Collaborative Research: Developing new readout methods for dark matter detectors with directional sensitivity

过去十年的宇宙学测量表明，宇宙中23%的物质是暗物质。暗物质最受青睐的候选者是与中子和质子相互作用很弱的大质量粒子。通过测量暗物质粒子在弹性碰撞中转移到原子核的总能量，几个实验正在进行中，以探测暗物质。该计划是建造一个探测器，测量反冲核的方向和能量。由于地球通过暗物质的静态光环运行，确定暗物质到达的表观方向的能力使该计划相对于简单地测量核反冲能量的实验具有决定性的优势。提出了两种方法。在一种方案中(使用CF4气体)，反冲的图像是通过使用CCD相机对放大过程中发射的光子成像来确定的。麻省理工学院-伯克利分校的团队已经在一个0.05L的探测器上展示了这种方法，现在的建议是建造一个250%的L探测器，能够进行科学竞争的测量。CF4的使用也为该方案提供了独特的途径，可以了解暗物质与中子和质子之间的自旋相关相互作用。在第二种方案中(使用CS2气体)，在放大系统的导线上收集的电荷决定了反冲的方向。在Boulby矿运营探测器的漂移合作公司已经证明了这种方法，建议对漂移探测器的电子设备进行重大改进，使其在科学上具有竞争力。这两种方法相辅相成，寻找自旋相关(CF4)和自旋无关(CS2)相互作用。在更广泛的影响领域，尽管提议的是暗物质探测器，但相同的系统可以用于探测低能中子，可能对射线照相、反应堆安全或货物检查有价值。其中一个关键部件是大型电荷耦合器件(CCD)相机和光学系统。

Cosmological measurements over the past ten years indicate that 23% of the matter in theUniverse is dark matter. The favored candidates for dark matter are massive particles which weakly interact with neutrons and protons. Several experiments are underway to detect dark matter by measuring the total energy a dark matter particle transfers to a nucleus in an elastic collision. The proposal is to build a detector that will measure both the direction and energy of the recoiling nucleus. Since the earth moves through a static halo of dark matter, the ability to determine the apparent direction from which the dark matter arrives gives this scheme a decisive advantage over experiments which simply measure the nuclear recoil energy. Two approaches are proposed. In one scheme (using CF4 gas), the image of the recoil is determined by imaging the photons emitted in the amplification process using a CCD camera. The MIT-BU group has demonstrated this method in a 0.05 liter detector and the proposal is to now construct a 250 l detector capable of making a scientifically competitive measurement. The use of CF4 also gives this scheme unique access to spin dependent interactions between dark matter and neutrons and protons. In the second scheme (using CS2 gas), charges collected on the wires of the amplification system determine the direction of the recoil. This method has been demonstrated by the DRIFT collaboration, which operates detectors in the Boulby Mine, and the proposal is to make a major improvement of the electronics in the DRIFT detectors to make them scientifically competitive. The two approaches complement each other by searching for spin-dependent (CF4) and spin-independent (CS2) interactions.In the area of Broader Impacts, although the proposal is for a dark matter detector, the same system could be used for detection of low energy neutrons and may be valuable for radiography, reactor safety or cargo screening. A key element is the large charge coupled device (CCD) camera and optical system.