Teledyne e2v HiRel Microdosimeter is a compact hybrid microcircuit which directly measures total ionizing dose (TID) absorbed by an internal silicon test mass. The test mass simulates silicon die of integrated circuits on-board a host spacecraft in critical mission payloads and subsystems. By accurately measuring the energy absorbed from electrons, protons, and gamma rays, an estimate of the dose absorbed by other electronic devices on the same vehicle can be made. The Microdosimeter can operate from a wide range of input voltages. The accumulated dose is presented to three dc linear outputs and one pseudo-logarithmic output giving a dose resolution of 14 µrads and a measurement range up to 40 krads. These outputs are intended to be directly connected to most analog-to-digital converters (ADCs) or spacecraft housekeeping analog inputs (0-5 V range), which makes minimal demands on the host vehicle. The Microdosimeter incorporates a test function to allow electrical testing of the hybrid without the need for a radiation source.

Three new variants to the standard Microdosimeters (NuDOS) provide low, medium, and high energy range coverage to discriminate radiation effects associated with exposed materials and components having varying degrees of shielding in a spacecraft system. The detector can be left open to space, lightly shielded by a thin foil, or heavily shielded with custom covers. A system of several dosimeters can be arranged to provide some spectral information about the environment. The electronics require a 5-volt input for simple integration within most electronic systems on a space vehicle.