Detector

To correct the design error which causes the varying `dark-current', a plan for the electronics upgrade has been made on the basis of the information we have from Preben Nørregaard (CUO) regarding a new printed-circuit-board to be installed and tested in NOTCam. This work will start the 21$^{st}$ November 2007. We will install and commission the new Science Grade Array as soon as the array electronics has been modified, tested, and found to improve the dark current. This is preliminarily scheduled for early December.

Recently, interference pattern have intermittently been seen in low background images. It is similar in appearance to the pick-up noise problem we used to have before 2003. However, the read-noise on the detector is not affected. It appears now and then, and when it is visible the peak-to-peak amplitude is at most 5 ADUs, i.e., much lower than the typical 20 ADU we had before. Some tests were made to localise the source of the noise, but without success.