ELOG CARME

AIDA GELINA BRIKEN nToF CRIB ISOLDE CIRCE nTOFCapture DESPEC DTAS EDI_PSA 179Ta CARME StellarModelling DCF K40

CARME

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Entry time:	Fri Apr 4 17:18:14 2025
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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. Encoding: HTML ELCode plain Suppress Email notification

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