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

在这个精密宇宙学的时代，测量表明普通物质(质子和中子)只占宇宙总物质密度的一小部分。其余的，我们只能通过引力才能看到它的影响，它的性质是未知的，被称为暗物质。粒子物理模型表明，暗物质是由大爆炸遗留下来的残余弱相互作用大质量粒子(WIMP)组成的。直接探测WIMP的实验工作具有挑战性，因为预测的相互作用概率很小，而且存在模拟预期信号的大背景。然而，存在一些独特的暗物质信号，可以用来区分背景并决定性地识别WIMP相互作用。最大和最强大的特征是预测的WIMP通量对穿过银河系的太阳-地球速度的依赖，产生了实验室中核反冲方向的昼夜调制。在目前使用定向探测器进行的搜索中，航迹的定向反冲识别(漂移)实验是领先的，拥有十年的经验。这一提议的智力价值在于，漂移的独特和强大的能力被用于解决当今科学中最重要的问题之一。背景抑制方面的这些进展，再加上漂移-II的小体积阻碍了进一步的限制设置能力的事实，表明漂移应该扩大。这项合同将使合作伙伴能够继续在英格兰的博尔比矿运行漂移-II。除了运行DRIFE-IID之外，这些基金还将为第二个探测器DEVER-II提供硬件。这项工作的广泛影响包括在越来越罕见的小规模实验中培训一批不同的本科生和研究生(包括代表不足的少数族裔)，让他们接触到广泛的硬件和软件经验。最后，漂移探测器技术在国土安全和双贝塔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.