Detector Development for Direction-Sensitive Dark Matter / Neutron Research

by Dr Hidefumi Tomita (Boston University)

Tuesday Dec 6, 2011, 3:30 PM → 4:30 PM Pacific/Honolulu

415A (Watanabe Hall)

Preliminary Abstract: There is now little doubt that Dark Matter exists. However, because Dark Matter is expected to interact very weakly through non-gravitational forces, nothing is known about the nature of Dark Matter. It is believed that Dark Matter particles are streaming toward the Earth, in the Earth's rest frame, from the direction of the constellation Cygnus. Observation of this so-called Dark Matter “wind” with a direction-sensitive dark matter particle detector would be compelling evidence that Dark Matter does consist of a gas of discrete particles as a new form of matter. The DMTPC collaboration is developing such a detector. The DMTPC technique for looking for Dark Matter relies on Dark Matter particles interacting with atomic nuclei, causing the nuclei to recoil and to leave optical signals that can be detected. Since neutrons are electrically neutral and collide with nuclei, they can mimic Dark Matter signals. Therefore, the reduction of neutron background is critical to the successful detection and identification of Dark Matter particles. Such a detector development also allows us to understand how our device can be used as a neutron detector. We have been able to measure a number of neutron events in a variety of experimental runs – both with and without neutron sources such as a Cf-252. From these runs, we have obtained data for both elastic and inelastic interactions of neutrons of various energy ranges with detector gas nuclei.