Difference between revisions of "Minutes-9-13-2012"

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(Created page with "September 13, 2012 FDC meeting = Agenda = # Production [http://www.jlab.org/Hall-D/detector/fdc/production/FDC_Construction_September_13_2012.xlsx Construction Tracking] (Dave) ...")
 
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# Engineering (Bill)
 
# Engineering (Bill)
 
# Electronics (Chris, Nick)
 
# Electronics (Chris, Nick)
−
# Third package tests [https://halldweb1.jlab.org/elog-halld/FDC FDC E-log] (Beni)
+
# Third package tests [https://halldweb.jlab.org/elog-halld/FDC FDC E-log] (Beni)
−
# [http://www.jlab.org/Hall-D/detector/fdc/general/tdr.pdf TDR, pages 132-145] (Lubomir)
+
# [http://www.jlab.org/Hall-D/detector/fdc/general/tdr.pdf TDR, pages 132-143] (Lubomir)
 
# Other
 
# Other
−
 
−
<!--
 
  
 
= Minutes =
 
= Minutes =
  
−
Participants: Eugene, Bill, Dave, Simon, Vlad, Beni, and Lubomir
+
Participants: Eugene, Bill, Dave, Simon, Chris, Vlad, Beni, and Lubomir
  
 
== Production ==
 
== Production ==
  
−
- Dave: Need to put the cards on another two cathodes and we will be ready with the first three cells that will go in package #1. Chris put the resistors on one PCB set and Casey started today making the PCB ring for wire frame #28. It will be laminated beginning of next week and Anatoly will put and test the HV caps before the end of the next week.  
+
- Dave: 7 cathodes ready, another 5 need daughter cards to be glued. Will have 200 new cards (Lubomir) beginning of next month, we better use them for the rest of the cathodes; so far we have 3 cathodes with refurbished daughter cards. One new wire frame (#29) is ready for stringing, Anatoly just put HV caps and tested it. Adam (Vision Machine) will bring one g10 wire frame next Wednesday and another three on Friday. After Rohacell lamination Adam will fly cut them and we will have the first frame for the PCB lamination next Friday. Bill: Adam will need our de-humidifier.  
  
−
- Eugene: in order to expedite the solenoid testing, the plan so far is that three of our techs will be taken from us for two months, October and November. Dave and Anatoly will still work on the FDC. In case we need somebody for a short time, like half a shift, we should discuss this with Tim and Tom in advance.
+
- Lubomir: we may try to fix the wire frames #27 and #28 that are drawing high current. Suspect the via of the HV trace that connects the bottom trace just against the Rohacell. If this is the problem, can be fixed by drilling a hole from the back side. Bill agreed and we will try it next month when we will have time.
−
 
+
−
- Just for the record: starting about Sunday evening or Monday morning (09/02-03) the humidity in the clean room was above 60%. On Tuesday it was 63% all day. A faulty fan was found that was replaced on Wednesday before lunch; in the afternoon the humidity returned back to normal for the season, 47-49%. In the clean room we have only the fourth package with four cell assembled being flushed with Nitrogen.
+
−
 
+
−
- Vlad updated the grounding scheme including the ~100 additional grounds, that is linked above.
+
  
 
== Cathode corrosion ==
 
== Cathode corrosion ==
  
−
- Another test with Viton+Apiezon was done in the vacuum chamber, this time using a spacer ring to have the right pressure on the O-ring applied with a lead brick. This time the lamps were kept on continuously over the holiday weekend; one of them burned on Monday. The copper changed color (picture attached). Unlike the previous test (with higher pressure) we could see only tiny holes through the copper using microscope and it's not not clear if they are a result of mechanical or chemical reaction.  
+
- On Monday we started a test with a cathode (the demo one) using two techniques to protect the copper from corrosion: one side lightly coated with Hysol, the other with Kapton films sitting on Apiezon. We installed this cathode in a cell with Viton+Apiezon and started flushing with gas at 200ccpm (to have enough flow through the oxygen sensor). Some leakage was found (< 10^-4) at the Kapton side but that pressure inside is very high due to the higher flow rate per cell. Interestingly leakages were found at the two transition regions between the Kapton and Hysol areas, probably the Hysol layer is thicker than the Kapton film. Importantly, the oxygen went down to 180ppm in three days.  
  
−
- Olga analyzed the sample from the previous test, Viton+Apiezon at high pressure, and this time there's no sulfur visible, except at one place outside of the O-ring and Apiezon area, most likely pollution.
+
- We will wait till Monday to see the final oxygen percentage and will open the test package. If everything is OK we want to use the Hysol technique for the first half of the first package. Bill wanted to know if Dave is happy with the Hysol coating, then they discussed how to improve the flatness of the Hysol layer. In any case we will practice more before working on the production cathodes. Bill also proposed to use conformal coating instead of Hysol, but Eugene and Lubomir didn't agree since it introduces new material and there are complains from drift chamber groups about possible out-gassing. Even we have some parts of the PCBs coated inside the gas volume and we try to find the same material, we still need to do long tests
 +
before we are sure it will not harm the chamber. As for the other technique, using Apiezon on big areas it's messy and not possible to clean, it may start leaking at higher temperature when chamber is in vertical position?
  
−
- We started several experiments coating the cathode foil below the O-ring:
+
- Vlad started a new test in the vacuum chamber now adding a sample with Viton+Apiezon against cathode foil that was coated with Hysol. The chamber will stay at very high temperature (close to 100deg C) and 100% humidity till Monday.
−
# Using Kapton film glued with Hysol: doesn't work due to many bubbles and wrinkles.
+
−
# Coating only with Hysol: we used a "bad" cathode from package 1 and on the next day the Hysol spread away from the O-ring place that had some residue from the EPDM. Also, the coated surface was not very even. Trying to fix these problems we applied one more coating. We will also try this on a cathode that has not been damaged.
+
−
# Using Kapton film sitting on Apiezon (Anatoly's proposal); not real gluing but should work. The problem is that it will be very messy and Apiezon may accidentally go on the wires.
+
−
 
+
−
- Vlad proposed to study the rate of the chemical reaction (R) as a function of the temperature: R2=R1*Q^(T2-T1)/10degC. Q is between ~2 to 4 and can be measured doing our tests with the vacuum chamber at two different temperatures. The main question is how to measure the rate: we will measure the resistance and see how it changes with the time. The experiments should be done in normal conditions (other than the temperature) so that we can extrapolate the results.
+
  
 
== Engineering ==
 
== Engineering ==
  
−
- The tools (strong-backs) to move the cathodes work great using new and increased number (from 6 to 11) of suction cups.
+
- Bill answering Eugene's questions: the three carts that will support FDC, CDC and the FDC cables will be ready in a couple of weeks. The fiducials will be glued to the gusset ring and then surveyed w.r.t. wire planes and the cart at Blue Crab. Another survey will be done when the cart is at the platform and another one of the optical targets at the front and back of the FDC when the detector is installed. Bill will estimate the man-weeks for the surveys.
  
−
== Third package tests ==
+
- When there's time in the next two months, Dave will start working on the cooling system of the third package in 126. Bill will make sure we have all the parts and tools.
 +
 +
== Electronics ==
  
−
- Beni made progress working with Cody in reading the fADC125 with the Linux ROC; time out is still there but can recover.
+
- Nick: by next Wednesday we will have another set of PCBs populated. We will start testing the LV system, Beni needs two LV cables for the two fADC125 he's planing to use in the DAQ.
  
−
- The noise in the second cell was reduced by installing additional ground there. It turned out it was supposed to be there, just we missed to install it. We still can't use one negative HV sector and have two missing wire signals, because of the cards or chamber itself.
+
== Third package tests ==
−
 
+
−
== Other ==
+
  
−
- Beni: gas system discussions in the control group: can save money installing less low-pressure sensors by multiplexing using manifolds.
+
- Beni and Cody did tests with another VME (not VXS) crate and found the same problems with the fADC. They also found that when you put the fADC with an extension card at the last slot that doesn't work (#12), i.e. increasing the length of the VME bus, it worked better; so it's a matter of signal propagation in the bus. Next they will try to lower the fADC frequency from 80 to 40MHz.
 +
 
 +
== TDR ==
  
−
-->
+
- We are almost ready with the draft version of the TDR. Some numbers remain to be checked, Bill will help also with the main parameters of the cooling system and with one picture of the FDC cell. We discussed if the cooling system for all the detectors should be covered in a separate section. As for the FDC and CDC gas system, certainly it's worth having a separate section. Latest TDR version is linked above.

Latest revision as of 00:43, 1 April 2015

September 13, 2012 FDC meeting

Agenda

  1. Production Construction Tracking (Dave)
  2. Cathode corrosion
    • Recent tests
  3. Engineering (Bill)
  4. Electronics (Chris, Nick)
  5. Third package tests FDC E-log (Beni)
  6. TDR, pages 132-143 (Lubomir)
  7. Other

Minutes

Participants: Eugene, Bill, Dave, Simon, Chris, Vlad, Beni, and Lubomir

Production

- Dave: 7 cathodes ready, another 5 need daughter cards to be glued. Will have 200 new cards (Lubomir) beginning of next month, we better use them for the rest of the cathodes; so far we have 3 cathodes with refurbished daughter cards. One new wire frame (#29) is ready for stringing, Anatoly just put HV caps and tested it. Adam (Vision Machine) will bring one g10 wire frame next Wednesday and another three on Friday. After Rohacell lamination Adam will fly cut them and we will have the first frame for the PCB lamination next Friday. Bill: Adam will need our de-humidifier.

- Lubomir: we may try to fix the wire frames #27 and #28 that are drawing high current. Suspect the via of the HV trace that connects the bottom trace just against the Rohacell. If this is the problem, can be fixed by drilling a hole from the back side. Bill agreed and we will try it next month when we will have time.

Cathode corrosion

- On Monday we started a test with a cathode (the demo one) using two techniques to protect the copper from corrosion: one side lightly coated with Hysol, the other with Kapton films sitting on Apiezon. We installed this cathode in a cell with Viton+Apiezon and started flushing with gas at 200ccpm (to have enough flow through the oxygen sensor). Some leakage was found (< 10^-4) at the Kapton side but that pressure inside is very high due to the higher flow rate per cell. Interestingly leakages were found at the two transition regions between the Kapton and Hysol areas, probably the Hysol layer is thicker than the Kapton film. Importantly, the oxygen went down to 180ppm in three days.

- We will wait till Monday to see the final oxygen percentage and will open the test package. If everything is OK we want to use the Hysol technique for the first half of the first package. Bill wanted to know if Dave is happy with the Hysol coating, then they discussed how to improve the flatness of the Hysol layer. In any case we will practice more before working on the production cathodes. Bill also proposed to use conformal coating instead of Hysol, but Eugene and Lubomir didn't agree since it introduces new material and there are complains from drift chamber groups about possible out-gassing. Even we have some parts of the PCBs coated inside the gas volume and we try to find the same material, we still need to do long tests before we are sure it will not harm the chamber. As for the other technique, using Apiezon on big areas it's messy and not possible to clean, it may start leaking at higher temperature when chamber is in vertical position?

- Vlad started a new test in the vacuum chamber now adding a sample with Viton+Apiezon against cathode foil that was coated with Hysol. The chamber will stay at very high temperature (close to 100deg C) and 100% humidity till Monday.

Engineering

- Bill answering Eugene's questions: the three carts that will support FDC, CDC and the FDC cables will be ready in a couple of weeks. The fiducials will be glued to the gusset ring and then surveyed w.r.t. wire planes and the cart at Blue Crab. Another survey will be done when the cart is at the platform and another one of the optical targets at the front and back of the FDC when the detector is installed. Bill will estimate the man-weeks for the surveys.

- When there's time in the next two months, Dave will start working on the cooling system of the third package in 126. Bill will make sure we have all the parts and tools.

Electronics

- Nick: by next Wednesday we will have another set of PCBs populated. We will start testing the LV system, Beni needs two LV cables for the two fADC125 he's planing to use in the DAQ.

Third package tests

- Beni and Cody did tests with another VME (not VXS) crate and found the same problems with the fADC. They also found that when you put the fADC with an extension card at the last slot that doesn't work (#12), i.e. increasing the length of the VME bus, it worked better; so it's a matter of signal propagation in the bus. Next they will try to lower the fADC frequency from 80 to 40MHz.

TDR

- We are almost ready with the draft version of the TDR. Some numbers remain to be checked, Bill will help also with the main parameters of the cooling system and with one picture of the FDC cell. We discussed if the cooling system for all the detectors should be covered in a separate section. As for the FDC and CDC gas system, certainly it's worth having a separate section. Latest TDR version is linked above.

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