Difference between revisions of "Minutes-5-31-2012"

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# Engineering update (Bill)
 
# Engineering update (Bill)
 
# Electronics update (Chris)
 
# Electronics update (Chris)
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# Test set-up in 126 [https://halldweb1.jlab.org/elog-halld/FDC FDC E-log] (Beni)
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# Test set-up in 126 [https://halldweb.jlab.org/elog-halld/FDC FDC E-log] (Beni)
 
# Other
 
# Other
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−
<!--
 
  
 
= Minutes =
 
= Minutes =
  
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Participants: Bill, Dave, Chris, Nick, Mark, Simon, Beni, and Lubomir.   
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Participants: Bill, Dave, Chris, Nick, Mark, Vlad, Beni, and Lubomir.   
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+
 
−
   
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== Production ==
 
== Production ==
  
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- Dave for package #4 production: on wire frame #27 tension measurements were done, #28 will go on the stringing table next. The last wire frame for the package will go on the table by the end of the next week. #26 and #27 will be deadened on Monday. #26 has components, Chris will put components on #27 Monday/Tuesday. Working now on all the remaining cathodes for the package. Expect to have all the cathode for the package ready in two weeks. Bill asked Dave to put the wire frame numbers on the samples for the wire deadening.
+
- Dave: wire plane #27 remains to be deadened, after tension measurements on #28 will be removed from the stringing table and will string the very last wire frame #8. Chris will put components on #28 next week. Cathode #53 (type-2) had a problem with gluing the ground plane: the Mylar pilled out from the frame. This is the first frame that was converted from type-1 to type-2 by filling the groove with epoxy, so most likely the surface that was epoxied and sanded was too smooth. Casey roughened it and a new foil was tensioned on it today; tomorrow we will know the result.  
  
−
- Third package was fully assembled a week ago and as of today the oxygen is 140ppm and it still may go a little down. For comparison we had 75ppm for one cell and 111ppm for four cells. Roughly we have ~10ppm contribution from each cell plus ~65ppm from the gas and gas system. In any case the oxygen is very low. All the cells were tested and all the channels are fine, except we had HV problem on the top cell: there was short (~1MOhm) to ground from two positive HV sectors. It turned out one shorts ONLY to the ground on the top cathode, and the other HV sector shorts ONLY to a particular strip on the top cathode. No connectivity was found to anything else, like wire frame ground, field wires etc. After the meeting we opened the package and as Dave predicted, we found two sense wires not completely cut, sticking up and making contact with the top cathode. The problem was fixed and we closed the package. Now we will have to wait one more week to get the oxygen down and do final tests.    
+
- Third package was removed from the assembly fixture and put aside on a table. For that all the metal pins had to be removed, then the package was turned upside down to insert the new pins and hubs. We connected the package to the gas to check the tightness: it was as good as it before this operation.  
  
−
== Engineering ==
+
- Today before the meeting we installed the first cell of the fourth package, and after the meeting we installed the second one. The plan is to put also the third cell tomorrow and close the package for flushing and testing. If everything goes smoothly we expect to be ready with the last three cells and install them in the week of June 11-15.   
  
−
- Bill: final tests on the design of the installation cart before bidding. Had further discussions with Tim and survey group on the fiducial scheme (Bill reminded us the scheme again).
+
- We started testing the first production wire frames that will be used as spares; all they had some kind of problem. We put the very first (that was submerged in water long time ago) between Lexan sheets and after one day flushing with gas, applied HV. We were able to reach 1500/-500V (to be compared with few hundred volts we could put before) but at this voltage the current started increasing with the time. We decided to stop with the tests, remove all the HV caps and test it again without caps. In case we still have problems then we have to consider making a new wire frame, but we don't have spare PCBs. Chris will look in the old PRs and also will ask the company for an estimate for 4 or 8 PCB sets (each 6 boards), as Bill suggested just to have more spares. For these PCBs we don't want them to put the HV caps.
  
−
- When installing the last two cells we had problems with the metal pins and had to put vacuum grease on them to make the insertion easy. To avoid bending of the pins, as Casey suggested, we want to put two handles and Bill will order them.
+
== Engineering update ==
  
−
== Electronics ==
+
- Bill: Caleb (the student who worked with him last summer) is back and will be working on the cooling system including its testing. Bill will modify one of the fixtures at Blue Crab to be used for the package spacers.
  
−
- Chris: Jim and Chuck made the drawings of the grounding clip. It will be Cu-Be 13mill thick and will have a force of 7.5lb; Bill: in this case we have to use Rohacell between the wire frame and the cathode. One company only responded to the bid: $2k for 500 clips (need ~120 per package). Chris submitted a PR.
+
== Electronics update ==
  
−
- After some discussions we figured out that we can easily extend the grounding to the cathode from the top cell. We just extend the Cu foil to that cathode and put the clips that we have now on the top of the copper foil, thus we will also prevent damaging the cathode foil. In this case we may not need to do the inter-cell ground connections.  
+
- Chris on grounding clips: delay with the PR, finally yesterday the clips were ordered, but the delivery time is 3-4 weeks. The third package will have to wait for that, we can't install anything on it before the grounding. Chris will ask them to expedite the order, at least for smaller quantities. According to Nick in ~4 weeks from now we will have all needed to supply one package with LV. Bill: when the cooling system will be needed? - most likely for the fall because we will not have the fADC125 modules before that.
  
−
- Before making the clips we have to test them but the company will not give us samples, for that they need to set up the production. Bill suggested to use the 7mill brass shimming plates (that we have) and try to make a clip according to the drawings that Chris will send. At least we can test it before the production starts.   
+
== Test set-up at 126 ==
  
−
== Tests with first package at 126 ==
+
- Beni: No news, done with the tests of the first package and waiting for the third one. In the mean time has to work on two-crate configuration with CODA-light. A student will be working (with the help of Hovanes) on the controls for the testing set-up.
−
 
+
−
- Beni: working on the wire resolution. So far it is much worse than it was in the prototype, about ~400 microns. Beni traced down the problem to the very bad timing resolution of ~14ns. It was estimated using a simplified scheme: separating only vertical (from the Indiana chambers) tracks and comparing the timings from the parallel wires in the first and fourth packages. Most likely to problem is due to the oxygen in the gas, but Beni wants to check the F1TDC using different mode. Also it could be a result of a poor angular resolution of the Indiana chambers, but to see its effect it must be worse than 5mrad. Beni will report on this in the Collaboration meeting.
+
  
 
== Other ==
 
== Other ==
  
−
- Vladimir is arriving on May 30 for six months, will be helping with the package tests.  
+
- Gas system: Beni asked Bill if possible to increase the diameter of the gas supply tubes; the impedance looks too high now. Outside of the detector the tube material will be stainless steel to minimize the outgassing. The exhaust line will go outside of the hall as well, to allow use of flammable gases.  Beni will discuss this with Narciso Gomez today.
−
 
+
−
- Due to the Collaboration meeting Monday-Wednesday next week, unless there's something urgent, we will not have FDC meeting next week.
+
−
 
+
−
-->
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Latest revision as of 18:02, 31 March 2015

May 31, 2012 FDC meeting

Agenda

  1. Production Construction Tracking (Dave)
    • Production status
    • Fourth package assembly
    • Spare wire planes
  2. Engineering update (Bill)
  3. Electronics update (Chris)
  4. Test set-up in 126 FDC E-log (Beni)
  5. Other

Minutes

Participants: Bill, Dave, Chris, Nick, Mark, Vlad, Beni, and Lubomir.

Production

- Dave: wire plane #27 remains to be deadened, after tension measurements on #28 will be removed from the stringing table and will string the very last wire frame #8. Chris will put components on #28 next week. Cathode #53 (type-2) had a problem with gluing the ground plane: the Mylar pilled out from the frame. This is the first frame that was converted from type-1 to type-2 by filling the groove with epoxy, so most likely the surface that was epoxied and sanded was too smooth. Casey roughened it and a new foil was tensioned on it today; tomorrow we will know the result.

- Third package was removed from the assembly fixture and put aside on a table. For that all the metal pins had to be removed, then the package was turned upside down to insert the new pins and hubs. We connected the package to the gas to check the tightness: it was as good as it before this operation.

- Today before the meeting we installed the first cell of the fourth package, and after the meeting we installed the second one. The plan is to put also the third cell tomorrow and close the package for flushing and testing. If everything goes smoothly we expect to be ready with the last three cells and install them in the week of June 11-15.

- We started testing the first production wire frames that will be used as spares; all they had some kind of problem. We put the very first (that was submerged in water long time ago) between Lexan sheets and after one day flushing with gas, applied HV. We were able to reach 1500/-500V (to be compared with few hundred volts we could put before) but at this voltage the current started increasing with the time. We decided to stop with the tests, remove all the HV caps and test it again without caps. In case we still have problems then we have to consider making a new wire frame, but we don't have spare PCBs. Chris will look in the old PRs and also will ask the company for an estimate for 4 or 8 PCB sets (each 6 boards), as Bill suggested just to have more spares. For these PCBs we don't want them to put the HV caps.

Engineering update

- Bill: Caleb (the student who worked with him last summer) is back and will be working on the cooling system including its testing. Bill will modify one of the fixtures at Blue Crab to be used for the package spacers.

Electronics update

- Chris on grounding clips: delay with the PR, finally yesterday the clips were ordered, but the delivery time is 3-4 weeks. The third package will have to wait for that, we can't install anything on it before the grounding. Chris will ask them to expedite the order, at least for smaller quantities. According to Nick in ~4 weeks from now we will have all needed to supply one package with LV. Bill: when the cooling system will be needed? - most likely for the fall because we will not have the fADC125 modules before that.

Test set-up at 126

- Beni: No news, done with the tests of the first package and waiting for the third one. In the mean time has to work on two-crate configuration with CODA-light. A student will be working (with the help of Hovanes) on the controls for the testing set-up.

Other

- Gas system: Beni asked Bill if possible to increase the diameter of the gas supply tubes; the impedance looks too high now. Outside of the detector the tube material will be stainless steel to minimize the outgassing. The exhaust line will go outside of the hall as well, to allow use of flammable gases. Beni will discuss this with Narciso Gomez today.

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