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April 18, 2013 FDC meeting


  1. Production Construction Tracking (Dave)
    • Third package status
  2. Installation (Lubomir, Bill)
    • FDC installation document
    • Practicing at Blue Crab
  3. Engineering (Bill)
    • Cooling system tests
  4. Electronics (Chris, Nick)
  5. Full electronics tests FDC E-log
  6. Other


Participants: Eugene, Fernando, Bill, Dave, Chris, Nick, Simon, and Lubomir.


- Dave for the spare package: Just one wire frame remains to be deadened. We will start the installation of the first two spare cells next week. The plan is to install the last two cells with thicker spacer rings (just temporary to test the cluster counting technique). Therefore we need longer treaded rods, later they will be replaced with standard ones. As for the metal pins we can use the standard (short) ones: it will affect only the top cathode that can be centered with pins from the top. Eventually, we want to use He/Isobutane pre-mixed gas for the tests only with the top two cells and then we have to deal with number of issues: safety (flammability), permeability through mylar (Kapton is much better) and we may have to cover the end windows by an additional Kapton foil, but this will come later.

- Package #3 status: Cell #6 was tested successfully: all channels working and kept HV for 4 days without trips. All subsystems were restored: grounding, HV connections, also the strong-back was installed. Today we finished replacing the cooling loops; now the splittings are as in the other other packages. What remains to be done is the installation of the cooling manifolds and then the package can be moved to EEL126 for testing with the full electronics.


- We started collecting the information in a document (linked above) describing the FDC installation. We discussed what are the minimum requirement for the electronics to start the installation and testing of the FDC while it's outside of the magnet. First we discussed if it's possible to lay the cables in a proper way without connecting them to the electronics. Since at least the cable guides will be installed on the racks, this is possible, but then inserting the crates (full of modules) in between the cables will be tricky. At the end, for the testing we will need the modules. This procedure is much more feasible if the crates are already installed in the racks and we are adding modules as we go with the tests. In the moment according to the plan, the modules will be tested in the crates and then the crates together with the modules will be installed in the racks, but Fernando says it's possible first to install the crates only. Therefore, the most likely scenario (in case of delays with the electronics) will be to have the crates installed in the racks in advance. When we start cabling we will use the same set of modules for all the packages moving them from crate to crate.

- For the FDC tests outside of the magnet we will have to install scintillators at the top and bottom of the installation cart for cosmics trigger (Bill will work on the supporting frames). Given the delay with the fADC125 Fernando thinks it's not likely to be able to make self-triggering from the fADCs, so we should relay only on external trigger.

- We will have to leave Blue Crab in August and most likely FDC has to be stored somewhere before the installation starts in the Hall. We discussed different options: somewhere in the Hall, ESB, but the best would be to store it in the EEL126, it needs ~5 x 8 feet space.

- Practicing at Blue Crab with the cables: Dave installed wheels on the two installation carts that will be used for the tests, and made space for them near the clean room. Casey installed the mesh (top half) on the cart; it may need additional support (bearings) in the middle and Bill will look into that. It is good to have a template (made out of wood for example) to measure the thickness of the cable bundles around the mesh. The mock-up will be connected firmly to the cart just to hold the cables (we don't have enough holding brackets to user bearings).


- Bill: we will do the testing of the cooling system only with the set-up in the EEL126; no more tests at Blue Crab. The set-up in 126 has the same fittings, manifolds etc. To make sure the output pressure from the water chiller is low enough for the SMC chiller, there will be a bypass with a valve. The plan is to do the test on Monday.


- Fernando: by the end of next week we will have 34 fADC125 available. Now the communication with the company producing the fADCs is much better. The plan for the mass production is to have 45 units beginning of May and then receiving 45 each two weeks till the end of June. The production of the 54 F1TDC(V3) is finished, 43 will go to UMass for testing. By the end of May we will have all the TDCs here at JLab.

Full electronics tests

- The third package will be ready for moving to 126 by the beginning of next week. Will have 30 fADC125 by the end of next week. Will need 132 signal cables that we decided to label with the original labels, and 33 LV cables (not labeled); all this we will get from Nick. After testing the chiller at the beginning of the next week we can directly hook it up to the manifolds of the package. In summary: we will have all the infrastructure needed for the test by the end of next week, so we should plan moving the package to 126 by that time.