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

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# Tests at EEL126 [https://halldweb1.jlab.org/elog-halld/FDC FDC E-log] (Beni)
 
# Tests at EEL126 [https://halldweb1.jlab.org/elog-halld/FDC FDC E-log] (Beni)
 
# Other
 
# Other
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= Minutes =
 
= Minutes =
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== Production ==
 
== Production ==
  
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- Dave: the last two wire frames populated by Chris. The only remaining operation is to deaden four wire planes. The extra spare cathode type-2 is tensioned, but the cards are not installed yet by purpose (for easy storage).
+
- Dave: will start wire deadening tomorrow; wire frames #2 and #3 will be the first to go with. In total 4 wire frames have to be deadened.  
  
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- Package #3 repair: last Friday we started testing the top cell (after we opened it once and removed a lint) and it was tripping again. On Monday we opened the package for a second time and looked more carefully: there were some small balls on two sense wires and a section of a field wire that looked suspicious. We tried to clean these places and closed the package, turned out again without success. Troubleshooting the problem is difficult because it appears from time to time once per several hours. The dark currents are very low, there's no constant noise  and we can't localize the problem. We decided to open the package tomorrow morning, put the wire frame on the stringing table at 90deg (Bill's idea) and scan the wires with the camera. We will clean if possible, or replace the bad wires and next week will give it another try. If it still doesn't work, we will put a spare wire frame (#28, it had higher dark (~350nA) current but was stable for weeks).
+
- Package #3 repair: we scanned all the wires of the HV sector #2 (on the wire frame of cell #6) using the camera of the motion station on the stringing table. There were three field wires with some stuff we could not clean. We disconnected these wires from the HV side, by un-soldering and cutting the end of the wire, but without success: the HV problem remained. Then we removed half of resistors at the HV side of the sense wires and the problem went away. Using this method we went down to 5 questionable wires, and at his moment Anatoly found a tip of a sense wire (~5mm) sticking out of the solder. After fixing this, the chamber now is holding HV already 10 hours. We will wait till tomorrow and then Casey will replace the three field wires, so the wire plane will be ready for installation by Monday.    
  
 
== Installation ==
 
== Installation ==
  
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- The last, "frozen" schedule moved the FDC installation just by a couple of days. Now the FDC insertion is in the middle of January 2014, dictated mainly by the electronics. Since the testing outside of the magnet should start much earlier we must be able to test the different packages connecting to the same electronics.  
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- Yesterday, there was a "FDC cable installation" meeting on which Rich Getz presented his new plan shown on the three pictures attached above.  
  
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- With Eugene, Bill, and Fernando together there were long discussions about the cabling. There was a concern (Lubomir) that with the current installation scheme, when the FDC is inserted one needs extra cable that is one cart long. In total we will need about 3 x 2.5 carts which might be close to 18m, the length of the signal cables. Bill will check that with the I-deas model. Fernando insisted that we have to keep the cables fixed to the racks at the downstream end and never un-bundle them. In this case the question is where to put the extra bundles that are 6-7m long after the insertion of the FDC: if possible somewhere at the front of the magnet??
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== Engineering ==
  
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- Installation of the cables from the two bottom quadrants will be difficult because of the small opening going to the bottom (below the platform) trays. Bill had an idea to elevate the racks so that the space below them will be accessible from the front and the cables can run there. This makes the cable installation much easier, but requires taller people to service the electronics. Other options: 1) disconnecting the cables from the electronics before FDC insertion and re-connecting them again after the insertion (Lubomir), but has to be done every time we take FDC out of the magnet. 2) Putting all the cables on the top side of the racks (Eugene), but the length might not be enough and it will be more difficult to work there.
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== Engineering ==
+
  
 
- Bill and Casey tested the cooling of package #4 that has the manifolds installed: first with CO2 at 100psi and then with Flurinert, pressured again with CO2. No significant leakage was found with CO2, but with Flurinert it was leaking like a sieve (Bill) however mostly at the temporary barb connections needed to do the test, while the compression connections didn't show obvious problems. It turned out the leakage detector we have is not very sensitive to Fluorinert. So, for the next test we need better fittings and leakage detector.   
 
- Bill and Casey tested the cooling of package #4 that has the manifolds installed: first with CO2 at 100psi and then with Flurinert, pressured again with CO2. No significant leakage was found with CO2, but with Flurinert it was leaking like a sieve (Bill) however mostly at the temporary barb connections needed to do the test, while the compression connections didn't show obvious problems. It turned out the leakage detector we have is not very sensitive to Fluorinert. So, for the next test we need better fittings and leakage detector.   

Revision as of 16:34, 4 April 2013

April 4, 2013 FDC meeting

Agenda

  1. Production Construction Tracking (Dave)
    • Package #3 repair
  2. Installation (Lubomir, Bill)
    • Cable installation: Rich's models [1], [2], [3]
    • Plans for practicing at Blue Crab
  3. Engineering (Bill)
    • Cooling system status [4]
  4. Electronics (Chris, Nick)
  5. Tests at EEL126 FDC E-log (Beni)
  6. Other

Minutes

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

Production

- Dave: will start wire deadening tomorrow; wire frames #2 and #3 will be the first to go with. In total 4 wire frames have to be deadened.

- Package #3 repair: we scanned all the wires of the HV sector #2 (on the wire frame of cell #6) using the camera of the motion station on the stringing table. There were three field wires with some stuff we could not clean. We disconnected these wires from the HV side, by un-soldering and cutting the end of the wire, but without success: the HV problem remained. Then we removed half of resistors at the HV side of the sense wires and the problem went away. Using this method we went down to 5 questionable wires, and at his moment Anatoly found a tip of a sense wire (~5mm) sticking out of the solder. After fixing this, the chamber now is holding HV already 10 hours. We will wait till tomorrow and then Casey will replace the three field wires, so the wire plane will be ready for installation by Monday.

Installation

- Yesterday, there was a "FDC cable installation" meeting on which Rich Getz presented his new plan shown on the three pictures attached above.

Engineering

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