Abstract by Adam Christensen

Personal Infomation

Presenter's Name

Adam Christensen

Degree Level


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Physics and Astronomy

Faculty Advisor

Larry Rees


Hybrid Neutron Detection Using Optical Characterization of Gadolinium-Acrylic Sheets in Liquid Scintillator


Before low-cost, hybrid neutron detectors can be tested, they must be able to produce strong optical signals. We studied the optics of detector designs with varying numbers of 2 mm-thick acrylic disks in mineral oil in order to simulate actual detector conditions. Transmission and reflection coefficients were determined using laser optics and compared to theoretical models of Fresnel Coefficients. The optical signal strength of multiple detector geometries was evaluated. As a supplement, simulations for an actual detector were then created using the code MCNP (Monte Carlo for Neutral Particles). Acrylic transmission spectra showed maximums above 400 nm. Mineral oil absorption spectra revealed near 78% absorption near 400 nm. Optical signal strength tests with 3+ acrylic disks yielded signals indistinguishable from 40 meV noise, indicating significant light absorption.  MCNP simulations of the detector predicted average light output of about 0.5 MeVee (MeV electron equivalent) suggesting that a similar detector would be optically viable.