Activation of high-T sub(c) superconductors with neutron irradiation

Activation due to nuclear transmutation is a very important factor for feasibility evaluation on the improvement of superconducting property by neutron irradiation. In this paper, the activation of Bi sub(2)Sr sub(2)CaCu sub(2 )O sub(8+x) (Bi-2212) superconductor was evaluated by the activation analysis and calculation using ORIGEN-JR computer code. The activation analysis was carried out to determine the composition and impurity concentrations of the specimen. Then, based on the data about impurities, the contribution of the impurities and the decay of radioactivity after irradiation were calculated. Main elements for activation were Sr as a component of Bi-2212, and Co, Zn and Fe as impurities. Activation caused by the impurities occupied 40% 1 year after irradiation. When thermal neutron flux was reduced by 80% using a Cd filter, the total activation was reduced to about 30%. copyright 2002 Published by Elsevier Science B.V.