L3CCDs for proton irradiation

Continuing the work carried out to investigate the effects of protons on the operational characteristics of L3CCDs, a batch of 100 CCD97s, plus a few control devices, have been delivered from e2v technologies to Brunel University. Low-Light-Level (L3) CCDs have been baselined for the RVS instrument on Gaia and proton irradiation of L3 devices allows for the characterisation of the effects of radiation damage.

To date, L3 proton irradiations have been conducted on CCD65 devices, irradiating initially to a 10 MeV equivalent proton fluence of 2.5 x 10⁹ protons cm^-2, then subsequently to a 10 MeV equivalent fluence of 2.1 x 10¹⁰ protons cm^-2, approximately 10 times the RVS 6 year expected mission fluence. In all cases the irradiated devices were operational after irradiation and behaved as expected, with dark current levels and bright pixel generation comparable to those in proton irradiated non-L3 devices.

The irradiation of 100 CCD97s will improve the radiation damage statistics further, defining confidence limits for the survivability of L3 devices in the space radiation environment for Gaia and other missions proposed in the future.

Photo courtesy of David Ryan Smith.

[Published: 31/01/2005]