09.20 CARME chamber at atmospheric pressure as expected.

      Will open CARME chamber and inspect COF600 wire seal for similar (or other) issues to the seal removed yesterday. One possibility is that the COF600 flange 
surfaces/structures are misaligned and part of seal is 'escaping' the seal zone. Given the flanges close easily the misalignment would have to be small.

13.30 Observations

      The bolts on the upstream feet of the far detector chamber are all loose and have probably been so for some time

      Based on measurements with calipers and the insertion of shims into the *radial* gap between COF600 flange surfaces the COF600 flanges may be misaligned and rotated 
transversely by a fraction of a millimeter. The challenge is that the chamber is not designed for fine transverse adjustments and it is not easy to measure the changes.

      The Pfeiffer recommended procedure for closing COF seals is to start tightening bolts *diametrically* and then to tighten sequentially

https://www.pfeiffer-vacuum.com/en/know-how/mechanical-components-in-vacuum/connections/detachable-flange-connections/cof-flanges/

     The plan

     Adjust position of far detector chamber and secure upstream feet bolts

     Close COF600 flange using Pfeiffer recommended procedure

     Today is Friday so it will probably be Monday before we can pump the CARME chamber

13.50 Another view

     Grosmontage also inspected the COF600 seal this afternoon. They said that it was important that the seal should be installed under tension to ensure that it remained 
in position as the flanges were closed and the bolts begin to be tightened. They think the seals are a little too large in circumference but that they can shorten one on 
Monday morning.