Several directional techniques have been proposed for a directional detection of Dark matter, among others anisotropic crystal detectors, nuclear emulsion plates, and low-pressure gaseous TPCs. The key point is to get access to the initial direction of the ion recoiling due to the elastic scattering by a WIMP. In this article, we aim at estimating, for each method, how the information of the recoil track initial direction is preserved in different detector materials. We use the SRIM simulation code to emulate the motion of the first recoiling ion in each material. We propose the use of a new observable, D, to quantify the preservation of the initial direction of the recoiling ion in the detector. We show that for an emulsion and an anisotropic crystal detector, the initial direction is lost very early, while for a typical TPC detector, the direction is well preserved. A gaseous TPC seems better suited to achieve the measurement of the direction of WIMP-induced nuclear recoils.
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