Commissioning of Ultra-Cold Neutron Asymmetry Spectrometer

• Main Author: Hsiao, Jennifer Ying
• Published: 2006
• Online Access: Hsiao, Jennifer Ying (2006) Commissioning of Ultra-Cold Neutron Asymmetry Spectrometer. Senior thesis (Major), California Institute of Technology. doi:10.7907/8d5z-bz25. https://resolver.caltech.edu/CaltechTHESIS:02132018-112803276 <https://resolver.caltech.edu/CaltechTHESIS:02132018-112803276>

We can feasibly probe for physics beyond the Standard Model of particle physics with more accurate and precise results from neutron beta decay experiments. An ultracold neutron (UCN) beta decay experiment will begin this year at the Los Alamos Neutron Science Center (LANSCE). This experiment will perform a precision measurement of the neutron betaasymmetry (or the A-correlation), which is the correlation between the neutron's spin and the momentum of the emitted decay electron. A precise measurement of the A-correlation, combined with a value for the neutron lifetime, can be used to test the unitarity of the Standard Model's quark-electroweak mixing matrix. Prior to commencement, the 1 Tesla field superconducting spectrometer constructed for the experiment by Caltech must be fully calibrated. A position and energy resolution study of the plastic scintillator and MWPC was accomplished using thin film conversion line sources, ¹¹³Sn and ²⁰⁷Bi, placed at the center of the spectrometer.