出版社：SISSA, Scuola Internazionale Superiore di Studi Avanzati
摘要：The neutron spectrometer ROSPEC is made up of 6 spherical proportional counters with different
gas fillings, on a rotating platform, and which covers the energy range 0.025 eV to 4.5 MeV.
A complete study is performed within the framework of a French working group in order to
improve the spectrometer performance. First, the study of the devices performance in reference
neutron fields was performed, with respect to the influence of rotation and disturbance from other
counters. It appeared that the fluence scattered by other counters could represent between 7
and 40% of the total fluence, but with a slight influence on the initial spectrum. Secondly, we
determined the response matrix for each counter from two main parameters, the wall and the gas
amplification effects. The wall effects were calculated using the Snidow algorithm and compared
to the MCNPX simulation. The change in the electric field was calculated using a finite element
method to define amplification region for simulation. Finally, since the ROSPEC unfolding code
sometimes gave negative fluences, the unfolding code UMG was used to correct this default. We
compared the results from both unfolding codes.
