Revision as of 16:24, 12 July 2013

July 11, 2013 FDC meeting

Agenda

Production
- Final package assembly [1], [2], [3],[4], [5], [6] [7],(Bill, Dave)
Engineering (Bill)
Electronics (Chris, Nick)
Full electronics test FDC E-log (Beni)
- Pre-amp contact issues (Vlad)
Thick cell results [8],[9],[10], [11](Lubomir, Vlad)
Other

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 == Production ==
-- Final package installation (see the pictures linked above): First, Casey found a tiny hole in a cooling tube and he successfully fixed it with solder. We tried to check the cooling system for leakages using CO2 at 100psi, but the leak detector was not sensitive at all to CO2 even when you have obvious leakage. The first two packages were put on the installation cart and the spacer between them installed. The spacer fits tightly on the gusset ring and it was especially difficult to insert it in the second package. For the next spacer Bill proposed to make several holes, so that one can pull and make the circular shape at the end of the spacer in order to insert it into the gusset. We also had to do several cuts at the end to make space for the fiducial holders. Finally, it turned out there was a gap at the top between the spacer and the gusset ring, meaning the two packages were not exactly parallel. Bill tried to use the adjustment on the holding brackets to fix the problem, but it didn't work. Therefore, we inserted an aluminum threaded rod on the top (see last picture), to tighten the two packages together and the gap was fixed. It is possible by this we may have introduce some frame deformation, therefore Bill suggested to survey the packages after the final assembly at Blue Crab to make sure the packages are parallel and there's no deformation.
+- Final package installation (see the pictures linked above): First, Casey found a tiny hole in a cooling tube and he successfully fixed it with solder. We tried to check the cooling system for leakages using CO2 at 100psi, but the leak detector was not sensitive at all to CO2 even when you have obvious leakage. The first two packages were put on the installation cart and the spacer between them installed. The spacer fits tightly on the gusset ring and it was especially difficult to insert it in the second package. For the next spacer Bill proposed to make several holes, so that one can pull and make the circular shape at the end of the spacer in order to insert it into the gusset. We also had to do several cuts at the end to make space for the fiducial holders. Finally, it turned out there was a gap at the top between the spacer and the gusset ring, meaning the two packages were not exactly parallel. Bill tried to use the adjustment on the holding brackets to fix the problem, but it didn't work. Therefore, we inserted an aluminum threaded rod (in addition to the three fiberglass rods) on the top (see last picture), to tighten the two packages together and the gap was fixed. It is possible by this we may have introduce some frame deformation, therefore Bill suggested to survey the packages after the final assembly at Blue Crab to make sure the packages are parallel and there's no deformation.
-- We discussed what else is needed to finish the package installation. We will install plastic manifolds for the gas (instead of the aluminum ones that we have now), and will make also the connections between the cooling manifolds. Important question about the grounding connections. One of the results of the test with the full electronics is that we don't need additional grounding of the wire and cathode frames. According some experts, the connection of the detector to the Hall ground is needed only for safety. In 126 there's no such connection and the noise is low.
 == Engineering ==
-- Bill explained how to install the trigger scintillators on the FDC installation cart as shown in the 3D models above.
+- We discussed what else is needed to finish the package installation. We will install plastic manifolds for the gas (instead of the aluminum ones that we have now), and will make also the connections between the cooling manifolds. Important question about the grounding connections. One of the results of the test with the full electronics is that we don't need additional grounding of the wire and cathode frames. According some experts, the connection of the detector to the Hall ground is needed only for safety. In 126 there's no such connection and the noise is low. Therefore, we can have one ground cable for all the packages and it doesn't have to be thick.
-- We discussed the plan for the coming two months: finish with the spacers (end of this week) and the installation of the manifolds (next week) ; wait for the fiducial holders (end of next week) and then start installation of packages #1 and #2 on the cart with a spacer in between. After the third package is back from testing continue with the installation of packages #3 and #4; install the fiducials; make the gas connections between the packages (Bill still needs to find the right manifolds for the gas). At about middle of July, after all four packages are connected move them outside of the clean room and start practicing with the mock-up, connecting with cables one quadrant. Then, beginning of August move the packages to 126 and do the tests with the HV.
+- We discussed if we can use 1/4" tubes for the gas inside the solenoid. These tube will fit in the gas manifold. Outside tubes are 1/4".
-- At the same time we should start moving the equipment out of Blue Crab. According to Dave Tim is working to find some space for us in the TDEF building. Eugene: Rolf Ent stated that physics wants to keep the clean room. There are rumors that Hall C wants to disassemble (Walter is coordinating this) it and store it somewhere for later use, but nothing official. In any case we would like to have the right to use some area of the clean room if we need to do something on the FDC.
 == Electronics ==
-- Chris and Nick will collect all the signal cables for each package together: some of the cables are with Tom, that's why the cables at Blue Crab to be used for the mock-up are mixed.
+- Nick will check how many spare pre-amps we have to be used with the new F1TDCs with the spare package.
-- We may need contact cleaner for fixing the cathode pre-amp contacts; Chris will look for such cleaner.
 == Full electronics tests ==
-- Now the whole package is equipped with electronics and all the cables connected.
+-
-- Beni showed results of the 4 cell tests. In the  E-log entry 112 most of the pictures show the wire position as reconstructed by the strips. Interestingly, the width of the wire varies with the position in the chamber. It is small in the middle, then getting wider, then again small at the periphery. People suggested different explanations, but all this requires more studies, like plots of the widths along one strip, increasing the high voltage to see if the effect remains with higher signal and better strip resolution. Such variations resemble the variations we had of the charge from the strips due to frame deformation, but this is unlikely (Bill) since we have a strong-back now. Other than that, the noise on the strips and wires is as low as it was in the previous test of the packages partially equipped with electronics. Several cathode channel still require "fixing" by re-seating the pre-amps and eventually bending the cooling tubes.
-- Plans: after fixing all the channels we would like to take data also at different high voltages; expect to be ready with the tests by July 8th in which week we want to move the package to Blue Crab. There will be no time now to test the new F1TDCs, since this will require new crate and with a ROC and TI, and also development of the firmware and software. Rather than that, we decided to test the new F1TDCs with the spare package that will be moved to 126 at the same week of July 8th.
 == Other ==

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Revision as of 16:24, 12 July 2013

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