Detection and imaging of 2-100 keV x-rays and thermal neutrons

This work is concerned with two important types of radiation detectors, proportional counters and microchannel plates. The work on proportional counters, which represents the major part of this thesis, was carried out using a Single Wire Proportional Counter (SWPC) and Microstrip Proportional Counter (MSPC). The behaviour of both of the counters at high gas pressures was investigated using different Xenon-based gas mixtures. The results of measurements using the SWPC and MSPC were presented in terms of gas gain and energy resolution. The measured gas gain was compared with theory using the Diethorn formula. The validity and feasibility of the formula at high pressures were discussed in connection with the experimental measurements. The results showed the importance of the gas filling used and geometry of proportional counters.;The study carried out on the Microchannel Plates (MCPs) introduced a thermal neutron imaging detector based on the use of a combination of standard glass MCPs and gadolinium foil. The measurements of detection efficiency and spatial resolution of the MCP-Gd detector were reported. It was shown that such a combination produces a thermal neutron imaging detector with useful efficiency and good spatial resolution.