Speaker
Description
The CIS115 is a Teledyne-e2v CMOS image sensor with 1504 x 2000 pixels of 7 µm pitch. It has a high optical quantum efficiency owing to a multi-layer anti-reflective coating and its back-side illuminated construction, and low dark current due to its pinned photodiode 4T pixel architecture. The sensor operates in rolling shutter mode with a frame rate of up to 7.5 fps (if using the whole array), and has a low readout noise of ~5 electrons rms.
The CIS115 has been selected for use within the JANUS instrument, which is a high resolution camera due to launch on board ESA’s JUpiter Icy moons Explorer (JUICE) spacecraft in 2022. After an interplanetary transit time of over 7 years, JUICE will spend just under 4 years touring the Jovian system, studying three of the Galilean moons in particular: Ganymede, Callisto and Europa. During this latter part of the mission, the spacecraft and hence the CIS115 sensor will be subjected to the significant levels of trapped radiation surrounding Jupiter.
Proton and gamma irradiation campaigns have therefore been undertaken in order to evaluate both non ionising and ionising dose effects on the CIS115’s performance, up to 200 krad(Si). Characterisations were carried out at expected mission operating temperatures (35±10 °C) both prior to and post-irradiation. The degradation in imager characteristics, particularly the dark current and image lag, will be discussed relative to the mechanisms of radiation damage. Models of these mechanisms are then tuned with the experimental data to present the expected performance of the CIS115 during the JUICE mission lifetime.
