INTERPRETATION OF NEUTRON TIME-OF-FLIGHT SIGNALS FROM CURRENT-MODE DETECTORS

Neutron time-of-flight (nToF) signals from current-mode neutron detect ors are often used to determine burn-averaged ion temperature from ICF targets because the spread of the neutron energy distribution is a fu nction of the temperature of the reacting ions. The measured signal wi ll, however, be a convolution of the actual neutron signal, the detect or response, and the response of the recording system. In addition, sc attered neutrons will arrive at the detector later than unscattered ne utrons, further broadening the signal. The ion temperature derived fro m nToF data depends strongly on the functions used to fit the data or the methods utilized to unfold the neutron energy spectrum. A function al form based on known and measured properties of the detectors is use d to fit the integral of the time-of-flight signal, allowing ion tempe rature derivations from targets with lower neutron yield than previous ly possible.