Superheated superconducting granule detectors for dark matter

Abstract

The response of Superheated Superconducting Granule (SSG) devices to nuclear recoils has been explored by irradiating SSG detectors with a 70MeV neutron beam. In the past we have tested Al SSG and more recently, measurements have been performed with Sn and Zn detectors. The aim of the experiments was to test the sensitivity of SSG detectors to recoil energies down to a few keV. In this paper, the preliminary results of the neutron irradiation of a SSG detector made of Sn granules 15-20µm in diameter will be discussed. For the first time, recoil energy thresholds of ∼1keV have been measured.

Cryogenic particle detectors

“…Encouraged by this result the Bern group proposes a prototype experiment for a cold dark matter search [Abp94]. As has been pointed out in section 2, a convincing signature in any cold dark matter experiment would be a seasonal modulation of the count rate [Dru86].…”

“…The Bern group and collaborators (ORPHEUS) is planning to set up a prototype dark matter detector in the University of Bern underground laboratory which has a cosmic ray reduction of 70 m water equivalent [Abp94,Abp95c]. The detector will consist of 1-2 kg of Sn granules with an average grain size of 10 µm and is supposed to be operated at a magnetic threshold H /H = 0.5%.…”