HALO at SNOLAB

SNOLAB 的光环

• 批准号: 355451-2012
• 负责人: Virtue, Clarence
• 金额: $ 4.74万
• 依托单位: Laurentian University of Sudbury
• 依托单位国家: 加拿大
• 项目类别: Subatomic Physics Envelope - Project
• 财政年份: 2012
• 资助国家: 加拿大
• 起止时间: 2012-01-01 至 2013-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=515183
• 关键词: HALO; SNOLAB

The Helium and Lead Observatory (HALO) is a supernova neutrino detector currently under construction at SNOLAB. HALO is a long term, low cost, high livetime, and low maintenance, dedicated supernova detector. A core-collapse supernova is powered by the energy liberated in the gravitational collapse of the core of a massive star. The core is transformed to a hot proto-neutron star that rapidly cools by the emission of neutrinos of all flavours. In fact, about 99% of the total energy is released in the form of ~ 10 MeV neutrinos, in some tens of seconds. The direct measurement of the time evolution of the luminosity, flavour partition, and average neutrino energies are our best experimental window into the challenging field of supernova dynamics which is expected to lead to an improved understanding of supernovae and of fundamental neutrino properties. Lead is particularly interesting, as a medium for supernova detection, due to its low cost, high neutrino cross-section and low neutron absorption cross-section. Neutrino interactions in lead expel neutrons from the lead nuclei making a burst of detected neutrons the signature for the detection of a supernova. Conceptually HALO is a volume of lead instrumented with neutron detectors and shielded from environmental neutrons by water. While other supernova detectors are primarily sensitive to electron antineutrinos the nuclear physics of lead makes HALO dominantly sensitive to electron neutrinos through the charged current interaction and to all flavours of neutrinos through the neutral current interaction. These complementary sensitivities ensure that supernova data from HALO will be vital to unravelling the supernova neutrino signal and extracting physics from the next galactic supernova. The public investment required for the construction of HALO was kept modest by having access to 79 tonnes of lead, from the decommissioned Deep River Cosmic Ray Station, and more than 600 meters of He-3 neutron detectors from the final phase of the SNO experiment. These assets, valued at approximately seven million dollars, have been employed in the construction of HALO in SNOLAB.

氦铅天文台 (HALO) 是一个超新星中微子探测器，目前正在 SNOLAB 建设中。 HALO 是一种长期、低成本、高寿命、低维护的专用超新星探测器。核心塌缩超新星由大质量恒星核心引力塌缩释放的能量提供动力。核心转变为炽热的原中子星，并通过发射各种中微子而迅速冷却。事实上，大约 99% 的总能量在几十秒内以约 10 MeV 中微子的形式释放。直接测量光度、味道分配和平均中微子能量的时间演化是我们进入超新星动力学这一具有挑战性领域的最佳实验窗口，预计这将有助于加深对超新星和中微子基本特性的理解。铅作为超新星探测介质特别有趣，因为它成本低、中微子截面高、中子吸收截面低。铅中的中微子相互作用将中子从铅核中排出，使得检测到的中子爆发成为检测超新星的特征。从概念上讲，HALO 是装有中子探测器的铅体积，并通过水屏蔽环境中子。虽然其他超新星探测器主要对电子反中微子敏感，但铅的核物理特性使得 HALO 主要通过带电电流相互作用对电子中微子敏感，并通过中性电流相互作用对所有类型的中微子敏感。这些互补的敏感性确保来自 HALO 的超新星数据对于解开超新星中微子信号并从下一个银河系超新星中提取物理学至关重要。建造 HALO 所需的公共投资保持适度，因为它使用了来自退役的深河宇宙射线站的 79 吨铅，以及来自 SNO 实验最后阶段的 600 多米的 He-3 中子探测器。这些资产价值约七百万美元，已用于 SNOLAB 的 HALO 建设。