Coloquios INC; Blás Cabrera 12 de febrero 12:30
Title: The search for dark matter with ultra-low temperatures detectors
When: Wednesday, 12 February, 12h30
Where: Sala de conferencias, módulo 00, Facultad de Ciencias
Speaker: B. Cabrera (Stanford)
Abstract: Many astrophysics observations have now convinced us that mos of the mass of the universe is in a mysterious form called dark matter. This talk gives a brief overview of the search for dark matter. We then discuss the techniques used by de SuperCDMS (cryogenic dark matter search) experiment in the search for dark matter in the form of weakly interacting massive particles or WIMPs. Crystals of Si and Ge are cooled to within 0.05 degrees of absolute zero. For each interaction event with gamma rays, neutrons and potentially WIMPs, both the heat and the ionization are measured, allowing an event by event discrimination of electron recoils (produced by gamma rays) and nuclear recoils (produced by neutrons and WIMPs). These measurements take advantage of lattice vibrations or phonons in the crystals, qusiparticle produced by disociate Cooper pairs in superconductivity in Al films, and finally superconducting transition edge sensors used to measure the heat.