Difference between revisions of "Minutes-3-18-2010"

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== Minutes ==
 
== Minutes ==
  
Participants: Lubomir, Eugene, Casey, Bill, Daniel, Roger, Brian, Mark, Beni, Fernando, Simon
+
Participants: Lubomir, Eugene, Casey, Bill, Daniel, Roger, Brian, Mark, Beni, Fernando, Simon, Tim
  
 
= FDC production =
 
= FDC production =
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- Fernando is working on the procurement of the HV and signal cables/connectors. He wants to make sure the lengths of the cables corresponds to the up-to-date plans.  
 
- Fernando is working on the procurement of the HV and signal cables/connectors. He wants to make sure the lengths of the cables corresponds to the up-to-date plans.  
  
- procurement of the cathodes: Eugene suggested to investigate the failure rate in soldering the flexes. Another showstopper is the decision about the size of the hole of the cathode strips. This issue was discussed during the last tracking meeting and Alex will investigate the effect of the copper material on the detector rates. We will aim to have the same hole size on all the FDC packages. Fortunately, the size of the wire deadening area that defines the sensitive area of the chamber, can be defined on a later stage.
+
- procurement of the cathodes: Roger and Dan are finalizing the cathode modifications. Eugene suggested to investigate the failure rate in soldering the flexes. Another showstopper is the decision about the size of the hole of the cathode strips. This issue was discussed during the last tracking meeting and Alex will investigate the effect of the copper material on the detector rates. We aim to have the same hole size on all the FDC packages. Fortunately, the decision about the the size of the wire deadening area that defines the sensitive area of the chamber, can be done later.
  
 
= Full scale prototype tests =
 
= Full scale prototype tests =
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- Beni summarized the results of the plateau and drift time investigations with different gas mixtures. So far there's nothing unexpected. Nevertheless, there are concerns about the uniformity of the detector response and the quality of the gas inside the chambers. Systematic analysis of the full scale prototype tests will be prepared for the next meeting. Lubomir showed results from the tests with 55Fe: the energy resolution is about 7%.   
 
- Beni summarized the results of the plateau and drift time investigations with different gas mixtures. So far there's nothing unexpected. Nevertheless, there are concerns about the uniformity of the detector response and the quality of the gas inside the chambers. Systematic analysis of the full scale prototype tests will be prepared for the next meeting. Lubomir showed results from the tests with 55Fe: the energy resolution is about 7%.   
  
- At the end of the testing, Beni made a series of HV studies with CO2 only. Before and after open the chamber he repeated the same tests.   
+
- At the end of the testing, Beni made a series of HV studies with CO2 only. Before and after opening the chamber he repeated the same tests. For all of the sectors, except maybe few, he was able to reach much higher HV than with Ar - CO2 mixtures.
 +
 
 +
- We observed corona discharge (bluish light hardly visble in the darkened  tend) at several places in one HV sector (at about +2700V/-400V) of the opened top chamber. The light was visible on the soldering pad of the last (for the sector) sense wire, later along the whole wire, and then on all the wires in that sector. Also we saw different spots blinking for few seconds coming from the dust on the wires. The corona discharge requires some condactivity between places with different potentil (through the air, or on the board) but is visible at places like edges or thin wires with very high electric field.   
 +
 
 +
- All this suggests that so far there are no indications that the HV problems are related to the boards, except maybe at few places due to impurities. The dust on the wires could explain most of the HV problems we had during the test.
 +
   
 
#* frame modification work: cathode sandwich and wire frame
 
#* frame modification work: cathode sandwich and wire frame
 
#* plans for layer 3  
 
#* plans for layer 3  

Revision as of 00:43, 19 March 2010

March 18, 2010 FDC meeting

Date: March 18, 2010

Tentative Agenda

  1. FDC production
    • production space update
    • FDC procurement plans
      • procurement of cables, connectors (HV, signal, LV)
      • procurement of cathodes: 1)flex connection, 2)beam hole size tracking meeting
  2. Full scale prototype tests
    • prototype test updates FDC Log Book
    • HV tests
    • frame modification work: cathode sandwich and wire frame
    • plans for layer 3
  3. Wire frame update
  4. Cathode frame redesign
    • cathode redesign status
    • rigid-flex assembly
  5. Wire winding
    • IUCF phase 3 contract
    • plans for wire winding upgrades
    • tension specs
  6. Other

Minutes

Participants: Lubomir, Eugene, Casey, Bill, Daniel, Roger, Brian, Mark, Beni, Fernando, Simon, Tim

FDC production

- Tim organized a visit to off-site properties (across the street) that could be used for FDC production/storage purposes. We are considering this as a possible option that needs to be further investigated. There was a second meeting after this one, discussing the requirements to use the space for the FDC production.

- Fernando is working on the procurement of the HV and signal cables/connectors. He wants to make sure the lengths of the cables corresponds to the up-to-date plans.

- procurement of the cathodes: Roger and Dan are finalizing the cathode modifications. Eugene suggested to investigate the failure rate in soldering the flexes. Another showstopper is the decision about the size of the hole of the cathode strips. This issue was discussed during the last tracking meeting and Alex will investigate the effect of the copper material on the detector rates. We aim to have the same hole size on all the FDC packages. Fortunately, the decision about the the size of the wire deadening area that defines the sensitive area of the chamber, can be done later.

Full scale prototype tests

- Beni finished the tests with Sr source, the prototype was moved back in the tend and the top layer was opened.

- Beni summarized the results of the plateau and drift time investigations with different gas mixtures. So far there's nothing unexpected. Nevertheless, there are concerns about the uniformity of the detector response and the quality of the gas inside the chambers. Systematic analysis of the full scale prototype tests will be prepared for the next meeting. Lubomir showed results from the tests with 55Fe: the energy resolution is about 7%.

- At the end of the testing, Beni made a series of HV studies with CO2 only. Before and after opening the chamber he repeated the same tests. For all of the sectors, except maybe few, he was able to reach much higher HV than with Ar - CO2 mixtures.

- We observed corona discharge (bluish light hardly visble in the darkened tend) at several places in one HV sector (at about +2700V/-400V) of the opened top chamber. The light was visible on the soldering pad of the last (for the sector) sense wire, later along the whole wire, and then on all the wires in that sector. Also we saw different spots blinking for few seconds coming from the dust on the wires. The corona discharge requires some condactivity between places with different potentil (through the air, or on the board) but is visible at places like edges or thin wires with very high electric field.

- All this suggests that so far there are no indications that the HV problems are related to the boards, except maybe at few places due to impurities. The dust on the wires could explain most of the HV problems we had during the test.

    • frame modification work: cathode sandwich and wire frame
    • plans for layer 3
  1. Wire frame update
  2. Cathode frame redesign
    • cathode redesign status
    • rigid-flex assembly
  3. Wire winding
    • IUCF phase 3 contract
    • plans for wire winding upgrades
    • tension specs
  4. Other