Neutron and photon spectrometry in monoenergetic neutron fields

In monoenergetic neutron fields (144 keV<En<19 MeV), spectrometry was performed for prompt photons as well as for scattered neutrons and for neutrons produced by nuclear reactions. Time-of-flight (TOF) experiments with NE213 scintillation detectors were carried out, and spectral fluences were obtained from the unfolding of the measured pulse height spectra. Doses of the prompt photons were calculated and compared with those obtained by measurements with Geiger–Müller counters (GM). The differences between both are remarkable, and they are for most fields due to the energy dependence of the GM response for high-energy photons. For the neutrons straightforward unfolding of a spectrum recorded without TOF selection and containing in its major parts also the response of neutrons with En>8 MeV is, however, hampered due to insufficient simulation of the response functions in regions where α-particles from the 12C(n,n′)3α reaction dominate the light output.