Collaborative Research: A Depleted Argon Detector for a Dark Matter Search

暗物质的存在是通过引力效应得知的，但它的性质仍然是一个深层次的谜团。在基本粒子物理学其他考虑因素的推动下，一种可能性是暗物质由未被发现的基本粒子组成。轴子和弱相互作用大质量粒子(WIMP)是两种可能性。由环绕银河系和地球的暗物质晕组成的WIMPS的热运动应该会导致WIMP与核的碰撞，能量足够高，可以用敏感的实验室设备观察到。该奖项是为了开发和部署一种小型液体Ar探测器，它具有高灵敏度，可以直接探测WIMP碰撞。这种名为Darkside-50的探测器建立在过去经验的基础上，并引入了创新的功能，使其能够在无背景模式下运行，从而实现重大的科学结果，尽管其体积相对较小。同时，该探测器将作为未来多吨探测器的原型。正在推出的主要创新：-在放射性39Ar中耗尽的地下Ar；-低本底、高量子效率的Qupid光电探测器；以及-紧凑、高效的外部对中子的否决权。这些创新与Ar强大的双参数背景抑制特性将导致一种具有前所未有的无背景性能的探测器。Darkside-50将要么探测WIMP暗物质，要么排除大部分受青睐的参数空间。Darkside-50将受益于枯竭的Ar的提取和提炼设施，该设施由美国国家科学基金会通过向普林斯顿大学提供赠款而独立提供资金。更广泛的影响：这项活动将以各种方式推动天体粒子物理学的发展及其科学和教育使命：(1)它将提供一个极好的培训学生的机会，他们将有机会为基础科学和先进工程领域的尖端项目的成功做出贡献；(2)它将通过开发可应用于从国家安全到医学成像等领域的技术来造福社会；(3)它将支持继续发展成功的E&amp；O项目，如为高中生开设的普林斯顿-阿布鲁佐-南达科他州暑期学校。

The existence of dark matter is known from gravitational effects, but its nature remains a deep mystery. One possibility motivated by other considerations in elementary particle physics is that dark matter consists of undiscovered elementary particles. Axions and Weakly Interacting Massive Particles (WIMPs) are two possibilities. The thermal motion of the WIMPS comprising the dark matter halo surrounding the galaxy and the earth should result in WIMP-nuclear collisions of sufficient energy to be observable by sensitive laboratory apparatus.This award is to develop and deploy a small liquid argon detector that has high sensitivity for direct detection of WIMP collisions. This detector, DarkSide-50, builds on past experience and introduces innovative features that will allow it to operate in a background-free mode and thereby achieve a significant science result in spite of its relatively small size. At the same time, this detector will serve as a prototype for a future multi-ton detector. The main innovations being introduced:- Underground argon depleted in radioactive 39Ar;- Low background, high-quantum-efficiency QUPID photo-detectors; and- A compact high-efficiency external veto for neutrons.These innovations, together with the powerful two-parameter background rejection features of argon will result in a detector of unprecedented background-free performance. DarkSide-50 will either detect WIMP dark matter or exclude a substantial fraction of the favored parameter space. DarkSide-50 will benefit from the facility for extraction and refinement of depleted argon, independently funded by the NSF through a grant to Princeton University. Broader Impacts: this activity will advance the development of astroparticle physics and its scientific and educational mission in a variety of ways: (1) it will offer an excellent opportunity for the training of students, who will have a chance to contribute to the success of a cutting edge project in fundamental science and advanced engineering; (2) it will benefit society by developing techniques that could find application in areas ranging from national security to medical imaging; (3) it will support continued development of successful E&O programs such as the Princeton-Abruzzo-South Dakota summer school for high school students.