The development of millikelvin Ge and Si bolometers for the UK dark matter programme

Thermalized phonon bolometers are being developed for the UK Dark Matter Telescope project. Initial work was based on the use of ion implanted Si:As bolometers and commercial Ge devices. The implanted devices were found to suffer from hot electron effects at very low temperature and the commercial Ge sensors lack the uniformity of NTD devices. New epitaxial Si sensors are being developed together with NTD Ge sensors, as a replacement for the current ion implanted devices. This would allow the application of such thin film bolometers to exotic particle detection which was one of the reasons that prompted the initial work in this area. (R.P.) 14 refs.; 5 figs