Nuclear Resonance Fluorescence on Th-232 (2011)
Undergraduate: Alexander Hill
Faculty Advisor: Hugon Karwowski
Department: Physics & Astronomy
Nuclear resonance fluorescence (NRF) is a potent tool for isotope identification via gamma-ray interrogation. NRF resonances at several energies were observed while irradiating Th-232 with a 2.95 MeV linearly-polarized, quasi-monoenergetic gamma-ray beam at the High Intensity Gamma Source (HIGS) at Triangle Universities Nuclear Laboratory. In- and out-of-plane detectors recorded the emitted gamma rays. Statistical methods such as algorithmic background subtraction and signal variance analysis identified and isolated NRF peaks, revealing asymmetries in the emitted spatial distributions of gamma-rays resulting from E1 and M1 transitions. In addition, a method of spectral unfolding for germanium gamma-ray detectors was developed to determine the energy distribution of the incident beam.