Neutron Detector R&D for HALO-1kT TDR

中子探测器 R

• 批准号: SAPPJ-2017-00041
• 负责人: Virtue, Clarence
• 金额: $ 2.91万
• 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: 2018
• 资助国家: 加拿大
• 起止时间: 2018-01-01 至 2019-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=667833
• 关键词: Neutron; Detector; R&D; HALO; 1kT

The Helium and Lead Observatory (HALO) is a low cost, high livetime, low maintenance supernova detector running at SNOLAB since May 2012. The use of lead as the target material gives HALO unique sensitivity to electron neutrinos, complementary to other detectors worldwide. HALO is a member of the SuperNova Early Warning System. Support is requested for the ongoing operation and maintenance of HALO.******A type II supernova is powered by the gravitational collapse of the core of a massive star. The hot proto-neutron star cools primarily by the emission of neutrinos, of all flavours, in some tens of seconds. About 99% of the gravitational potential energy liberated emerges as ~10MeV neutrinos. Conceptually, HALO is 80 tonnes of lead instrumented with He-3 neutron detectors. Neutrinos from the supernova excite lead nuclei via both charged current (CC) and neutral current weak interactions to states from which one or two neutrons are ejected. The detection of these neutrons in HALO's He-3 detectors signals a galactic supernova. The time evolution of the luminosity, flavours and average neutrino energy give a direct window into supernova dynamics. The neutron excess of lead provides for a dominant sensitivity to CC interactions of the νe flux. Modeling of supernovae combined with observational data, offers the possibility of extracting fundamental neutrino properties as well as advancing our understanding of the supernova mechanism. HALO at SNOLAB is modest in size and limited by statistics, more so the further the supernova, or the lower the neutrino energy. The decommissioning of the OPERA detector at LNGS in Italy makes 1.3 kT of lead available for the construction of a new detector, HALO-1kT, up to 30 times more sensitive than HALO. Also the new availability of He-3 from the US DOE opens a path to build more He-3 neutron counters. Support is requested for proof of principle measurements for the studies necessary to write a Technical Design Report.******We also wish to join the COHERENT Collaboration to make the first measurement of neutrino-lead cross sections at supernova-relevant energies. The Spallation Neutron Source (SNS) at Oak Ridge National Laboratory produces intense pulses of neutrinos from pion and muon decay at rest. The existing HALO development data acquisition system, together with spare He-3 neutron detectors would enable us to easily measure the neutrino-lead cross section. Support is requested to transport this hardware to and from the SNS. This measurement would complete the calibration of HALO as well as help define the capabilities of HALO-1kT.******Existing and planned neutrino detectors are only sensitive to supernovae occurring within our Galaxy. Only 2-3 are expected per century, so it is important to observe the next one with many detectors of diverse characteristics and sensitivities. Much was learnt from the 20 events from SN 1987A. Much more should be possible from the next galactic supernova.**

氦铅天文台 (HALO) 是一款低成本、长寿命、低维护的超新星探测器，自 2012 年 5 月起在 SNOLAB 运行。使用铅作为目标材料使 HALO 对电子中微子具有独特的灵敏度，与全球其他探测器相辅相成。是超新星早期预警系统的成员，需要为 HALO 的持续运行和维护提供支持。******II 型超新星由引力塌缩提供动力。一颗大质量恒星的核心主要通过发射各种中微子而冷却，在大约几十秒内释放出约 99% 的引力势能。从概念上讲，HALO 是中微子。 80 吨铅配备了 He-3 中子探测器，来自超新星的中微子通过带电电流 (CC) 和中性电流激发铅核。 HALO 的 He-3 探测器对这些中子的弱相互作用发出了星系超新星的信号，光度、味道和平均中微子能量的时间演化为了解超新星中子动力学提供了一个直接的窗口。过量的铅对 νe 通量的 CC 相互作用具有显着的敏感性 超新星建模与观测数据相结合，提供了提取基本中微子特性的可能性。 SNOLAB 的 HALO 规模较小，且受到统计数据的限制，超新星距离越远，或中微子能量越低，意大利 LNGS 的 OPERA 探测器退役后为 1.3 kT。铅可用于构建新探测器 HALO-1kT，其灵敏度比 HALO 高出 30 倍。此外，美国能源部推出的新 He-3 也开启了新的探测器。建立更多 He-3 中子计数器的途径。请求支持编写技术设计报告所需的研究的原理测量证明。******我们还希望加入 COHERENT 合作来首次测量中微子。橡树岭国家实验室的散裂中子源（SNS）在静止状态下产生来自π介子和μ介子衰变的强烈中微子脉冲，以及备用的HALO开发数据采集系统。 He-3 中子探测器将使我们能够轻松测量中微子引线横截面，需要支持将该硬件往返于 SNS。这种测量将完成 HALO 的校准并帮助定义 HALO-1kT 的功能。 .*****现有和计划中的中微子探测器仅对银河系内发生的超新星敏感，预计每个世纪只会出现 2-3 个中微子探测器，因此观察下一个具有不同特征和特性的探测器非常重要。从 SN 1987A 的 20 个事件中我们可以学到很多东西。**