We present the results after 2.5 years in or-bit of Total Ionizing Dose (TID) measurements done using Metal Oxide Semiconductor (MOS) dosimeters on the MeMOSat board. The MeMOSat board was launched on July 19th 2014 at the BugSat-1 "Tita" microsatellite developed by Satellogic to stay at LEO. We used as dosimeters p-channel Commercial Off The Shelf (COTS) MOS transistors with gate oxides of 250~nm. Before launch, a subset of transistors with similar drain current to voltage (I-V)curves where selected from a group of 100 devices. The temperature dependence of the (I-V) curves was studied to find the minimum temperature coefficient biasing point. Then, a calibration subgroup of sensors was irradiated using a 60Co gamma source to study their response to TID, showing responsivities of ∼75~mV/krad when the sensors are irradiated without gate bias. Also, the post irradiation response of the sensors was monitored, in order to include a correction for low dose rate irradiations, yielding 30~mV/krad. A biasing and reading circuit was developed in order to allow the reading of up to 4 sensors.The threshold voltage was monitored during different periods of the mission. After 2.5 years in orbit,the threshold voltage of the sensor mounted on the MeMOSat Board had a VT shift of approximately 35~mV corresponds to a dose of 1.2~krads.
@article{arxiv.2007.00143,
title = {COTS MOS Dosimetry on the MeMOSat Board, Results After 2.5 Years in Orbit},
author = {José Lipovetzky and Mariano Garcia-Inza and Macarena Rodríguez Cañete and Gabriel Redin and Sebastián Carbonetto and Martín Echarri and Federico Golmar and Fernando Gomez Marlasca and Mariano Barella and Gabriel A. Sanca and Pablo Levy and Adrián Faigón},
journal= {arXiv preprint arXiv:2007.00143},
year = {2020}
}