Optimized running conditions and sensitivity for direction sensitive detectors of WIMP dark matter

• Published in: Astroparticle physics 2011-12, Vol.35 (5), p.235-241
• Main Authors: Tatarowicz, J., Martoff, C.J.
• Format: Article
• Language: English
• Subjects: Direction sensitive dark matter detection; Gas detector; WIMP wind
• ISSN: 0927-6505; 1873-2852
• DOI: 10.1016/j.astropartphys.2011.06.012

► Maximization of specific event rate for direction-sensitive dark matter detectors. ► Optimum pressure found based on minimum resolvable track length and gas fill. ► Optimum fill pressures found for Ar, Xe, CS 2 and CF 4. ► Volumes to achieve competitive WIMP-nucleon cross-section sensitivity are calculated. Optimum fill pressures for direction-sensitive dark matter detectors based on tracking in gases are considered. Given the minimum resolvable track length and the gas fill, the Lindhard–Scharf stopping model leads to the existence of an optimum pressure which maximizes the specific event rate R (event rate per unit detector volume). In addition, maximizing the detectibility of the recoil nucleus diurnal asymmetry is considered. Optimum fill pressures are calculated for Ar, CF 4, CS 2 and Xe gas fills, as a function of the WIMP mass and the minimum resolvable track length. The associated minimum target volumes required to achieve currently competitive WIMP-nucleon cross-section sensitivity are also calculated. The standard isothermal sphere model of the galactic WIMP halo is used throughout, but the method could be extended to use any desired WIMP distribution function.