EAGER: Research and Development of Dark Matter Detectors for Borexino

该奖项旨在奖励一项探索性的、高风险的、高回报的努力，以开发一种新的暗物质探测仪器。观测表明，宇宙中80%的物质不是由普通原子组成的，而是由未被探测到的基本暗物质粒子组成的，它们既不发射光，也不吸收光。关于暗物质本质的主要假设是，它由大爆炸后瞬间产生的新基本粒子组成，通常被称为弱相互作用大质量粒子。在地球实验中探测它们的一种方法是测量它们在与正常物质的罕见相互作用中产生的低能核反冲。该小组将开发小型NaI和液态氙探测器，可安装在意大利格兰萨索地下实验室的太阳中微子Borexino探测器中，用于暗物质搜索。探测器将通过现有的管道插入Borexino液体闪烁体的中心。当定位在Borexino闪烁体时，由于外部伽玛射线和中子源，小型探测器中的背景可以忽略不计。Borexino闪烁体也可以作为一个非常有效的反巧合探测器来否决内部的伽马和中子背景，这些背景起源于并散射在小型探测器和Borexino闪烁体中。一个10公斤的探测器，结合来自外部和内部源的低背景，应该有足够的灵敏度来测试所报告的DAMA/LIBRA暗物质信号的有效性。对于更广泛的影响，这个提议解决了我们这个时代的一个主要科学问题，宇宙中暗物质的本质。作为一个交叉学科，它也对先进的探测器技术产生影响。PI承诺让本科生参与他的研究项目。

This EAGER award is for an exploratory, high-risk, high-payoff effort to develop a novel instrument for dark matter detection. Observations indicate that 80% of the matter in the Universe is not made of normal atoms, but must be otherwise undetected elementary Dark Matter particles that do not emit or absorb light. The leading hypothesis for the nature of dark matter is that it consists of new elementary particles produced moments after the Big Bang, generally referred to as Weakly Interacting Massive Particles. One way to detect them in an Earth-bound experiment is to measure the low energy nuclear recoils they produce in rare interactions with normal matter. This group will develop small NaI and liquid xenon detectors that can be installed in the Solar Neutrino Borexino detector, at the Gran Sasso Underground Laboratory, Italy, for a dark matter search. The detector would be inserted through existing plumbing tubes into the center of the Borexino liquid scintillator. When positioned in the Borexino scintillator, the background in the small detector due to external sources of gamma rays and neutrons will be negligible. The Borexino scintillator also serves as a very efficient anti-coincidence detector to veto internal gamma and neutron backgrounds that originate and scatter within the small detector and in the Borexino scintillator. A 10-kg detector with the combination of low backgrounds from external and internal sources should have sufficient sensitivity to test the validity of the reported DAMA/LIBRA dark matter signal. For Broader Impacts, this proposal addresses one of the major scientific questions of our time, the nature of dark matter in the universe. As a cross-disciplinary topic it also has an impact on advanced detector technology. The PI has a commitment to involving undergraduates in his research projects.