Cosmic ray dose monitoring using RadFET sensors of the Rosetta instruments SESAME and COSIMA

The resulting dose profiles show linear increases of the accumulated dose with time, mainly caused by galactic cosmic radiation, and the arrival of two solar particle events in 2005. The accumulated dose (in Silicon) during 3909 days in space from 2004-03-02 to 2014-11-14 was 3.2±0.6Gy in case of COSIMA and 1.9±0.4Gy for SESAME. The deviation of the two measurements is mainly due to the solar particle event in September 2005, which had a 5.3±1.0 times stronger impact on the COSIMA RadFET. Measured dose levels are one order of magnitude lower than those expected before launch for not being exceeded on the 90% confidence level, which is mainly due to the low solar activity during the mission so far.