A5086960826- Nuclear reactor physics and engineering
- Nuclear Materials and Properties
- Radiation Therapy and Dosimetry
- Radiation Detection and Scintillator Technologies
- Fusion materials and technologies
- Radiation Effects in Electronics
- Nuclear Engineering Thermal-Hydraulics
- Nuclear Physics and Applications
- Metal and Thin Film Mechanics
- Gaussian Processes and Bayesian Inference
- Thermal properties of materials
- Phase Change Materials Research
- Semiconductor materials and devices
- Gas Dynamics and Kinetic Theory
- Ion-surface interactions and analysis
- Probabilistic and Robust Engineering Design
- Particle accelerators and beam dynamics
- Muon and positron interactions and applications
- Diamond and Carbon-based Materials Research
- Spacecraft and Cryogenic Technologies
- Fault Detection and Control Systems
- Advanced Thermoelectric Materials and Devices
- Radiative Heat Transfer Studies
- Advanced Radiotherapy Techniques
- Additive Manufacturing Materials and Processes
Texas A&M University
2009-2023
Ames Research Center
2015
The tissue-equivalent proportional counter (TEPC)-based dosemeters used on the International Space Station have exceeded their planned useful lives, and are scheduled to be replaced with new units taking advantage of improved technology. original TEPC detectors cylindrical geometry field tubes achieve good energy resolution minimum sensitivity noise created by vibration. inside diameter these is 5.1 cm. developed for this application produce vibration resistance detector isotropic response...
Effects on human health from the complex radiation environment in deep space have not been measured and can only be simulated here Earth using experimental systems beams of radiations produced by accelerators, usually one beam at a time. This makes it particularly important to develop instruments that used deep-space missions measure quantities are known relatable biological effectiveness radiation. Tissue-equivalent proportional counters (TEPCs) such instruments. Unfortunately, present...
A fluidized bed chemical vapor deposition (FB-CVD) system with an inverted reactor was used to develop barrier coatings of zirconium nitride on the surface U 8 wt% Mo microspheres in order examine resulting coating structure and composition, as well evaluate effects certain process parameters properties. The utilized metal-organic precursor tetrakis(dimethylamino)zirconium heated 51°C ± 2°C. Time-dependent studies analyzed produced after 2 days operation at 100 mL/min carrier flow rate 500...
AbstractAbstractIn this work a new single anode spherical tissue-equivalent proportional counter (TEPC) was developed for mixed field radiation dosimetry. The approach used to divide the cathode into several rings with different thicknesses and adjust potential difference between each ring produce an electric that is nearly constant along length of anode. A-150 plastic detector walls, insulator material low-density polyethylene, gas inside propane. detector, charge sensitive preamplifier,...
A fluidized bed–chemical vapor deposition (FB-CVD) process was designed and established in a two-part experiment to produce zirconium nitride barrier coatings on uranium-molybdenum particles for reduced enrichment dispersion fuel concept. hot-wall, inverted bed reaction vessel developed this process, were produced from thermal decomposition of the metallo-organic precursor tetrakis(dimethylamino)zirconium (TDMAZ) high-purity argon gas. Experiments executed at atmospheric pressure low...
In this experiment, Type 316L stainless steel rods were fabricated through laser additive manufacturing (LAM) in three different orientations, and microstructural mechanical changes induced by high dose ion irradiation characterized based on orientation. The irradiated with Fe2+ self-ions to a peak of 80 displacements per atom at 475°C. Results compared concurrently conventionally manufactured control specimens. Electron backscatter diffraction the yielded statistically relevant information...
Abstract Model calibration uses outputs from a simulator and field data to build predictive model for the physical system estimate unknown inputs. The conventional approach assumes that observations are continuous outcomes. In many applications this is not case. methodology proposed was motivated by an application in modeling photon counts at Center Exascale Radiation Transport. There, high performance computing used simulating flow of neutrons through various materials. article, new...
Neutrons produced from the interaction between galactic cosmic rays and spacecraft materials are responsible for a very important portion of dose received by astronauts. The neutron energy spectrum depends on incident charged particle scattering environment but generally extends to beyond 100 MeV. Tissue-equivalent proportional counters (TEPC) used measure during space mission, their weight size factors design construction. To achieve ideal dosimetry, wall thickness should be at least range...
Two of the experiment vehicles being developed for Versatile Test Reactor (VTR) are presented here. The first is a rabbit system that will enable rapid insertion small test capsules into high fast flux VTR core relatively short durations. concept development includes construction/demonstration near-full-scale in deep-water pool to demonstrate functionality, operations and initial procedures, validation thermal-hydraulic modeling. In addition, modeling efforts underway simulate thermal...