Neon moderator for intense cold positron source

强冷正电子源氖慢化剂

• 批准号: 344895-2007
• 负责人: Hessels, Eric
• 金额: $ 5.63万
• 依托单位: York University
• 依托单位国家: 加拿大
• 项目类别: Research Tools and Instruments - Category 1 (<$150,000)
• 财政年份: 2006
• 资助国家: 加拿大
• 起止时间: 2006-01-01 至 2007-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=326016
• 关键词: Neon; moderator; intense; cold; positron

Neon Moderator for an intense positron source Antihydrogen is the simplest antimatter atom and consists of a positron (the antiparticle equivalent of an electron) orbiting about an antiproton. In recent years, antihydrogen atoms have been constructed at CERN by combining trapped antiprotons with trapped positrons. The goal of this research is to precisely study antihydrogen atoms and compare their properties to those of regular hydrogen, thus comparing the properties of antimatter to those of matter. Because of a fundamental symmetry of physics (CPT), it might be expected that the properties will be exactly identical and the comparison will therefore test CPT symmetry. The monies requested are to fund an improved method for collecting positrons. The positrons are produced at very high energy by a sodium-22 radioactive source. A moderator is used to lower their energy by having a small fraction of the positrons thermalize within a solid. Currently we are using a thin crystal of tungsten for this purpose, but the number of positrons available to our experiment could be improved by a factor of 100 if we were to use a solid neon moderator instead. The factor of 100 results from the 10 times higher positron moderation efficiency of solid neon combined with the fact that the resulting higher density allows for better compression of the positron plasma and this compression leads to a factor of 10 higher efficiency in transporting the positrons to the location where the antiprotons are trapped. The grant proposal is for the purchase of a system which will allow us to produce and sustain a solid neon moderator. This moderator must be constructed and maintained at temperatures below 24 Kelvin (-250 degrees Celsius) and require a precision-controlled ultrapure gas system within a high-vacuum apparatus.

反氢是最简单的反物质原子，由一个围绕反质子运行的正电子(相当于电子的反粒子)组成。近年来，欧洲核子研究中心通过将捕获的反质子和捕获的正电子结合在一起，构建了反氢原子。这项研究的目的是精确地研究反氢原子，并将它们的性质与普通氢的性质进行比较，从而将反物质的性质与物质的性质进行比较。由于物理的基本对称性(CPT)，可以预期属性将完全相同，因此比较将测试CPT对称性。所要求的资金是为了资助一种改进的收集正电子的方法。正电子是由钠-22放射源以非常高的能量产生的。慢化剂被用来降低它们的能量，方法是让一小部分正电子在固体中热化。目前，我们正在使用一种薄的钨晶体来实现这一目的，但如果我们使用固体霓虹灯慢化剂，那么我们实验中可用的正电子数可能会提高到原来的100倍。100倍的原因是固体霓虹的正电子慢化效率提高了10倍，加上由此产生的更高的密度允许更好地压缩正电子等离子体，这种压缩导致将正电子传输到反质子捕获位置的效率提高了10倍。赠款提案是为了购买一个系统，该系统将使我们能够生产和维持一个可靠的霓虹灯慢化器。这种慢化剂必须在24开尔文(-250摄氏度)以下的温度下建造和维护，并需要在高真空设备中使用精确控制的超纯气体系统。