CSCSeminar DATE: 2006-10-13 10:00 - 12:00 PLACE: 4 Goukan Ground Floor Meeting Room TITLE: ULTIMA Project : Particle detector with working temperature 100 μK CONTACT: 　Kiyosumi TSUCHIYA 864-5453 / kiyosumi.tsuchiyakek.jp SPEAKER: Dr. Y. M. Bunkov  (CRTBT-CNRS, Grenoble / ISSP, Tokyo University) LANGUAGE: English ABSTRACT: The project ＜Ultra Low Temperature Instrument for Measurements in Astrophysics > (ULTIMA) based on a new target material for bolometric particle detection; superfluid 3He-B at ultra-low temperatures of the order of 100 μK. At these temperatures the quantum excitations in 3He are nearly all frozen and its heat capacity virtually approaches zero. Superfluid 3He has many advantages as a detector of low energy elementary particles. It has very small heat capacity, direct channel of measurements of deposited energy, absolute purity, etc. We have tested the detector with neutron, cosmic muon and secondary electron detection. Superfluid 3He detector can be considered as a candidate for Dark matter detection. The main arguments in favour of 3He are its non-zero nuclear magnetic moment (allowing therefore to explore the Spin-Dependent interaction channel) combined to the extremely high sensitivity of superfluid 3He bolometers and the possibility of efficient neutron background discrimination. Back