A Superthermal Source at NCState University

我们正在进行一个项目，在一个低功率的大学反应堆上建造一个世界级的超热超冷中子（UCN）源。在过去的五年里，美国洛斯阿拉莫斯国家实验室和国家标准与技术研究所的研究小组在开发超热ucn源方面取得了巨大的进步，令人信服地证明了这些资源的物理性质是可以理解的。在可用的超热源的密度数量级的改善可能是可以达到的。拟议中的核电站的强度将与美国和国外目前正在规划的所有核电站相当，并且比目前正在运行的任何核电站都要强得多。合作包括参与基本对称性研究的核物理学家和专门从事反应堆冷源和慢化剂开发的核工程师。使用低能中子的研究项目是由ucn在基本核物理测量方面的实用性所驱动的，例如对核子的静电偶极矩和核子的带电弱电流形式因素的测量进行限制。这些测量对当今物理学面临的一些最深刻、最基本的问题产生了影响。随着超热源处可用UCN通量的增加，UCN作为表面氢层和大型生物分子的非破坏性探针的新应用也可能得到发展。

We are undertaking a program to construct a world-class, superthermalultracold neutron (UCN) source at a low power, university-basedreactor. In the past five years, research groups at Los Alamos NationalLaboratory and the National Institute of Standards and Technology in theUnited States have made great strides in the development of superthermalUCN sources, demonstrating convincingly that the physics of thesesources is understood. Orders of magnitude improvement in available UCNdensities with superthermal sources may be within reach. The proposedsource will be comparable in strength to essentially all of thefacilities currently being planned in the U.S. and abroad, andconsiderably stronger than any presently operating source. Thecollaboration comprises nuclear physicists involved in fundamentalsymmetries research and nuclear engineers who specialize in reactor coldsource and moderator development. Research programs using low-energyneutrons are driven by the proven usefulness of UCNs for fundamentalnuclear physics measurements, such as placing limits on the staticelectric dipole moments of nucleons and the measurement of the chargedweak current form factors of the nucleon. These measurements haveimpact on some of the deepest and most fundamental questions confrontedby physics today. With the increased UCN flux available at superthermalsources, the development of new applications for UCN as non-destructiveprobes of surface hydrogen layers and large biological molecules mayalso be posssible.