Techniques for Head-Tail directional recoil measurements in the DRIFT-II dark matter detector

Abstract

We introduce the concepts and techniques relevant to determining evidence for the so-called Head-Tail asymmetry from neutron-induced nuclear recoil tracks in the DRIFT-II dark matter detector. The back-to-back dual TPC arrangement in DRIFT makes this detector ideal for Head-Tail tests, allowing systematic errors to be reduced. The detection of Head-Tail asymmetry can open a powerful new means of searching for a galactic signature from WIMPs. Identification of dark matter

First measurement of nuclear recoil head-tail sense in a fiducialised WIMP dark matter detector

“…The DRIFT collaboration has already demonstrated head-tail sensitivity using pure CS 2 target gas [18,24]. DRIFT chose to use this particular gas because it drifts signals as negative ions which results in much lower diffusion of tracks than can be achieved by conventional gases that drift electrons.…”