Thermal Neutron Capture Cross Section of ²³²Pa

Abstract

There are measured radiation capture cross-sections of neutrons σ_n,γ(²³²Pa) caused by a short-lived (T_1/2=31.44 hour) nucleus of ²³²Pa near the thermal point. The samples of ²³¹Pa weighing ~50 μg were irradiated in a flux of neutrons of IRT reactor (MEPI, Moscow). σ_nγ was calculated as related to the amount of built up in the course of irradiation atoms of ²³²Pa and ²³³Pa (T_1/2=27 day). The build-up of ²³²Pa and ²³³Pa was defined by the results of irradiated samples γ-spectrometry performed with the use of radiometric measurement complex belonging to MEPI. The contribution of epicadmium neutrons was taken into account as to ²³³Pa build-up in the samples of ₂₃₁Pa irradiated in cadmium cases.

Thermal neutron capture cross section of ²³²Pa constituted σ_th=(655±69) bam.

Keywords:

• protactinium 231
• protactinium 232
• protactinium 233
• activation
• reactor
• ϒ-spectrometry
• Ge- detector
• capture cross section