R&D of a SIMPLE bubble chamber for dark matter searches

SIMPLE (Superheated Instrument for Massive ParticLe Experiments) intends the realization and full field tests of a 25 kg, low background, low frequency-instrumented BC (Bubble Chamber), with data from the BC testing and a small array demonstration providing new physics results. We report on the development of a 1 kg freon BC prototype, including chamber recompression system design and testing with initial acoustic detection of bubble formation. Realization of full field tests leading to a 25 kg, overall 10−6 recoil evt/kgF/d background, low frequency-instrumented BC, incorporating several innovations designed, are intended to serve for an anticipated 2500 kgd exposure, resulting in new exclusion contours with sensitivities of 2 × 10−8 and 5 × 10−5 pb at 35 GeV in the SI and SD sector of the WIMP phase space, respectively.