Prospects for SIMPLE 2000: a large-mass, low-background superheated droplet detector for WIMP searches

The Superheated Instrument for Massive Particle searches (SIMPLE 2000) will consist of an array of 8-16 large active mass (similar or equal to 15 g) s uperheated droplet detectors (SDDs) to be installed in the new underground laboratory of Rustrel-Pays d'Apt. Several factors make the use of SDDs an a ttractive approach for the detection of weakly interacting massive particle s (WIMPs), namely their intrinsic insensitivity to minimally ionizing parti cles, high fluorine content, low cost and operation at near ambient pressur e and temperature. We comment here on the fabrication, calibration and alre ady-competitive first limits from prototype SDDs for SIMPLE, as well as on the expected immediate increase in sensitivity of the programme, which aims at an exposure of >25 kg day during 2000. The ability of modest-mass fluor ine-rich detectors to investigate regions of neutralino parameter space bey ond the reach of the most ambitious cryogenic projects is pointed out.