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DETERMINATION OF THE ACTIVATION CROSS SECTION OF SHORT-LIVED NUCLEAR ISOMERS FOR THERMAL NEUTRONS (in German)

Journal Article · · Ann. Physik
With the Rossendorf Research Reactor a method of pulse activation was developed for determining activation cross sections for short-lived isomeric nuclear states. Transition energies, half lives. and in some cases K conversion coefficients were measured for the isomer levels. The experimental equipment and method are described. The resuults are. for Na/sup 23/ (n, gamma )Na/sup 24m/, T/sup 1/2 = 20.3 plus or minus 0.2 msec an d sigma = 0.40 plus or minus 0.03 barn; for Ge/sup 70/(n, gamma )Ge/sup 71m/, T/sub 1/2 = 20/.0 P 0.6 msec and sigma = 0.28 plus or minus 0.07 barn; for Ga/sup 71/(n, gamma )Ga/sup 72m/, T/ sub 1/2/ = 36 plus or minus 1 msec and sigma = 0.15 plus or minus 0.05 barn; for Se/sup 76/(n, gamma )Se/sup 77m/, ; for In/sup 115(n, gamma ) In/sup 116m/, T/sub 1/2/ = 2.16 plus or minus 0.02 sec and sigma = 92 plus or minus 14 barn; for Er/sup 166/(n, gamma ) X Er/sup 167m/, T/sub 1/2/ = 2.27 plus or minus 0.05 sec and sigma = 15 plus or minus 2 barn; and for Yb/sup 174/(n, gamma )Tb/sup 175m/, T/sub 1/2/ = 67 plus or minus 1 msec and sigma = 46 plus or minus 4 ba rn. From the ratio of the activation cross section to the absorption cross section, conclusions on the spin of the nuclear state were drawn. For Ga/sup 72/ and In/sup 116/ new proposals for an energy level scheme were obtained. For the remaining nuclei the previous spin arrangements were confirmed. (tr-auth)
Research Organization:
Zentralinstitut fur Kernphysik, Rossendorf, Ger.
Sponsoring Organization:
USDOE
NSA Number:
NSA-18-015219
OSTI ID:
4073938
Journal Information:
Ann. Physik, Journal Name: Ann. Physik Vol. Vol: (7), 12
Country of Publication:
Country unknown/Code not available
Language:
German