A testing strategy for the mass production of CDMS II detectors

The Cryogenic Dark Matter Search (CDMS) employs detectors which are capable of simultaneously measuring the ionization and phonon energies deposited by a particle collision. These detectors are 1-cm-thick, 7-cm-diameter crystals of either germanium or silicon with a thin film of aluminum and tungsten patterned on the surface. This presentation discusses the testing regimen that a typical CDMS detector undergoes before it gets approval for final installation at the CDMS II deep site in Soudan, MN which will come online in early 2002. Now that our technology is relatively stable, the main focus of our test facilities is to provide quality control for the mass production of our detectors. First, the critical temperatures of the tungsten and other basic quantities are measured in preparation for iron implantation, which will bring the Tc down to the desired range ( 70 mK). The same basic measurements are taken again after implantation to assure that the correct Tc was achieved. Finally, a detailed map of energy response as a function of position is made to calibrate residual inhomogeneities across the surface.