Electromagnetic radiations of cesium-132.
by Robinson, Berol L.; Fink, Richard W.
cf. C.A. 50, 10547h. Cs132 was prepd. by bombardment of CsCl with 80-m.e.v. protons followed by radiochem. purification. The half-life by ?-counting was 6.2 ± 0.2 days. ?-Rays at 669 ± 3, 1100 ± 40, and 1265 ± 20 e.kv., with intensities of 1000:(7 ± 2):(8 ± 2), resp., were found by scintillation spectrometry. By means of K x-ray-?-coincidences, the branching ratio to the 669-e.kv. level was found to be 0.9-0.2+0.1, in agreement with shell model predictions. The transition to the ground state thus is forbidden, and, because the ft value shows the transition to the 669-e.kv. level to be allowed, the spin of Cs132 must be either 2 or 3. ?-? coincidences were observed, but the 1265-e.kv. ?-ray is not coincident with 669-e.kv. radiation. By calibration of ?-ray energy against Na22 standard, it was shown that the 1400-e.kv. transition in I132 decay has energy 1400 ± 10 e.kv. and thus does not correspond to the 1265-e.kv. transition in Cs132 decay. ?-Rays at 395 ± 10 and 550 ± 30 e.kv., with intensities of about 4:1, resp., decayed with a 31-hr. half-life and are, therefore, assigned to Cs129.