Identification of low energy nuclear recoils in a gas TPC with optical readout

Abstract

The search for a novel technology able to detect and reconstruct nuclear recoil events in the keV energy range has become more and more important as long as vast regions of high mass WIMP-like Dark Matter candidate have been excluded. Gaseous Time Projection Chambers (TPC) with optical readout are very promising candidate combining the complete event information provided by the TPC technique to the high sensitivity and granularity of last generation scientific light sensors. A TPC with an amplification at the anode obtained with Gas Electron Multipliers (GEM) was tested at the Laboratori Nazionali di Frascati. Photons and neutrons from radioactive sources were employed to induce recoiling nuclei and electrons with kinetic energy in the range [1-100] keV. A He-CF4 (60/40) gas mixture was used at atmospheric pressure and the light produced during the multiplication in the GEM channels was acquired by a high position resolution and low noise scientific CMOS camera and a photomultiplier. A multi-stage pattern recognition algorithm based on an advanced clustering technique is presented here. A number of cluster shape observables are used to identify nuclear recoils induced by neutrons originated from a AmBe source against X-ray 55Fe photo-electrons. An efficiency of 18% to detect nuclear recoils with an energy of about 6 keV is reached obtaining at the same time a 96% 55Fe photo-electrons suppression. This makes this optically readout gas TPC a very promising candidate for future investigations of ultra-rare events as directional direct Dark Matter searches.

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Cited by in corpus (7)

• The CYGNO Experiment
• Observables for Recoil Identification in High-Definition Gas Time Projection Chambers
• Directionality and head-tail recognition in the keV-range with the MIMAC detector by deconvolution of the ionic signal
• The role of small scale experiments in the direct detection of dark matter
• Enhancing the light yield of He:CF${}_4$ based gaseous detector
• Bayesian network 3D event reconstruction in the Cygno optical TPC for dark matter direct detection
• LIME -- a gas TPC prototype for directional Dark Matter search for the CYGNO experiment