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Articles 1 - 5 of 5
Full-Text Articles in Physics
Pulse Height Spectra Analysis Of A Neutron Energy Tuning Assembly, Jason R. Stickney
Pulse Height Spectra Analysis Of A Neutron Energy Tuning Assembly, Jason R. Stickney
Theses and Dissertations
An energy tuning assembly (ETA) was previously designed and built for the purpose of irradiating samples with a combination of a thermonuclear and a prompt fission neutron spectrum. Initial research was performed to characterize the performance of the ETA at the Lawrence Berkeley National Laboratory 88-Inch Cyclotron using 33 MeV deuteron breakup on tantalum as the neutron source. This research analyzes detector responses collected from three EJ-309 detectors used to characterize the ETA generated neutron field. A signal processing chain was developed to reduce the full waveform data into a pulse height spectrum. The primary goal was to develop a …
The Combined Effects Of Radio Frequency And Gamma Irradiation On P-Channel Mosfets, Joshua D. Daniel
The Combined Effects Of Radio Frequency And Gamma Irradiation On P-Channel Mosfets, Joshua D. Daniel
Theses and Dissertations
The purpose of this research was to investigate the combined effects of continuous gigahertz radio frequency signals and gamma irradiation on the threshold voltage of metal oxide semiconductor field effect transistors. The combined effects of gigahertz radio frequency waves and gamma irradiation on electronics presents a new challenge in electronic warfare and little is known of the combined effect on threshold voltage damage and recovery. The Fairchild NDS352AP, a commonly used commercial device, was irradiated by a cobalt-60 source under a +5 V bias with and without a radio frequency signal applied to the gate. The threshold voltage was measured …
Thermal Neutron Point Source Imaging Using A Rotating Modulation Collimator (Rmc), Nathan O. Boyce
Thermal Neutron Point Source Imaging Using A Rotating Modulation Collimator (Rmc), Nathan O. Boyce
Theses and Dissertations
This thesis demonstrates a previously untested capability of the Rotating Modulation Collimator (RMC) to image a point-like neutron source. The encouraging results, achieved using low-energy neutrons, provide motivation for further refinement and continued research with higher-energy neutrons. The detector and the masks on an existing RMC imaging system were exchanged to function with neutrons. The source in this research produced a poly-energetic spectrum of neutrons through the reaction. The source of alpha particles was a 72.7 mCi 239Pu source. The RMC detector was located 250 cm from the bare source and operated for three hours to generate a modulation …
In-Situ, Gate Bias Dependent Study Of Neutron Irradiation Effects On Algan/Gan Hfets, Janusz K. Mikina
In-Situ, Gate Bias Dependent Study Of Neutron Irradiation Effects On Algan/Gan Hfets, Janusz K. Mikina
Theses and Dissertations
AlGaN/GaN Heterostructure Field Effect Transistors (HFETs) have come under increased study in recent years due to their highly desirable material and electrical properties and survivability even during and after exposure to extreme temperature and radiation environments. In this study, unpassivated and SiN passivated Al0.27Ga0.73N/GaN HFETs were subjected to neutron radiation at 120 K. The primary focus of the research was the effects of neutron irradiation on drain current, gate leakage current, threshold voltage shift, gate-channel capacitance, and the effects of biasing the gate during irradiation. In-situ measurements were conducted on transistor current, gate-channel capacitance, and gate …
Positron Annihilation Ratio Spectroscopy (Psars) Applied To Positronium Formation Studies, Robert C. Slaughter
Positron Annihilation Ratio Spectroscopy (Psars) Applied To Positronium Formation Studies, Robert C. Slaughter
Theses and Dissertations
A Positron Annihilation of Radiation Spectrometer (PsARS) was developed and characterized. PsARS spectroscopy as well as digital Positron Annihilation Lifetime Spectroscopy (PALS) was applied to measure positronium formation on gold nanoparticles deposited through an evaporative method onto a thin capillary tube. This gold coated capillary tube was designed to be used for positronium lifetime studies in local electric field experiments. High local electric fields can polarize a positron-electron pair, which may result in an extended lifetime of the positron. These fields may be created through the interaction of an external electric field with silver nanoparticles deposited onto the surface of …