Study of cylindrical, energy-proportional pulse-height detectors for measuring microdosimetric quantities

A study has been carried out on the use of cylindrical, energy-proportional pulse-height detectors for determining microdosimetric quantities. In this paper we report the results of using a Hurst chamber to obtain neutron LET spectra and a commercial CH/sub 4/ chamber to obtain neutron energy spectra. This work represents an extension of our earlier application of Monte Carlo techniques to the unfolding of LET spectra. The method depends on knowledge of the track-length distribution of charged particles in the chambers, coupled with the measured pulse-height spectra. By several examples it is shown that LET spectra inferred from measurements with the Hurst chamber do not depend critically on the track-length distribution. Calculations for monoenergetic neutrons incident in the CH/sub 4/ chamber show that it provides a good energy resolution up to approx. 2 MeV. Comparisons are made of the effects of different assumptions about the direction of the incident neutrons on the unfolded energy spectrum. Results are presented of neutron energy spectra unfolded from measurements made with the CH/sub 4/ chamber exposed to neutrons from the Health Physics Research Reactor.