First dark matter limits from a large-mass, low-background, superheated droplet detector

We report on the fabrication aspects and calibration of the first large act ive mass (similar to 15 g) modules of SIMPLE, a search for particle dark ma tter using superheated droplet detectors (SDDs). While still limited by the statistical uncertainty of the small data sample on hand, the first weeks of operation in the new underground laboratory of Rustrel-Pays d'Apt alread y provide a sensitivity to axially coupled weakly interacting massive parti cles (WIMPs) competitive with leading experiments, confirming SDDs as a con venient, low-cost alternative for WIMP detection.