Date: Wed, 10 Oct 2001 15:01:41 -0500 From: Bob Wagner To: Karen Kephart , David_Erickson , Ken Schultz Cc: mukherjee@fnal.gov, Morris Binkley , ambrose@fnal.gov Subject: COT work during October shutdown HI, I'm sorry about the delay in organizing COT work for the October shutdown, but we are still working on a list of fixes. The earliest possible time for COT work to start is next Tuesday, the 16th, after the baggies are taken off the endplates. As usual, we are competing with Silicon detector projects, and no detailed work schedule is yet available. My feeling is that it would be best to start support from technicians for COT access work no earlier than Wednesday the 17th. This will give physicists a chance to do some preliminary diagnostics of electronics problems before attempting more detailed diagnostics and fixes with technicians. All of the "trip fixes" performed during the September access were successful. These fixes involved removing the HV daughterboard, modifying the board to disable the tripping wire, and replacing the board. We need to do this in two more spots early in the access, so it would be good if Wojciech were available for about 4 hours some time next week to re-install the boards. Subject to the results of some preliminary diagnostics, we are presently planning on breaking the gas seal and examining a cell with 5 disabled wires in SL4. I was hoping Ken would be available to either break free the ASD motherboard or give instructions. Wojciech or Michelle will likely be needed to help fix the problems, since they have experience with all aspects of handling the wire planes. If necessary, we will move all or part of the stringing engine over from Lab 6 to help with the repair. We will stop short of actually replacing a plane, but the engines could be used to move the endboards clear of the endplate slot for examinination and repairs (a much less critical task for the engines). If we decide to break the gas seal, I hope we can do it late next week. This would give us time to set up the stringing engine if necessary. There will be additional work on fixing electronics channels and minimizing noise which can also start next week. There will be several days of technician time needed to work on these problems, but not all in one chunk. Karen said earlier that Michelle would not be regularly available during the shutdown, but that both Ines and Wanda would be able to help with this. Kourosh also has considerable experience with these repairs. Aseet has a bench-top electonics assembly project would could start next Tuesday, and he thinks Ines and Wanda would be perfect for this. If this was done at B0, they would then be immediately available for work on the chamber when we're ready. I still wish to put thermal insulation around accesible parts of the COT endplate ID using the aluminum bubble wrap (a job for Kourosh). This will have to wait until it is decided how to raise the SVX by 4 mm. If it is decided that the COT needs to be raised to accomplish this, Aseet would like Ken to take a look at particularly the SUVA lines and how to possibly generate more clearance for their movement inside the cable slots. Please let me know if the people mentioned above are available. Since the access is reasonably long, we can shuffle work times to best suit those involved at some level. Thanks, Bob