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Full-Text Articles in Materials Science and Engineering
Radiation Exposure Calibration Of The Al2o3:C With Radium-226 And Cesium-137 Using The Osl Method, Selma Tepeli Aydin
Radiation Exposure Calibration Of The Al2o3:C With Radium-226 And Cesium-137 Using The Osl Method, Selma Tepeli Aydin
All Theses
Optically stimulated luminescence (OSL) dosimetry was utilized to calibrate Al2O3:C powder dosimeters, available commercially as the nanoDot® from Landauer Inc., and compare the dosimeter response to radium-226 (226Ra) and cesium-137 (137Cs). The signal from the OSL was quantified using a microSTARii® OSL reader also produced by Landauer Inc. Dose-response curves were developed for 226Ra and 137Cs experiments (5 dosimeters each) at thirteen absorbed doses. Individual dosimeter response was tracked by serial number. Linear regression analysis was performed to determine if there were significant differences between the intercepts of the …
Sub-Bandgap Photon-Assisted Electron Trapping And Detrapping In Algan/Gan Heterostructure Field-Effect Transistors, Andrew Gunn
Sub-Bandgap Photon-Assisted Electron Trapping And Detrapping In Algan/Gan Heterostructure Field-Effect Transistors, Andrew Gunn
All Theses
We have investigated photon-assisted trapping and detrapping of electrons injected from the gate under negative bias in a heterostructure field-effect transistor (HFET). The electron injection rate from the gate was found to be dramatically affected by sub-bandgap laser illumination. The trapped electrons reduced the two-dimensional electron gas (2DEG) density at the AlGaN/GaN heterointerface but could also be emitted from their trap states by sub-bandgap photons, leading to a recovery of 2DEG density. The trapping and detrapping dynamics were found to be strongly dependent on the wavelength and focal position of the laser, as well as the gate bias stress time …
Near-Earth Ion Irradiation Effects On Functional Ceramic Materials: A Combined Experimental-Monte Carlo Approach, William J. Sands
Near-Earth Ion Irradiation Effects On Functional Ceramic Materials: A Combined Experimental-Monte Carlo Approach, William J. Sands
All Theses
The near-Earth space radiation environment is a complex system that creates a harmful environment for materials to operate in. Motivated by the search for using optical defects as an indicator of radiation damage, five single-crystal functional ceramic materials were selected to undergo ion irradiation at conditions found in the near-Earth space environment. Due to the complex nature of ion irradiation effects in ceramic materials, a host of calculations and experimental characterization methods were used. Calculations using the 2013 SRIM code were used to evaluate the ion projected range and the type and number of defects (vacancies) created by ion irradiation. …