The USNA MIDN Microdosimeter Instrument

This paper describes the MIcroDosimetry iNstrument (MIDN) mission now under development at the United States Naval Academy. The instrument is manifested to fly on the MidSTAR-1 spacecraft, which is the second spacecraft to be developed and launched by the Academy s faculty and midshipmen. Launch is scheduled for 1 September 2006 on an ATLAS-5 launch vehicle. MIDN is a rugged, portable, low power, low mass, solid-state microdosimeter designed to measure in real time the energy distributions of energy deposited by radiation in microscopic volumes. The MIDN microdosimeter sensor is a reverse-biased silicon p-n junction array in a Silicon-On-Insulator (SOI) configuration. Microdosimetric frequency distributions as a function of lineal energies determine the radiation quality factors in support of radiation risk estimation to humans.