Radioactive Products from Gases Produced in Uranium Fission

Abstract

Some radioactive products from the gases produced in the fission of uranium by slow neutrons have been studied as to their chemical identity and characteristic half-life periods. Two Rb activities have been observed, one of which decays with a period of 15.4±0.2 minutes into an active Sr with a half-life of 51±2 days; the other decays with a period of 17.8±0.2 minutes into an apparently inactive end product. The parent of the 15.4-minute Rb is a gas with a half-life of a few minutes whereas the other Rb arises from the decay of a 175±10-minute Kr. Absorption in Al indicates the maximum $\beta$-particle energy for these active products to be 3.8 Mev for the 15.4-minute Rb and 4.6 Mev for the 17.8-minute Rb. In a similar manner, a Cs has been observed which decays with a 32±0.5-minute period into a Ba which is inactive or of very long or short period with no evidence of the 300-hour product reported by Hahn and Strassmann. Data have been obtained which indicate that this long period Ba arises from the decay of a product of a very short period gas. This 32-minute Cs results from the decay of a Xe with a half-life of 17±1 minutes. Absorption in Al indicates a maximum $\beta$-particle energy of 2.6 Mev for this Cs activity.