Difference between revisions of "Minutes-11-21-2013"

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= Minutes =
 
= Minutes =
  
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Participants: Eugene, Bill, Dave, Nick, Chris, Simon, Vlad, Beni, and Lubomir.
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Participants: Bill, Dave, Nick, Chris, Simon, Vlad, Beni, Elton, Hovanes (for the LV control discussions) and Lubomir.
  
 
== Installation ==
 
== Installation ==
  
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- FDC was moved to the floor on Monday. Bill, Casey, and Dave glued the 16 reflectors to the gussets of the packages (four per package). The survey group started working on the new targets yesterday and they are working now. Preliminary findings: if looking along z they found distance between the first and last package to the be the same as the measured one within 0.5mm (measured with measuring tape?). However, they found that this is no longer the case if you look at some angle (w.r.t. the normal of the reflectors), as Eugene expected. They are now trying to find what is the angle range that is acceptable. They were also instructed to redo all the surveys they did before: the four SMR holders on each package and the flatness measurements.  
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- Dave: right now techs are working on the mesh, it will be finished by the end of the day or tomorrow. Tom prefers only after that the FDC to be moved on the platform (today or tomorrow morning). In the mean time Tom and Dave tested the cooling system for leakage with He at 10-15 psi using the big testing unit used for the magnet. A leak was found in the connection of one of the manifolds and Casey fixed it. Dave wade the houses and the fittings needed to connect the FDC to the chiller once it is on the platform. As of yesterday we have also chilled water and the connections to the chiller are ready.
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- We discussed details how to connect/bundle/route the LV cables. The cables will be laying on the floor all over the platform for some time and we want to make sure the cables and especially the connectors are at a safe place. Most likely we have to run the individual cables around the pair spectrometer magnet (these are 18m long cables) and then bundle them in groups of 8 or 9. The exact procedure will be clear once we start cabling. We should have then the bundles routed so that they don't interfere with the signal cables. We want to use regular cable ties at least close to the connectors (for strain relief), but then along the mesh we cab use Velcro ties (Nick has now narrower ties with bigger friction).  
  
 
== Engineering ==
 
== Engineering ==
  
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- We discussed again the previous survey results. As stated at the last meeting, Bill found that the nominal thickness of the first package is very close to the measured value from the flatness data. However, when he looked at the other packages he found that 4 is OK, but 2 and 3 are not: ~0.5mm discrepancy. In addition there's a discrepancy for the position of the 4th package as measured with the four SMR holders between the Blue Crab and the first survey in the Hall. That's why they will redo all the measurements now.
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- The raw data from the last survey is now available (attached above, all the numbers are in meters). At a first look the thickness of the packages are OK, +/- 0.3mm from the nominal, but this require more studies. The main question was if the prisms can be used to measure the z positions with a few hundred microns resolution, but these measurements are not enough to make a conclusion.  Still one can see that the z positions of the prisms at one package vary by up to 6mm but Bill says this is possible given the way the prisms are glued to the gussets. If one
  
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- Bill: we have all the parts to connect the cooling system. Bill will check if the chilled water is ready, and what else remains to be done. We discussed if we want to do the cooling system checks down on the floor, or up on the platform. Most of the people preferred to do this on the platform (the disadvantage: more difficult to check the manifolds, tubing at the bottom). Tom had an idea to have a long tube that connects the FDC on the platform to the chiller through the magnet which will be the final connection, but Bill prefers to place the chiller at the upstream side with a short tube to the FDC as a temporary connection.
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- Once the mesh is installed Bill wants to make sure CDC will fit. A wooden disk can be used to check this or the CDC mock-up but it will need some work. He thinks at least initially the cables shouldn't be connected to the mesh very tightly so that we have the freedom to shape the mesh if it is not cylindrical.
  
 
== Electronics ==
 
== Electronics ==
  
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- Nick: all the cables have been nicely stored and organized in the cave behind the platform. The LV system is now connected. The two crates (fADC125 and F1TDC) that will be used for testing were mounted on the rack. The main issue now is the power for the crates. It turned out there's no 208V two phases on the transformer, that is the required power for the crates. In principle we can use 110V (but powering only some of the modules!), but it turned out there's only 15A and the crate requires 20A. Tom is looking now for a solution.
 
  
 
== Mini-DAQ ==
 
== Mini-DAQ ==

Revision as of 16:51, 21 November 2013

November 21, 2013 FDC meeting

Agenda

  1. Installation [1] (all)
  2. Engineering (Bill)
  3. Electronics (Chris, Nick)
  4. Mini-DAQ for FDC tests [3] (Beni)
  5. Other


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