J.RADIOANAL.NUCL.CHEM.,LETTERS 137 /5/ 381-388 /1989/

IMPROVED VALUES OF HALF-LIVES OF SEVERAL NUCLIDES

A. Abzouzi x, M.S. Antony, V.B. Ndocko Ndongu6 xx

Centre de Recherches Nucl6aires, IN2P3-CNRS/Universit6 Louis Pasteur,

BP 20, F-67037 Strasbourg Cedex, France

XXInstitut Universitaire de Technologie, Universit6 de Haute Alsace,

68093 Mulhouse Cedex, France

Received 4 August 1989 Accepted 1 September 1989

- 66 81m_ l16m~ 140La The half-lives of Cu. se. • 143Ce , 171Er , 177Yb, 186Re, 188mRe and 188Re' have been determined more accurately compared to previous measurements.

INTRODUCTION

The present work is a part of a continuing program to

reevaluate the half-lives of nuclides accessible at the

on-campus research reactor of the Centre de Recherches

Nucl~aires of Strasbourg, and their eventual citation in

the forthcoming project "Nuclides Chart-Strasbourg 1990".

Xpermanent address: Institut de Physique, Universit~ des Sciences et de la Technologie Houari Boumedienne, Alger, Algeria.

4 381 Elsevier Sequoia S. A., Lcatsanne Akaddmiai Kiadd, Budapest

ABZOUZI et al.: IMPROVED VALUES OF HALF-LIVES

TABLE 1

Details of samples and experimental procedures

Sample Isotopic Weight of Irradiation Counting abundance, sample, time, time

% mg min

65CUO 30.8 50 1 3 min

8Ose 49.6 50 5 19 min

ll5In 95.7 50 0.75 31 min

139La 99.9 50 5 21.5 h

142Ce Ii.i 50 60 2 h

17OEr O 14 9 50 5 1 h 176 2 3

Yb203 12.7 50 0.5 15 min

185Re 37.4 5 15 2 h

187Re 62.6 5 5 8 min M

187Re 62.6 5 5 2 h

XFor the isomeric state in !88Re.

EXPERIMENTAL

The radionuclides were obtained from /nth,Y/ reactions.

The samples were irradiated at the core of the reactor

where the thermal neutron flux was l.lxlO 12 n.cm -2 -i �9 sec ,

except in the case of ll51n for which the flux was

I0 IO n.cm -2.sec -I. Half-lives were extracted from the

decay curves of the most intense y-ray via 8 decay.

Single y-ray spectra were recorded with a iO4,cm 3 coaxial

Ge/Li/ detector for all nuclides while for 66Cu a lO-cm

diameter NaI/TI/ detector was employed�9 The resolution of

the Ge/Li/ detector was 3.2 keV for the 1333 keV peak of

6Oco"

Details of samples and experimental procedures are

given in Table i.

382

ABZOUZI et al.: IMPROVED VALUES OF HALF-LIVES

O u

E z

106 ~ l m s e ,8- ,81Br

if , , h I ~ , , , I ,~,

I0 S

0 76 152 228

Time, min

Fig. i. Decay curve of 81mse

RESULTS

Figures 1-4 show the evolution of the areas of the y-

ray peaks as a function of time. Results of half-lives

extracted by least squares fitting to the natural loga-

rithm of the areas of y-ray peaks/time interval between

two successive counting times are indicated in Table 2

and are compared with published values, most of them ob-

tained from Nuclear Data Sheets. Numbers in parenthesis

represent uncertainties in the last significant digits:

33.O39/6/h means 33.039+0.006 h.

4* 383

ABZOUZI et al.: IMPROVED VALUES OF HALE-LIVES

10 s _

10 z' .

106 C

O u

"6

.D

E D

z

F~- ..116 S n

1294 keY

0 124 248 372 496 Time, min

Fig. 2. Decay curve of ll6mIn

CONCLUSION

Substantial improvements in the half-life values of

i0 nuclides have been made in the present investigation.

The results for iO other nuclides under analysis will be

submitted for publication in the near future.

The collaboration of D. Oster of the Radioprotection

Department is gratefully acknowledged.

384

ABZOUZI et al.: IMPROVED VALUES OF HALF-LIVES

La 13-1 l'~

1597 keV

ta 10 e

"5

2

10 s " ' ~

i ] 1 1 i ~ t 1 i l

0 86 172

Time., h

Fig. 3. Decay curve of 14OLa

D O

E Z

~ 1 ~ 186D ~ I~-"' 186~ lo 6- . ~ ,,~ ~ u s

10 s

, J J L I k I = i = [ k a = 1 , i i ~ % -

0 8~ 176 264 352 44( Time, h

Fig. 4. Decay curve of 186Re

385

ABZOUZI et al.: IMPROVED VALUES OF HALF-LIVES

TABLE 2

Half-lives of nuclides in this work compared with previous values

Nuclide Ey ana- No. of Half-life Half-life lyzed, runs /this work/ /previous keY values/

Re f.

66Cu 1039 3 5.10 /2/ min 5.07 /2[ min 1 5.1 /i/ min 2 5.13 /3/ min 3

81mse 103 4 57.28 /2/ min 57.28/5/ min 4

ll6mIn 1294 2 54.11 /3/ min 54.05/16/min 5 54.34 /9/m~n 6 54 12 /5/mln 7

140La 1597 6 1.6785 /2/ d 1.6779/4/ d 8 1.6783/3/ d 9 1.6790/2/ d iO

143Ce 293 3 33.039 /6/ h 33.0 /2/ h 6 33.6 /24/ h ii

171Er 308 2 7.516 /2/ h 7.52 /3/ h 12 7.8 [2/ h 13 7.5 /2/ h 14

i77yb 150 2 1.911 /3/ h 1.8 /ii h 15 1.88 /i0/ h 16 1.9 / i/ h 17

186Re 137 3 3.775 /i/ d 3.775/13/ d 18 3.704/ 8/ d 19 3.867/ 8/ d 20 3.777/38/ d 21

188mRe 64 3 18.59 /4/ min 18.7 /2/ min 22 18.7 /3/ min 23

188Re 155 3 17.OO6/4/ h 16.98 /2/ h 21 16.9 /3/ h 24 16.7 /5/ h 25

386

ABZOUZI et al.: IMPROVED VALUES OF HALF-LIVES

REFERENCES

i. R.W. Bartholomew, F. Brown, W.D. Howell, W.R.J. Shorey, L. Yaffe, Can. J. Phys., 31 /1953/ 714.

2. P.O. Aronsson, B.E. Johansson, J. Rydberg, G. Skarne- mark, J. Alstad, B. Bergersen, E. Kvale, M. Skarestad, J. Inor~. Nucl. Chem., 36 /1974/ 2397.

3. T.B. Ryves, K.J. Zieba, J. Phys. A: Math. Nucl. Gen., 7 /1974/ 2318.

4. M. Dorikens, J. Demuynck, L. Dorikens-Vanpraet, Z. Phys., 244 /1971/ 321.

5. A.C. Graves, R.L. Walker, Phys. Rev., 71 /1947/ i.

6. J.F. Emery, S.A. Reynolds, E.I. Wyatt, G.I. Gleason, Nucl. Sci. Eng., 48 /1972/ 319.

7. K.H. Beckurts, M. Brose, M. Knocke, G. KrUger, W. P6- nitz, H. Schmidt, Nucl. Sci. Eng., 17 /1963/ 329.

8. K.F. Walz, K. Debertin, H. Schrader, Int. J. Appl. Radiatio D Isotopes, 34 /1983/ 1191.

9. H. Houtermans, O. Milosevic, F. Reichel, Int. J. Appl. Radiation Isoto~.es, 31 /1980/ 153.

i0. J.B. Olomo, T.D. MacMahan, J. Phys. G: Nucl. Phys., 6 /1980/ 367.

ll. M.L. Pool, N.L. Krisberg, phys. Rev., 73 /1948/ 1035.

12. F.P. Cranston, Jr., M.E. Bunker, J.W. Starner, Phys, Rev., Ii0 /1958/ 1427.

13. D.G. Megli, G.P. Agin, V.R. Potnis, C.E. Mandeville~ Nucl. Phys., AI07 /1968/ 217.

14. B.H. Ketelle, W.C. Peacock, Phys. Rev., 73 /1948/ 1269.

15. F.K. McGowan, Phys. Rev., 76 /1949/ 1730.

16. J.W. Cork, M.K. Brice, D.W. Martin, L.C. Schmid, R.G. Helmer, Phys. Rev., i01 /1956/ 1042.

17. J. Lindskog, T. Sundstrom, P.S. Sparrman, Arkiv. Fy- sik., 23 /1963/ 341;

387

ABZOUZ1 et al.: IMPROVED VALUES OF HALF-LIVES

18. G. Gueben, J. Govaerts, Inst. Interuniv. Sci. Nucl6- aires /Bruxelles/, Monographie No 2/1958/.

19. F.T. Porter, M.S. Freedman, T.B. Novey, F. Wagner, Jr., Phys. Rev., 103 /1956/ 921.

20. L.J. Goodman, M.L. Pool, Phys. Rev,, 71 /1947/ 288.

21. R. Michel, U. Herpers, Radiochim, Acta, 16 /1971/ 115.

22. K. Takahashi, M. McKeown, G. Scharff-Goldhaber, Phys. Rev., 136 /1964/ BI8.

23. A. Flammersfeld, Z. Naturforschun@, 8a /1953/ 217.

24. M. Lindner, J.S. Coleman, J. Am. Chem. Soc., 73 /1951/ 1610.

25. Ajzenberg-Selove, Nuovo Cimento, 4 /1956/ 2.

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