Radiation testing on the dedicated four quadrant photodiodes specifically produced for the BiSon64 sunsensors is progressing nicely with very good results.
On 26th of November 2014 the preliminary results where presented at the CNES radiation workshop in Toulouse.
Even after 560krad of Co-60 radiation no measureable degradation was found on the quantum efficiency and only a marginal increase in darkcurrent was noted.
Although the tests will continue until the final goal of 1Mrad is reached, the measurements already show that the diodes used are very radiation tolerant and the Bison 64 sunsensors are therefore suited for even the most demanding applications.
Earlier test up to 10^16 1MeV electrons already showed good radiation tolerance, but this is now confirmed for total dose.
It should be noted that the test where performed on non protected diodes (no cover glass mounted) and the Bison 64 sunsensors provide approximately 1mm equivalent shielding in the front (650um sapphire) and 3mm aluminium on the other sides, thus rendering the sensors suitable for long duration GEO or MEO missions.
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