Feedthrough Meeting 16/01/98 present: P. Birney, M. Fincke-Keeler, T. Hodges, A. Humphrey, R. Keeler, R. Langstaff, M. Lefebvre, P. Poffenberger - Warm welcome to Alisa! - Schedule Update Michel pointed out that, apart from a small slip of a few weeks, the official schedule for the project remains as before. Richard pointed out that it is important for us to know the real schedule (especially in the light of the pigtail problems and of the latest endcap cryostat change), as this affects cost and manpower usage. Michel adds that this is a constant worry, and that pressure to have the official schedule updated at CERN is maintained. - Status of Pin Carrier Design and Order Roy reported that he received Jason's pin carrier drawings on Dec 22nd. A few improvements were proposed on January 2nd. Dave Rahm indicates that the pin carriers are to be ordered the week of the 12-16 of January 98. Michel reminds that we have ordered for Victoria 20 pin carriers from Glasseal and 10 pin carriers from PCT. The delivery time is expected to be 14-16 weeks. - Design and Bellows Issues Roy Reports that discussions on the bellows to flange interface has been going on for some time with Jason and Dave. Roy is to accompany Dave mid February to a visit of BOA, the bellows company in Atlanta. Roy remarks that knowledge of the bellows is needed before finalizing the feedthrough assembly drawings. Coordination with D. Laporte is required, since they claim that they need to have drawings of the feedthrough assembly soon to pursue the endcap cryostat design. Pierre Pailler has communicated with a French bellows manufacturer. Details were communicated to Roy. We agreed that we were to wait after the visit to BOA before considering action on this front. Bellows must be tested at 3.2 bar. Michel reported that BNL is currently preparing a test setup. We could provide BNL with the appropriate hardware to test the bellows in an endcap environment (skirt). Since the test for the endcap does not involve lateral sheer stress, we could perhaps perform the test hydraulically here in Victoria. Roy points out that the increase in radial space in the cryostat to allow automatic welding of the feedthrough units would result in a smaller fraction of the bellows covered by the cryostat skirt. Terry mentioned that we could request this skirt to be extended inwards to cover the bellows completely. Concerning the flange design, Terry reports that further FEA analysis shows that a change of warm flange thickness from 23 mm to 28 mm only has a marginal effect on the stress on the carrier web, but that this allows the pin carrier to be recessed in the flange. Dave Rahm still has to comment on this. - Status of Leak Test Setup Paul reported that the warm/pump side of the leak test setup is coming along nicely. The next steps include commissioning the RGA and the pressure gauges. The possibility of an additional PC dedicated to the RGA (and possibly the pressure gauge) was entertained. Michel to look into it. Michel points out that the initial plan was to use the same PC as so far used in the ATLAS lab. But all agree to Richard's comment that we should really have a PC for control and a different PC for data acquisition. - Refrigerator Design Update Alisa and Paul reported on the design of the temperature controlled refrigerator. Cooling is to be provided by our two state cryopump, or by a LN2 bath. The first and second stage should be shorted to avoid temperature difference. It was agreed to order the material needed to start the construction. It was argued that we should first built it without an inner can, and see if the temperature is homogeneous in the pin carrier space volume. Pof to look into the cost of a multichannel temperature controller. - Model After some discussion, it was agreed to go ahead as soon as possible with the manufacture of the (metal) model. Material is already here. Paul to obtain the appropriate drawings from Roy and to coordinate with the machine shop. Margret reported on the mock vacuum cable production. The concept is now quite advanced, and allows two screws per fake connector, as in a real assembly. Materials for the fake strips have been investigated, and solutions exists. Fake strips to be cut quickly using a saw. Terry points out that a wood model could also be useful. It was agreed that the weight and handling issue is important. Furthermore the metal is already in hand. We agreed to go ahead with the metal model for now. - Assembly Jigs Paul reminded us that it would be very useful to decide on the assembly order to finalize the assembly jig design, especially with regards to the pigtail bucket. It was agreed that this would be investigated with the model. Margret, Paul and Michel to pursue the development of a assembly procedure step list. Paul to push the design as far as possible without a decision on the exact assembly procedure. - Vacuum Cables Status Margret reported that Ernie is to contact Strataflex concerning the delivery date of the ordered strips, and concerning the connector design to be tried by Strataflex. The "bright tin plating" is now confirmed to be of a type adequate for our cryogenic usage. Margret has made a first attempt at Daisy-chaining the strips to allow a fast strip testing using the network analyzer. Investigations being pursued. Margret pointed out that we still do not have an answer concerning the possible failure mode of the preamplifiers that could result in a large current down a signal stripline. Terry has updated his calculations of the stripline temperature for the low voltage stripline, with the agreed dimensions: 0.070 mm trace thickness 0.400 mm trace width 0.400 mm inter trace space 0.050 mm kapton thickness Michel to include Terry's results in the FEA LaTeX book, and to present his results at the next LAr week. - Electric Test Setup As mentioned above, Margret is investigating the strip cable testing using the network analyzer. Contrary to our previous decision, we have now decided to put on hold the DC testbox order as this was not deemed urgent. - Computer Order Status The PC for Alisa is on its way [already here?]. The ATLAS PC count is then the following: borg: Server PC (on Michael's desk). (MIG) eddie: PC reserved for ATLAS lab (helping Roy just now). (MIG) ?: PC for CAD (for Alisa). (MIG) ?: Perhaps another PC for the ATLAS lab (MIG) ?: Soon a portable PC for management (Michel) (MIG) higgs: PC on Michel's desk (Operating) There are also other non ATLAS-paid PC around: trilab2: Paul's PC ?: Roy's PC (on order) hep: Richard's PC - Documentation Michel mentioned that we need to produce a set of documents for the feedthrough projects. A list of proposed notes and proposed editors has been distributed separately. We need to agree, with our BNL and Orsay colleagues, on the note editors by the end of next week. Comments appreciated. - Next LAr week The next LAr week at CERN is scheduled from Monday Jan 26th to Friday Jan 30th. Margret, Roy and Michel will attend. Richard noted that the LAr week meeting list did not include the Monday feedthrough meeting. Michel to point this out to Pierre Pailler and Daniel Fournier. [Done]. - ATLAS meetings and other important dates - Jan 26 - Jan 30 : LAr week - Feb 15 - Feb 21 : Lake Louise Winter Institute - Mar 02 - Mar 06 : ATLAS week - Mar 09 - Mar 13 : LAr week - Mar 29 - Apr 04 : ATLAS Physics workshop, Grenoble - May 04 - May 10 : LAr week - Jun 08 - Jun 12 : ATLAS week - Jul 06 - Jul 10 : LAr week - Jul 23 - Jul 29 : ICHEP98 "Rochester Conference", TRIUMF - Sep 04 - Sep 18 : ATLAS week - Sep 21 - Sep 26 : LAr week - Nov 12 - Nov 18 : LAr week - Nov 16 - Nov 20 : ATLAS week