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' N B S

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NAT'L INST OF STAND & TECH NBS SPECIAL PUBLICATION 413

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

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SPECIAL TECHNICAL FACILITIES

at the National Bureau of Standards
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.
al ijurs^d oi SL'indards

1 1 1975 "Special

Technical Facilities

at the

National Bureau of Standards

H. L. Mason and Iris M. Lloyd

Editors

U.S. DEPARTMENT OF COMMERCE, Frederick B. Dent, Secretary

NATIONAL BUREAU OF STANDARDS, Richard W. Roberts, Director

Issued January, 1975

i
National Bureau of Standards Special Publication 413

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

(Jan. 1975)

U.S. GOVERNMENT PRINTING OFFICE WASHINGTON; 1975

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

(Order by SD Catalog No. C13. 11 :413/ ) Price 81.10
FOREWORD

The National Bureau of Standards is one of the world's great

physical science laboratories. In many cases our equipment

and facilities are unique national resources, ready to play a

vital role in solving urgent problems of the day. For example,

our high flux nuclear reactor is one of the major research

reactors in the nation, and is used daily in projects ranging

from abstract nuclear theory to analysis of food contaminants.

But equipment cannot be used unless its existence and

capabilities are known, so we have prepared this catalog to inform scientists—both at NBS and at other institutions—as to what is available at NBS for cooperative use.

Richard W. Roberts

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.

iii
TABLE OF CONTENTS

Page

INTRODUCTION 1

ACCELERATORS

Electron Van de Graaff Accelerator 2 Linear Electron Accelerator 2

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

ACOUSTIC FACILITIES

Acoustic Anechoic Chamber 4

Acoustic Reverberation Chamber 4

ANTENNAS

Antenna Anechoic Chamber 5 Antenna Field Strength Facilities 5 Rooftop Antenna Range 6

BUILDING RESEARCH FACILITIES

Accelerated Weathering Facility 6 Plumbing Research Laboratory 7

Structures Laboratory 7 Thermal Engineering Laboratories 8

CALORIMETERS

Fluorine Combustion Calorimeter 9

Low-Temperature Adiabatic Calorimeter 9 Microcalorimetry 10

Platinum-lined Adiabatic Solution Calorimeter . . 10

Rotating, Platinum-lined, Adiabatic Bomb

Calorimeter 11

COMPUTER

Central Computer Facility 11

ELECTRICAL MEASUREMENTS FACILITIES

Automatic Network Analyzer 12

Page

Electro-optical H\gh Voltage Field Mapping

Systems 13

Non-Magnetic Facility 13 Reactance Bridge for Power Loss Measurement . 14

ELECTRON MICROSCOPES

Scanning Electron Microscope 15 Transmission Electron Microscope 15

ENVIRONMENTAL FACILITIES

Precision Humidity Measurement 16

Sulfur Dioxide Pollution Monitor 16

FIRE RESEARCH

Fire Research Laboratory 17

HIGH PRESSURE FACILITIES

High Pressure Generators 18

High Pressure Optical Fluorescence System .... 18

High Pressure PVT Dilatometer 19

HIGH TEMPERATURE FACILITIES

Alloy Preparation Laboratory 19

High Temperature Controlled-Atmosphere

Furnace 20

High Temperature Vaporization Laboratory .... 20

Inorganic Glasses Laboratory 21

Laser Materials Facility 21 Millisecond High Temperature Thermophysical

Measurement 22

LOW PRESSURE FACILITY

Mercury Manometer 22

LOW TEMPERATURE FACILITIES

Acoustical Thermometer 23

iv
Page

Cryogenic Flow Research Facility 23

Hydrogen Liquefaction Facility 24

Liquefied Natural Gas Flow Facility 24

Nuclear Orientation Cryostat 24

MACHINE TOOLS, NUMERICALLY CONTROLLED

Machine Tools, Numerically Controlled 25

MECHANICAL MEASUREMENT FACILITIES

Deadweight Force Calibration Machines 25

Fluid Flow Measurement 26

Three-Dimensional Precision Measurement .... 27

Universal Testing Machine, Twelve Million

Pound-Force 27

Wind Tunnel for Unsteady Flow 28

NUCLEAR REACTOR AND ASSOCIATED

FACILITIES

Nuclear Reactor 28

Filtered Neutron Beams 29

Intermediate-Energy Standard Neutron Field ... 29

Isotope Separator Laboratory 29

Monoenergetic Neutron Beam Facilities 30

Neutron Diffractometers 30

Neutron Radiography Facility 31 Neutron Scattering Spectrometer 31 Nuclear Irradiation Facilities 32

Time-of-Flight Neutron Spectrometers 32

RADIOACTIVE SOURCE

Cobalt-60 Irradiation Facility 33

RADIO STATIONS

WWVL VLF Broadcast Station 33

Special Announcements on WWV/WWVH 34

SPECTROSCOPY FACILITIES

Analytical Spectrophometer 34

Page

Concave Grating Spectrographs 35

Czerny-Turner High-Dispersion Spectrograph . . 35

Electron Energy Loss Spectrometers for Gases . . 36

Far Infrared Spectroscopy 36

Flame Emission Spectrometer with Repetitive

Optical Scanning 36

Flash Photolysis Resonance Fluorescence

Apparatus 37

Fourier Transform Nuclear Magnetic

Resonance Spectrometer 37

Gas Chromatograph-Mass Spectrometer System . 38

High Pressure Photoionization Mass

Spectrometer 38

High Resolution Infrared Spectrometer 39

Isotope Ratio Mass Spectrometers 39

Microwave Spectroscopy Facility 39

Mossbauer Spectroscopy of Metals 40

Multichannel Flame Spectrometer 40

Nuclear Magnetic Resonance Spectroscopy .... 41 Photoionization Spectrometry 41 Raman Spectroscopy 42

SURFACE PROPERTIES FACILITIES

Electron Probe Microanalyzer 43

Ion Probe Microanalyzer 43

Molecular Beam-Field Emission Microscope .... 44

Molecular Beam Machine 44

Surface Area Analyzer 45

Surface Ionization Analyzer 45

X-RAY FACILITIES

Rotating Anode X-Ray Diffraction Unit 46

Soft X-Ray Spectrometer 46

Three-Circle X-Ray Diffractometer 47

INDEX 49

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, ail 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 LJ.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. Call, 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 8159, Phone 301/921-2587.

Information on automatic data processing equipment and standards—contact Miss M. R. Fox, Chief of Computer Information, 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 10 -' 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. J. W. Motz, Chief of 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: 80 kilowatts, average. CURRENT: 0.8 milliamperes, average

3.5 amperes, peak (short pulse operation).

REPETITION RATE: variable to 720 pps. PULSE LENGTH: 0.001 to 6 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: three, 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.

POSITIVE-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.

ENERCY: 0.8 to 3.0 MeV.

BEAM INTENSITY: 1 to 200/^A.

Analyzed Beam:

ENERCY: protons—0.8 to 3.0 MeV; deuterons—

0.8 to 2.8 MeV.

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

ENERCY 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 is being developed based on a D.C. 6024/5 computer.

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

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 Section, Radiation Physics Building, Room B119, Phone t 301-921-2677. I

SYNCHROTRON

ULTRAVIOLET RADIATION

FACILITY (SURF)

Synchrotron radiation in the far ultraviolet is highly

collimated, 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 Synchroton Ultraviolet Radiation

Facility (SURF) is now in the process of being converted into a storage ring. Initial injection has been

achieved and full operation is expected by the end of 1974. With a microtron injector the storage ring is ex- pected to accelerate a 50 mA beam to a maximum

energy of 240 MeV. The expected intensity in the

region 600 A to 1200 A is 4 X 10'^ photons per second per milliradian of orbit for an instrumental

resolution of /\k/k= 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

ANECHOIC 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 40 Hz to at least 63 kHz. Upper

bounds for wide-band ambient noise are about 30 dB

re 20 /xN/m- 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: Walter Koidan, Sound Bidg., Room B140,

Phone 301-921-3607.

ACOUSTIC

REVERBERATION

CHAMBER

The chamber is a vibration-isolated, shell-within-shell 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 50 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 ixN/mfor C-weighting and about 36 dB with vanes rotating

at 5 rpm. The reverberation time T,;„ (60 decibel

decay) is approximately 18 seconds at 100 Hz and

about 5 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: Raymond D. Berendt, Sound Building, Room

A117, Phone 301-921-3607.
ANTENNAS

ANTENNA FIELD STRENGTH FACILITIES. Movable towers used for evaluating horn and dish antennas.

ANTENNA

ANECHOIC CHAMBER

A microwave darkroom which simulates free-space

measurement conditions for antenna design and

measurement. The outside dimensions are 20' long,

10' wide and 10' high. Nominal inside dimensions

are 17' long, 7' wide, and 7' high. Access is through

a 3' wide by 6V2' high door.

Capability: The minimum specified frequency for the

anechoic material is 500 MHz. The maximum ab- sorber reflectivity is —20 dB at 500 MHz and decreases to —50 dB at 9 GHz. The 16' transmission

path between test antennas determines the antenna

aperture sizes which can be used. If the commonly

used requirement of antenna separation of 2(d, +

do)/X is applied and if the antenna dimensions of d, and d. are assumed to be equal then the maximum

antenna aperture dimensions are 8 wavelengths for each antenna. Use of the facility can be made with

reduced accuracy from 100 MHz to 500 MHz.

Applications: The anechoic chamber is located adja- cent to an automatic network analyzer which provides

for rf signal generation and detection under computer control. This provides for the measurement of antenna characteristics such as complex reflection (impedance) and transmission coefficients over the

frequency range of 0.1 to 18 GHz. Rigid coaxial cable

for frequencies to 18 GHz connect each end of the anechoic chamber back to the automatic network

analyzer. Data output is obtained on a high speed

electrostatic printer-plotter, or may be viewed as a polar plot or rectangular plot on oscilloscopes.

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: W. E. Little, Program Chief, Automatic Net- work Analyzer Applications, Radio Building, Room

4633, NBS Boulder, Colo. 80302, Phone 303-499-1000

ext. 3658.

ANTENNA FIELD

STRENGTH FACILITIES

Capabilities: 1) Measuring gain on horn and dish an- tennas in the frequency range 500MHz to 75GHz, using

two 20-foot towers capable of moving 200 feet apart on

high-accuracy rails. 2) Scanning near-field radiation patterns and measuring gain in the frequency range 1 to 75GHz. 3) Measuring field strength and calibrating antennas and field strength intensity meters in the

frequency range 10Hz to 1GHz. 4) Evaluation of elec- tromagnetic hazard probes used for checking leakage

fields, e.g. from microwave ovens or high power

transmitters.

Applications: Measurement of antenna patterns and

gains at frequencies from 10Hz to 75GHz.

Availability: To any qualified NBS research workers,

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

other Federal organizations can gain access to the

facility.

Literature:

[1] Accurate Measurement of Antenna Gain and

Polarization at Reduced Distances by an Extrapolation

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.

[2] Calibration Principles and Procedures for Field Strength Meters, H. E. Taggart and J. L. Workman,

Nat. Bur. Stand. (U.S.) Tech. Note 370 (Mar. 1969).

[3] D. M. Kerns, "Correction of near-field antenna

5
measurements made with an arbitrary but known

measure antenna," Electron. Lett., vol. 6, pp. 346-347,

May 1970.

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

Section, Radio Building, Room 4074A, NBS Boulder,

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

ROOFTOP

ANTENNA RANGE

The rooftop antenna range is located on the upper

flat portion of the roof above Wing 6 of the Radio

Building.

Capability: This rooftop antenna range was built to provide a means for antenna design and measure- ment for antennas too physically large or used at too low a frequency to be measured in the anechoic

chamber. Two rigid coaxial rf cables and a multi- conductor intercom and power cable connect to the automatic network analyzer in the laboratory below.

The automatic network analyzer provides 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 later equipment is not pres- ently dedicated for use with the rooftop antenna

range it is available for use from other 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: W. E. Little, Program Chief, Automatic Net- work Analyzer Applications, Radio Building, Room

4633, NBS Boulder, Colo. 80302, Phone 303-499-1000

ext. 3658.

BUILDING

RESEARCH

FACILITIES

ACCELERATED WEATHERING LABORATORIES. Compressed \ air gun for shooting ice spheres to simulate hail damage \ to building materials and systems. \ ACCELERATED

WEATHERING i 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 staj tions throughout the United States and Puerto Rico

provide a diversity of natural weathering conditions.

| Capability: Radiant-energy sources of the accelerated I test machines include single and twin carbon arcs, a j fluorescent sunlamp/black-light unit, and both water i and air-cooled xenon arcs. Monitoring is by dosi- meters, radiometers, or actinometers. Some machines i 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 j; a small spread-of-flame apparatus. A compressed-air ; gun fires ice spheres up to IVi inches diameter

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

Applications: Comparative studies of structural mate- I

rials, coatings, claddings, and composites; identifica- i

6

i
tion of relatively detrimental weathering 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] S. H. Greenfeld, Hail resistance of roofing

products, Nat. Bur. Stand. (U.S.), BIdg. Sci. Ser. 23 (Aug. 1969)

[2] L. F. Skoda, Performance of residential siding

materials, NBS Report 10805 for Naval Facilities Engineering Command (1972)

[3] J. R. Wright and V. E. Cray, Measurement of photochemical degradation in rigid poly

(vinyl chloride), Conf. Supp. No. 1, London,

14-16 June 1965, Plastics Institute Trans. Contact: Robert C. Mathey, Assistant Chief of Materials and Composites Section, Building Research

Building, Room B340, 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 sys- tems.

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, 1972, pp 30-

31.

Contact: Dr. L. S. Calowin, Chief of the Building Service Systems Section, 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

I 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

I 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 machine has adequate clearance for testing an 8-ft. high,

I 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 type and optionally printed on teletypewriters.

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, F. Y. and Somes, N. F., Structural Per- formance Evaluation of Innovative Building

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

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 devel- opment of standard test methods for freezers, coolers, refrigerated spaces or vehicles, heated enclosures,

air conditioning systems or large components, heating 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

speciments 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).

Availability: To any qualified guest worker, to the ex- tent consistent with NBS requirements; to other Government agencies on request.

Literature:

[1] Anthony, R. B., National Bureau of Standards

and Environmental Research, ASHRAE J., January 1967, pp. 75-88.

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

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

Contact: Frank J. Powell, Chief of Thermal Engineering Systems Section, Building Research Building,

Room B104, Phone 301-921-3501.

8
CALORIMETERS

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

equipment.

FLUORINE 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 10-'' micrometres

mercury to 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.

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- mention and the procedures of operation, use of this

facility is limited to qualified members of the NBS

staff or scientists, after specific training of perhaps

two months. The facility may be used indirectly

through cooperative or contractual research agree- ments.

Contact: Dr. C. T. Armstrong, Chief of Thermochemistry 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 round-the-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 ac- curacy scanning mode is being considered for alter- native 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; sensitive 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 per- sonnel in accord with agreement.

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 Dielectric and Thermal Properties Section, Polymer

Building, Room B318, Phone 301-921-2748.

9
MICROCALORIMETRY

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

±10;mW) 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. Measure- ment 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] R. N. Goldberg, R. L. Nuttall, E. J. Prosen, and

A. P. Brunetti, NBS Report No. 10 437 (1971).

Contact: Dr. G. T. Armstrong, Chief, Thermochemistry

Section, Chemistry Building, Room B350, Phone 301-

921-2131.

0 100 ' 200 300

501 '

I

' r

' rTypical 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 C,, around

240 K.

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.

10
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 scientists, after specific training of per- haps two months. The facility may be used indirectly

through cooperative or contractual research agree- ments.

Literature: Prosen, E. J., and Kilday, M. V., J. Res. Nat.

Bur. Stand. (U.S.) Ilk, 179 (1974).

Contact: Dr. C. T. Armstrong, Chief of Thermochemistry 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 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 rota- tion of the calorimeter. Amounts of sample are nor- mally such as to cause 2500 J to be liberated as heat

in the reaction. Under optimum conditions, the en- ergy of reaction can be determined between 298 K and 323 K with a precision of better than 0.005%.

Calorimeter temperatures are measured potentiometrically with a platinum resistance thermometer as the sensor. The adiabatic shield temperature is controlled automatically to eliminate heat transfer to the calorimeter from its environment. Determination

of the amount and products of reaction can be deter- mined by measurement of the amount of CO^ gas formed, and by analysis of aqueous solution constit- uents.

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- mention 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 per- haps two months. The facility may be used indirectly

through cooperative or contractual research agree- ments.

Contact: Dr. G. T. Armstrong, Chief of Thermochemistry Section, Chemistry Building, Room B350, Phone

301-921-2131.

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 environment which provides for a variety of user options. Access to the main computer is provided to both onsite users and those at remote terminals connected

via telecommunications. Software support includes

FORTRAN, COBOL, ALGOL, FLOWGEN (Automatic

Flow Chart Generation), XBASIC, 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. Other

drum 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 Vlll-C Tape Drives (200, 556, 800

CPI), two nine-track Vlll-C Tape Drives (800 CP!), one

758 high-speed Printer, one 1403 off-line Printer, one

1004 Reader/ Printer, one 1004 Card Punch, one highspeed Card Punch (300 CPM), and one high-speed

Card Reader (900 CPM).

11
Graphics Facilities: The Central Computer Facility

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

(or hard copv) 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 S-C 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 In- formation Interchange (ASCII). This provides character printing sufficient to handle scientific documents

at the normal level of complexity in notation, in- cluding half-line spacing for superscripts and subscripts, a repertory of Greek alphabetic characters and an assortment of special signs and symbols. Offline 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 held 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).

ELECTRICAL

MEASUREMENTS

FACILITIES

NON-MAGNETIC FACILITY. The probe shown in the fore- ground travels along the axis of the 1 000-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

12
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: W. E. Little, Program Chief, Automatic Net- work Analyzer Applications, Radio Building, Room

4633, NBS Boulder, Colo. 80302, Phone 303-499-1000

ext. 3658.

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 electro-optical systems include their freedom from electromagnetic 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^s with durations up to 10ju,s, repetition rates to 4 pulses per minute, measurement accuracy within

±1%.

2) DC Operation: from 0 to 100 kV, measure- ment accuracy 0.01%.

3) AC Operation: from 0 to 50 kV rms, from 40

to 200 Hz, measurement accuracy to 0.01%.

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 dis- tributions in selected insulating dielectrics; for vis- ualization 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 required to avoid conflict with in-house NBS re- search, 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.

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

Contact: 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

13
1

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 build- ing 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 preci- sion 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

building 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 pro- ton 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).

[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, Non-Magnetic Building, Phone

301-921-2007.

REACTANCE BRIDGE

FOR POWER LOSS

MEASUREMENT

A typical high voltage inductor or shunt reactor on a power transmission line has a reactive power rating

of 100 megavolt-amperes and a power loss of about

220 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 capacitance 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 standard 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

SOjuF. 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 for 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: Oskars Petersons, Chief of High Voltage

Measurements Section, Metrology Building, Room

B344, Phone: 301-921-3121.

14
ELECTRON

MICROSCOPES

Photomicrograph of a stainless steel powder, magnified 600 times. The large depth of focus of the SCANNING

ELECTRON 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 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 100,000x. Electron beam

of about 10 nm (100A) diameter is driven across speci- men, 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 avail- able. 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 termoiite; 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 VV. Ruff, Jr., Chief of Lattice Defects and Microstructures Section, Materials Building,

Room B118, Phone 301-921-2991.

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. Compared to conventional transmission electron microscopes (100 kV),

specimens which are 70% thicker can be examined.

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 electro- 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

0.7 nm (7 A) and maximum magnification of 150,000x. Data recorded on 31/4 x 4 inch glass photographic

plates.

Applications: Examination of the surface regions of various ceramic materials after abrasive and smoothsliding 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 ce- mented carbides; determination of stacking fault

15
energy as a function of temperature in Ag-Sn and AuSn alloys; analysis of deformation modes in superplastic Al-base alloys; study of deformation and cor- rosion 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.

ENVIRONMENTAL

FACILITIES

SULFUR DIOXIDE POLLUTION MONITOR.

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 ac- curate humidity measurements.

Capability: Gas flows up to 150 cubic decimetres per minute. Ambient temperatures from -1-65 to —75°C.

Mixing ratios from about 150 to 1 X 50 g/kg (1.5 X 10' to 0.01 ppm). Dew point of -h65°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 I

percent. 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; evaluation and testing of such sensors as carbon film, alu- minum oxide, crystal array, lithium chloride, barium

fioride; 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)

Contact: Arnold Wexler, Chief, Humidity Section. Physics Building, Room B356, Phone 301-921-2794.

SULFUR DIOXIDE

POLLUTION MONITOR

Sulfur dioxide, released in air by burning sulfur-con- taining coal and oil, is one of the most common air pollutants. This detector, based on measuring the in- tensity of the fluorescence excited by a Zn or Cd

light source, is capable of continuously monitoring

sulfur dioxide in air over a wide range of concentration. The procedure is rapid, simple in operation,

and is specific to sulfur dioxide.

Capability: The device developed at NBS can measure SO^ in air from 1500 parts per million down to a few parts per billion. The response is linear over this wide range of concentration. The detector responds

specifically to sulfur dioxide and is free from inter- ference with water and other common gases present

in air. In the ppm range the photoelectron signal can be amplified and displayed on a recorder. In the ppb range, however, a few minutes integration of the

photoelectron flux from the photomultiplier tube is necessary.

Applications: The measurement of SO,, in smokestack

effluent and in ambient air. Quick calibration of cylinders containing standard mixtures of SO, and air.

Availability: To any qualified NBS research worker

after an initial training period with Dr. Frederick P. Schwarz. In appropriate instances individual research workers from other Federal organizations can gain access to the facility.

16
Literature: Hideo Okabe, P. L. Splitstone, and J. J. Bells, Ambient and Source SO^, Detector Based on a Fluorescence Method, J. Air Pollution Control Assoc.

23, 514 (1973).

Contact: Dr. Hideo Okabe, Consultant to the Physical

Chemistry Division, Chemistry Building, Room A247,

Phone 301-921-2719.

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 -f-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. I. A. Benjamin, Fire Technology Division,

Technology Building, Room B64, Phone 301-921-

3255.

A room fire test in fhe FIRE RESEARCH LABORATORY.

17
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:

MAXIMUM

PRESSURE

USABLE

VOLUME

ELECTRICAL LEADS

PRESSURE CAGE

TRANSMITTING

FLUID

System I 26 kbar 2600 (MPa)

1 9mm diameter X 100mm length 4

manganin

System II 40 kbar

(4000 MPa)

10mm diameter X 10mm length

1

ram force

pentane mixtures pentane mixtures,

also soft solids

Application: System I 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 Rj-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 pressure

cell, but with minor modification can be used in any

pressure vessel which has optical access.

Capability: Quantitative pressure determinations are made to 200 kbar with an accuracy in the range of

5 percent. Temperature capability to 300°C is also

available, but the accuracy in the pressure measure- ment is significantly reduced at this temperature.

Applications: Characterization of phenomena induced

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 pres- sure distribution in various pressure transmitting

media.

Availability: On a selective basis when not required

for Crystallography Section programs. The system

must be operated by Section personnel and only

work of mutual interest can be undertaken.

18
Literature:

[1] Science 176, 284 (1972)

[2] Rev. Sci. Instr. 44, 1 (1973)

Contact: Dr. G. 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 column

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 Rheology and Mechanical 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, Rheology Section, Poly- mer Building, Room B330, Phone 301-921-2116.

HIGH TEMPERATURE

FACILITIES

Levltation 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 melter; electron- beam evaporator; induction and resistance melting

and casting furnaces; heat-treating furnaces; cold- working equipment for rolling, swaging, and drawing.

Applications: High purity iron ingot with 1.194 ±

0.004% carbon; homogeneous ingot of magnesiumzinc; 200-mesh lead-indium powders.

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.

19
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 thick tungsten sheet; these are enclosed 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 characj teristics—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 j 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- i 2801. i

1 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 spec- trometric 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 vaporization 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. 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.

20
Contact: Dr. T. D. Coyle, Chief, inorganic Chemistry

Section, Materials Building, Room A329, Phone 301-

921-2847.

INORGANIC GLASSES

LABORATORY

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 10- to lO'"' 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 moid 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 soda-limesilica glass, are measured primarily by fiber elongation procedures.

Applications: Production of small lots of optical glass.

Synthesis of the glassy coal slag produced in magnetohydrodynamic 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 10i"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 neodymium-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 TEMqo mode with an aperture of about 2.5 mm in diameter. The spatial beam profile at 5 m from the oscillator approximates a Gaussian dis- tribution. The output energy is reproducible to within

±2%. The facility with one amplifier produces 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 modelocking.

Applications: This facility may be used to measure

extrinsic and intrinsic bulk damage thresholds and

surface damage thresholds. Whenever intrinsic damage arises from self-focusing, procedures exist for the

identification of the dominant mechanisms, such as the thermal 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.

21
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 Classes," 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 indi- rectly 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 be- tween the crowns and carefully located capacitance

electrodes.

Capability: Optimum relative accuracy of a single pressure measurement within 2 X lO '^ 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

1 X 10 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).

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.

Contact: Dr. Leslie A. Cuiidner, Project Leader, Gas

Thermometry, Room A05, Physics Building, Phone

301-921-2076.

22
LIQUEFIED NATURAL CAS 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 indicat- ing 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 miilikelvins. The facility has

operated at temperatures between 2.3 K and 27 K. Currently a laser interferometer is being installed to permit the measurement of acoustical wavelengths.

Auxiliary equipment permits the potentiometric meas- urement 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, G. 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 13^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 pro- vided.

Literature:

[1] NBS Tech. News Bull., August 1970, Vol. 54, No. 8, pages 167-169.

[2] NBS Tech. Note 606 "Cryogenic Flow Research Facility Provisional Accuracy State- ment" July 1971.

[3] J. A. Brennan, et al., Tech. Note 624, "An

Evaluation of Several Cryogenic Turbine

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

Contact: R. S. Collier, Act. Chief, Cryogenic Metrology Section, Cryogenics Building, Room 1108, NBS

Boulder, Colo. 80302, Phone 303-499-1000 ext. 3333.

23
HYDROGEN LIQUEFACTION

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 10''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 LNC. It also provides the

opportunity to develop new methods of measure- ment for LNC 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 sec- ond 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 pro- vided.

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

12-13; 1972, pages 15-16.

Contact: R. S. Collier, Act. Chief, Cryogenic Metrology Section, Cryogenics Building, Room 1108, NBS

Boulder, Colo. 80302, Phone 303-449-1000 ext. 3333.

NUCLEAR ORIENTATION

CRYOSTAT

This apparatus for the study of radioactive nuclei will cool paramagnetic salts or ferromagnetic materials to the few-millikelvin temperature range, in order to permit an ordering of the nuclear spins by hyperfine

interactions. The angular distribution of radiations ac- companying radioactive decay can then be used to study the decay process, the nuclear states involved, or the hyperfine interactions.

Capability: Elements difficult to orient otherwise can be implanted in ferromagnetic foils with an avail- able high-resolution isotope separator. Beta particles, conversion electrons, or low energy gamma rays are observed with an internal counter with an energy

resolution of less than 5 keV. Complex gamma-ray

spectra can be studied with two external Ge(Li) detectors. A computer-based pulse height analysis sys- tem is used for simultaneous data reduction for the three detectors.

Availability: Cooperative research not in conflict with

the present use of the system is invited on an indi- vidual basis.

Literature: A. T. Hirshfeld and D. D. Hoppes, Transition Mixing Ratios Determined from a Study of the

Electron and Gamma-Ray Distributions from Oriented

i-'-lr, Phys. Rev. C2, no. 6, 2341-9, Dec. 1970.

Contact: Dr. R. W. Hayward, Nuclear Spectroscopy

Section, Radiation Physics Building, Room C112,

Phone 301-921-2651.

24
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 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-station

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 ASCIIdSO) 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 travel offers lin- ear and circular interpolation while the vertical travel

is point-to-point. Instrument Shops Division 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. Ail 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 horizontal 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 (not yet purchased by ISD) are available for non-contacting measurements.

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

Phone 301-921-2439.

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:

Units of Maximum load Minimum load intermediate loads 500 Ibf 10 Ibf 5 Ibf 6100 Ibf 200 Ibf 100 Ibf (3050 kgf) (100 kgf) (50 kgf) 25,300 Ibf 400 Ibf 100 Ibf (11,500 kgf) (500 kgf) (500 kgf) 112,000 Ibf 300 Ibf 1000 Ibf 300,000 Ibf 10,000 Ibf (note 1) 1,000,000 Ibf 50,000 Ibf 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 cal- ibration of specific instruments on a fee basis can be

made and scheduled according to current work loads.

25
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.

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-2) 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 volume.

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 lO*'. 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 10-'' to 6.3 X 10-^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.

26
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

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 pro- duction.

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, ]. A., Use of a microscope as a non-contacting microdisplacement device. Rev. Sci.

Instr. 42, 1378 (1971)

Contact: Dr. J. A. Simpson, Deputy Chief, Optical

Physics Division, Metrology Building, Room B322,

Phone 301-921-2171.

UNIVERSAL TESTING

MACHINE, TWELVE

MILLION POUND-FORCE

This hydraulically 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

(over central 40 feet) Transverse bending

moment

(over central 40 feet) Uniform bearing

Tensile force on anchor

bolts

12,500,000 Ibf-ft 20,000,000 Ibf-ft

467,000 Ibf-ft/ft of width

750,000 Ibf-ft/ft of width 940 lbf/in2

150,000 Ibf/bolt

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 readout

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.

27
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. 274-5 (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 simulating 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. Plan view of the NBS reactor showing

beam ports, pneumatic tubes, and vertical thimbles. 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

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

28
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 re- maining facilities listed above are available for suit- able 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 neutrons 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 neutrons with energies below 100 keV. Much of the neutron dose, however, comes from 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.

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: Proposals are encouraged from NBS,

other-agency, and university scientists.

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

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

759 (Mar. 1973).

Contacts: Dr. Charles D. Bowman, Chief, Nuclear Sci- ences Division, Radiation Physics, Room B-117, 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 sys- tem, which is operated in the thermal column of the

NBS reactor, 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/cmUniformity 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. Crundl, 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 sent through an electrostatic lens and a 90°-sector magnet to a dispersion and target

chamber.

29
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

contamination-free transport from radio-chemistry

laboratory.

Availability: By prior arrangement.

Literature:

[1] NBS Tech. News Bull. Nov. 1968, p. 239.

[2] Landgrebe, A. R., Mann, W. B., and Schima,

F. J. The Distribution of 70-kV Praseodymium

Ions in Iron Foil and a Technique for Re- moving Thin Layers of Iron, Int. J. Appl. Rad. and Isotopes, 1970, 21, pp. 169-171.

Contact: Dr. W. B. Mann, Deputy Chief, Applied Radiation Division, Radiation Physics Building, Room

C118, Phone 301-921-2668.

MONOENERGETIC

NEUTRON BEAM

FACILITIES

The through tubes of the NBS reactor permit the es- tablishment of facilities for production of monoenergetic neutron beams in the keV region. Thick slugs

of scandium, iron or silicon when inserted into the

reactor through tubes block out all neutrons except

those at a particular energy where the cross section

is nearly zero. These energies are 2 keV for scandium,

25 for iron and 144 for silicon. These low cross sections, which are referred to as "windows," permit

neutrons only of that energy to pass.

Capability:

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 j Applications: Calibration of neutron dosimeters in the ! keV range, measurement of standard neutron cross sections in intense continuous beams, keV neutron j capture, gamma ray spectroscopy, keV fission physics, i

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.

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

Division, Radiation Physics Building, Room B117,

Phone 301-921-2234.

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 avail- able 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

0.9A 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 4K 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.

30
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.

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 10'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 (convertors include gadolinium metal and scintillators) with films that provide

radiographs with total exposures from 5 x lO'n/cmto 10"n/cm-, 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/xm 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, -^''U and -^*U, 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: NBS Reactor: Summary of Activities, Oct. 1971-

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

758 (Mar. 1973).

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

31
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).

Contact: Dr. Robert Carter, Chief, Reactor Radiation

Division, Materials 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 Vh

inches, and seven vertical reflector thimbles with AVi

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 accompanied 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 A137, 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-fiight 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-'). 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 collec- tion 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 be- tween 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.

32
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.

RADIOACTIVE

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 w/ater pool 10 feet deep. The dose rates available range from about 2 x lO" 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 buildings 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 WWVB. 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 Mr. Viezbicke or the Engineer in Charge at Ft. Collins, Mr. J. Stanley.

Contact: P. Viezbicke, Chief, Frequency-Time Broadcast Services Section, Radio Building, Room 4030,

NBS Boulder, Colo. 80302. Phone 303-499-1000 ext. 3453.

33
SPECIAL

ANNOUNCEMENTS

ON WWV/VVWVH

Radio stations WWV in Ft. Collins, Colorado, and

WVWH 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. O., Nat. Bur. Stand. (U. S.) Spec.

Publ. 236 (May 1973).

Contact: P. Viezbicke, Chief, Frequency-Time Broadcast Services Section, Radio Building, Room 4030,

NBS Boulder, Colo. 80302. Phone 404-499-1000 ext. 3453.

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 ex34
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. Oscar Menis, Chief, Spectrochemical

Analysis Section, Room B224, Chemistry Building,

phone 301-921-2175.

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 200 to 900 A-—air region, normal inci- dence

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 all 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' (6/xm). 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 Spectro35
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- 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] C. 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, 1000/l( to 10/M (10'' — lO^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 (TGS) pyroeiectric 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, 517 (1968).

[2] P. R. Griffiths, C. T. Foskett, and R. Curbelo,

Appl. Spectrosc. Revs. 6, 31 (1972).

Contact: Dr. Marilyn E. jacox. Act. Chief, Photochemistry 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

36
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 fil 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; Cd 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 Spectrochemical Analysis 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, Spectrochemical Analysis

Section, Chemistry Building, Room B221, 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 apparatus 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. 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 H. Niki, J. Chem. Phys. 57, 3671

and 3677 (1972).

Contact: Dr. Michael J. Kurylo, Photochemistry 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 biological and commercial

polymeric materials.

37
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 <5/iS 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 Polymer

Crystal Physics 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 spectro- meter 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 GC-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 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 at 300 K for bimoiecular and relatively fast termolecular reactions involving ion-neutral collision processes. The kinetics of higher order processes in- cluding 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; simulation of gas phase radiolysis; 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 the operators.

Literature:

[1] J. Am. Chem. Soc. 91, 7627 (1969).

38
[2] J. Chem. Phys. 53, 794 (1970).

[3] J. Am. Chem. Soc. 92, 2937 (1970).

Contact: Dr. Pierre Ausloos, Chief of Radiation Chemistry Section, Chemistry Building, A-265, 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 fim to 1.5 /^m. 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-i. 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 all 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, Chief of isotopic Analysis Section, Physics Building, Room A25, Phone 301-

921-2078.

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

39
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 Sjitm 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 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

TiPe, Nat. Bur. Stand. (U.S.) Tech. News Bull. 54, No. 10, page 239 (1970).

Contact: Dr. L. H. Bennett, Alloy Physics Section,

Materials Building, Room B-150, 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 pho-

! tographic plate, a variable exit slit, or a metal plate

I with eight exit slits.

40
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, Spectrochemical Analysis Section, Chemistry Building,

Room B-218, Phone 301-921-2141.

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. I

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

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

NUCLEAR MAGNETIC

RESONANCE SPECTROSCOPY

41
magnetic mass spectrometer for the detection and

identification of photoions. The best optical resolution 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 Franck- Condon 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, Elementary

Processes Section, Chemistry Building, Room A145,

Phone 301-921-2792.

2550 2500 2150 500 100 300

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-'. 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 K The lasers available are a He-Ne laser operation at 632.8 nm,

60 mW power, and an Ar+ ion laser operating principally at 488.0 or 514.5 nm, powers up to 1 watt. Single frequency operation of the Ar+ laser at 514.5 nm allows use of an lo absorption filter for laser line rejection in the scattered beam. 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.

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 qualified 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 /nm 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 Charcteristics: 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 lO-'^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, Surface 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 secondary

ions. The capabilities of this instrument include trace analysis, isotope ratio measurement, and the detection and

analysis for elements of low atomic number, including

hydrogen. All these measurements can be taken from

a region a few micrometres wide and a few ang- stroms deep.

Operational Characteristics: Specimens of up to 2.54 cm (1 inch) diameter can by analyzed. The specimens

must be flat. Facilities for specimen preparation are

available. All elements can be detected and analyzed

semiquantitatively. The sensitivity is highest for low

atomic number elements, 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.

43
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, of 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, Chief, Surface Chemistry

Section, Chemistry Building, Room B248, Phone 301-

921-2161.

MOLECULAR

BEAM MACHINE

An ultrahigh vacuum, differentially pumped molecular beam machine for high precision work. At pres- ent it uses alkali or alkali halide beams with surface

ionization detection.

Capability: Source is a resistively heated effusion cell. Detector can probe 6.5/im perpendicular to the beam

axis, with a resolution of 0.02/im. Ultimate vacuum is 10-" torr.

Application: Primarily as a research tool for investiga- tion 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, Chief of Surface Chemistry

Section, Chemistry Building, Room B248, Phone 301-

921-2161.

SURFACE IONIZATION ANALYZER.

44
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 Bru- nauer-Emmett-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. Calculations 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 nitro- gen, 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 15 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 determined.

The special sample holders for planar materials enable determination of surface properties and physical

tests on the same specimen.

Availability: To any 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: Mr. W. K. Wilson, Chief, Paper Evaluation

Section, Polymer Building, Room A369, Phone 301-

921-3360.

SURFACE IONIZATION

ANALYZER

Measurements of the surface lifetimes of certain

ionic species, work functions, ionization potentials,

and electron affinities can be made with this instru- ment.

Capability: Adsorption lifetimes of adsorbed ions

(positive or negative) in the region 1 to 500 milli- seconds can be determined. Ionization potential

measurements can be made on those species with

potentials less than about 6 volts; this natural limi- tation arises because metal surfaces on which the

surface ionization occurs do not exceed about 5.5

volts. Work functions may be obtained for those temperature regions in which the surface ionization process is reasonably efficient.

Applications: By making measurements of properties

of a metallic surface which are related to surface

ionization, this analyzer can provide data for ion engines, magneto-hydrodynamic generators, thermionic

converters, and other devices.

Availability: In special circumstances and with prior

arrangement.

Literature:

[1] "The Electron Affinity of Lithium." Milton D. Scheer, and Joseph Fine, J. Chem. Phys. 50, No. 10, 4343-4347, May 15, 1969.

[2] "The Reaction of Carbon Monoxide with a Tantalum Surface Heated above 2000° K." Milton D. Scheer and Joseph Fine, Surface

Science, 12, No. 1, pp. 102-107, Sept. 1968.

[3] "Positive and Negative Self-Surface Ionization of Tungsten and Rhenium." Milton D. Scheer and Joseph Fine, J. Chem. Phys. 46, No. 10, 3698-4003, 15 May 1967.

Contact: Dr. Ralph Klein, Chief, Surface Chemistry

Section, Chemistry Building, Room B248, Phone (301)

921-2161.

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.

415
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. Darrell H. Reneker, Chief, Polymer Crystal Physics Section, Polymer Building, Room A209,

Phone 301-921-3344.

/I

WS / \

UPS^/

-10 -8 -6 -4 -2 0

E-Ep (eV) son X-RAY SPECTROMETER. A comparison of the soft x-ray Mj spectrum (SXS) of Cu witti ultraviolet (UPS) and

x-ray (XPS) ptiotoemission and ion neutralization (INS)

spectra.

SOFT X-RAY

SPECTROMETER

This spectrometer has a 2-meter grazing incidence

and a ruled glass grating, 30,000 lines per inch. It is equipped with a strip 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

V4" 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.

46
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 govern- ment, 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 (Ime)

(NO.,):. 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

47

INDEX

Page

Accelerated Weathering Laboratories 6 Acoustic Anechoic Chamber 4 Acoustic Reverberation Chamber 4

Acoustical Thermometer 23

Alloy Preparation Laboratory 19

Analytical Spectrophotometer 34

Antenna Anechoic Chamber 5 Antenna Field Strength Facilities 5 Automatic Network Analyzer 12

Central Computer Facilities 11 Cobalt-60 Irradiation Facility 33

Concave Crating Spectrographs 35

Cryogenic Flow Research Facility 23

Czerny-Turner Spectrograph 35

Deadweight Force Calibration Machines 25

Electron Energy Loss Spectrometers for Gases . 36

Electron Probe Microanalyzer 43

Electron Van de Graaff Accelerator 2 Electro-optical High Voltage Field Mapping

Systems 13

Far Infrared Spectroscopy 36

Filtered Neutron Beams 29

Fire Research Laboratory 17

Flame Emission Spectrometry with Repetitive

Optical Scanning 36

Flash Photolysis Resonance Fluorescence

Apparatus 37

Fluid Flow Measurement 26

Fluorine Combustion Calorimeter 9

Fourier Transform Nuclear Magnetic Resonance

Spectrometer 37

Gas Chromatograph-Mass Spectrometer System 38

Page

High Pressure Generators 18

High Pressure Optical Fluorescence System . . 18

High Pressure Photoionization Mass

Spectrometer 38

High Pressure PVT Dilatometer 19

High Resolution Infrared Spectrometer 39

High Temperature Controlled-Atmosphere

Furnace 20

High Temperature Vaporization Laboratory ... 20

Hydrogen Liquefaction Facility 24

Inorganic Glasses Laboratory 21 Intermediate-Energy Standard Neutron Field . . 29

Ion Probe Microanalyzer 43

Isotope Ratio Mass Spectrometers 39

Isotope Separator Laboratory 29

Laser Materials Facility 21 Liquefied Natural Gas Flow Facility 24

Linear Electron Accelerator 2 Low Temperature Adiabatic Calorimeter 9 Machine Tools, Numerically Controlled 25

Mercury Manometer 22

Microcaiorimetry 10

Microwave Spectroscopy Facility 39

Millisecond High Temperature Thermophysical

Measurements 22

Molecular Beam-Field Emission Microscope . . 44

Molecular Beam Machine 44

Monoergetic Neutron Beam Facilities 30

Mossbauer Spectroscopy of Metals 40

Multichannel Flame Spectrometer 40

Neutron Diffractometers 30

Neutron Radiography Facility 31 Neutron Scattering Spectrometer 31

National Bureau of Standards laboratories at Boulder, Colorado.

49
INDEX (continued)

Page

Non-Magnetic Facility 13

Nuclear Irradiation Facilities 32

Nuclear Magnetic Resonance Spectroscopy ... 41 Nuclear Orientation Cryostat 24

Nuclear Reactor 28

Photoionization Spectrometry 41 Platinum-lined Adiabatic Solution Calorimeter. 10

Plumbing Research Laboratory 7

Positive-Ion Van de Craaff Accelerator 3 Precision Humidity Measurement 16

Raman Spectroscopy 42

Reactance Bridge for Power Loss Measurement 14

Rooftop Antenna Range 6 Rotating Anode X-Ray Diffraction LJnit 46

Rotating, Platinum-lined, Adiabatic Bomb

Calorimeter 11

Scanning Electron Microscope 15

Soft X-Ray Spectrometer 46

Special Announcements on WWV/WWVH ... 34

Structures Laboratory 7

Sulfur Dioxide Pollution Monitor 16

Surface Area Analyzer 45

Surface Ionization Analyzer 45

Synchroton Ultraviolet Radiation .Facility 3 Thermal Engineering Laboratories 8 Three-Circle X-Ray Diffractometer 47

Three-Dimensional Precision Measurement ... 27

Time-of-FIight Neutron Spectrometers 32

Transmission Electron Microscope 15

Universal Testing Machine, Twelve Million

Pound-Force 27

Wind Tunnel for Unsteady Flows 28

WWVL VLF Broadcast Station 33

National Bureau of Standards laboratories in Montgormery

County, Maryland, near Gaithersburg.

Photo

A. The Administration Building, seen from the courtyard

of the NBS Library.

B. One of the seven General Purpose Laboratories is seen

in the background. 385' x 105', the building contains 348

laboratories and offices. C. The 550 acre NBS-Gaithersburg site seen from the air. The seven General Purpose Laboratories and the 11 -story Administration Building are in the center of the picture. D. Reactor Building. The NBS nuclear reactor and asso- ciated facilities are located in the block-type part of the

structure.

E. This passagew/ay, with its replica in glass of the Periodic Table of the Elements, connects the Isotope Separator

Laboratory with the other wings of the Radiation Physics

Building.

F. Engineering Mechanics Building. The five story highbay space houses the 12 million pound-force Universal

Testing Machine.

50

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