A Measurement of the Beta-Asymmetry of the Neutron Utilizing Ultracold Neutrons

UCNA项目基本上已经完成了他们使用超冷中子（UCN）测量中子衰变中的β -不对称性的实验。为这次测量开发的UCN源是一个固体氘超热源，耦合到LANSCE 800 MeV质子束的碎片靶，是第一个这样的源。当完全投入使用时，该源保证为β -不对称的首次测量提供充足的UCN。UCNA合作的初步目标是测量β -不对称性，精度达到0.2%。在下一个资助期内，我们计划改进这一测量，提高β -不对称的精度（部分通过实施几个不同的β探测系统），并启动一个项目来测量其他角相关性，包括探测β衰变后的反冲质子。这种新来源的存在也将使研究UCN在基础物理和应用物理研究中的新用途成为可能。

he UCNA project has essentially completed construction of theirexperiment to measure the beta-asymmetry in the decay of the neutronusing ultracold neutrons (UCN). The UCN source developed for thismeasurement, a solid-deuterium superthermal source coupled to aspallation target at the 800 MeV proton beam at LANSCE, is the firstsuch source to be constructed. When fully operational, this sourcepromises ample UCN for the first measurements of the beta-asymmetry. The preliminary goal of the UCNA collaboration is a measurement of thebeta-asymmetry to a precision of 0.2 percent. During the next fundingperiod, we plan to refine this measurement, increasing the precision ofthe beta-asymmetry (in part by implementing several different betadetection systems) and initiating a program to measure the otherangular correlations involving detection of the recoil proton followingbeta-decay. The existence of this new source will also make possiblethe investigation of new uses of UCN for both fundamental and appliedphysics research.