Difference between revisions of "Minutes-4-25-2013"

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= Agenda =
 
= Agenda =
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# Production [http://www.jlab.org/Hall-D/detector/fdc/production/FDC_Construction_April_25_2013.xlsx Construction Tracking] (Dave)
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# Production [http://www.jlab.org/Hall-D/detector/fdc/production/FDC_Construction_April_25_2013.xlsx Construction Tracking]
 
#* Third package status
 
#* Third package status
 
#* Spare package
 
#* Spare package
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== Production ==
 
== Production ==
  
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- 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.      
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- Third package: Casey installed the manifolds without tightening the compression fittings, but as it turned out from the cooling system tests (see below), we have to check the manifolds with high pressure before finishing the installation.
  
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- 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.
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- Spare package installation: installation table is ready, Casey made the threaded rods that are longer by 6cm for this package. Next week (after we are done with the third package) we will start putting O-rings on two spacer rings and  one type-1 cathode. The plan is to install two cells at once. The last two cells will be with the two thicker spacer rings, to be used to test the cluster counting technique. It turned out it that we can use the standard gas (40/60) for these studies instead of the Helium mixture. Due to the lower drift velocity with the standard gas one can get a good cluster separation, just we will have up to ~20 microsec drift time, compared to ~7 microsec with the Helium gas.
  
 
== Installation ==
 
== Installation ==
  
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- 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.
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- 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.  
 
- 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.  

Revision as of 15:56, 25 April 2013

April 25, 2013 FDC meeting

Agenda

  1. Production Construction Tracking
    • Third package status
    • Spare package
  2. Corrosion tests at MePhi: results, [1], [2], [3], [4], [5], [6], [7]
    • Discoloration in the bottom cathode of package #3 [8], [9], [10], [11]
  3. Installation (Lubomir, Bill)
    • FDC installation document
    • Practicing at Blue Crab
  4. Engineering (Bill)
  5. Electronics (Chris, Nick)
  6. Full electronics tests FDC E-log (Beni)
  7. Other


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