Engineering topics
Publications and source records attributed to Dawson, S. F..
A review of the radiation effects investigation capabilities of the JPL Dynamitron Accelerator Facility are discussed. A process for its use in performing total ionizing dose (TID) studies are outlined. The results of radiation effects in complicated test systems where device effects may occur due to local system irradiation are also presented.
Future NASA missions are driving a need for instrumentation and space electronics that will operate at extreme temperatures, with low mass and extended deployments. This need results in devices that will experience dose damage at both low and high temperatures that will suppress annealing and induce accelerated wear out issues. Therefore, the ability to perform radiation tests on devices at temperature is critical. This paper analyses the methods and process to enable these test as developed at the JPL Dynamitron Facility. Since electronics are the radiation source for this facility, the steps to ensure parity with cobalt-60 testing are discussed. Also discussed are the implications for system level testing and mixed radiation mode testing for highly integrated and scaled devices.
No abstract available
Future NASA exploration missions to Mars, Europa, Titan, comets and asteroids are seeking to perform sampling, in-situ analysis and possibly return of material to Earth for further tests.
Influence of raw material source, processing methods, and cell operating voltage limits on the performance of TiS2 cathode was examined. Raw materials obtained from three different sources were investigated. TiS2 electrodes were fabricated by painting, rolling, and pressing methods. Raw materials and electrodes were characterized for their physical, chemical, and electrochemical properties. The results obtained indicated that the performance of TiS2 cathodes was dependent on the purity and stoichiometry of the TiS2 material. Fabrication methods were found to have minimal influence on the performance of cathodes. The capacity loss observed during the early stages of cycling was attributed to the trapping of lithium in TiS2. Operating voltage limits were found to have significant influence on the cycle life performance of the cells.