Simulations of the Nuclear Recoil Head-Tail Signature in Gases Relevant to Directional Dark Matter Searches

Abstract

We present the first detailed simulations of the head-tail effect relevant to directional Dark Matter searches. Investigations of the location of the majority of the ionization charge as being either at the beginning half (tail) or at the end half (head) of the nuclear recoil track were performed for carbon and sulphur recoils in 40 Torr negative ion carbon disulfide and for fluorine recoils in 100 Torr carbon tetrafluoride. The SRIM simulation program was used, together with a purpose-written Monte Carlo generator, to model production of ionizing pairs, diffusion and basic readout geometries relevant to potential real detector scenarios, such as under development for the DRIFT experiment. The results clearly indicate the existence of a head-tail track asymmetry but with a magnitude critically influenced by two competing factors: the nature of the stopping power and details of the range straggling. The former tends to result in the tail being greater than the head and the latter the reverse.

22 pages, 12 figures, submitted to Astroparticle Physics

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Cited by in corpus (13)

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• Directional recoil detection
• Introduction to dark matter experiments
• Three-dimensional track reconstruction for directional Dark Matter detection
• Reconstructing the three-dimensional local dark matter velocity distribution
• Time-integrated directional detection of dark matter
• First measurement of nuclear recoil head-tail sense in a fiducialised WIMP dark matter detector
• Directional detection of Dark Matter
• Simulations of the 3-Dimensional Velocity Distribution of Halo Weakly Interacting Massive Particles for Directional Dark Matter Detection Experiments
• Measurement of directional range components of nuclear recoil tracks in a fiducialised dark matter detector