Difference between revisions of "Minutes-8-18-2011"

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- Beginning with the wire frame #5, we started testing the HV caps before stringing. It requires some conditioning but few days were enough to test wire frame #5. Now we are having problems with wire frame #6. We identified so far 8 caps that need to be replaced. After the meeting we continued with the tests and we found another 4, so 12 in total. Anatoly, who removed the caps, mentioned that on 5 of these there were solder balls below the caps somewhere between the pads (see pictures linked above). The balls are actually flat (like coins). Therefore we suspect that they were there before the caps were un-soldered by Anatoly. If this is the case then we need to consider new procedures for cleaning/testing/replacing the caps on the boards before the lamination.   
 
- Beginning with the wire frame #5, we started testing the HV caps before stringing. It requires some conditioning but few days were enough to test wire frame #5. Now we are having problems with wire frame #6. We identified so far 8 caps that need to be replaced. After the meeting we continued with the tests and we found another 4, so 12 in total. Anatoly, who removed the caps, mentioned that on 5 of these there were solder balls below the caps somewhere between the pads (see pictures linked above). The balls are actually flat (like coins). Therefore we suspect that they were there before the caps were un-soldered by Anatoly. If this is the case then we need to consider new procedures for cleaning/testing/replacing the caps on the boards before the lamination.   
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== Engineering ==
 
== Engineering ==
  
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- Bill: We measured the flatness of the new (wire plane #2) package that had now the new strong-back mounted on one side. There is a significant improvement but we still see +/- 11/1000" variations and some of them coming from the hubs. Bill/Dave will do more measurements.
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- Bill showed pictures of the deadened area of one of the samples made by the W&M microscope. The surfaces, including the transition areas, look well polished and free of any sharp edges. The thicknesses along the wire and also for the different wires are very similar of about 66-68 microns, except at the very end of the deadened area where it is ~57 microns.  
  
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- We discussed whether we need to cut the new gusset rings. The first two were cut but it resulted in some flatness problems. The point is that the gusset ring is right against the end window mylar that has ~0.5 Ohms/square resistivity and the cut in case of magnet quenching, will not help. There were discussions with Fernando after the meeting and he will look again into this. Important point he made is that in case of high current the aluminum will evaporate preventing higher currents. But then the question is what will happen with the aluminized mylar.
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- Do we need to cut the gusset ring? As estimated by Eugene in case of magnet trip without the cut we may have up to ~7mV e.m.f. That means in the ring (~10^-3 Ohms) we will have 7A current and the power will by ~50 mWatt. Nobody from the participants of the meeting was aware of any problem this power can cause.
  
 
== Electronics ==
 
== Electronics ==

Revision as of 11:57, 19 August 2011

August 18, 2011 FDC meeting

Agenda

  1. Production Construction Tracking (Dave)
  2. Engineering (Bill)
  3. Electronics update (Chris)
  4. Chamber testing at EEL126 (Beni)
    • Status of cell#2
    • Deadened area tests
  5. Other


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