Fast Neutron Damage Studies on NDFEB Materials

Abstract

Many materials and electronics need to be tested for the radiation environment expected at linear colliders (LC) since both accelerator and detectors will be subjected to large fluences of hadrons, leptons and γ's over the life of the facility [1]. While the linacs will be superconducting, there are still many uses for NdFeB in the damping rings, injection and extraction lines and final focus. Our understanding of the situation for rare earth, permanent magnet materials was presented at PAC03 [2]. Our first measurements of fast neutron, stepped doses at the UC Davis McClellan Nuclear Reactor Center (UCD MNRC) were presented at EPAC04 [3]. We have extended the doses, included other manufacturer's samples, and measured induced radioactivities which are discussed in detail.

Materials Degradation and Detection (MD2): Deep Dive Final Report

“…Neutron damage studies of magnetic sensor materials are few and far between (see Appendix for an incomplete summary), and results indicate a wide range of behaviors, including amorphization (Chukalkin et al 1983), cation site mixing (Chukalkin et al 1975), superparamagnetism (Parkhomenko et al 1976), anisotropy change (Chukalkin et al 1981), loss of remnance (Anderson et al 2005), or complete loss of magnetization due to radiation-induced thermal spikes (Liu et al 2007). In addition to their use in magnetostrictive transducers, magnetic materials are integral to the operation of linear variable differential transformers (LVDTs), which will also find future use as in-pile diagnostic instruments ).…”