MiMac is a project of micro-TPC matrix of gaseous (He3, CF4) chambers for direct detection of non-baryonic dark matter. Measurement of both track and ionization energy will allow the electron-recoil discrimination, while access to the directionnality of the tracks will open a unique way to distinguish a geniune WIMP signal from any background. First reconstructed tracks of 5.9 keV electrons are presented as a proof of concept.
Directional detection of Dark Matter with the MIcro-tpc MAtrix of Chambers
与普通物质弱相互作用的粒子，其相关质量为原子核（WIMPs）量级，是暗物质的可能候选者。由这些WIMP之一引起的靶核的弹性碰撞的直接检测必须与由中子产生的信号区分开，中子产生的信号在检测器中留下相同的信号。MIMAC（MIcro-tpc MAGNETIC of Chambers）合作开发了一种原始的原型探测器，该探测器将大型像素化Micromegas与快速自触发电子器件相结合。介绍了Modane地下实验室中运行的双室模块的各个方面：$^{222}$ Rn子体的校准和表征。建立了一个新的实验台，它结合了MIMAC室和COMIMAC便携式淬火线，用于表征MIMAC混合气体中低能离子的三维径迹：给出了初步结果。简要讨论了今后的步骤。
Weakly Interacting Massive Particles (WIMPs) are one of the most preferred candidate for Dark Matter. WIMPs should interact with the nuclei of detectors. If a robust signal is eventually observed in direct detection experiments, the best signature to confirm its Galactic origin would be the nuclear recoil track direction. The MIMAC collaboration has developed a low pressure gas detector providing both the kinetic energy and three-dimensional track reconstruction of nuclear recoils. In this paper we report the first ever observations of $^{19}$F nuclei tracks in a $5$ cm drift prototype MIMAC d…
MIMAC low energy electron-recoil discrimination measured with fast neutrons
MIMAC（MIcro-TPC MATERIAL of Chambers）是一个定向WIMP暗物质探测器项目。直接的暗物质实验需要高水平的电子/反冲鉴别来寻找由WIMP-核弹性散射产生的核反冲。在本文中，我们提出了一个原始的方法，电子事件拒绝的基础上，应用于实验数据采集单色中子场的多元分析。该分析表明，$10^5$抑制功率对于电子/反冲辨别是可达到的。此外，通过蒙特卡罗模拟估计效率，表明在考虑全能量范围的情况下，利用$86.49\pm 0.17$ \%的核反冲效率达到105电子排斥功率，并且在考虑5 keV的低阈值的情况下，利用$94.67\pm0.19$ \%的核反冲效率达到105电子排斥功率。
Dark matter detectors with directional sensitivity have the capability to distinguish dark matter induced nuclear recoils from isotropic backgrounds, thus providing a smoking gun signature for dark matter in the Galactic halo. Motivated by recent progress in graphene and two-dimensional materials research, we propose a novel class of directional dark matter detectors utilizing graphene-based van der Waals heterostructures. A conceptual design of the detector based on graphene/hexagonal boron nitride and graphene/molybdenum disulfide heterostructures is developed and analyzed. The proposed dete…
Nuclear emulsion is a well-known detector type proposed also for the directional detection of dark matter. In this paper, we study one of the most important properties of direction-sensitive detectors: the preservation by nuclear recoils of the direction of impinging dark matter particles. For nuclear emulsion detectors, it is the first detailed study where a realistic nuclear recoil energy distribution with all possible recoil atom types is exploited. Moreover, for the first time we study the granularity effect on the emulsion detector directional performance. As well as we compare nuclear em…
We provide an algorithm for detection of possible dark matter particle interactions recorded within NEWSdm detector. The NEWSdm (Nuclear Emulsions for WIMP Search directional measure) is an underground Direct detection Dark Matter search experiment. The usage of recent developments in the nuclear emulsions allows probing new regions in the WIMP parameter space. The directional approach, which is the key feature of the NEWSdm experiment, gives the unique chance of overcoming the "neutrino floor". Deep Neural Networks were used for separation between potential DM signal and various classes of ba…
We demonstrate a new type of analysis for the DRIFT-IId directional dark matter detector using a machine learning algorithm called a Random Forest Classifier. The analysis labels events as signal or background based on a series of selection parameters, rather than solely applying hard cuts. The analysis efficiency is shown to be comparable to our previous result at high energy but with increased efficiency at lower energies. This leads to a projected sensitivity enhancement of one order of magnitude below a WIMP mass of 15 GeV c$^{-2}$ and a projected sensitivity limit that reaches down to a W…
The quasiparticle propagation away from the track of a highly ionizing particle in superfluid helium at low temperatures has previously been shown to exhibit anisotropy. We discuss the mechanism responsible for this behavior and show that it occurs for nuclear scattering by dark matter for recoil energies down to a few keV, and perhaps lower. This makes it possible to extend WIMP searches with interaction cross sections that reach into the neutrino floor in a meaningful energy range.
Light dark matter in the context of dark sector theories is an attractive candidate for the dark matter thought to make up the bulk of the mass of our universe. We explore here the possibility of using a low-pressure, negative-ion, time projection chamber detector to search for light dark matter behind the beam dump of an electron accelerator. The sensitivity of a 10 m long detector is several orders of magnitude better than existing limits. This sensitivity includes regions of parameter space where light dark matter is predicted to have a required relic density consistent with measured dark m…
A negative ion micro time projection chamber (NI$μ$TPC) was developed and its performance studied. An NI$μ$TPC is a novel technology that enables the measurement of absolute $z$ coordinates for self-triggering TPCs. This technology provides full-fiducialization analysis, which is not possible with conventional gaseous TPCs, and is useful for directional dark matter searches in terms of background rejection and the improvement of the angular resolution. The developed NI$μ$TPC prototype had a detection volume of 12.8 $\times$ 25.6 $\times$ 144 mm$^{3}$. The absolute $z$ coordinate was determined…
Sensitivities of current directional dark matter search detectors using gas time projection chambers are now constrained by target mass. A ton-scale gas TPC detector will require large charge readout areas. We present a first demonstration of a novel ThGEM-Multiwire hybrid charge readout technology which combines the robust nature and high gas gain of Thick Gaseous Electron Multipliers with lower capacitive noise of a one-plane multiwire charge readout in SF$_6$ target gas. Measurements performed with this hybrid detector show an ion drift velocity of $139~\pm~12~\text{ms}^{-1}$ in a reduced d…
