Difference between revisions of "Minutes-2-23-2012"

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# Other
 
# Other
  
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= Minutes =
 
= Minutes =
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== Production ==
 
== Production ==
  
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- Dave:  Deadened the first wire plane of package 3 with the larger diameter using the procedure with increased current and the same time as for the smaller diameter, but adding extra polishing cycle. Working on four cathodes now and on the last wire frame for the third package. One more cathode to finish the package. We estimated that for the  
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- Dave:  Deadened the first wire plane of package 3 with the larger diameter using the procedure with increased current and the same time as for the smaller diameter, but adding extra polishing cycle. Working on four cathodes now and on the last wire frame for the third package. One more cathode to finish the package. There's not much space now to start the fourth package. Testing the chambers of the third package will be the bottleneck since it takes time to flush the chambers with gas. We will try to use weekends for that if possible. Third package was started partially end of November, so less than three months ago. Still we need to work on the subsystems for both package 2 and 3.
  
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- Two more electroplating samples were made. One with the original procedure with extra polishing; before using the same procedure all the wires were fine except one. Second sample with increasing the time instead of the current compared to the 6cm-diameter original procedure, and in addition the polishing current was increased to have a ratio of 3 w.r.t electroplating current. Will be waiting for the microscope pictures from Olga to make a decision.  
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- First cell of the third package was assembled yesterday, flushed with gas over night on today we were able to apply HV which by now is already the nominal one. The dark currents are very low. If it holds over the night we will assume that the wire deadening procedure works and we will continue tomorrow with the deadening of the next wire plane. Tomorrow also we will test the first cell and if everything is OK will try to assemble the second cell so that we can use the weekend to flush it.  
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== First package testing ==
 
== First package testing ==
  
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- Beni showed results posted in the new FDC Elog linked above, entries #9-13. The wires of the top four planes are connected to the electronics. All channels are working fine now, except one noisy. To reduce the noise we had to increase the threshold to 20V on the supply (Vth=2.0V, or ~40mV effective threshold after the amplifier) which is close to the maximum possible value for the pre-amp of 25V! Beni made a code to estimate the chamber efficiencies using IU chamber tracks projecting them on the FDC cells and looking for at least one wire firing on the corresponding cell. One can see (entry #11) one side of all the cells having higher efficiencies, most likely correlated with the gas input. Using signals from particular wires Beni estimated the FDC wire orientation w.r.t. external tracking system and in between the cells (#13).
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- Beni showed results posted in the new FDC Elog linked above, entries #9-13.  
  
 
- Lubomir: good start for the first package, all wires working, no HV trips below 2150V with 50/50 Ar/CO2, while two channels tripped at 2200V which corresponds to a high gain of >10^5. Changing the HV from 2100/-500V to 2200/-500V (entry #12) improved the efficiency significantly. Now testing 21500/-500V. On the other hand we should try different ways to reduce the noise. One is to improve the LV distribution that contributes now to the noise problem due to voltage drops over the cables. After the meeting Beni installed  new LV cables from Chris, one per plane, and the noise was reduced so that we have now 15V threshold.     
 
- Lubomir: good start for the first package, all wires working, no HV trips below 2150V with 50/50 Ar/CO2, while two channels tripped at 2200V which corresponds to a high gain of >10^5. Changing the HV from 2100/-500V to 2200/-500V (entry #12) improved the efficiency significantly. Now testing 21500/-500V. On the other hand we should try different ways to reduce the noise. One is to improve the LV distribution that contributes now to the noise problem due to voltage drops over the cables. After the meeting Beni installed  new LV cables from Chris, one per plane, and the noise was reduced so that we have now 15V threshold.     

Revision as of 19:37, 23 February 2012

February 23, 2012 FDC meeting

Agenda

  1. Production Construction Tracking (Dave)
    • Production status
    • Testing at Blue Crab (Lubomir)
  2. First package tests FDC ELOG (Beni, Lubomir)
  3. Engineering update[1],cooling manifold (Bill)
  4. Electronics update (Nick)
  5. Other


Minutes

Participants: Bill, Dave, Nick, Elton, Mark, Simon, Beni, and Lubomir.

Production

- Dave: Deadened the first wire plane of package 3 with the larger diameter using the procedure with increased current and the same time as for the smaller diameter, but adding extra polishing cycle. Working on four cathodes now and on the last wire frame for the third package. One more cathode to finish the package. There's not much space now to start the fourth package. Testing the chambers of the third package will be the bottleneck since it takes time to flush the chambers with gas. We will try to use weekends for that if possible. Third package was started partially end of November, so less than three months ago. Still we need to work on the subsystems for both package 2 and 3.

- First cell of the third package was assembled yesterday, flushed with gas over night on today we were able to apply HV which by now is already the nominal one. The dark currents are very low. If it holds over the night we will assume that the wire deadening procedure works and we will continue tomorrow with the deadening of the next wire plane. Tomorrow also we will test the first cell and if everything is OK will try to assemble the second cell so that we can use the weekend to flush it.


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