Difference between revisions of "Minutes-6-14-2012"

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(Created page with "June 14, 2012 FDC meeting = Agenda = # Production [http://www.jlab.org/Hall-D/detector/fdc/production/FDC_Construction_Jun_14_2012.xlsx Construction Tracking] (Dave) #* Producti...")
 
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# Engineering update (Bill)
 
# Engineering update (Bill)
 
# Electronics update (Chris)
 
# Electronics update (Chris)
# Cable assignment and labeling (Vlad)
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# [http://www.jlab.org/Hall-D/detector/fdc/documents/preamp_position_in_racks.pdf Cable assignment and labeling] (Vlad)
 +
# Gas system (Beni)
 
# Test set-up in 126 (Beni)
 
# Test set-up in 126 (Beni)
# Other [https://halldweb1.jlab.org/elog-halld/FDC FDC E-log]
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# Other [https://halldweb.jlab.org/elog-halld/FDC FDC E-log]
 
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<!--
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= Minutes =
 
= Minutes =
  
Participants: Bill, Dave, Chris, Nick, Vlad, Beni, and Lubomir.   
+
Participants: Caleb, Dave, Chris, Nick, Vlad, Simon, Beni, and Lubomir.   
 
    
 
    
 
== Production ==
 
== Production ==
  
- Dave: working on the last wire frame, Casey finished wire gluing. Chris will put elements on a wire frame tomorrow. Also two wire planes will be deadened tomorrow/Monday.  
+
- Dave: on last wire frame (#18) had to replace one sense wire and twice one field wire due to incorrect tension, now it's out of the stringing table and Chris will put the components tomorrow. Two wire frames will be deadened tomorrow, and #18 will be deadened on Monday. Cathode #55, the last for package #4, is ready too. On Tuesday/Wednesday we will continue with the stacking of the fourth package. Working on spare cathodes #54, 57, and 59.
Cathode #47 (type-2) had a problem on strip #1: there is a small bump of epoxy on the trace leading to the connector; it was put there before to fix small deformation of the Kapton foil. Since the bump was very close to the O-ring and solid g10 surfaces we were afraid that it may create gas leakage. After trying to remove part of the epoxy we damaged the copper trace. At this point we decided to put another cathode in the fourth package. Later the trace was fixed by applying conductive epoxy (3-4 Ohms strip to connector resistance) but we decided to use this cathode as a spare and make another cathode for the fourth package (#55) which will be ready by Wednesday-Thursday. Also by that time we will have all the wire frames ready to finish the fourth package.
+
  
- Dave predicts we will have all the elements, also the spares, done by the end of June. Then the work will be focused on the first and second package refurbishment. Related to that Bill asked when we can do full package tests in 126. Answer: everything depends on the fADC125 availability. We need to discuss this with Fernando since it will delay the FDC production/testing, and make a plan at least for partial testing of the cathodes using as many fADC125 as possible.
+
- The problem with the noise on cell #4 was solved: a tiny piece of epoxy (or something like that) got stuck to the sense wire in that area. Casey cleaned it but that was not easy. The package was closed on Friday and this week was tested: the noise disappeared.  
  
- Three cells were installed on the fourth package at the end of the last week. Vlad reported on the tests: oxygen went down to 77ppm, all channels were tested with scope/source and are working fine. However, on the top cell (#4) he found a point source of noise (~50kHz, high amplitude) visible on one wire (#21), top strip and bottom strip; most likely standard hair-on-wire problem. On cell #5 Vlad found that the current increased in one day from ~20nA to ~200nA and then it was stable. We will keep the HV on #5 and depending how stable it is we will decide if we want to open it as well, or open ONLY the top cell (#4) to fox the high frequency noise.  
+
- Wire frame #1 can't be used at > 1900/-500V and at this voltage the current is very high (~1uA). Before the meeting Eugene agreed to purchase another 4 spare sets of PCBs. A.s.a.p. before purchasing we want to test wire plane #2. It has a conductive spot from the chemical used for deadening, shortening a field and sense wire. We will test also the other two spare wire planes, but they seam to be fine. Then we will know how many new wire planes we need to build. We have only one extra G10 wire frame and in case we need more we have to order them, as well.
  
 
== Engineering update ==  
 
== Engineering update ==  
  
- Bill: busy with the tagger, but works with Caleb on the cooling system. Related to a question about the inter-package support tubes, Bill explained that the cables will not be tightened to that tube. This is because the diameter is smaller, the cables would be further away from BCAL and reduce the photon efficiency. To keep the cables straight between the packages Bill propose to use plastic rods/tubes inserted in the cable bundles.
+
- Caleb: Bill is busy, but he explained well details of the outer (outside of the FDC) part of the cooling system that will have Fluorinert and water loops. Caleb will work with Bill also on the testing of the cooling system.  
  
 
== Electronics update ==
 
== Electronics update ==
  
- Chris: grounding clips will come end of next week. Then we start with the ground installation on the third package at Blue Crab; Beni will help us. We discussed what additional material we will use: 1mil copper foil for grounding strips, Rohacell wrapped with something (Al foil?), and clips that we already have.
+
- Chris: LV cables have come. We discussed that it is worth setting up the LV system in 126 and later connecting the LV cables to the third package (when it will be in 126) but not applying voltage on most of them since we will need cooling.  
  
- Chris got a quote from San Francisco Circuits about purchase of additional PCBs, in case we can't fix some of the first four wire frames: $26.9K for 4 sets, and $37K for 8 sets (each set has 6 PCBs). These are quotes only the board production; Chris can do the stuffing of the boardsWe will replace the caps on the first wire frame and then decide if we need extra PCBs.  
+
== Cable assignment and labeling ==
 +
 
 +
- See the document above prepared by Vlad. It contains (in Excel format) a table of all the signal cables showing the label and the destination rack, crate, module, and connector. There's a scheme at the end of the document: half of the cables will go to the left and half to the right racks depending where the corresponding card is. Wire cables will be connected to F1TDCs, 6 modules per package per side occupying two crates with 12 modules each. 5 crates on each side will be filled with 15/14 fADC125s, having 18 modules per package per side. We decided to keep the channel information in the label (like FDC1,C5,D85B-108B).   
 +
 
 +
- The ordering of the connectors is generally (from left to right in the crates) starting from the lower package, cell number, channel number. Beni suggested that we may want to split the cards with highest rates into different fADC modules. It's easy to implement, but we want to discuss this with Fernando, Cody, Gerard.
  
 
== Gas system ==
 
== Gas system ==
  
- Beni is in contact with Narciso Gomez about the gas system. We discussed if we would need to filter the water that according to the gas company would be less than 200ppm in the CO2 bottles. Lubomir: don't have to filter since 200ppm is low enough especially when the oxygen level is low. Beni was advised to contact the GTS gas company since JLab has a contract with it.   
+
- Beni is in contact with Narciso; soon we will have separate meeting about the gas system.   
  
 
== Test set-up at 126 ==
 
== Test set-up at 126 ==
  
- Vlad will start testing all the cathode channels of the first package with a source and scope. We want to see if there was some deterioration of the cathode connections done with the z-axis conductive tape. There are some indications for increased resistance (up to 5-6 Ohms) on a small percentage of cathode channels, about 3-4 channels per cathode, at Blue Crab. This, however, could be due to handling of the cathodes and once they are installed in a package there's no deterioration.  
+
- Beni: CODA-Light doesn't work with Linux ROCs so far. Will talk to Bryan Moffit if something can be done, if not possible we will have to move to the "heavy" CODA.
  
 +
- Vlad tested the cathodes of the top three cells of the first package in 126 with a source. The main complain is that on some of the channels there are no signals, but after unscrewing the card from the cooling tube it starts working. It is not clear why: probably the tube pulls/bends the card or the cathode frame. There were suggestions to tighten the tubes to the package evenly around the periphery with cables ties using the holes on the cathodes. Will be discussed with Bill.
 +
   
 
== Other ==
 
== Other ==
  
- Lubomir showed a GEANT model of the Helium Drift Chamber (at the FDC E-log). The model will be used first to study the BCAL photon efficiency. Important is that the diameter of the solid frame was increased and is now closer to the BCAL. This is possible because one can put the readout cards parallel to the z-axiz; this was not possible for the FDC due to the high density of the channels.
+
- Lubomir looked at some old runs with the second production chamber where we have used also 55Fe source and triggered with one strip. We don't have long tails in the signals (including with comics) as seen in the CDC with fADC125.
 
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-->
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Latest revision as of 06:22, 1 April 2015

June 14, 2012 FDC meeting

Agenda

  1. Production Construction Tracking (Dave)
    • Production status
    • Spare wire frames (Lubomir)
  2. Engineering update (Bill)
  3. Electronics update (Chris)
  4. Cable assignment and labeling (Vlad)
  5. Gas system (Beni)
  6. Test set-up in 126 (Beni)
  7. Other FDC E-log

Minutes

Participants: Caleb, Dave, Chris, Nick, Vlad, Simon, Beni, and Lubomir.

Production

- Dave: on last wire frame (#18) had to replace one sense wire and twice one field wire due to incorrect tension, now it's out of the stringing table and Chris will put the components tomorrow. Two wire frames will be deadened tomorrow, and #18 will be deadened on Monday. Cathode #55, the last for package #4, is ready too. On Tuesday/Wednesday we will continue with the stacking of the fourth package. Working on spare cathodes #54, 57, and 59.

- The problem with the noise on cell #4 was solved: a tiny piece of epoxy (or something like that) got stuck to the sense wire in that area. Casey cleaned it but that was not easy. The package was closed on Friday and this week was tested: the noise disappeared.

- Wire frame #1 can't be used at > 1900/-500V and at this voltage the current is very high (~1uA). Before the meeting Eugene agreed to purchase another 4 spare sets of PCBs. A.s.a.p. before purchasing we want to test wire plane #2. It has a conductive spot from the chemical used for deadening, shortening a field and sense wire. We will test also the other two spare wire planes, but they seam to be fine. Then we will know how many new wire planes we need to build. We have only one extra G10 wire frame and in case we need more we have to order them, as well.

Engineering update

- Caleb: Bill is busy, but he explained well details of the outer (outside of the FDC) part of the cooling system that will have Fluorinert and water loops. Caleb will work with Bill also on the testing of the cooling system.

Electronics update

- Chris: LV cables have come. We discussed that it is worth setting up the LV system in 126 and later connecting the LV cables to the third package (when it will be in 126) but not applying voltage on most of them since we will need cooling.

Cable assignment and labeling

- See the document above prepared by Vlad. It contains (in Excel format) a table of all the signal cables showing the label and the destination rack, crate, module, and connector. There's a scheme at the end of the document: half of the cables will go to the left and half to the right racks depending where the corresponding card is. Wire cables will be connected to F1TDCs, 6 modules per package per side occupying two crates with 12 modules each. 5 crates on each side will be filled with 15/14 fADC125s, having 18 modules per package per side. We decided to keep the channel information in the label (like FDC1,C5,D85B-108B).

- The ordering of the connectors is generally (from left to right in the crates) starting from the lower package, cell number, channel number. Beni suggested that we may want to split the cards with highest rates into different fADC modules. It's easy to implement, but we want to discuss this with Fernando, Cody, Gerard.

Gas system

- Beni is in contact with Narciso; soon we will have separate meeting about the gas system.

Test set-up at 126

- Beni: CODA-Light doesn't work with Linux ROCs so far. Will talk to Bryan Moffit if something can be done, if not possible we will have to move to the "heavy" CODA.

- Vlad tested the cathodes of the top three cells of the first package in 126 with a source. The main complain is that on some of the channels there are no signals, but after unscrewing the card from the cooling tube it starts working. It is not clear why: probably the tube pulls/bends the card or the cathode frame. There were suggestions to tighten the tubes to the package evenly around the periphery with cables ties using the holes on the cathodes. Will be discussed with Bill.

Other

- Lubomir looked at some old runs with the second production chamber where we have used also 55Fe source and triggered with one strip. We don't have long tails in the signals (including with comics) as seen in the CDC with fADC125.