Difference between revisions of "Minutes-5-30-2013"

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# Full electronics test (Beni)
 
# Full electronics test (Beni)
 
# Other
 
# Other
 
<!--
 
  
 
= Minutes =
 
= Minutes =
  
Participants: Bill, Eugene, Glenn, Chris, Nick, Simon, Beni, and Lubomir.
+
Participants: Bill, Dave, Chris, Nick, Simon, Beni, Eugene, and Lubomir.
  
 
== Production ==
 
== Production ==
  
- Spare package: On Friday all the channels of cell #2 were tested and worked fine. Over the weekend the cell tripped from time to time. After we identified one HV sector (28 wires on the side of big wire numbers) that trips, we opened the package for a third time. In addition we noticed that the dark current goes down when removing one of the pre-amps in the same area at the signal side of the wires. There we found one suspicious soldering that was fixed. At the other side of the wires we found a small epoxy ball that was removed. After some additional cleaning of the wires in this area we closed the package again. It is being flushed with gas since Tuesday and will be checked on Friday.
+
- Spare package second cell: It was tested over the weekend. There were once-per-night trips on Friday and Saturday, but from Sunday till Wednesday there were no trips even keeping for several hours higher HV (+2250/-500V). Interestingly, it turned out that sometimes when using the low-intensity Fe source (100-200 kHz rates on chamber) the dark current may increase significantly. We suspect this is again a glow discharge triggered by the source. However, with the time this effect was diminishing. Most of the sense wires of this old wire board (#3) have some spots that are not shiny at one side of the chamber covering an area of about 1/3 of the total, which may be causing the glow discharge. In any case this effect disappears if using say 2120/-400V instead of the nominal 2100/-500V, that has the same gas gain. Therefore, we conclude it is not worth replacing all the wires and this wire plane can be used.
  
== Update on the corrosion test at MePhi ==
+
- Spare package third and fourth cells: were installed on Wedneday with the help of Tina (plus Casey, Anatoly and Lubomir). Later it turned out there's a significant leak in the second cell at two places at the spacer ring. When adding the third and fourth cells we first need to take out the top cathode type-3 of the second cell and most likely the O-ring jumped out of the groove. The O-rings on this spacer were very old, used also for tests of wire frames #3 and #6 between Lexan sheets. The plan is first to test the two new cells and then to open the package and fix the O-ring. If there's nothing to be fixed on the new cells we will access the O-ring by lifting the top two-and-a-half cells together. Hopefully we can get our HV supply back on Friday to test the cells over the weekend. The plan is to open the package on Thursday after the collaboration meeting.
 
+
- Vlad finished the test with 6 EPDM samples at 100degC at 100% humidity. The results are similar to what he got before with two samples: all the samples died between 6 and 24 hours. Now with higher statistics he estimates the activation energy to be 0.35+/-0.07 eV (consistent with the literature). Assuming the same chemical reaction for the Viton corrosion (just that Viton contains less amount of Sulfur) we estimate 1055 +/- 211 days live time at room temperature, but at 100% humidity. We don't know how to extrapolate the humidity down to 50%. It would be good to place O-ring samples outside of the packages to be tested whenever the FDC is taken out from the magnet for some maintenance.
+
  
 
== Engineering ==
 
== Engineering ==
  
- Bill, Casey and Beni performed the test of one loop of the cooling system. 22 pre-amps were attached to the cooling tube and powered with LV. The flow (at the right pressure) appeared to be in a good agreement with the ANSI model, however the temperature drop between the end and the beginning of the loop was 1.2deg instead 2deg as expected from the model. We discussed possible reasons for that: the exact power on the cards (we measure the current only, but the voltage on the card was not measured), the hot elements on the card, the regulator and the ASICs, are not in equilibrium for the short time of the experiment (about 10-15 min), bad thermal contact at the pre-amp clamp, or at the place where the thermo-couple is attached. The most important however is what is the temperature at the voltage regulator and ASICs when the cooling is on. After the meeting Beni and Bill repeated the test and the max temperature on one of the card at the voltage regulator was measured to be 42degC. Note that this card was connected with an individual LV cable.
+
- Beni and Bill measured the max temperature on one of the card at the voltage regulator: no more than 43degC with the cooling system running. Beni: when turning the cooling system on, the temperature on the voltage regulator changes very fast indicating good thermal contact to the cooling tube.
Also the ends of the thermo-couples were clamped together to check their calibration: no more 0.2deg difference was found. In any case, the test demonstrates that we can cool the pre-amps enough to keep the temperature of the hot elements well below the their limit.   
+
+
- The current cooling set-up (SMC chiller + 2kW water chiller) can ran for no longer than 15 min. If you cool down the water in advance (say to 3degC) it can ran probably for not more than an hour. Thus the only way to do the test with the full electronics will be to use the water chiller directly to cool the pre-amps.
+
  
- After the meeting Bill got response from the SMC experts: the chiller produces 2kW from the pump + 2kW from the compressor + max 2kW cooling power. So it requires 6kW water cooling. The water chiller we used in 126 is 2kW that's why it didn't work, but we will have no problems at the Hall.
+
- Bill once more on the SMC power: the chiller produces 2kW from the pump + 2kW from the compressor + max 2kW removed heat. Eugene: using 4kW to remove 2kW is something standard for such cooling systems.  
  
== Electronics ==
+
- Beni started working on Linux interface to the SMC chiller using USB to RS485 adapter. His plan is to test the communication and make some basic control functions, that need to be discussed further.
 
+
- Nick and Beni once more identified the problem with the CAEN HV module; it is there even without a load. Nick will contact CAEN.
+
  
 
== Full electronics tests ==
 
== Full electronics tests ==
  
- Beni for the firmware/software for fADC125: working progress. If it's not ready by the end of next week we will read out only the old modules.  
+
- Beni can now read the new fADC125 modules; demonstrated it by reading three such modules. The basic firmware/software made by Cody and Bryan allows to read the raw data from the modules. The extraction of the amplitudes and timings is done in the ROCs. Even this will slow down the DAQ, it will be enough for the full package test with comics. Beni, however, has some issues with the TI synchronization with the modules. Bryan was helping him after the meeting.  
  
- The truck was not available this week, so we will move the package next week. As discussed above, we will use water for cooling.
+
- Right after the meeting we moved the third package from Blue Crab to EEL126. The package was connected to the gas and the pressure is OK. On Tuesday Casey will connect the package to the water chiller. The cabling will be done after the collaboration meeting.
  
 
== Other ==
 
== Other ==
  
 
- No meeting next week due to the collaboration meeting.
 
- No meeting next week due to the collaboration meeting.
 
-->
 

Latest revision as of 17:26, 30 May 2013

May 30, 2013 FDC meeting

Agenda

  1. Production Construction Tracking
    • Spare package status
  2. Engineering (Bill)
    • Cooling system test
  3. Full electronics test (Beni)
  4. Other

Minutes

Participants: Bill, Dave, Chris, Nick, Simon, Beni, Eugene, and Lubomir.

Production

- Spare package second cell: It was tested over the weekend. There were once-per-night trips on Friday and Saturday, but from Sunday till Wednesday there were no trips even keeping for several hours higher HV (+2250/-500V). Interestingly, it turned out that sometimes when using the low-intensity Fe source (100-200 kHz rates on chamber) the dark current may increase significantly. We suspect this is again a glow discharge triggered by the source. However, with the time this effect was diminishing. Most of the sense wires of this old wire board (#3) have some spots that are not shiny at one side of the chamber covering an area of about 1/3 of the total, which may be causing the glow discharge. In any case this effect disappears if using say 2120/-400V instead of the nominal 2100/-500V, that has the same gas gain. Therefore, we conclude it is not worth replacing all the wires and this wire plane can be used.

- Spare package third and fourth cells: were installed on Wedneday with the help of Tina (plus Casey, Anatoly and Lubomir). Later it turned out there's a significant leak in the second cell at two places at the spacer ring. When adding the third and fourth cells we first need to take out the top cathode type-3 of the second cell and most likely the O-ring jumped out of the groove. The O-rings on this spacer were very old, used also for tests of wire frames #3 and #6 between Lexan sheets. The plan is first to test the two new cells and then to open the package and fix the O-ring. If there's nothing to be fixed on the new cells we will access the O-ring by lifting the top two-and-a-half cells together. Hopefully we can get our HV supply back on Friday to test the cells over the weekend. The plan is to open the package on Thursday after the collaboration meeting.

Engineering

- Beni and Bill measured the max temperature on one of the card at the voltage regulator: no more than 43degC with the cooling system running. Beni: when turning the cooling system on, the temperature on the voltage regulator changes very fast indicating good thermal contact to the cooling tube.

- Bill once more on the SMC power: the chiller produces 2kW from the pump + 2kW from the compressor + max 2kW removed heat. Eugene: using 4kW to remove 2kW is something standard for such cooling systems.

- Beni started working on Linux interface to the SMC chiller using USB to RS485 adapter. His plan is to test the communication and make some basic control functions, that need to be discussed further.

Full electronics tests

- Beni can now read the new fADC125 modules; demonstrated it by reading three such modules. The basic firmware/software made by Cody and Bryan allows to read the raw data from the modules. The extraction of the amplitudes and timings is done in the ROCs. Even this will slow down the DAQ, it will be enough for the full package test with comics. Beni, however, has some issues with the TI synchronization with the modules. Bryan was helping him after the meeting.

- Right after the meeting we moved the third package from Blue Crab to EEL126. The package was connected to the gas and the pressure is OK. On Tuesday Casey will connect the package to the water chiller. The cabling will be done after the collaboration meeting.

Other

- No meeting next week due to the collaboration meeting.