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）只占宇宙中总物质密度的一小部分。其余的物质，其作用我们只能在引力作用下看到，其性质是未知的，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弱相互作用大质量粒子（wimp）组成的。直接探测wimp的实验工作是具有挑战性的，因为预测的相互作用概率很小，而且存在模仿预期信号的大背景。然而，存在一些独特的暗物质特征，可以用来区分背景，并果断地识别WIMP相互作用。最大和最强大的特征是预测WIMP通量与穿过星系的太阳-地球速度的依赖关系，在实验室中产生了昼夜调制的核反冲方向。在目前使用定向探测器的搜索中，轨道定向后坐力识别（DRIFT）实验是一个领导者，有十年的经验。这项提议的智力价值在于，DRIFT独特而强大的能力被用于解决当今科学中最重要的问题之一。这些背景抑制方面的进展，再加上DRIFT- ii体积小阻碍了进一步设限的能力，表明DRIFT应该扩大规模。该奖项将使合作能够继续在英国Boulby矿运行DRIFT-II。除了运行DRIFT-IId之外，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各样的本科生和研究生（包括代表性不足的少数民族），使他们接触到广泛的硬件和软件体验。最后，漂移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.