Ultracold neutrons at TRIUMF: bridging grant for new member

TRIUMF 超冷中子：为新成员提供过渡补助金

• 批准号: SAPPJ-2017-00045
• 负责人: Franke, Beatrice
• 金额: $ 2.91万
• 依托单位: TRIUMF
• 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=651075
• 关键词: Ultracold; neutrons; TRIUMF; bridging; grant

The matter-antimatter asymmetry in the universe is one of the biggest questions in fundamental physics, as well as philosophy. The neutron electric dipole moment (nEDM) is related to this asymmetry and can thus help shed light on this unsolved puzzle. Experiments searching for the nEDM have also ruled out several particle physics theories over the last five decades. So far, the most stringent limits on the nEDM have been set by experiments using ultracold neutrons; these are so slow that they are reflected by certain wall materials and can subsequently be stored and observed for hundreds of seconds.***TRIUMF's Ultracold Neutron program aims at providing the world's highest intensity of ultracold neutrons (UCN) to experiments. Furthermore, the Canadian-Japanese collaboration behind the TRIUMF UCN project wants to achieve a world leading ultimate sensitivity of 10−27 ecm to the nEDM. This search constitutes the flagship experiment of UCN physics.******The research program suggested in this proposal extends over two years and is intended as bridging grant for a new collaboration member. The rest of the UCN collaboration is supported by NSERC grant SAPPJ-2016-00024. The co-applicant is the principal applicant of this existing grant and is signing this application for administrative purposes only.***The main goal of this research proposal is the successful integration of the nEDM apparatus into the TRIUMF UCN facility. Two milestones are (i) filling and storing UCN into the existing Phase 1 nEDM apparatus, and (ii) the observation of Larmor precession of the stored UCN. This is very challenging due to the harsh environmental conditions in the direct proximity of the cyclotron accelerator which include (among others) high magnetic background fields, as well as time varying magnetic fields caused by other close-by experiments and infrastructure such as cranes and loading doors. The stability and homogeneity of the magnetic field, however, are crucial ingredients to the feasibility of Larmor precession experiments, and subsequently to the sensitivity of an nEDM measurement.***The applicant has gathered ample expertise in magnetic field observation and manipulation, as well as with nEDM measurements during her PhD studies and additionally is very experienced with UCN experiments by participating in UCN measurement campaigns at the institutes FRM-II in Germany, ILL in France, and PSI in Switzerland through her entire scientific career. This will be essential to the success of the UCN source and EDM experiment at TRIUMF.**

宇宙中物质-反物质的不对称性是基础物理学和哲学中最大的问题之一。中子电偶极矩(NEDM)与这种不对称性有关，因此可以帮助解开这个未解之谜。在过去的50年里，寻找nEDM的实验也排除了几种粒子物理理论。到目前为止，对nEDM最严格的限制是通过使用超冷中子的实验设定的；这些限制是如此之慢，以至于它们被某些壁材反射，随后可以存储和观察数百秒。*TRIUMF的超冷中子计划旨在为实验提供世界上最高强度的超冷中子(UCN)。此外，TRIUMF UCN项目背后的加拿大和日本合作希望实现世界领先的10−27 ECM对非电火花加工的最终灵敏度。这项研究构成了UCN物理学的旗舰实验。*本建议中建议的研究计划持续两年以上，旨在为新的合作成员提供过渡性资助。联盟协作的其余部分由国家经济合作与发展委员会赠款SAPPJ2016-00024支持。共同申请人是这项现有赠款的主要申请人，并仅出于行政目的签署本申请。*本研究提案的主要目标是成功地将nEDM设备整合到TRIUMF UCN设施中。两个里程碑是(I)将UCN填充并存储到现有的第一阶段nEDM设备中，以及(Ii)观察到存储的UCN的Larmor进动。这是非常具有挑战性的，因为回旋加速器直接附近的恶劣环境条件包括(除其他外)高磁场背景场，以及由其他邻近实验和基础设施(如起重机和装载门)引起的时变磁场。然而，磁场的稳定性和均匀性是Larmor进动实验的可行性以及随后的nEDM测量灵敏度的关键因素。*申请人在攻读博士学位期间积累了丰富的磁场观测和操纵以及nEDM测量方面的专业知识，此外，她在整个科学生涯中参与了德国FRM-II研究所、法国ILL研究所和瑞士PSI研究所的UCN测量活动，因此对UCN实验非常有经验。这将对TRIUMF的UCN源和EDM实验的成功至关重要。**