National Bureau of Standards

Library, N.W. Bldg

DEC 7 1965 NBS MISC. PUBL. 260-9

o

a

Standard Reference Materials:

HALF LIVES OF MATERIALS USED IN THE PREPARATION OF

STANDARD REFERENCE MATERIALS OF NINETEEN RADIOACTIVE NUCLIDES

ISSUED BY THE NATIONAL BUREAU OF STANDARDS

U.S. Department of Commerce

:<LjJ National Bureau of Standards
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UNITED STATES DEPARTMENT OF COMMERCE • John T. Connor, Secretary NATIONAL BUREAU OF STANDARDS • A. V. Astin, Director

Standard Reference Materials:

Half Lives of Materials Used in the Preparation

of Standard Reference Materials of Nineteen Radioactive Nuclides

Issued by the National Bureau of Standards

S. C. Anspach, L. M. Cavallo, S. B. Garfinkel,

J. M. R. Hutchinson, and C. N. Smith

Institute for Basic Standards

National Bureau of Standards Washington, D.C.

National Bureau of Standards Miscellaneous Publication 260-9

Issued November 15, 1965

For sale by the Superintendent of Documents, U.S. Government Printing Office Washington, D.C, 20402 - Price 15 cents
PREFACE

Within the frame work of the National Bureau of Standards Institutes

the area of standard reference materials is a broad and important one, including- the preparation, characterization and distribution of a wide

variety of materials in such diverse fields as metallurgy, polymers and inorganic materials. In carrying out such a program there is much inter- action with representatives of industry and science, beginning with dis- cussions as to which primary standard materials will do most to advance

technology, the furnishing of materials and fabrication of samples, and

the characterization and certification of the materials by cooperative

efforts. The many groups participating in a standards program are very interested in detailed information on specific aspects of the program —

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discussions.

To meet this need, NBS Miscellaneous Publication 260 has been reserved for a series of papers in the general area of "standard reference

materials". This subject-oriented series will provide a means for rapid

dissemination of this detailed information and we hope will stimulate the use of standard reference materials in science and industry.

W. Wayne Meinke, Chief

Office of Standard Reference Materials

Library of Congress Catalog Card Number: 65-62744

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STANDARD REFERENCE MATERIALS: HALF LIVES OF MATERIALS USED IN THE PREPARATION

OF STANDARD REFERENCE MATERIALS OF NINETEEN RADIOACTIVE NUCLIDES

ISSUED BY THE NATIONAL BUREAU OF STANDARDS

S. C. Anspach, L. M. Cavallo, S. B. Garfinkel.

J. M. R. Hutchinson, and C. N. Smith

Institute for Basic Standards National Bureau of Standards ABSTRACT

Values are given for the half lives of materials used in the

j , c XT 22 „ 45 _ 46 „ 54 _ 57 „ 60 preparation of standard samples of Na , Ca , Sc , Mn , Co , Co , _ 65 _ 85 _ 85 _ 89 _ 90 88 „ 95 125 „ 139 _ 141 147 Zn , Kr , Sr , Sr , Sr , Y , Nb , I , Ce , Ce , Pm , Hg^^, Tl^^, issued by the National Bureau of Standards. Instrumentation, source preparation, and the determination of impurities are

also discussed.

Key Words: Half lives, calcium-45, cerium-139, cerium-141, cobalt57, cobalt-60, iodine-125, krypton-85, manganese-54, mercury-203,

niobium-95, promethium-147, scandium-46, sodium-22, strontium- 8 5, strontium-89, strontium-90, thai Hum- 204, yttrium-88 and zinc-65.

1
For many years, members of the Radioactivity Section of the National Bureau of Standards have followed the half lives of sources prepared from the same materials used in the preparation of standard

samples of radionuclides for distribution. The results of this program

have not previously been published, and in view of the widespread

distribution of these standards, and the large spread in the reported

values of the half lives of many of the radionuclides involved, these

results are being presented so that appropriate decay corrections may be applied by users of these standards.

In most cases the purified radioactive material was obtained

from commercial sources or Oak Ridge National Laboratory. In some

cases, further purification was made in this laboratory, or the material was examined spectrometrically for impurities. When information on

the radioactive purity is available, it is given. However, the extent to which the logarithmic plot of the measured activity, over

an extended period of time, approximates a straight line is taken as an indication of the radioactive purity. The instruments used in these determinations were the National Bureau of Standards hjcy ionization chamber, the National Bureau of Standards 2jtP ionization chamber, and the National Bureau of Standards

kxfi flow proportional counter, all described in NBS Circular No. 59^. The determinations consist of individual observations made at conven- ient time intervals. The half lives and their standard errors were calculated from the straight line fitted to the data by the method of least squares. In some determinations, measurements were made on several

2
sources from the same material. The value of the half life and the standard error associated with it were computed for each source

separately. Each value was then weighted with its error and the weighted average reported. The error reported was computed using

the formula:

With the exception of krypton-85., sources for the 4jry ionization

chamber were 5 milliliters of radioactive solution, flame-sealed in glass ampoules. The krypton-85 source was approximately 30 of gas in a break-seal glass ampoule. Each source was compared with a radium-226 reference source, the ratio of the activity of the source under investigation to that of the radium-226 source constituting one observation. Corrections (if significant) were made for the decay of radium-226, using a half-life value of 1622 years. The temperature

and pressure were carefully monitored during each measurement and

appropriate corrections made for changes in air density. Sources for the 2jtP ionization chamber were made by imbedding

the radioactive material in epoxy resins mounted in aluminum holders. These were compared with either a radium-226 or a cesium-137 reference

137

source. A half life of 29.5 years was assumed for the Cs reference

source

.

3
Sources for the hnfi proportional counter were prepared by- depositing aliquots of radioactive solutions on thin plastic films

2 2 (~ 4pg/cm to 25 ug/cm thick) which had either electrically conducting

coatings of gold (~ 20 (jg/ cm ) evaporated on them, or aluminum leaf backings (~ 220 ug/ cm ). The aliquots of solution were dried and

then covered with films identical to the supporting ones to produce

a symmetrical sandwich. The sources were counted in the hufi propor- tional counter, the counts per second at a given time constituting

one observation. The hit geometry and the stability of the instrument made measurement of a reference source unnecessary. The dead time

of the counting system was checked periodically and small corrections were made.

he The material used in the determination of the half lives of Sc , Mn

5i|

', Co 57

, Sr85, Y

88

, Ce159

, Hg

2°5

, and the Zn

65 issued after 1959, were examined in this laboratory for gamma-ray impurities with a Nal(Tl) scintillation spectrometer at the time of the initial measurement. Approximately 10^ counts in the full-energy peak (or peaks)

characteristic of the radionuclide under investigation were collected.

No other peaks greater than 0.1$ of this value, were observed.

In the case of the Mn^ (^997 series), an iron-55 contaminant was removed chemically prior to the standardization. It was estimated

that there was less than 0.1$ iron-55 remaining.

Oq The Sr material was examined with both a Nal(Tl) scintillation

spectrometer and a beta-ray anthracene scintillation spectrometer

at the time of the initial and final half -life measurements. The Sr
disintegration rate was found to be 0.096$ of the Sr initially,

with about 30$ of this being detected in the 4jtf3 counter as compared

Qq qq qq with 99$ of the Sr . The Sry -Y disintegration rate was found to be less than 0.02$ of the Sr

8

^ initially, the Sr^°-Y^° having the

89 same efficiency as the Sr . The contribution of these contaminants was considered to be insignificant and no corrections were made for

them. 125 A cesium-137-bari urn- 137m impurity in the I (htyhh series) was detected spectrometrically and found to have a disintegration rate 125 approximately 0.015$ that of the I on the date of issue. The

source used for the half -life measurement was, therefore, remeasured

428 days after the final half -life measurement. The activity due to iodine-125 still present was calculated, using a 60-day half life,

and subtracted from the measured activity. The remaining activity was assumed to be due to the cesium-137-t>arium-137in impurity and was subtracted from the half-life data used to determine the value given

in Table 1 for iodine-125.

Similarly, the contribution of a cerium-l44-praseodymium-l44

contaminant, which was observed spectrometrically in the Ce^~^(h^k6

series), was determined from a measurement of the half -life source 260

days after the final half-life observation, and was subtracted from

the data used to determine the value shown in Table 1 for cerium-l4l.

The disintegration rate of the cerium-l44-praseodymium-l44 contaminant

was computed to be approximately 0.64$ of that from the Ce"^"

1" on the date of issue of the 49^6 series.

5
A list of references to some of the more recently published values

for the half lives of the radionuclides appearing in Table 1, is given

here.

Table 1 Nuclide Half Standard No. of Number Standard Date Instru- No. of Life Error Obser- of Half Sample Issued ment Sources vations Lives Number Used* per Measured Batch

tvt c-1- Na 2.59iy 0.003y 56 2.6 ^921 10-14-54 4*7 2 2.6l3y O.Olly 13 • 5 4922 -B 4-29-59 1 2.603y O.OOly 29 1.2 |4921-B

^922-C

12-11-61

12-11-61

11 1

Ca4;? 2.602y O.Olly 11 • 5 4922 -D 6-30-64 11 1 lo2.63d O.lld 46 5.8 k9h2 2-1-62 4jrp 4 46

Sc

° 83.80d 0.03d 2k 2.8 4939 7-20-60 4*7 1

S4 311. 9d 0.2d 26 1,3 4997 9-1-60 kjcy 1

^1 1 Qrl 0 0 2d "In _LU /4997-B 4997-C 7-24-61

3-1-62

H 1

312. 6d 0.4d Ik 1.6 4997 -D 10-22-63 11 1

Co 57 271.65a 0.13d 27 2.1 4941 12-19-61 4jty 1

Co 5.2i+2y 0.008y 34 1 {49l4j

|4915

49l4-A\

14915 -A 10-1-53

4*7 1

Zn

6^ 2^3»ld 0.7d 44 3.1 4930 3-1-57 4jt7 3 244 . 12d 0.12d 50 2.1 4930-B 3-H-60 11 2 242.78d 0.19a 18 2.1 ^4930-c 8-2-61 ti 1

Kr85 V930-D 1-7-62 11 10.757 o.03y 24 •59 (^935

! |

i+935-A 12-10-57 4^7 1

Sr

85 65.19d. 0.13d 6 1.4 4938 8-24-59 4jt7 1 Y

88

106. 52d 0.03d 19 2.6 4998 9-10-61 4*7 1

106. 67d 0.03d 18 2-7 4998-C 3-12-65 1

6
Table 1 Continued

Nuclide Half Standard No. of Number Standard Date Instru- No. of Life Error Obser- of Half Sample Issued ment Sources

vations Lives Number Used per Measured Batch

Sr

Sr90

.125

Pm

139 141

1V7

Hg203

Tl20k

50.70d 0.19d 8 1.8 I 1+9^5 12-5-63 2«P 1 50.52d 0.03d 62 5-1 4945 7B i 9-1-64 4nP 4 28.82y 0.1% 69 • 39 | 4919 ,4-15-53 4*p 6 4919 -B 14-6-57

2JtP11 59.83d O.lld 20 3.3 4944 12-19-62 1

137. 5d 0.3d 9 1.2 4999 1-1-63 4jT7 1

32.55cL 0.007d 30 5.2 4946 1-3-64 4*7 1 2.6l8y 0.0077 33 1.3 f 4940 5-1-61 4*p 2

46.56d 0.02d 9 4.

4932 3-12-59 4*7 1

46.577<l 0.008d 18 5-1 i+932-C 5-28-64 4*7 1 3.75% 0.004y 53 1.9 4920-B 6-7-57 4*p 2

* 4*7 - 4*7 ionization chamber

4*p - 4*p proportional counter

2jtP - 2jtP ionization chamber

^The Sr ^ source was compared with a Cs"^^ reference

source as a Ra^^ reference of comparable intensity

was not available.

"^The source was compared with a Ra^^ reference

7
Na (2.6 ± ? )y (2.58±0.03)y

(2.62±0.02 )y

Ca

45 (l6U±4)d

(166 ± ? )d

(l53±2)d

(l67±3)d

(l65.1±0.7)d

Sck6 (82.9±1.6)d

(84.1±0.3)d

(83.8910. 12 )d (84.2±0.2)d

References *

L. J. Laslett, Phys. Rev. 76, 858 (19^9)

¥. F. Merritt, P. J. Campion, R. C. Hawkings,

Can. J. Phys. 35, 16 (1957)

E. I. Wyatt, S. A. Reynolds, T. H. Handley,

W. S. Lyon, H. A. Parker, Nuclear Sci. and

Eng. 11, 7^ (1961) C.F.G. Delaney, J.H.J. Poole, Phys. Rev. 89, 529 (1953)

V. I. Breslav, Trudy Inst. Fiz., Akad. Nauk. Latv. SSR Ser. Fiz. i Tekh. Primenen. Radioaktiv.

Izotopov 9, 33 (1956)

Chem. Abstr. 51, No. 17^901 (1957)

H. Thiry, Bull. soc. roy. sci. Liege 26, 29 (1957)

J. P. Cali, L. F. Love, Nucleonics 17, No. 10, 86 (1959)

E. I. Wyatt, et al, Nuclear Sci. and Eng. 11, 74 (1961)

G. Rudstam, Thesis, Univ. of Uppsala (1956)

R. P. Schuman, M. E. Jones, A. C. Mewherter,

J. Inorg. Nuclear Chem. 3, 160 (1956)

K. ¥. Geiger, Phys. Rev. 105, 1539 (1957)

H. W. Wright, E. I. Wyatt, S. A. Reynolds, W. S. Lyon, T. H. Handley, Nuclear Sci. and Eng. 2, 427 (1957)

8
(291±l)d E. W. Backofen, R. H. Herber, Phys. Rev. 97, 7^3 (1955)

(278±5 )d R. P. Schuman, M. E. Jones, A. C. Mewherter,

J. Inorg. Nuclear Chem. 3, 160 (1956)

( 29016 )d P. Kafalas, J. W. Irvine, Jr., Phys. Rev. 10k, 703 (1956)

(313. 510.7 )d E. I. Wyatt, et al, Nuclear Sci. and Eng. 11, lh (1961)

(270 ± ? )d J. J. Livingood, G. T. Seaborg, Phys. Rev. 60, 913 (19^1)

(267 ± ? )d J. M. Cork, M. K. Brice, L. C. Schmid, Phys.

Rev. 99, 703 (1955)

(5.24±0.03)y K. W. Geiger, Phys. Rev. 105, 1539 (1957)

(5.3310.04)y J. P. Keene, L. A. Mackenzie, C. W. Gilbert,

Phys. in Med. Biol. 2, 360 (1958)

(5. 26310. 003 )y S. G. Gorbics, W. E. Kunz, A. E. Nash,

Nucleonics 21, No. 1, 63 (1962)

(2U5.0+0.8)d J. Tobailem, J. phys. radium ik, 553

(2l+3.5i0. 8 )d K. W. Geiger, Phys. Rev. 105, 1539 (1957)

(2i+6.4l2.2)d H. W. Wright, E. I. Wyatt, S. A. Reynolds,

W. S. Lyon, T.,H. Handley, Nuclear Sci. and

Eng. 2, U27 (1957)

(I0.57±0.l4)y J. F. Turner, AERE N/R 125^ (1953)

(10. 27+0. 18 )y R. K. Wanless, H. G. Thode, Can. J. Phys. 31, 517 (1953)
Kr85 (I0.76±0.02)y J. Lerner, U.S.A.E.C. TID-I6627 (1962)

(Continued)

Sr

85 (65±3)d M. Ter-Pogossian, F. T. Porter, Phys. Rev. 8l, 1057 (1951)

(65.0±0. 7 )d G. Herrmann, F. Strassmann, Z. Naturforsch 11a, 9h6 (1956)

(64.010. 2 )d H. ¥. Wright, E. I. Wyatt, S. A. Reynolds,

W. S. Lyon, T. H. Handley, Nuclear Sci. and

Eng. 2, U27 (1957)

00 Y (105 ± 5)d L. A. DuBridge, J. Marshall, Phys. Rev. 58, 7 (19^0)

(I04±2)d R. T. Overman, AECD-354 (19^6)

(I05±l)d 0. U. Anders, Thesis, Univ. of Mich. (1957)

(108. 1+0. 3 )d E. I. Watt, et al, Nuclear Sci. and Eng. 11, lh (1961)

Sr

8^ (50. 36±0. 18 )d R. G. Osmond, M. J. Owers, J. Inorg. Nuclear

Chem. 9, 96 (1959)

(53.6±0.4)d A. R. Sattler, Nuclear Phys. 36, 648 (1962) Sr^° (29.3±1. 6 )y M. P. Anikina, R. N. Ivanov, G. M. Kukavadze,

B. V. Ershler, Atomnaya Energ. k, 198 (1958);

J. Nuclear Energy 9, 167 (1959)

Nb^ (35±l)d D. W. Engelkemeir, E. L. Brady, E. P. Steinberg, NNES 9, 722 (1950)

(35.0±0.5)d J. M. Cork, J. M. LeBlanc, D. W. Martin, W. H. Nester, M. K. Brice, Phys. Rev. 90, 579 U953)

(35.0±0.l)d E. I. Watt, et al, Nuclear Sci. and Eng. 11, 7 4 (1961) 10
I (60.0±0.5)d G. Friedlander, W. C. Orr, Phys. Rev. 84, 484 (1951)

(58.8±0.2)d G. I. Gleason, Abbott Lab., Oak Ridge, Term., private communication, 5-20-63

Ce159 (l40+l)d M. L. Pool, N. L. Krisberg, Phys. Rev. 73, 1035 (1948)

Ce

1^1 (33.110.2 )d D. Walker, Proc. Phys. Soc. (London) A62, 799

(19^9)

(32.5±0. 2 )d M. S. Freedman, D. W. Engelkemeir, Phys. Rev.

79, 897 (1950)

(32. 51+0. 02 )d B. H. Kettelle, A. R. Brosi, Nuclear Data Sheets

October, 1957 Pm

1^ (2.66±0.02)y R. P. Schuman, M. E. Jones, A. C. Mewherter,

J. Inorg. Nuclear Chem. 3, 160 (1956)

(2. 64+0. 02 )y W. F. Merritt, P. J. Campion, R. C. Hawkings,

Can. J. Phys. 35, 16 (1957)

(2.7±0.l)y J. P. Call, L. F. Lowe, Nucleonics 17, No. 10, 86 (1959)

(2.5010. 03 )y E. I. Watt, et al, Nuclear Sci. and Eng. 11, 74

(1961)

(2.6710. 06)y F. P. Roberts, E. J. Wheelwright, W. Y. Matsumoto, H. W. -77296 (1963)

Hg

2°5 (47.910.2 )d J. M. Cork, D. W. Martin, J. M. LeBlanc,

C. E. Branyan, Phys. Rev. 85, 386 (1952)

11
(46.91±0.l4)d G. G. Eichholz, J. V. Krzyzewski, Can. J. Phys. 54, 1167 (1956)

(47.1+0.2 )d H. Thiry, Bull. Soc. Roy. Sci. Liege 26, 29

(1957)

(47.210.7 )d J. P. Call, L. F. Lowe, Nucleonics 17, No. 10, 86 (1959) Tl

20k (3-56±0.05)y W. F. Merritt, P. J. Campion, R. C. Hawkings,

Can. J. Phys. 35, 16 (1957)

(4.11±0. 13 )y J. E. Edwards, J. Inorg. Nuclear Chem. 7, 336

(1958)

(3. 5710. 04 )y E. I. Wyatt, et al, Nuclear Sci. and Eng. 11, 74 (1961)

(3. 80+0. 02 )y G. Harbottle, Nuclear Physics 4l, 604 (1963)

*For interpretations of the errors shown, refer to original publications.

12

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