Collaborative Research: R&D Towards Higher Sensitivity Directional Dark Matter Detectors

在这个精确宇宙学的时代，测量表明，普通物质只占宇宙总物质密度的一小部分。其余的，我们只能通过引力推断其存在，其本质是未知的，被称为暗物质。粒子物理学认为暗物质由大爆炸遗留下来的弱相互作用大质量粒子（wimp）组成。由于相互作用概率小，背景大，直接探测wimp的实验工作极具挑战性。地球在星系中的运动产生了大质量弱相互作用粒子的逆风。WIMP相互作用的反冲角分布具有~100%的不对称性，并且由于地球的自转而以恒星速率调制。没有任何已知的背景可以模拟这个信号。为这种搜索而开发的技术的实际含义在低背景α和中子测量方面有很好的应用前景。这项工作还包括在越来越罕见的小规模实验中训练各种各样的本科生和研究生，使他们接触到广泛的研究经验。轨道定向后坐力识别（DRIFT）实验在定向暗物质探测领域处于领先地位。该奖项的学术价值在于DRIFT对这种调制信号的敏感性，这为当今科学中最重要的问题之一提供了一个独特的窗口。在过去的几年里，由nsf资助的DRIFT-IId项目取得了巨大的实验进展。该合作正处于调试新的DRIFT-IIe探测器的最后阶段。两个探测器的运行将测试长时间无背景照射的可行性。该奖项将为继续开展第二期漂流项目提供资金。

In this era of precision cosmology, measurements suggest that ordinary matter represents only a fraction of the total matter density in the Universe. The rest, whose presence we only infer gravitationally, is unknown in its nature, and is termed dark matter. Particle physics suggests that dark matter comprises relic Weakly Interacting Massive Particles (WIMPs) left over from the Big Bang. Experimental efforts to directly detect WIMPs are extremely challenging due to small interaction probabilities and large backgrounds. The motion of the Earth through the galaxy produces a head-wind of WIMPs. The angular distribution of recoils from WIMP interactions has a ~100% asymmetry, and is modulated at the sidereal rate on account of the Earth's rotation. No known background can mimic this signal. The practical implications of the technology being developed for such searches have promising applications to low background alpha and neutron measurements. This work also includes the training of a diverse set of undergraduates and graduate students in increasingly rare small-scale experiments, giving them exposure to a wide range of research experience.The Directional Recoil Identification From Tracks (DRIFT) experiment leads the field of directional dark matter detection. The intellectual merit of this award resides in DRIFT's sensitivity to this modulated signature, which provides a unique window into one of the most important questions in science today. NSF-funded DRIFT-IId work over the last several years has led to enormous experimental progress. The collaboration is in the final stages of commissioning a new DRIFT-IIe detector. The operation of both detectors will test the viability of long-duration background-free exposures. This award will provide funding to continue the operations of DRIFT-II.