Interaction of Ammonium Sulfide with the Semiconductor Surfaces of AlSb and Related Alloys.
Abstract not provided.
Renteria, Emma↗
Engineering topics
Hecht, Adam
Publications and source records attributed to Hecht, Adam.
Fission Fragment Yield Data in Support of Advanced Reactor Technology
Within the 3 year POP we propose to continue to test and further develop the fission spectrometers, to do development tests and full data acquisition run at the national laboratory neutron beam facilities, to measure correlated fission fragment yields at low neutron energies with 235 U fission targets, and make these data available to the nuclear community. The spectrometer development will be both on the university based r\prototype and on the National Laboratory Spectrometer, and measurements will be performed with both. Over the longer time frame of the collaboration, we will take data over a range of low energies, and use other fission targets available to the laboratory. We will gather energy specific fragment distributions and reaction cross sections. We will further develop the data acquisition capabilities to take correlated fission fragment'gamma ray/neurton data, all on an event-by-event basis. This really is an enabling technology.
21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗
Thin Film Solid State Active Dosimetry
With the many advances in semiconductor manufacturing, the pool of available materials for use in their production also continues to broaden. One such example is aluminum antimonide (AlSb). Its promising properties for radiation detection have attracted multiple researchers, and allow for the possibility that it may be a high resolution, room temperature x-ray/gamma detector. Antimony has an atomic number of 51 (Z=51) and is responsible for the majority of photon interactions. Furthermore, the mass attenuation coefficient is comparable with other well-known solid state gamma detectors such as CZT. With a band gap of 1.6 eV (CZT=1.5 eV), low leakage current at room temperature is expected, and high charge carrier statistics from radiation interactions can be expected. Charge carrier statistics are driven by high charge mobility (μ) and lifetime (τ). μτ for CZT is on the order of 5x10{sup -3} cm{sup 2}/V for electrons, but two orders of magnitude smaller for holes. This results in large variations in detector pulse height depending on the location of interaction (close to the anode vs. close to the cathode). Theoretically, AlSb should exhibit much more symmetric electron and hole properties near 5x10{sup -3} cm{sup 2}/V. According to the Hecht relation, this should produce a more uniform detector response and increase the number of generated charge carriers, improving resolution. An added benefit is that AlSb can be grown directly onto Si substrates, enabling fully integrated circuit board-level sensors. However, several characteristic properties remain unknown and inconsistent published results due to difficulties in producing the material. Difficulties in bulk growth methods (material interactions with growth hardware such as crystals and air) resulted in high levels of defects. The use of AlSb in optoelectronics from thin film growth methods has been documented, including growth directly onto Si, and provides the potential for much more controlled material. In our work we use thin film growth of AlSb geared towards high quality material for understanding the properties for radiation detection. (authors)
36 MATERIALS SCIENCE↗
Proposed Muon Radiography Method for Spent Fuel Cask Interrogation
Multiple scattering muon radiography is a technique that was developed at Los Alamos National Laboratory (LANL) to detect high Z material using cosmic ray muons as a radiation source. As a result,there has been considerable interest in using the technique to radiograph nuclear waste inside of storage casks. Recently,the technique has been used to interrogate the inside of a MC-10 dry fuel cask at Idaho National Laboratory (INL).This is the only technique that has been successful in imaging the interior of a spent fuel cask.The measurement was performed with the LANL Mini Muon Tracker (MMT), composed of two super-modules of drift tubes and readout electronics placed on each side of the fuel cask. The final result was a one dimensional histogram (projection) that showed areal scattering density within the cask binned according to horizontal position within the cask. While successful, the MMT is not designed for an optimal measurement of a fuel cask. The MMT only covers a limited solid angle around the cask and needs to be orientated so as to be aligned with the grid of stored fuel bundles. Even when properly aligned, the resulting areal scattering density projection indicates that a fuel bundle within a column is missing, but is ambiguous as to which row is lacking the fuel bundle. This paper discusses a potential new detector and analytical technique that may be used to better radiograph the nuclear material inside of a storage cask. (authors)
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
A compact cryogenic pump
A centrifugal cryogenic pump has been designed at Argonne National Laboratory to circulate liquid nitrogen (LN2) in a closed circuit allowing the recovery of excess fluid. The pump can circulate LN2 at rates of 2-10 L/min, into a head of 0.5-3 m. Over four years of laboratory use the pump has proven capable of operating continuously for 50-100 days without maintenance.
Centrifugal pump↗