GEOMETRY COMPENSATION FOR IMPROVING SPEED AND EFFICIENCY OF SCINTILLATOR-BASED NEUTRON TIME-OF-FLIGHT DETECTORS

Scintillator-based neutron detectors record time-of-flight (TOF) information used for estimating inertial-confinement-fusion plasma temperatures. Nova TOF detectors, which have 1.3 ns resolution and contain 30 cm3 of scintillator, lack the combination of temporal resolution and sensitivity necessary to measure 1 keV temperatures for deuterium plasmas emitting fewer than 1.5 X 10(9) neutrons. Significant time dispersion is caused by neutron detection-point uncertainty in thick scintillators. We describe a geometrical compensation technique by which this dispersion can be substantially reduced while retaining large scintillator volume. We estimate that scintillator/streak camera detectors can achieve 100 ps resolution for 2.45 MeV neutrons, and that scintillator/photomultiplier systems can achieve 150-300 ps resolution.