POTENTIAL DARK-MATTER DETECTOR - THE DETECTION OF LOW-ENERGY NEUTRONSBY SUPERFLUID HE-3

Using an existing experiment we have demonstrated in a pilot study tha t superfluid He-3 at 100 mu K can be used as a nuclear recoil detector sensitive to neutron and gamma interactions depositing energies down to a few hundred eV. The deposited energy is converted to He-3 quasipa rticles which are detected by their damping effect on a vibrating wire resonator in the liquid. The system can be calibrated independently b ut a convenient fixed point is provided by the exothermic reaction n He-3(2) = p + H-3(1) + 764 keV. Given the great potential for improve ment we propose that the system might make a sensitive weakly interact ing massive particle detector.