Honors Program

Honors in Physics and Astronomy

Date of Award


Thesis Professor(s)

Robert W. Pattie Jr.

Thesis Professor Department

Physics and Astronomy

Thesis Reader(s)

Gary Henson


The UCNA Experiment at the Los Alamos Neutron Science Center (LANSCE) uses an electron spectrometer to observe angular correlations between the neutron spin and the momenta of β particles emitted during the process of β decay. These angular correlations give rise to an asymmetry determined by the ratio of two coupling constants, gA and gV . Combined with neutron lifetime measurements, these observations probe physics beyond the standard model through unitarity tests of the Cabbibo-Kobayashi-Maskawa Matrix. UCNA’s current spectrometer uses a multi-wire proportional chamber and a plastic scintillator coupled to four photomultiplier tubes (PMTs) by 2 meters of light guides to record energy, position, and time data. The UCNA Collaboration is exploring ways to modernize the detector package using silicon photomultipliers (SiPMs) to increase the sensitivity of the experiment. The new configuration of the spectrometer is expected to improve systematic uncertainties; namely the 2 meter path the produced light must travel to reach the PMTs and the SiPMs’ quantum efficiency being a factor of 2 greater than the prior PMTs’. The subject of this paper is a prototype detector for evaluating the SiPMs as the only detectors present, the goal being to compare the position and energy resolution with that of the current spectrometer in use at UCNA.


East Tennessee State University

Document Type

Honors Thesis - Open Access

Creative Commons License

Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 License.


Copyright by the authors.