NBS SPECIAL PUBLICATION

1976 Edition

U.S. DEPARTMENT OF COMMERCE/ National Bureau of Standards

SPECIAL TECHNICAL FACILITIES

at the National Bureau of Stanmrds
NATIONAL BUREAU OF STANDARDS

The National Bureau of Standards' was established by an act of Congress March 3, 1901. The

Bureau's overall goal is to strengthen and advance the Nation's science and technology and

facilitate their effective application for public benefit. To this end, the Bureau conducts

research and provides: (1) a basis for the Nation's physical measurement system, (2) scientific and technological services for industry and government, (3) a technical basis for equity in trade, and (4) technical services to promote public safety. The Bureau consists of the institute for Basic Standards, the Institute for Materials Research, the Institute for Applied Technology, the Institute for Computer Sciences and Technology, and the Office for Information Programs.

THE INSTITUTE FOR BASIC STANDARDS provides the central basis within the United States of a complete and consistent system of physical measurement; coordinates that system with measure- ment systems of other nations; and furnishes essential services leading to accurate and

uniform physical measurements throughout the Nation's scientific community, industry, and commerce. The Institute consists of a Center for Radiation Research, an Office of Measurement

Services and the following divisions: Applied Mathematics — Electricity — Mechanics — Heat — Optical Physics — Nuclear

Sciences" — Applied Radiation" — Quantum Electronics^ — Electromagnetics'' — Time and

Frequency ^ — Laboratory Astrophysics ^ — Cryogenics ^

THE INSTITUTE FOR MATERIALS RESEARCH conducts materials research leading to improved

methods of measurement, standards, and data on the properties of well-characterized materials needed by industry, commerce, educational institutions, and Government; provides advisory and

research services to other Government agencies; and develops, produces, and distributes standard reference materials. The Institute consists of the Office of Standard Reference Materials and the following divisions: Analytical Chemistry — Polymers — Metallurgy — Inorganic Materials — Reactor Radiation —

Physical Chemistry.

THE INSTITUTE FOR APPLIED TECHNOLOGY provides technical services to promote the use of available technology and to facilitate technological innovation in industry and Government;

cooperates with public and private organizations leading to the development of technological standards (including mandatory safety standards), codes and methods of test; and provides

technical advice and services to Government agencies upon request. The Institute consists of a Center for Building Technology and the following divisions and offices: Engineering and Product Standards — Weights and Measures — Invention and Innovation —

Measurement Engineering — Structures, Materials, and Life Safety* — Building Environment* — Technical Evaluation and Application* — Fire Technology — Product Evaluation Technology.

THE INSTITUTE FOR COMPUTER SCIENCES AND TECHNOLOGY conducts research and provides

technical services designed to aid Government agencies in improving cost effectiveness in the conduct of their programs through the selection, acquisition, and effective utilization of automatic

data processing equipment; and serves as the principal focus within the executive branch

for the development of Federal standards for automatic data processing equipment, techniques,

and computer languages. The Institute consists of the following divisions: Computer Services — Systems and Software — Computer Systems Engineering — Information Technology.

THE OFFICE FOR INFORMATION PROGRAMS promotes optimum dissemination and accessibility of scientific information generated within NBS and other agencies of the Federal Government; promotes the development of the National Standard Reference Data System and

a system of information analysis centers dealing with the broader aspects of the National Measurement System; provides appropriate services to ensure that the NBS staff has optimum

accessibility to the scientific information of the world. The Office consists of the following

organizational units: Office of Standard Reference Data — Office of Information Activities — Office of Technical

Publications — Library — Office of International Relations.

> Headquarters and Laboratories at Gaithersburg, Maryland. Unless otherwise noted: mailing address Washington D C

20234. -Part of the Center for Radiation Research.

^ Located at Boulder, Colorado 80302.

* Part of the Center for Building Technology.
Special

Technical Facilities

at the

National Bureau of Standards

H. L Mason and Iris M. Lloyd

Editors

U.S. DEPARTMENT OF COMMERCE, Elliot L. Richardson, Secretary

James A. Baker, III, Under Secretary

Dr. Betsy Ancker-Johnson, Assistant Secretary for Science and Technology

NATIONAL BUREAU OF STANDARDS, Ernest Ambler, Acting Director

Issued March 1976

i
National Bureau of Standards Special Publication 413

Nat. Bur. Stand. (U.S.), Spec. Publ. 413, 1976 Edition, 50 pages

(Mar. 1976)

Supersedes NBS Special Publication 413, 1975 Edition

U.S. GOVERNMENT PRINTING OFFICE

WASHINGTON; 1976

For sale by the Superintendent of Documents, U.S. Government Printing Oi^ice, Washington, D.C. 20402

(Order by SD Catalog No. C13, 11:413/1976 Ed.) Price $1.35
FOREWORD

For nearly seventy-five years, the National Bureau of

Standards has been a national resource—a resource devoted

to the development of that vast network of measurements

and standards by which we define our societal existence.

As one of the nation's largest physical science laboratories,

the Bureau houses a number of special facilities which

serve a vital role in addressing questions of basic research

as well as technology application. One facility that has been

improved this year is the Synchrotron Ultraviolet Radiation

Facility. Having been converted into a storage ring, the

facility is now capable of producing 100,000 times as much

ultraviolet radiation and is being used on projects yielding

standards and data meeting needs ranging from controlled

nuclear fusion energy sources to fabrication of miniaturized

electronic circuits. As a national resource, these facilities are available for cooperative use. The purpose of this catalog is to inform scientists about the existence,

capabilities and availabilities of the equipment and facilities at the National Bureau of Standards.

Ernest Ambler

Acting Director

On the cover . . . Close-up view of a simulated experimental arrangement for laser excitation of a gas in the High Temperature Vaporization Laboratory. A laser beam is shown crossing a stream of gas directed at the sampling cone

of a mass spectrometer. The bright spot visible at the intersection of the laser beam and the gas stream represents the region of

initial excitation.
TABLE OF CONTENTS

Page

INTRODUCTION 1

ACCELERATORS

Electron Van de Graaff Accelerator, 4 MeV .... 2 Linear Electron Accelerator (LINAC) 2

Positive-Ion Van de Graaff Accelerator, 3 MEV . 3 Synchrotron Ultraviolet Radiation Facility

(SURF) 3

ACOUSTIC FACILHIES

Acoustic Anechoic Chamber 4

Acoustic Reverberation Chamber 4

ANTENNAS

Antenna Measurement Facilities 5 Rooftop Antenna Test Facility 6

BUILDING RESEARCH FACILITIES

Accelerated Weathering Laboratories 6

Plumbing Research Laboratory 7

Structures Laboratories 7

Thermal Engineering Laboratories 8

Thermographic Equipment 9 CALORIMETERS

Fluorine Combustion Calorimeter 10

Low-Temperature Adiabatic Calorimeter 10

Microcalorimetry 11 Platinum-lined Adiabatic Solution Calorimeter . 12

Rotating, Platinum-lined, Adiabatic Bomb

Calorimeter 12

COMPUTER

Central Computer Facilities 13

Automation Laboratory 13

ELECTRICAL MEASUREMENTS FACILITIES

Automatic Network Analyzer 14

Page

Electro-optical High Voltage Field Mapping

Systems 15

Non-Magnetic Facility 15 Reactance Bridge for Power Loss Measurement . 16

ELECTRON MICROSCOPES

Scanning Electron Microscope 16

Transmission Electron Microscope, 200 kV . . . , 17

ENVIRONMENTAL FACILITIES

Chlorine Flux Monitor 18

Precision Humidity Measurement 18

FIRE RESEARCH

Fire Research Laboratory 19

HIGH PRESSURE FACILITIES

High Pressure Generators 20

High Pressure Optical Fluorescence System .... 20

High Pressure PVT Dilatometer 21

HIGH TEMPERATURE FACILITIES

Alloy Preparation Laboratory 21 High Temperature Controlled-Atmosphere

Furnace 22

High Temperature Vaporization Laboratory ... 22

Inorganic Glasses: Preparation and Viscosity ... 23

Laser Materials Facility 23

Millisecond High Temperature Thermophysical

Measurements 24

LOW PRESSURE FACILITY

Mercury Manometer 24

LOW TEMPERATURE FACILITIES

Acoustical Thermometer 25
Page

Cryogenic Flow Research Facility 25

Hydrogen Liquefaction Facility 26

Liquefied Natural Gas Flow Facility 26

MACHINE TOOLS, NUMERICALLY CONTROLLED

Machine Tools, Numerically Controlled 26

MECHANICAL MEASUREMENT FACILITIES

Deadweight Force Calibration Machines 27

Fluid Flow Measurement 28

Three-Dimensional Precision Measurement .... 28

Universal Testing Machine, Twelve Million

Pound-Force 29

Wind Tunnel for Unsteady Flows 29

NUCLEAR REACTOR AND ASSOCIATED

FACILITIES

Nuclear Reactor 30

Filtered Neutron Beams 30

Intermediate-Energy Standard Neutron Field (ISNF) 31 Isotope Separator Laboratory 31 Neutron Diffractometers 32

Neutron Radiography Facility 33

Neutron Scattering Spectrometer 33

Nuclear Irradiation Facilities 34

Time-of-Flight Neutron Spectrometers 34

RADIOACTIVE SOURCE

Coba!t-60 Irradiation Facility 35

RADIO STATIONS

WWVL VLF Broadcast Station 35

Special Announcements on WWV/WWVH .... 36

SPECTROSCOPY FACILITIES

Analytical Spectrophometer 36

Page

Concave Crating Spectrographs, 10.7m 37

Czerny-Turner High-Dispersion Spectrograph . . 37

Electron Energy Loss Spectrometers for Cases . . 38

Far Infrared Spectroscopy 38

Flame Emission Spectrometer with Repetitive

Optical Scanning 38

Flash Photolysis Resonance Fluorescence

Apparatus 39

Fourier Transform Nuclear Magnetic

Resonance Spectrometer 39

Gas Chromatograph-Mass Spectrometer System . 40

High Pressure Photoionization Mass

Spectrometer 40

High Resolution Infrared Spectrometer 41 Isotope Ratio Mass Spectrometers 41 Microwave Spectroscopy Facility 41 Mossbauer Spectroscopy of Metals 42

Multichannel Flame Spectrometer 42

Nuclear Magnetic Resonance Spectroscopy .... 43

Photoionization Spectrometry 43

Raman Spectroscopy 44

SURFACE PROPERTIES FACILITIES

Electron Probe Microanalyzer 45

Ion Probe Microanalyzer 45

Molecular Beam-Field Emission Microscope .... 46

Molecular Beam Machine 46

Surface Analysis Facility 47

Surface Area Analyzer 47

X-RAY FACILITIES

Rotating X-Ray Anode Diffraction Unit 48

Soft X-Ray Spectrometer 48

Three-Circle X-Ray Diffractometer 49

INDEX 50

V

INTRODUCTION

Among the major technical facilities of the NBS lab- oratories in Gaithersburg, Md., and Boulder, Colo,

are some which are unique and many which feature equipment that is relatively uncommon. These important resources deserve to be more widely known

and used by the scientific and engineering community, including the Bureau's own staff, other Government agencies, industrial research associates, aca- demic researchers, and postdoctoral fellows. However, it should be noted that the Bureau cannot

accept work for these facilities which is more appropriately done by other organizations in or outside of the Federal Government.

Those facilities which are available for shared use, either occasional or extended, are briefly described

in the pages of this publication. For each is indicated

its technical capabilities, its potential applications,

and whom to contact in making arrangements. Litera- ture references which give more detailed information

as to the structure and usefulness of these facilities are included for many of the units described. While

there will be no charge made for use of the facility

by NBS workers on RTS-funded projects, all activities funded from outside NBS will be required to pay costs intended to recover operating expenses. The staff will be glad to discuss with interested individuals a specific research or testing problem for which the

equipment appears appropriate. Long term projects

require a written agreement which specifies the ex- tent of the participation of the staff responsible for

the facility, the allocation of costs, and the provisions

for publication of research results. NBS capabilities related to scientific and technical

equipment include also: Calibration to U.S. national standards—contact J. M. Cameron, Chief of the Office of Measurement

Services, Physics Building, Room A345, Phone 301/

921-2805.

Provision of well-characterized substances—contact J. P. Cali, Chief of the Office of Standard Ref- erence Materials, Chemistry Building, Room B306,

Phone 301/921-3479.

Information on evaluated data for physical properties—contact Dr. D. R. Lide, Jr., Chief of the Office

of Standard Reference Data, Administration Building,

Room A537, Phone 301/921-2467.

Information on U.S. and foreign documents on vol- untary engineering standards—contact W. J. Slattery,

Standards Information Services, Technology Building,

Room B160, Phone 301/921-2587.

Information on automatic data processing equipment and standards—contact Chief of Computer in- formation. Technology Building, Room B246, Phone

301/921-3517.

Visitors will find the Gaithersburg laboratories 20

miles northwest of Washington, D.C. (mail address,

National Bureau of Standards, Washington, D.C. 20234) and the Boulder laboratories 25 miles north- west of Denver, Colorado (mail address. National Bureau of Standards, Boulder, Colo. 80302).

Micrograph made with the TRANSMISSION ELECTRON

MICROSCOPE of the region surrounding a 200 gram Vickers microhardness indentation in sapphire (a-AhOj). The instru- ment is being used to study plastic deformation and the

structure of cracks (at C) in hard brittle materials.

1
ACCELERATORS

LINEAR ELECTRON ACCELERATOR. Linac beam handling

system.

ELECTRON

VAN DE GRAAFF

ACCELERATOR, 4 MeV

This accelerator, based on the principle of the Van de

Graaff electrostatic generator, produces both contin- uous and pulsed beams of electrons with good energy

resolution and continuous control of beam current and energy. Its capabilities make possible a wide

variety of experiments using electrons or photons.

Capability:

ENERGY: continuously variable 0.8 to 4.0 MeV.

ENERGY SPREAD: 0.2 percent.

OUTPUT CURRENT: 10-» to lO -' ampere dc. 500 microamperes peak

current pulsed.

PULSE LENGTH: 1 microsecond.

REPETITION RATE: 50 to 500 pps or single shot. EXPERIMENTAL ROOMS: two, well shielded,

total area 200 m^.

Applications: Interactions of electrons and photons

with matter; dosimetry measurements; isomer activation; electron channeling in solids; bremsstrahlung

production studies; characteristic radiation production; nuclear activation; photofission experiments;

radiation simulation measurements; radiation damage

and failure studies.

Availability: Beam time is available to NBS staff, other

agency and university users, industrial users, and

guest workers. Operation only by qualified X-Ray

Physics Section staff, under Dr. Charles E. Dick.

Literature: NBS Technical News Bulletin, August 1962,

Vol. 46, No. 8, pages 107-110.

Contact: Dr. C. E. Dick, Applied Radiation Division,

Radiation Physics Building, Room C216, Phone 301-

921-2201.

LINEAR ELECTRON

ACCELERATOR (LINAC)

The linear accelerator (linac) facility was designed for maximum flexibility, beam quality, and beam handling to satisfy the needs of a large variety of pro- grams. It is a high-intensity source of electron, photon, and neutron beams with excellent stability and

definition.

Capability:

ENERGY: continuously variable 10 to 150 MeV.

POWER: 60 kilowatts, average. CURRENT: 0.6 milliamperes, average.

3.5 amperes, peak (short pulse operation).

REPETITION RATE: variable to 720 pps. PULSE LENGTH: 0.001 to 5 microseconds.

ENERGY SPREAD: from linac, 2 percent full width

at half maximum; from beam handling sys- tem, 0.04 percent full width at half maxi- mum.

EXPERIMENTAL ROOMS: four, with personnel

access to one while beam is directed into another.

An on-line data handling system is available, and

data reduction programs are available.

Applications: Neutron total cross section measure- ments by time of flight (above-ground facility); neutron fission yields; neutron flux standards; neutron

capture cross sections; fast neutron activation analysis; electron and photon dosimentry; pulsed radiolysis of biochemical systems; electron scattering; elec- trodisintegration of light nuclei; photonuclear physics

with monoenergetic and polarized photons; photon

activation analysis; dosimetry and dose distribution using radiochromic dyes; electron and photon beam

measurement standards; production of radioactive

sources.

Availability: Beam time is available to NBS staff, other

agency and university users, industrial users, and

guest workers. Operation only by qualified Linac

Operations Section staff under J. E. Rose.

Literature: NBS Technical News Bulletin, August 1962,

2
Vol. 46, No. 8, pages 107-110. Scientific Research, June 1966, Vol. 1, No. 6, pages 24-26.

Contact: Dr. C. D. Bowman, Chief of Nuclear Sciences

Division, Radiation Physics Building, Room B119,

Phone 301-921-2234.

POSmVE-ION

VAN DE GRAAFF

ACCELERATOR, 3 MeV

The positive-ion 3 MeV Van de Craaff facility at the

National Bureau of Standards has been designed primarily for experiments involving keV and MeV energy

neutrons. It includes a HVEC model KN-3000 Van de

Craaff accelerator and two target rooms. The accel- erator is capable of operation in dc mode as well as

in a variety of pulsed beam modes. Momentum an- alyzed beams can be supplied to any of six ports in a low scattering environment or to a single port in a heavily shielded room. Protons and deuterons are the

ion species routinely accelerated.

Capability: Values listed are routinely available. Ex- tended capabilities may be developed for special

applications.

ENERGY: 0.8 to 3.0 MeV.

BEAM INTENSITY: 1 to 200^.

Analyzed Beam:

ENERGY: protons—0.8 to 3.0 MeV; deuterons—

0.8 to 2.8 MeV.

BEAM INTENSITY: 0.3 to 20.9/xA. ENERGY STABILITY: 2.0 keV.

ENERGY REPRODUCIBILITY: 5.0 keV.

Pulsating Capability:

Rf PULSING: 1.0 and 3.3 MHz repetition rates with 15 and 4 ns burst width respectively.

"Slow"pulsing: Burst width—variable from

0.1 to 5.0 ^s; Rep. rate—variable from 100

kHz to dc. An on-line data handling capability based on a DC 6024/5 computer is available. Applications: Standard neutron cross section measurements, neutron flux standards, neutron experiments involving time of flight, neutron capture cross section measurement, fast neutron activation analysis, neutron dosimetry, radiation damage studies, charged

particle studies.

Availability: Accelerator time is available to NBS staff and outside users to the extent that the work does i not conflict with the neutron standards program. The ! use of a member of the Van de Craaff staff is recom- mended for operation of the machine and set-up. Contact: Dr. A. D. Carlson, Neutron Standards Secj tion. Radiation Physics Building, Room B119, Phone

301-921-2677. I

SYNCHROTRON

ULTRAVIOLET RADIATION

FACILITY (SURF)

Synchrotron radiation in the far ultraviolet is highly

coliimated, nearly linearly polarized, and of calculable

intensity. It is well-suited for studies in atomic, molecular, biomolecular and solid-state physics, chemistry,

engineering and medicine.

Capability: The NBS Synchrotron Ultraviolet Radiation Facility (SURF) has been converted into a storage

ring. Beam currents of 2 mA have been accelerated

and two beam lines are operative. The third beam

line should be available in 1976. With a microtron injector the storage ring is expected to accelerate

a 40 mA beam to a maximum energy of 260 MeV.

The expected intensity in the region 600 A to 1200 A

is 3 X 10" photons per second per milliradian of

orbit for an instrumental resolution of AX/X = 0.001. Instrumentation planned and existing includes:

a) A source of smooth, calculable intensity distri- bution, 10,000 A to 40 A.

b) 600 A — 40 A 3-m grazing incidence spectrograph and monochromator, resolution to 0.05

A.

c) Two 2000 A — 60 A monochromators (toroidal

grating), resolution 0.5 A to 1.0 A.

d) 925 A — 40 A 2.2-m grazing incidence monochromator, resolution to 0.1 A, with 10^" torr vacuum chamber, photoelectron analyzer,

and manipulators.

e) Medium temperature heat-pipe ovens, 0.3m

and 1.0m, to 1100 C. One oven of the rotating

type handles materials that wet a wick with

difficulty.

f) Calibrated detectors, 2000 A — 200 A.

g) Two spectrometer calibration lines with a

direct view of the beam.

Applications: The enlarged SURF will be used for atomic and molecular absorption spectroscopy, optical properties of materials, electron density of states

in solids, surface studies (including angular distribu- tion of photoelectrons as a function of angle of inci- dence and polarization vector), radiation damage

studies in substances (including those of biological

origin), calibration studies, precision photoabsorption

cross-section measurements in solids and vapors, and

photoelectron spectroscopy of gases.

Availability: To any qualified research worker from

NBS or other Federal agencies. Contact: Dr. Robert P. Madden, Chief, Far UV Physics

Section, Physics Building, Room A251, Phone 301-

921-2031.

3
ACOUSTIC

FACILITIES

ACOUSTIC ANECHOIC CHAMBER, completely lined with sound absorbing wedges.

ACOUSTIC

ANECHOBC CHAMBER

This facility consists of a sound and vibration-isolated room whose inner surfaces are lined with 1.78-meter

long glass-wool wedges and whose free-field dimensions are about 10 X 6.7 x 6.7 meters. Access to the room is by means of a steel wire mesh floor sup- ported by concealed I-beams. Instrument hangers,

each capable of supporting about 100 kilograms, are mounted on all six surfaces of the room. The space is lighted, air conditioned and provided with electrical outlets and conduits for communications cables.

Capability: The room provides good free-field sound

conditions from about 50 Hz to at least 63 kHz. Upper

bounds for wide-band ambient noise are about 30 dB

re 20 /xN/m2 for C-weighting and 23 dB for Aweighting. (The actual ambient level cannot be measure with a commercial sound level meter since

equivalent instrument noise exceeds the ambient

acoustic noise.)

Applications: Microphone calibration, loudspeaker

measurements, sound level meter calibration, noise

measurement, psychoacoustic experiments, radiation

and scattering experiments, general use when a quiet

environment is needed.

Availability: When not otherwise in use and when

staff members are available to ready the facility for the user.

Literature: J. Acoust. Soc. Amer., Vol. 52, No. 4 (Part

1), Oct. 1972, pp. 1071—1076.

Contact: Dr. E. Magrab, Sound BIdg., Room B106,

Phone 301-921-3607.

ACOUSTIC

REVERBERATION

CHAMBER

The chamber is a vibration-isolated, shell-within-shel! type structure of massive reinforced concrete construction with inside dimensions of 9.14 X 7.62 X

6.10 meters. A steel plate, double-leaf entrance door

provides a clear opening to the chamber of approximately 2X3 meters. The chamber is equipped with

a unique set of adjustable, variable-speed, rotating vanes to improve the diffusion of the sound field. The

interior of the chamber and the surrounding one- meter-wide air envelope are lighted, air conditioned

and humidity-controlled and provided with electrical outlets and conduits for communication lines. Nu- merous pipe-sleeve openings of various sizes also are available for other specialized uses such as conduits for hydraulic, pneumatic, fuel or exhaust lines.

Capability: Although experimental verification has not been completed, the chamber is designed to pro- vide a highly diffuse sound field in the frequency

range 100 to 4000 Hz, and to permit reasonably

accurate acoustical measurements to be made at fre- quencies as low as 80 Hz and as high as 10,000 Hz. The wide-band ambient noise level in the chamber

with the vanes stationary is about 30 dB re 20 ^N/m^

for C-weighting and about 36 dB with vanes rotating

at 5 rpm. The reverberation time Tgo (60 decibel

decay) is approximately 25 seconds at 100 Hz and

about 4 seconds at 4000 Hz.

Applications: The chamber generally is used for measurement of sound power output of noise and

sound sources (e.g., machinery, appliances, loudspeakers, sirens), sound absorption of architectural materials (e.g., acoustical tile, carpeting, drapery),

random incidence calibration of sound level meters,

microphones and noise exposure meters, and human

response to noise.

Availability: When not otherwise in use and when

staff members are available to prepare the facility for the user.

Literature: NBS Tech. News Bui., Vol. 52, No. 12, Dec.

1968. Contact: Dr. I. Pallett, Sound Building, Room A155,

Phone 301-921-3381.

4
ANTENNAS

NEAR-FIELD SCANNING FACILITY for measurement of gain, pattern, and polarization characteristics of microwave

antennas. Ttie panels of pyramidal wedges prevent re- flections.

ANTENNA

MEASUREMENT FACILITIES

The Electromagnetic Division of the NBS Boulder

Laboratories has recently perfected two new and

highly accurate methods for determining antenna

characteristics from measurements made at greatly

reduced distances. The methods are known as the near field scanning (NFS) and extrapolation tech- niques and two types of unique facilities have been

constructed in order to implement them.

1. Near-Field Scanning Facility

Capabilities: This facility is used to measure the nearfield phase and amplitude over a plane area close to the test antenna. From this information it is possible

to accurately calculate the gain, pattern, and polarization characteristics at all distances from the antenna, near field as well as far field. The absolute

gain can be determined to within about ± 0.15 dB,

the polarization axial ratio to within about ±0.10 dB/

dB and side lobe levels can be obtained down to —50 or —60 dB. The side lobe accuracy is typically

about ±1.0 dB at the —40 dB level. (The exact uncertainties will depend on the frequency, type, and

size of antenna, etc.) The new automated system is capable of scanning an area 15 ft X 15 ft square and

can be adapted to take data over a cylindrical or

spherical surface as well. Applications: Measurement of antenna patterns, gain,

and polarization from about 750 MHz to 75 GHz. Any

other application where it is necessary to have a detailed knowledge of electromagnetic field configurations, e.g., scattering experiments.

Availability: To any qualified NBS research workers,

after an initial training period with supervisor. In appropriate instances individual research workers

from other Federal organizations and industry can

gain access to the facility.

Literature:

[1] D. M. Kerns, "Correction of Near-Field Antenna Measurements Made with an Arbitrary But Known Measuring Antenna," Elec- tron. Lett., 6, pp. 346-347, May 1970.

[2] R .C. Baird, A. C. Newell, P. F. Wacker, and

D. M. Kerns, "Recent Experimental Results

in Near-Field Antenna Measurements," Electron. Lett., 6, pp. 349-351, May 1970.

[3] A. C. Newell, and M. L. Crawford, "Planar

Near-Field Measurements on High Perform- ance Array Antennas," Report, National Bureau of Standards NBSIR 74-380, July 1974.

2. Fxtrapolation Range Facilities Capabilities: The Electromagnetics Division operates

two "extrapolation ranges," a 60-meter outdoor

range and a 10-meter indoor range, for performing

high accuracy measurements of gain and polarization

of directive antennas. These ranges each consist of two moveable towers that roll on accurately aligned

rails, enabling one to measure the signal transmitted

between a pair of antennas as the separation distance

between the antennas is varied. Such data are used

to determine the desired far-field (infinite separation

distance) gain and polarization properties of the an- tennas. This method is the most accurate method

known for evaluating directive antennas. Above 1 GHz, the gain accuracy is typically ± 0.08-0.10 dB

and polarization axial ratio can be determined within

± 0.05 dB/dB. Such accuracies are normally not achievable on the best far-field antenna ranges and

the dimensions of an extrapolation range are only

1/5 to 1/10 as large as a far-field range.

Applications: High-accuracy measurements of an- tenna gain and polarization above about 500 MHz

5
with no discernible upper limit. Other microwave

experiments that require the precise motion of a source and/or receiver of electromagnetic energy.

Availability: To any qualified NBS research workers,

after an initial training period with supervisor. In appropriate instances individual research workers from

other Federal organizations and industry can gain access to the facility.

Literature: Accurate Measurement of Antenna Gain and

Polarization at Reduced Distances by an Extra- polation Technique, A. C. Newell, R. C. Baird,

and P. F. Wacker, IEEE Trans. A&P, Vol. AP-21, No. 4, July 1973, pp. 418-431.

Contact: Dr. R. C. Baird, Chief of Fields and Antennas

Section, Radio Building, Room 4085, NBS Boulder,

Colo. 80302, Phone 303-499-1000, ext. 3301.

ROOFTOP ANTENNA

TEST FACILITY

The rooftop antenna test facility is located on the

upper flat portion of the roof above Wing 6 of the

Radio Building.

Capability: This test facility was built to provide a means for measuring antenna reflection and trans- mission coefficients. Two rigid coaxial rf cables

and a multiconductor intercom and power cable connect to the automatic network analyzer in the lab- oratory below. The automatic network analyzer pro- vides for the rf signal generation and detection

requirements.

Applications: Complex reflection (impedance) and

transmission coefficients of antennas can be measured by making use of the automatic network analyzer over the frequency range of 0.1 to 18 GHz.

Antennas can be measured at frequencies below 100

MHz by connecting the lead-in coaxial cables to other rf sources for signal generators and components for signal detection. Although this latter equipment is not presently dedicated for use with the

rooftop antenna range it is available for use from

projects.

Availability: To any qualified NBS research worker,

after an initial training period with supervisor. In appropriate instances individual research workers from

other Federal organizations can gain access to the

facility. Contact: D. H. Russell, Program Chief, Microwave

Measurement Services, Radio Building, Room 4633,

NBS Boulder, Colo. 80302, Phone 303-499-1000, ext. 3811.

BUILDING

RESEARCH

FACILITIES

ACCELERATED WEATHERING LABORATORIES. Compressed

air gun for shooting ice spheres to simulate hail damage

to building materials and systems.

ACCELERATED

WEATHERING

LABORATORIES

The effects of sunlight, rain, hail, atmospheric contaminants, and salt spray are simulated by accelerated

cycling on building materials and systems such as wall coverings and sidings, caulking, roofing, flooring,

paints, and plastic coatings. Seven exposure stations throughout the United States and Puerto Rico provide

a diversity of natural weathering conditions.

Capability: Radiant-energy sources of the accelerated

test machines include single and twin carbon arcs, a fluorescent sunlamp/black-light unit, and both water and air-cooled xenon arcs. Monitoring is by dosi- meters, radiometers, or actinometers. Some machines

have temperature, humidity, and water spray controls, or light/dark cycle controls. A high-humidity chamber is used to subject samples to cycles of water condensation and drying. Flammability of roofing is tested in a small spread-of-flame apparatus. A compressed-air gun fires ice spheres up to IVi inches

diameter against roofing and siding specimens at measured speeds up to 145 feet per second.

6
Applications: Comparative studies of structural materials, coatings, claddings, and composites; identifi- cation of relatively detrimental vi'eathering conditions; research on mechanisms of deterioration;

development of test procedures.

Availability: On contract agreement with other gov- ernment agencies, when equipment is not fully util- ized by NBS research programs. Members of the Section carry out the various tests.

Literature:

[1] L. W. Masters, W. C. Wolfe, W. J. Rossiter,

and J. R. Shaver, State of the Art on Durability Testing of Building Components and

Materials, NBSIR 73-132 (1973).

[2] L. W. Masters and W. C. Wolfe, The Use of Weather and Climatological Data in Evalu- ating the Durability of Building Components

and Materials, NBS Tech. Note 838 (1974). Contact: Robert G. Mathey, Assistant Chief of Materials and Composites Section, Building Research

Building, Room B348, Phone 301-921-3407.

PLUMBING

RESEARCH LABORATORY

With a high-speed, computerized data acquisition

system and hot and cold water supplies with precisely

controlled pressures and temperatures over a wide

range of demands, as well as standard laboratory

fluid services, this laboratory offers unique opportunities to advance the state of the art both in the

design and in the evaluation of plumbing equipment

and systems.

Capabilities: Tests on systems up to 45 ft. in height

and up to 50 ft. in length. Water supply of up to 1000 gpm at constant head in gravity mode; up to 300 gpm in automatically controlled pressure mode

up to 70 psi. Hot water at volumes up to 200 gph at 180°F.

Continuous measurements and recording of rapidly

changing physical parameters such as pressure, dis- charge rate, water depth, and temperature, according

to predetermined criteria, at up to 64 points. Data

analysis through NBS central computer if desired.

Pre-programmed control of experimentation by computer if desired.

Applications: The development of improved criteria for general hydraulic design of and for prediction of loads on plumbing systems; the development of test methodology for calibration and performance eval- uation of innovative plumbing equipment and sys- tems; investigations of performance of piping materials as affected by pressure, flow, and contact with

hot and cold water; methodology for cost effective approaches in needed national programs to update

information on plumbing loads and to develop a modern data bank on performance characteristics of innovative equipment and systems.

Availability: To qualified NBS research workers, after an initial training period. In appropriate instances the

facilities can be utilized by other governmental re- search workers, or by university or industry workers.

Literature:

[1] UA Journal, August 1972, pp. 33-35.

[2] Building Systems Design, May 1972, pp. 50-

54.

[3] Commerce Today, February 21, 1975, pp. 30-

31. Contact: Dr. L. S. Calowin, Chief of the Building

Service Systems, Building Research Building, Room

B306, Phone 301-921-3293.

STRUCTURES

LABORATORIES

Static and dynamic testing is accomplished by use of

a heavily reinforced tie-down floor permitting mounting of complete structural members. Hydraulic actuators provide test loads in static test while closed- loop electro-hydraulic actuators provide test loads in dynamic tests. Automatic recording of up to 200

channels of sensor data is accomplished by a minicomputer-controlled data acquisition system.

Capability: The main test floor of heavily reinforced concrete and imbedded I-beams is 53 X 47 feet in size and is supplemented in the long direction by a 25 foot extension, 20 feet wide, for testing long

beams. The 53-foot section has a 12,000 ft-kip bending moment capacity, and its 25-foot extension has a bending moment capacity of 8,000 ft-kips. The cross- wise section 47 feet in length will withstand a total bending moment of 21,000 ft-kips. The floor will withstand a total horizontal shear force of 1800 kips

in either direction and a vertical shear force of 2,000

kips. It is serviced by two 10-ton bridge cranes having

a clear hook height of 25 feet. The ninety-nine an- chorage tie-down points are designed to withstand

100 kips of either tension force or horizontal shear

force. Six additional points have twice this capacity.

An associated laboratory, 22 X 75 feet, is serviced by

two 2-ton cranes and contains two universal testing

machines of 60,000-lbs, one of 200,000-lbs capacity,

and two compression machines of 300,000-lbs and

600,000-lbs capacity. The 600,000-lb capacity ma7
chine has adequate clearance for testing an 8-ft high,

4-ft wide structural member.

Application: Beams, slabs, frames or complete struc- tures can be subjected to static loads as limited by

test floor capacity or cyclic loads up to 50,000 pounds

with programmed amplitude and frequency. Signals

in the range of 0 to 300 volts from load cells, strain gages, pressure transducers, LVDT's, and other types

of electromechanical sensors are recorded on magnetic tape and optionally printed on teletypewriters.

Two mini-computer controlled data acquisition sys- tems are available. A 200-channel portable system

for either laboratory or field use provides digital re- cording under manual or computer control. Another

112 channels of data may be recorded in digital

form by a laboratory-based system. Its channels may

be accessed in sequence or at random while under

computer control, and manual control is also avail- able. Any 14 of these 112 channels may be used for recording in analog form on magnetic tape.

Software packages are available for processing data

obtained by either of these systems on the central NBS computer. Processing may be controlled through

the use of a laboratory-located remote terminal.

Availability: When not otherwise in use and when

staff is available to prepare the facility for the user.

Literature:

[1] Achenbach, P. B., Building Research at the

National Bureau of Standards, Nat. Bur. Stand. (U.S.) BIdg. Sci. Ser. No. 0 (Oct. 1970).

[2] Yokel, L. Y. and Somes, N. F., Structural Per- formance Evaluation of Innovative Building

Systems, ibid Tech. Note 706 (Aug. 1972).

[3] Yancey, C. W. and Somes, N. F., Structural Tests of a Wood Framed Housing Module,

NBSIR 73-121, NTIS: Com-73-10860, (Mar.

1973). Contact: Dr. R. A. Crist, Chief of Structures Section,

Building Research Building, Room B168, Phone 301-

921-3471.

THERMAL ENGINEERING

LABORATORIES

This group of five laboratories permits performance

testing of refrigeration and air conditioning equipment, heating systems, and insulating materials. Well

controlled conditions of temperature and humidity

are maintained in large test chambers. An analog and

digital data logging system is available for 300 six- digit channels for 0.1 to 1000 volt inputs.

Capabilities: The Air Cleaning Laboratory contains a

test duct capable of maintaining flows of 50 to 2500

cfm through a 2 ft X 2 ft device; also equipment for

particle counting, dust sampling, and NBS dust spot

efficiency. Air cleaners can be tested, anemometer

scans checked, and field evaluation of dust problems

made.

The Air Conditioner and Heat Pump Laboratory in- cludes an indoor room 39 ft X 13 ft X 21 ft, controlled for 40°F to 140°F, and 50% rh at 35''F to 85°F dewpoint at 120"'F; and an outdoor room 20 ft X 13 ft X 21 ft, controlled for —10°F to 150°F.

Heat pumps may be tested in either the winter or the summer mode.

The Environmental Laboratory, 49 ft X 42 ft X 31 ft,

is controlled for —46°C(—50°F) to 66°C(150°F), and

50% rh at 35°F to 85°F dewpoint at 120°F. Supply

air is furnished by ceiling diffusers; damper-controlled air ducts in all eight corners of the room per- mit good air distribution. The floor is earth and may

be excavated. Thermal performance or heating and

cooling load measurements can be made either on models or on full-scale building constructions or equipments.

The Refrigeration Laboratory, 49 ft X 20 X 17 ft, is controlled for —50°F to 150°F, and 50% rh at 35°F

to 85°F dewpoint at 120°F. The ceiling is perforated,

allowing 30,000 cfm of conditioned air through any

or all quadrants. A large door permits access to out- doors, and the floor is concrete with a temperaturecontrolled space underneath. Long-term control of temperature, humidity, and air motion permits development of standard test methods for freezers, coolers, refrigerated spaces or vehicles, heated enclosures,

air conditioning systems or large components, heat- ing systems and large humidifying or dehumidifying

equipments. A small dynamometer has a capacity of 15 hp.

The Thermal Conductivity Laboratory has a very uni- form temperature control; being underground, it is effectively shielded from outdoor temperature variations. Equipment available can take measurements

from —196°C (—320°F) to 1200°C (2200° F) on glass,

ceramics, pure metals or alloys, in air, vacuum, argon,

or helium. The NBS Guarded Hot Plate Apparatus is the standard method of ASTM CI 77 for absolute

determination of the thermal conductivity of dry

specimens of good insulators; its range is 0.1 to 10

Btu per hour ft^ (°F/in.), or 0.15 to 15 milliwatts per cm °C from 0 to 130°F (—18 to 54°C). Recently a new and more accurate hot plate apparatus based

upon the Robinson Line Heat Source concept was added to the conductivity measurement facility.

Availability: To any qualified guest worker, to the

extent consistent with NBS requirements; to other

Government agencies on request.

8
Literature:

[1] Watson, T. W. and Robinson, H. E., Trans. ASME Heat Transfer, 83C, 403 (1961).

[2] Peavy, B. A., J. Res. Nat. Bur. Stand. (U.S.), 67C, (2) 119 (1963).

[3] Hahn, M. H., Robinson, H. E., and Flynn, D.

R., ASTM Spec. Tech. Publ. No. 544, 167-

192 (1974). Contact: Dr. T. Kusuda, Chief of Thermal Engineering Section, Building Research Building, Room B104,

Phone 301-921-3501.

THERMOGRAPHIC

EQUIPMENT

Thermography portrays an object by use of the ther- mal energy emanating from its surface, with instru- mentation resembling a closed-circuit television system. An infrared scanning camera converts invisi- ble infrared radiation (2-5.6/;tm wavelength band) into equivalent electronic video signals. These signals are amplified and transferred by interconnecting

cables to one or more monitoring units. In the primary monitor they are further amplified and used to modulate the intensity of an electron beam to pro- duce a thermal image in which the hotter areas will appear brighter and the cooler areas darker. There

are two secondary monitors, one a color monitor

where different temperature ranges are represented

by different colors, another a profile monitor which

will produce either a contour-like presentation of the

thermal display, or a temperature profile across any

selected scanning line.

Capabilities: The thermographic equipment displays

real-time pictures of the thermal radiation from

either still or moving targets. The scan rate is 16

frames per second, giving a resolving power of 140

standard lines. The object temperature range is from —30°C to +2000°C. The minimum detectable temperature difference is less than 0.2°C at -|-30°C object temperature, increasing to 2% of the temperature range at higher temperatures. Two IR lenses are

available, allowing a range of focus of 0.95m to in- finity with a field of view of 10° X 10° and a range

of focus of 0.6m to infinity with a field of view of 25° X 25°. The equipment requires approximately 2 amperes

using 115V a.c. The output of the photovoltaic indium

antimonide IR detector in the camera is stabilized with liquid nitrogen which also increases the sensitivity. The dewar vessel on the camera will permit 4 hours of operation without interruption.

Applications: Remote scanning of surface temperature measurements of objects in the laboratory or in

the field. Excessive thermal radiation may simply in- dicate insufficient insulation, but more importantly,

may indicate faults in the design or operation of the device or equipment being scanned. Thermography

is especially useful in non-destructive evaluation of thermal equipment in operation, since unsuspected

malfunctions may be responsible for large quantities

of waste heat and inferior products.

Availability: Because of the complexity of the instru- mentation and the procedures of operation, use of

this facility is limited to qualified members of the

NBS staff or other scientists, after specific training of perhaps two months. The facility may be used in- directly through cooperative or contractual research agreements.

Literature:

ri] Applied Optics, Vol. 7, No. 9, September

1968.

[2] Munis, R. H., et al; Detecting Structural Heat

Losses With Mobile Infrared Thermography.

Part I, Description of Technique: Nat. Tech.

Info. Serv., U.S. Dept. Comm., Oct. 1974—

NTIS AD/A-001549.

[3] ibid—Part II, Survey of Pease Air Force

Base, Portsmouth, NH, Corps of Engineers,

U.S. Army, Hanover, NH, CRREL Research

Report 338, June 1975.

[4] Paljik, Ivar, et al; Thermography of Buildings; Scangraf AB Stockholm, 1972. Contact: C. W. Hurley, Mechanical Systems Section,

Building Research Building, Room B126, Phone 301-

921-3741.

9
CALORIMETERS

LOW TEMPERATURE ADIABATIC CALORIMETER. The adiabatic calorimeter with associated cryogenic and vacuum

equipment.

FLUORrNE COMBUSTION

CALORIMETER

Solid samples may be reacted with fluorine gas in a nickel or monel 300 cm^ combustion bomb. Gas

samples may be reacted in a flame (flow calorimeter)

with a monel burner.

Capabilities: Fluorine or other reactive gases are stored in a special hood and are dispensed by a manifold having a pressure range from one pascal

(about 1.3 micrometres of mercury) to three megapascals (about 30 atmospheres). Both the manifold

and calorimeters are located in a second safety hood.

Under optimum conditions, the sample sizes should

be such as to cause 40 kj to be liberated as heat in the reaction. Under these conditions energies or enthalpies of reaction may be determined with a precision of better than 0.02%. Auxiliary equipment

is available to handle and prepare samples.

The combustion vessel is located in a stirred-water

isoperibol calorimeter. The temperature of the calori- meter jacket is held constant to within 0.001 °C. Cal- orimeter temperatures are measured by a quartzoscillator sensor with digital printout. The calorimeter

is calibrated electrically. Reduction of temperaturetime data is carried out by a time-shared computer.

Application: Used to determine enthalpies of reac- tion at or near room temperature, for the purpose of obtaining enthalpies of formation, enthalpies of solution, and related thermodynamic properties of substances.

Availability: Because of the complexity of the instru- mentation and the procedures of operation, use of

this facility is limited to qualified members of the

NBS staff or scientists, after specific training of per- haps two months. The facility may be used indirectly

through cooperative or contractual research agree- ments.

Literature:

[1] R. C. King and C. T. Armstrong, Constant

pressure flame calorimetry with fluorine. II The heat of formation of oxygen to fluoride.

J. Res. Nat. Bur. Stand. 72A, 113 (1967).

[2] E. S. Domalski and G. T. Armstrong, The

heats of combustion of polytetrafluoroethy- lene (Teflon) and graphite in elemental fluorine. J. Res. Nat. Bur. Stand. 71A, 105 (1967). Contact: Dr. C. T. Armstrong, Chief of Thermochemical Measurements and Standards Section, Chemistry

Building, Room B350, Phone 301-921-2131.

LOW TEMPERATURE

ADIABATIC CALORIMETER

This instrument was designed and built at NBS to make high accuracy heat capacity measurement for characterization of the thermodynamic properties of

materials. The instrument is automated for roundthe-clock operation.

Capability: Specimens in solid or liquid state compatible with gold plated copper cell. Temperature

range, 2 to 380 K with ±0.001 K accuracy (referenced

to IPTS 1968). Heat capacity accurate to 0.05%. A

lower accuracy scanning mode is being considered

for alternative operation in the future. Applications: Low temperature thermodynamic properties; glass transition; heats of fusion and transition; comparison of glass and crystal states; zero point

entropies; sensiitve measure of glass transitions using

thermal drifts; detection of small effects of thermal

history.

Availability: Operation under the direct supervision

of Dr. S. S. Chang. Measurements of mutual interest can be arranged with NBS and other government

personnel in accord with agreement.

10
Literature:

[1] K. F. Sterrett et al, An adiabatic calorimeter

for the range 10 to 360 K, J. Res. Nat. Bur. Stand. (U.S.) 69C, 19 (1965).

[2] S. S. Chang and A. B. BestuI, Heat capacities

of Cis-1, 4-polyisoprene from 2 to 360 K,

J. Res. Nat. Bur. Stand, 75A, 113 (1971). Contact: Dr. Martin G. Broadhurst, Chief of the Bulk

Properties Section, Polymer Building, Room B320,

Phone 301-921-2748.

MICROCALORIMETRY

Capability: The facility provides the capability for measuring small thermal power (uncertainty within

±:10/iW) associated with (a) energies of reaction in aqueous solution at 300 K; (b) energies of transition over the range 300 to 470 K; and (c) energies of vaporization from 300 to 470 K. A commercial Calvet- type microcalorimeter and NBS-designed microcalorimeters are available, utilizing the basic principles

of heat conduction microcalorimetry.

A thermopile is used to measure the temperature

difference between the reaction vessel and a heat

sink maintained at constant temperature. Measurement of the emf of the thermoelement as a function

of time yields a measure of the rate of heat exchange.

Resolution of the thermoelement voltage to within a few nV corresponds to a temperature sensitivity of a few tenths of a microdegree. Data are recorded both

in analog and in digital form. For calibration purposes, electrical energy may be introduced with a precision better than 0.01%.

Applications: Many applications are found in the biological sciences where heat, as a totally non-specific

entity, has been found to be a useful tool for studies involving enzyme catalyzed reaction, bacterial metabolism, cellular phenomena, and immunological processes. Since nearly all reactions of biological substances are accompanied by heat effects, microcalorimetry also possesses substantial potential for analytical purposes.

Availability: Because of the complexity of the instru- mentation and the procedures of operation, use of the facility is limited to qualified members of the

NBS staff or other scientists, after specific training of perhaps two months. The facility may be used in- directly through cooperative or contractual research agreements.

Literature:

[1] E. Calvet and H. Prat, "Recent Progress in Microcalorimetry," translated from the

French by H. A. Skinner, The MacMillan

Company, New York, 1963.

[2] "Biochemical Microcalorimetry," H. D. Brown, editor. Academic Press, New York, 1969.

[3] E. J. Prosen, R. N. Goldberg, B. R. Staples,

R. N. Boyd, and G. T. Armstrong. Microcalorimetry applied to biochemical processes,

pp. 253-249 "Thermal Analysis: Comparative

Studies on Materials." H. Kambe and P. D. Garn, editors. (Krdansha Ltd., Tokyo, and

John Wiley & Sons, New York, 1974). Contact: Dr. G. T. Armstrong, Chief, Thermochemical Measurements and Standards Section, Chemistry

Building, Room B350, Phone 301-921-2131.

T,K Typical specific data for different standard reference

materials of polyethylene, using the LOW TEMPERATURE

ADIABATIC CALORIMETER. The second-order glass transi- tion is evident for the sample with the largest around

240 K.

11
PLATINIUM-LINED

ADIABATIC SOLUTION

CALORIMETER

Capability: Liquid or crystalline samples up to 2.7 cm^ in volume are dissolved in 300±15 cm^ of any

solution reactant that does not attack platinum. Minor

modifications permit the introduction of gaseous

samples in a flow system. For exothermic or endothermic reactions of 200 J or more, enthalpies of solution may be measured between 293 and 363 K

for both rapid and slow reactions, with a precision

of 0.02%.

Calorimeter temperatures are measured with a quartzoscillator sensor with digital printout. The adiabatic

shield temperature is controlled automatically to eliminate heat transfer to the calorimeter from its environment. The data are processed by a time-shared

computer. The calorimeter is calibrated by supplying

a known amount of electrical energy to the calori- meter resistance heater before and after the chemical

reaction measurements.

Applications: Used to determine enthalpies of reaction at or near room temperature, for the purpose of obtaining enthalpies of formation, enthalpies of solution, and related thermodynamic properties of substances.

Availability: Because of the complexity of the instru- mentation and the procedures of operation, use of the facility is limited to qualified members of the

NBS staff or other scientists, after specific training of perhaps two months. The facility may be used indirectly through cooperative or contractual research

agreements.

Literature:

[1] E. J. Prosen and M. V. Kilday, An adiabatic

solution calorimeter and measurements of a standard reaction for solution calorimetry,

J. Res. Nat. Bur. Stand. (U.S.) 77A, 179 (1973).

[2] M. V. Kilday and E. J. Prosen, The enthalpy

of solution of low quartz (a-quartz) in aqueous hydrofluoric acid, j. Res. Nat. Bur. Stand.

(U.S.) 77A, 205 (1973). Contact: Dr. G. T. Armstrong, Chief, Thermochemical

Measurements and Standards Section, Chemistry

Building, Room B350, Phone 301-921-2131.

ROTATING

PLATINUM-LINED,

ADIABATIC BOMB

CALORIMETER

Capability: Solid or liquid samples are reacted with

oxygen at three megapascals (about 30 atm) pressure

in a 100 cm^ combustion bomb. The type of sample

is limited only in that the products of the reaction

must not be any chemical species that attacks platinum. A uniform concentration of aqueous products

is assured by continuous rotation of the calorimeter.

Amounts of sample are normally such as to cause 2500 J to be liberated as heat in the reaction. Under

optimum conditions, the energy of reaction can be

determined between 298 K and 323 K with a precision of better than 0.005%. Calorimeter temperatures j are measured potentiometrically with a platinum re- sistance thermometer as the sensor. The adiabatic

shield temperature is controlled automatically to minimize heat transfer to the calorimeter from its environment. Determination of the amount and products of reaction can be determined by measurement

of the amount of CO2 gas formed, and by analysis of aqueous solution constituents.

Applications: Used to determine enthalpies of reac- tion at or near room temperature, for the purpose of obtaining enthalpies of formation, enthalpies of solution, and related thermodynamic properties of substances.

Availability: Because of the complexity of the instru- mentation and the procedures of operation, use of

this facility is limited to qualified members of the

NBS staff or other scientists, after specific training of perhaps two months. The facility may be used in- directly through cooperative or contractual research agreements.

Literature:

[1] W. H. Johnson and E. J. Prosen, The enthalpies of combustion and formation of the

monochlorobenzoic acids, J. Res. Nat. Bur. Stand. (U.S.) 78A, 683 (1974). Contact: Dr. G. T. Armstrong, Chief, Thermochemical

Measurements and Standards Section, Chemistry

Building, Room B350, Phone 301-921-2131.

1 2
COMPUTER

CENTRAL

COMPUTER FACILITIES

The NBS Central Computer Facilities are available on

a fee-for-service basis to support Government pro- grams. In addition to Federal agencies, certain state and local government agencies, non-profit organizations, universities and private organizations, may

qualify for use of the facilities. Service can be pro- vided to non-Federal agencies on joint projects or

for work that cannot be done effectively in the private

sector. Arrangements can often be made to process work through remote terminals.

Facility Overview: The main computer in the NBS

Central Facility is a UNIVAC 1108. The present operating system, EXEC 8, is a general purpose executive designed to operate in a multiprogramming en- vironment which provides for a variety of user options. Access to the main computer is provided to both onsite users and those at remote terminals con- nected via telecommunications. Software support in- cludes FORTRAN, COBOL, ALGOL, XBASIC, MIRADS

(a generalized data base management system), and

OMNITAB (a computer language developed at NBS

for statistical and numerical analysis).

Univac 1108: The UNIVAC 1108 includes 262,144

thirty-six-bit words of 750 nanosecond core memory.

Auxiliary high-speed (1,440,000 characters per sec- ond) drum storage of approximately 25-million characters capacity provides for efficient workload control and swapping of executive program files. Disk

storage of approximately 925-million characters (FASTRAND mode) provides the needed capacity for on-line storage of application programs and data

files. In addition, the system configuration includes

eight seven-track tape drives (200, 556, 800 fpi), two

nine-track NRZI tape drives (800 fpi), two nine-track PE tapedrives (1600 fpi), two printers, two card

punches and two card readers. An IBM 1403-N1

printer is available off-line for printing from magnetic tapes prepared on the 1108.

Grapliics Facilities: The Central Computer Facility

provides off-line plotting on a CalComp 763 ZipMode Digital Plotter, Computer Output to Microfilm

(or hard copy) using a Stromberg-Carlson 4020, and

extended character printing. A Graphical Display System software package is available which permits optical output to a variety of display devices including

the CalComp Plotter, the SC 4020 Microfilm Recorder, or the Line Printer.

Capacity to Handle Scientific Documents: An ex- tended character input/output subsystem, presently

operating off-line to the 1108, permits users to take

full advantage of the information interchange facili- ties of the American National Standard Code for Information Interchange (ASCII). This provides character printing sufficient to handle documents at the normal level of complexity in notation, including

half-line spacing for superscripts and subscripts, a repertory of Greek alphabetic characters and an assortment of special signs and symbols. Off-line paper tape facilities exist for entering ASCII punched

paper tape as data via a 300 CPS optical scan paper

tape reader. Applications and Services: While the primary use of the central computer facility is as a laboratory tool

for the technical staff of NBS and other agencies, an

increasing level of support is provided to a variety of administrative and other data processing applications. A consultant is available during working hours by

phone or in the computer center for advice on details of system operation and problems owing to system

and program interaction. New system development

is frequently done for problem areas of general

utility. Periodic training sessions are heid to acquaint

users with various system capabilities (both hardware

and software).

Literature: Various manuals are available to NBS

users in the storeroom in the Administration Building. Other-agency users may secure manuals through

the Management Assistant's office (301) 921-3364.

Use of Computer Facilities: Charges for the various

computer services are on a cost-reimbursable basis and rate schedules are available.

interested parties may contact Mr. R. A. Palladino,

Management Assistant, Room A225, Administration

Building, NBS, Washington, D.C. 20234 [telephone

(301) 921-3364].

AUTOMATION

LABORATORY

The Automation Laboratory is equipped with a computer controlled robot manipulator system with 6 degrees of freedom and a grip which allows it to pick up objects.

Capability: 750 mm reach; 4.5 kg load, 1 m/sec tip

velocity; touch, force, and proximity sensors. Controlled from a PDP-11/45 minicomputer.

Applications: Research on evaluation of sensors and

computer control techniques for advanced automa13
tion systems such as industrial robots and numerically

controlled machine tools.

Availability: NBS staff, Guest Workers, Research

Associates. Contact: John M. Evans, Jr., Office of Developmental

Automation Control Technology, Technology Building, Room A128, Phone 301-921-2381.

ELECTRICAL

MEASUREMENTS

FACILITIES

NON-MAGNETIC FACILITY. The probe shown in the fore- ground travels along the axis of the 1000-turn precision solenoid to locate the axial position of each turn of wire and to compare the relative area enclosed by each turn. This measurement allows calculation of the magnetic field produced by a known current.

AUTOMATIC

NETWORK ANALYZER

Provides computer controlled rf stimulus for the cali- bration and measurement of passive quantities such

as impedance, reflection coefficient, and attenuation

and active quantities such as power and voltage. This

is a commercially available item which has been

modified into a special high accuracy system by NBS

personnel.

Capability: The automatic network analyzer provides

for discrete frequencies in the range of 0.1 to 18

GHz as an rf stimulus, applies these signals to the

device under test, measures their characteristics,

mathematically manipulates the data if necessary and

outputs the data. The data output is available as a tabulation on a teletype or high-speed printer, a plot or diagram on an electrostatic plotter, or may be

viewed as polar or rectangular plots on an oscillo- scope. The measured data is in complex form and

may be reflection coefficient, impedance, renormalized impedance, VSWR, attenuation, gain, or phase

angle for passive quantities. Data output is in watts,

volts, or fractional (decimal) parts thereof for active

quantities. The connector types for connection to the automatic network analyzer may be in coaxial type such as APC-7, GR-900, type "N" male or female, and in all the waveguide sizes used in the

above frequency range.

These capabilities can be adjusted for either normal

laboratory precision or for high accuracy standards

and calibration type measurements. The NBS add-on

system for high accuracy measurements and calibra- tions is presently undergoing evaluation.

Applications: The automatic network analyzer is in- tended for design, measurement, and calibration of

rf and microwave components such as terminations,

attenuators, thermistor mounts, crystal detectors, FIM

receivers, antennas, filters, amplifiers, transistors, etc. As described previously these may be of coaxial or waveguide type usage devices.

Availability: To any qualified NBS research worker,

after an initial training period with supervisor. In appropriate instances individual research workers

from other Federal organizations can gain access to the facility.

Contact: D. H. Russell, Program Chief, Microwave

Measurement Services, Radio Building, Room 4633,

NBS Boulder, Colo. 80302, Phone 303-499-1000, ext. 3811.

14
ELECTRO-OPTICAL

HIGH VOLTAGE

FIELD MAPPING SYSTEMS

State-of-the-art electrical and electro-optical measure- ment techniques are employed for measurement of high voltages, and for observation and probeless

fringe-pattern mapping of high-intensity electric

fields in insulating dielectrics. Apparatus allows operation under microsecond pulsed, and either steadystate direct or alternating voltages. Unique advantages afforded by the recently developed NBS electrooptical systems include their freedom from electro- magnetic interference errors and their provision for direct visual observations (analogous to those used

conventionally in photoelastic studies of mechanical

stress) of electrical stress distributions.

Capability, Operating Ranges, and Accuracy:

[1] Pulsed Operation: peak voltages from 20 to 300 kV, risetimes of 0.5 to 2.0/j,s, with durations up to 10/iS, repetition to 4 pulses per minute, measurement accuracy within ±1%.

[2] DC Operation: from 0 to 100 kV.

[3] AC Operation: from 0 to 50 kV rms, from

40 to 200 Hz. Programs are available for automatic reduction and

analysis of data, using NBS computer facility. Applications: For calibration of HV pulse-measuring

devices; for design studies with visualization of both

steady-state and dynamic electrical stress distribu- tions in selected insulating dielectrics; for visualiza- tion of the effects of space charge, suspended particles, dissolved ionic impurities and electrode

composition, polish and geometry on electrical conduction in selected insulating liquids; for mapping of

electric field distribution around immersed solid insulator models; for measurement of Kerr electro-optical

coefficients of liquids; for dynamic and steady-state

electrical breakdown studies in selected dielectrics;

etc.

Availability: To qualified U.S. research workers from

industry, government, and academic communities in cooperation with NBS supervisor. Scheduling is re- quired to avoid conflict with in-house NBS research,

calibration and testing programs.

Literature:

[1] NBS Tech. News Bull., Sept. 1972, Vol. 56, pp. 207-209.

[2] Rev. Sci. Instr., June 1972, Vol. 43, pp. 886-

893.

[3] J. Res. NBS, Vol. 73C, pp. 5-13, Jan.-June 1969.

Contact: Dr. Oskars Petersons, Chief, High Voltage

Measurements Section, Metrology Building, Room

B344, Phone 301-921-3121.

NON-MAGNETIC

FACILITY

The non-magnetic building is located on an isolated area of the Bureau grounds, in the center of a 600-ft square buffer zone. The building is a three-story

structure (ground level plus two stories) constructed

of non-magnetic materials and contains a minimum

amount of electrically conducting materials. The

building contains four isolation piers, one serving the

ground floor and three serving the second floor level. A service building 300 ft from the non-magnetic

building provides the general laboratory equipment

and support. Experiments in the non-magnetic building can be controlled and monitored from the service building.

Capability: Typical earth's magnetic field gradients

are 10 nT-m-^ in the vertical direction and 3 nT-m-^

in the horizontal direction. Three-dimensional Helmholtz coils are available for cancelling the earth's magnetic field. Variations in the earth's field can be

reduced by servo-ing to a magnetometer system in the magnetometer station located nearby. A precision

solenoid is available to provide a magnetic field of

1.2 X 10-^ T which is uniform within a 4-cm diameter sphere and accurate to about 0.5 ppm in terms

of the NBS electrical standards. Equipment for auto- mation and data acquisition is available.

Applications: The facilities of the non-magnetic build- ing provide an environment where accurately known

uniform magnetic fields can be applied to an experiment or where the earth's magnetic field strength

and variations can be reduced a known amount.

Currently the gyromagnetic ratio of the proton and

the absolute ampere experiments are housed there.

Availability: The facility is available, when neither of the above two experiments are in active operation,

for a compatible experiment which will not compromise the non-magnetic environment.

Literature:

[1] R. L. Driscoll and P. T. Olsen, The Review of

Scientific Instruments, Vol. 42, No. 10, 1427.

[2] R. L. Driscoll and P. T. Olsen, Proc. of the

International Conf. on Precision Measurement and Fundamental Constants, NBS Special Publ. 343, 117 (1970).

15
[3] B. N. Taylor, D. N. Langenberg, and W. H.

Parker, Scientific American, Vol. 223, No. 4, 62 (1970). Contact: Dr. E. R. Williams, Absolute Electrical Measurements Section, Metrology Building, Room A247,

Phone 301-921-3806.

REACTANCE BRIDGE

FOR POWER LOSS

MEASUREMENT

A typical high voltage inductor or shunt reactor on a power transmission lines has a reactive power rating of 100 megavolt-amperes and a power loss of about

200 kilowatts. Thus the power losses are of economic

significance, but it is difficult if not impossible to measure them by conventional wattmeter methods

because of the low power factor, i.e. the presence of very large reactive or circulating power. The shunt

reactors are used to "tune out" the capacitances of transmission lines. A reactance bridge has been developed and constructed which in conjunction with

readily available high-voltage standard capacitors can measure accurately such losses. Inductance and ca- pacitance can also be measured. The instrument is designed for measurement of devices rated at moderate to extra high voltages—several hundred volts to one megavolt.

Capability: The instrument can be used at either the

NBS or a commercially available high voltage laboratory. The voltage and power ranges depend principally on the capability of the power supply in the

laboratory—for the NBS laboratory these are 220 kV,

200 kVA. Some commercial laboratories have capabilities of the order of 1 MV and 100 MVA. When

used in conjunction with a typical high voltage stand- ard capacitor having a capacitance value of 100 pF,

the inductance range of the specimen is from 0.12 H

to 600 H; the range for capacitors is from 100 pF to

50juF. The power losses can be measured to about

one-percent accuracy; the inductance and capaci- tance to about 0.01 percent to 0.1 percent accuracy. Applications: Primarily power loss measurements of

large capacitors and inductors such as energy storage

and power factor correction capacitors, high voltage

shunt reactors (inductors); also impedance measure- ments of the same.

Availability: To any qualified NBS research worker or group. The High Voltage Measurements Section will provide an operator of the instrument and high

voltage power supplies.

The use of the instrument is also available to outside

groups in the form of calibration and test services. Literature: NBS Tech. News Bull., April 1973, Vol. 57, No. 4, page 91. Contact: Dr. Oskars Petersons, Chief of High Voltage

Measurements Section, Metrology Building, Room

B344, Phone: 301-921-3121.

ELECTRON

MICROSCOPES

Fracture surface on worn steel specimen, including wear

debris. The large depth of focus of the SCANNING ELEC- TRON MICROSCOPE is demonstrated in this photomicrograph.

SCANNING ELECTRON

MICROSCOPE

With resolution and depth of focus well beyond that of optical microscopes, this device uses a fine elec- tron-beam probe to explore the minutiae of surface

structure of materials such as lunar rocks, bridge

structure fractures, microelectronic circuits, and dental restorations. For rough specimens, stereo-pair

photography permits three-dimensional examination.

Selected area electron channelling patterns can be

obtained, and divergent-beam x-ray (Kossel) patterns

16
can be prepared for use in determining local stress- strain configurations.

Capability: Replica or actual specimen up to 2.5 cm

diameter and 1 cm thick. Resolution of 25nm, and

maximum magnification of lOO.OOOx. Electron beam

of about 10 nm (100A) diameter is driven across specimen, while secondary electrons, backscattered

electrons, and x-rays are each detected and amplified

to modify the brightness of a CRT raster. A data

acquisition system and data reduction programs are

available. Applications: Behavior of grain boundaries in embrittled copper-palladium welds; checking of resolution using dendrites of aluminum-tungsten; identifi- cation of material in micrometeoritic lunar craters; distinguishing chrysotile from termolite; qualitative

chemical analysis of microscopic particles; effect of polishing on dental materials; rusting through pinholes in enameled steel; bonding and defects in microcircuitry wafers; hydrogel coating on aortic catheters; wear of currency papers; sharpness of tungsten field-emitter tip.

Availability: To any qualified NBS research worker,

after an initial training period. Over 30 NBS scientists have become competent operators. In appropriate

instances individual research workers from other

Federal organizations can gain access to the facility.

Literature: NBS Tech. News Bull., March 1972, Vol.

56, No. 3, pages 60-63. Contact: Dr. Arthur W. Ruff, Jr., Chief of Microstructures Characterization Section, Materials Building,

Room B118, Phone 301-921-2991.

This facilitates specimen preparation, increases foil rigidity, and reduces surface effects.

Capability: Accelerating voltages of 50, 100, 150, and

200 kV. Selected area electron diffraction and elecro- magnetic beam tilting (±3°) for dark field imaging.

Side entry goniometer stage with: double-tilt (X =

±60°, Y = ±45°), rotation (360°)—tilt (±60 ), and

heating (to 1000° C) —tilt specimen holders for speci- mens up to 3.05 mm in diameter. Resolution (line) of

' o 0.7 nm (7 A) and maximum magnification of 150,000x. Data recorded on 3V4 X 4 inch glass photographic

plates. Dispersive x-ray energy analysis.

Applications: Examination of the surface regions of various ceramic materials after abrasive, smoothsliding and erosive wear; analysis of deformation and

fracture mechanisms in ceramics as a function of temperature; analysis of cracks and crack healing processes in ceramics; microstructure characterization of cemented carbides; determination of stacking fault energy as a function of temperature in Ag-Sn and

Au-Sn alloys; analysis of deformation modes in superplastic Al-base alloys; study of deformation and

corrosion in Cu-, Fe-, and Ni-base alloys.

Availability: To experienced electron microscopists

having research applications which require high volt- age electron microscopy.

Contact: Dr. Bernard J. Hockey, Physical Properties

Section, Materials Building, Room A355, Phone 301-

921-2901.

TRANSMISSION

ELECTRON MICROSCOPE,

200 kV

This instrument allows high resolution examination of surface replicas and actual, thin-foil specimens of metals, ceramics, and polymers. Analysis of microstructure and lattice defects in crystalline materials can be made by electron diffraction contrast and

selected area electron diffraction. The instrument is also equipped with a dispersive x-ray energy analysis

system for elemental analysis. Compared to conventional transmission electron microscopes (100 kV),

specimens which are 70% thicker can be examined.

17
ENVIRONMENTAL

FACILITIES

Portable system for field testing of chlorine-polluted water. Detection and calibration unit of CHLORINE FLUX MONITOR at left, reagent supply unit at right.

CHLORINE FLUX

MONITOR

This newly developed electrochemical system for measuring traces of chlorine in water is based on the

well-known principle that chlorine, chloramines, and

hypochlorites will oxidize an iodide to iodine at the

proper pH. A motor-driven pump supplies the water sample to the iodine detector cell at a constant flow

rate. The cell contains a platinum microelectrode and

a reference electrode with a microammeter connected across them. The ammeter reading resulting

from the oxidation reaction is displayed or recorded

continuously as the monitored signal. A novel feature

is the calibration of the amperometric signal, which

is accomplished internally by supplying an accurately

known amount of iodine generated coulometrically.

Capability: The newly developed chlorine flux monitor is capable of measuring chlorine concentrations

from 20 parts per million (or higher, but higher concentrations were not tested) down to a fraction of a

part per billion. The response is linear over this wide

range (four orders of magnitude) with very few possible interferences, such as ozone, MnOj, Cr207=,

Bro, and lo.

Applications: Measurement of total residual chlorine

concentrations in waste water, reactor coolant water,

power plants, potable water, etc.

Availability: To any qualified researcher whose inter- ests in chlorine measurements parallel those of Dr. George Marinenko and who is willing to collaborate.

Literature:

[1] Dimensions NBS, 58, No. 9, 208-209 (1974).

[2] Patent Application No. 610711.

[3] G. Marinenko, Fisheries Research Board of Canada (in press). Contact: Dr. George Marinenko, Research Chemist,

Analytical Chemistry Division, Chemistry Building,

Room A225, Phone 301-921-2883.

PRECISION

HUMIDITY MEASUREMENT

This facility comprises two precision humidity generators and a gravimetric hygrometer that can be used

separately or in combination for calibration, testing,

and development of instruments, sensors and devices

and for research on the properties of moist gases. The

generators produce continuous gas flows of constant moisture content whereas the hygrometer makes

accurate humidity measurements.

Capability: Gas flows up to 150 cubic decimetres per minute. Ambient temperatures from -|-65 to —75°C.

Mixing ratios from about 150 to 1 X 50"^ g/kg (1.5 X 105 to 0.01 ppm). Dew point of +65°C to frost point of —100°C. Ambient pressures from atmospheric to 50 mb. Generated moisture contents known

to 0.5 percent or better over most of range and to 2 percent at extremes. Measurement accuracy 0.1 percent. New equipment soon operational will pro- vide improved accuracy over wider ranges. Limited

capability for response time testing. Data acquisition

system available. Applications: Calibration of dew-point hygrometers,

psychrometers, electric hygrometers, infra-red hygrometers, dewcels, coulometric hygrometers; eval- uation and testing of such sensors as carbon film,

aluminum oxide, crystal array, lithium chloride, ba- rium floride; enhancement of water vapor in air with

pressure.

Availability: Facility available for use on tests, re- search or programs of NBS divisions, other Government agencies, and industrial or scientific laboratories.

Literature:

[1] J. Res. NBS 40, 479 (1948)

[2] NBS Monograph 73 (1964)

[3] ISA Trans. 7 (No. 4), 356-362 (1969)

18
Contact: Arnold Wexler, Chief, Humidity Section.

Physics Building, Room B356, Phone 301-921-2794.

FIRE RESEARCH

FIRE RESEARCH

LABORATORY

A special laboratory building for large scale fire ex- periments has just been completed.

Capability: A major feature of the building is a 60 ft X 120 ft test floor with a 32 ft ceiling height. The

test floor is equipped with smoke abatement equipment to meet air pollution regulations, water supplies

and floor drains, making it suitable for a variety of

fire experiments. A shop for the fabrication of test structures, a conditioning room for the storage of materials and test structures prior to test, an instru- ment room, and office and service areas complete the

building.

The only permanent experimental facility on the test floor is the Fire Research Test Furnace described in detail below. Other test structures and apparatus are erected as needed for specific programs, providing

maximum flexibility in space utilization. The facilities are: A room and corridor facility. This

consists of a corridor approximately 50 ft long with

two 8 ft by 8 ft rooms opening onto the side wall. Provisions are made for varying the wall and ceiling

spacings and controlling draft conditions. The facility can be used for study of the spread of fire through

corridors, the movement of smoke and gas through

room-corridor systems, the effect of surface finishing

materials on fire spread, and related purposes. A burn room and smoke movement facility. This is a two story masonry structure with controlled ventila- tion and communication between floors. It can be

used to conduct studies of the burning of room furnishings or to study the spread of smoke, gas, and fire through a multi-compartment structure. A rate of heat release calorimeter. This instrument measures the rate of heat release and the total heat

release from a large sample of material when exposed

to a controlled energy flux. It is used to measure the

energy contribution of materials involved in a build- ing fire. A research test furnace. This is a medium-sized unit providing conformity with the temperature-time ex- posure specification of ASTM El 19, plus extension to

150%. It will accommodate 30-ton walls or partitions

10 feet long by 8 feet high, 20-ton columns 8 feet high, or 20-ton floor-ceiling assemblies 8 feet by 10

feet. Furnace pressure is controllable between —0.05 and -|-0.15 in. water to permit study of the effect on

fire performance. The furnace can be used for fire endurance tests on structural components such as ducts, dampers, doors, and plumbing systems, on

innovative constructions such as double modular

walls, and on joints in wall-floor assemblies.

Applications: The Fire Research Laboratory provides

a location where large scale fire experiments can be

carried out under controlled conditions. Space is available for the construction of a variety of experimental installations.

Availability: Available upon request for research ex- periments for other Government agencies and industrial groups. Available for research programs of in- dustrial Research Associates. Availability of specific

facilities is dependent on workload.

Literature:

[1] Francis C. W. Fung, Miles R. Suchomel and

Philip L. Oglesby, The NBS Program on Corridor Fires, Fire journal 67, pages 41-48 (May

1973).

[2] W. J. Parker and M. E. Long, Development

of a Heat Release Rate Calorimeter at NBS,

ASTM STP 502, pages 135-151 (1972). Contact: Mr. J. A. Benjamin, Fire Technology Division,

Technology Building, Room B64, Phone 301-921-

3255.

A room fire test in the FIRE RESEARCH LABORATORY.

19
HIGH PRESSURE

FACILITIES

HIGH PRESSURE PVT DILATOMETER. The mercury column

is seen In the capillary inside the pressure chamber.

HIGH PRESSURE

GENERATORS

Two systems for generating high pressures have been

developed for the measurement of electrical, mechanical and pressure/volume properties of liquids

and solids. Capability

System 1 System II MAXIMUM 26 kbar 40 kbar PRESSURE 2600 (MPa) (4000 Mpa)

USABLE 19mm diameter 10mm diameter

VOLUME X 100mm length X 10mm diameter

ELECTRICAL 4 1 LEADS

PRESSURE manganin ram force GAGE

TRANSMITTING pentane mixtures pentane mixtures. FLUID also soft solids

Application: System 1 has been used for ultrasonic measurements on solids and liquids, for electrical resistance measurements, for measurements of crack

propagation in glasses and for the study of phase

transition. Apparatus requiring electrical leads can be

plugged into a receptacle at the inside bottom of the

pressure vessel. A total of four leads are available. System II has been used for ultrasonic measurements

in liquids and in solids under either hydrostatic or non-hydrostatic conditions. Transducers to detect

shear or longitudinal mode properties are mounted

on the outside; they use a back plate as acoustic

buffer. A back plate with one electrical lead is also

available.

Availability: The equipment is available to qualified

researchers after an initial training period or with

assistance from Section personnel.

Literature: D. L. Decker et al, High-Pressure Calibration, A Critical Review, J. Phys. & Chem. Ref. Data,

1, no. 3, pp. 173-836, 1972. Contact: Dr. Peter L. M. Heydemann, Chief, Pressure and Vacuum Section, Metrology Building, Room

A149, phone 301-921-2121.

HIGH PRESSURE

OPTICAL

FLUORESCENCE SYSTEM

The optical system measures the pressure-dependent

shift of the sharp fluorescent R^-line of ruby which

has been calibrated against the compression of NaCI

as the primary standard. The system was developed

to measure pressure in the diamond-anvil high pres- sure cell, but with minor modification can be used in any pressure vessel which has optical access.

Capability: Quantitative pressure determinations are made to 300 kbar with an accuracy in the range of 5 percent; qualitative measurements up to the realiz- able limit of about 500 kbar. Temperature capability to 300°C is also available, but the accuracy in the pressure measurement is significantly reduced at this temperature.

Applications: Characterization of phenomena in- duced by pressure—such as phase transitions in solids, freezing pressures of liquids, glass transition pressures in vitrified materials, compressibility measurements (in conjunction with x-ray measurement),

and pressure distribution in various pressure trans- mitting media.

Availability: On a selective basis when not required

for Crystallography Section programs. The system

20
must be operated by Section personnel and only

work of mutual interest can be unde taken.

Literature:

[1] C. J. Piermarini, S. Block, J. D. Barnett, and

R. A. Forman, J. Appl. Phys. 46, 2774 (1975).

[2] C. J. Piermarini and S. Block, Rev. Sci. Instr. 46, 33 (1975). Contact: Dr. C. J. Piermarini, Materials Building,

Room B224, Phone 301-921-2950,

HIGH PRESSURE

PVT DILATOMETER

This PVT (pressure-volume-temperature) apparatus is used to measure the density of liquids and solids (including polymers) with varying temperature and

pressure. The method employs pressurized dila- tometry in which a dilatometer is placed in a pressure chamber with glass windows. This chamber is, in turn, placed in a liquid thermostat with glass windows which is controlled by a refrigerator and electric heaters. The pressure is generated by a hand

pump and may be determined by a bourdon or dead

weight piston gage. The sample volume is determined

in terms of the relative height of the mercury col- umn of the dilatometer, using a cathetometer.

Capability: Temperature range, —40 to 200°C. Constant heating and cooling rates may be selected as low as .05°/hr; pressure range, 800 bar. (This range may be extended to 2 kbar by using a suitable pres- sure chamber.) A dead weight piston gage is available

to maintain constant pressure during, for example,

isobaric heating and cooling, and volume creep

measurements.

Applications: Ordinary equilibrium PVT measurements, including phase changes. Non-equilibrium

measurements may include influence of temperature

and pressure on glass transition and crystal growth

mechanisms, glasses formed at constant volume, and

volume creep and stress (pressure) relaxation. The

densification of polymer glasses at elevated formation

pressures gives a higher refractive index which suggests their use as optical lenses.

Availability: By research workers on problems of mutual interest with those of the Bulk Properties

Section. Initial instruction will be given by the Section

staff.

Literature:

[1] J. E. McKinney and R. W. Penn, Rev. Sci.

Instr. 43, 1212;

[2] J. E. McKinney and M. Goldstein, J. Res.,

Nat. Bur. Stand. (U.S.) 78A, no. 3, 331-353

(May-June 1974). Contact: John E. McKinney, Bulk Properties Section,

Polymer Building, Room B330, Phone 301-921-2116.

HIGH TEMPERATURE

FACILITIES

Levitation vacuum melting equipment for preparation

of high-purity materials in the ALLOY PREPARATION

LABORATORY.

ALLOY PREPARATION

LABORATORY

Research grade samples of metals and alloys are pre- pared when such samples are not readily available commercially, or when accurate details are required

concerning the purity of the constituents and the melting and fabricating history.

Capability: Vacuum-induction melting and casting; arc furnace; levitation melting furnace; electron- beam zone refiner; electron-beam button meiter;

electron-beam evaporator; induction and resistance melting and casting furnaces; heat-treating furnaces; cold-working equipment for rolling, swaging, and

drawing; apparatus for producing metallic hydrides

under hydrogen pressures up to 6900 kN/m- (1000

psi). Applications: High purity iron ingot with 1.194

±0.004% carbon; homogeneous ingot of magnesium-zinc; 200-mesh lead-indium powders; devices

for hydrogen storage.

21
Literature: NBS Tech. News. Bull. Vol. 56 No. 8, p. 182-183 (Aug. 1972). Contact: H. C. Burnett, Scientific Assistant, Metallurgy

Division, Materials Building, Room B260, Phone 301-

921-2813.

Schematic of the HIGH TEMPERATURE CONTROLLEDATMOSPHERE FURNACE, designed for testing thermocouples in high temperature gas environments.

HIGH-TEMPERATURE

CONTROLLED-ATMOSPHERE

FURNACE

The furnace provides the facility for establishing

heated environments at a temperature in the range

between 1000°C and 2750°C in vacuum. If high conductivity gas environments are required the upper

temperature range is about 2500°C.

Capability: The furnace has a tungsten-mesh heating

element 6.4 cm in diameter by 30.5 cm long, oriented

with its central axis vertical. The heating element is surrounded by tungsten radiation shields formed

from 0.125 mm thicl< tungsten sheet; these are en- closed within a water-cooled copper assembly. A 10- cm diameter port at the top of the vacuum chamber

provides complete access to the interior of the heating element for installing materials and experimental

devices for test. A viewing port on the side of the vacuum chamber is part of the optical path that extends to within the heater coil. At ambient temperatures, base pressures of less than 5 X 10~" torr (6.66 nNm--') may be achieved within 20 hours and

the furnace is designed to produce hot zone temperatures to 3000 K while maintaining the pressure in the

10-* torr (1333 nNm--) range. Equipment conventionally used with the furnace includes a residual gas analyzer and a photoelectric pyrometer.

Applications: Thus far the furnace has been used for investigating the behavior—stability and emf characteristics—of tungsten/rhenium alloy thermocouples.

Availability: To any qualified NBS research worker,

after making availability arrangements and receiving

training from Mr. George Burns, phone 301-921-2069.

In appropriate instances arrangements might be made

for individual research workers from other Federal organizations to gain access to the facility. The fur- nace is currently in use for research over extended

periods of time.

Literature: J. Res. Nat. Bur. Stand. (U.S.) Vol. 75C, No. 2, April-June 1971. Contact: Dr. J. F. Schooley, Chief, Temperature Section, Physics Building, Room B222, Phone 301-921-

2801.

HIGH TEMPERATURE

VAPORIZATION

LABORATORY

This laboratory contains extensive facilities for the

study of high-temperature vaporization equilibria and

gas phase chemical reactions.

Capabilities: The laboratory is equipped to carry out measurements of vaporization equilibria at temperatures up to 3200K using both Langmuir and Knudsen

methods. The laboratory is equipped for mass spectrometry, torsion effusion, and gravimetric (including vacuum microbalance) methods. A unique mass spectrometric sampling system has been developed to permit molecular beam sampling from high temperature gaseous or gas-solid systems at pressures exceeding one atmosphere, and other mass spectro- meters are available for the study of heterogeneous

reactions of solids with reactive gases at high temperatures. Applications: The facilities of the laboratory have

been or are being applied to investigation of a number of diverse high-temperature problems. These in- clude measurements of vapor pressures and v^oorization thermodynamics for metals, oxides, carbides, and

other materials, as well as vapor-solid reaction studies

related to the corrosion of refractories in aggressive

environments. Investigations involving sampling of

specific regions of flames are carried out to define

basic flame chemistry and to study effects of flame

extinguishants and retardants at the molecular level.

22
Other applications include investigations of laser- induced chemical phenomena in the gas phase.

Availability: Because of the complexity of the instru- mentation and prior programmatic commitments,

direct use of the facility is limited to qualified members of the Section staff. The facility may be used

indirectly through collaborative research agreements

with other qualified NBS or guest scientists.

Literature: NBS Tech. News Bull. 56, 11, 271, January

1972. Contact: Dr. T. D. Coyie, Chief, Inorganic Chemistry

Section, Materials Building, Room A329, Phone 301-

921-2847.

INORGANIC GLASSES:

PREPARATION AND

VISCOSITY

This laboratory has facilities for the melting of experimental glasses at temperatures to 1600°C and for measuring the viscosity of glasses over the range from 102 to 1015 poises (10 to 10^* Pa-s) at temperatures 1430 to 520°C.

Capabilities: A batch of lOOOg of an experimental

glass can be made using starting materials of known

purity and doped with known amounts of trace ele- ments. The melts are normally made in platinum

crucibles heated in an electric furnace with silicon carbide elements, and stirred with platinum-10%

rhodium stirrers to produce glasses having a high

degree of homogeneity. Melts may also be made in ceramic crucibles if the glass composition is not compatible with platinum. After fining the molten glass is poured into a metal mold to form a test block, which

is then placed in a muffle furnace to cool to room

temperature in about 18 hours. From this block samples may be cut for property measurements. Speci- mens may also be cast into various shapes or drawn

into rods, tubes, or fibers. Viscosities in the range of 10- to 10^" poises (10 to 10^ Pa-s) corresponding to a temperature range for soda-lime-silica glass from 1430 to 630°C, are measured by a rotating concentric cylinder apparatus.

Higher viscosities, up to 10'-'' poises (10" Pa-s) at temperatures down to about 520°C for the sodalime-silica glass, are measured primarily by fiber elongation procedures.

Applications: Production of small lots of optical glass.

Synthesis of the glassy coal slag produced in magneto-hydrodynamic power cells, and measurement of

its properties. Studies of softening, annealing, and

strain points needed for control of viscosity in automatic machinery used to manufacture glass containers.

Availability: Because of the experience required, the use of the laboratory is limited to (a) permanent

members of the Section and (b) qualified individuals working directly under the supervision of Inorganic

Glass Section personnel. The facility may be used

indirectly through cooperative or contractual research agreements.

Literature:

[1] Given W. Cleek and Edgar Hamilton, Properties of Barium Titanium Silicate Glasses,

J. Res. Nat. Bur. Stand. (U.S.) 57 [6] 317

(1956).

[2] Albert Napolitano and Earl G. Hawkins, Vis- cosity of a Standard Soda-Lime-Silica Glass,

j. Res. Nat. Bur. Stand. (U.S.) 68A [5] 439

(1964).

[3] Albert Napolitano, Pedro B. Macedo, and

Earl G. Hawkins, A Wide-Range (up to lO^^P)

Rotating Cylinder Viscometer, J. Res. Nat.

Bur. Stand. (U.S.) 69A [5] 449 (1965). Contact: Dr. W. Haller, Chief of Inorganic Glass Section, Inorganic Materials Division, Materials Building,

Room B328, Phone 301-921-2819.

LASER MATERIALS

FACILITY

This well-characterized, high-power laser of neodymium-doped glass is used to produce data on the damage thresholds for laser materials.

Capability: The neodyminum-doped glass laser consists of an oscillator and two amplifiers. The temporal

and spatial properties of the laser beam are well controlled and characterized with precision. The oscil- lator operates in the TEMoo mode with an aperture of about 2.5 mm in diameter. The spatial beam profile

at 5 m from the output energy approximates a Gaussian distribution. The output energy is reproducible

to within ±2%. The facility with one amplifier pro- duces a minimum energy of 650 mj. The facility with

both amplifiers produces approximately 3 J with some

deterioration of the beam quality.

The operating pulse width at half the maximum

power and the wavelength are respectively 25 ns and

1060 nm. A frequency doubler is available to produce

a 530 nm wavelength. A laser-triggered spark gap

and Pockels cell are available for producing pulse

widths as small as 2.5 ns. A dye cell is available for mode-locking.

23
Applications: This facility is used to measure extrinsic and intrinsic bulk damage thresholds and surface damage thresholds. Whenever intrinsic damage arises from self-focusing, procedures exist for the identifica- tion of the dominant mechanisms, such as the ther- mal effect, electrorestrictive effect, and Kerr effect. The facility also may be used to investigate two- photon absorption processes.

Availability: The availability of this facility depends

upon mutual interest, the time required to make the

measurements, and whether there are other commitments for its use. Because this facility is complex,

its use requires the presence and guidance of permanent members of the laboratory. A requesting party,

who is qualified, may assist in taking the data.

Literature:

[1] A. Feldman et al., ARPA-NBS Program of Research on High Temperature and Laser Materials, NBS Technical Note 703 (Dec. 1971).

[2] A. Feldman et al., "Mechanisms for Self- Focusing in Optical Glasses," IEEE Journal of Quantum Electronics (Nov. 1973). Contact: Dr. Herbert S. Bennett, Chief of the Solid

State Materials Section, Room A259, Materials Building, Phone 301-921-2415.

MILLISECOND

HIGH-TEMPERATURE

THERMOPHYSICAL

MEASUREMENTS

This facility, which is unique of its kind in the world,

allows the accurate measurement of selected thermophysical and related properties of electrically conducting solid substances at high temperatures (above

1500 K) in experiments of subsecond duration.

Capability: The method is based on rapid resistive self-heating of the specimen from room temperature

to any desired high temperature (up to the melting

point) in less than one second by the passage through

it of electrical currents of several thousand amperes.

Measurement and recording of experimental quantities are made automatically every 0.4 millisecond,

with a full-scale signal resolution of one part in 8000.

A high-speed pyrometer and a digital data acquisition system are employed.

Applications: The facility provides the capability of measuring, either simultaneously or consecutively,

the following properties: specific heat, electrical resistivity, hemispherical total emittance, normal spectral emittance (at 650 nm), and melting point, in the

temperature range from 1500 K to the melting point

of the specimen. The facility, after some modifications, has the potential of measuring other thermodynamic and transport properties and extending the

measurements to the liquid phase.

Availability: Because of the complexity of instrumentation, the direct use of this facility is limited to: (a) permanent members of the laboratory, and (b) qualified full-time guest scientists with appointments ex- ceeding six months. The facility may be used indirectly through cooperative research agreements.

Literature:

[1] A. Cezairliyan, M. S. Morse, H. A. Berman,

and C. W. Beckett, J. Res. Nat. Bur. Stand.

(U.S.), 74A, 65 (1970).

[2] A. Cezairliyan, J. Res. Nat. Bur. Stand. (U.S.), 75C, 7 (1971). Contact: Dr. Ared Cezairliyan, High-Speed Thermophysics Laboratory, Hazards Building, Room 124,

Phone 301-921-3687.

LOW PRESSURE

FACILITY

MERCURY MANOMETER

For this design of low-pressure manometer, end

length standards are used to measure the height of the column of mercury that is supported by gas pressure. The locations of the large mercury menisci are reproduced by reestablishing the capacitance between the crowns and carefully located capacitance

electrodes.

Capability: Optimum relative accuracy of a single pressure measurement within 2 X 10"" for pressures between 5 X 10=* and 1 .3 X 10^ Pa (4 cm to 1 m Hg),

and for ratios of pressures that are in the same range. The relative error for lower pressures does not exceed

5X10" for pressures down to 5 X 10^ Pa (0.4 cm

Hg). Both absolute and differential pressures can be

measured.

Applications: Determination of the pressure of fixed points for "benchmark" purposes; realization of a standard atmosphere; calibration of highest quality

deadweight gages operating in the range of 1 atmosphere; calibration of ultraprecise manometers (such

as ultrasonic mercury manometers, and perhaps dia- phragm or quartz devices).

24
Availability: On a selective basis when not being

used for gas thermometry. It is desired to make use

of the facility so far as possible whenever the exceptional accuracy obtainable is essential. The instru- ment must be operated by project personnel.

Literature:

[1] Metrologia 6, 1 (1970).

[2] NBS Tech. News Bull., March 1971, Vol. 55, No. 3, pages 73-75.

[3] Experimental Thermodynamics, v. II, Ch. 4., pt 1, 115-131 (1975). Contact: Dr. Leslie A. Cuildner, Project Leader, Gas

Thermometry, Room A05, Physics Building, Phone

301-921-2076.

LIQUEFIED NATURAL GAS FLOW FACILITY. Insulated tanks with pumps, weighing system, and instrumentation for liquefied natural gas. LOW TEMPERATURE

FACILITIES

ACOUSTICAL

THERMOMETER

The instrument is a standing wave ultrasonic inter- ferometer that operates at principally 1 megahertz. It

is employed to determine values of temperature between 2 and 27 kelvins on the NBS P2-20 (1965)

scale.

Capability: The instrument employs highly reproducible germanium resistance thermometers for indi- cating the constancy and reproducibility of temperatures. Isotherms of the speed of sound versus the

pressure of 'He gas have indicated a reproducibility

of data points that is within ±2 millikelvins. The

facility has operated at temperatures between 2.3 K and 27 K. A laser interferometer has been installed to permit the measurement of acoustical wavelengths.

Auxiliary equipment permits the potentiometric

measurement and calibration of the resistance of germanium resistance thermometers.

Applications: Determination of absolute temperature

values at low temperatures.

Availability: This facility is available at times when it

is not being employed for the Temperature Section's research program.

Literature:

[1] Metrologia, Vol. 2, No. 4, 18 (1966).

[2] Cataland, C. and Plumb, H. H., Nat. Bur. Stand. (U.S.), Tech. Note 765, 23p (May

1973). Contact: Dr. J. F. Schooley, Chief, Temperature Section, Physics Building, Room B222, Phone 301-921-

2801.

CRYOGENIC FLOW

RESEARCH FACILITY

Facility provides continuous flow of liquid nitrogen

with the ability to control flow rate, temperature,

and pressure over wide ranges.

Capability: Flow rate is continuously variable for 1.3 to 13X^s (20 to 200 gpm). Normal temperature range

is 72 to 90 K (129.6 to 162°R) which can be extended

to 115 K (207°R). Normal pressure range is 0.22 to 0.77 MPa (32 to 112 psia) which can be extended to 2.15 MPa (312 psia). Temperature and pressure combinations are limited to the compressed liquid region

for accurate flow rate determinations.

Applications: Flow measurement; heat transfer measurements in flowing fluids at cryogenic temperatures;

calibration of flowmeters and transfer devices.

Availability: To qualified NBS and other Federal Government personnel. Facility operators will be provided.

Literature:

[1] J. A. Brennan, et al.. Tech. Note 624, "And

Evaluation of Several Cryogenic Turbine

25
Flowmeters," Nat. Bur. Stand. (U.S.), Oct. 1972.

[2] J. A. Brennan, et al, "An Evaluation of Selected Angular Momentum, Vortex Shedding

and Orifice Cryogenic Flowmeters," NBS

Technical Note 650 (March 1974).

[3] J. A. Brennan, et al, "NBS-CCA Cryogenic

Flow Measurement Program," ISA preprint

74-612, ISA Annual Meeting, Oct. 28-31,

1974. Contact: R. S. Collier, Chief, Cryogenic Metrology

Section, Cryogenics Building, Room 1108, NBS

Boulder, Colo. 80302, Phone 303-499-1000 ext. 3178.

HYDROGEN LIQUEFACTrON

FACILITY

The NBS hydrogen liquefier was first operated in March 1952. Since that time it has been used extensively as a liquefier and as a general facility for rel- atively large-scale low-temperature experiments re- quiring quantities of high pressure gas and purifica- tion equipment.

Capabilities: The facility contains compressors, vac- uum pumps, gas holders, liquid nitrogen temperature

silica gel purifiers and a liquefier containing an ortho

to para hydrogen catalyst. The unit is capable of producing liquid hydrogen at the rate of 250 liters per hour. The gas flow rate is 750 standard cubic feet per minute (1300 mVh) at approximately 2000 psi

(13.6 X lO^Pa). The purifiers and the liquefier proper

are contained in stainless steel high-vacuum insulated

dewars 30 inches diameter by 93 inches long (0.76 m

X 2.4 m).

Applications: The facility is applicable to large scale experiments requiring low temperatures combined

with a gas flow and purification capability. Safety

equipment allows the use of hydrogen. It is also possible to use gases such as helium and nitrogen.

Availability: Available to all NBS employees. Facility

must be operated by qualified Cryogenics Division

staff. Three months advance notice is necessary be- cause of large number of on-going experiments in the building.

Literature: NBS Technical News Bulletin October

1953, Vol. 37, No. 10, pages 152-158.

Contact: Dr. R. H. Kropschot, Chief, Cryogenics Division, Cryogenics Building, Room 2006, NBS Boulder, Colo. 80302. Phone 303-499-1000 ext. 4108.

LIQUEFIED NATURAL

GAS FLOW FACILITY

The Flow Facility is located behind a protective barrier at the Mesa Test Site, Boulder, Colorado. This

research facility allows the development of methodology for measurement of pressure, temperature,

flow, density, and state of LNG. It also provides the

opportunity to develop new methods of measure- ment for LNG where the unique characteristics of this fluid require advances in the state of the art.

Capability: The system consists of two vacuum-powder insulated tanks, vacuum insulated lines, valves,

pump, pumping system, weigh system and gas analyzer.

Flow rates can be varied from 2.5 to 13 liters per second with pressures up to 0.69 MPa (100 psi). Tank

gauging measurements can be made in the two in- sulated tanks. Gas analysis on both liquid and vapor

can be performed.

Applications: Flow measurements; temperature and

pressure measurements; liquid level measurements;

calorimetric analysis of delivered gas mixtures.

Availability: To qualified NBS and other Federal Government personnel. Facility operators will be provided.

Literature: American Gas Association Pipeline Re- search Summary, 1970, pages 13-14; 1971, pages 12-

13; 1972, pages 15-16; 1973, page 35; 1974, pages

33-34. Contact: R. S. Collier, Chief, Cryogenic Metrology

Section, Cryogenics Building, Room 1108, NBS

Boulder, Colo. 80302, Phone 303-499-1000 ext. 3178.

MACHINE TOOLS,

NUMERICALLY

CONTROLLED

MACHINE TOOLS,

NUMERICALLY

CONTROLLED

Numerically controlled machine tools are finding

wide application in industry, both on the production

line with long runs and in the job shop on single

intricate pieces. The units located in the National

26
Bureau of Standards Instrument Shops Division are primarily used for the short-run or single-piece application. Computer-assisted programming speeds the

preparation of tapes while providing capability for the generation of irregular, elliptic, and hyperbolic

curves. On the machining center, the generation of patterns and their rotation and/or translation are

easily accomplished.

Machining Center: This unit is a numerically controlled bed-type milling machine with an eight-sta- tion turret in which tools are mounted. Selection of these tools, as well as "on," "off," speeds, feeds,

positioning, end and side milling, drilling, tapping,

and boring cycles, are controlled through punched

paper tape. Selection of inch/metric operation, mirror

image, and EIA or ASCII(ISO) tape codes are accomplished by manual switches. Table travel of this machine is 20 inches by 40 inches. Vertical capacity of the machine is from 0 inch to 22 inches with 10

inches of this travel under tape control. The table

offers linear and circular interpolation while the vertical travel is point-to-point. Instrument Shops Divi- sion at the Boulder Laboratories has a similar machining center and a single spindle machining center.

Lathe: The lathe is of the slant-bed type with an

eight-station turret in which tools are mounted. It

is a two-axis machine offering linear and circular interpolation. It has capability for turning, drilling,

boring, threading, grooving, and knurling. All above

features, as well as speeds and feeds, are controlled

by punched paper tape. Inch/metric operation and

EIA or ASCII tape code formats are selected by manual switches. Capacity of this machine is IOV2 inches over the cross slide and longitudinal travel is 26

inches.

Coordinate Measuring Machine: A three-axis machine

interfaced with a digital readout system, computer,

and a Teletype unit. Measuring range of the machine

is 30 inches by 26 inches horizontal and 16 inches

vertical. Accuracy within any horiozntal plane is ±0.0002 inch. Vertical axis accuracy is ±0.0002 inch. A right-angle probe holder permits measuring details of vertical planes. Optical viewing screens and microscopes are available for non-contacting measurements.

Contact: Robert E. Lach, Shops Building, Room 136,

Phone 301-921-2349.

MECHANICAL

MEASUREMENT

FACILITIES

DEADWEIGHT FORCE

CALIBRATION MACHINES

These seven machines are the NBS standards for the

calibration of precise force-measuring instruments

such as proving rings, load cells, and other similar devices. The machines are not used for testing the

strength of materials or for calibrating scales and

other weighing equipment.

Capability: The machines apply specific calibration loads of high accuracy in the engineering units of the

pound-force and in some cases, as noted in the table below, in units of the kilogram-force. The accuracy

is better than 0.002 percent of load. The characteristics of the machines are as follows:

Maximum load 500 Ibf 6100 Ibf (3050 kgf) 25,300 Ibf (11,500 kgf) 112,00 Ibf 300,000 Ibf 1,000,000 Ibf

Minimum load 10 Ibf 200 Ibf (100 kgf) 400 Ibf (500 kgf) 300 Ibf 10,000 Ibf 50,000 Ibf

Units of intermediate loads

5 ibf 100 Ibf (50 kgf) 100 ibf (500 kgf) 1000 Ibf (note 1) 50,000 Ibf Note 1—Intermediate loads vary, 10,000 Ibf, 20,000 Ibf, and 30,000 Ibf depending on range.

Availability: The machines are not available for shared use and are operated only by personnel of the Engineering Mechanics Section. Arrangements

for the calibration of specific instruments on a fee

basis can be made and scheduled according to current work loads.

Literature: "Research and Testing Facilities of the En- gineering Mechanics Section, National Bureau of Standards, Washington, D.C." D. J. Chwirut, Nat. Bur. Stand. (U.S.) Spec. Pub. 370 (Jan. 1973). Contact: Roscoe L. Bloss, Chief, Engineering Mechanics Section, Engineering Mechanics Building, Room

219, Phone 301-921-2621.

27
UNIVERSAL TESTING MACHINE, TWELVE MILLION

POUND-FORCE.

FLUID FLOW

MEASUREMENT

Laboratory techniques provide precise measurement

of the flux of fluid in a closed system, to permit cali- bration of meters for fluid quantity and flowrate,

using air, water, and certain liquid hydrocarbons.

Capabilities: A liquid flowmeter calibrator is used for flow measurement of filtered and dried air supplied

from a compressor at rates up to 2700 scfm (cu

ft/min at 14.69 psia and 70°F). Air is fed through

sonic nozzles in 2, 3, 4 or 6-inch meter runs at pres- sures up to 110 psig (758 kNm--) through a special

three-way ball valve to a tank of known volume. The

mass rate of flow is computed from measurements

of the collection time and of pressure and temperature after the air is accumulated in the known vol- ume. Smaller flows, from 50 cm^ min-^ up to 50 scfm,

are measured with piston-type or bell-type provers. Flowrate of a liquid is measured by static or dynamic

weighing the quantity accumulated during a known

time interval. Rotation of the diverter valve controls

fluid collection in a weigh tank, with a switching

error less than 10 ms. Net weights are measured to within ± 0.01 percent on commercial lever balances

or weighing scales. The countertimer is accurate to one part in 10". Calibration reports are based (usually) on ten separate observations taken in groups of five successive runs on each of two separate days. These reported

values have an estimated overall uncertainty from

± 0.13 to ± 0.25 percent, depending on the sensitivity and repeatability of the system under test. Applications: Calibration of flowmeters of either

fixed restriction or moving element types, at rates from 0.03 to 10,000 gallons per minute (1.9 X lO-^ to 6.3 X lO-^mVs) for water, and from 0.03 to 1000

gallons per minute for liquids such as aircraft fuels. Calibration of critical-flow nozzles and other types of meters for gaseous flow, over the range from 50 cm^

min-i to 2700 scfm (1.5 kg/s).

Availability: Calibration services for Federal agencies,

and for industrial or commercial laboratories in USA

or abroad.

Literature:

[1] F. W. Ruegg and M. R. Shafer, Flow Measurement: Procedures and Facilities at National Bureau of Standards, ASHRAE Symposium,

San Francisco, CA, Jan. 19-22, 1970.

[2] Lief Olsen and G. P. Baumgarten, Gas Flow

Measurement by Collection Time and Density in a Constant Volume, First Symposium

on Flow, Pittsburgh, PA, 1971. Contact: F. W. Ruegg, Chief of Fluid Meters Section,

Fluid Mechanics Building, Room 111, Phone 301-921-

3681.

THREE-DIMENSIONAL

PRECISION

MEASUREMENT

In a numerically controlled machine tool, the cutters are positioned precisely by the digits on a punched

paper tape, or often by direct computer control. The

workpiece, instead of being removed from the machine for checking a single measurement, is inspected

28
as a finished piece for the accuracy of all its dimensions and angles. This automated metrology facility

is designed to meet the needs of such automated

production.

Capability: A 3-axis measuring machine built to state- of-the-art specifications will be housed in a stabilized environment, and can be operated either manually or under full control from a programmed computer. It has a working volume of 48 X 24 X 12 inches with

a 16-inch clearance under the bridge, and can detect

a difference in length of 0.250nm (10 micro-inches),

using a non-contacting sensor. Bulk disc storage of computer programs is provided, and a line printer

capable of graphic presentation is available. Refer- ence to the Si metre will eventually be provided by

a stabilized laser interferometer.

Applications: Provides digital data on probe position

in three dimensions, or two-dimensional graphic projection of complex three-dimensional shapes. Substitutes for the skilled handling of gage blocks, micrometer calipers, height gages, sine bars, straight edges,

polygons, plug and ring gages, master gears, and

thread wires.

Availability: To any NBS worker after minimal training. In appropriate instances, individual workers from

other Federal organizations may gain access to the

facility.

Literature: Simpson, J. A., Use of a microscope as a non-contacting microdisplacement device. Rev. Sci.

Instr. 42, 1378 (1971). Contact: Dr. J. A. Simpson, Acting Chief, Mechanics

Division, Metrology Building, Room B322, Phone

301-921-2171.

UNIVERSAL TESTING

MACHINE, TWELVE

MILLION POUND-FORCE

This hydraulicaily operated machine of 12-million

pounds-force capacity, believed to be the largest in the world, was designed to test large structural components and to apply the forces needed to calibrate force measuring devices of large capacity.

Capability: The machine can apply axial force of 12,000,000 Ibf in compression 6,000,000 Ibf in tension, and a transverse force of 4,000,000 Ibf to a flexural member. Working space between the screw columns is 8 feet 4 inches, and the working surface

of the main platen is 8 feet 4 inches by 15 feet. The

reinforced concrete foundation includes a tie-down

floor system with the following working strength

values:

Longitudinal bending

moment 12,500,000 Ibf-ft (over central 40 feet) 20,000,000 Ibf-ft Transverse bending

moment 467,000 Ibf-ft/ft of width

(over central 40 feet) 750,000 Ibf-ft/ft of width

Uniform bearing 940 Ibf/ln- Tenslle force on

anchor bolts 150,000 Ibf/boit There are two hydraulic capsules in the sensitive crosshead, one providing the force measuring function and the other for preloading. Pressure trans- ducers in a constant temperature oven on the cross- head provide signals to analog readout for force,

strain, and displacement, and also to a digital read- out calibrated to within ± 0.5 percent of the applied

load. Both coarse and fine adjustment of power cylinder motion (5 feet max.) are provided from the

control console.

Applications: Axial forces of 12,000,000 Ibf can be

applied to column sections or fabricated members

with lengths up to 58 feet, or to elastic devices such

as the load cells used to measure rocket thrust or

rolling mill forces. To apply the full 6,000,000 Ibf tension to eye bars, drill rod for undersea operations,

large diameter wire rope, and the like, both threaded

couplings and clevis fixtures are provided to take specimens up to 53 feet long. Transverse or flexural

tests under 4,000,000 Ibf load can be made on beams

and similar structures with lengths up to 90 feet.

Availability: To be negotiated, for prearranged schedule not interfering with the work of the Section or with Government priorities. Other requestors must

attest no competition with non-Government agencies.

Literature: A. F. Kirstein, Universal Testing Machine

of 12-Million-lbf Capacity, Nat. Bur. Stand. (U.S.) Spec. Publ. 355 (Sept. 1971); NBS Tech. News Bull. 55, No. 11, p. 174-5 (Nov. 1971). Contact: Roscoe L. Bloss, Chief of Engineering Mechanics Section, Engineering Mechanics Building,

Room 219, Phone 301-921-2621.

WIND TUNNEL

FOR UNSTEADY FLOWS

This facility is designed for the study of unsteady

conditions in low-speed aerodynamics.

Capabilities: In two test sections, 4.5 feet square by

16 feet in length, each fitted with a set of continuously rotating shutters, oscillatory flows of air can be generated at mean speeds from nearly zero up to 45 feet per second. Provision is also made for simu29
lating gusts and lulls of adjustable amplitude and

frontal duration and for varying the intensity and

scale of the free-stream turbulence. One set of rotat- ing shutters lags the other by a quarter-turn to give more uniform loading on the fan. The flow can be

oscillated sinusoidally at frequencies from 0.1 Hz to 25 Hz. The amplitude is limited to about 5 fps at 10

Hz but can be increased to 45 fps at 0.1 Hz. The

"time-constant" for the overall facility is approximately 0.2 seconds.

Applications: Such important problems in unsteady

aerodynamics as the dynamic response of various

types of wind-speed instruments, the effect of wind

loading on buildings and other structures under the

action of a variable wind, unsteady heat transfer phenomena, and unsteady boundary layers may be inves- tigated in this facility.

Availability: The direct use of this facility is limited to

staff members of the Aerodynamics Section or qualified guest scientists. However, it may be used indi- rectly through cooperative or contractual research

arrangements with other Government agencies or with private industrial organizations. Contact: Philip S. Klebanoff, Chief of Aerodynamics

Section, Fluid Mechanics Building, Room 105, Phone

301-921-3684.

NUCLEAR REACTOR

AND ASSOCIATED

FACILITIES

NUCLEAR REACTOR

The NBS research reactor is a high-flux reactor designed for materials research and analysis. It operates

around the clock at a power level of 10 MW, generating neutron fluxes averaging 10^* neutrons per square centimeter per second.

Capability: The intense neutron flux makes possible

a wide variety of experiments and investigations such

as crystal structure determination, lattice dynamics

measurements, phase transition studies, trace ele- ment analysis, radioisotope production, and radiation

effects studies. The neutrons are made available through beam ports, pneumatic tubes, and in-core

irradiation thimbles. The reactor facilities can be seen

NUCLEAR REACTOR. Plan view of the NBS reactor showing

beam ports, pneumatic tubes, and vertical thimbles.

in the diagram and include: 9 radial beam ports 2 through beam ports

2 cold-source beam ports

1 thermal column

4 pneumatic tubes

7 vertical thimbles in the reflector 10 vertical thimbles in the core

Availability: All but one of the beam ports and several of the vertical thimbles already have experimental equipments installed. These facilities and

their availability are described in the following pages. The remaining facilities listed above are available for suitable programs.

Literature: W. F. Sheely, The NBS Reactor: Its Description and a Guide to Use by Experimenters, NBS

Rept. 9081 (1966). Contact: Dr. Robert S. Carter, Chief of the Reactor

Radiation Division, Reactor Building, Room A106,

Phone (301) 921-2421.

FILTERED

NEUTRON BEAMS

Nearly monoenergetic nertrons with energies above

-^100 keV can be readily produced with adequate

yields in positive-ion accelerators, but there are no

convenient accelerator sources of monoenergetic

30
neutrons with energies below 100 keV. Much of the neutron dose, however, comes fronn neutrons in this energy range, and dosimetry development is severely

hampered by the lack of test facilities.

Capability: Thick scandium, iron, or silicon filters placed in a through tube of the NBS reactor result in monoenergetic neutron beams of 2 keV, 25 keV, or 144 keV, respectively. Calculated intensities are in the range of 10*^ n/cm--s, with very low gammaray background.

ENERGY: 2, 25 and 144 keV

ENERGY SPREAD: 10%

INTENSITY: 10^ n/cm-s (continuous beam)

EXPERIMENTAL LOCATIONS: two

GAMMA RAY BACKGROUND: very small owing

to filter's atomic absorption

Applications: The NBS filtered beams will constitute a primary neutron source facility for neutrons of 2 keV, 25 keV, and 144 keV. This facility is to function

as the point of reference for the development and

maintenance of secondary source capabilities at satellite locations, as well as providing means for the evaluation and calibration of new types of dosi- meters. The filtered beams will also be used for cross section

measurements, and fission physics measurements,

which require a high-intensity, monoenergetic,

"clean," continuous neutron beam.

Availability: Beam time is available to NBS staff, other agency and university users, industrial users, and guest workers. Operation only by qualified Division personnel under the direction of Dr. A. R. Schwartz or Dr. I. Schroder.

Literature: NBS Reactor: Summary of Activities, Oct. 1971-

Sept. 1972, Nat. Bur. Stand. (U.S.) Tech. Note

759 (Mar. 1973). Contact: Dr. Charles D. Bowman, Chief, Neutron

Standards Section, Radiation Physics Building, Room

B117, phone 301-921-2234.

INTERMEDIATE-ENERGY

STANDARD NEUTRON

FIELD (ISNF)

This facility provides a primary standard neutron field with a smoothly varying energy spectrum that may be

accurately calculated. The energy range of the neutron spectrum—95% of the spectrum is between 2 keV and 5 MeV—is just that of core neutrons in presently conceived U.S. fast breeder reactors. The

system, which is operated in the thermal column of the NBS rector, is one of several energy-distributed,

fast-neutron fields developed by the NBS Neutron

Standards Program.

Capabilities: The ISNF arrangement is fundamentally

simple: a spherical cavity in graphite, a thin shell of

^"B mounted at the center, and fission source disks

of -''^'U placed around the periphery of the cavity. Fission neutrons returning from the graphite give rise to the ISNF field at the center of the cavity: Total flux intensity ^10" n/cm- s Total fluence for 24 hour irradiation ~10"^n/cm2

Uniformity of the field <2% variation over 4 cm

Initial accuracy of flux and spectrum ±5%

Applications: Two general kinds of applications are planned for the ISNF: (1) measurement of absolute

and relative integral reaction rates for breeder reactor development; (2) calibration of various types of neutron detectors important for nuclear technology.

Availability: The ISNF facility will be operational late

in 1974. Experiments by outside users will be an essential feature of the ISNF measurements program but

they will require careful coordination and scheduling.

Literature: NBS Reactor: Summary of activities, Oct. 1971-

Sept. 1972, Nat. Bur. Stand. (U.S.) Tech. Note

758 (Mar. 1973). Contact: Dr. James A. Grundl, Neutron Standards Section, Reactor Building, Room A-120, phone (301) 921-

2421.

ISOTOPE SEPARATOR

LABORATORY

Isotopic separations are produced by the combined

action of an electric and a magnetic field on a stream

of ions, which is transmitted through an electrostatic lens system and a 90°-sector magnet to a dispersion

and target chamber.

Capability: Potentials up to 90 kilovolts produce ion

beam currents up to 100 microamperes. Sector elec- tromagnet of 150-centimeter radius. Mass dispersion

sufficient to separate all known isotopes. Target with

temperature control. Collimating aperture and lens system adjusts shape of beam.

Applications: Preparation of isotopically pure substances, irradiation of materials, studies of nuclear

structure, ion implantation in semiconductors, precise chemical sectioning of foils. Source material may

vary from gaseous substance to metallic oxide, with

31
contamination-free transport from radio-chemistry

laboratory.

Availability: By prior arrangement.

Literature:

[1] Nuclear Orientation of ^^Br in Iron. A. T. Hirshfeld, D. D. Hoppes, W. B. Mann, and

F. J. Schima. Hyperfine Interactions in Ex- cited Nuclei. Vol. 1, p. 335 (1971). Proceedings of International Conference at Rehovot,

Israel, Sept. 6-11, 1970. (Gordon and Breach

Sci. Publishers, New York.)

[2] The L/K Electron Capture Ratio in First-For- bidden "sKr Decay. W. M. Chew, A. C. Xenoulis, R. W. Fink, F. J. Schima and W. B. Mann. Nuci. Phys. A229, 79 (1974).

[3] Implantation of ^*N+ into Monocrystalline

GaN Films. A. N. Saxena, L. R. Weisberg,

W. B. Mann and F. J. Schima. Int. J. Appl.

Rad. Isotopes, 1, 33 (1975). Contact: Dr. W. B. Mann, Deputy Chief, Applied Radiation Division, Radiation Physics Building, Room

C1 18, Phone 301-921-2668.

NEUTRON

DIFFRACTOMETERS

These facilities at the NBS reactor include 4 two-axis neutron diffractometers for elastic scattering and crystal structure studies, and 3 three-axis neutron diffrac- tometers for inelastic scattering studies. All instru- ments are computer controlled, and software is available for a wide variety of experimental procedures.

Capability: Two of the two-axis diffractometers are equipped with full-circle goniometers for collecting

three-dimensional neutron diffraction data from sin- gle crystals. Incident wavelengths are from 1.0 to 1.25A, and the limiting scattering angle is from 100°

to 110°. The other two are suitable for diffraction measurements from polycrystalline or amorphous

solids, liquids, and single crystals when the necessary

information can be derived from measurements in a single zone. Incident wavelengths are variable from

O.9A to 2.5A, and the limiting scattering angles are up to 120°. The three-axis diffractometers can measure both quasielastically and inelastically scattered neutrons. The incident energy can be varied from 4

to 100 meV, and energy changes can be measured

from 0.5 meV to 100 meV. Cryostats are available to provide sample temperatures from 4 K to 300K. Some

high-temperature sample furnaces are also available.

All data are collected by computer control, and basic

reduction is also performed by the computer.

Applications: Two-axis diffractometers are used in studies of the structure of crystals, glasses, and simple

liquids. They are particularly suitable for studies of compounds containing hydrogen, compounds with

atoms having very similar or widely different atomic

numbers, and magnetic materials. Three-axis spectro- meters are used in studies of crystal and molecular

vibrations, and molecular reorientation and hydrogen

diffusion in solids.

Availability: Instrument time can be scheduled for appropriate experiments or projects of NBS staff after the proposed measurements are reviewed by the Users Committee for these facilities. Outside users can also be accommodated, depending on the type

of measurements and the available resources.

Literature: NBS Reactor: Summary of Activities, Oct. 1971-

Sept. 1972, Nat. Bur. Stand. (U.S.) Tech. Note

758 (Mar. 1973).

Contact: Dr. John J. Rush, Chief of Neutron Solid

State Physics Section, Reactor Building, Room A126,

Phone 301-921-3634.

NUCLEAR IRRADIATION FACILITIES. Samples are loaded

into pneumatic tubes for transport into the reactor.

32
NEUTRON RADIOGRAPHY

FACILITY

Neutron radiography may display contrasts unobtainable by x-radiography because of the varying atten- uation characteristics for the elements, the differ- ences in neutron attenuation between isotopes, and

the capability of neutron detection in high gammaray intensities.

Capability: A well-moderated neutron beam has been

extracted from the reactor thermal column for neutron radiographic use. The beam covers a detector

area of 12.5 cm diameter with a thermal neutron

intensity that can be varied from 5 X lO'n/cm^ s to

2 X 10'n/cm^-s, with a cadmium ratio [0.5 mm

cadmium cover on gold] of about 600. The beam di- vergence characteristics can be changed quickly to provide L/D (length to neutron aperture diameter)

ratios from about 180 (at the lower neutron intensity) to about 30. The gamma radiation intensity in the

beam is in the order of 2 rontgen per hour, suffi- ciently low that direct film techniques can be used

for detection. Detectors available with this facility

include direct methods (converters include gadolinium metal and scintillators) with films that provide

radiographs with total exposures from 5 x lO'n/cm^

to 10"n/cm2, activation transfer detectors (indium,

dysprosium, gold), track-etch plastics, and a neutron image intensifier-television system. The latter system

provides images at a rate of 30 frames per second

and permits object motion to be followed. The best

spatial resolution of the radiographs is in the order

of 10/j,m for high contrast objects. A darkroom

for processing radiographs is available at the Reactor.

Applications: With neutrons one can readily observe

materials containing hydrogen, lithium, boron, cadmium or several rare earths in combination with

other materials, even dense metals. Therefore, examinations of adhesives, fluids, explosives, plastics, or hydriding in metals becomes feasible, as does examination of items such as boron filament composites

or cadmium plating. Isotopic sensitivity permits, as examples, differentiation between hydrogen and deuterium, 235U 238(j^ or between ^^^Cd and other

cadmium isotopes. In addition, the fact that neutron images can be made by gamma-ray insensitive tech- niques leads to inspection capability for radioactive

materials.

Availability: Instrument time can be scheduled for appropriate experiments or projects of NBS staff after the proposed measurements are reviewed by the

User's Committee for these facilities. Outside users can also be accommodated depending on the type

of measurements and available resources.

Literature:

[1] NBS Reactor: Summary of Activities, Oct. 1971-Sept. 1972, Nat. Bur. Stand. (U.S.) Tech.

Note 758 (Mar. 1973).

[2] Dimensions/NBS, 59, 106 (May 1975).

Contact: Mr. Harold Berger, Reactor Radiation Division, Reactor Building, Room A-128, phone 301-921-

3634.

NEUTRON SCATTERING

SPECTROMETER

A double-crystal small-angle scattering spectrometer

is available at the NBS reactor to measure the neutron scattering from inhomogeneities in materials.

Capability: Using nearly perfect silicon crystals, the range of angular observation (3 seconds to 6 degrees

of arc) allows measurement of diffraction from "particles" of sizes ranging from about 10 to 10,000A.

Exploiting this high angular resolution is most appropriate when the correlations persist over distances of micrometres; for shorter-range correlations the resolution can be broadened by substituting matched

pairs of crystals with larger mosaic spread, thereby

greatly enhancing the beam intensity. The wavelength

of neutrons used in this spectrometer can be varied

from 1.5A to 4.oA in order to optimize the resolution

with the sample attentuation characteristics.

Applications: This spectrometer has applications in the determination of shape, size and interaction of macromolecules as well as similar properties of defects in materials, magnetic correlations at extended

distances, and density fluctuations near the critical point of phase transitions. Neutron small-angle scat- tering has particular application to submicroscopic

particles of low population densities, where light and

x-ray scattering suffer from absorption and poor res- olution.

Availability: Instrument time can be scheduled for appropriate experiments of projects of NBS staff, after the proposed measurements are reviewed by the Users Committee for these facilities. Outside users can also be accommodated depending on the type of measurements and the available resources.

Literature: NBS Reactor: Summary of Activities, Oct. 1971-

Sept. 1972, Nat. Bur. Stand. (U.S.) Tech. Note

758 (Mar. 1973).

33
Contact: Dr. Robert Carter, Chief, Reactor Radiation

Division, Reactor Building, Room A106, phone 301-

921-2421.

NUCLEAR IRRADIATION

FACILITIES

Capability: An extensive number of well-characterized

irradiation facilities offer a wide range of neutron and/or gamma environments to levels exceeding 10"

neutrons per square centimeter per second. These in- clude five distinct pneumatic facilities, eleven in-core

vertical thimbles with inside diameters up to 3V2

inches, and seven vertical reflector thimbles with 4V2

inch openings. These facilities are used simultaneously and can accommodate tens of thousands of samples a year.

Applications: Most common use is in neutron acti- vation analysis for detection of trace elements in parts per million, billion, or trillion. Other uses in- clude preparation of isotopes for tracer work, preparation of isotopes for medicine, production of gamma and positron sources, studies of radiation

damage, and the characterization of standard refer- ence materials.

Availability: All facilities are available to qualified

scientists. Each sample to be irradiated must be ac- companied by an irradiation proposal form for safety

review. The packaging of each sample must be ap- proved by the staff of the Reactor Operations Section,

who can also provide guidance in the preparation of the irradiation proposals.

Literature: W. F. Sheely, The NBS Reactor: Its Description and a Guide to Its Use by Experimenters, NBS

Rept. 9081 (1966).

Contact: Tawfik M. Raby, Deputy Chief, Reactor

Radiation Division, Reactor Building, Room A148,

phone 301-921-2523.

TIME-OF-FLIGHT

NEUTRON SPECTROMETERS

This instrumentation utilizes either crystal monochromators or phased-choppers to select monoenergetic

neutrons, which are scattered by a sample and detected 2.5 to 3.8 metres away by multiple neutron

detectors at scattering angles between 10° and 105°.

The energy of the scattered neutrons is determined

by time-of-flight analysis.

Capability: The spectrometers provide incident neutron beams ranging in energy between 3 meV (25

cm-i) and 100 meV (800 cm-^) and cover a spectral

range for inelastic scattering of 0.5 meV to 100 meV

(4 to 800 cm-i). The available resolution varies from

0.2 meV (at the lowest energies) to 5 meV. The range

of momentum transfers (Q) for elastic scattering is from 0.2A-1 to |10A The time-of-flight data collection is automatic, utilizing either a multichannel analyzer or a small computer. The spectrum is continuously observable on a scope and the data can be

printed out on paper tape or on a typewriter. A specially designed sample cryostat is available for spec- trum measurements on solid and liquid samples between 5 and 300K.

Applications: The spectrometers can be used widely

in the study of the dynamics of liquids and solids. Some applications include the study of crystal and

molecular dynamics of solids, vibrational spectra of

glasses, hydrogen diffusion in metals, orientational

disorder and relaxation processes in polymers and

molecular crystals, and the dynamics of liquids.

Availability: Instrument time can be scheduled for appropriate experiments or projects of NBS staff after the proposed measurements are reviewed by

the Users Committee for these facilities. Outside

users can also be accommodated depending on the

type of measurements and available resources.

Literature: NBS Reactor: Summary of Activities, Oct. 1971-

Sept. 1972, Nat. Bur. Stand. (U.S.) Tech. Note

758 (Mar. 1973).

Contact: Dr. R. S. Carter, Chief, Reactor Radiation

Division, Reactor Building, Room A106, Phone 301-

921-2421.

34
RADrOACTIVE

SOURCE

COBALT-60

IRRADIATION

FACILITY

Capabilities: The facility consists of twelve rods containing ""Co mounted in a circle on a plate at the

bottom of a water pool 10 feet deep. The dose rates available range from about 2 x 10" rad/h (in carbon)

at the center of the source array to about 2 x 10^ rad/h near the edge of the mounting plate as of February 1974; these values decrease by about 10%

per year. Samples as large as 5 cm high by 5 cm in diameter can be given reasonably uniform doses at the center position of the source array. Samples may

be irradiated under various atmospheric conditions

and over a wide range of temperatures.

Applications: This facility may be used to study the

effects of gamma radiation on various materials such

as polymers and electronic components. It may also be used as a standard calibration source for calibrat- ing different types of radiation dosimeters such as thin polymer dye films.

Availability: Generally available to NBS personnel or

qualified guest scientists on a scheduled basis.

Contact: J. C. Humphreys, Applied Radiation Division,

Room C216, Radiation Physics Building, phone 301-

921-2201.

RADIO STATIONS

Transmitter buildmgs and antennas of WWVL, WWVB, and

WWV at Fort Collins, Colorado.

WWVL VLF

BROADCAST STATION

WWVL is an experimental very-low-frequency (VLF)

radio station located on the same Ft. Collins, Colorado, site as radio stations WWV and WVWB. Prior to July 1, 1972, it was operated by the Time and

Frequency Division on a regularly scheduled basis to provide stable and accurate frequencies and timing

information referenced to the NBS primary standards. Various combinations of 1-3 timeshared carrier fre- quencies were transmitted in the region of 20 kHz.

Regular scheduled broadcasts were terminated as of

July 1, 1972.

Capability: Approximately 2 kW radiated power; multiple carrier frequencies (timeshared) in the region of 20 kHz; carrier frequencies and phases can be controlled relative to NBS primary standards.

Applications: Propagation research at VLF; frequency

and time dissemination via multiple VLF carriers.

Availability: Operation of the WWVL facility is the

responsibility of the full-time Ft. Collins field site

staff. Installation, maintenance, and monitoring of any

special equipment involved in special experiments

by other government agencies must be arranged with

R. E. Beehler or the Engineer in Charge at Ft. Collins, Mr. J. Milton.

Contact: R. E. Beehler, Chief, Time and Frequency

Services Section, Radio Building, Room 4039, NBS

Boulder, Colo. 80302. Phone 303-499-1000 ext 3282.
SPECIAL

ANNOUNCEMENTS

ONWVW/WWVH

Radio stations WWV in Ft. Collins, Colorado, and

WWVH in Kekaha, Kauai, Hawaii, are operated by the

Time and Frequency Division of NBS for the dissemination of standard frequency and time information.

Transmissions are on a continuous basis, simultaneously on 2.5, 5, 10, 15, and 20 MHz from both sta- tions. In addition, WWV also transmits at 25 MHz. Es- sentially worldwide coverage is achieved.

Capability: In addition to the primary time and fre- quency information provided, the WWV and WWVH

formats include 45-second segments every other minute, most of which can be made available on a subscription basis to other government agencies for dissemination of official and public service information. Each prerecorded voice announcement will be

repeated once per hour and will appear on all trans- mitted frequencies. A wide variety of commercial

receivers are readily available that provide adequate

reception.

Applications: Presently, voice announcements have

been arranged for marine weather advisories by

NOAA, geoalert messages by NOAA, radio propagation forecasts by the Office of Telecommunications,

and Skylab-related information by NOAA. Decisions

regarding suitability of proposed announcements for inclusion in the WWV/WWVH format will be the

responsibility of NBS.

Availability: All segments except those reserved for NBS use, the semi-silent period, and those presently

in use by other agencies are available. The content

of all announcements accepted for inclusion in the

broadcast formats will be the responsibility of the

sponsoring agency and must be transmitted to the Ft. Collins or Hawaii sites by teletype or other suitable means. The permanent station staff will be responsible

for prerecording the information supplied (if necessary) and for arranging for broadcast of the information at the proper times. Provisions can be made for

a reasonable frequency of updating of the material

broadcast.

Literature: NBS Frequency and Time Broadcast Services, Viezbicke, P.P., Nat. Bur. Stand. (U.S.) Spec.

Publ. 236 (March 1974).

Contact: R. E. Beehler, Chief, Time and Frequency

Services Section, Radio Building, Room 4039, NBS

Boulder, Colo. 80302. Phone303-499-1000 ext 3282.

SPECTROSCOPY

FACILITIES

ANALYTICAL SPECTROPHOTOMETER.

ANALYTICAL

SPECTROPHOTOMETER

This high-accuracy spectrophotometer, with good

sensitivity and linearity, will check the photometric

scale accuracy of the transmittance of either solid or

liquid filters used in commercial spectrophotometers.

Capability: The single-beam spectrophotometer is capable of measuring transmittance (T) values on

solid and liquid materials to within an uncertainty of one part in 10^ T units. It consists of a constant radi- ation source (stability 7 parts in lO'^), a double monochromator, adequate sample holders (one being auto- mated through computer interfacing), and an averaging sphere with photomultiplier tube assembly. The

latter is connected to a digital voltmeter; data acquisition and presentation is performed in a computer.

Applications: Spectrophotometric (colorimetric) analysis is the predominant technique for bioclinical ex36
amination of various body fluids and solids, and for other measurements involving health problems. This

instrument is used to certify colored glass filters (SRM

930) between 300 and 700 nm, at three transmittance

levels to within an uncertainty of one part in 10* T

units. Ampoules containing solutions (SRM 931) are

particularly designed to be used in conjunction with

flow-type spectrophotometers in both visible and

ultraviolet regions. These SRM's were developed to meet the particular needs expressed by clinical chemists organizations. The technique is also widely used

for environmental studies of smog, stack emissions, stream pollutants, and atmospheric contaminants.

Availability: Only limited time is presently available

for other agencies, because of the SRM certification program, research on stable materials, reproducible

methods for transmittance measurements, spectral

bandwidth and stray light determinations.

Literature:

[1] R. Mavrodineanu, NBS J. Res. 76A, No. 5, 405-425 (Sept.-Oct. 1972); NBS Tech. News

Bull. 56, No. 7, pages 166-167 (July 1972).

[2] R. Mavrodineau, Spectrophotometry Instru- ment Development, NBS Tech. Note 584, pp.

9-21, (June 1971).

[3] R. N. Rand, Practical Photometric Standards,

Clinical Chemistry 15, 839-863 (September

1969).

Contact: Dr. R. Mavrodineanu, Special Analytical In- strumentation Section, Room A205, Chemistry Building, phone 301-921-2861.

CONCAVE GRATING

SPECTROGRAPHS, 10.7m

The Spectroscopy Section has three 10.7-m concave

grating spectrographs for use in different portions of the photographic region:

1. About 2000 to 12000 A—air region, normal

incidence

2. About 450 to 2500 A—vacuum ultraviolet region, normal incidence

3. About 75 to 600 A—vacuum ultraviolet re- gion, grazing incidence at 10°. These instruments can be used for the photographic

recording of ail types of atomic and molecular

spectra.

Capability: The 10.7-m concave gratings with 1200

grooves/mm give resolving powers of over 150,000

and plate factors of about 0.77 A/ mm in the first

spectral order of the normal incidence instruments.

The plate factor of the grazing incidence spectrograph varies from 0.17 A/mm at 70 A to 0.32 A/mm

at 600 A.

Applications: These spectrographs have been used

in conjunction with mild discharge light sources for the photographic recording of the spectra of neutral and single ionized spectra of a wide variety of ele- ments, and in conjunction with spark discharges for the similar acquisition of highly-ionized spectra.

Availability: To any qualified research worker, in the

immediate past, guests from Kitt Peak, Naval Research

Laboratory, Canada, The Netherlands, and France,

have used the spectrographs.

Contact: Dr. William C. Martin, Jr., Chief of Spectroscopy Section, Physics Building, Room A167, Phone

301-921-2011.

CZERNY-TURNER

HIGH DISPERSION

SPECTROGRAPH

This is a high resolution, high dispersion, stigmatic,

plane grating spectrograph. The grating is 220 X

135-mm, has 300 grooves/mm, and is blazed at 63°26' (6fim). It is used in the fifth to the thirtieth order. A predisperser used in conjunction with this spectrograph separates or eliminates overlapping

orders.

Capability: The resolving power of the instrument is about 700,000 at 4000 A (fifteenth order). The plate factor is about 3.6/n A/mm (n = order number).

The instrument can be used from 2000 to 12000A.

Applications: This instrument has been used for a wide variety of atomic and molecular spectroscopic

studies for which high resolution was necessary. The

stigmatic property of the spectrograph is useful for spectral separation in types of discharges where dif- ferent ions are excited in different areas. It can be

used for cross-dispersion with interferometers.

Availability: To any qualified research worker. In the

immediate past, guests from Kitt Peak, Naval Research

Laboratory, Canada, The Netherlands, and France,

have used the spectrograph.

Literature:

[1] J. Reader, L. C. Marquet, and S. P. Davis,

Predisperser for high-resolution grating spectrographs, Appl. Optics, 2, 963 (Sept. 1963).

[2] J. Reader, Optimizing Czerny-Turner Spectro37
graphs, J. Opt. Soc. Amer. 59, no. 9, 1189-

1196 (Sept. 1969).

Contact: Dr. William C. Martin, Jr., Chief of Spectroscopy Section, Physics Building, Room A167, Phone

301-921-2011.

ELECTRON ENERGY

LOSS SPECTROMETERS

FOR GASES

Three state-of-the-art electron energy loss spectro- meters allow measurements of the energy loss spectra of gases with an energy resolution of 15 to 50

milli-electron volt with incident energies from thresh- i old to several hundred electron volts.

Capabilities: Energy loss spectra of gases. Excitation functions near threshold. Analysis of gas mixtures.

The spectrometers are controlled and data taken by

an Interdata 70 computer. Computer programs for gas analysis and for plotting of data are available.

Availability: Because of the complexity of instrumentation, the direct use of these spectrometers is limited to: (a) permanent members of the laboratory;

and (b) qualified full-time guest scientists with ap- pointments exceeding six months. The spectrometers

may be used indirectly through cooperative or contractual research agreements.

Literature:

[1] R. Celotta, S. R. Mielczarek, and C. E. Kuyatt,

NBS Report 10 915 (September 1972).

[2] N. Swanson, C. E. Kuyatt, J. W. Cooper and

M. Krauss, Phys. Rev. Letters 28, 948 (1972).

[3] G. E. Chamberlain, S. R. Mielczarek and C. E. Kuyatt, Phys. Rev. A 2, 1905 (1970). Contact: Dr. Chris E. Kuyatt, Chief, Surface and Elec- tron Physics Section, Metrology Building, Room B214,

Phone 301-921-2051.

FAR INFRARED

SPECTROSCOPY

Far infrared spectroscopy studies the absorption,

transmission or reflection of long wavelength, lOOOyx

to lOju (10" — 10*nm), electromagnetic radiation

which is caused by vibrations, rotations, and transla- tions which modulate the dipole moment of the

atoms and molecules in the sample. It is a useful tool

for the identification of molecular or ionic species in the liquid, solid, and gaseous states.

Capability: The techniques of Fourier transform spec- troscopy are applied in the far infrared instrument.

The range of 10 — 1000 cm-^ can be measured with

a resolution of 0.5 cm ^ The radiation detector is a

triglycine sulfate (TCS) pyroelectric crystal. The Michelson interferometer employs a high precision air bearing translator, and a He-Ne laser is used for dis- tance measurement. Data output is typically graphical and is processed by an on-line computer which

also serves to control the instrument throughout the

experiment. Specimens can be studied by transmission or reflection as is necessary. Facilities are pro- vided for sample temperature variation between 10 K

and 300 K and for matrix isolation.

Applications: Molecular and crystal dynamics as dis- played by translational, rotational, librational and

vibrational degrees of freedom are measured as a function of parameters such as temperature, pressure, stoichiometric relations, electric or magnetic fields, concentration and phase. Typical applications involve

the spectra of matrix isolated free radicals and molecules, lattice and molecular dynamics of polymers,

phase transitions in solids (including melting), studies

of isomerism, vibrational and rotational studies in gases, investigation of stoichiometry in crystals and

disordered solids, and measurements of chemical re- action products.

Availability: The instrument is available to qualified

research workers, following a training period in its use. Proposed research projects require the approval

of the instrument manager, or in special cases, of the

users committee.

Literature:

[1] C. Horlick, Appl. Spectrosc. 22, 617 (1968).

[2] P. R. Griffiths, C. T. Foskett, and R. Curbelo,

Appl. Spectrosc. Revs. 6, 31 (1972). Contact: Dr. Marilyn E. Jacox, Acting Chief of En- vironmental Chemical Processes Section, Chemistry

Building, Room A243, Phone 301-921-2754.

FLAME EMISSION

SPECTROMETER

WITH REPETITIVE

OPTICAL SCANNING

Repetitive optical scanning for flame emission spec- trometry provides a unique way of minimizing spectral interferences in matrices and flame gases. By

measuring the second derivative of the output in- tensity, a small signal from an atomic emission line can be readily discerned from a very large continuum.

This is especially useful when dealing with the high

38
temperature flames and plasmas which are needed to excite the more refractory elements. At the same time

this technique requires a minimum of sample.

Capabilities: The instrument provides the capability of quantitative measurements at the parts per million

level or less for thirty elements in a large variety of matrices with a precision of 0.2 to 5 percent. For many of these analyses only 50 fi\ of solution is necessary per analysis.

Application: This instrument is presently being used

to characterize many of the trace elements in Standard Reference Materials and other related materials. Typical examples include Li, Na, K and Ca in serum,

liver, orchard leaves, fertilizer and clays; Ca, Sr and

Ba in steels; Al in high purity steel and phosphate

rock; Li in both fresh and sea water; Zr, La and Sr in optical quality glass; Ni and Co in steels and ores; Gd in calcium fluoride; Pd and Ru in alloys and Tl in organic compounds.

Availability: To any qualified research worker, but

because of the complexity of the instrument and

safety in the handling of high temperature flames and

plasmas, the operation of the facility is limited to permanent members of the Analytical Spectrometry

Section.

Literature:

[1] W. Snelleman, T. C. Rains, K. W. Yee, H. D. Cook, and O. Menis, Flame emission spec- trometry with repetitive optical scanning in the derivative mode. Anal. Chem., 42, 394

(1970).

[2] O. Menis, editor. Flame emission and atomic

absorption spectrometry, NBS Technical Note

504 (1969), pp. 1-8.

[3] O. Menis and J. I. Shultz, editors. Analytical

flame spectroscopy, NBS Technical Note 544,

(1970), pp. 58-86.

Contact: Theodore C. Rains, Analytical Spectrometry

Section, Chemistry Building, Room B222, Phone 301-

921-2142.

FLASH PHOTOLYSIS

RESONANCE

FLUORESCENCE

APPARATUS

Fluorescence measuring techniques have proven to be quite sensitive and versatile for the detection and

monitoring of many short-lived species. The existing

NBS facility for the production and subsequent kinetic detection of reactive atomic and free radical species incorporates such fluorescence techniques

and is the precursor of several similar pieces of ap- paratus in chemical laboratories throughout the

world.

Capability: Gas mixtures of an atom or free-radical source compound, reactant substrate, and inert dil- uent (from 1 torr to 1 atm in total pressure) are subjected to a flash pulse (electrical discharge or laser). The atoms or free radicals photolytically produced

are subjected to the cw radiation of a microwave

resonance flow lamp or the delayed pulsed radiation of a suitable laser. The scattered radiation is subsesequently monitored as a function of time to obtain

the kinetic history of the reactive species. Experiments can be conducted at temperatures ranging

from 200 to 500 K.

Applicability: The technique is presently suited for the study of chemical dynamics of systems involving

H, O, N, S, CI, C, and Br atoms as well as OH radicals. With suitable resonance lamp development, the

technique can be extended to numerous other reactive species. The range of experimental conditions

overlaps those desired for investigations involving air pollution, combustion processes, planetary atmosphere, chemical laser systems, etc.

Availability: The apparatus is presently being used

full-time for chemical kinetics studies of atmospheric

interest and for laser induced chemical processes. Outside use is consequently restricted to short-term

problems suitable for study on a cooperative basis.

Literature:

[1] E. L. Baardsen and R. W. Terhune, Appl. Phys.

Lett. 21, 209, (1972).

[2] M. j. Kurylo, J. Phys. Chem. 76, 3518 (1972).

[3] F. Stuhl and M. Niki, J. Chem. Phys. 57, 3671

and 3677 (1972).

Contact: Dr. Michael J. Kurylo, Environmental Chemical Processes Section, Chemistry Building, Room

A253, Phone 301-921-2080.

FOURIER TRANSFORM

NUCLEAR MAGNETIC

RESONANCE SPECTROMETER

This high-resolution instrument utilizes the magnetic

moment of ^'C nuclei to probe the molecular dynamics and structure of polymeric materials.

39
Capability: Requires sample concentration of at least 0.05 mole in 2 m/of solution. Magnetic field operates

at 1.4T, corresponding to a resonance frequency of 15.08 MHz. Spinning resolution of 0.5 Hz over 10 mm

sample tube; 90° rotation of magnetization requires

pulse of <5jLis duration and pulse programmer allows

180°-T-90° pulse sequence to be performed. A computer with 8000 words is available for accumulation

and processing of data.

Applications: Identification of monomers and poly- mers in solution; identification of molecular rota- tional isomers; determination of polymer tacticity, cross-link and branches; determination of polymer

chain dynamics in solution and in the solid state; determination of molecular conformation and struc- ture of biopolymers and proteins.

Availability: The use of this instrument by NBS re- search workers on problems of mutual interest can be arranged. It must be operated only under the

direct supervision of the scientist in charge of the

instrument.

Contact: Dr. Darrell H. Reneker, Chief of Structural Analysis and Standards Section, Polymer Building,

Room A209, Phone 301-921-3344.

GAS CHROMATOGRAPHMASS SPECTROMETER

SYSTEM

The gas chromatograph-mass spectrometer-computer

system is designed for organic chemical applications,

particularly trace organic analysis and structural identification. The system uses a quadrupole spectrometer

and includes both electron impact and chemical ioni- zation sources.

Capability: The gas chromatograph-mass spectrometer system is capable of measuring mass spectra

with unit mass resolution from m/e 2 to 650 at a maximum scan speed of 325 amu/s. The gas chromatograph is equipped with linear temperature pro- gramming, dual column operation, thermal conductivity, flame ionization, and electron capture detectors. The mass spectrometer is controlled by a 16K

word, 16 bit data acquisition and control system. The

data system includes two 1.2 million word discs, pro- grammable read-only memory, and an interactive dis- play terminal. Both glass jet and membrane separators

are available for the CC-MS interface.

Applications: Mass spectrometric analyses of gas chromatographic effluents from samples of biological

and environmental origin are the predominant current applications. Other work in progress includes

isotope dilution mass spectrometry, precision of quantitation for both electron impact and chemical

ionization, and spectrometric measurement and identification of impurities in Standard Reference Materials.

Availability: A limited amount of time is available

for other groups and agencies. Laboratories with chal- lenging analytical problems are encouraged to enter

into collaborative programs with the Section, particularly in the areas of biological materials, clinical analysis, and trace organic analyses in the environ- ment.

Contact: Dr. Robert Schaffer, Chief of the Bio-organic

Standards Section, Chemistry Building, Room A367,

Phone 301-921-2866.

HIGH PRESSURE

PHOTOIONIZATION

MASS SPECTROMETER

This instrument combines a photoionization and re- action chamber with a mass spectrometer in order to investigate the interactions of positive and negative

ions with neutral molecules in the vapor phase.

Capability: Ionization of pure samples or mixtures

may be induced by photoabsorption at 8.4, 10.0, 11.7,

16.7, or 21.2 eV over the pressure range 10-* to ap- proximately 3 torr. Accurate rate constants are obtained between 200 and 350 K for bimolecular and

relatively fast termolecular reactions involving ion- neutral collision processes. The kinetics of higher or- der processes including collisional stabilization and

ionic solvation reactions may also be easily defined.

Applications: Determination of accurate rate constants for ion-molecule reactions; effect of internal energy and pressure on reaction rates; elucidation of ionic polymerization mechanisms; analysis of trace components using chemical ionization techniques;

laboratory simulation of planetary ionospheres; determination of ionic fragmentation patterns for correlation with photoelectron spectroscopy.

Availability: Contingent upon contract commitments

and direction of in-house program. In appropriate

instances qualified scientists from NBS, other federal organizations, and private institutions may collab- orate on problems of mutual interest to Ihe operators.

Literature:

[1] J. Am. Chem. Soc. 91, 7627 (1969).

40
[2] J. Chem. Phys. 53, 794 (1970).

[3] J. Am. Chem. Soc. 92, 2937 (1970). Contact: Dr. Wayne Sieck, Environmental Chemical

Processes Section, Chemistry Building, Room A255,

Phone 301-921-2783.

HIGH RESOLUTION

INFRARED SPECTROMETER

This facility consists of a high resolution vacuum spec- trometer with associated hardware and software to cover the infrared region from 5.5 ^m to 1.5 ixm. The

instrument is available for measuring high resolution

spectra of molecules in the gas phase.

Capability: This instrument operates in the spectral

range from 1850 cm-i to 6000 cm-^ with a resolution of about 0.03 cm-^ a precision of measurement of ±0.002 cm-^ and an accuracy of measurement of about ±0.006 cm ^ The entire optical path can be

evacuated to eliminate absorption due to atmospheric

constituents. Facilities are available for making measurements on gas samples in the temperature range

from —76°C to +1200°C. A variable long path ab- sorption cell is also available, providing absorption

paths up to 39 meters. The spectrometer output is recorded directly on magnetic tape, and software is available for processing the output on a digital computer to automatically provide an atlas listing the

frequencies and intensities of absorption lines.

Applications: Fields of applications for these measurements are: air pollution, terrestrial and planetary

atmospheric measurements, measurements on cool

stars, molecular structure, studies of reaction inter- mediates and reaction products, flames and high temperature studies, thermodynamics, mechanisms of

laser action, properties of chemical bonds, energy

transfer mechanisms, and many more.

Availability: Instrument time is available for any

projects which properly utilize the unique high res- olution capabilities of this instrument. Contact: Dr. Arthur Maki, Chief of Molecular Spectroscopy Section, Physics Building, Room B268, Phone

301-921-2021.

ISOTOPE RATIO

MASS SPECTROMETERS

The laboratory contains all the necessary chemical

and mass spectrometric equipment for the determination of isotopic ratios at the "state of the art" accuracy level for ail elements that will ionize by either surface or thermal methods.

Capability: The range of available equipment is such

that almost any size sample down to 10 " grams can be handled, for both absolute isotopic abundance

ratio determinations or the determination of trace element concentration by isotope dilution.

Applications: Current applications include the deter- mination of the absolute isotopic abundance ratios and atomic weights of the polynuclidic elements, the determination and certification of the absolute iso- topic abundance ratios for standards of interest to the nuclear energy industry and the geochemist, the

geochemical age determinations (Pb-U-Th, Rb-Sr) on

lunar materials, and the determination of trace concentrations of a wide variety of elements in almost

any conceivable matrix.

Availability: The facility is available to any qualified

guest worker interested in high-accuracy analysis,

but does require a three to six months training

period.

Literature:

[1] NBS Technical Note, 456, Nov. 1968, pp 1-47.

[2] NBS Technical Note, 506, May 1970, pp 1-48.

[3] NBS Technical Note, 546, Nov. 1970, pp

1-110.

Contact: Dr. I. L. Barnes, Analytical Spectrometry Section, Physics Building, Room A25, Phone 301-921-

3674.

MICROWAVE SPECTROSCOPY FACILITY. Millimeter-wave

parallel plate absorption cell with discharge production

system.

MICROWAVE

SPECTROSCOPY FACILITY

The microwave spectroscopy laboratory at the National Bureau of Standards has had a long history of

41
research into problems involving extensive development of microwave instrumentation. Pioneering ef- forts in the study of transient and high temperature

molecules have led to designs and techniques which

affect spectrometer performance in many ways. Operational flexibility and sensitivity have been significantly extended in both the high and low frequency extremes of the traditional microwave region.

Capability: Two separate spectrometer systems are

available with klystron sources and requisite hardware

to cover the complete range from 2 to 132 GHz.

Harmonic generation equipment extends the operation further into the millimetre region. Conventional

septum-type waveguide absorption cells, used for studies of static systems, include a 12 ft gold-plated

cell (3.3 GHz cutoff), 15 ft brass cell (8 GHz cutoff), and 4 ft all-stainless and Teflon cell for special handling of reactive gases (12 GHz cutoff). All three

conventional cells can be cooled to dry ice and the

special stainless cell may be heated to 300°C. Several

parallel plate cells are available complete with dis- charge and pyrolysis sample generating apparatus

and fast-continuous-flow vacuum systems. Special ovens will allow operating temperatures to 1000°C

for certain experiments.

Applications: Analyses of rotational spectra of polar

gas-phase molecules yielding structural parameters,

electric dipole moments, quadrupole coupling constants and spectroscopic details such as vibrationrotation interactions, etc. Stable molecules with vapor

pressures of a few micrometres of Hg at temperatures below 1000°C are readily accessible. A variety of small transient molecules with lifetimes of the

order of 10 ms have been successfully studied in the

flow systems. Certain laser-microwave double res- onance and laser pumped reaction systems are also within the range of capabilities.

Availability: To qualified research workers on a col- laborative basis with NBS staff or in special cases where background and experience is adequate on a guest worker basis. It should be emphasized that these spectrometer systems are hand-built, state-of- the-art devices and require extended experience for competent operation. Contact: Dr. Donald R. Johnson, Molecular Spectroscopy Section, Physics Building, Room 8268, Phone

301-921-2021.

MOSSBAUER

SPECTROSCOPY

OF METALS

Mossbauer effect utilizes the nuclear properties of various isotopes to probe the local chemical, magnetic

and electronic environment of an atom embedded

in a solid material. By detecting the conversion elec- trons that emanate from a sample, very thin surface

layers can be studied. Differences between the sur- face and bulk can be observed by also detecting the

primary Mossbauer effect gamma rays.

Capability: Solid specimens of irregular shapes with

outside dimensions up to 30 cm can be utilized. Minimum size is about 0.5 cm diameter and 5^m thickness. Transmission spectra can be obtained (on powders or foils) as a function of temperature in applied

magnetic fields up to 50kG. On selected specimens,

time delayed perturbed angular correlation or posi- tron lifetime studies can also be made.

Applications: Measurements of isomer shifts, magnetic hyperfine fields and electric field gradients per- mit studies of phase composition, magnetic properties, electronic structure and diffusion. Applications

to corrosion studies, surface effects, and other metallurgical problems.

Availability: To any qualified NBS research worker.

In appropriate instances, researchers from other or- ganizations can gain access to the facility. Scientists from U.S. universities, federal agencies and industries, and from abroad have qualified to use this equipment in the past.

Literature:

[1] Nuclear Resonances in Metals: NMR and

Mossbauer Effect by I. D. Weisman, L. J. Swartzendruber and L. H. Bennett in Measurement of Physical Properties, E. Passaglia

and R. F. Bunshah, Editors. (Wiley-lnterscience, New York), V. 6(2), 1973.

[2] Mossbauer Spectrometer Calibration Using

TiFe, Nat. Bur. Stand. (U.S.) Tech. News Bull. 54, No. 10, page 239 (1970). Contact: Dr. L. H. Bennett, Chief of Alloy Physics

Section, Materials Building, Room B150, Phone 301-

921-2982.

MULTICHANNEL

FLAME SPECTROMETER

This flexible system was designed and assembled at NBS to perform precise spectral measurements in the emission and atomic absorption modes using

flames or similar high temperature "thermostates."

The spectrometer used to detect the radiations originating from the excitation source is a conventional

1-m grating instrument, arranged to focus on a photographic plate, a variable exit slit, or a metal plate

with eight exit slits.

42
Capability: Operable as a spectrograph, a scanning

monochromator, or a multichannel instrument.

Measures in emission and atomic absorption modes

for one element at a time, or up to 8 chemical species

simultaneously. The output is either analog or digital.

Applications: Analysis for alkali and earth alkali metals in body fluids, agricultural products, soils, air, and water samples; for elements from the I to VIII groups in alloys; for trace elements such as Pb, Cd,

Hg, Cu, Cr, Ni.

Availability: To any qualified NBS research worker,

after an initial training period by R. Mavrodineanu.

Literature:

[1] R. Mavrodineanu, Discussion of some ex- perimental and fundamental flame spectro- scopy. Revue CAMS, 1971, no. 3, 39-60.

[2] R. Mavrodineanu and H. Boiteux, Flame

Spectroscopy, John Wiley and Sons, 1965,

pp. 721.

Contact: Dr. R. Mavrodineanu, Assistant Chief, Special Analytical Instrumentation Section, Chemistry

Building, Room A205, Phone 301-921-2861.

NUCLEAR MAGNETIC

RESONANCE SPECTROSCOPY

The NMR method makes use of the magnetic and

electric moments of atomic nuclei to probe the local environment about selected nuclei in materials. Appropriate nuclei of virtually any chemical element

can be used, but considerations such as isotopic

abundance, sensitivity and atomic motion restrict studies to preselected problems.

Capability: Metallic specimens generally should be

in the form of —325 mesh powder, but other forms

including single crystals are possible. Wide-line NMR

spectroscopy with laboratory electromagnet and

high-power pulsed NMR spectroscopy with super- conducting magnet. Data acquisition system used for

sensitivity enhancement. Ferromagnetic NMR spectroscopy also available. Temperature and pressure varia- tions possible.

Applications: Measurements of Knight shifts, relaxa- tion times, electric quadrupole interactions and line- shapes permit studies of electronic structure, defect

structure and diffusion. These have been important

primarily in the study of metals, alloys, and inter- metallic compounds but occasional attention has

been given to practical problems outside of metallurgy such as detecting cancer in live mice utilizing

NMR.

Availability: To any qualified NBS research worker,

in appropriate instances, researchers from other or- ganizations can gain access to the facility. Scientists from U.S. universities, federal agencies and industries, and from abroad have qualified to use this equipment in the past.

Literature: Nuclear Resonances in Metals: NMR and

Mossbauer Effect by I. D. Weisman, L. J. Swartzen- druber and L. H. Bennett in Measurement of Physical

Properties, E. Passaglia and R. F. Bunshah, Editors. (Wiley-lnterscience, New York , V. 6(2), 1973.

Contact: Dr. Lawrence H. Bennett, Chief of Alloy

Physics Section, Materials Building, Room B150,

Phone 301-921-2982.

MULTICHANNEL FLAME SPECTROMETER.

PHOTOIONIZATION MASS

SPECTROMETRY

The photoionization laboratory operates and maintains two major equipment items for use in basic studies of photoionization processes in low pressure gases and vapors. This is a powerful technique for the accurate determination of ionization thresholds

for molecular, dissociative, and ion-pair processes as well as the study of the spectroscopy of ions.

Capability: Each unit consists of a windowless vac- uum ultraviolet monochromator combined with a

43
magnetic mass spectrometer for the detection and

identification of photoions. The best optical resolu- tion available at present is 0.012 nm in the first order over the wavelength region of 130 to 60 nm. Included

in the apparatus is a step-controlled grating drive,

digitized photon detector, and the programmed control of wavelength, ion and photon recording and the

print-out of data. Automatic computation of ion

yield and the plotting of original or smoothed data

is a present capability. The ion source of the mass

spectrometer can be cooled to 115 K or heated to 500 K to enable the identification of effects due to thermal excitation of molecules under study.

Applications: A continuing program of research on

molecular ionization, dissociative ionization, and ionpair processes in diatomic and polyatomic molecules

has included the study of autoionization and predissociation phenomena, identification of Rydberg series and progressions, the determination of FranckCondon factors for direct ionization, accurate ionization threshold values and the derivation of bond

dissociation energies, electron affinities and heats of formation of ions and molecules.

Availability: The instruments are available at NBS to

qualified research workers following a short training

period. Proposed research projects require the approval of the Section Chief.

Literature:

[1] V. H. Dibeler, et al. Int. J. Mass Spectrometry

and Ion Phys. 11, 49 (1973).

[2] J. Chem. Phys. 44, 1271 (1966).

[3] K. E. McCulloh, J. Chem. Phy. 59, Oct. 1973.

Contact: Dr. Henry M. Rosenstock, Chief, Chemical

Dynamics Section, Chemistry Building, Room A145,

Phone 301-921-2792.

2550 2500 2450 500 AOO 300

CM-' CM-' RAMAN SPECTROSCOPY. Raman spectra showing changes

associated with order-disorder phase transitions (at ca. 205 K and ca. 113 K) in CsSH, lattice translations (30-200

cm-'), lattice librations (200-600 cm-') and SH- stretching

modes (ca. 2500 cm-').

RAMAN SPECTROSCOPY

The spectral features observed in Raman and infra- red spectroscopy allow qualitative and quantitative

identification of species and can be used to establish structure and measure dynamical interactions in molecular compounds and crystalline bodies. Raman

spectroscopy routinely studies the molecular motions

in the range 0 to 5000 cm-i. It investigates the scat- tering of electromagnetic waves (typically 400 to 700

nm) caused by the modulation of the optical polarizability of atoms and molecules created by their

internal vibrations, rotations, translations and a vari- ety of electronic processes (magnons, plasmons).

Capability: Laser sources are used in conjunction with

a double monochromator for spectral analysis of the

scattered light. The photoelectrically detected signal

is processed by either dc or photon rate techniques.

The spectrometer covers the range from 30,000 to 10,000 cm-i with a resolution of 0.25 cm-^. The lasers available are a He-Ne laser operating at 632.8 nm,

60 mW power, and an Ar+ ion laser operating principally at 488.0 or 514.5 nm, powers up to 5 watts. The Ar+ ion laser (which can produce over 1 watt in the UV lines) can be used in conjunction with a jet- stream dye laser to produce a continuously tunable

laser source covering the range from 400.0 to 700.0 nm. The instrument is equipped with a versatile sample chamber which allows a great variety of sample

types and scattering geometries to be selected. Equipment for temperature variation and matrix isolation is provided. The Raman laboratory is equipped with a dedicated minicomputer and associated peripheral

equipment which allows automated data acquisition

and "on-line" processing of Raman spectral data. Applications: Raman spectroscopy is a useful tool for the identification of molecular or ionic species. Struc- tures and force constants can be determined for

liquids, solids, and gases. Typical applications involve

the spectra of matrix isolated free radicals and molecules, lattice and molecular dynamics of polymers,

phase transitions in solids (including melting), studies of isomerism, vibrational and rotational studies in gases, investigation of stoichiometry in crystals and

disordered solids, and measurements of chemical

reaction products.

Availability: The instrument is available to qualifiev

research workers at NBS, following a training period

in its use. Proposed research projects require the approval of the instrument manager, or in special cases by a users committee.

Contact: Dr. Gregory J. Rosasco, Physicist, Solid State Materials Section, Materials Building, Room A165,

Phone 301-921-2780.
SURFACE

PROPERTIES

FACILITIES

ELECTRON PROBE MICROANALYZER.

ELECTRON PROBE

MICROANALYZER

The electron probe microanalyzer has the unique

function of qualitatively and quantitatively analyzing

microscopic regions of specimens, of 1-3 diameter, with regard to elemental composition. This is achieved by focusing a beam of electrons upon the

specimen surface, and analyzing the characteristic x-radiation emitted from the bombarded spot on the

specimen.

The function of localized analysis is complemented

by capabilities for area- and line-scanning, which

permit the simultaneous exploration of a microscopic

region.

The electron probe has been used for a wide range

of specimens, including lunar and terrestrial rocks,

alloys, ceramics, paper, and biological materials. Operational Characteristics: Specimens of up to 2.54 cm (1 inch) diameter can be analyzed. For quantitative analysis, specimens must be flat and electric in- sulators must be coated with a film of carbon or

metal. Facilities for specimen preparation are avail- able. All elements of atomic number above 4 can be

detected, and quantitative analysis is possible for elements of atomic number above 10. Limits of detection are typically in the order of 0.01%; the total sample mass analyzed is typically 10-"g. Accuracy of

quantitative analysis for major constituents is typically

2-3% relative.

Typical Applications: Study of inclusions, of corrosion

products on alloys of coating and paint layers, of particulate corrosion or pollution products, altered

coins, failures of solid-state microelectronics, manufacturing techniques of archaeological objects, distri- bution of elements in biological tissue (plant or

animal).

Availability: To trained operators only. Service using our own operators is available. Contact: Dr. Kurt F. J. Heinrich, Chief, Microanalysis

Section, Chemistry Building, Room A121, Phone 301-

921-2871.

ION PROBE

MICROANALYZER

The ion probe microanalyzer is a tool for qualitative

and semiquantitative elemental analysis of microscopic regions of solid specimens. The technique of ion probe microanalysis is based on the formation

of a focused beam of ions which bombards a microscopic region of the specimen. The area of impact of the primary beam is eroded by it, and secondary ions of the elements present in the specimen are emitted.

These ions are analyzed in a mass analyzer; the mass numbers of the ions indicate which elements are present, and the intensities of emission are related

to the concentrations of the elements forming sec- ondary ions. The capabilities of this instrument include trace analysis, isotope ratio measurement, and the detection

and analysis for elements of low atomic number, in- cluding hdyrogen. All these measurements can be

taken from a region a few micrometeres wide and a few tens of angstroms deep.

Operational Characteristics: Specimens of up to 2.54 cm (1 inch) diameter can be analyzed. The specimens

must be flat. Facilities for specimen preparation are

available. AM elements can be detected and analyzed

semiquantitatively. The sensitivity is highest for ele- ments of Croups I and II (e.g., sodium) where it is in the ppm range. The accuracy of isotope ratio measurements for major components is typically 2 to 3%.

Typical Applications: This is a novel instrument, and

present experience is limited. Lunar rocks, distribu- tion of impurities in semiconductors, surface impurities on irradiated materials, and trace element distri- , butions in glasses have been investigated. Preliminary

investigations of biological materials are very encouraging.

45
Availability: In view of the expense and complexity

of this instrument, access is given to trained operators only. Service by the NBS operator is available. Contact: Dr. Kurt F. J. Heinrich, Chief of Surface

Microanalysis Section, Chemistry Building, Room

A121, Phone 301-921-2871.

MOLECULAR BEAMFIELD EMISSION

MICROSCOPE

A molecular beam machine is combined with a field emission microscope, capable of operation down to

4.2 K, to observe deposition, surface migration, adsorption, displacement effects and catalysis in almost

molecular detail.

Capability: Surface studies may be made on any

metal or semiconductor capable of being used as a

field electron emission source. Included are such

metals as tungsten, molybdenum, rhenium, rhodium,

nickel, niobium, ruthenium, and many others. The

specific features of the apparatus are excellent control and quantitative measure of the deposition of gases on surfaces, the facile switching of gases in the beam, and the ease of control of the beam temperature. The temperature range available for the

emitter tip is from 4.2 K to the melting point of the

metal or semiconductor.

Applications: Fundamental studies and observations

of catalytic surfaces, or adsorption, of sticking probabilities, of adsorption-displacement, and of surface

reactions are possible with the apparatus.

Availability: To qualified research personnel on a cooperative basis. Prior arrangements must be made,

and only short term (one to two weeks) experiments

will be considered.

Literature:

[1] "Preparation of Contiguous Chemisorbed

Adiayers by Sequential Deposition and Sur- face Migration" Ralph Klein, Surface Science,

29, No. 1, pp. 309-316, January, 1972.

[2] "Second Layer Migration with Trapping on

First Layer Sites: Hydrogen, Nitrogen, and

Carbon Monoxide on Tungsten" Mordecai

Folman and Ralph Klein, Surface Science, 11, pp. 430-442, 1968.

[3] "The Deposition of Hydrogen Beams on

Tungsten" Ralph Klein, Surface Science, 11, pp. 227-241, 1968.

Contact: Dr. Ralph Klein, Senior Scientist, Physical

Chemistry Division, Chemistry Building, Room B248,

Phone 301-921-2161.

MOLECULAR

BEAM MACHINE

An ultrahigh vacuum, differentially pumped molecular beam machine for high precision work. At present

it uses alkali or alkali halide beams with surface

ionization detection.

Capability: Source is a resistively heated effusion cell. Detector can probe 6.5/xm perpendicular to the

beam axis, with a resolution of 0.02jLim. Ultimate vacuum is 10-" torr. Application: Primarily as a research tool for investi- gation of gas-surface interactions.

Availability: This equipment is being used presently on a longrange program concerned specifically with

measurement of van der Waal's forces. Availability is limited to very short-range problems of mutual in- terest in that field, with operation by Section staff. Contact: Dr. Ralph Klein, Senior Scientist, Physical

Chemistry Division, Chemistry Building, Room B248,

Phone 301-921-2161.

46
SURFACE ANALYSIS

FACILITY

ESCA and Auger spectrometers are available for the

quantitative or semiquantitative chemical analysis of surfaces and surface layers. Both spectrometers have

a sensitivity of a small fraction of a monolayer to most elements. In the case of ESCA, the presence

of a chemical shift is often used to determine the

valence state of surface species.

Capability: Ambient pressure is 10-" torr. Sample

size about 1 cm^. Depth sensitivity is of the order

of 10 A. Depth profile measurement using Ar ion

sputtering is possible.

Application: Wherever chemical analysis of surface

layers is desirable. In most cases, special sample

handling procedures are of importance to reduce

contamination effects.

Availability: These instruments are research tools being used extensively in ongoing research pro- grams. They are generally not available for analyses

of samples. However, in certain situations, where our

staff might become involved in a research problem,

the instrument could be made available. Special

training is necessary for operation of either instru- ment.

Contact: Dr. John T. Yates, Jr., Acting Chief, Surface

Process and Catalysis Section, Chemistry Building,

Room B250, Phone 301-921-2188.

Literature:

[1] S. H. and D. M. Hercules, Surface Characterization by Electron Spectroscopy for Chemical Analysis (ESCA), p. 307 in book Characterization of Solid Surfaces, Kane & Larrabee,

Plenum Pr., New York, 1974.

[2] C. C. Chang, Chemical Analysis by Auger

Electron Spectroscopy, ibid, p. 509.

[3] E. N. Sickafus, J. Vac. Sci. & Tech. 11, 299

(1974).

SURFACE AREA

ANALYZER

The Surface Area Analyzer provides a complete sys- tem for preconditioning and measuring both low and

high values of surface area by the classic BrunauerEmmett-Teller technique, employing krypton and

nitrogen as the absorbates in a metal system, in addition, pore size distribution can be obtained from

complete adsorption or desorption isotherms. Cal- culations can be made manually or with available computer programs.

Capability: The system is capable of measuring active surface areas as low as 100 cm-/g. The reproducibility

of the system using krypton is ± 3 percent for materials with surface areas of 200 cm^/g or greater,

having a total sample area of 500 cm^ or greater.

Using nitrogen, the reproducibility is ± 3 percent

for a total sample area of 5 m^ or greater. Special

sample holders are available, capable of accepting

planar materials having dimensions 1.5 x 1.5 x .05 cm.

Applications: The surface area and/or pore size dis- tribution of materials such as catalysts, gasket material, paper, plastics, foams, etc., may be deter- mined. The special sample holders for planar materials enable determination of surface properties

and physical tests on the same specimen.

Availability: To an qualified research worker after an

initial training period with Dr. E. L. Craminski. A

good knowledge of vacuum systems is necessary to operate the apparatus. Contact: Dr. E. L. Craminski, Polymer Stability and

Reactivity Section, Polymer Building, Room A369,

Phone 301-921-2923.

Scanning electron photomicrograph shows broken fibers and other characteristics of a paper specimen which affect the surface area of the specimen. A typical specimen measured by the SURFACE AREA ANALYZER.

47
X-RAY

FACILITIES

ROTATING

X-RAY ANODE

DIFFRACTION UNIT

Stationary anode X-ray tubes have been used for most

conventional X-ray diffraction generators. However,

since a large amount of heat energy is generated by

the electron beam bombardment on the anode, the

X-ray intensity is limited. The rotating anode tube can

give higher intensity X-rays because the water-cooled

anode is rotated at a high speed to distribute the

heat energy over the circumferential surface of the

anode.

Capability: The maximum operating conditions for

this unit are 60 kV and 100 mA. This produces X-rays

whose brilliance is 10 to 20 times greater than that

of the normal sealed X-ray tubes. This makes it possible to reduce the exposure time dramatically in the

photographic method, to scan rapidly with a counter,

or to study dynamic changes or transformations in the crystal structure.

Applications: Measurement of the long period in chain-folded polymer crystals. Crystallographic studies of paraffins; observations of phase changes in polymer and paraffin crystals; X-ray diffraction pat- terns from wet collagen; detection of small amounts

of crystalline impurities.

Availability: The use of this instrument by NBS re- search workers on problems of mutual interest can be arranged. It must be operated only under the

direct supervision of the scientist in charge of the

instrument.

Contact: Dr. Darreli H. Reneker, Chief of Structural Analysis and Standards Section, Polymer Building,

Room A209, Phone 301-921-3344.

Ti3 -8 -6 -4 -2 0

E-Ep (eV)

SOFT X-RAY SPECTROMETER. A comparison of the soft x-ray Mj spectruni (SXS) of Cu with ultraviolet (UPS) and

x-ray (XPS) photoemission and ion neutralization (INS) spectra.

SOFT X-RAY

SPECTROMETER

This spectrometer is a 2-meter, grazing incidence

instrument with a ruled glass grating, 30,000 lines per inch. It is equipped with an electron multiplier

detector and magnetic tape output for digital computer processing. Programs are available for data reduction and plotting of spectra. A spectral range

of approximately 2.5 to 80 nm can be covered but

as presently set, the grating cut-off is at about 4 nm.

Capability: Optimum specimen shape is a rod about

V*" dia. X 3" long but variations from this can be

used. Electron excitation of 2500 volts is used which

causes some heating of the specimen. The temperature can be controlled within limits and can be continuously monitored with a thermocouple on the

specimen. The maximum effective skin depth of material being analyzed is of the order of 4 to 100 nm,

depending on atomic number.

48
Applications: Chemical analysis for the light elements

down to lithium in atomic number (except oxygen

and nitrogen with the spectrometer as presently set); this application would be particularly useful when

associated with surface and shallow skin depth phenomena, such as the identification of boride, carbide,

and sulfide precipitates on a fracture surface, for ex- ample. Application to other types of metallurgical

phenomena such as detection of dezincification in brass and the reduction of iron oxide in the aluminizing of steel sheet; in the case of the higher atomic

number elements, transitions between outer electron

levels, and transitions from the valence band to outer

levels are observed. Valence band spectra as a function of the state of chemical combination; the bulk

of the work that has been done on this instrument has

been the study of valence band structure to obtain a better understanding of the principles of intermetallic compound formation and the electronic basis for their physical properties.

Availability: To any qualified NBS research worker.

Also, in appropriate situations the facility can be

made available to researchers from other government, education and industrial organizations.

Literature:

[1] A Soft X-Ray Spectrometer with improved

Drive, J. R. Cuthill, Rev. Sci. Inst. 41, 422

(1970).

[2] Improved Drive for Soft X-Ray Spectrometer,

NBS Tech. News Bull., October 1970, Vol.

54, No. 10, Page 231.

Contact: Dr. John R. Cuthill, Assistant Chief, Alloy

Physics Section, Materials Building, Room B-148,

Phone 301-921-2913.

THREE-CIRCLE

X-RAY DIFFRACTOMETER

materials scientists concerned with bonding, elec- tronic configurations, lattice and atomic vibrations,

coordination, valence states, and other properties.

Availability: On a selective basis when not required

for Crystallography Section programs. The instrument

must be operated by Section personnel and only

work of mutual interest can be undertaken.

Literature:

[1] inorganic Chemistry, 9, 2228 (1970).

[2] Crystal Structure Communications, 1, 247

(1972). Contact: Dr. Alan D. Mighell, Room B222, Materials

Building, Phone 301-921-2950.

THREE CIRCLE X-RAY DIFFRACTOMETER. Diagram of the cobalt imidizole complex cation in the compound Co (Im,) {NOo)i. The ellipsoids represent the root-mean-square amplitude of thermal oscillations of atoms.

Operating completely under computer control, the

instrument orients a single crystal in the x-ray beam

and records the diffracted intensity for each of several thousand reflections.

Capability: Data are collected at rates up to 1000 re- flections per day. Accuracy is indicated by the final R value obtained after least squares refinement. Typical values are in the range 3 to 5%.

Applications: Structural parameters, including bond

lengths, angles between bonds, and amplitudes of thermal vibrations are obtained. Precise three-dimensional diagrams can be drawn to scale. Diagrams of

this type are used by physicists, chemists and other

49
INDEX P^ge

Accelerated Weathering Laboratories 6 Acoustic Anechoic Chamber 4

Acoustic Reverberation Chamber 4

Acoustical Thermometer 25

Alloy Preparation Laboratory 21 Analytical Spectrophotometer 36

Antenna Measurement Facilities 5 Automatic Network Analyzer 14

Automation Laboratory 13

Central Computer Facilities 13

Chlorine Flux Monitor 18

Cobalt-60 Irradiation Facility 35

Concave Grating Spectrographs, 10.7m 37

Cryogenic Flow Research Facility 25

Czerny-Turner High-Dispersion Spectrograph . 37

Deadweight Force Calibration Machines 27

Electron Energy Loss Spectrometers for Gases . 38

Electron Probe Microanalyzer 45

Electron Van de Graaff Accelerator, 4 MeV ... 2

Electro-optical High Voltage Field Mapping

Systems 15

Far Infrared Spectroscopy 38

Filtered Neutron Beams 30

Fire Research Laboratory 19

Flame Emission Spectrometry with Repetitive

Optical Scanning 38

Flash Photolysis Resonance Fluorescence

Apparatus 39

Fluid Flow Measurement 28

Fluorine Combustion Calorimeter 10

Fourier Transform Nuclear Magnetic Resonance

Spectrometer 39

Gas Chromatograph-Mass Spectrometer System 40

High Pressure Generators 20

High Pressure Optical Fluorescence System ... 20

High Pressure Photoionization Mass

Spectrometer 40

High Pressure PVT Dilatometer 21 High Resolution Infrared Spectrometer 41 High Temperature Controlled-Atmosphere

Furnace 22

High Temperature Vaporization Laboratory ... 22

Hydrogen Liquefaction Facility 26

Inorganic Glasses: Preparation and Viscosity . . 23

Intermediate-Energy Standard Neutron Field (ISNF) 31 Ion Probe Microanalyzer 45

Isotope Ratio Mass Spectrometers 41 Isotope Separator Laboratory 31 Laser Materials Facility 23

Liquefied Natural Gas Flow Facility 26

Linear Electron Accelerator (LINAC) 2

50

*U.S. GOVERNMENT PRINTING OFFICE: 1976 210-801/219 1-3

Page

Low Temperature Adiabatic Calorimeter 10

Machine Tools, Numerically Controlled 26

Mercury Manometer 24

Microcalorimetry 11 Microwave Spectroscopy Facility 41 Millisecond High Temperature Thermophysical

Measurements 24

Molecular Beam-Field Emission Microscope . . 46

Molecular Beam Machine 46

Mossbauer Spectroscopy of Metals 42

Multichannel Flame Spectrometer 42

Neutron Diffractometers 32

Neutron Radiography Facility 33

Neutron Scattering Spectrometer 33

Non-Magnetic Facility 15

Nuclear Irradiation Facilities 34

Nuclear Magnetic Resonance Spectroscopy ... 43

Nuclear Reactor 30

Photoionization Spectrometry 43

Platinum-lined Adiabatic Solution Calorimeter. 12

Plumbing Research Laboratory 7

Positive-Ion Van de Graaff Accelerator, 3MeV . 3 Precision Humidity Measurement 18

Raman Spectroscopy 44

Reactance Bridge for Power Loss Measurement 16

Rooftop Antenna Test Facility 6

Rotating X-Ray Anode Diffraction Unit 48

Rotating, Platinum-lined, Adiabatic Bomb

Calorimeter 12

Scanning Electron Microscope 16

Soft X-Ray Spectrometer 48

Special Announcements on WWV/WWVH ... 36

Structures Laboratories 7 Surface Analysis Facility 47

Surface Area Analyzer 47

Synchroton Ultraviolet Radiation Facility

(SURF) 3 Thermal Engineering Laboratories 8

Thermographic Equipment 9 Three-Circle X-Ray Diffractometer 49

Three-Dimensional Precision Measurement ... 28

Time-of-Flight Neutron Spectrometers 34

Transmission Electron Microscope, 200 kV . . . . 17

Universal Testing Machine, Twelve Million

Pound-Force 29

Wind Tunnel for Unsteady Flows 29

WWVL VLF Broadcast Station 35

Photo

A. B. National Bureau of Standards laboratories at Boulder, Colorado.

C. The 550 acre NBS-Caithersburg site seen from the air. The seven General Purpose Laboratories and the 11 -story Administration Building are in the center of the picture. D. The Administration Building, seen from the courtyard

of the NBS Library.

E. One of the seven General Purpose Laboratories is seen

in the background. 385' x 705', the building contains 348

laboratories and offices.

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