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

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(Created page with "November 21, 2013 FDC meeting = Agenda = # Installation [http://www.jlab.org/Hall-D/detector/fdc/installation/FDC_installation.pdf] (all) # Engineering (Bill) #* FDC survey # El...")
 
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# Installation [http://www.jlab.org/Hall-D/detector/fdc/installation/FDC_installation.pdf] (all)
 
# Installation [http://www.jlab.org/Hall-D/detector/fdc/installation/FDC_installation.pdf] (all)
 
# Engineering (Bill)
 
# Engineering (Bill)
−
#* FDC survey
+
#* FDC survey[http://www.jlab.org/Hall-D/detector/fdc/installation/DT_D1519.xlsx]
 
# Electronics (Chris, Nick)
 
# Electronics (Chris, Nick)
−
# Mini-DAQ for FDC tests [https://halldweb1.jlab.org/wiki/index.php/First_Tests_in_Hall-D] (Beni)
+
# Mini-DAQ for FDC tests [https://halldweb.jlab.org/wiki/index.php/First_Tests_in_Hall-D] (Beni)
 
# Other
 
# Other
−
 
−
<!--
 
  
 
= Minutes =
 
= Minutes =
  
−
Participants: Eugene, Bill, Dave, Nick, Chris, Simon, Vlad, Beni, and Lubomir.
+
Participants: Bill, Dave, Nick, Chris, Simon, Vlad, Beni, Elton, Hovanes (for the LV control discussions) and Lubomir.
  
 
== Installation ==
 
== Installation ==
  
−
- 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.  
+
- 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 made 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.
 +
 
 +
- 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 ==
  
−
- 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.
+
- The raw data from the last survey is now available (attached above, all the numbers are in meters). At a first look the thicknesses of the packages are OK, +/- 0.3mm from the nominal, but this requires more studies. The main question was if the prisms can be used to measure the z positions with a few hundred microns resolution, but the data we have 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. The distances between the packages from the SMR and from the prism measurements are similar (up to few mm) for the package #1-#2 and #2-#3. There's about 4cm difference for the distance between #3 and #4, but there one has to take into account the SMR holder sizes. Certainly all this require careful analysis.
  
−
- 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.
+
- Important is that the prisms were survey from a big distance of 6-8 m, chosen by the survey people to have very similar angles w.r.t. prism surfaces. However we will not have that space between the FDC in the magnet and the FCAL in the current position. Bill will talk to the survey group to find if they have estimated the effect of distance to the targets. After the meeting Bill talked to Jim Dahlberg: the prisms are accurate at 100 micron level if viewed at +/-5cm transversely at 3m from the target; at +/- 10cm the accuracy is 170 microns.  
 +
 
 +
- Once the mesh is installed Bill wants to make sure CDC will fit. A wooden disk with bearings inserted in the rails will be used for that. The disk will be inside the mesh while cabling the FDC so that we can do checks from time to time. Bill thinks that 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 ==
  
−
- 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.
+
- We have everything needed to start the cabling. According to Nick with the temporary 120V/20A power we can't have more than 4 LV modules in the crate, so we will be doing the LV tests in groups of several modules.  
  
 
== Mini-DAQ ==
 
== Mini-DAQ ==
  
−
- Beni has prepared a mini-DAQ system to test the cable connections while cabling. The system is now on "wilma" computer and has been tested there. See the link above for the full description of the system, as prepared by Beni. The system reads one module fADC125 and plots the pedestals; the widths will indicate proper connections. For the F1TDC the system sends pulses to the front of the pre-amp and gets back the timings. It's not a problem to install run the system from the new computer that will be on the platform "joebesser". As for the LV and HV system, Hovanes will be working on them; the systems are supposed to be ready but have not been tested with the real modules. In any case we can use Beni's LV system at the beginning to test the LV connections.
+
- Beni installed the computer "joebesser" on the platform close to the north racks. Hovanes set-up and tested the LV control system that can be used from "joebesser" under "halld" account. Since we have to change the LV module configuration and this requires ioc reboot, Hovanes gave us (at least temporary) privileges to do this.
−
 
+
−
== Full electronics test analyses ==
+
−
 
+
−
- Lubomir estimated of the wire resolution (see Entry 122 in the Elog linked above) using external tracking (IU chambers). Previous attempt to do this with package #3 (partial electronics) failed. Lubomir and Beni fixed a bug in the IU chamber configuration and the position resolution was improved from ~6mm to ~2.7mm. We use two cells with parallel wires, #1 and #4, take the difference between the track angles reconstructed from IU chambers on a 154cm base and the two cells, then multiply it by the distance between the cells (6.45 cm). This is a measure of the resolution of the two cells. The first plot shows the resolution of one cell (~200 microns in 1-4 mm distance-to-the-wire region), but it has to be corrected by the IU chamber contribution estimated to be ~110 microns (with big uncertainty!).
+
−
 
+
−
-->
+

Latest revision as of 00:48, 1 April 2015

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

Minutes

Participants: Bill, Dave, Nick, Chris, Simon, Vlad, Beni, Elton, Hovanes (for the LV control discussions) and Lubomir.

Installation

- 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 made 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.

- 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

- The raw data from the last survey is now available (attached above, all the numbers are in meters). At a first look the thicknesses of the packages are OK, +/- 0.3mm from the nominal, but this requires more studies. The main question was if the prisms can be used to measure the z positions with a few hundred microns resolution, but the data we have 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. The distances between the packages from the SMR and from the prism measurements are similar (up to few mm) for the package #1-#2 and #2-#3. There's about 4cm difference for the distance between #3 and #4, but there one has to take into account the SMR holder sizes. Certainly all this require careful analysis.

- Important is that the prisms were survey from a big distance of 6-8 m, chosen by the survey people to have very similar angles w.r.t. prism surfaces. However we will not have that space between the FDC in the magnet and the FCAL in the current position. Bill will talk to the survey group to find if they have estimated the effect of distance to the targets. After the meeting Bill talked to Jim Dahlberg: the prisms are accurate at 100 micron level if viewed at +/-5cm transversely at 3m from the target; at +/- 10cm the accuracy is 170 microns.

- Once the mesh is installed Bill wants to make sure CDC will fit. A wooden disk with bearings inserted in the rails will be used for that. The disk will be inside the mesh while cabling the FDC so that we can do checks from time to time. Bill thinks that 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

- We have everything needed to start the cabling. According to Nick with the temporary 120V/20A power we can't have more than 4 LV modules in the crate, so we will be doing the LV tests in groups of several modules.

Mini-DAQ

- Beni installed the computer "joebesser" on the platform close to the north racks. Hovanes set-up and tested the LV control system that can be used from "joebesser" under "halld" account. Since we have to change the LV module configuration and this requires ioc reboot, Hovanes gave us (at least temporary) privileges to do this.

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