Scintillator detectors in inertial confinement fusion experiments are predominantly used to measure neutron yield and ion temperature of the primary fusion reactions. The detection of neutrons in fast-ignition experiments is very challenging since it requires the neutron detection system to recover within 100 ns from a high background orders of magnitude stronger than the signal of interest. Liquid scintillator with different compositions was investigated. We present several designs of liquid scintillator using the Geant4 Code and the X-Lab Code. Our liquid scintillator is based on PPO, dissolved in xylene and enriched with molecular O₂. The detector consists of a 2-3 liters volume of liquid scintillator coupled to a gated MCP. A small air bubble allows for thermal expansion of the liquid without a significant pressure increase. The gating performance under high-intensityγrays was experimentally checked. The typical flight time spectrum of the neutrons from (p,n) reaction driven a PW laser is shown in Fig.1. The neutron yield in the fast ignition experiments on Shenguang-II laser facility was successfully measured using this detector. In fast ignition experiments, a PW laser beam was employed to produce high intense electron beams to ignite the compressed fuel. Our neutron detection system could suppress the background signal and eliminate the afterglow present in conventional plastic scintillators.
 

Liquid Scintillator,Fast neuton