Evaluation of reconstruction methods for time-resolved spectroscopy of short-pulsed neutron sources

A comparison of five methods for the reconstruction of the time-resolved neutron energy spectrum of short-pulsed neutron sources from time-of-flight measurements is reported. The first method is an analog Monte Carlo reconstruction technique (AMCRT), expressly designed for the optimization of such measurements. It was proved that the studied problem can be treated as a tomographic one with a limited data set. A Fourier convolution and backprojection method and three other tomographic methods, which have been shown to work with a limited data set, are used: the maximum entropy method, the algebraic reconstruction technique, and a Monte Carlo implementation of the backprojection (MCBP) technique. Through numerical tests, the quality of reconstructions in different image geometries at various noise levels has been studied. Besides the AMCRT method, which produces the best results, good reconstructions are also obtained using MCBP and maximum entropy. If computing time must be minimized, the maximum entropy algorithm is most convenient. This algorithm could be used routinely in time-resolved spectroscopy measurements