Simultaneous measurements of DT fusion gamma-ray and neutron-induced secondary gamma-ray using Gas Cherenkov Detector

A Gas Cherenkov Detector (GCD) which captures 16.75 MeV DT fusion gamma-rays has been developed by Los Alamos National Laboratory in collaboration with Lawrence Livermore National Laboratory and Atomic Weapons Establishment. Due to the fast time response, the GCD will be an essential instrument for National Ignition Facility (NIF) fusion reaction history studies. A challenge faced by the GCD is potential interference of primary DT fusion gamma-rays (gamma_p) with various secondary gamma-rays ( gamma_s). NIF implosions produce 14 MeV DT neutrons (n_o) that induce the production of gamma_s from reactions on capsule materials (¹²C, ¹⁶O) and hohlraum materials (Au, U, Al). Experimental characterization of the GCD responses to various gamma rays is required for accurate measurements of NIF fusion reaction history. The experimental goal of this paper is to simulate the neutron-induced secondary gamma production of a NIF hohlraum.