Particle Astrophysics with Neutrinos and Weakly Interacting Dark Matter: Borexino and DarkSide

该奖项为马萨诸塞大学阿姆赫斯特分校的粒子天体物理学项目提供了基础支持，该项目参与了Borexino太阳中微子实验和寻找银河系中弱相互作用粒子暗物质（wimp）的DarkSide项目。太阳中微子在实验证实中微子具有质量和振荡方面发挥了至关重要的作用。自2007年开始数据采集以来，Borexino已经达到了设计目标，并以足够的精度测量了单能7-铍太阳中微子的通量，以测试当前太阳模型的预测。在2011年的闪烁体净化运动之后，Borexino进入了太阳中微子物理学的新阶段，目标是测量整个太阳中微子光谱。对太阳中微子的精确了解将使我们能够了解太阳和其他恒星的工作方式，测试MSW-LMA中微子振荡范式，并寻找偏离它的地方。Borexino可能会解决一个悬而未决的问题，即太阳核心的金属丰度，这是研究宇宙中较大恒星演化的重要信息。DarkSide-50是一个双相位时间投影室，计划于2012年底投入使用，它将设计出无背景的多吨探测器的原型解决方案，该探测器以液态氩作为wimp的主动目标。一次无效的观测将会排除一些目前主要的暗物质候选者。一个积极的发现将开始为我们这个时代的一个重大科学未知数提供答案。DarkSide-50将在放射性同位素39-Argon中消耗超过100倍的50公斤氩。DarkSide-50氩低温恒温器由一个紧凑的液体闪烁中子探测器包围，并浸入Borexino计数测试设施（CTF）水箱中，作为切伦科夫μ子否决权运行。Borexino和DarkSide的合作在人员、技术和运营资源方面有很大的重叠。更广泛的影响：Borexino和DarkSide项目为研究生和本科生在软件和硬件开发应用以及基础物理方面的培训提供了极好的机会。为Borexino和Darkside-50开发的技术可以更广泛地有益于与医学成像、核不扩散和地质学相关的技术。

This award provides base support for the particle astrophysics program at the University of Massachusetts, Amherst to participate in the Borexino solar neutrino experiment and the DarkSide project for the search of weakly interacting particle dark matter (WIMPs) in our galaxy. Solar neutrinos have played a crucial role in the experimental confirmation that neutrinos have mass and oscillate. Since data acquisition started in 2007, Borexino has reached its design goal and measured the flux of mono-energetic 7-Beryllium solar neutrinos with enough precision to test the predictions of current solar models. After a scintillator purification campaign in 2011, Borexino is in a new phase of solar neutrino physics with the goal of measuring the entire solar neutrino spectrum. A precise knowledge of solar neutrinos will allow us to understand how the sun and other stars work, test the MSW-LMA neutrino oscillation paradigm and search for deviations from it. Borexino will possibly resolve an open question on the metallicity of the Sun's core, an important piece of information with which to study the evolution of larger stars in the universe. DarkSide-50, a dual-phase time projection chamber scheduled to come online in late 2012, will prototype design solutions for background free multi-tonne detectors with liquid argon as active target for WIMPs. A null observation would exclude some of the current leading dark matter candidates. A positive detection would begin to give answers to one of the big scientific unknowns of our times. DarkSide-50 will run with 50 kg of argon depleted more than 100-fold in the radioactive 39-Argon isotope. The DarkSide-50 Argon cryostat is surrounded by a compact, liquid scintillator neutron detector and immersed in the Borexino Counting Test Facility (CTF) water tank instrumented and operated as a Cherenkov muon veto. The Borexino and DarkSide collaborations have a significant overlap in personnel and technical and operational resources. Broader Impacts: The Borexino and DarkSide projects provide excellent opportunities for the training of graduate and undergraduate students in applications of software and hardware development, and fundamental physics. The techniques developed for Borexino and Darkside-50 can more broadly benefit technology relevant for medical imaging, nuclear non-proliferation and geology.