Secondary-neutron-yield measurements by current-mode detectors

Secondary deuterium-tritium (DT) neutrons from pure-deuterium inertial conf inement fusion targets can be used to diagnose the fuel areal density. Sing le-hit detectors like LaNSA at Lawrence Livermore National Laboratory or ME DUSA at the Laboratory for Laser Energetics (LLE) saturate for fairly low s econdary DT- and primary DD-neutron yields. These detectors are not suitabl e for the high-yield, direct-drive implosion experiments currently carried out on the 30 kJ, 60 beam OMEGA laser system or for future cryogenic-capsul e experiments on OMEGA. The status of several current-mode detectors (e.g., a single scintillator and a photomultiplier tube) now being developed at L LE for secondary-neutron-yield measurements is described. (C) 2001 American Institute of Physics.