Krishna

The End Station VEA temperatures are currently locked to H0:FMC-EY_VEA_AVTEMP_DEGF, which is an average of various sensors mounted to the walls of the VEA. As has been discussed before, what we'd like to hold constant is the temperature of the suspensions or the vacuum chambers. The attached plot shows various temperature sensors (refer to Jeff's alog for calibration) in the VEA which all show a rising trend (the M0 has a negative temp coefficient), whereas the FMC average sensor shows a constant trend. The reason for this is it is getting colder outside, so the walls are cooler. Therefore to keep the walls at the same temperature, the inside has to get warmer.

Robert and others had noted this for the corner station earlier and I've been told that this was fixed at the corner station but not at the end stations. I would recommend fixing this problem for both the end-stations as well. One possible solution is to simply mount the FMC sensors on or closer to the vacuum chamber.