THE EFFECT OF TEMPERATURE ON THE NEUTRON ENERGY THRESHOLDS OF BUBBLE TECHNOLOGY INDUSTRIES BUBBLE DETECTOR SPECTROMETER

The adverse effect of temperature on the response of bubble detectors has been observed by most users. This phenomenon has hindered in parti cular, the use of the bubble detector spectrometer (BDS) in a variety of environments where temperatures are poorly controlled. An extensive study has been conducted to quantify temperature related effects. The primary investigation evaluated the responses of bubble detectors hel d at precisely controlled temperatures irradiated by monoenergetic neu trons produced by the 3 MeV KN Van de Graaff accelerator at the Defens e Research Establishment Ottawa. A series of 393 experiments were cond ucted over a two week period. The results reveal that the dominant con tributor to the increases in sensitivity observed at temperatures abov e 20-degrees-C is the downward shift in the detectors' neutron energy thresholds. These shifts invalidate the response matrix currently reco mmended for deconvoluting spectral data obtained with the BDS. As spec ified by the supplier, the current algorithm is only valid for measure ments conducted at 20-degrees-C. This paper presents the experimental data and associated uncertainty analysis.