Vacuum & Cooling

As part of opening NOTCam, several parts in the filling and venting tubes were polished and refitted, and also several O-rings were changed. This to reduce the recurrent problem when filling the dewar with LN$_2$ if NOTCam stays off the telescope for a longer time.

The flexible steel hoses that carry helium gas in the closed-loop PTR cooler are exposed to continuous stress. A new, more flexible hose was bought to replace the one that had to be repaired the most (the supply hose). Since then there has been a much lesser need of re-filling the system with Helium.