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

North Carolina State University, Raleigh NC

Investigators

Abstract

he UCNA project has essentially completed construction of their experiment to measure the beta-asymmetry in the decay of the neutron using ultracold neutrons (UCN). The UCN source developed for this measurement, a solid-deuterium superthermal source coupled to a spallation target at the 800 MeV proton beam at LANSCE, is the first such source to be constructed. When fully operational, this source promises ample UCN for the first measurements of the beta-asymmetry. The preliminary goal of the UCNA collaboration is a measurement of the beta-asymmetry to a precision of 0.2 percent. During the next funding period, we plan to refine this measurement, increasing the precision of the beta-asymmetry (in part by implementing several different beta detection systems) and initiating a program to measure the other angular correlations involving detection of the recoil proton following beta-decay. The existence of this new source will also make possible the investigation of new uses of UCN for both fundamental and applied physics research.