Difference between revisions of "Minutes-10-13-2011"

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# Testing set-up at EEL126 (Beni)  
 
# Testing set-up at EEL126 (Beni)  
 
# Other
 
# Other
 
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= Minutes =
 
= Minutes =
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== Production ==
 
== Production ==
  
- Dave: First package is was fully assembled as of yesterday. Now working on the second package. The first cathode (type-3) is ready. Working also at another two cathodes and two end windows together in order to save conductive epoxy. There was a problem with the first wire frame when replacing the HV caps. The first replacement resulted in somewhat elevated leakage currents and it was decided to replace them once more. After the caps were removed it turned out many many of their pads delaminated.    
+
- Dave: First package is was fully assembled as of yesterday. Now working on the second package. The first cathode (type-3) is ready. Working also at another two cathodes and two end windows together in order to save conductive epoxy. There was a problem with the first wire frame when replacing the HV caps. The first replacement resulted in somewhat elevated leakage currents and it was decided to replace them once more. After the caps were removed it turned out many many of their pads delaminated. We will continue the production with the next wire frame that was already laminated while trying to fix this one. Bill says somebody from the electronics group already fixed delaminated traces on a frame before.
  
- We have four cells in the first package as of Tuesday evening. Finally we fixed the gas leak in the second cell (at the third attempt): a bubble in the epoxy inside  the chamber (that seals the gap between the solid part of the g10 and the PCBs) made a path for the gas to leak. A missing part of the trace  on a signal wire in the third cell was fixed by Dave. All the channels of all the wire planes and cathodes were checked with a generator prior the installation. We had to replace the top spacer ring because it turned out after the first installation that the gas openings were not drilled there. Bill proposed to check the flow trough the gas openings relatively, using a rotarmeter with a fixed impedance.  
+
- Lubomir: Full first package running with gas since Wednesday evening. Leakage very low: bubbling at 35 ccpm. Will start testing today evening or on Friday. Valdimir tested the five cells before and found one problem: on one of the newly installed cathodes (type-1) on the top of cell#4, one flex delaminated completely from the cathode. All the conductive tape was on the cathode and nothing on the flex which is not normally what we see; in several cases when we had to remove the rigid-flex from the cathode pieces of conductive tape remain on both sides. The flex was glued again and the cathode installed at the same place. Now with all the six cells in the package Vladimir will test all the planes above and including this cathode since all these were either re-installed or never tested.
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- Lubomir: we could not have the stack with the four cells bubbling when using a many-fold at the output. That's why we separated the outputs and put additional impedance at the output tubings: 2m long thin tubes. That resulted in almost equal pressure in all the chambers of ~30Pa at 40 ccpm total gas flow. The pressure inside the chamber was different by up to 10Pa when using the many-fold. No explanation of this effect, but just adding thin tubes at the output is a simple solution; at the same time it will prevent over-pressure.
 
 
- Vladimir started already testing the package: yesterday he checked the third cell, today he was working on the second cell. The new fourth cells is not conditioned yet: we are at +1500/-500V now. Finally we have the 55Fe source (from RadCon) at Blue Crab and not only the testing is much faster but one can compare the amplitudes at the different channels.
 
 
 
 
== Engineering ==
 
== Engineering ==
  

Revision as of 12:01, 14 October 2011

October 13, 2011 FDC meeting

Agenda

  1. Production Construction Tracking (Dave)
    • Status
    • First package tests (Lubomir)
  2. Engineering update (Bill)
  3. Electronics update (Chris)
  4. Testing set-up at EEL126 (Beni)
  5. Other

Minutes

Participants: Eugene, Bill, Dave, Chris, Simon, Beni, Vladimir, Mark, and Lubomir.

Production

- Dave: First package is was fully assembled as of yesterday. Now working on the second package. The first cathode (type-3) is ready. Working also at another two cathodes and two end windows together in order to save conductive epoxy. There was a problem with the first wire frame when replacing the HV caps. The first replacement resulted in somewhat elevated leakage currents and it was decided to replace them once more. After the caps were removed it turned out many many of their pads delaminated. We will continue the production with the next wire frame that was already laminated while trying to fix this one. Bill says somebody from the electronics group already fixed delaminated traces on a frame before.

- Lubomir: Full first package running with gas since Wednesday evening. Leakage very low: bubbling at 35 ccpm. Will start testing today evening or on Friday. Valdimir tested the five cells before and found one problem: on one of the newly installed cathodes (type-1) on the top of cell#4, one flex delaminated completely from the cathode. All the conductive tape was on the cathode and nothing on the flex which is not normally what we see; in several cases when we had to remove the rigid-flex from the cathode pieces of conductive tape remain on both sides. The flex was glued again and the cathode installed at the same place. Now with all the six cells in the package Vladimir will test all the planes above and including this cathode since all these were either re-installed or never tested.