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.**

氦和铅天文台(HALO)是一种低成本、长寿命、低维护的超新星探测器，自2012年5月开始在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，与世界上其他探测器相辅相成。光晕是超新星预警系统的成员之一。需要为光晕的持续运行和维护提供支持。第二类超新星是由大质量恒星核心的引力坍塌提供动力的。这颗炽热的原中子星主要通过发射各种类型的中微子在几十秒内冷却。释放出来的引力势能约有99%以~10 MeV中微子的形式出现。从概念上讲，Halo是用He-3中子探测器测量的80吨铅。来自超新星的中微子通过带电电流(CC)和中性电流的弱相互作用激发铅原子核，从而使一个或两个中子被抛出。在Halo的He-3探测器中检测到这些中子，是银河系超新星的信号。光度、光谱和平均中微子能量的时间演化为了解超新星动力学提供了一个直接窗口。铅的中子过量提供了对νe通量的CC相互作用的主要敏感性。超新星模型结合观测数据，提供了提取中微子基本性质的可能性，并促进了我们对超新星机制的理解。SNOLAB的光晕大小适中，受到统计数据的限制，超新星距离越远，或中微子能量越低，这种情况就越严重。意大利LNGS的OPERA探测器退役后，1.3kT的铅可用于建造新的探测器Halo-1kT，其灵敏度最高可达Halo的30倍。此外，美国能源部新提供的He-3为建造更多的He-3中子计数器开辟了一条道路。要求为撰写技术设计报告所需的研究提供原则性测量的支持。*我们还希望加入一致的合作，首次测量与超新星相关的能量下的中微子-铅截面。橡树岭国家实验室的散裂中子源(SNS)从静止的介子和介子衰变中产生强烈的中微子脉冲。现有的Halo开发数据采集系统，加上备用的He-3中子探测器，将使我们能够很容易地测量中微子-铅截面。需要支持将此硬件传输到SNS或从SNS传出。这项测量将完成对Halo的校准，并有助于确定Halo-1kT的能力。现有的和计划中的中微子探测器只对我们银河系内发生的超新星敏感。预计每个世纪只有2-3个，所以用许多不同特性和灵敏度的探测器观察下一个很重要。从SN 1987A的20个事件中学到了很多东西。下一颗银河系超新星应该会有更多的可能性。**