Difference between revisions of "Minutes-11-18-2010"

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# Production (David)
 
# Production (David)
 
#* Blue Crab status [http://www.jlab.org/Hall-D/detector/fdc/production/BCplan.pdf sketch]
 
#* Blue Crab status [http://www.jlab.org/Hall-D/detector/fdc/production/BCplan.pdf sketch]
−
#* Frame lamination
+
#* Frame lamination  
−
#* FDC change request discussion   
+
#* FDC change request discussion  [http://www.jlab.org/Hall-D/detector/fdc/budget/FDC_budget.pdf proposed FDC production budget]
 
# Electronics (Fernando, Chris, Roger)
 
# Electronics (Fernando, Chris, Roger)
 
#* PCB status
 
#* PCB status
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# Other
 
# Other
  
−
<!--
 
 
= Minutes =
 
= Minutes =
−
Participants: Eugene, Fernando, Bill, Casey, Mark, Chris, Roger, Al, Simon, Beni, and Lubomir.
+
Participants: Bill, Fernando, Glenn, Eugene, Dave, Al, Chris, Roger, Simon, and Lubomir.
  
 
== Production ==
 
== Production ==
  
−
- They are going to install phones and work on the Internet today at Blue Crab. We can now use heaters at low temperatures; must be above 60degF for gluing.  
+
- Blue Crab status: the granite tables and other stuff was moved to make space for the clean room construction. We decided to keep 2 or 3 tables inside the office to be used for gluing the PCB rings and their lamination. Dave found office furniture that we can storage in Blue Crab as long as the accelerator people do not complain.  
  
−
- By next Wednesday expect to have all the wire frames laminated. 18 frames came back from Vision machine after fly cut. They started there also the cathode frame production.
+
- All wire frames laminated with Rohacell. Most of them are fly cut and stored in our machine shop; we decided to move them to 126 to make sure they are not exposed to high humidity. Four cathode frames are ready, but Vision Machine had problems with the milling machine and the production will be delayed (this will not affect the production at all). The next step is to glue and laminate the PCBs.
  
−
- Dave made the next version of the production plan. We start production in March 2011, the first package will be ready by September 2011 and then every ~4 months we plan to have a new package. According to the plan we will produce chamber by chamber serially, so that we can test them at the same time.  
+
- As requested by Eugene we have updated the FDC production budget linked above; it is needed urgently for the change request. Everybody is encouraged to look at it and make corrections if needed asap.  
  
 
== Electronics ==
 
== Electronics ==
  
−
- Chris received all the populated PCBs. The inspection showed that the packaging was not done correctly (as for the first article) and as a result 8 PCBs (3+3+2 of different types) had broken tips up to 1.5". Bill thinks that this is not crucial and one should be able to glue the PCBs together. The main problem is that the PCBs have much more flux than the first article PCBs; the latter also were not acceptable. Fernando discussed the issue with the company and we will ship all the PCBs back for cleaning. In addition Chris found some other problems that are not crucial (Fernando). Find many pictures from the PCB inspection at  M:\halld-electronics\Documents\FDC\Populated FDC First Articles on Windows, or at the /group/halld-electronics/Documents/FDC/Populated FDC First Articles on linux.   
+
- Chris sent the PCBs back to the company for cleaning. Only the first article PCBs (two of each) are here and Chris is cleaning them at 126. They will be ready for gluing and laminating by the beginning of the next week. We have to test all the PCBs with HV applying 2500V, before using them in the production.   
−
 
+
−
- Roger received the Gerber files from Allflex adjusted to the production, for final approval. Bill and Fernando looked at them and agreed. The first cathode foils will be produced in the week of 11/29-12/3. The rigid-flex contract was awarded with a company also near Minneapolis. We will have the first article also by the end of the month.
+
- Roger: Allflex confirmed they will start the cathode foil production the last week of November. After some iterations with the Gerber files for the rigid-flexes we also expect their production to start at the end of November, so that at the beginning of December we will have the first article: 25 rigid-flexes.
−
 
+
These will be used also to exercise the soldering; for that we have to cut the connectors on the side of the cathode foils during their inspection.  
−
- Cathode foil inspection: George Jacob suggested moving the two tables inside the Hall B clean area in the evening before the week of 12/6-12/10, using the roll-up door, so that the particle count goes down by 12/6. We have one 2x5' table and need to find another one. Fernando: need to check the connectivity (resistance if measurable) for each strip, but also between the strips; the latter was an issue before. Fernando will send David the QA procedure for the cathode foils and the PCBs.
+
 
   
 
   
 
== Engineering ==
 
== Engineering ==
  
−
- Bill showed his model of the wire stringing table (linked above). He made improvements in the height adjustment of the strongback. The movement system will be attached to the sides of the table and movable over the chamber. There were different suggestions how to install it so that it's not obstructive when stringing. We discussed also how to calibrate/set starting point for the position measurements.
+
- Wire stringing: Bill ordered the parts for the motion system frame. The wheels on the granite table have to be installed better before the other installations.
  
−
- Stepper motor controller: Beni tried to use JLab controllers from the target group to control the motor. It works only without using the encoder. Therefore, we will order a new controller from "Cross-Automation" for ~$3k. As for the software, it comes with low level, AcroBasic, and high level, AcrView software. There are drivers also for LabView (Dave) and we will ask for help from somebody in the lab familiar with LabView.  
+
- Motion system: waiting for the Parker controller. Fernando will send Bill the link for the laser sensor with 200kHz sampling. Fernando tried using a generator and a speaker to vibrate the wires but the amplitude was very small. For now we will use the "scrubbing" method, later with the real wires we can try again using better speaker system.  
  
−
- Using laser sensor for position measurement: The laser sensor we use for foil tension measurements has low sampling rate (~1kHz) which is not good enough to measure frequenses of the order of several hundred Hz (Fernando). We will try with a free sample 200kHz sensor (Bill) and if it works for us we will buy it.
+
- Bill ordered the second foil tensioner. Al is working on the heating device to be used for the 3M conductive tape.  
  
 
== Full-scale prototype tests ==
 
== Full-scale prototype tests ==
  
−
- Beni is using now both, fADC and discriminator cards, for timing at different places on the top and middle chamber. He will be able to compare directly their performance, but has some software problems.
+
- Beni compared experimentally the wire resolution when using F1TDC (with discriminator card) and fADC125: ~180microns for F1TDC and ~250microns for fADC125 (page 542).
  
−
- Fernando found that one of the connectors for the discriminator card in the middle chamber is noisy. Beni: checking the connectors should be included in the QA procedure.
+
- Lubomir simulated with Garfield the drift time spectra for distances to the wire from 0 to 5mm with a step of 200um (page 541). Simon used these in his MC simulations (page 543). The Garfield model was calibrated using experimental data with 55Fe source.  
  
−
- Lubomir studied the cathode resolution as function of the strip multiplicity for different thresholds (page 539) using cosmics data. The strip multiplicity in the Simon's MC simulations (page 537) of ~4.5 corresponds to about 15mV threshold at 2 10^5 gas gain. At 40mV threshold the mean multiplicity goes down to ~3 but the resolution gets worse. The GlueX event size is dominated by the size of the data from the FDC cathodes. Therefore, this is a trade between resolution and event size.
+
- Lubomir investigated the relations between the strip multiplicity (that defines practically the event size), strip resolution, and reconstruction efficiency (page 540) for different thresholds, gas gains, and gas mixtures using cosmics. With a gas gain of 10^5, one can have ~3.5 strip multiplicity, resolution of ~150um at sufficiently high efficiency.
−
-->
+

Latest revision as of 16:47, 19 November 2010

November 18, 2010 FDC meeting

Tentative Agenda

  1. Production (David)
  2. Electronics (Fernando, Chris, Roger)
    • PCB status
    • Other
    • Cathode foil and rigid-flex production
  3. Engineering (Bill, David, Beni)
    • Wire stringing status model.
    • Other
  4. Full-scale prototype tests
  5. Other

Minutes

Participants: Bill, Fernando, Glenn, Eugene, Dave, Al, Chris, Roger, Simon, and Lubomir.

Production

- Blue Crab status: the granite tables and other stuff was moved to make space for the clean room construction. We decided to keep 2 or 3 tables inside the office to be used for gluing the PCB rings and their lamination. Dave found office furniture that we can storage in Blue Crab as long as the accelerator people do not complain.

- All wire frames laminated with Rohacell. Most of them are fly cut and stored in our machine shop; we decided to move them to 126 to make sure they are not exposed to high humidity. Four cathode frames are ready, but Vision Machine had problems with the milling machine and the production will be delayed (this will not affect the production at all). The next step is to glue and laminate the PCBs.

- As requested by Eugene we have updated the FDC production budget linked above; it is needed urgently for the change request. Everybody is encouraged to look at it and make corrections if needed asap.

Electronics

- Chris sent the PCBs back to the company for cleaning. Only the first article PCBs (two of each) are here and Chris is cleaning them at 126. They will be ready for gluing and laminating by the beginning of the next week. We have to test all the PCBs with HV applying 2500V, before using them in the production.

- Roger: Allflex confirmed they will start the cathode foil production the last week of November. After some iterations with the Gerber files for the rigid-flexes we also expect their production to start at the end of November, so that at the beginning of December we will have the first article: 25 rigid-flexes. These will be used also to exercise the soldering; for that we have to cut the connectors on the side of the cathode foils during their inspection.

Engineering

- Wire stringing: Bill ordered the parts for the motion system frame. The wheels on the granite table have to be installed better before the other installations.

- Motion system: waiting for the Parker controller. Fernando will send Bill the link for the laser sensor with 200kHz sampling. Fernando tried using a generator and a speaker to vibrate the wires but the amplitude was very small. For now we will use the "scrubbing" method, later with the real wires we can try again using better speaker system.

- Bill ordered the second foil tensioner. Al is working on the heating device to be used for the 3M conductive tape.

Full-scale prototype tests

- Beni compared experimentally the wire resolution when using F1TDC (with discriminator card) and fADC125: ~180microns for F1TDC and ~250microns for fADC125 (page 542).

- Lubomir simulated with Garfield the drift time spectra for distances to the wire from 0 to 5mm with a step of 200um (page 541). Simon used these in his MC simulations (page 543). The Garfield model was calibrated using experimental data with 55Fe source.

- Lubomir investigated the relations between the strip multiplicity (that defines practically the event size), strip resolution, and reconstruction efficiency (page 540) for different thresholds, gas gains, and gas mixtures using cosmics. With a gas gain of 10^5, one can have ~3.5 strip multiplicity, resolution of ~150um at sufficiently high efficiency.

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