Effect of Neutron-Induced Defects on the Current-Carrying Behavior of Vapor-Deposited Niobium Stannide

Abstract

The current-carrying capacity of vapor-deposited Nb3Sn can be increased by introduction of structural defects by neutron irradiation. The change in current density per unit of neutron flux is a function of the initial perfection of the material. The characteristics of low-α material (α≈J cH) are altered more than high-α material by irradiation. The current capacity of the material is eventually decreased by continued irradiation. The current behavior of material exhibiting an α less than 15 kG·A/cm2 can be described by a simple Lorentz force model. Material exhibiting an α higher than this is not adequately described by such a model. The electrical scattering cross section of a neutron-damaged area is calculated to be ∼4×10−12cm2.