Detector controller

Observes noted that when using binning with ALFOSC you get additional noise in the form of vertical lines. It was found that the vertical strips seen in xbinned images is due to the lose of synchronisation of the controller power supply with the pixel readout timing. When you do binning in X the pixel time increases so giving a none integer period for the PSU to synchronise. For xbin 2 reducing the 'tsam' from 172 clock to 136 clock returns the synchronisation, and no strips are seen. The shorter sample time does increase the noise by $\sim$1 ADU (0.3 e-) compared with no binning.

The Dewar Interface Board (DIB) in the CCD3 controller failed again with identical symptoms as before, a bias level of $\sim$9100 ADU and no signal from amplifier A and a very high level $\sim$700k ADU from amplifier B. The board was replaced and two new boards were requested (and received) from NBI, Copenhagen, Denmark.