Difference between revisions of "Minutes-2-9-2012"

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# Other
 
# Other
  
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= Minutes =
 
= Minutes =
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- Dave: wire boards #20 and #21 waiting for electroplating. #22 will be populated soon by Chris. The problem on #23 was fixed (see pictures attached):
 
- Dave: wire boards #20 and #21 waiting for electroplating. #22 will be populated soon by Chris. The problem on #23 was fixed (see pictures attached):
the signal trace on wire #96 had short to ground on the side of the PCB close to the via. The frame was drilled on the back side through the G10 and Rohacell to reach the board, the trace was disconne signal trace (#96) has short to ground most likely in the via or on the trace on the back side of the board. The plan is first to drill the via and confirm the problem is there. Then we will make an opening in the frame to access the trace on the back side of the board, fortunately there's Rohacell on the back of the via, not solid G10. Then we will solder insulated wire to make the connection. Cathode #33 was glued to the frame with some offset of ~3mm at most. One frame hole covers a trace on the connector; it can be fixed in principal but also the offset is not acceptable (Simon). So we have enough spare material to replace this cathode and will use it only if needed. Wire frame #13 (with the capacitor traces de-laminated) was inspected by EEFAB people. They said it can be fixed in two days, however later they claimed they need a $26K machine for that and want to share the costs; Dave will negotiate with them
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the signal trace on wire #96 had short to ground on the side of the PCB close to the via. The frame was drilled on the back side through the G10 and Rohacell to reach the board, the trace was disconnected before the via and insulated wire was used to make connection to the other side of the board through the via. Wire frame #13 was given to the EEFAB people for gluing the traces under the HV caps that de-laminated, but they have sent the board to an outside company. There they decided that the traces have enough strength and soldered the HV caps, all this without our knowledge! Fortunately, after replacing one cap with a solder ball on the back, the dark current is now low enough. The next step was to put epoxy on the caps since they are hanging now on the traces. For that, samples were made to test the dark current change. On one cap we had ~200nA with Scotch-weld and ~400nA with Epon one day after gluing across the cap. Therefor the decision was to put Scotch-weld only on the sides of the caps. Ten caps on the sides of the wire frame were already glued. After making sure the dark current is reasonable we will continue with the rest. Working also the cathodes for the third cell of the third package. 
  
- Another sample using the original electroplating recipe was made with the hope the surface will be smoother. Waiting for the microscope pictures from Olga to make a decision whether we can continue with the wire deadening: two wire planes ready and waiting for this decision.
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- Two more samples using the electroplating  
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- Second package was put in the rail frame. We discussed that one of the bearings must be fixed (no gap), right now both are loose, so has to be replaced later. Chris: pre-amps for four cells ready but ran out of screws then Cody has to test them. After that we will install them on the package together with the cooling tubes.
 
- Second package was put in the rail frame. We discussed that one of the bearings must be fixed (no gap), right now both are loose, so has to be replaced later. Chris: pre-amps for four cells ready but ran out of screws then Cody has to test them. After that we will install them on the package together with the cooling tubes.

Revision as of 16:43, 9 February 2012

February 9, 2012 FDC meeting

Agenda

  1. Production update Construction Tracking (Dave)
    • Third package status
    • Electroplating results
  2. First package testing FDC ELOG (Beni, Lubomir)
  3. Engineering update (Bill)
  4. Electronics update (Chris)
  5. Other


Minutes

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

Production

- Dave: wire boards #20 and #21 waiting for electroplating. #22 will be populated soon by Chris. The problem on #23 was fixed (see pictures attached): the signal trace on wire #96 had short to ground on the side of the PCB close to the via. The frame was drilled on the back side through the G10 and Rohacell to reach the board, the trace was disconnected before the via and insulated wire was used to make connection to the other side of the board through the via. Wire frame #13 was given to the EEFAB people for gluing the traces under the HV caps that de-laminated, but they have sent the board to an outside company. There they decided that the traces have enough strength and soldered the HV caps, all this without our knowledge! Fortunately, after replacing one cap with a solder ball on the back, the dark current is now low enough. The next step was to put epoxy on the caps since they are hanging now on the traces. For that, samples were made to test the dark current change. On one cap we had ~200nA with Scotch-weld and ~400nA with Epon one day after gluing across the cap. Therefor the decision was to put Scotch-weld only on the sides of the caps. Ten caps on the sides of the wire frame were already glued. After making sure the dark current is reasonable we will continue with the rest. Working also the cathodes for the third cell of the third package.

- Two more samples using the electroplating