Directional Detection Of Galactic Dark Matter With A MIMAC Detector

Non-baryonic Dark Matter is currently one of the most important research topics in particle physics,cosmology and astrophysics.As the most popular non-baryon dark matter candidate,weakly interacting massive particles(WIMPs)are the main search target of mainstream Dark Matter direct detection experiments.If a WIMP candidate signal is detected,directional Dark Matter detection will eventually confirm that the dark matter signal comes from the Galaxy.We used prototype detectors of the Micro-tpc Matrix of Chambers(MIMAC)to per-form a series of feasibility studies for directional detection of Dark Matter with this type of detector.The work described in this thesis is a first Chinese contribution in Dark Matter di-rectional detection experimental research.We also designed and completed the set-up of a 25 cm experimental system,commissioning of electronics and vacuum systems,and perform energy calibration with an X-ray generator.A pipeline for the data analysis for the time projection chamber(TPC)and Micro Mesh Gaseous Structure(Micromegas)readout has been established.We independently developed a cross-platform visualization software for event display,which helps to im-prove the efficiency of monitoring the detector operating status and physical events iden-tification.We have performed noise analysis,energy calibration,and quenching factor measurement for the MIMAC prototype.One of our main tasks is to study the property of the Fluorine recoil tracks.Using prototype detectors with 5 cm and 10 cm drift distances,coupled to ion facilities,we com-pleted the three-dimensional track reconstruction and length measurement for ke V kinetic energy Fluorine ion.Such a measurement has been achieved for the first time in the world in a TPC with a Micromegas readout whose amplification gap is 512m.Moreover,we also report on the energy-dependent angular resolution of the MIMAC detector in the ke V energy range.Considering diffusion and other physical processes taking place in a MI-MAC detector,we reconstruct the ion tracks which are a few mms in length.We propose a correction on the track depth based on the charge collection rate asymmetry and well explained the discrepancy between the simulations and the measurements.For kinetic energy down to 10 ke V,we obtained an angular resolution for the MIMAC detector to be12.4°,which is better than required for an efficient Dark Matter directional detector.Several machine learning algorithms have been used to study the electron/ion event discrimination in the high-gain mode.Combining the null result of the head-tail discrim-ination,a limit of gain amplitude is proposed for future measuring nuclear recoil in the MIMAC detector.Based on the obtained detector performance parameters,using the binned Poisson statistical method,predictions of the spin-independent and spin-dependent sensitivity curves that can be achieved in future MIMAC detection experiments are given.This work allows to set conditions for the use of a large TPC in the future underground detections to confirm the Galactic origin of Dark Matter signals and the direct detection beyond the neutrino floor.