Selected Topics in Ultra-Low Emissivity Alpha-Particle Detection

In an effort to better understand the contribution of terrestrial protons to the counter background, we have developed a model to examine the production of protons, within an ionization counter from the interaction of incident neutrons on the counter material. Results of high energy proton irradiation on an UltraLo-1800 XIA alpha-particle counter are shown which indicate that the active signal discrimination is very effective at rejecting most of the detected events. A Poisson model is described which gives guidance on making appropriate measurement times and acceptance criteria for detectors with a range of backgrounds.