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| − | Participants: Tom, Scott, Eugene, Tim, Slava, Mark, Dave, Chris, Nick, Vlad, Simon, Beni, and Lubomir. Many participants this time, some of them left after Tom's presentation. | + | Participants: Bill, Glen, Eugene, Chris, Nick, Simon, Vlad, Beni, and Lubomir |
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| − | == FDC installation and cable routing ==
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| − | - Tom went through the slides linked above showing the FDC in three positions and on separate slides only the cable routing for these positions. The cables are divided in four quadrants and bundled together between the mesh cylinder (that separates the cables from the CDC) and the electronics racks.
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| − | Left and right sides are symmetric. Two bundles run on the floor turn, below the platform, and go up through openings to the racks. The other two bundles will run over hangers attached to the racks and installation carts.
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| − | - The length of the bundles in the drawing is biggest for the initial position. While the FDC is being moved into the magnet, the top sections of the carts will be removed and the lower bundles will be lifted (there's enough slack) over the lower part of the carts. According to Tom this will be the most difficult part: the bundles have to be well supported to avoid deformation of the mesh cylinder. During this operation the bent position of the bundles will change all the time. Despite the stiffness of the bundle this will be possible (Tim, Tom). In the final position the length of the bundled section will be smallest, in reality the bundle length will not change, which means we have to find place for service loops. There will be additional loops of the individual cables either inside the bundles or close to the electronics.
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| | == Production == | | == Production == |
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| − | - Dave: Installation of the fourth package was completed on Monday. Today Vlad noticed that one cathode in the middle was positioned incorrectly (15deg off). We discussed if it is possible to lift the top three cells together, correct the cathode position and then put the three cells back. For that we pull down the installation pins (one by one) to the right position so that separate only the top three cells and then insert from the top additional pins to keep to top part together. After the meeting this operation was done successfully. Three of the pins we did like this, for the other three we pushed the top pins further down so that it was easier to insert the top part in the right place. | + | - Dave was absent but he updated the production tracking linked above: last two spare cathodes are almost ready. Spare wire frames: third wire frame (#6) is being tested already for a week, the current is very high (~1100nA) which doesn't surprise anybody since the caps were not replaced. Bill wanted to know if we have to order additional g10 frames. We have one spare frame now that will be used to replace wire frame #1. First we will try to fix #6, if it doesn't work we have to order g10 frames. The problem with #6 is that the caps are covered with Himiseal. Bill suggested, first, removing the caps (say on one HV sector) and then cleaning the Humiseal. Chirs: aceton cleans Humiseal very well (we can't use it inside the chamber!), but one can also use alcohol; have to soak the Humiseal first and after 5min start cleaning. We will try that. |
| − | We can use this technique to separate part of the package if we have to fix something there.
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| − | - Dave showed the scheme (linked above) for the package refurbishment. As we did with the third and fourth packages we will install and test them in two halves. Techs working on the last two spare cathodes and preparing the last two spare wire frames for testing. | + | - Started preparations of the first package (which is at Blue Crab) for refurbishment: HV cables were disconnected from the cables connected to the two HV connectors. Later we may have problems to reconnect them since the cables were cut to the proper length, we have to route them exactly in the same way. Copper tubes (together with the one part of the pre-amp brackets that is glued to the tube) and the pre-amps were removed from the package. |
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| − | - Chris will submit PR for four PCB sets. We need to build (so far) one wire frame and for that we have a spare laminated G10 frame. If more wire frames are needed we will have to order more G10 frames, as well. | + | - Fourth package tests: Vlad tested cell #4 which is OK. On cell #3 (with wire frame #28) the current was very high (~800-1000nA) and doesn't go down already four days, but never tripped: most likely the HV caps have problems. Other than that all the channels on #3 are fine. Vlad applied today HV on cell #2, the current was initially 500nA but then started going up. It turned out Anatoly doesn't have a record that he replaced the HV caps on #27. |
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| − | - Today the first package was moved back from EEL126 to Blue Crab for refurbishment. We are preparing for the installation of the subsystems on the third package. Will try to print the pre-amp labels from file and put them on the cards before the installation. | + | <!-- |
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| | == Engineering update == | | == Engineering update == |
