Difference between revisions of "Minutes-8-29-2013"

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# Other
 
# Other
  
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= Minutes =
 
= Minutes =
  
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Participants: Bill, Chris, Nick, Simon, Vlad, Beni, Glenn, and Lubomir.
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Participants: Bill, Eugene, Chris, Simon, Vlad, and Lubomir.
  
 
== Installation preparations ==
 
== Installation preparations ==
  
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- We are done with the production and will continue discussing the installation. We went through the installation document linked above, where the installation topics are grouped in different categories, as in the agenda.
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- Bill: for the cooling system in the Hall if the hard piping is not ready we can still have a temporary solution using plastic pipes. However, we need chill water supply.  
  
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- Mechanical. Bill explained the way the detector rails will be installed: first in BCAL adjusting the two main rails to the nominal distance. Then the rails of the front installation cart will be adjusted and attached, and so on. The survey people will need space around the FDC and Bill was considering the possibility to remove the electronics racks. We think this should be done if absolutely necessary since the racks will be installed, powered, connected to ground, and this will delay the installation.
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- Expectations are to start the FDC installation sometimes in October. Before that we need to install the skin and do some small fixes on the FDC: fix the HV connectors, replace a couple of pre-amps. Need also to connect the cooling system between the packages.  
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- Electronics. According to Nick and Chris, most likely the modules will be tested in the crates and then the crates with the modules together installed in the racks, as in the original plan. This worked already for the FCAL, they just had to remove the power supplies while installing the crates. The LV and HV system will be installed in advance before the start of the FDC installation. They will be needed for testing.
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- Gas system. It's in production now. Some elements have been bought already. If the gas system is not ready when we start the installation, we will have to find a temporary solution: a dewar with Nitrogen, or better gas mixture.
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- Controls. Some minimal control will be needed during the installation. Dave will work on the codes for the chiller, and the gas system.
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- Testing. While connecting signal cables to the detector, we will test them by applying LV on the cards. For that we need the LV cables to be connected to the LV panels. After connecting all the cables to the detector we probably hav to disconnect the LV cables and re-route them, but this is to be seen. For the final testing we will use scintillators on the top and the bottom of the installation cart for triggering. We can try this in 126. Beni: for the DAQ there will be no problems to read 7 crates, what is needed for the test of one package.  
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== Engineering ==
 
== Engineering ==
  
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- Bill is working on the attachment to support the mesh, that is needed to avoid the four extra rails.  
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- Bill showed his new design of the mesh attachment using the main rails (drawings attached). Additional support at the end of the mesh, right between the CDC and FDC is needed; done with a stock T-shape Al profile (1/8"). Similar structure would be needed even with the old design using additional rails for the mesh attachment. The bearing for the mesh is glued to a holder. Same bearing is at the other (upstream) end of the mesh but it is removable. The drawings show also the plate connecting the packages and the grounding cable.
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== Electronics ==
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- Half of the signal cables have been labeled by the students. In fact, the plan was to label them as we connect them, but as soon as they are sorted by labels this is OK. The other half of the cable we may leave unlabeled, or label and sort them if there's time and people to do this. As for the LV cables all they have to be labeled, so far 3/4 are done.  
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- After testing the FDC with HV we will start working on the skin; the g10 sheets for that have been cut to the right sizes.  
  
 
== Tests at EEL126 ==
 
== Tests at EEL126 ==
  
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- The FDC packages are being flushed with gas, all four bubbling at 100ccpm total. Next week we will do the final test just by applying HV to each package.
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- We started applying HV on the FDC package by package; will keep the HV for at least 24 hours on each. For that the flow was increased from 100ccpm total to 200ccpm or 50ccpm per package. Gas mixture is 40/60. All the packages were bubbling already at 25ccpm per package.
  
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- We are testing now the spare package. Vlad did the grounding, signal and LV and HV connections to the top two cells. The max drift time for these cells is ~20usec and Beni made the corresponding corrections in the DAQ. He can read few thousand samples from the fADCs without a problem, but the event builder crashes above some event size when reading many modules.
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- While testing the top two cells of the spare package we had to increase the fADC samples up to 2500 resulting in a huge event size. This was a stress test for CODA: Beni, Elliot and others found a bug in CODA. Vlad is now analyzing the data from these cells at 40/60 Ar/CO2.
  
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- Vlad presented his results of analyzing the data from the top two cells with a scope at Blue Crab (talk attached above). He estimated the diffusion coefficient for 40/60 Ar/CO2 which turned out to be lower than the Garfield prediction at 100-200V/cm electric field. New results will come from the fADC data.

Latest revision as of 17:46, 30 August 2013

August 29, 2013 FDC meeting

Agenda

  1. Installation preparations [1]
  2. Engineering [2],[3],[4],[5] (Bill)
  3. Electronics (Chris, Nick)
  4. Tests at EEL126
    • Diffusion measurements [6] (Vlad)
  5. Other


Minutes

Participants: Bill, Eugene, Chris, Simon, Vlad, and Lubomir.

Installation preparations

- Bill: for the cooling system in the Hall if the hard piping is not ready we can still have a temporary solution using plastic pipes. However, we need chill water supply.

- Expectations are to start the FDC installation sometimes in October. Before that we need to install the skin and do some small fixes on the FDC: fix the HV connectors, replace a couple of pre-amps. Need also to connect the cooling system between the packages.

Engineering

- Bill showed his new design of the mesh attachment using the main rails (drawings attached). Additional support at the end of the mesh, right between the CDC and FDC is needed; done with a stock T-shape Al profile (1/8"). Similar structure would be needed even with the old design using additional rails for the mesh attachment. The bearing for the mesh is glued to a holder. Same bearing is at the other (upstream) end of the mesh but it is removable. The drawings show also the plate connecting the packages and the grounding cable.

- After testing the FDC with HV we will start working on the skin; the g10 sheets for that have been cut to the right sizes.

Tests at EEL126

- We started applying HV on the FDC package by package; will keep the HV for at least 24 hours on each. For that the flow was increased from 100ccpm total to 200ccpm or 50ccpm per package. Gas mixture is 40/60. All the packages were bubbling already at 25ccpm per package.

- While testing the top two cells of the spare package we had to increase the fADC samples up to 2500 resulting in a huge event size. This was a stress test for CODA: Beni, Elliot and others found a bug in CODA. Vlad is now analyzing the data from these cells at 40/60 Ar/CO2.

- Vlad presented his results of analyzing the data from the top two cells with a scope at Blue Crab (talk attached above). He estimated the diffusion coefficient for 40/60 Ar/CO2 which turned out to be lower than the Garfield prediction at 100-200V/cm electric field. New results will come from the fADC data.

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