Repair," Exclusive

International Symposium (only 30 top experts invited), Max Planck Institute,

Mulheim, West Germany, September 25, 1988.

Calhoun, J. M., "Radioactivity and Its Uses," Office for Special Services

and State Affairs, District of Columbia Public Schools, Washington, DC,

April 30, 1988.

Carlson, Allan D., "Thermal Constants and Recommended Average Values,"

Meeting at Oak Ridge National Laboratory on Constraints on the 23

5

U

Resonance Prescription, Oak Ridge, TN, February 24-25, 1988.

Carlson, Allan D., "Status of the ENDF/VI Standards," Cross Section

Evaluators Working Group (CSEWG) , Brookhaven National Laboratory, NY, May

10, 1988.

Caswell, Randall S., "Basic Data Necessary for Neutron Dosimetry," Sixth

Symposium, on Neutron Dosimetry, Munich, West Germany, October 13, 1988.

Colle, R. "Measurement Uncertainties in the Past, Present, and Future,"

1988 NCSL Annual Meeting, Washington, DC, August 15, 1988.

187
Division 536, Invited Talks (cont'd.)

Coyne, J., "Applications of Nuclear Physics to Radiation Dosimetry and

Neutron Radiation Biology," 8th International Summer School on Nuclear

Physics Neutron Physics, and Nuclear Energy, Varna, Bulgaria,

October 19-27, 1987.

Domen, S. R., "The Role of Water Parity, Convection, and Heat Conduction

in a New Calorimeter Design," National Research Council, Ottawa, Canada,

June 6-7 , 1988

Ehrlich, M., "Evaluating the Indication of Currently Available Personnel

and Environmental Dosimeters in Terms of Directional Dose Equivalent,"

Seminar on "Implementation of Dose - Equivalent Operational Quantities into

Radiation Protection Practice," Physikalisch-Technische Bundesanstalt

,

Braunschweig, West Germany, June 7-9, 1988.

Eisenhauer, C. M., and Schwartz, R. B., "Review of Scattering Corrections

for Calibration of Neutron Instruments," American Nuclear Society, Los

Angeles, CA, November 18, 1987.

Eisenhower, E. H., "The Status of National Measurement Quality Assurance

Programs," School of Public Health, Harvard University, Boston, MA,

May 13, 1988.

Eisenhower, E. H., "National Measurement Quality Assurance Programs,"

Health Physics Society Continuing Education Course, Boston, MA, July 5,

1988.

Eisenhower, E. H., "The National Quality Assurance Program for Personnel

Radiation Dosimetry: A Case History," Workshop and Symposium of the

National Conference of Standards Laboratories, Washington, DC, August 16,

1988.

Hutchinson, J. M. R. (with K. G.W. Inn, and S. J. Bright), "Low-level

Radioactivity Standards at the National Bureau of Standards," First

International Summer School, La Rabida, Huelva, Spain, September 28-

October 9, 1987.

Hutchinson, J. M. R. (with R. Colie), "Radon Measurements and Calibration

Standards," First International Summer School, La Rabida, Huelva, Spain,

September 28-October 9, 1987.

Hutchinson, J. M. R. (with W. F. Fairbank, Jr., K. G.W. Inn, J. E. Parks,

M. T. Spaar, and J. C. Huneke) , "Workshop on Advanced Laser Technology for

Chemical Measurement," National Institute of Standards and Technology,

November 4-6, 1987.

188
Division 536, Invited Talks (cont'd.)

Hutchinson, J. M. R. , "Traceability of Alpha-Particle and X-Ray Measurement,"

Conference to draft "Criterion for the Operation of Secondary Calibration

Laboratories for Health Physics Instrumentation," National Institute of

Standards and Technology, February 9-11, 1988.

Hutchinson, J. M. R., "Direct Analysis of Radioactivity in Solids,"

Department of Chemistry, University of Maryland, College Park, MD , April

1, 1988.

Hutchinson, J. M. R. (with W. F. Fairbank, Jr., J. E. Parks, M. J. Spaar,

and John C. Huneke) , "Investigation of Systematic Effects in SIRIS: Matrix

Effects and Anomalous Isotopic Ratios," Resonance Ionization Spectroscopy

and Its Applications, National Institute of Standards and Technology,

April 10-15, 1988.

Inn, Kenneth G. W. , "Closed-vessel-microwave Dissolution," 334th Annual

Conference on Bioassay, Analytical and Environmental Radiochemistry,

Berkeley, CA, October 4-9, 1987.

Inn, Kenneth G. W. , "Quality Assurance Check list for Radiochemistry

laboratories," American Chemical Society Southwest Regional Meeting,

Little Rock, AR, December 1-4, 1987.

Inn, Kenneth G. W. , "Interlaboratory Comparison of Actinides in Human

Tissues," Second International Conference on Low-Level Measurements of

Actinides and Long-Lived Radionuclides in Biological and Environmental

Samples, Akita, Japan, May 17, 1988.

Loevinger, R. , "The Role of the Water Calorimeter in High-Energy Medical

Radiation Dosimetry," Workshop on Water Calorimetry, National Research

Council, Ottawa, Canada, June 6, 1988.

McGarry, E. D., "Californium- 252 Sources Used for Standard Neutron Fields

at NBS , " 252 Cf Workshop, sponsored by Oak Ridge National Laboratory,

Garden Plaza Hotel, Oak Ridge, TN, April 13-14, 1988.

McLaughlin, W. L. , "Dosimetry for Industrial Radiation," Winter Meeting of

American Nuclear Society, on receiving ANS Radiation Science and Technology

Award, Westin Bonaventure Hotel, Los Angeles, CA, November 16, 1987.

McLaughlin, W. L. , "Role of Dosimetry in Quality Assurance," Engineering

Foundation Conference on Advancing Food Technology With the Irradiation

Process, Sheraton Hotel, Santa Barbara, CA, November 20, 1987.

McLaughlin, W. L. , "Quality Control in Industrial Radiation Processing,"

Office of Atomic Energy for Peace of Thailand Colloquium, Bangkok, Thailand,

March U, 1988.

189
Division 536, Invited Talks (cont'd.)

McLaughlin, W. L. , "Dosimetry in Agricultural Applications of Ionizing

Radiation," Thailand Department of Agriculture Seminar, Chaing-Mai,

Thailand, March 18, 1988.

McLaughlin, W. L. , "Sterility Control in Medical Supplies Sterilized by

Ionizing Radiation," Thailand Food and Drug Agency Seminar, Bangkok,

Thailand, March 25, 1988.

McLaughlin, W. L. , "Development of Radiochromic Personnel Dosimeter,"

Federal Emergency Management Agency Test Facility, Berryville, VA,

August 30, 1988.

McLaughlin, W. L. , "NBS Developments for Quality Control in Food Irradiation

by Means of Dosimetry, Calibration and Testing are Described," Department

of Energy Meeting on Food Irradiation Technology, Forrestal Building,

Department of Energy, Washington, DC, September 7, 1988.

Seltzer, S. M., "Cross Sections for Bremsstrahlung Production and for

Electron- Impact Ionization," 8th Course: Monte Carlo Transport of Electrons

and Photons Below 50 MeV, International School of Radiation Damage and

Protection, Ettore Majorana Centre for Scientific Culture, Erice , Sicily,

Italy, September 24-October 3, 1987.

Seltzer, S. M. , "An Overview of ETRAN Monte Carlo Methods for Coupled

Electron/Photon Transport Calculations," 8th Course: Monte Carlo Transport

of Electrons and Photons Below 50 MeV, International School of Radiation

Damage and Protection, Ettore Majorana Centre for Scientific Culture,

Erice, Sicily (Italy) September 24-October 3, 1987.

Seltzer, S. M. , " Applications of ETRAN Monte Carlo Codes to Some RadiationTransport Problems," 8th Course: Monte Carlo Transport of Electrons and

Photons Below 50 MeV, International School of Radiation Damage and

Protection, Ettore Majorana Centre for Scientific Culture, Erice, Sicily,

Italy, September 24-October 3, 1987.

Seltzer, S. M. , "Bremsstrahlung Production by Electrons: Cross Sections

and Electron- Photon Transport Calculations," Conference on High Energy

Radiation Background in Space, Sanibel Island, FL, November 3-5, 1987.

Simic, M. G., "Exactly What Radiation Does to Food Molecules," Advances in

Food Technology Engineering Foundation Conferences, Santa Barbara,

California, November 15-20, 1987.

Simic, M. G., "Electron and Charge - transfer Processes in Macromolecules,

Gordon Conference-Radiation and Macromolecules, Oxnard, CA, March 7-11,

1988.

190
Division 536, Invited Talks (cont'd.)

Simic, M. G., "Mechanisms of Free Radical Chemistry and Biochemistry of

Benzene," International Symposium on Benzene Metabolism, Toxicity and

Carcinogenesis, Chapel Hill, NC , March 14-16, 1988.

Simic, M. G., "Superoxide Radical Elimination From Peroxyls," Fast Excitation

Processes Conference, Tokyo, Japan, March 22-25, 1988.

Simic, M. G., "Kinetics and Mechanisms of Physiological Antioxidants,"

Medical, Biochemical, and Chemical Aspects of Free Radicals Conference,

Kyoto, Japan, April 9-13, 1988.

Simic, M. G., "Mechanisms of Oxygen Radical Reactions in Biosystems

FASEB," Las Vegas, NV, May 1-5, 1988.

Simic, M. G., "Resonance DNA Base Radicals," Free Radical and Radiation

Induced Damage to DNA Conference, Max Planck Institute, Mulheim, Germany,

September 26-30, 1988.

Sparrow, Julian H., "High Energy NDT Work at NBS , " D5 Propulsion, NDT

Program Review, Lockheed Missile and Space Co.,, Sunnyvale, CA, April 20,

1988.

Wasson, Oren A., "Neutron Facilities at NBS," Institute of Atomic Energy,

Beijing, People's Republic of China, June 6, 1988.

Wasson, Oren A., "Neutron Standard Cross Section Measurements at NBS,"

Institute of Atomic Energy, Beijing, People's Republic of China, June 7,

1988.

Wasson, Oren A., "Neutron Reaction Studies at NBS," Beijing University,

Beijing, People's Republic of China, June 8, 1988.

Wasson, Oren A., "Neutron Detector Development," Research Institute of

Xian Petroleum Exploration Instrument Complex, Xian, People's Republic of

China, June 14, 1988.

Wasson, Oren, A., "Neutron and Gamma-ray Measurement Methods," Chinese

National Analytical Center, Guangzhou, People's Republic of China,

June 14, 1988.

Wasson, Oren A., "Studies of the Effect of the Properties of NeutronProducing Targets on Neutron Cross Section Measurements, IAEA/International

Nuclear Target Development Society Conference, Gessellschaft f^r Schwerionen

Forschung, Darmstadt, West Germany, September 6, 1988.

Wasson, Oren A. , "Determination of the Uniformity of Uranium Fission

Deposits Using Rutherford Backscatter ing Spectrometry," IAEA/International

Nuclear Target Development Society Conference, Gessellschaft ffr Schwerionen

Forschung, Darmstadt, West Germany, September 9, 1988.

191
PUBLICATIONS

Division 536, Ionizing Radiation

Al-Sheikhly, M. , Hussmann, M. H. , and McLaughlin, W. L. , "Dichromate

Dosimetry: The Effect of Acetic Acid on the Radiolytic Reduction Yield,"

Radiat. Phys . Chem. 32 , 545-551 (1988).

Al-Sheikhly, M. , and Simic, M. G., Inhibition of Autoxidation by Vitamin

E and Bilirubin in Anticarcinogenesis and Radiation Protection , eds . P. Cerutti, 0. F. Nygaard, and M. G. Simic (Plenum Press, New York, 1987),

pp. 47-50.

Al-Sheikhly, M. , and Simic, M. G., Oxygen Uptake in Characterization of

Autoxidation and Antioxidation Processes, in Free Radicals: A Search for

New Methodology . Eds. C. Rice-Evans and B. Halliwell (Richelieu Press,

1988), pp. 481-497.

Behrens, J. W., Ma , Hongchang, and Carlson, A. D., Development of a

3 He/Xe Gas Scintillation Counter for Measuring the Neutron Energy Range

from Thermal to 2 MeV, Transactions of the American Nuclear Society, 56.,

586 (1988).

Berger, M. J., Microdosimetric Event-size Distributions in Small Sites in

Water Irradiated by Protons, Phys. Med. Biol. 33 . 583 (1988).

Berger, M. J., Energy Loss and Range of Electrons, pp . 323 - 345, Nuclear

and Atomic Data for Radiotherapy and Related Radiobiology, International

Atomic Energy Agency, Publication 741, 1987.

Bergtold, D. S., Simic, M. G., Alessio, H. and Cutler, R. G., Urine

Biomarkers for Oxidative DNA Damage, In: Oxygen Radicals in Biology and

Medicine . M. G. Simic, K. A. Taylor, J. F. Ward, C. vonSonntag, eds.

(Plenum Press, New York, 1988).

Brenner, D. J., Zaider, M. , Coyne, J. J., Menzel, H. G., and Prael, R. E. Evaluation of Nonelastic Neutron Cross Sections on Carbon Above 14 MeV,

Nucl. Sci. Eng. 95, 311-315 (1987).

Colie, R., and Hutchinson, J. M. R. , Radon Measurements and Calibration

Standards, Low-Level Measurements and Their Applications to Environmental

Radioactivity . Garcia-Leon, M. and Madurga, G. (eds.), Proceedings of the

First International Summer School, La Rdbida, Huelva Spain, September 28

to October 9, 1987 (World Scientific Pub. Co., Singapore, 1988).

192
Division 536, Publications (cont'd.)

Coyne, J. J., Gerstenberg, H. M. , and Hennen, L. A., Secondary Charged

Particle Spectra and Kerma Calculations, Nuclear and Atomic Data for

Radiotherapy and Related Radiobiology, Proc . of IAEA Advisory Group

Meeting, on Nuclear and Atomic Data for Radiotherapy and Related

Radiobiology, September 16-20, 1985, R.ijswijk, The Netherlands. Panel

Proceedings Series, International Atomic Energy Agency, Vienna, (1987)

pp . 189-204.

Desrosiers, M. F. , Werst, D. W. , and Trifunac , A. D., Olefin Radical

Cations in Pulse Radiolysis of Hydrocarbons, Time-Resolved Fluorescence

Detected Magnetic Resonance, Chem. Phys . Lett. 133 . 201 (1987).

Desrosiers, M. F. , and Simic, M. G., Post- Irradiation Dosimetry of Meat

by Electron Spin Resonance Spectroscopy of Bones, J. Agr. Food Chem., 36 . 601-603 (1988).

Dick, C. E., and Lumbroso, P., X-Ray Attenuation Properties of Radiographic

Contrast Media, Medical Physics L4, 752 (1987).

Domen, S. R. , Convective Velocity Effects on a Thermistor in Water, J.

Res. Nat. Bur Stand. 93, Sept/Oct. (1988).

Eisenhauer, C. M. , Schwartz, R. B., and McCall, R. C., Effect of Air

Scatter on Calibration of Instruments for Detecting Neutrons, Radiation

Protection Dosimetry .19, 2, 77-84, (1987).

Eisenhower, E. H., The National Quality Assurance Program for Personnel

Radiation Dosimetry: A Case History, Proceedings of the Workshop and

Symposium of the National Conference of Standard Laboratories,

Washington, DC, August 15-18, 1988 (1988).

Eisenhower, E. H. , Measurement Quality Assurance, Proceedings of the 25th

Hanford Life Sciences Symposium, Special Issue, Health Physics 55 . No. 2,

207 (August 1988)

.

Farahani, M. , and McLaughlin, W. L. , Radiochromic Dye Dosimeter Solutions

as Reference Measurements Systems, Radiat . Phys. and Chem. 32 , (1988).

Farahani, M. , and McLaughlin, W. L. , Radiation- Induced Cross Links Between

Thymine and 2-deoxyribose , Radiat. Phys. Chem. 32, (1988).

Farahani, M. , and Simic, M. G., Hydroxyl Radical Induced Crosslinking

Between Phenylalanine and 2-Deoxyribose , Biochem. 27 . 4695-4698 (1988).

Ghose , A. M., Bradley, D. A., and Hubbell, J. H., Radiation Field from a Rectangular Plaque Source: Critique of Some Engineering Approximations,

Appl . Radiat. Isot. 39, 421-427 (1988).

193
Division 536, Publications (cont'd.)

Goodman, L. J., Correction to 'Calorimetric Measurement of the Carbon

Kerma Factor for 14.6-MeV Neutrons' by J. C. McDonald, Radiat. Res. 113 . 396-397 (1988).

Goodman, L. J., A Soft-Tissue Substitute Liquid, Health Physics 54

349-

350 (1988).

Grau Malonda, A., and Coursey, B. M., Standardization of Isomeric-Transition

Radionuclides by Liquid Scintillation Efficiency Tracing with Hydrogen-3:

Application to Technetium- 99m , Appl. Radiat. Isot. 18, 695 (1987).

Hruszkewycz, A. M. , and Bergtold, D. S.; Oxygen Radicals, Lipid Peroxidation and DNA Damage in Mitochondria, In: Oxygen Radicals in Biology

and Medicine . M. G. Simic, K. A. Taylor, J. F. Ward, C. vonSonntag, eds

(Plenum Press, New York, 1988).

Hruszkewycz, A. M. , and Bergtold, D. S.; Induction of Mitochondrial DNA

Damage During Mitochondrial Lipid Peroxidation, FASEB J. 2, 7494 (1988).

Humphreys, J. C., Farrar, H., IV, and Fairand, B. P., ASTM Dosimetry

Activities: A Progress Report, Radiat. Phys . Chem. 31 . 409-412 (1988).

Hutchinson, J. M. R. , and Bright, S. J., The NBS Large-Area Alpha- Particle

Counting System, J. Res. NBS 92., 5, 311-324 (1987).

Hutchinson, J. M. Robin, Alpha-Particle Calibrations, NBS Special Publication

250-5, (July 1987)

Hutchinson, J. M. R., Inn, K. G. W. , and Bright, S. J., Low-Level

Radioactivity Standards at the National Bureau of Standards, Proc . of

1st. Int , Summer School on Low-Level Radioactivity Measurements . Dept, of

Atomic and Nucl. Phys., University of Seville, Spain (World Scientific,

1987) pp. 56-79.

Inn, K. G. W., The National Bureau of Standards Fresh Water Lake Sediment

Environmental -Level Radioactivity Standard Reference Material, Journal of

Radioanalytical and Nuclear Chemistry VI 1

5

. 1, 91-112 (1987).

Inn, K. G. W. , Raman, S., Coursey, B. M. , Fassett, J. D., and Walker, R.

L. , Development of the NBS 10 Be/9 Be Isotopic Standard Reference Material,

Nucl. Inst, and Meth. in Phys. Res. B29 . 27-31 (1987).

194
Division 536, Publications (cont'd.)

Inn, K. G. W. , Checklist for Radioanalytical Quality Assurance, Proceedings

of a Symposium held at the 1987 Southwest Regional Meeting of the American

Chemical Society in honor of Dr. Paul K. Kuroda, Little Rock, Arkansas,

December 2-4, 1987, Essays in Nuclear Geo- and Cosmochemistrv . edited by

M. W. Rowe (Burgess International Group, Inc., Bellwether Press Div.

,

Edina, MN, 1988), Chapter 32, pp . 515-533.

Inokuti, M. , and Berger, M. J., Survey and Compilation of Stopping Power

Data Conducted the International Commission on Radiation Units and

Measurements, Nucl. Instr. Meth. B27

.

249 (1987).

Jovanovic, S. V., and Simic, M. G., Redox Properties of Oxy and Antioxidant

Radicals, in Oxygen Radicals in Biology and Medicine. Eds. M. G. Simic,

K. A. Taylor, J. F. Ward (Plenum Press, New York, 1988).

Karam, L. R. , and Simic, M. G., Ortho-Tyrosine as a Marker in Post

Irradiation Dosimetry of Chicken, Health Impact, Identification, and

Dosimetry of Irradiated Foods, Report of a WHO Working Group on Health

Impact and Control Methods of Irradiated Foods, Neuherberg/Munich , 17-21

November, 1986; K. W. Bogl, D. R. Regulla and M. J. Suess , Eds., pp . 297-

304 (June 1988).

Karam, L. R. , Dizdaroglu, M. , and Simic, M. G., Intramolecular H Atom

Abstraction from the Sugar Moiety by Thymine Radicals in Oligo- and

Polydeoxynucleotides , Radiation Research (1988).

Karam, L. R., and Simic, M. G., Mechanisms of Free Radical Chemistry and

Biochemistry of Benzene, Proceedings of the International Symposium on Benzene Metabolism, Toxicity and Carcinogenesis, Environmental Health

Perspectives, 1988.

Karam, L. R., and Simic, M. G., Detection of Irradiated Meats: a Use of

Hydroxyl Radical Biomarkers, Analy. Chem. 6j3, No. 19 (1988).

Lamaze, G. P., and Grundl , J. A., NBS Measurement Services: Activation

Foil Irradiation with Californium Fission Sources, SP250-13 (1988).

Lamaze, G. P. and Grundl, J. A., NBS Measurement Services: Activation

Foil Irradiation by Reactor Cavity Fission Sources, SP250-14 (1988).

Lamaze, G. P., Gilliam, D. M. , Williams, A. P., Prompt Gamma as a Fluence

Rate Monitor in Neutron Beam Experiments, Journal of Radioanalytical and

Nuclear Chemistry 123 . No. 2, 551 (1988).

Lamaze, G. P., Schima, F. J., Eisenhauer, C. M. , and Spiegel, V., Spectrumaveraged Cross-section Measurement of 1 0

3

Rh(n , n'

)

1 0 3

m

Rh in the 252 Cf

Fission Neutron Spectrum, Nucl. Sci. Engr . 100 . 43 (1988).

195
Division 536, Publications (cont'd.)

Lett, J. T., Keng, P. C., and Bergtold, D. S., Effects of Heavy Ions on Rabbit Tissues: Induction of DNA Strand Breaks in Retinal Photoreceptor

Cells by High Doses of Radiation, Radiation and Environmental Biophysics

26, 23-36 (1987).

Loevinger, R., The Role Of The Water Calorimeter In High-Energy Medical

Radiation Dosimetry, Proceedings of the June 1988 Workshop on Water

Calorimetry (National Research Council, Ottawa, Canada, 1988).

Mann, W. B., Rytz , A., and Spernol, A., Radioactivity Measurements,

Principles and Practice, Special Issue of IJARI Part A: Applied Radiation

and Isotopes .39, No. 8 (1988).

McGarry, E. D., and Boswell, E., Neutron Source Strength Calibrations,

NBS SP-250- 18 (1988) .

McLaughlin, W. L. , Dosimetry for Industrial Radiation, Trans. Amer. Nucl.

Soc. 55, 160-163 (1987).

McLaughlin, W. L. , Comprehensive Dosimetry for Food Irradiation,

Proceedings of Working Group on Health Impact Identification and Dosimetry

of Irradiated Foods held at GSF, Neuherberg, FRG , November 1986. Institut

fur Strahlenhygiene Report No. 125 . Copenhagen (1988), pp . 384-399.

McLaughlin, W. L. , Ba, Wei-Zhen, and Chappas , W. J., Cellulose Diacetate

Film Dosimeters, Radiat. Phys . Chem. 31 . 481-490 (1988).

McLaughlin, W. L. , Humphreys, J. C., Hocken, D. G., and Chappas, W. J.,

Radiochromic Dosimetry for Validation and Commissioning of Industrial

Radiation Processes, Radiat. Phys. Chem. 3.1. 505-514 (1988).

McLaughlin, W. L. , Khan, H. M. , Warasawas , W. , Al-Sheikhly, M., and

Radak, B. B., Optical Waveguide Dosimetry for Gamma Radiation in the Dose

Range 10" 1 to 3 x 10 4 Gy, Radiat. Phys. Chem. 32 (1988).

Nath, R. , Loevinger, R. , et. al., Specification of Brachytherapy Source

Strength, AAPM Report No. 21, The American Institute of Physics, NY,

1987.

Radak, B. B., McLaughlin, W. L. , Simic, M. G. and Warasawas, W., Dosimetry

of Steady-State Gamma Rays or Pulsed X Rays Using Liquid-Core Optical

Waveguides, Radiat. Phys. Chem. 30, 243-251 (1987).

Radak, B. B., Lj . Secerov, B., McLaughlin, W. L. and Simic, M. G., Liquid

Optical Waveguide Dosimetry in Continuous and Pulsed Radiation Fields,

Proceedings of 6th Symp . on Radiation Chemistry, 711-717 (1988).

196
Division 536, Publications (cont'd.)

Radak, B. B., McLaughlin, W. L. and Simic, M. G., Optical Waveguides with

Liquid Core in Spectrophotometry, J. Serb. Chem. Soc . 52., 405-410 (1987).

Saloman, E. B., Hubbell, J. H. , and Berger, M. J., NIST Database of

Photon Absorption Cross Sections from 10 eV to 100 keV, Proceedings of

SPIE Conference, Vol. 911, p. 100 (1988).

Saloman, E. B., Hubbell, J. H., and Scofield, J. H., X-ray Attenuation

Cross Sections for Energies 100 eV to 100 keV and Elements Z = 1 to Z =

92, Atomic Data and Nuclear Data Tables .38, 1-197 (1988).

Saylor, M. C., Tamargo , T. T., McLaughlin, W. L. , Khan, H. H., Lewis,

D. F. , and Schenfele, R. D., A Thin Film Recording Medium for Use in Food

Irradiation, Radiat. Phys . Chem. 3_1, 529-536 (1988).

Schima, F. J., Williamson, T. G., Ayers, T. A., Hamersten, W. L. , and

Lamaze, G. P., Measurement of the 93 Nb(n,n') Fission Spectrum Cross

Section, Proceedings of the ASTM-EURATUM Symposium on Reactor Dosimetry,

Jackson, WY, ASTM STP-1001 (1988).

Schima, F. J., Williams, J. G., Cogburn, C. 0. Hodgson, L. M. , Apple,

S. C., McGarry, E. D., Lamaze, G. P., Rogers, J. W. , Gehrke , R. , Baker,

J. D. , and Wheeler, F. J., Measurements of Fission Spectrum averaged

Cross Sections for the 93m Nb Reaction, Proceedings of the ASTM-EURATUM

Symposium on Reactor Dosimetry, Jackson, WY, ASTM STP-1001 (1988).

Schrack, R. A., NBS Work on Neutron Resonance Radiography, Report of a Workshop on Neutron Resonance Radiography held at Los Alamos National

Lab., Los Alamos, NM, July 27-29, 1987, LA-11393-C (July 1988).

Seltzer, S. M. , Calculated Response of a 5.5 x 5.5cm High-purity Ge

Detector to Gamma Rays with Energies up to 20 MeV, NBSIR 87-3348 (1987).

Simic, M. G., Karam, L. R. , and Desrosiers, M. F., Peptide Irradiation

Products and Crosslinking Mechanisms, Proceedings of the 8th International

Congress on Radiation Research, Radiation Research IX. eds. Taylor and

Frances, 140-145 (1987).

Simic, M. G., and Taylor, K. A., Free Radical Mechanisms of Meat Oxidation,

in Flavor Quality of Fresh Meat: Warmed-Over Flavor , eds. A. J. St-Angelo

and M. E. Bailey, (Academic Press, 1987), p. 69-117.

Simic, M. G., Hunter, E. P. L. , and Jovanovic, S. V., Electron vs. H-atom

Transfer in Chemical Repair, in Anticarcinogenesis and Radiation Protection , eds. P. Cerutti, 0. F. Nygaard, and M. G. Simic (Plenum Press, New York,

1987), pp. 17-24.

197
Division 536, Publications (cont'd.)

Soares, C. G., Bright, E. L. , and Ehrlich, M. , Difficulties Encountered

with Some High-Atomic Number Personnel Dosimeters Irradiated On-Phantom

with Low-Energy Photons, Health Physics 54., 431-444 (1988).

Williamson, T. G., and Lamaze, G. P., Niobium as a Neutron Dosimeter,

Transactions of the American Nuclear Society 55 . 553 (1987).
PUBLICATIONS IN PREPARATION

Division 536, Ionizing Radiation

Al-Sheikhly, M. , and Simic, M. G., Chain- Propagation Length of Linoleic Acid

Peroxidation in Aqueous Monomeric and Micellar Systems, J. Phys . Chem.

(submitted)

.

Ballaux, C., Coursey, B. M. , and Hoppes, D. D., 109 Pd and 109 Cd Activity

Standardization and Decay Data, to be published in Appl. Radiat. Isot.

(in press)

.

Barrett, J. H., Glover, K. M. , McLaughlin, W. L. , Sharpe, P. H. G., Watts,

M. J., and Whittaker, B., Intercomparison Studies of Gamma-Ray Absorbed

Dose Using Radiochromic Dye Films and Red 4034 Perspex, to be published

in Appl. Radiat. Isotopes.

Berger, M. J., Multiple Scattering Angular Deflections and Energy-Loss

Straggling in Electron Transport Calculations, Monte Carlo Calculations

of Electron and Photon Transport , eds , T. A. Jenkins, W. R. Nelson and

A. Rindi, Plenum, NY (in press).

Behrens, J. W., Wasson, 0. A., Carlson, A. D., and Ma , Hongchang, Development

of a

3 He/Xe Gas Scintillation Counter to Measure the 3 He(n,p)T Cross

Section in the Intermediate Energy Range, Proc . of the International

Conference on Nuclear Data for Science and Technology, Mito, Japan, May

30-June 3, 1988 (in press).

Behrens, J. W. , Ma , Hongchang, Wasson, 0. A., Westerfeldt, C., and Lewis,

H., Development of a

3 He Gas Scintillation Counter for Measuring the

Intermediate Neutron Energy Range from 1 keV to 3 MeV , to be submitted to

Nucl. Instrum. Methods.

Berger, M. J., Electron Stopping Powers for Transport Calculations,

Monte Carlo Calculations of Electron and Photon Transport , eds, T. A.

Jenkins, W. R. Nelson and A. Rindi, Plenum, NY (in press).

Berger, M. J., Cross Sections for Bremsstrahlung Production and ElectronImpact Ionization, Monte Carlo Calculations of Electron and Photon Transport , eds, T.A. Jenkins, W.R. Nelson and A. Rindi, Plenum, NY (in press).

Bergtold, D. S., Keng, P. C., and Lett, J. T., The Loss of Structural

Integrity in Rabbit Sensory Cell DNA During Aging (submitted to Proc.

Natl. Acad. Sci. U.S.A.).

Bergtold, D. S., and Simic, M. G., Background Levels of DNA Damage, Free

Radical Research Communications (in press).

199
Division 536, Publications in Preparation (cont'd.)

Bergtold, D. S., Alessio, H., and Cutler, R. G., Oxyradical Damage to

DNA: Correlation with Lifespan and Age of Different Mammalian Species,

The Gerontologist (in press).

Bergtold, D. S., DNA Damage Measurements and Aging, The Gerontologist (in

press)

Bigbee, P. D., Sarin, P. S., Humphreys, J. C., Eubanks, W. G., Sun, D.,

Hocken, D. G., Thorton, A., Adams, D. E., and Simic, M. G., Inactivation

of Human Immunodeficiency Virus (HIV) by Ionizing Radiation in Body

Fluids and Forensic Evidence, to be published in Journal of Forensic

Sciences

Carlson, A. D., Wasson, 0. A., Lisowski, P. W. , Ullmann, J. L. , and

Hill, N. W. , A Study of the 235 U(n,f) Cross Section in the 3 to 30 MeV

Energy Region, Proc . of the International Conference on Nuclear Data for

Science and Technology, Mito, Japan, May 30-June 3, 1988 (in press).

Caswell, R. S., Coyne, J. J., Gerstenberg, H. M. , and Axton, E. J., Basic

Data Neccessary for Neutron Dosimetry. Proc. of the 6th Symp . on Neutron

Dosimetry, Oct. 12-16, 1987 (to appear in a special issue of the Radiat.

Protection Dosimetry)

Coursey, B. M. , Lucas, L. L. , Grau Malonda, A., and Garcia-Torano , E., The

Standardization of Plutonium- 241 and Nickel-63 (in WERB review).

Coursey, B. M., Hirshfeld, A. T., Hoppes, D., Judge, S. M., Woods, D. H.,

Woods, M. J., Funk, E., and Tuck, A. G., Standardization and Decay Scheme

of 201 T1, to be published in Appl. Radiat. Isot. (in press).

Desrosiers, M. F. , Simic, M. G., Eichrailler, F. C., Johnston, A. D., and

Bowen, R. L. , Generation of Radicals in Dentin and Enamel by Mechanical

Instrumentation of Teeth (submitted to Nature)

Desrosiers, M. F. , Gamma- Irradiated Seafoods: Identification and Dosimetry

by Electron Paramagnetic Resonance Spectroscopy, to be published Sept/Oct,

1988 in J. Agric. Food Chem.

Desrosiers, M. F. , Simic, M. G., Eichmiller, F. C., Johnston, A. D., and

Bowen, R. L. , Mechanically- Induced Generation of Radicals in Teeth, Nature,

submitted

Dobrilovic, Lj .

,

Simovic, M., Bek-Uzarov, Dj .

,

Hutchinson, J. M. R. , and

Mann, W. B., Properties of Monomolecular Films in Relation to Their Use

for Standard Sources of Radioactivity, IJARI (in press).

Domen, S. R. , Letter: Further Comments on Convection Currents in a Water

Calorimeter. Phys . Med. Biol, (in press).

200
Division 536, Publications in Preparation (cont'd.)

Domen, S. R. , Convective Velocity Effects on a Thermistor in Water, J.

Res. Nat. Bur. Stand, (in press).

Domen, S. R. , The Role of Water Purity, Convection, and Heat Conduction in

a New Calorimeter Design, Proc . NRC Workshop on Water Calorimetry, Ottawa,

Canada, June 6-7, 1988 (in press).

Duvall, K. C., Seltzer, S. M. , Soares, C. G., and Rust, B. W. , Dosimetry

of a Nearly Monoenergetic 6-7 MeV Photon Source by Nal (TI) Scintillation

Spectrometry, Nucl. Instrum. Methods (in press).

Duvall, K, C., Wasson, 0. A., and Ma, Hongchang, 2.5 MeV Neutron Source

for Fission Cross Section Measurement, Proc. of the International Conference

on Nuclear Data for Science and Technology, Mito, Japan, May 30-June 3,

1988 ( in press)

.

Duvall, K. C., and Johnson, R. G., Monte Carlo Calculated Response of the

Dual Thin Scintillation Detector in the Sum Coincidence Mode, Proc. of

the International Conference on Nuclear Data for Science and Technology,

Mito, Japan, May 30-June 3, 1988 (in press).

Duvall, K. C., Seltzer, S. M. , Soares, C. G., and Rust, B. W. , Dosimetry

of Nearly Monoenergetic 6-7 MeV Photon Source by Nal (Ti) Scintillation

Spectrometry, Nucl. Instrum. Methods (in press).

Eisenhauer, C. M. , and Hunt, J. B., Anisotropic Neutron Emission from a 252 Cf Source, Rad. Prot. Dosim. (in press).

Farahani , M. , Liang, J. H., and McLaughlin, W. L. , Sensitive Radiochromic

Dosimeter Solutions for Medical Applications, to be published in Appl.

Radiat. Isotopes.

Gerstenberg, H. M. , Caswell, R. S., and Coyne, J. J., Initial Spectra of

Neutron- Induced Secondary Charged Particles, Proc. of the 6th Symp . on Neutron Dosimetry, Oct. 12-16, 1987 (to appear in a special issue of the

Radiat. Protection Dosimetry).

Gilliam, D. M. , Hocken, D. G., Humphreys, J. C., and Lamaze, G. P.,

Neutron Sensitivity of LiF Chip Gamma Dosimeters at Megagray Doses,

Proceedings of 6th ASTM-EURATOM Symposium on Reactor Dosimetry, Jackson

Hole, WY, May 31-June 5, 1987 (in press).

201
Division 536, Publications in Preparation (cont'd.)

Grau Malonda, A., and Coursey, B. M. , Calculation of Beta-particle Counting

Efficiency for Liquid Scintillation Systems with Three Phototubes, to be

published in Appl. Radiat. Isot. (in press).

Grundl, J. A., Derivation of Neutron Exposure Parameters from Threshold

Detectors Measurements, Proceedings of 6th ASTM-EURATOM Symposium on Reactor Dosimetry, Jackson Hole, WY, May 31-June 5, 1987 (in press).

Heaton, II, H. T., Computer Program for Instrument Calibration at StateSector Secondary Level Laboratories, Proceedings of the 22nd HPS Midyear

Topical Meeting on Instrumentation (in press for 1988).

Hunter, E. P. L. Desrosiers, M. F., and Simic, M. G., Inhibition of Tyrosine

Phenoxy Radical Dimerization by Antioxidants and Superoxide Radical, Free

Radical Biol. Med. (in press).

Hunter, E. P. L. , Desrosiers, M. F. , and Simic, M. G., The Effect of Oxygen,

Antioxidants, and Superoxide Radical on Tyrosine Phenoxyl Radical

Dimerization (accepted by J. Free Rad. Biol. Med.).

Inn, K. G. W. , Liggett, W. S., Jr., Volchok, H. L. (Deceased May 1987),

Feiner, M. S., Mclnroy, J. F. , Popplewell, D. S., Percival, D. R. , Wessman,

R. A., Bowen, V. T., Livingston, H. D., Kathren, R. L. , and Kawamura, H.,

Interlaboratory Comparison of Actinides in Human Tissue 2 3 9 Pu +

2 A

0

Pu (to

be submitted to Journal of Radioanalytical and Nuclear Chemistry)

Inn, K. G. W. , National Bureau of Standards Natural-Matrix Environmental

level Radioactivity Standard Reference Materials (submitted to Int. J.

Radioanalytical and Nucl. Chem.).

Inn, K. G. W., State of the Art Bioassay Procedures to Detect and Quantify

Previous Exposures to Radiation, ORAU Subcommittee report to the National

Cancer Institute and the U. S. Congress. Released August 1987 (ORAU284).

Johnson, R. G., Carlson, A. D., Wasson, 0. A., Duvall, K. C., Behrens,

J. W. , Meier, M. M. , Patrick, B. D., and Dias, M. S., Measurements of the

235 U(n,f) Standard Cross Section at the National Bureau of Standards,

Proc. of the International Conference on Nuclear Data for Science and

Technology, Mito, Japan, May 30-June 3, 1988 (in press).

Jovanovic, J. V., and Simic, M. G., The DNA-guanyl Radical: A Pulse

Radiolysis Study, Biophys . Biochem. Act., submitted.

Karam, L. R., and Simic, M. G., Ortho-Tyrosine as Marker in Post Irradiation

Dosimetry (PID) of Chicken (to be published in J. Agr. Food Chem.).

202
Division 536, Publications in Preparation (cont'd.)

Karam, L. R. , and Siraic, M. G., Mechanisms of Free Radical Chemistry and

Biochemistry of Benzene, Environmental Health Perspectives (in press).

Karam L. R. , and Simic, M. G., Detection of Irradiated Meats: A Use of

Hydroxyl Radical Biomarkers, Analytical Chemistry (in press).

Karam, L. R. , and Simic, M. G., Generation of OH Radicals in Muscle Tissue

by Organic Solvents, Submitted to Science.

Lamaze , G. P., Eisenhauer, C. M. , Grundl , J. A., McGarry, E. D., Schima,

F. J., and Spiegel, V., Cross-Section Measurements in the Intermediate - Energy Standard Neutron Field, Proc . of the International Conference on Nuclear Data for Science and Technology, Mito, Japan, May 30-June 3, 1988

( in press)

.

Mattsson, 0., Svensson, H., Wickman, G., Domen, S. R. , Pruitt, J. S., and

Loevinger, R. , Investigation of Dosimetry Interaction Coefficient by

Intercomparison Using a Liquid Ionization Chamber, Acta Radiol. Oncol.

In review.

McGarry, E. D., and Prillinger, G., Comparison of Experimental and Calculated

Neutron Dosimetry for Materials at the Buffalo Reactor, Proc. of the 14th

ASTM-E10 International Symposium on the Effects of Radiation on Materials,

Andover, MA, June 27-29, 1988 (in press).

McLaughlin, W. , Boyd, A. W. , Chadwick, K. H., McDonald, J. C., and Miller,

A., Dosimetry for Radiation Processing (Taylor and Francis, London), to

be published 1989.

Navon, E., Barnea, G., and Dick, C. E., The Intensifying Effect of Metallic

Screens on the Sensitivity of X-Ray Films at 662-keV, submitted for

publication in Journal of Applied Physics.

Prillinger, G., McGarry, E. D., and Hawthorne, R., Neutron Spectra Calculations for Materials Engineering Associates Ex-core Irradiation Experiments

at the Buffalo Reactor, Proc. of the 14th ASTM-E10 International Symposium

on the Effects of Radiation on Materials, Andover, MA, June 27-29, 1988

( in press )

.

Schrack, R. A., Measurement of the 235 U(n,f) Reaction from Thermal to 1 keV, Proc. of the International Conference on Nuclear Data for Science and

Technology, Mito, Japan, May 30-June 3, 1988 (in press).

Seltzer, S. M., Applications of the ETRAN Code to Some Radiation Transport

Problems, Monte Carlo Calculations of Electron and Photon Transport , eds

.

T. A. Jenkins, W. R. Nelson and A. Rindi , Plenum, NY (in press).

203

J
Division 536, Publications in Preparation (cont'd.)

Seltzer, S. M., An Overview of ETRAN Monte Carlo Methods for Coupled

Electron/Photon Transport Calculations, Monte Carlo Calculations of

Electron and Photon Transport, eds. T. A. Jenkins, W. R. Nelson and A.

Rindi , Plenum, NY (in press).

Seltzer, S. M. , Cross Sections for Bremsstrahlung Production and for

Electron Impact Ionization, Monte Carlo Calculations of Electron and

Photon Transport , eds. T. A. Jenkins, W. R. Nelson and A. Rindi, Plenum,

NY (in press )

Seltzer, S. M. , Bremsstrahlung Production by Electrons: Cross Sections

and Electron-photon Transport Calculations, Proc . of the Conference on High Energy Radiation Background in Space, Sanibel Island, FL, Nov. 3-5,

1987, AIP Conf. Proceedings (in press).

Simic, M. G., Al-Sheikhly, M. , and Jovanovic, S. V., Inhibition of Free

Radical Processes by Antioxidants - -Tryptophan and 5 -Hydroxy-Tryptophan

,

Eds. H. R. Mueller, J. C. Somogyi, Karger Press (in press).

Simic, M. G., Mechanisms of Inhibition of Free Radical Processes in

Mutagenesis and Carcinogenesis, Mutation Res. (in press).

Williams, J., Cogburn, C., Hodgson, L. , Apple, S., McGarry, E. D., Lamaze

,

G., Gilliam, D., Grundl, J., Coursey, F. Schima, Rogers, J. W. , Gherke , R.,

Baker, J. D., and Wheeler, F. J., Measurement of Fission Spectrum Averaged

Cross Sections for the 9

3

Nb (n , n'

)

9 3

Nb Reaction, ASTM Special Tech. Pub.

1001 (in press )

Williamson, T. G., and Lamaze, G. P., Photon Excitation of 93ra Nb, Proc.

of 7th International Conference on Radiation Shielding, Bournemouth,

England, September 1988 (in press).

Williamson, T. G., Lamaze, G. P., Gilliam, D. M. , and Eisenhauer, C. M.

,

Iron and Cadmium Capture Gamma Ray Photofission Measurements, ANS Topical

Conference on Theory and Practices in Radiation Protection and Shielding,

Knoxville, TN , April 22-24, 1987 (in press).

Williamson, T. G., Lamaze, G. P., and Gilliam, D. M. , Calibration of a Neutron Driven Gamma Ray Source, ASTM Special Tech. Pub. 1001 (in press).

Williamson, T. G., Ayers, T. A., Hammerson, W. L. , and Lamaze, G. P.,

93 Nb(n,n') Cross Section Measurement in a Fission Spectrum, ASTM Special

Tech. Pub. 1001 (in press).

Yin, Lo I, Trombka, J. I., and Seltzer, S. M. , Pattern Recognition Approach

in XRF Analysis, Nucl. Instrum. Methods (submitted).

204
Division 536, Publications in Preparation (cont'd.)

Yin, Lo , Trombka , J. I., and Seltzer, S.M., Possible Use of Pattern Recognitition for the Analysis of Mars-Rover XRF Spectra, submitted to J . of

Geophys. Res.

205
TECHNICAL AND PROFESSIONAL COMMITTEE PARTICIPATION AND LEADERSHIP

Division 536, Ionizing Radiation

James W. Behrens

Chairman, Nuclear Data Committee, Isotopes and Radiation Division,

American Nuclear Society.

Chairman, Transuranic Task Force, Isotopes and Radiation Division,

American Nuclear Society.

Member, Program Committee for the American Nuclear Society/European

Nuclear Society Meeting to be held in Washington, D.C. (Nov 1988).

Chairman, Organizing Committee for conference entitled "Fifty Years

with Nuclear Fission" to be held at the NIST (April, 1989).

Member, Cross Section Evaluation Working Group Subcommittee on Nuclear Data Review.

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 on Dosimetry.

Member, NCRP Committee #55 (inactive) on Experimental Verification

of Internal Dosimetry.

Jacqueline M. Calhoun

EEO Counselor, NIST, two-year re-appointment, January 7, 1987 through

January 7, 1989.

Member, Advisory Panel on Radiopharmaceuticals, U.S. Pharmacopoeia.

Allan D. Carlson

Chairman, Standards Subcommittee, Cross Section Evaluation Working

Group (CSEWG)

206
Division 536, Technical and Professional Committee Participation and

Leadership (cont'd.)

Allan D. Carlson (cont'd.)

Member, Evaluation Committee of CSEWG.

Member, Data Status and Requests Subcommittee of CSEWG.

Chairman, Program Committee for conference entitled "Fifty Years

with Nuclear Fission" to be held at the NIST (April, 1989).

Randall S. Caswell

Chairman, Science Panel, Committee on Interagency Radiation Research

and Policy Coordination (CIRRPC) , Office of Science and Technology

Policy.

Alternate Member, CIRRPC.

Member, Consultative Committee for Ionizing Radiations (CCEMRI),

Conference Generale des Poids et Mesures , Paris, France.

Chairman, Section on Neutron Measurements (Section III), CCEMRI.

Member, National Council on Radiation Protection and Measurements

(NCRP)

.

Member, Commission of the European Communities (CEC) Program Committee,

Sixth Symposium on Neutron Dosimetry.

Member, CEC Program Committee, Seminar on Implementation of DoseEquivalent Operational Quantities into Radiation Protection Practice.

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 Material Equivalent and Tissue

Substitutes

.

Sponsor, ICRU Report Committee on Absorbed Dose Standards for Photon

Irradiation and Their Dissemination.

Sponsor, ICRU Report Committee on Clinical Dosimetry for Neutrons

(Physics )

.

207
Division 536, Technical and Professional Committee Participation and

Leadership (cont'd.)

Ronald Colie

Member, Radon Working Group, Interagency Committee on Indoor Air

Quality

Chairman, International Standards Organization, Working Group on Measurement Uncertainties.

Bert M. Coursey

Member, International Committee for Radionuclide Metrology (ICRM)

Life Sciences Working Group.

Member, ANSI Committee N42.02 on Nuclear Instruments, Procedural

Standards for Calibration of Detectors for Radioactive Measurements.

Member, Delegate to Section I, Consultative Committee for Ionizing

Radiations (CCEMRI), Conference G6n6rale des Poids et Mesures,

Paris, France.

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 Agency Advisory Group on Nuclear and

Atomic Data for Radiotherapy and Radiobiology.

Charles E. Dick

Member, Technical Organizing Committee, Industrial Applications,

International Conference on the Applications in Research and Industry.

Member, Editorial Board, Industrial Metrology.

Charles M. Eisenhauer

Member, CIRRPC Science Panel; Chairman, Subpanel on Predisaster

Planning

208
Division 536, Technical and Professional Committee Participation and

Leadership (cont'd.)

Charles M. Eisenhauer (cont'd.)

Member, Working Group 2, Reference Radiations Subcommittee 2, Technical

Committee 5, International Standards Organization.

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, NAS-NRC Advisory Committee on the Radiation Effects Research

Foundation; Advisory Dosimetry Subcommittee.

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.

Alternate Representative, 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.

Member, ASTM Subcommittee E10.04 on Radiation Protection Methodology.

Chairman, ASTM Task Group E10.07.05 on Performance of Calibration

Laboratories for Radiation Dosimetry in Industrial Testing and

Processing

.

Member, ASTM Committee E10 on Nuclear Technology and Applications.

Member, CIRRPC Science Subpanel on Scientific Basis for Radiation

Protection Standards.

Member, Operations Group for the Accreditation of Instrument Calibratior

Laboratories, Health Physics Society.

Member, CIRRPC Ad Hoc Working Group on Transuranics in the Environment

(Identification of issues related to guidance).

209
Division 536, Technical and Professional Committee Participation and

Leadership (cont'd.)

James A. Grundl

Member, NCRP Task Group SC-63 on Public Knowledge About Radiation

Emergencies

Member, ASTM Subcommittee E10.05 on Nuclear Radiation Metrology.

H. Thompson Heaton, II

Alternate Representative, ANSI N43 , Equipment for Non-Medical Radiation

Applications

Member, ANSI N43-3, 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

Secretary, International Committee for Radionuclide Metrology (ICRM).

Member, ICRM Beta- and Gamma-Ray Spectrometry Working Group.

Member, U.S. Council for Energy Awareness (USCEA)-NBS Standards

Program Committee.

Member, International Committee of Weights and Measures (CIPM)

,

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

Chairman, General Radiation Protection Section, Health Physics

Society Standards Committee.

Organizer and overseer, Task Groups; ANSI Standard N-319 on Personnel

Neutron Dosimeters; and ASTM-E-10.04 PlanCo 56 on Radiation Protection

Survey Documentation, PlanCo 57 on Airborne Radioactive Particulates,

and PlanCo 58 on Low-level Radwaste.

Chairman, American Nuclear Society (ANS) Radiation Protection and

Shielding Division, ANS-6 Ad Hoc Committee on SI Units.

210
Division 536, Technical and Professional Committee Participation and

Leadership (cont'd.)

John H. Hubbell (cont'd.)

Members, ANS Isotopes and Radiation Division Industrial Radiation

Measurement Applications Committee; Organizer and Chairman of

sponsored session: "Atomic and Radiation Data and Applications",

for November 15-19, 1987 ANS Meeting.

Member, ANS Isotopes and Radiation Division Industrial Radiation

Measurement Applications Committee.

Member, ANS Technical Program Committee for Sponsored Topical Meeting,

"Industrial Radiation and Radioisotope Measurement Applications",

September 5-8, 1988. Also chaired a session.

Executive Councilor, International Radiation Physics Society; Member

Nominating Committee for 1988 elections. Also member, International

Advisory Board for the 4th International Symposium on Radiation

Physics, Sao Paulo, Brazil, October 3-7, 1988. Also chaired a session.

Secretary, X-Ray Absorption Task Group, International Union of

Crystallography Commission on Crystallographic Apparatus.

Member Cross Section Evaluation Working Group, (CSEWG) Subcommittee

on Shielding.

Jimmy C. Humphreys

Secretary, ASTM E10.07 Subcommittee, Ionizing Radiation Dosimetry and

Radiation Effects on Material and Devices.

Member, ASTM Subcommittee E10.01 Dosimetry for Radiation Processing.

Member, ASTM Subcommittee FI. 11, Hardness Assurance of Electronics.

Member, AAMI (Association for the Advancement of Medical

Instrumentation) subcommittee task groups on dosimetry of gamma and

electron beam sterilization of medical products and devices.

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.

211
Division 536, Technical and Professional Committee Participation and

Leadership (cont'd.)

J. M. Robin Hutchinson (cont'd.)

Secretary, ANSI Subcommittee N42 . 2 on Procedural Standards for

Calibration of Detectors for Radioactivity Measurements.

Kenneth G. W. Inn

Member, ANSI N42.02, Quality Assurance for Radioassay of Environmental

Samples

Member, ASTM Committee C26.05.01, Methods of Test, Test Methods,

Environmental Methods.

Member, ASTM Committee D19, Water, radioactivity Test Methods.

George P. Lamaze

Secretary, ASTM Committee E10, Nuclear Radiation Metrology.

Vice-Chairman, ASTM Subcommittee E10.05, Nuclear Radiation Metrology

Chairman, Membership Subcommittee, ASTM Committee E10, Nuclear

Technology and Applications.

Secretary, Planning Committees for the 6th and 7th ASTM-EURATOM

Symposia on Reactor Dosimetry.

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, Accredited

Dosimetry Calibration Laboratories.

Wilfrid B. Mann

Consultant, ICRU.

212
Division 536, Technical and Professional Committee Participation and

Leadership (cont'd.)

Wilfrid B. Mann (cont'd.)

Member, ANSI-INMM Working Group INMM 8.04 Calibration Technique for

the Calorimetric Assaying of Plutonium-Bearing Solids Applied to

Nuclear Materials Control.

Honorary Council Member, NCRP.

Chairman, NCRP Committee 18A, Standards and Measurement of Radioactivity

for Radiological Use.

Life Member, ICRM.

Emmert D. McGarry

Member, ASTM Committee E10; Subcommittee E10.05, Nuclear Radiation

Metrology

.

Chairman, Awards Committee of ASTM Subcommittee E10.05.

Member, Planning Committee for the 8th ASTM-EURATOM Symposium on Reactor Dosimetry.

William L. McLaughlin

Technical Advisor Council of Europe Parliamentary Assembly, Work

Group on Aerospace Physiology, Medicine, and Radiation Measurement.

Technical Advisor, Council of Europe Parliamentary assembly, Work

Group on Space Biophysics.

Member, R & D Associates Committee on Irradiated Food Products.

Member, International Atomic Energy Agency (IAEA), Advisory Group on High Dose Measurement and Standardization for Radiation Processing.

Member, Association for Advancement of Medical Instrumentation,

Subcommittee on Radiation Sterilization Dosimetry (Working Groups on Gamma Ray Sterilization and Electron Beam Sterilization)

.

Technical Advisor, National Council on Radiation Protection and

Measurement, Scientific Committee 63, Radiation Exposure Control in

a Nuclear Emergency.

Science and Technology Consultant, CIRRPC.

213
Division 536, Technical and Professional Committee Participation and

Leadership (cont'd.)

William L. McLaughlin (cont'd.)

Chairman, Advisory Panel on Electron Beam Dosimetry for Industrial

Radiation Processing, International Atomic Energy Agency.

Member Advisory Panel on Guidelines on Dosimetry for Industrial

Radiation Processing, International Atomic Energy Agency.

Member of Organizing Committee and Chairman for Invited Speakers for

International Workshop on Dosimetry for Radiation Processing, SteAdele, Quebec, Canada.

Member, Organizing and Program Committees, 2nd International Symposium

on ESR Dosimetry and Applications, Munich 1988.

Member ASTM Subcommittee E10.07 on Ionizing Radiation Dosimetry and

Radiation Effects on Materials and Devices.

Member, Ad-Hoc Interdepartmental Committee on Food Irradiation

(Secretariat, Department of Commerce).

Stephen M. Seltzer

Member, Program Advisory Board, Conference on High Energy Radiation

Background in Space, November 3-5, 1987.

Member, ICRU Committee on Stopping Power.

Member, ANS Nuclear Data Committee.

Member, ANS Radiation Effects Committee.

Francis J. Schima

Research Associate Member, IAEA, Coordinated Research Program on Gamma-ray Standards for Detector Efficiency Calibration.

Member, ICRM Working Group on Gamma- and Beta-ray Spectrometry.

Scientific and Technical Consultant, CIRRPC.

Robert B. Schwartz

Member, International Standards Organization (ISO) Technical Committee

85 (Nuclear Energy) , Subcommittee 2 (Radiation Protection) , Working

Group 2 (Reference Radiations). Chairman, Neutron Sub-Group.

214
Division 536, Technical and Professional Committee Participation and

Leadership (cont'd.)

Robert B. Schwartz (cont'd.)

Member, ICRU Report Committee on Practical Determination of Dose

Equivalent

.

Michael G. Simic

Member of CAST (Council of Agricultural Science and Technology)

.

Secretary General of the Oxygen Society.

Member of the Advisory Board Critical Reviews of Sulfhydryl Chemistry.

Christopher G. Soares

Member of Health Physics Scientific Subcommittee Work Group for the

revision of ANSI N13.ll, "Personnel Dosimetry Performance - Criteria

for Testing"

.

Michael P. Unterwerger

Member, ASTM Committee D22 on Sampling and Analysis of Atmospheres.

Oren A. Wasson

Member, Department of Energy Nuclear Data Committee.

Executive Chairman, for conference entitled "Fifty Years with Nuclear

Fission" to be held at the NIST (April, 1989).

215
MAJOR CONSULTING AND ADVISORY SERVICES

Division 536, Ionizing Radiation

1. R. Colie assisted and advised the Radon Policy Subpanel of the

Committee on Interagency Radiation Research and Policy Coordination

in developing a report on the extent and adequacy of federal radon

programs

2. C. E. Dick consulted with Don Snyder, Eglin Air Force Base, on the new imaging methodologies in NDE for armament evaluation.

3. C. E. Dick consulted with John Cox, General Imaging Co., on evaluation of RAM imagers for real-time radiography.

4. C. E. Dick consulted with C. Richmond, Harry Diamond Labs., on coherence effects in Cherenkov radiation.

5. C. E. Dick consulted with R. Shives, Metallurgy, NIST, on radiography of steel plates from Pittsburgh oil tank collapse.

6. C. E. Dick consulted with Bill Lee, Eglin Air Force Base, on the

evaluation of DRAM imagers for armament evaluation.

7. David M. Gilliam advised and assisted Babcock and Wilcox (B&W) in

preparation and read-out of high-level gamma dosimeters, which are employed in mixed gamma and neutron radiation fields at the Oconee 2 and Davis Besse 1 nuclear power reactors. This novel measurement

technique, employing LiF single crystals, is proving highly

successful for assessment of radiation dose in power plant

environments, aiding operating utilities in safety assurance, power

plant life extension, and reduction of personnel dose.

8. David M. Gilliam assisted the dosimetry staff at the Armed Forces

Radiobiological Research (AFRRI) reactor in making reliable

measurements of neutron dose. The fission chamber monitor system

installed under NIST guidance is proving extremely useful in

resolving discrepancies between other less-direct instrumentation

systems. Accurate dosimetry is essential for AFRRI experiments

which are aimed at understanding biological effects of radiation and

advancing radiation therapy techniques.

9. H. T. Heaton, II consulted with the Illinois Department of Nuclear

Safety on designing a new calibration facility and computer code for

instrument calibration and quality control procedures.

216
Division 536, Major Consulting and Advisory Services (cont'd.)

10. H. T. Heaton, II consulted with the South Carolina Department of

Health and Environmental Control on the use of a computer code for

instrument calibration and quality control procedures.

11. H. T. Heaton, II consulted with the California Office of Emergency

Services on the use of a computer code for instrumentation and

quality control procedures.

12. J. H. Hubbell responded to 303 inquiries (technical advice, data,

bibliographic search, publication requests, referencing of journal

manuscripts, etc.) to the Photon and Charged Particle Data Center

during the reporting period, 10/01/87 to 06/30/88.

13. J. C. Humphreys provided advice and irradiation services on various

gamma-ray and x-ray facilities in the testing of a new phosphor

crystal- filter optic radiation detector system for Quantex

Corporation of Rockville, MD

.

14. J. C. Humphreys provided advice and design ideas for construction of

a graphite calorimeter to be used in the electron beam of a 10 MeV

research linear accelerator to the Atomic Energy of Canada, Ltd.,

Pinawa, Manitoba, Canada..

15. J. C. Humphreys and W. L. McLaughlin provided advice on appropriate

methods for dosimetry data analysis and statistical quality control

techniques to the Department of Food and Agriculture, State of

California (Joseph Rothleder) . A joint paper will be published on

that subject.

16. L. R. Karam consulted in chemical and biochemical procedures,

Imperial Cancer Research Fund, London.

17. E. D. McGarry provided consultation and 235 U Standard Neutron

Irradiations on a (successful) try-and-see basis, to Westinghouse

Electric Corporation's Research Division (Monroeville, PA), to

establish mass scales for ultralight fissionable deposits whose

masses are in the fractional nanogram cm2 range.

18. E. D. McGarry provided consultation to Materials Engineering Branch

of the Nuclear Regulatory Commission regarding benchmarking of

pressure vessel surveillance dosimetry.

19. W. L. McLaughlin consulted with Lew Devigli and Michael Hyman,

Science Applications International Corp . , San Diego, CA, on the

design and testing of field-operational optical waveguide dosimeters

for DoD , solving technical problems to permit meeting military

specifications

.

217
Division 536, Major Consulting and Advisory Services (cont'd.)

20. W. L. McLaughlin met with Dr. S. Kronenberg, Electronics and

Radiation Command, U.S. Army, Fort Monmouth, NJ , regarding design

and testing of a neutron and gamma ray personnel dosimeter for dose

and dose rate measurements over wide ranges

21. W. L. McLaughlin assisted C. R. Siebentritt and B. Thompson, Federal

Emergency Management Agency, Mount Weather Testing Facility,

Berryville, VA, in the design and testing of two types of emergency

dosimeters: one for low personnel doses (based on quartz-fiber

technique) ; and the other for emergency doses (based on optical

waveguide technique)

22. W. L. McLaughlin worked with K. C. Humphreys and W. Wilde, Far West

Technology, Inc., Goleta, CA, on the design and testing of new radiochromic and optical waveguide dosimeters and densitometers,

which are tailored for medical, industrial and agricultural

applications

23. W. L. McLaughlin, together with Dr. W. J. Chappas and Dr. M. AlSheikhly, Applied Technology Corporation, New Carrollton, MD , worked

on the invention of a new visually-read optical waveguide dosimeter

for personnel dosimeter (patent application made)

24. W. L. McLaughlin consulted with Dr. T. Prusik, Allied Corp . , New

Venture Group, Morristown, NJ , and went through extensive testing of

new "Lifelines" dosimeters based on bar-coded radiochromic labels

which are designed for food irradiation dosimetry.

25. W. L. McLaughlin, with J. M. Foley, Dr. David Lewis, and J. C.

Shiloff, GAF Corp., Wayne, NJ , discovered and extensively tested a new thin- film radiochromic dosimeter, which is now marketed by AECL,

Ltd., Canada, as GafChromic

26. W. L. McLaughlin, J. C. Humphreys and D. Hocken consulted with

Geraldine Barrett, Neutron Products, Inc., on devising quality

control methods for radiation sterilization of medical devices and

radiation processing of plastics, which included trouble-shooting

radiation processing commissioning, using radiochromic film

dosimeters

27. W. L. McLaughlin provided Ken Roth, NASA-ARAC, Indianapolis, IN,

detailed information and methods for food irradiation dosimetry for

quality control.

28. W. L. McLaughlin provided R. Schuler, Rockbestos Co., East Granby,

CT, calculations and measurements of electron beam depth-doses at

0.55, 1 and 3 MeV in order to determine beam energy.

218
Division 536, Major Consulting and Advisory Services (cont'd.)

29. W. L. McLaughlin worked with G. Pageau and S. Kruger, Iotech, Inc.,

Northglenn, CO, on making dose distribution measurements in medical

device packages being sterilized by 10 MCi 137 Cs source, for QA at

Iotech

.

30. W. L. McLaughlin provided Dr. Arne Miller, Ris0 National Laboratory,

Roskilde, Denmark, design and intercomparison measurements at Ris0

and at NPL using NIST graphite calorimeters as means of calibrating

the response of chemical dosimeters in high-energy electron beams.

31. W. L. McLaughlin consulted with J. W. Nam, Dosimetry Section,

International Atomic Energy Agency, Vienna, Austria, including

chairing an IAEA Advisory Group writing a Technical Report on guidelines on dosimetry for industrial radiation processing.

32. W. L. McLaughlin consulted with Dr. Athorn Patumasootra , Office of

Atomic Energy for Peace, Bangkok, Thailand, and set up a secondary

standards laboratory for high-dose radiation measurement

(industrial, agricultural, and medical applications).

33. W. L. McLaughlin worked with Dr. Fred Eichmiller, American Dental

Associates, NIST, providing advice and participating in dose distribution measurements in tissue phantoms, for cancer treatment

planning involving gamma ray irradiation of oral tumors next to

teeth and tooth restorations.

34. Robert B. Schwartz tested and evaluated neutron detectors for the N.

Wood Counter Laboratory.

35. Robert B. Schwartz worked with representatives of the Physikalisch - Technische Bundesanstalt and the University of Saarlands (Federal

German Republic) to evaluate use of tissue equivalent proportional

counters for low energy neutron dosimetry.

36. Robert B. Schwartz participated in an intercomparison of neutron

remmeters with National Physical Laboratory (U.K.); Commissariat a L'Energie Atomique (France); and Physikalisch - Technische

Bundesanstalt (FRG)

.

37. Stephen M. Seltzer did a series of transport calculations for bremsstrahlung production from low-and high-energy electron beams in

various targets for members of the Radiation Physics Group at the

Stanford Linear Accelerator Center, Stanford, CA.

219
Division 536, Major Consulting and Advisory Services (cont'd.)

38. Stephen M. Seltzer assembled an extensive suite of codes and cross- section databases, and instructions on their installation and use,

which were provided, to scientists requesting the tools for electron

and photon transport calculations. The requests came from members

of: the X-Ray Astrophysics Group, Department of Physics, The

University of New South Wales, Australia; the Radiation Division,

Varian Corporation, Palo Alto, CA; and the Computational Physics

Division, Lawrence Livermore National Laboratory, Livermore, CA.

39. Stephen M. Seltzer prepared and extensively tested new algorithms

for the sampling of energy- loss fluctuations in electron transport

for members of the Simulation Theory Division, Sandia National

Laboratory, Sandia, NM.

40. Stephen M. Seltzer, in response to a formal request to NIST for

assistance in methods of energy calibration for high-power

industrial accelerators used in radiation processing, performed a series of state-of-the-art Monte Carlo calculations of the

distribution of absorbed dose by electrons in a number of materials.

Extensive analysis was performed to relate penetration depth to

electron energy, and to compare present results to previous methods.

Results were supplied to Radiation Dynamics, Inc., Melville, Long

Island, NY and to Becton-Dickinson, North Canaan, CT

41. Stephen M. Seltzer prepared extensive tables of the bremsstrahlung

yield of electrons and photons for use in the calculation of photon

mass-energy transfer and absorption coefficients being done by

members of the Department of Radiation Therapy, Cleveland Clinic

Foundation, Cleveland, OH.

42. Stephen M. Seltzer collaborated with scientists at NASA's Goddard

Space Flight Center on the development of (a) a pattern-recognition

analysis of XRF spectra for the compositional classification of

geological samples (with application to the Mars Rover Mission) and

of alloy samples; and (b) a new method of deconvoluting multiplepinhole x-ray images for emission tomography.

43. Julian Sparrow consulted with Lynn Spence, Lockheed Missile and

Space Corp . , and Maynard Grove, Atlantic Research Corp . , on penetrameters to identify high and low density inclusion in rubber.

44. Julian Sparrow consulted with Lockheed and Atlantic Research

Corporation personnel on radiographic procedures to be used to

inspect missile motor components.

220
Division 536, Major Consulting and Advisory Services (cont'd.)

45. Julian Sparrow performed major advisory services on radiographic

inspection of rocket motors for the following groups: Jerry Lyman

and Richard O'Brien at the Strategic Weapons Facility, Pacific,

Bremerton, WA; Martin Johnson, Polaris Missile Facility Atlantic,

Charleston, SC; Dick Shaffer and Gary Barrett, Hercules, Bacchus,

Division, Magna, UT; and Kent Robertson, Morton-Thiokol Inc.,

Brigham City, UT.

221

2
JOURNAL EDITORSHIPS

Division 536, Ionizing Radiation

B. M. Coursey, Editor, International Journal of Radiation Applications and

Instrumentation, Part A. Applied Radiation and Isotopes.

B. M. Coursey, Editor, International Journal of Radiation Applications and

Instrumentation, Part B. Nuclear Medicine and Biology.

J. H. Hubbell, Editor, International Journal of Radiation Applications and

Instrumentation, Part A. Applied Radiation and Isotopes.

J. H. Hubbell, Editorial Board, Journal of the Nigerian Association of

Medical Physicists.

W. B. Mann, Editor-in-Chief for North America, International Journal of

Radiation Applications and Instrumentation, Part A. Applied Radiation

and Isotopes.

W. B. Mann, Editor-in-Chief for North America, International Journal of

Radiation Applications and Instrumentation, Part B. Nuclear Medicine and

Biology

W. L. McLaughlin, Editor in Chief, North America, International Journal of

Radiation Applications and Instrumentation, Part A. Applied Radiation

and Isotopes (succeeded Dr. W. B. Mann).

W. L. McLaughlin, Editorial Board, Radiation Physics and Chemistry.

M. G. Simic, International Editorial Board, Free Radical Biology and

Medicine

222
TRIPS SPONSORED BY OTHERS

Division 536, Ionizing Radiation

Martin J. Berger and Stephen M. Seltzer traveled to Erice, Sicily to be

instructors at the 8th Course: Monte Carlo Transport of Electrons and

Photons Below 50 MeV, International School of Radiation Damage and

Protection, Ettore Majorana Center for Scientific Culture. All expenses

were paid by the host organization (Sept. 24 - Oct. 3, 1987).

Randall S. Caswell traveled to Munich, West Germany to present an invited

paper and chair a session at the Sixth Symposium on Neutron Dosimetry;

and to attend a Workshop on Fast Neutron Radiotherapy. The Commission of

the European Communities provided partial subsistence and registration

fee (October 12-16, 1987).

Randall S. Caswell traveled to Helsinki, Finland to attend the Annual

Meeting of the International Commission on Radiation Units and Measurements

(ICRU). All expenses were paid for by the ICRU (August 14-21, 1988).

E. H. Eisenhower lectured at the Harvard course on Radiation Protection

Instrumentation in Boston, MA. All expenses were paid by Harvard University

(May 1988)

.

E. H. Eisenhower participated in on-site assessments of two Eberline

Instrument Corporation calibration laboratories, one in Santa Fe , NM, and

one in Columbia, SC. All expenses were paid by the Health Physics Society

(June 1988)

.

E. H. Eisenhower participated in a preliminary assessment of health physics

quality assurance program needs for the Oak Ridge National Laboratory.

Travel expenses were paid by ORNL (August 1988) .

David M. Gilliam travelled to Brighton, England for the purpose of preparing

a proton trap and neutron counter at the University of Sussex and to

carry out calibrations of boron and lithium isotopic targets at the BR-1

reactor. All expenses were paid by a N.A.T.O. grant (January, 1988).

H. T. Heaton, II, traveled to Columbia, South Carolina sponsored by South

Carolina Department of Health and Environmental Control for training state

personnel in computer procedures for instrument calibrations (October 13,

1987)

.

Kenneth G.W. Inn presented an invited seminar: Development of low-level

natural -matrix Radioactive Standards - Lung and Liver, and discussed the

interlaboratory data from assays of SRM 4351 and 4352 at the Los Alamos

National Laboratory, Los Alamos, New Mexico. All expenses were paid by

the Los Alamos National Laboratory (September 21-23, 1987).

223
Division 536, Trips Sponsored by Others (cont'd.)

Lisa R. Karam traveled to l'Institut Jacques Monod - Paris for a fellowship

under Dr. Miroslav Radman for the study of plasmid manipulations and

creation of deletion mutants. The l'Institut Jacques Monod paid for

lodging and subsistence (July 7 - October 6, 1987).

Lisa R. Karam traveled to London for a fellowship under Dr. Tomas Lindahl

for the study of the biochemistry of Ataxia Telangiectasia and the

elucidation of the AT phosphate modification, and purification of the

enzyme deoxyribophosphodiesterase . The Imperial Cancer Research Fund

paid for lodging and subsistence (December 16, 1987 - March 15, 1988 and

April 15-29, 1988)

R. Loevinger and J.T. Weaver traveled to Nashville, TN to take part in a site visit to K & S Associates, who were seeking accreditation by the

AAPM as a brachy therapy calibration laboratory. The travel expenses were paid by K & S Associates (October 4-5, 1987).

R. Loevinger traveled to San Francisco, CA and Boston, MA to take part in

meetings of the MIRD Committee of the Society of Nuclear Medicine. The

trips were paid for by the Society of Nuclear Medicine (November 19-20,

1987 and March 17-18, 1988).

R. Loevinger traveled to Ottawa, Canada, to give an invited talk at the

National Research Council Workshop on Water Calorimetry. Travel expenses

were paid by the National Research Council (June 6-8, 1988).

W. L. McLaughlin traveled to Ris0 National Laboratory to begin rewriting

a Report (formerly an ICRU Report Draft) on Dosimetry for Radiation

Processing and also to present an invited Colloquium on the subject of

this books. Ris0 National Laboratory paid for all expenses (October 26-

31, 1987).

W. L. McLaughlin traveled to Santa Barbara, CA to present colloquium on

"The Role of Dosimetry in Quality Assurance" at the International Conference

on Advancing Food Technology with the Irradiation Process. All expenses

were paid by Engineering Foundation Conferences (November 18-20, 1987).

W. L. McLaughlin traveled to Thailand to set up and calibrate a secondary

standards High-Dose Dosimetry Laboratory in the Office of Atomic Energy

for Peace (OAEP) . The travel expenses, lodging and subsistence were paid

by the International Atomic Energy Agency (March 6-April 1, 1988).

W. L. McLaughlin traveled to Brussels at the Biology Division of the

European Economic Community to work on a C.E.C. report on industrial

radiation measurements and quality control. Lodging and subsistence

expenses were paid by the C.E.C. (May 26-29, 1988).

224
Division 536, Trips Sponsored by Others (cont'd.)

W. L. McLaughlin traveled to Vienna to write a Protocol for Industrial

Radiation processing dosimetry for the International Atomic Energy Agency,

Vienna. The travel expenses, lodging and subsistence were paid by the

Ris0 National Laboratory, Roskilde, Denmark (May 30-June 1, 1988).

W. L. McLaughlin traveled to Oxford, UK to attend an Editors' meeting at

Pergamon Press, on Editorial Staff of the Journal, Applied Radiation and

Isotopes . Two days' subsistence were paid by Pergamon Press (June 6,

1988) .

Robert B. Schwartz traveled to Munich, FRG , in October, 1987, and to

Braunschweig, FRG, in June, 1988 to participate in meetings of the ICRU

Working Group on Practical Determination of Dose Equivalent. All expenses

for both trips were paid for by the ICRU (September 27-October 17, 1987

and May 28-June 8, 1988).

Oren A. Wasson traveled to Beijing, People's Republic of China, to lecture

and visit the following laboratories: Institute of Atomic Energy, Beijing;

National Institute of Metrology, Beijing; Research Institute of Xian

Petroleum Exploration Instrument Complex, Xian; Zhongshan University,

Guangzhou; Chinese National Analytical Center, Guangzhou. The IAE

,

Beijing, partially sponsored and paid his expenses while in PRC (June 5-

20, 1988).

225
STANDARD REFERENCE MATERIALS

Division 536, Ionizing Radiation

Radioactivity Group Standards Issued - 1 August 1987 through 31 July 1988

SRM Radionuclide Principal Calibration Use

4417L-F Indium- 1 1Activity measurements of

radiopharmaceuticals

4410H-L Technetium-9 9m

44061 Phosphorus 32

4407M Iodine-25

4401L-N Iodine- 13

4412L-M Molybdenum-99

4415L-L Xenon- 133

4416-1 Gallium-67

4404L-K Thallium-201

4400L-J Chromium-51

4339 Radium-228

,

Solution Source

Natural environmental

radioactivity monitoring

4919F Strontium-90

Solution Source

Detectors and radiochemical

separations of radiostrontium

4369 Gadolinium- 153

Solution Source

Irradiators for osteoporosis

measurements

4275C Long-Lived Mixed Radionuclide

Point Source

Germanium spectrometer

systems in the energy range

from 27 to 1596 keV

4276C Long-Lived Mixed Radionuclide

Solution Source

Germanium spectrometer

systems in the energy range

from 27 to 1596 keV with

custom sources

226
CALIBRATION SERVICES PERFORMED

Division 536, Ionizing Radiation Division

I. Radiation Interactions and Dosimetry Group

High-Dose Calibrations, FY-1988

Service

Customer

Classification

Type of

Service

No . of

Customers

No. of Tests

Performed

Fee

Income

Industrial

:

A 25 163 41,712.00

medical product B 3 6 3,747.00

sterilization C 7 7 57.50

Industrial

:

A 5 34 8,788.00

electronic B 10 33 14,787.00

hardness testing C 3 4 1,469.00

Industrial

:

A 0 0 0

polymer B 0 0 0

modification C 0 0 0

National Laboratory: A 0 0 0

electronic B 1 34 8,500.00

hardness testing C 0 0 0

Dept, of Defense: A 1 11 2,827.00

electronic B 1 4 1,845.00

hardness testing C 0 0 0

Secondary A 0 0 0

Calibration B 1 1 951.00

Laboratory C 0 0 0

University

:

A 0 0 0

research B 1 1 965.00

C 0 0 0

Subtotals

:

A 30 197 50,500.00

B 16 79 30,795.00

C 10 11 2,326.50

Grand Totals

:

XXX 57 297 86,448.50

Service Code Type of Service SP-250 Number

Irradiate Dosimeters 49010C

Supply Transfer Dosimeters 49020C & 49030C

Special Measurements 49040S & 49050S

A

BC

227
Division 536, Calibration Services Performed (cont'd.)

Customer SP-250 Number of

Tvne of Service Type* Item No. Tests Income

Calibration of x-ray

and y-ray measuring

instruments, and

irradiation of TL

dosimeters

1-8 46010-50 361 $157 k

Calibration of y-ray

and /3-particle sources

2-6 47010-40 19 16 k

Chemical dosimetry

measurement assurance

service for electron

beam

2 48010-20 146 29 k

Irradiation of TLDs

and preparation of

units for shipboard

measurements

Navy N . A

312 100 k

Instrument calibration 8 N. A. 1 20 k

^Column 2: 1, calibration labs

2, hospitals

3, nuclear establishments

4, industry

5 , US government labs

6 , DoD labs

7, universities

8, US government agencies

228
Division 536, Calibration Services Performed (cont'd.)

II. Neutron Interactions & Dosimetry Group

Type of Service Customer

No . of

SP- 250 Tests

Neutron

Protection

Instrumentation

NRC 44060C

Calvert Cliffs 44060C

Carolina P&L 44060C

Omaha Public Power 44060C

U . S . Army 44060C

Illinois Power 44060C

WPPS 44060C

Barlett Nuclear Corp

.

44060C

Eberline Instr. Corp. 44060C

Penn. Power & Light 44060C

Univ. Hospital, Tampa 44060C

1 17

13

24

2

3

12

1

Total 37

Neutron Source Oak Ridge National Lab 44010C 2 Calibration Westinghouse/Bettis

Lawrence Livermore

44010C 1

National Lab 44010C 1 U.S. Air Force 44010C 2

Sub Total 6

In-house (NBS) Sources N/A __7

Total 13

229
Division 536, Calibration Services Performed (cont'd)

III. Radioactivity Group

August 1, 1987 to August 1, 1988

Scheduled

Calibrations* Non- scheduled Tests

Number

of

Sources

Total

Fee

$k

Number

of

Sources

Total

Fee

$k

Cateeorv

Alpha-particle Sources

SP- 250 Nos. 43030C

,

43040C , & 43050C

16 11.5 8 16.5

Beta-Particle Solutions

and Gases ( 85 Kr)

-- -- 2 7.7

Gamma-ray Solutions,

Point Sources, and

Xe Isotopes

SP-250 Nos. 43010C

& 43020C

1 1.0 7 4.1

17 12.5 17 28.3

*SP-250 numbers refer to scheduled calibrations

230
SPONSORED SEMINARS AND COLLOQUIA

Division 536, Ionizing Radiation

Ken Zasadny, University of Michigan, Michigan, "Neutron Induced Activation

Studies at the University of Michigan," January 5, 1988.

Carl Ross, National Research Council, Ottawa, Canada, "Water Calorimetry,

with Emphasis on the Heat Defect," January 7, 1988.

R. J. Schultz, Yale University School of Medicine, New Haven, Connecticut,

"Absorbed Dose Measurements with a Water Calorimeter," January 7, 1988.

John R. J. Soreson, University of Arkansas for Medical Sciences, Little

Rock, Arkansas, "Copper Complexes Offer a Physiological Approach to

"Radiation Protection," April 15, 1988.

Steven D. Miller, Battelle Pacific Northwest Labs, Richland, Washington,

"Optically-Stimulated Luminescence in CaF2 :Mn," May 4, 1988.

Marlon L. Walker, Georgia Institute of Technology, Atlanta, Georgia,

"Effects of UV Photons on Isolated Lens Proteins," May 18, 1988.

David T. Burns, National Physical Laboratory, Teddington, Middlesex,

England, "The NPL High-Dose Graphite Calorimeter," June 9, 1988.

M. Roos , Physikalisch-Technische Bundesanstalt , West Germany, "Water

Calorimetry at the Physikalisch-Technische Bundesanstalt," June 13, 1988.

Hans G. Menzel, University of Saarlands, Homburg/Saarlands , West Germany,

"Proportional Counter Measurements in Low Energy Neutron Beams," June 27,

1988.

Bill Franklin, Imperial Cancer Research Fund, London, England, "DNA

Deoxyribophosphodiesterase , " July 1, 1988.

Frantisek Becvar, Charles University, Prague, Czechoslovakia, "Capture

Gamma-Ray Studies of Deformed Nuclei," July 5, 1988.

Hans Roehrig, University of Arizona, Tucson, Arizona, "Large Area X-Ray

Imaging with Storage Phosphors and Fiber Optic," July 12, 1988.

Mingyu Ye, University of Notre Dame, Notre Dame, Indiana, "A Radiolytic

Study of Oxidation of Aromatic Compounds by Pulse Radiolysis, Ion

Chromatography, and HPLC , " July 28, 1988.

231
Division 536, Sponsored Seminars and Colloquia (cont'd.)

Helmut Schuhmacher, Physikalisch - Technische Bundesanstalt , Braunschweig,

West Germany, "Implications of Tissue-Equivalent Proportional Counter

Measurements in Neutron Dosimetry," August 11, 1988.

Augustin Grau Malonda, C . I . E . M . A . T . , Madrid, Spain, "The NBS/CIEMAT

(Spain) Collaborative Program in Radionuclide Metrology Using Liquid

Scintillation Detectors," August 15, 1988.

N. J. Parks, University of California, Davis, California, "Radiation

Chemistry and Physics Problems in the Cellular, Subcellular and Molecular

Dosimetry of in vivo Radionuclides," August 16, 1988.

Johnny Hansen, Ris0 National Laboratory, Roskilde, Denmark, "Low- and

High-LET Particle Dosimetry by ESR Spectrometry of Amino Acids," August

18, 1988.

Colin Mailer, University of New Brunswick, Canada, "Dental Enamel as an

In Vivo Dosimeter," September 30, 1988.

Leopold Zuppiroli, Laboratoire des Solides Irradies, CEA, France, "Gammaray Dosimetry in the Megagray Range Using Organic and Inorganic Detectors,"

September 30, 1988.

232
TECHNICAL ACTIVITIES

Division 530.1 - Nuclear Physics Group

Experimental Activities . Experimental electro- and photo-nuclear

physics activities of the Nuclear Physics Group are now being carried out

exclusively in the user mode. We currently have active experiments at

the Bates linac, the Saskatchewan cw pulse stretcher ring, the Nuclear

Physics at Stanford Linear Accelerator Center (NPAS) facility, and the

Berkeley 88" Cyclotron.

We are analyzing data from an MIT Bates 2 3

3

• 2 3

8

U(e , e' f

)

experiment

performed in the quasifree and delta resonance regions at momentum

transfers near 2 fnf 1. Preliminary results for 238 u indicate a reduced

fission branch (roughly 1/3) in the quasifree region compared to the delta

region, where the fission branch is nearly 100 percent. The reduced

branching ratio indicates low residual energy in the daughter system

following nucleon knockout. This is difficult to reconcile with apparent

nuclear binding effects based on position of the quasifree nucleon

knockout peak relative to that for the free nucleon. Contrasting this

with results for 23

3

U, we find that the fission branch is nearer to 100

percent. We are attempting to correlate these observations to known

fission branching ratios for real photon absorption at low energies.

(NIST Spokesperson; W.R. Dodge, J.W. Lightbody Jr., J.S. O'Connell and

collaborators at Lund, MIT, and UNH)

We are currently planning a new experiment at Bates making use of

the new polarized beam capability. This experiment has received PAC

approval. We will attempt to measure the d(e,e'p)n cross section in an out-of-plane geometry. Asymmetry measurements should yield the first

observation of the fifth structure function, which results from

interference of charge and magnetic scattering. This measurement should

be sensitive to details of the NN potential relating to spin degrees of

freedom. For this experiment we are constructing a special purpose outof-plane spectrometer for detecting protons and a new beam polarization

monitor. (NIST Spokesperson: W.R. Dodge, J.W. Lightbody Jr., and J.S.

O'Connell and collaborators at MIT)

Recently the University of Saskatchewan at Saskatoon has

successfully produced a 300 MeV cw electron beam from their new

linac/pulse stretcher ring. The laboratory and PAC approved our proposal

to measure the 3 He(gamma, 2p) cross section looking for evidence of 3-body

forces. This experiment is the first to run at the new Saskatchewan

facility and is now in progress. We are using scintillator telescopes

for detectors, which provide energy, angle and particle ID information.

A high pressure gas cell is being used for a target. The kinematic

completeness of this reaction permits us to use the high flux provided by

233
a bremsstrahlung beam. Theoretical guidance is provided by calculations

of Laget. (NIST Spokesperson; W.R. Dodge, J.W. Lightbody Jr., J.S.

O'Connell and collaborators at UMD , Univ. of Saskatchewan)

Our group is also participating in the first (e,e'p) measurement at

SLAC/NPAS. NE16 was proposed to study the reaction A He(e,e'p) in

quasifree kinematics. The goal of this measurement is to address the

question of modifications to nucleon electromagnetic structure functions

in nuclear matter. The experiment was approved by the PAC and work is

proceeding to develop new detectors required for the two spectrometers

(1.6 and 8 GeV/c) . This experiment will be a collaboration of several

universities and labs: CEBAF, UVA, W&M, Stanford, and NIST. Our group is

constructing a new segmented scintillator hodoscope for the 8 GeV/c

spectrometer to reduce pile-up problems caused by the low duty factor at

SLAC. (W.R. Dodge, J.W. Lightbody Jr., J.S. O'Connell and collaborators

at CEBAF, UVA, W&M, Stanford)

In other work, we are participating in deuteron-deuteron capture

reaction studies at Berkeley. The goal of this work is to extract the dwave component, or deformation, of the alpha particle ground state. This

experiment requires use of a polarized deuteron beam from the 88"

cyclotron and a cryogenic target. Photons are detected in large Nal

detectors in coincidence with associated alphas. Angular distributions

have been taken at several energies. This work is still in progress.

(W.R. Dodge, E. Hayward, and collaborators at Duke University)

Polarizability of the nucleon remains a quantity of fundamental

importance relating to basic predictions of QCD, and plans are continuing

for the experimental study of both the electric and magnetic

polarizability using the new generation cw electron machines. The

photonuclear absorption cross section of the proton is dominated by the

delta-resonance, a magnetic dipole state. This resonance overlaps an electric dipole continuum and is followed at higher energies by other

pion-nucleon resonances of electric dipole and quadrupole character. It

is difficult to reconcile what we know about the total photo-absorption

cross section with the results of earlier and somewhat imprecise photon

scattering experiments, which conclude that the electric polarizability

is ten times the magnetic polarizability. The theoretical answer to this

problem might lay in a proper treatment of retardation effects.

Experimentally, the magnetic polarizability should be better determined.

One possiblility is to use a linearly polarized photon beam and measure

the scattering intensity along the polarization direction. (E. Hayward

and collaborators)

Finally, we are heavily involved in preparing proposals for CEBAF.

The $400M CEBAF project is the highest priority new construction project

in US Nuclear Science at this time, reflecting the preeminence of

electromagnetic nuclear physics, and is expected to be complete in 1994.

Letters of intent are being submitted relating to electron coincidence

reaction studies, (e,e'pi) and (e'e'2p), which will address the questions

234
of pion content in nuclei and the nature of short range NN correlations

in nuclear matter. (W.R. Dodge, E. Hayward, J.W. Lightbody Jr., L.C.

Maximon, and J.S. O'Connell)

Theory Activities . Theory activities of our group include: (1)

elementary particle physics work relating to searches for glueballs,

hybrids, etc., mass spectra of composite systems, mass mixing matrices

and the quark mass spectrum, formation of quark gluon plasmas, and

quantum field theory; (2) calculation of three-body bound state and

continuum wave functions using a separable potential expansion of the NN

interaction; (3) wide angle bremss trahlung theory, polarization phenomena

in off-axis bremsstrahlung and tagging, and radiative corrections to

positron and electron scattering; (4) modeling electron, proton, neutron,

and pion yields from electron and photon induced reactions; (5) study of

binding effects in quasielastic electron scattering; (6) muon catalyzed

fusion studies; and (7) calculation of backgrounds to neutrino cross section measurements relating to solar neutrino studies.

Elementary particle theory [item (1) above] focusses on spectroscopic issues, such as those relating to the existence of

composites of gluons, which are mediators of the strong interaction as described by the highly successful quantum chromodynamical (QCD) theory

of strong interactions. Predicted on very fundamental grounds, these

composites have so far eluded detection. Work has continued on glueball

and hadron spectroscopy, showing that earlier meson spectroscopic

calculations have been verified by J/psi radiative decay measurements at

SLAC and Orsay. Recently a new description of quark and lepton masses using Bardeen, Cooper, Shrieffer (BCS) mass matrices was formulated which

has provoked a great deal of interest in the elementary particle

community. (S. Meshkov and collaborators)

In a related area, nucleons and mesons are predicted to make a phase

transition to a quark-gluon plasma at sufficiently high temperatures.

Search for signatures of this transition in related high energy

experimental data and for the so called ignition point temperature are under study. (M. Danos and collaborators)

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 longrange part of the interaction, that part where the microscopic structure

of the vertex is unimportant, is being investigated from the standpoint

of a relativistic many-body system involving pion and nucleon derees of

freedom. A program based on these models is underway. (M. Danos and

collaborators)

235
In addition, work is continuing on understanding 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 gap,

which exhibits a Meissner-Ochsenfeld effect, and which can not be

described by perturbative quantum field theory. More particularly, it is

believed that these characteristics 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.

(M. Danos and collaborators)

Continuum calculations [item(2)] will be necessary to ultimately

describe any 3 He or 3 H break-up processes, and are therefore of intrinsic

fundamental interest. Solution of the three-body problem in nuclear

physics is only now becoming tractable, and on the outcome of such

studies rests any conclusions regarding the existence of 3-body forces.

This work has particular relevance to our group since our experimental

efforts are focussing on electro- and photo-disintegration experiments on few nucleon systems. (L.C. Maximon in collaboration with GWU)

Radiation theory calculations [item(3)] in support of experimental

programs at CEBAF, Saclay, and Saskatchewan are being carried out. The

wide angle bremsstrahlung work has been particularly interesting because

of its relation to luminosity limitations on the CEBAF Large Acceptance

Spectrometer, which is being built at a cost of $10-15M. The theory of

off-axis tagging is essential to polarized photon beam experiments at a number of new facilities. Such experiments are amongst the most

interesting of the possibilities provided by these new facilities. The

e

+

, e" work addresses the subject of dispersive corrections (essentially

two-step mechanisms) to the fundamental electron scattering process.

(L.C. Maximon collaboration with Illinois, Montreal, Saskatchewan, and

Saclay .

)

Nuclear reaction yield modeling for electro- and photo- induced

reactions is very important to design of experiments. Item (4)

represents development of a computer code now widely used to predict

background and accidentals in coincidence reactions at the new generation

cw electron accelerators. This type of information is vital to the

design of the CEBAF experimental program. Development of this code was driven by needs within our research program. (J.W. Lightbody Jr. and

J.S. O'Connell)

Item (5). A result of earlier experimental studies, including some by our group, was observation of a q-dependence of the separation energy

inferred from single-arm electron scattering in the quasi-free region.

This q-dependence can be understood on the basis of momentum dependent

optical potentials experienced by both nucleons and deltas within the

nucleus. (J.S. O'Connell in collaboration with the University of Lund.)

236
Muon catalyzed fusion research [item(6)] has recently gained

prominence with the observation of muons recycling and inducing as many

as 100-200 dt fusions per muon. Theoretical research is being conducted

to understand the nature of this effect, and potential use as an alternative energy source. This research involves elements of molecular

and nuclear physics. A small grant from DOE helps support this activity.

(M. Danos)

Understanding the solar neutrino flux remains one of the enigmas of

nuclear astrophysics. Interest in neutrino induced reactions prompted a study of backgrounds which limit the precision of neutrino detectors.

Muons from cosmic rays can induce activities which mimic and mask the

signature for several planned neutrino detectors. Calculations have been

performed to get a quantitative measure of this effect. This and other

work has prompted a close interaction with some of the large US groups

interested in the solar neutrino detection problem. ( J . S . O'Connell)

Within the Nuclear Physics group there is a growing vitality and

enthusiasm from strong 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 strong fundamental research program which makes full use of world class

facilities

.

237
INVITED TALKS

Division 530.01, Nuclear Physics Group

Danos , M. , "Theory of Muon Catalyzed Fusion," Muon Catalyzed Fusion

Workshop, Sanibel Island, FL, June 1, 1988.

Danos, M. , "Quantum Field Theory Anomalies," Center for Nuclear Research,

Dubna , USSR, July 5, 1988.

Danos, M. , "Muon Catalyzed Fusion," University of Paris, Orsay, July 26,

1988.

Danos, M. , "Theory of Muon Sticking in d-t-muon Fusion Incorporating

Nuclear Effects, "Muon Catalyzed Fusion Conference, Moscow, USSR, Dec. 7,

1987.

Dodge, W.R, "Moller Polarimeters for CEBAF Hall A," CEBAF Hall A

Workshop, University of Maryland, Dec 11, 1988.

Dodge, W.R. "Polarimeters at Bates," CEBAF Workshop, Newport News, VA,

March 12, 1988.

Hayward, E., "Nuclear Electromagnetic Interactions (16 Week Graduate

Course)," Duke University, Durham, NC , Fall 1987.

Hayward, E., "Polarizability of the Proton," University of Saskatchewan

Nuclear Seminar, Saskatoon, Canada, Sept. 16, 1988.

Lightbody, Jr., J.W., "The Study of Three-Body Forces with the

3 He(gamma,2p) Reaction," University of Maryland Nuclear Physics Seminar,

University of MD , College Park, MD , Sept. 29, 1987.

Lightbody, Jr., J.W., "Science Funding in the US," University of

Saskatchewan, Nov. 1987.

Lightbody Jr., J.W., "Requirements for an (e,e'2N) Program at CEBAF,"

CEBAF Hall C Spectrometer Workshop, Newport News, VA, Feb. 1988.

Lightbody, Jr., J.W., "Experimental Equipment Requirements for (e,e'2N)

Reaction Studies at CEBAF," CEBAF Summer Workshop, June 23, 1988.

Lightbody, Jr., J.W., "Physics Motivation for (e,e'2N) Reaction Studies,"

CEBAF Summer Workshop, Newport News, VA, June 24, 1988.

238
Division 530.01, Invited Talks (cont'd)

Maximon, L.C., "Bremsstrahlung in Nuclear Physics: Why and How Charged

Particles Radiate," Triangle University Laboratory, Duke University,

Durham, NC , Nov. 5, 1987.

Maximon, L.C., "Tagged Photons - Using Photons to Probe Nuclear

Structure," George Washington U., Washington DC, Feb. 26, 1988

Maximon, L.C., "Theoretical Aspects of Polarized Tagged Gammas," CEBAF

Workshop on Tagged Photons, CEBAF, Newport News, VA, March 24, 1988.

Maximon, L.C., "Wide-Angle Bremsstrahlung Background to Electron

Scattering , "CEBAF LAS Workshop, CEBAF, Newport News, VA, March 26, 1988.

Maximon, L.C., "Analysis of Wide-Angle Bremsstrahlung Measurements at the

University of Illinois," CEBAF LAS Workshop, CEBAF, Newport News, VA, May

20, 1988.

Meshkov, S., "A New Quark Mass Matrix," Aspen Winter Physics Conf.,

Aspen CO, Jan. 1988.

Meshkov, S., "A New Quark Mass Matrix," California Institute of

Technology, Pasadena, CA, March 1988.

Meshkov, S., "BCS Quark Mass Matrix," UCLA High Energy Physics

Phenomenology Seminar, UCLA, March 1988.

Meshkov, S., "BCS Quark Mass Matrix," UC Irvine High Energy Physics

Seminar, UC Irvine, Irvine, CA, April 1988.

Meshkov, S., "BCS Quark Mass Matrix," UC Riverside High Energy Physics

Seminar, UC Riverside, Riverside, CA, May 1988.

Meshkov, S., "Meshkov, Glueball and Meson Spectroscopy," 3rd Conference

on the Intersection of Particle and Nuclear Physics, Rockport, ME, May

1988.

Meshkov, S., "BCS Quark Mass Matrix," University of Arizona High Energy

Physics Seminar," University of Arizona, Tucson, Arizona, June 1988.

Meshkov

,

1988.

Meshkov

CO, July

S., "BCS Quark Mass Matrix,

S., "BCS Quark Mass Matrix,

1988.

University of Munich, Germany, July

Aspen Center for Physics, Aspen,

Meshkov, S., "Glueballs: Advances, Problems, and Mysteries," Brookhaven

National Laboratory, August 1988.

239
Division 530.01, Invited Talks (cont'd)

Meshkov, S., "BCS Quark Mass Matrix," CERN, Geneva, Switzerland, August

1988.

O'Connell, J.S., "Progress with Out-of-Plane Spectrometers," MIT Bates

Laboratory, Middleton, MA, Jan. 15, 1988.

O'Connell, J.S., "Quasi-free Pion Knockout," CEBAF, Newport News, VA,

Feb. 27, 1988.

O'Connell, J.S., "Electromagnetic Excitation of the Delta Resonance in

Nuclei," University of Lund, Lund, Sweden, June 8, 1988.

240

t ’ii
PUBLICATIONS

Division 530.01, Nuclear Physics Group

Asai, J., Caplan, H.S., del Bianco, W. , Maximon, L.C., and Skopik, M.

;

Cross Section and Linear Polarization of Tagged Photons; accepted for

publication in Canadian Journal of Physics.

Danos, M. , The QCD Vacuum, Maratea Summer School, W. Greiner, Ed., Plenum

Press ( 1987) .

Danos, M. , and Biedenharn, L.C., Anomalies in Lagrangian Field Theory,

Phys . Rev. D36 . 3069 (1987).

Danos, M. , Biedenharn, L.C., Stahlofen, A. A., and Rafelski, J., Theory of

Muon Sticking in d-t-muon Fusion Incorporating Nuclear Effects, Proc

.

Conference on Muon Catalyzed Fusion, Moscow, USSR, Dec. 7-11, 1987.

Dow, K. , Beck, D., Dodge, W.R, Lightbody Jr., J.W., Maruyama, X.K., et

al .

;

Longitudinal Response Functions and Sum Rules for Quasielastic

Electron Scattering from 3 H and 3 He; submitted to Physical Review

Letters

.

Friar, J., Lehman, D., and Maximon, L.C.; Coulomb Effects in Asymptotic

Normalization Constants: a Soluble Model; Phys. Rev. C37, 336(1988).

Heddle, D. and Maximon, L.C.; Landau Straggling of Positrons and

Electrons; submitted for publication Phys. Rev. C.

Jandel, M. , Danos, M. , and Rafelski, J., Active Target Production of Muons

for Muon Catalyzed Fusion, Phys. Rev. C37 . 403 (1988).

Kaus , P., and Meshkov, S.; BCS Quark Mass Matrix; accepted for

publication in Physics Letters A.

Lightbody, Jr., J.W. and O'Connell, J.S.; Modeling Single Arm Electron

Scattering and Nucleon Knockout by GeV Electrons; Computers in Physics,

Pg.57, May/June 1988.

Meshkov S.; Glueballs and Hadron Spectroscopy; Proceedings of 3rd

Conference on the Intersection of Particle and Nuclear Physics, Rockport,

ME, May 1988.

Meshkov, S., Glueballs: Advances, Problems, and Mysteries, Proceedings,

BNL Conference on Glueballs, Hybrids, and Exotic Hadrons, Brookhaven

National Laboratory, Upton LI, NY, August 1988.

241
Division 530.01, Publications (cont'd)

O'Connell, J.S. and Schima, F. ; Muon Induced Radioactivity in Underground

Detectors, accepted for publication in Phys . Rev. D

O'Connell, J.S. and Schroder, B.; Quasifree Electron Scattering on Nucleons in a Momentum Dependent Potential, submitted to Phys. Rev. C.

Rafelski, J. and Danos , M., Possible Signature for Early Hadronization

Mechanisms of Quark-Gluon Plasma, Phys. Letters B1 92 . 432 (1987).

Weller, H., Whitton, R.M., Langenbrunner , J., Hayward, E., Dodge, W.R.,

Kuhn, S., and Tilley, W.R.; The Energy Dependence of Polarization

Observables in the 2 H(d, gamma) A He Reaction; submitted to Physics

Letters B.

242
TECHNICAL & PROFESSIONAL COMMITTEE PARTICIPATION & LEADERSHIP

Division 530.01, Nuclear Physics

Danos , M.

Member Organizing Committee, Conference on Future Directions and

Applications of Muon Catalyzed Fusion, University of Arizona,

Tuscon, Arizona, Oct. 1988.

Delegate, US-USSR Exchange Program on Muon Catalyzed Fusion.

Hayward, E.

APS Executive Board, Division of Nuclear Physics.

Board of Directors, Southeastern University Research Association

(SURA)

.

Chairman, APS DNP Program Committee for Spring APS Meeting.

Lightbody, Jr., J.W.

Program Director, NSF Intermediate Energy Nuclear Physics

Program

.

Chairman & Board of Directors, CEBAF Users Group.

Program Advisory Committee, CEBAF.

National Advisory Board, CEBAF.

Program Advisory Committee, University of Saskatchewan

Accelerator Laboratory.

Maximon, L.C.

Vice-Chairman Elect, 1990 Gordon Research Conference on Photonuclear Reactions.

Meshkov, S.

Advisory Board, Aspen Center for Physics.

Chairman Organizing Committee, Aspen Winter Conference on Elementary Particle Physics.

243
Division 530.01, Technical and Professional Committee Participation and

Leadership (cont'd)

Meshkov, S.

Member, Interagency Seminar Series Organizing Committee.

O'Connell, J.S.

Editorial Board, Physical Review C.

Program Advisory Committee, University of Saskatchewan

Accelerator Laboratory.

244
MAJOR CONSULTING AND ADVISORY SERVICES

Division 530.01, Nuclear Physics

M. Danos , Consultant to DoE, Basic Energy Sciences Division, Muon

Catalyzed Fusion Program.

J.W. Lightbody Jr., Temporary Assignment, Program Director, NSF

Intermediate Energy Nuclear Physics Program.

245
TRIPS SPONSORED BY OTHERS

Division 530.01, Nuclear Physics Group

Danos , M. , Paris, France, to continue collaboration with V. Gillet and

Dr. Gogny at Saclay, by CEN, Paris.

Danos, M. , numerous trips to U. Texas, U. Fla., elsewhere, for Muon

Catalyzed Fusion research and oversight, by DoE.

Danos, M. , JINR, Dubna and the Kurchatov Institute of Nuclear Science,

Moscow, USSR, partially funded by the Kurchatov Institute of Nuclear

Science, Moscow, USSR.

Hayward, E. , Duke University to teach graduate course Fall Semester

1987, by Duke University.

Hayward E., University of California, Berkeley 88" Cyclotron Lab, Jan. &

March 1988, by Duke University.

Hayward E., University of Saskatchewan, Saskatoon, Canada, Sept. 16,

1988, by the University of Saskatchewan.

Lightbody Jr., J.W., CEBAF Program Advisory Committee meeting, CEBAF,

Newport News, VA, Oct. 1988, by CEBAF.

Lightbody Jr., J.W., numerous trips to university labs, conferences, and

meetings, for NSF Intermediate Energy Nuclear Physics Program oversight,

under auspices of NSF.

Meshkov, S., Aspen Center for Physics Winter Conference, Jan. 1988, by

California Institute of Technology.

Meshkov, S., Conference on the Intersections of Particle and Nuclear

Physics, Rockport, ME, May 1988, by Cal. Tech.

Meshkov, S., University of Arizona, Seminar, June 1988, by University of

Arizona

Meshkov, S., Brookhaven Workshop on Glueballs, Hybrids, and Exotic

Hadrons, August 1988, by Brookhaven National Laboratory.

O'Connell, J.S., University of Saskatchewan Accelerator Laboratory

Program Advisory Committee, August 15, 1988, by Saskatchewan.

O'Connell, J . S . .University of Lund, Sweden, for work on collaborative

research, by University of Lund

246
JOURNAL EDITORSHIPS

Division 530.01, Nuclear Physics Group

J.S. O'Connell, Physical Review C Editorial Board

247
SPONSORED SEMINARS AND COLLOQUIA

Division 530.01, Nuclear Physics Group

R. Eramzhyan, Institute for Nuclear Research, Moscow, USSR, Cluster

Effects in the Photodisintegration of Light Nuclei, August 16, 1988.

Boris Tulupov, Institute for Nuclear Research, Moscow, USSR, Damping of

Single Particle States in Medium-Heavy Spherical Nuclei, August 16, 1988

Brad Filipone, CalTech, Pasadena, CA, CalTech SLAC Experiments, July 22,

1988.

H. Arenhovel, Institut fur Kernphysik, Johannes Gutenberg Universitat,

Mainz, West Germany, Determination of the Neutron Electric Form Factor

with Polarized Beam and/or Target, August 2, 1988.

Jurgen Arends , Physikalisches Institut, Universitat Bonn, West Germany,

ELSA: Status and Plans, March 22, 1988.

Jurgen Ahrens, Max Planck Institut fur Chemie , Mainz, West Germany, MAMI

Status and Plans, March 22, 1988.

W. Greiner, Institute for Theoretical Physics, Frankfurt, West Germany,

Nuclear Shock Waves and the Equation of State, March 3, 1988.

248
LIST OF ACRONYMS

AAMI

AAPM

AFRRI

AMS

ANL

ANS

ANSI

APRES

APS

ASSI

ASTM

AT

BCS

BIPM

BNL

BSDF

CAD

CAM

CAMAC

CCEMRI

CCPR

CEA

CEA

CEBAF

CEC

CEN

CFR

CIEMAT

Cl PM

CIRRPC

CORM

CRCPD

CRR

CSEWO

DAMOP

DNA

DNA

DNP

DoC

DOD

DOE

Association for the Advancement of Medical Instrumentation

American Association of Physicists in Medicine

Armed Forces Radiobiology Research Institute

Accelerator mass spectrometry

Argonne National Laboratory

American Nuclear Society

American National Standards Institute

Angle Resolved Photoelectron Spectroscopy

American Physical Society

Airglow Solar Spectrometer Instrument

American Society for Testing and Materials

Ataxia Telangiectasia

Bandeen-Cooper-Schnei fe r Bureau International des Poids et Mesures

(International Bureau of Weights and Measures)

Brookhaven National Laboratory

Bidirectional Scattering Distribution Function

Computer-aided Design

Computer-aided Mechanical

Computer Automated Measurement and Control

Consultative Committee for Ionizing Radiations (to CIPM)

Consultative Committee on Photometry and Radiometry

(French) Atomic Energy

(U.S.) Council for Energy Awareness; also USCEA

Continuous Electron Beam Accelerator Facility

Commission of the European Communities

Center for Nuclear Research (France)

Center for Fire Research

Centro de Inve st igacione s Energeticas Medioambientales y

Technologicas

Comit£ International des Poids et Mesures

Committee on Interagency Radiation Research and Policy

Coordination, OSTP

Council for Optical Radiation Measurements

Conference of Radiation Control Program Directors

Center for Radiation Research

Cross Section Evaluation Working Group

Division of Atomic Molecular Optical Physics

Defense Nuclear Agency

Deoxyribose nucleic acid

Division of Nuclear Physics

Department of Commerce

Department of Defense

Department of Energy

249
ACRONYMS (Continued)

DOELAP

ORAM

DRp-ase

DRTIP

DTS

DWBA

Department of Energy Laboratory Accreditation Program

Dynamic random access memory

deoxyribosphosphod iesterase

Detector Response Transfer and Intercomparison Program

Dual thin scintillator

Distorted Wave Born Approximation

ECR

EML

ENDF

ENSDF

EPA

ESONE

ESR

ETL

ETRAN

EURAOOS

EURATOM

Electrically Calibrated Radiometer

Environmental Measurements Laboratory

Evaluated Nuclear Data File

Evaluated Nuclear Structure Data File

Environmental Protection Agency

European Standards on Nuclear Electronics

Electron spin resonance

Electro-Technical Laboratory (Japan)

Electron/photon Monte Carlo transport code

European Community Dosimetry Committee

European nuclear energy organization

FAA

FAS CAL

FASEB

FDA

FEMA

FEL

FIMS

FOS

FRG

FT

FTIR

FY

Federal Aviation Administration

Facility for Automatic Spectroradiometric Calibrations

Federation of American Societies for Experimental Biology

Food and Drug Administration

Federal Emergency Management Agency

Free Electron Laser

Fissionable Isotope Mass Standards

Faint Object Spectrograph

Federal Republic of Germany

Fourier Transform

Fourier Transfor Infrared

Fiscal Year

GB

GC/MS

GPIB

Great Britain

Gas chroma tography/ ma ss spectrometry

General Purpose Instrumentation Bus

HHDL

HPLC

HP

HPS

HSST

HVL

Hungary

Harry Diamond Laboratories

High performance liquid chromatography

Hewlett Packard

Health Physics Society

Heavy section steel testing

Half-value layer

IAE

IAEA

IAU

I CRM

Institute of Atomic Energy (Beijing, China)

International Atomic Energy Agency (Vienna)

International Astronomical Union

International Committee for Radionuclide Metrology

250
ACRONYMS (Continued)

ICRU

I EC

IEEE

IES

IMEKO

IMFP

IN EL

I NMM

I PTS

IR

I SNF

ISO

JAERI

JET

LANL

LAS

LRIR

LEED

LET

LINAC

LLNL

LMRI

LTEC

MAMI

MAP

MCNP

ME A

MIRD

MIT

MLD

MO A

MRG

NASA

NAS-NRC

NIST

NCAR

NCRP

NCSL

NDE

NOT

NESDIP

NIM

nm

International Commission on Radiation Units and Measurements

International Electrotechnical Commission

Institute of Electrical and Electronics Engineers

Illuminating Engineering Society

International Measurement Confederation

Inelastic Mean Free Path

Idaho National Engineering Laboratory

Institute for Nuclear Materials Management

International Practical Temperature Scale

In f rared

Intermediate Energy Standard Neutron Field

International Organization for Standards

Japan Atomic Energy Research Institute

Joint European Torus

Los Alamos National Laboratory

Lange Apentune Spectrometer

Low Background Infrared

Low Energy Electron Diffraction

Linear Energy Transfer

Linear Accelerator

Lawrence Livermore National Laboratory

Laboratoire de Metrologie des Rayonnesments Ionisants (France)

Lamp Testing Engineer's Conference

Mainz Microtron

Measurement Assurance Program

(computer code)

Materials Engineering Associates

Medical Internal Radiation Dose (committee)

Massachusetts Institute of Technology

Multi-layer Dielectric

Measurement quality assurance

Materials Research Group

National Aeronautical and Space Administration

National Academy of Sc ience s-Na t ional Research Council

National Institute of Standards and Technology

National Center for Atmospheric Research

National Council on Radiation Protection and Measurements

National Conference of Standards Laboratories

Nondestructive evaluation

Nondestructive testing

reactor pressure vessel mock-up experiment

Nuclear Instrumentation Module

Nanometer

251
ACRONYMS (Continued)

NML

NPAS

NPL

NRL

NRRS

NSF

NSLS

NTOFF

NVIS

NVLAP

National Measurements Laboratory

Nuclear Physics at Stanford Linear Accelerator Center

National Physical Laboratory (U.K.)

Naval Research Laboratory

Near resonance Rayleigh scattering

National Science Foundation

National Synchrotron Light Source

Neutron Time-o f-Fl ight Facility

Night Vision Imaging System

National Voluntary Laboratory Accreditation Program

OAEP

OIML

OMH

ONR

ORNL

OSA

OMEGA

Office of Atomic Energy for Peach (Thailand)

Office of International Legal Metrology

Office of Measures (Hungary)

Office of Naval Research

Oak Ridge National Laboratory

Optical Society of America

24 Beam Laser Facility at Rochester

PAC

PEP

PID

PRC

PSD

PTB

PTFE

PTW

PUD

PWR

Program Advisory Committee

Pauli Exclusion Principle

Post irradiation dosimetry

People's Republic of China

Photon Stimulated Desorption

Physikalisch-Technische Bundesanstalt (West Germany)

Polytetrafluoroethylene

Physikalisch-Technische Werkst’atten

Paired uranium detectors

Pressurized water reactor

OA

QCD

QED

QED

Quality assurance

Quantum Chromodyanimcs

Quantum Efficient Device

Quantum electrodynamics

RF

RIMS

RIS

RIT

ROC

RTM

Radio Frequency

Resonance Ionization Mass Spectrometry

Resonance Ionization Spectroscopy

Rochester Institute of Technology

Republic of China

Racetrack Microton

SCK-CEN

SDC

SEM

SEMPA

Studiecentrum voor Kernenergie-Centre d'Etude de l'Energie

Nucleaire (Belgium)

Strategic Defense Command

Scanning Electron Microscope

Scanning Electron Microscopy with Polarization Analysis

252
ACRONYMS (Continued)

SI

SIR

SIRIS

SLAC

SOLSPEC

SOLSTICE

SPIE

SPIPES

SRM

SRS

SSBUV

SSDL

SSTR

STM

STOS

SURA

SURF

SUSIM

Systeme International

International Reference System for activity measurements

Sputter Initiated Resonance Ionization Mass Spectrometry

Stanford Linear Accelerator Center

Solar Spectrometer

Solar Stellar Irradiance Comparison Experiment

The International Society for Optical Engineering

Spin Polarized Inverse Photoemission

Standard Reference Material

Synchrotron Radiation Source

Shuttle Solar Backscatter Ultraviolet Radiometer

Secondary standard dosimetry laboratory

Solid State Track Recorder

Scanning Tunneling Microscope

Space Telescope Optical Simulator

Southeastern Universities Research Association

Synchrotron Ultraviolet Radiation Facility

Solar Ultraviolet Spectral Irradiance Monitor

tca.p

TEPC

TEXT

TLD

TN

TUO

Time-correlated associated Particle

Tissue Equivalent Proportional Counter

Texas Experimental Tokamak

Thermoluminescent Detector

Technical Note

TEXT Users Organization

HMD

UNH

UPS

URPs

UV

UVA

University of Maryland

University of New Hampshire

Ultraviolet Photoemission Spectroscopy

Unique radiolytic products

Ultraviolet

University of Virginia

VENUS

VI AS

VIS

VME

VIJV

research reactor in Belgium

(computer code)

Visible

(computer bus system)

Vacuum Ultraviolet

WKB

W&M

WNR-PSR

Wentzel-Kramer s-Rrillouin

Wi 1 1 i am and Ma ry

Weapons Neutron Source-Proton Storage Ring (Los Alamos)

XCON

XGAM

XRF xuv

Photon cross section database

Photon cross section database

X-ray fluorescence

Soft X-Ray and Ultraviolet Wavelength Range, 4-50 nm

253
-
NBS-114A (REV. 2-8C

U.S. DEPT. OF COMM.

BIBLIOGRAPHIC DATA

SHEET (See instruction s)

1. PUBLICATION OR

REPORT NO.

NISTI R 88-3869

2. Performing Organ. Report No 3. Publication Date

NOVEMBER 1988

4.

TITLE AND SUBTITLE

Center for Radiation Research

1988 Technical Activities

5.

AUTHOR(S)

Chris E. Kuyatt

6.

PERFORMING ORGANIZATION (If joint or other than NBS. see instructions)

NATIONAL BUREAU OF STANDARDS

U.S. DEPARTMENT OF COMMERCE

GAITHERSBURG, MD 20899

7. Contract/Grant No.

8 . Type of Report & Period Covered

9.

SPONSORING ORGANIZATION NAME AND COMPLETE ADDRESS (Street. City. State, ZIP)

10.

SUPPLEMENTARY NOTES

Qj] Document describes a computer program; SF-185, FIPS Software Summary, is attached.

11.

ABSTRACT (A 200-word or less factual summary of most significant information. If document includes a si gnificant

bi bliography 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 1988 in the NIST 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; capitali ze only proper names ; and separate key words by semicolon s) Atomic radiation, ionizing radiation; measurement support; nuclear radiation;

plasma radiation; radiation instrumentation; radiation measurements;

radiation physics, radiation sources; radiometric physics.

13. AVAILABILITY

[_XJ Uni imited

| 1 For Official Distribution. Do Not Release to NTIS

jj] Order From Superintendent of Documents, U.S. Government Printing Office, Washington, D.C.

20402.

[X] Order From National Technical Information Service (NTIS), Springfield, VA. 22161

14. NO. OF

PRINTED PAGES

261

15. Price

$24.95

USCOMM-DC 6043-P80
!

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