A Superthermal Source at NCState University

我们正在进行一项计划，在大学的低功率反应堆中建造世界一流的超热超冷中子 (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超高温超高温宇宙核源的开发方面取得了长足的进步，令人信服地证明了这些源的物理原理已被了解。 利用超热源将可用 UCN 密度提高几个数量级可能是可以实现的。 拟议的能源的强度将与美国和国外目前正在规划的几乎所有设施相当，并且比任何目前正在运行的能源都要强大得多。 该合作由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组成。 使用低能中子的研究计划是由UCN在基本核物理测量中已被证实的有用性所驱动的，例如对核子的静电偶极矩进行限制以及对核子的带电弱电流形状因子的测量。 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 UCN 通量的增加，开发 UCN 作为表面氢层和大生物分子的非破坏性探针的新应用也成为可能。

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.