Detector

The reset level, i.e. the count level of the pre-integration readout of the array, is supposed to be stable. When commissioning the array, it was adjusted to an optimal level, i.e. a level that maximises the dynamical range and minimises bad pixels, by setting the dc-offset voltages. Over the years we have experienced various jumps in this level, needing a re-adjustment of the voltages each time.

Monitoring the reset level in each quadrant every hour over a period of 10 days gave an approximate linear relation, with the count level increasing by 750 ADU per 1 degree increase of the detector temperature. During this monitoring no jumps were detected. On the assumption that past changes in reset-level were caused by differences in detector temperature a level was select where normal temperature variations of the detector would not cause the reset level to go so low that the count levels could go below zero. However, a few months later the count level had jumped off this relation by $>$ 1000 ADU and the reset level had to be adjusted again. Further investigations are needed if there is something else which causes changes in the reset level (e.g., power-cycling the controller). A script is being made to monitor the reset value doing some basic statistics on dark images produced as part of regular observing, recording the results in a database for analysis.

A new, fixed data transmission fiber for the NOTCam detector controller was installed. This makes mounting and dismounting the instrument easier, faster and safer for the fiber. Additionally, NOTCam data can be obtained while the instrument is not mounted, which makes fault finding and offline diagnostics and testing easier.