25 ps neutron detector for measuring ICF-target burn history

Abstract

We have developed a fast, sensitive neutron detector for recording the fusion reaction-rate history of inertial-confinement fusion (ICF) experiments. The detector is based on the fast rise time of a commercial plastic scintillator (BC-422) and has a response <25 ps FWHM. A thin piece of scintillator material acts as a neutron-to-light converter. A zoom lens images scintillator light to a high-speed (15 ps) optical streak camera for recording. A retractable nose cone positions the scintillator between 1 and 50 cm from a target. A simultaneously recorded optical fiducial pulse allows the streak camera time base to be calibrated relative to the incident laser power. Burn histories have been measured for deuterium-tritium filled targets with yields ranging between 108 and 2×1013 neutrons.