wecA*uc«( ^iote

PB 161552

51

ISOTOPIC ABUNDANCE RATIOS

REPORTED FOR REFERENCE SAMPLES

STOCKED BY THE

NATIONAL BUREAU OF STANDARDS

U. S. DEPARTMENT OF COMMERCE

NATIONAL BUREAU OF STANDARDS
THE NATIONAL BUREAU OF STANDARDS

Functions and Activities

The functions of the National Bureau of Standards are set forth in the Act of Congress, March

3, 1901, as amended by Congress in Public Law 619, 1950. These include the development and

maintenance of the national standards of measurement and the provision of means and methods for making measurements consistent with these standards; the determination of physical constants and

properties of materials; the development of methods and instruments for testing materials, devices,

and structures; advisory services to government agencies on scientific and technical problems; in- vention and development of devices to serve special needs of the Government; and the development

of standard practices, codes, and specifications. The work includes basic and applied research,

development, engineering, instrumentation, testing, evaluation, calibration services, and various

consultation and information services. Research projects are also performed for other government

agencies when the work relates to and supplements the basic program of the Bureau or when the

Bureau's unique competence is required. The scope of activities is suggested by the listing of

divisions and sections on the inside of the back cover.

Publications

The results of the Bureau's work take the form of either actual equipment and devices or published papers. These papers appear either in the Bureau's own series of publications or in the journals

of professional and scientific societies. The Bureau itself publishes three periodicals available from

the Government Printing Office: The Journal of Research, published in four separate sections,

presents complete scientific and technical papers; the Technical News Bulletin presents summary

and preliminary reports on work in progress; and Basic Radio Propagation Predictions provides

data for determining the best frequencies to use for radio communications throughout the world.

There are also five series of nonperiodical publications: Monographs, Applied Mathematics Series,

Handbooks, Miscellaneous Publications, and Technical Notes. Information on the Bureau's publications can be found in NBS Circular 460, Publications of the

National Bureau of Standards ($1.25) and its Supplement ($1.50), available from the Superintendent

of Documents, Government Printing Office, Washington 25, D.C.
NATIONAL BUREAU OF STANDARDS

technical ^lote

51

MAY 1960

ISOTOPIC ABUNDANCE RATIOS

REPORTED FOR REFERENCE SAMPLES

STOCKED BY THE

NATIONAL BUREAU OF STANDARDS

Fred L. Mohler

NBS Technical Notes are designed to supplement the Bureau's regular publications program. They provide a means for making available scientific data that are of transient or limited interest. Technical Notes may be

listed or referred to in the open literature. They are for sale by the Office of Technical Services, U. S. Department of Commerce, Washington 25, D. C.

DISTRIBUTED BY

UNITED STATES DEPARTMENT OF COMMERCE

OFFICE OF TECHNICAL SERVICES

WASHINGTON 25, D. C.

Price 50 cents
National Bureau of Standards

110^ 3 3

cop.l
Isotopic Abundance Ratios Reported for .Reference Samples

Stocked, by the National Bureau of Standards

Fred L. Mohler

Abstract

The National Bureau of Standards maintains a stock

of reference samples of isotopic abundance and this

paper gives results that have been reported on measurements

of these samples. Some information has been received

on 24 of the 32 samples. The paper includes a list of

the reference samples and tables of the results reported

with notes on these results.

1. Introduction

The National Bureau of Standards established a stock

of reference, samples of isotopic abundance in forms

suitable for mass spectrometric analysis in 1955. [l] 1

The objective was to make these samples available to

laboratories engaged in research on natural isotopic

abundance and to serve as a clearing house for data

obtained by these laboratories. In 1957 an unpublished

report was prepared and distributed to interested

scientists which gave a revised list of available samples

and a report on measurements that had been reported to us.

It is the purpose of this paper to bring this information

up to date.

Table 1 lists the present stock of reference samples.

This is the same as the list in the 1957 report except

for the silver sample, No. 1J>. This Was replaced by a

stock of silver nitrate that had been carefully analysed

for another purpose. Gas and liquid samples are distributed

in break seal tubes containing about 3 ml of gas or

about 0.1 g of liquid. Solid samples of about O.lg are

sealed in vacuum in Pyrex tubes.

iNumbers in brackets refer to the Reference list at the

end of the paper.
Table 1

Reference Samples of Isotopic Abundance

No

la

9

9a

10

11

12

13

14

15

20

21

25

26

27

28

29

100

Elements Compound

H,0 H2

H,0

D

Li

LI

K

Rb

Sr

Ag

N

Ca,C,0

C

Mg

Si

B

Si,0

Cu

He

Ne

Ho

SrCO-^

AgNO^

N2

Air

Limestone

Graphite

Mg(0H) 2

SiF4

Borax glass

Silica sand

CuO

Source

Steam Condensate from

Potomac River Water

Snow Water from Yellowstone

D 2 Commercial, 99.8 atom

percent D

Li2C0^ Commercial

Spodumene King's Mountain, N.C.

K2C0^ Commercial

Rb 2C0^ Commercial

Commercial

Working standard used in a

study of isotopic abundance

ratio of Ag

From air

Solenhofen, Bavaria

Spectroscopic grade

Commercial

Commercial

Commercial

Oriskanny deposit, Pa.

Commercial

Atmosphere (Commercial)

Atmosphere (Commercial)
(Table 1 Continued)

No. Elements Compound

102 Ar

105 Kr

104 Xe

105 Gl NaCl

106 Br NaBr

110 Cd Cdl2

120 S Mineral

120a S S0 2

190 Hg Element

200 Pb,S Galena

200a Pb Pbl2

200b Pb Pb(CH

3

)4

Source

Atmosphere (Commercial)

Atmosphere (Commercial)

Atmosphere (Commercial)

Marine, Commercial

Marine, Commercial

Commercial

Wharton Co., Texas

Mineral and Air

Density standard

(limited amount)

Nat. Physical Lab.

Ivigtut, Greenland

From Galena

From Galena
Reported Measurements of Isotope Abundances

About 220 samples have been sent to over 50 different

laboratories in this country and in 14 foreign countries.

Some measurements have been reported on 24 of the J52

samples listed in Table 1. It is to be noted that

scientists interested in the variation of isotope abundance!

in nature have measured differences in abundance in

different samples with a precision approaching one part

in 10 . Values of abundance based solely on ion current

measurements can be uncertain by as much .as one part in

a hundred with a sensitivity limit of about 0.01$ of

the maximum ion peak in conventional mass spectrometers.

Results have been reported in a variety of forms and

show evidence of a wide range of precision and reliability.

We have in general reported measurements in the form given

to us and have not attempted to unify the method of

presenting data. Numerical data are presented in Tables

2 and 3 while other pertinent information is given in the

following notes. Experimental uncertainty indicated is

in general given as the mean deviation except where

specified. However in some instances we lack specific

information on this. Numbers in parentheses are the number

of measurements.

Hydrogen « The four values for D/H ratios have been

corrected for mass spectrometer selectivity by comparison

with standards of known D/H ratio. The differences between

la and 1 have been reported by three laboratories.

Friedman [5] finds sample 1 compared to a Lake Michigan

Sample -.73$. Craig [6] finds the difference -.79$.

Deuterium . The Savanah River Plant Mass Spectrometer

Laboratory measured the deuterium samples by an intercomparison of the spectrum of D2O with one of their standards

The absolute value is based on density measurements

corrected for 1 ' and 18 effects. The National

Bureau of Standards obtained a nearly identical value

from D 2 made by reduction of the D2O but the Savanah

River value is deemed more reliable.

Lithium . The result reported by Cameron [8] is

based on the mass spectrum of lithium iodide. The result

given by Palmer [3] was obtained with a multiple filament

surface ionization mass spectrometer.

Silver . Sample 13 is from a stock of silver nitrate

that has been carefully measured for another purpose.

It has been measured with a multiple filament surface

ionization mass spectrometer and intercompared with

samples of nearly the same isotope ratio made from

weighed amounts of nearly pure Agl07 and Ag109.
Nitrogen. Palmer [3] has reported sensitive measurements

of Nli? abundance in the air sample but with the reservation

that there may be some carbon monoxide' interference.

T. C. Hoering [12] reports that intercomparison of Sample

14 and air nitrogen collected at various times and places

in the United States give n15/n!4 the same within 4 parts

in 10,000. As there is no measurable variation in air

nitrogen, the best values to use for Sample 14 are

carefully measured published values for nitrogen. Junk

and Svec [13] made a careful absolute measurement by

comparison with a synthetic mixture of Nl5 and N1 ^.

Oxygen . Craig [13] has published a detailed intercomparison of oxygen in samples 1 and 20 and in air and

includes values relative to various working standards of

limestone. Absolute values are based on a recomputation

of Nier's measurements of atmospheric oxygen. Palmer [3]

reports measurements on sample 15 and we include in the

table Nier's values for atomic oxygen [l4] which are

widely accepted as a reference standard. There is no

published evidence of appreciable variations in the

isotope ratios of air oxygen and the discrepancy between

Palmer ' s values and Nier ' s values may be experimental

uncertainty in the absolute value.

Carbon . Craig [131 and Ault [15] give comparative

values for the carbon isotope ratios for various limestone

working standards and sample 20 and 21a. Two of these

working standards are as follows:

Nier standard limestone C

1Vc12xl05 1123.00 [13]

" 1124.00 [15]

Univ. of Chicago PDB standard " 1123.72 [13]

1124.7 [15]

Thus Craig [13] found Nier's standard +0.47xlO~5 relative

to sample 20 and Ault finds the difference +O.53 x 10~5.

Gonfiantini [17] found carbon of his Carrara Marble working

standard +3.55xlO~5 relative to sample 20. (The oxygen in

his sample gave 16 18/°21 "> +2.55 x 10"5 relative to sample

20). Holt [52] reported that C1^ abundance is 2.62±.01# less

in sample 21 than in sample 20. Table 2 gives absolute

values based on Craig's value for sample 20.

~5
Silicon . Table 2 gives three measurements of the

isotope abundance of Sample 26, SiF4» David Tilles [18]

has made a comparative measurement of the abundance of

Si^O f sample 28, silica sand, and his working standard

of quartz from the Mother Lode of California. The

relative abundance of Si^O in his working standard is

0.029±.01 percent heavier than sample 28. He measured

Si30/si28+sl 29.

Copper . Both the measurements reported in table 2

were made from the copper iodide mass spectrum. [19] [20]

Helium . Hoffman [21] measured the absolute abundance

of Ke5 in sample 100 by comparison with a synthetic

mixture of He3 and He4. A sample of atmospheric helium

that he prepared gave

HeVHe ^ - i?37 x 10-6

Other Rare Gases » Some values for neon and argon

are given in Table 2 and for convenience in presentation,

krypton and xenon mass spectra are in Table ~$. For

comparison we include data published by Nier [l4, 22] for

the rare gases. His data have been corrected for mass

discrimination by comparison with carefully prepared

synthetic mixtures of A^6 and a40. There is no evidence

of any systematic difference between his corrected values

and the other uncorrected values.

Chlorine . Parker [2j5] has found no significant

differences in chlorine isotope abundances between sample

105 and a wide variety of natural materials. Cl-57/ci3>5

values change by no more than 0.05$ of the ratio. Values

of the ratio for this sample have not been reported to us.

Sulfur . Bradt et al [24] used the S2+ ions of sulfur

vapor to measure the relative abundances of sulfur

isotopes and they also give values based on the SO2

spectrum. Ault [15], Nief [4] and Sakai and Nagasawa [31]

give values of the s34/s;52 ratio using S0 2 made from

sample 120 and Nief and Sakai and Negsawa also measured

the value for sulfur from sample 200 (galena). Nief's

values are relative to Thodes "Utah Pyrite" working

standard taken as S^4/s32 - 4.521$ [25] ; Ault's are

relative to sulfur from Canon Diablo meteorite taken as

4.503$.

Mercury . Sample 190 was measured by four different

laboratories and Dibeler has published the results [26]

in a paper on "isotope Analysis Using Dimethyl Mercury."

The results will not be repeated here as the sample has

not been widely distributed.
Lead . The lead samples have been carefully measured by

a variety of methods. T. J. Chow [27] used a multiple

filament surface ionization source to measure lead from

galena. He reports the mean of J>6 measurements and has

applied a velocity correction to the measured currents.

G. L. Bate [28] measured the spectrum of lead tetramethyl

made from the lead iodide and he reports the mean of 11

sets of measurements. Dibeler [10] measured the lead

tetramethyl of sample 200b and reports the mean of 11

measurements. Harman [29] and Stieff [j>0] have measured

the lead iodide spectrum. Harman has reported the mean

of 12 measurements while Stieff reported the mean of

three sets of analyses two on Pb+ ions and one on

Pbl+ ions.

Conclusions

We are indebted to the many scientists who have

reported the measurements given in this paper. Where

measurements on a sample have been reported by several

laboratories the comparison gives useful information

on the accuracy and reliability of isotope abundance

measurements. The results add materially to the value

of these samples as reference samples.

We wish to thank the U. S. Geological Survey for

supplying samples la, 9a, 20 and 200. They also have given

helpful advice on other samples. V. H. Dibeler procured

the other samples and prepared the samples for distribution,

He also made check measurements of isotope abundance on

many of the samples as noted in the text.
CD OJ OJ K\ oj in vo 00 K\ Ch

COo

•HP

cd «

<uo§ ^

-d o £ OJ 2

~^^ ^

,Q KN

<C •>

OJ• in

O CD OJ OJ •H -d +1 • • ft +i +i O • >fc ^

^s

-P -d VD K\ in O •p rH m OJ

03 CO >R • • • H >R >R >& -=t ^t in ^T

rH rH >& o rHH rH S O O r^\ o 1 i 1 • O O O o O

OJ -P

OO o O

cd • • o • rH = c

<d +' +1 • +1 rH >« rA tn +i o CD .Q \ G\ CD OJ ^f rH

cd P ^t OJ in in ft Eh rHo

rHOrHo

rHo | - = • • • • CO o o

crj o o O

•P

CD>

•H

-P

cd rH

CDh

crj = = C rH rH rH rH rH ^ r

(D

bfl CD CD CD CD CD O rH rH rH rH rH u ft ft ft ft ft

-d

(D i 1 § i = = W co co CO CO CO

cu

in *~»

*~-^ rH

CD ^^» s—>» >

rH rH CD

CD CD rH > >

CD CD CD rH H

CD CD CD O O d

CJ

G •H

CD CD <w d -d £

tH •H

O

Q o

>R o o ^ o o in £ o\ O ^

>R «—

-P

m tcd Ch <J\ KN v * v_^ CT\ r-\ K"\ O O O m rH rH o • o O &0 • o VO • • <C -H

+1 •rH +i +1 \ in

CD J-h" o t-- 0-m

t— \ in ^" o t— • t- • • rH o

CT\ •H OJ CM faO • ON tl rH rH < rH £ rA 3 K\ cr» = rH

«H

g

?H CD P CDu CD

CD rH •H rH CD rH

-P ft ^ ft = > ft 3 £• -P gj rH £2 CO •H CO «H CO Q CO i-q co CO co 8
CD K>

VO IA IA 1^ K\ kn in k\ m OJ

m

rH

o

CVI v '•>

(D d

•

-CJ +3co

^f" ^t O

o

o O

o • • +1

+1 CVI Ch VD

VD vo K\ m

vo

-P

CO

ooH

O

,0002 (20)

2066±, dev. CTv o

CVI

-3- VO

CT\

VO

rH

CVI

GOrHO

vo

rHO

in

io

rH

CVJ rH

in

io

X X

coo

rH

HO

in

io

rHo-=1- vo

• rH

cr> o

o-3-

=*o

o

o• +1GOO

in

in

•

-3" O

m

crv

CVI rH

rHO

in

io

m

in

to

mio

X X

mio

iH

X

I o

CVJ

<uPin

3o

GOrH

o

in

•d • CD cvi to CVJ & rH PQrH

in

o

rHX

rH

cvj rc\ cvi cvj m.

cvj cvj ov ch cr\ rH rH O O O

rH iH H rH iH

CDhCO

u

-p

in

rH

CD rH

p.

GO

O

rH CVJ £ CD (D CM

<D rH rH O

50 ft ft

>5 c £ U

* CD Co •H O CO CO <

in o

rH CVI

CD d CD rH o rH

ft .Q ft g Jh fc £

CO •H Cti CO co < O CO

CVJ

CD rH

ft

CO

9
CD -3- o G\ o

OJ cvj o

r-i OJ o

r-i o

OJ•>

<d

•CJ , , 5 ^_^ • -3- ^—

OJ OJ

d OJ OJ ^s

v ' p v - V - CO

^t- r-i rH in

00 OJ oo o OJ N - <D O -=t o in VD VD m o > z: • o -=1- • • • «H o OJ rH <D +1 • cr\ c^ CT\ go • +1 o• +1 O• +1OJ

r-i

CD

OJ

OJ 3"

00o• •

+1OJ00•

CT\ CTv ONo

r-i rH r-i

C ON oo 00 rH o • • m CD o o

KN

m tr\ -d•H -

rH 00 o• +1 • +1o

OJ £ O t-i tn ON K\

cr\O

O

O o VD in VD

OJ

O OJ OJ o VD • o o o o

•H • O

O 1 r-i -H • • • • GO -Hin

oo VD • +1OJ • +1 in - OH

OJ

m

VD

OJ• (A

OJ

+1in

OJ o o o • • • rH OJ o • • OJ rH ^f -3" ^t in

vo oo• oo• +1 CD

O• +1

-3- o oo• +1

OO• +1 o LO CT\ \ m o & rH in OJ • VD VD E>- 00 OJ iH rH KV OJ m \ -=*- O VD 00 +1 m =t K\ m OJ • • • VO OJ OJ KV m OJ • • OJ m K\ KN

•H OJ OJ OJ 3 • • <D • O o a\

a • • 00 o\ 0\ a\ O OJ OJ W rH <J\ G\ • o o o o

VD

OJ £o CD o r-i •Hi ft i 1 •H §

CO CO

G\

OJ

U CD

CD rH

ft ft

ft £ o CO o COrH

CD

O

CD rH

ft

CO o

CD o =

rH

CD

r-i ft =

CO co

CD a £O

?-.

M

•H Ph < <

OJ = O

G

r-i

O

so

CD

u

r-i cd ft = £ U

CO •H CO <

10
• -=t ^f

<M CM OJ

CD «

in vo

m ^t- rH

m

r>- GO o Q\ o

CVi OJ r-i OJ

vo

OJ

m CT\

m o o o r-i o • • • • • +1 CO +1 +1 •H +i m o VO iH m ON o\

OJ

m

mH OJ OJ • • • • • K\ K\ m K\ K\

in in in

m in

-3- rH 1 rH vo O CD tn • O >

CD

r-i r-i O

OJo

rH

OJ o

OJo• rH C- CD • • • • -H O o O [>- M +1 +1 +1 VO • • £ o OJ vo CO GO m

+1 +1 CD OJ VO in vo vo vo

-=f OJ K\ Xi • • • • • K\ OJ OJ •H OJ OJ OJ OJ OJ • • «m OJ OJ OJ OJ OJ ^f ^T OO

-3- -^f o rH >& rH ^i- r- KA o o O in O o rH o • K\ • • G\ • • • • +1 m +1 -H vo +1 +1 -H +1 o o OJ o CO o m o\ m

VO t>- >R >R ^. >R >& OJ -=t vo vo -3- in

t- t- K\ CO G\ t>- Ch • • O O O r-i o OJ OJ OJ OJ OJ o O

OJ

O• +1O• -HO• +1

-=t

O• +1 vo o• +1m

OJ OJ OJ OJ OJ o o \ O 00 G\ o G\ • • -3" in -=t -=t in ^t

OJ in in

m • • • • • CM r^v

m o\

CO

co ^i- ^1-

CO O

OJrH

•v

^i- ^r

^1- o

OJ

OO• +1o-3- m

r-i

vooo• +1m

in

rH

CO

OJo• -Hin

r-i

r-i o• -Hin

r-i

co oo• +io\m

in

rH

CO o o o O o o o o o o o o

OJ OJ OJ OJ OJ o o o o o o o

rH rH r-i rH rH OJ OJ OJ OJ OJ OJ OJ

u <u <D CD CD CD CD CD CD 3 r-i rH r-i rH rA rH rH rH

<H Pi P. P. T5 Pi Pi Pi Pi p. rH {q £ E cd £ Jq £ g Jq 3 CO CO CO CO CO CO CO CO co CO CO co 1-3 CO CO CO CO co

11
Table 3

Krypton and Xenon Iso tope Abundances

m/e Krypton; Sample 103 and Univ. of Minn. Sample

Ref. 4* Ref. 10** Ref. 11*** Ref. 22

78 0.351±.001 0.354±.001 .355 0.354±.002

80 2.256±.005 2.28±.03 2.28 2.27±01

82 11.52±.02 11.662±.03 11.6 11.56±.02

83 11.49±.015 11.578±.04 11.56 11.55±.02

84 56.99±.06 56.77±.04 56.92 56.90±.l

86 17.4l±.03 17.35±.02 17.25 17.37±.02

Xenon, Sample 104 and Univ. of Minn. Sample

m/e Ref. 4* Ref. 10** Ref. 11*** Ref. 22

124 0.094±.001 0.094±.001 (.10) - 0.096±.001

126 0.088±.001 0.090±.001 (.10) 0.090±.001

128 1.921±.007 1.923±.006 1.935 1.919±.004

129 26.25±.05 26.33±.04 26.39 26.44±.08

130 4.10±.01 4.135±.01 4.155 4.08±.01

131 21.l6±.05 21.19±.03 21.15 21.18±.05

132 26.91±.04 26.93±.02 26.89 26.89±.07

134 10.49±.03 10.4l±.02 10.48 10.44±.02

136 8.94±.02 8.87±.03 8.8358 . 87± . 01

*Standard deviation in over 20 measurements.

**Mean of 24 measurements of krypton and 11 of xenon.

***2 measurements.

12
References

1. F. L. Mohler, Science 122, 334 (1955).

2. Y. Horibe and M. Kobayakawa, Bull. Chem. Soc.

Japan j£3, 116 (1959).

3. G. H. Palmer, U. K. Atomic Energy Authority, Harwell,

England.

4. G. Nief, Comm. A. L.'Energie Atomique, Saclay.

5. Irving Friedman and R. L. Smith, Geochim. et

Cosmochim. Acta 15, 218 (1958).

6. Harmon Craig at Univ. of Chicago.

7. Savanah River Plant, Mass Spectrometric Laboratory.

8. A. E. Cameron, Oak Ridge National Laboratory.

9. W. R. Shields, D. N. Craig and V. H. Dibeler, (in Press).

10. V. H. Dibeler, National Bureau of Standards.

11. H. C. Mattraw, Knolls' Atomic Power Laboratory.

12. T. C. Hoering, Geochim. et Cosmochim. Acta 13,

225 (1958).

13. Harmon Craig, Geochim. et Cosmochim. Acta 12, 133 (1957).

14. A. 0. Nier, Phys. Rev. 77, 789 (1950).

15. W. U. Ault, Geochim. et Cosmochim. Acta 16, 201 (1959).

16. Gregor Junk and H. J. Svec, Geochim. et Cosmochim.

Acta 14, 234, 1958.

17. H. Gonfiantini, Lab. for Nuclear Geology, Pisa, Italy,

1958.

18. David Tilles, Univ. of California.

19. Walker, Cuttitta and Senftle, Geochim. et Cosmochim.

Acta 15, 183 (1958).

13
20. W. A. Pfeiler, Y-12 Laboratory, Oak Ridge, Term.

21. John Hoffman, Univ. of Minnesota.

22. A. 0. Nier, Phys . Rev. 79, 450 (1950).

25. Patrik L. Parker, Univ. of Arkansas.

24. Bradt, Mohler and Dibeler, J. Res. NBS 57, 223 (1955).

25. Thode, Macnamara and Collins, Can. J. Res. B27, 36l

(1949).

26. V. H. Dibeler, Anal. Chem. 27, 1958 (1955).

27. T. J. Chow, Calif. Institute of Technology.

28. George L. Bate, Lamont Geological Observatory.

29. W. D. Harman, U.C.N.C. Oak Ridge, Term.

30. Lorin R. Stieff, U.S. Geological Survey.

31. H. Sakai and H. Nagasawa Geo. Chim. et Cosmochim.

Acta 15, 32, (1958).

32. Ben D. Holt, Argonne National Laboratory.

1J* USCOMM—DC-
U.S. DEPARTMENT OE COMMERCE

Frederick H. Mueller, Secretary NATIONAL BUREAU OF STANDARDS

A. V. Astin, Director THE NATIONAL BUREAU OF STANDARDS

The scope of activities of the National Bureau of Standards at its major laboratories in Washington, D.C., and

Boulder, Colorado, is suggested in the following listing of the divisions and sections engaged in technical work.

In general, each section carries out specialized research, development, and engineering in the field indicated by

its title. A brief description of the activities, and of the resultant publications, appears on the inside of the front

cover. WASHINGTON, D.C.

Electricity and Electronics. Resistance and Reactance. Electron Devices. Electrical Instruments. Magnetic Measurements. Dielectrics. Engineering Electronics. Electronic Instrumentation. Electrochemistry.

Optics and Metrology. Photometry and Colorimetry. Photographic Technology. Length. Engineering

Metrology.

Heat. Temperature Physics. Thermodynamics. Cryogenic Physics. Rheology. Molecular Kinetics. Free Radicals Research. Atomic and Radiation Physics. Spectroscopy. Radiometry. Mass Spectrometry. Solid State Physics. Electron Physics. Atomic Physics. Neutron Physics. Radiation Theory. Radioactivity. X-rays. High

Energy Radiation. Nucleonic Instrumentation. Radiological Equipment.

Chemistry. Organic Coatings. Surface Chemistry. Organic Chemistry. Analytical Chemistry. Inorganic

Chemistry. Electrodeposition. Molecular Structure and Properties of Gases. Physical Chemistry. Thermochemistry. Spectrochemistry. Pure Substances.

Mechanics. Sound. Mechanical Instruments. Fluid Mechanics. Engineering Mechanics. Mass and Scale. Capacity, Density, and Fluid Meters. Combustion Controls.

Organic and Fibrous Materials. Rubber. Textiles. Paper. Leather. Testing and Specifications. Poly- mer Structure. Plastics. Dental Research.

Metallurgy. Thermal Metallurgy. Chemical Metallurgy. Mechanical Metallurgy. Corrosion. Metal

Physics.

Mineral Products. Engineering Ceramics. Glass. Refractories. Enameled Metals. Constitution and Microetructure.

Building Technology. Structural Engineering. Fire Protection. Air Conditioning, Heating, and Refrigeration. Floor, Roof, and Wall Coverings. Codes and Safely Standards. Heat Transfer. Concreting Materials.

Applied Mathematics. Numerical Analysis. Computation. Statistical Engineering. Mathematical Physics.

Data Processing Systems. SEAC Engineering Group. Components and Techniques. Digital Circuitry.

Digital Systems. Analog Systems. Application Engineering.

• Office of Basic Instrumentation. • Office of Weights and Measures. BOULDER, COLORADO

Cryogenic Engineering. Cryogenic Equipment. Cryogenic Processes. Properties of Materials. Gas Liquefaction. Radio Propagation Physics. Upper Atmosphere Research. Ionospheric Research. Regular Propagation

Services. Sim-Earth Relationships. VHF Research. Radio Warning Services. Airglow and Aurora. Radio

Astronomy and Arctic Propagation.

Radio Propagation Engineering. Data Reduction Instrumentation. Modulation Research. Radio Noise. Tropo8pheric Measurements. Tropospheric Analysis. Propagation Obstacles Engineering. Radio-Meteorology. Lower Atmosphere Physics.

Radio Standards. High Frequency Electrical Standards. Radio Broadcast Service. High Frequency Impedance Standards. Electronic Calibration Center. Microwave Physics. Microwave Circuit Standards. Radio Communication and Systems. Low Frequency and Very Low Frequency Research. High Fre- quency and Very High Frequency Research. Ultra High Frequency and Super High Frequency Research. Modula - tion Research. Antenna Research-. Navigation Systems. Systems Analysis. Field Operations.
B£