Abstract
Proton bombardment of Pd produces the three known Ag periods of 2.3 min. (), 25 min. and 8 days (), and three new periods of 16.3 min. (+), 73 min. (+) and 45 days ( capture). The latter are assigned tentatively to , , and , respectively. Excitation functions for the isomeric 25-min. and 8-day periods give thresholds of 3.8 and 3.9 Mev, respectively. The former agrees with the known positron spectrum of the short period. The higher threshold for the 8-day period indicates that this state lies above the 25-min. state. This activity is accompanied by probably three gamma-rays of which two of 0.62 and 1.06 Mev have been identified with a beta-ray spectrograph. Since no positrons accompany this activity it must decay mainly by -electron capture to rather than to the lower isomeric state. Four gamma-rays of about 0.29, 0.42, 0.50, and 0.69 Mev accompany the 45-day period.
- Received 11 September 1939
DOI:https://doi.org/10.1103/PhysRev.56.872
©1939 American Physical Society