Total Ionizing Dose Measured With the Radiation Dosimeter Onboard the FY‐3E Satellite

Abstract FengYun‐3E (FY‐3E) was the first operational meteorological satellite in China in early morning orbit. The radiation dosimeter, which is part of the satellite's Space Environment Monitor (SEM), contains three probes to measure the total ionizing dose in the three directions of the satellite. Improvements in the dosimeter have been made to increase detection sensitivity. The RADFET, a radiation dose sensor, was calibrated using 60 Co radionuclide source to correlate its threshold voltage shift with the total ionizing dose. The improved dosimeter has a sensitivity of 0.06 rad (Si) to 0.45 rad (Si) in the measurement range. The flight data showed that the total ionizing dose within the FY‐3E satellite is anisotropic. The radiation dose rate in the +X and +Y directions increased by a few factors after the geomagnetic storms.