Physics Commons^™

Design And Model Of The Frame For Hagrid (Hybrid Array Of Gamma Ray Detectors), Santiago Munoz

Masters Theses

Transfer reactions in inverse kinematics have provided critical information in the study of exotic nuclei. However, transfer reactions with charged particles suffer from poor resolution. The measurement of gamma-rays offers several advantages: they provide not only good resolution in measurements but also other information about the nuclei like lifetimes of unstable states. The combination of these two methods would be the ideal situation to gather information about nuclear structure.

HAGRiD, which stands for The Hybrid Array of Gamma Ray Detectors, is a LaBr3(Ce) [lanthanum bromide crystal with a cerium activator] scintillation array to measure gamma rays from transfer reactions and …

Thick Target Yield Of Th-229 Via Low Energy Proton Bombardment Of Th-232, Justin Reed Griswold

Masters Theses

Actinium-225 is one of the more effective radioisotopes used in alpha radioimmunotherapy. Due to its ten-day half-life, it is more efficient to create its precursor, ²²⁹Th [Thorium-229] (t_1/2[half-life] = 7932 ± 55 years). In this work, ²²⁹Th was produced via 40 MeV [Mega electron Volts] proton bombardment of a thick ²³²Th [Thorium-232] target. The irradiation took place at the Holifield Radioactive Ion Beam Facility (HRIBF) at Oak Ridge National Lab (ORNL). The target, consisting of 23 stacked natural thorium foils (137 mg/cm² [milligrams per square centimeter] each), was irradiated with 50 nA [nanoamps] of …

Radiation-Induced Radicals In Polyurea-Crosslinked Silica Aerogel, Benjamin Michael Walters

Masters Theses

Free radicals are atoms or molecules with an odd number of electrons in an outer shell. Since electrons typically occur in pairs, this leaves one electron that is unpaired. In seek of another electron to pair with, free radicals react with and steal electrons from neighboring molecules, which then become free radicals themselves. This can start a chain reaction, cascading into large scale damage.

Ionizing radiation can tear through molecules, just as bullets can tear through things that we see. If free radicals can be detected, and seen to increase in a material upon radiation exposure, this can indicate molecular …

Microwave Assisted Reconstruction Of Optical Interferograms For Distributed Fiber Optics Sensing & Characterization Of Pcb Dielectric Properties Using Two Striplines On The Same Board, Lei Hua

Masters Theses

"A new concept, the microwave-assisted reconstruction of an optical interferogram for distributed sensing, was developed to resolve both the position and reflectivity of each sensor along an optical fiber. This approach involves sending a microwave-modulated optical signal through cascaded fiber optic interferometers. The optical spectrum of each sensor can be reconstructed by sweeping the optical wavelength and detecting the modulation signal. A series of cascaded fiber optic extrinsic Fabry-Perot interferometric sensors was used to prove the concept. The microwave-reconstructed interferogram matched well with those recorded individually from a traditional optical spectrometer. The application of distributed strain measurement was also investigated. …