ZIP-ping for Dark Matter – Michael Dragowsky
Date: Mon. September 19th, 2005, 12:30 pm-1:30 pmLocation: Rockefeller 221
Astrophysical evidence has long implied the existence of non-luminous matter on the scale of galaxies. In the last few years experimental cosmology has emerged as a precision science, providing further evidence for non-luminous matter on extragalactic distance scales. The evidence points to matter that is non-baryonic and non-relativistic in nature. Detection of this so-called dark matter in terrestrial detectors via scattering from nuclei is feasible provided sufficiently low energy threshold and the means to suppress electron recoil backgrounds is achieved. The Cryogenic Dark Matter Search collaboration has developed novel detectors with these capabilities. Athermal phonon sensors are patterned by photolithography onto thick semiconductor absorbing substrates along with ionization electrodes. The ratio of energy collected from these two processes serves as an effective means to distinguish nuclear- and electron-recoil events. Background rejection is enhanced from use of phonon sensor timing parameters that reflect the underlying phonon physics in these semiconductor crystals operated at sub-Kelvin temperatures. Design considerations, fabrication, testing and performance of the CDMS Z-sensitive Ionization and Phonon (ZIP) detectors will be presented in this seminar, along with a brief review to motivate the search for dark matter.