The DIME-1 Experiment Flown as Part of NASA’s SET-1 Project on the DSX Satellite

Dosimetry Intercomparison and Miniaturization Experiment (DIME-1) is an experiment flying as part of NASA’s Space Experimental Testbed (SET-1) satellite project on the Air Force’s Demonstration and Science Experiments (DSX) satellite to compare novel dosimeters with the standard radiation field-effect transistor (RadFET) dosimeters. It consists of five operational RadFETs under different thicknesses of hemispherical Al and Ta shields and three commercial-off-the-shelf (COTS) floating-gate MOS transistor (FGMOS) UV Proms programmed as dosimeters. The flight path crosses the entire slot region and cuts the Van Allen belts on each 5.25-h orbit of the Earth. The dosimeters on DIME-1 and its sister board DIME-2, consisting of two linear energy transfer (LET) spectrometers, are capable of measuring total ionizing dose (TID) and single-event effects (SEEs) which are responsible for degrading or causing catastrophic failure of electronic circuits in space. Results comparing the different dosimeters with the standard RadFET devices are shown to be in quite good agreement in terms of the shape of the total dose versus time plots over the 1.75 year life of the DSX mission but not in agreement over the TID measured presumably due to short-range protons reaching the sensitive volume of FGMOS devices but not reaching that of RadFETs. DIME-1 traveled into a radiation environment that well-designed circuits, flown during solar minimum, will survive.