Collaborative Research: DRIFT-III: Engineering for A Large Directional Dark Matter Detector

在这个精确宇宙学的时代，测量表明，普通物质（质子和中子）只代表宇宙中总物质密度的一小部分。其余的，我们只能看到引力的影响，其性质是未知的，被称为暗物质。粒子物理学模型表明，暗物质是由大爆炸后遗留下来的弱相互作用大质量粒子（WIMP）组成的。直接检测WIMP的实验努力是具有挑战性的，因为预测的相互作用概率很小，并且存在模拟预期信号的大背景。然而，存在许多独特的暗物质特征，可以用来区分背景并决定性地识别WIMP相互作用。最大和最强大的签名是预测的依赖于太阳-地球的速度通过星系的WIMP通量，产生昼夜调制的核反冲方向在实验室中。在目前使用方向探测器的搜索中，来自轨道的方向反冲识别（DRIFT）实验是一个领导者，拥有十年的经验。这个建议的智力价值在于DRIFT的独特和强大的能力，被带到承担当今科学中最重要的问题之一。背景抑制方面的这些进展，加上DRIFT-II体积小妨碍了进一步的极限设置能力，表明DRIFT应该扩大规模。该合同将使双方能够继续在英格兰的Boulby矿山运行DRIFT-II。除了运行DRIFT-IId外，这些资金还将为第二个探测器DRIFT-IIe提供硬件。这项工作的更广泛影响包括在越来越罕见的小规模实验中培训各种本科生和研究生（包括代表性不足的少数民族），让他们接触到广泛的硬件和软件经验。最后，DRIFT探测器技术在国土安全和双β衰变实验中有很好的应用前景。

In this era of precision cosmology, measurements suggest that ordinary matter (protons and neutrons) represents only a fraction of the total matter density in the Universe. The rest, whose effect we can see only gravitationally, is unknown in its nature and is termed Dark Matter. Particle physics models suggest that dark matter is composed of relic Weakly Interacting Massive Particles (WIMPs) left over from the Big Bang. Experimental efforts to directly detect WIMPs are challenging due to the predicted small interaction probabilities and the existence of large backgrounds that mimic the expected signal. However, a number of unique dark matter signatures exist that can be used to discriminate against backgrounds and decisively identify WIMP interactions. The largest and most robust signature is the predicted dependence of the WIMP flux on the Sun-Earth velocity through the galaxy, yielding a day-night modulation of the nuclear recoil direction in the laboratory. Of current searches with directional detectors, the Directional Recoil Identification From Tracks (DRIFT) experiment is a leader, having a decade of experience. The intellectual merit of this proposal resides in DRIFT's unique and powerful capabilities being brought to bear on one of the most important questions in science today. These advances in background rejection, combined with the fact that further limit setting capabilities are hampered by the small volume of DRIFT-II, suggest that DRIFT should scale-up. This award will enable the collaboration to continue running DRIFT-II in the Boulby mine in England. In addition to running DRIFT-IId, these funds will provide hardware for a second detector, DRIFT-IIe.Broader impacts of this work include the training of a diverse set of undergraduates and graduate students (including underrepresented minorities) in increasingly rare small-scale experiments, giving them exposure to a wide range of hardware and software experience. Finally, the DRIFT detector technology has promising applications to Homeland Security and double-beta decay experiments.