HALO-1kT at LNGS

第二类超新星是由大质量恒星核心引力坍缩释放的能量提供动力的。在核心坍塌后，最初非常热的原中子星主要通过发射大致平均分配的各种中微子来冷却。事实上，大约99%的初始引力势能是在几十秒内通过~10 MeV中微子的短爆发释放出来的。中微子光度、风味分配和平均能量的时间演化的测量也是通过引力波直接了解超新星动力学的窗口。铅作为超新星中微子的靶材料，其核物理性质对电子中微子通量的电荷电流相互作用具有明显的敏感性，对电子反中微子通量的电荷电流相互作用完全不敏感，对所有中微子性质的中性电流激发通道具有次要的敏感性。对超新星动力学的详细了解是大规模计算物理工作的前沿，结合观测数据，提供了提取基本中微子属性的可能性，并促进了我们对超新星机制、重元素核合成和其他天体物理问题的理解。*Halo-1kT是一台建议在意大利国家中微子实验室(LNGS)建造的铅基超新星中微子探测器。这是SNOLAB成功的但更小的光晕探测器的演变。Halo-1kT的灵敏度预计会比Halo高出25倍。这项科学合作由加拿大牵头，意大利和美国的主要团体参与其中。该SAP项目赠款申请是通过最终敲定完整的实验提案，通过CFI申请资本资金，以及研究和准备实验部署，为加拿大集团提供稳定和充足的资金。Halo-1kT是及时和可能的，这是因为在SNOLAB建造和运行Halo的经验；从OPERA实验获得1000吨铅的可用性；LNGS重振其超新星探测能力的热情；以及美国暂停分配He-3并通过能源部同位素计划再次提供。无论是Halo还是Halo-1kT，在超新星相关能量下的中微子-铅截面已知之前，都不能说是完全理解和校准的。这里申请的资金的一部分将支持橡树岭国家实验室散裂中子源的这些横截面的测量。然而，对横截面测量的大部分支持来自麦克唐纳研究所(MI)、劳伦斯大学、INFN、华盛顿大学LNGS和SNOLAB的组合，以及CFI-JELF正在准备的提交。*****

A type II supernova is powered by the energy liberated in the gravitational collapse of the core of a massive star. Post core collapse, the initially very hot proto-neutron star cools primarily by the emission of neutrinos, of all flavours, roughly equally partitioned. In fact, about 99% of the initial gravitational potential energy is released in a short burst of ~10 MeV neutrinos over a few tens of seconds. The measurement of the time evolution of the neutrino luminosity, flavour partition, and average energy is a direct window into supernova dynamics though a gravitational wave is also anticipated. The nuclear physics of lead, as a target material for the supernova neutrinos, provides for a dominant sensitivity to charged current (CC) interactions of the electron neutrino flux; complete insensitivity to CC interactions of the electron antineutrino flux; and minor sensitivity to all neutrino flavours through neutral current excitation channels. A detailed understanding of supernova dynamics is at the forefront of large-scale computational physics efforts and, when combined with observational data, offers the possibility of extracting fundamental neutrino properties as well as advancing our understanding of the supernova mechanism, heavy element nucleosynthesis, and other astrophysical questions.******HALO-1kT is a proposed lead-based supernova neutrino detector to be constructed at the Laboratori Nazionali del Gran Sasso (LNGS) in Italy. It is an evolution of the successful, but smaller, HALO detector at SNOLAB. HALO-1kT is expected to outperform HALO by a factor of 25 in sensitivity. The scientific collaboration is Canadian-led with major participation by Italian and American groups. This SAP Project grant application is for stable and adequate funding for the Canadian group through the finalization of the full Experimental Proposal; the application for capital funding through CFI; and studies and preparations for experiment deployment. HALO-1kT is timely and possible due to the experience gained in the construction and operation of HALO at SNOLAB; the availability of 1000 tonnes of lead from the OPERA experiment and the enthusiasm at LNGS to re-invigorate their supernova detection capabilities; and the end of the American moratorium on the distribution of He-3 and its availability once again through the DOE Isotope Program. Neither HALO nor HALO-1kT can be claimed to be fully understood and calibrated until the neutrino-lead cross sections are known at supernova-relevant energies. A component of the funds requested here will support a measurement of these cross sections at Oak Ridge National Laboratory's Spallation Neutron Source. However, the bulk of the support for the cross section measurement is coming from a combination of the McDonald Institute (MI), Laurentian University, INFN, University of Washington, LNGS, and SNOLAB and a CFI-JELF submission in preparation. *****