Effects of 14-MeV neutron irradiation on optical components for fusion diagnostics

Abstract

Various kinds of optical fibers and related optical components for fusion diagnostics were irradiated with 14-MeV neutrons from OKTAVIAN or RTNS-II. This report shows typical fusion neutron irradiation effects on them and their hardness levels to mean 14-MeV neutron fluences at which their important performance degrades 10%. Also experimental formulas for fusion neutron induced backgrounds of scintilators and a photomultiplier tube are given by fitting their pulse height distributions for 14-MeV neutrons with a summation of exponential functions. These data and formulas are useful for the estimation of lifetimes and background levels of optical fusion diagnostic systems which may be located in the 14-MeV neutron environment of a fusion reactor.