Relativistic effect on atomic displacement damage for two-body inducing discrete reactions

¹ CEA, Cadarache, DEN/DER/SPRC/LEPh, 13108 Saint Paul Les Durance, France
² I-MEP2, University Grenoble Alpes, 38402 Saint Martin d'Heres, France

^* e-mail: shengli.chen@cea.fr

Published online: 30 September 2020

Abstract

The relativistic effect on two-body discrete reaction inducing atomic recoil energy and the sequent damage energy is studied for ⁶Li, ⁵⁶Fe, ¹⁸⁴W, and ²³⁸U. The relativistic correction is within 1% if incident neutron energy is below 20 MeV. For incident neutron energy up to 200 MeV or even 800 MeV, the relativistic effect should be taken into account for treating two-body kinematics. The relativistic correction is about 0.05E_in/MeV% for neutron elastic scattering for nuclei from ⁵⁶Fe to ²³⁸U and smaller for (n,α) and (n,t) reactions. Analyses on damage energy show that the relativistic corrections are generally within 2% for incident neutron below 200 MeV for nuclei lighter than ⁵⁶Fe because of the “saturation” of damage energy. However, the current damage theory cannot be applied for Primary Knock-on Atom (PKA) energy higher than 24.9A_RZ_R^4/3 keV, which is 10 times lower than the maximum PKA energy for D+T fusion neutron elastic scattering of ⁶Li.