Development of low temperature nuclear recoil detectors for the UK dark matter experiment

Low temperature nuclear recoil detectors are being developed to search for relic weakly interacting particles in the mass range 1-104 GeV, in particular, the hypothetical photino. Materials with both zero and non-zero nuclear spin and a range of nuclear masses are being investigated, e.g. Si, GaAs and LiF. The detector array will have a total mass of around 1-2 kg giving event rates typically of 1-102 d-1. Thermal pulses due to photons interacting down to 2 keV have so far been observed with sensitivities better than l keVg-1 in targets with masses in the range 1-32 g using commercial Ge sensors. Progress has been made in manufacturing techniques to enable mass production of quantities of doped silicon resistance thermometers with reproducible resistance-temperature characteristics suitable for attachment to the many target crystals needed for the detector array. NTD germanium sensors are also being investigated. (author) 5 refs.; 5 figs.; 1 tab