Difference between revisions of "Minutes-9-27-2012"

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# Engineering (Bill)
 
# Engineering (Bill)
 
# Electronics (Chris, Nick)
 
# Electronics (Chris, Nick)
# Third package tests [https://halldweb1.jlab.org/elog-halld/FDC FDC E-log] (Beni)
+
# Third package tests [https://halldweb.jlab.org/elog-halld/FDC FDC E-log] (Beni)
 
# [http://www.jlab.org/Hall-D/detector/fdc/general/tdr.pdf TDR, pages 132-143] (Lubomir)
 
# [http://www.jlab.org/Hall-D/detector/fdc/general/tdr.pdf TDR, pages 132-143] (Lubomir)
 
# Other: plots for Eugene's talk  
 
# Other: plots for Eugene's talk  
#* packages: [http://www.jlab.org/Hall-D/detector/fdc/photographs/DSC07631.JPG #1],[http://www.jlab.org/Hall-D/detector/fdc/photographs/DSC07634.JPG #3], [http://www.jlab.org/Hall-D/detector/fdc/photographs/DSC07625.JPG #4]  
+
#* packages: [http://www.jlab.org/Hall-D/detector/fdc/photographs/DSC07631.JPG #1],[http://www.jlab.org/Hall-D/detector/fdc/photographs/DSC07634.JPG #3], [http://www.jlab.org/Hall-D/detector/fdc/photographs/DSC07625.JPG #4], [http://www.jlab.org/Hall-D/detector/fdc/photographs/WireFrameStacking.jpg wire frame stacking], [http://www.jlab.org/Hall-D/detector/fdc/photographs/cathode_tensioning.jpg cathode tensioning]  
#* corrosion: [http://www.jlab.org/Hall-D/detector/fdc/pictures/2012-07-23_11.21.18.jpg], [http://www.jlab.org/Hall-D/detector/fdc/corrosion/HIROX_EPDM-vchamb-humid-8-13-12/EPDM-8-13-12-smpl2-x50.jpg EPDM optical], [http://www.jlab.org/Hall-D/detector/fdc/corrosion/EPDM-vchamb-humid-8-13-12/EPDM-8-13-12-s1-x1K-area2.bmp EPDM spectrum], [http://www.jlab.org/Hall-D/detector/fdc/corrosion/VitonB/VitonB-x1K-area2.bmp Viton+Apiezon spectrum]
+
#* corrosion: [http://www.jlab.org/Hall-D/detector/fdc/pictures/2012-07-23_11.21.18.jpg damaged cathode],[http://www.jlab.org/Hall-D/detector/fdc/corrosion/HIROX_EPDM_Viton_comparison/epdm-level1-x2000-3d.jpg EPDM 3d optical] [http://www.jlab.org/Hall-D/detector/fdc/corrosion/HIROX_EPDM_Viton_comparison/epdm-level1-x350-trans.jpg EPDM optical transmitted light], [http://www.jlab.org/Hall-D/detector/fdc/corrosion/EPDM-vchamb-humid-8-13-12/EPDM-8-13-12-s1-x1K-area2.bmp EPDM spectrum], [http://www.jlab.org/Hall-D/detector/fdc/corrosion/VitonB/VitonB-x1K-area2.bmp Viton+Apiezon spectrum]
#* oxygen issue: [http://www.jlab.org/Hall-D/detector/fdc/photographs/O2problem_G10coating.jpg g10 coating], [http://www.jlab.org/Hall-D/detector/fdc/photographs/O2problem_Viton+vacuum_grease.jpg Viton+Apiezon reduces O2 from ~10,000ppm to <100ppm]
+
#* oxygen issue: [http://www.jlab.org/Hall-D/detector/fdc/photographs/O2problem_G10coating.jpg g10 coating], and [http://www.jlab.org/Hall-D/detector/fdc/photographs/O2problem_Viton+vacuum_grease.jpg Viton+Apiezon] reduce O2 from ~10,000ppm to <100ppm. The effect is visible comparing drift time spectra for the [http://www.jlab.org/Hall-D/detector/fdc/pictures/DrifTime_package1_run28.pdf first], and [http://www.jlab.org/Hall-D/detector/fdc/pictures/DriftTime_package3_run8.pdf second package]
 
#* test results:  [http://www.jlab.org/Hall-D/detector/fdc/pictures/WireResPrototype.jpg Wire Resolution from the full-scale prototype 40/60% Ar/CO%, 5*10^4 gas gain]
 
#* test results:  [http://www.jlab.org/Hall-D/detector/fdc/pictures/WireResPrototype.jpg Wire Resolution from the full-scale prototype 40/60% Ar/CO%, 5*10^4 gas gain]
#* Some pictures from the TDR: [https://halldsvn.jlab.org/repos/trunk/docs/tex-docs/src/apparatus/fdc/figs/tdr_fdc_4packages.jpg FDC system], [https://halldsvn.jlab.org/repos/trunk/docs/tex-docs/src/apparatus/fdc/figs/tdr_fdc_OneCell.jpg one cell elements], [https://halldsvn.jlab.org/repos/trunk/docs/tex-docs/src/apparatus/fdc/figs/CellSection.png cell section], [https://halldsvn.jlab.org/repos/trunk/docs/tex-docs/src/apparatus/fdc/figs/WireFrameLamination.png wire frame lamination, and other in that directory]
+
#* Some pictures from the TDR: [https://halldsvn.jlab.org/repos/trunk/docs/tex-docs/src/apparatus/fdc/figs/tdr_fdc_4packages.jpg FDC system], [https://halldsvn.jlab.org/repos/trunk/docs/tex-docs/src/apparatus/fdc/figs/tdr_fdc_OneCell.jpg one cell elements], [https://halldsvn.jlab.org/repos/trunk/docs/tex-docs/src/apparatus/fdc/figs/CellSection.png cell section], [https://halldsvn.jlab.org/repos/trunk/docs/tex-docs/src/apparatus/fdc/figs/WireFrameLamination.png wire frame lamination], and other in that directory
 
+
<!--
+
  
 
= Minutes =
 
= Minutes =
  
Participants: Bill, Dave, Glenn, Chris, Nick, Vlad, Simon, Beni, Eugene, and Lubomir
+
Participants: Eugene, Bill, Dave, Chris, Nick, Vlad, Simon, Beni, and Lubomir.
  
 
== Production ==
 
== Production ==
  
- Dave: we started working on two new cathodes, #72 and #73, using the last two sets of foils (new foils are coming November/December). Casey and Tina finished stringing today the new wire frame #29. There is a small delay with the new g10 wire frames (Vision Machine didn't have the vacuum pump), but they promised to have the first frame by Monday.  
+
- Dave: Tina is soldering wire frame #29. Mike is working on the PCB ring for #30. Five new g10 wire frames (we asked for four) were made by Vision machine, then we laminated the Rohacel rings and sent them back to Vision for the fly cut.
  
- The first three cells of package #1 were assembled Monday-Tuesday using the standard Viton+Apiezon technique. Since then it's being flushed with gas. Oxygen goes down very fast, now it's about 1000ppm and expect it to be ~300ppm tomorrow so Vlad will start testing the package.
+
- Vlad: testing the first three cells of package #1. The oxygen went down to 170ppm, we started flushing on Sunday. All the channels of the three cells were tested with a source and scope and are working fine. One pre-amp card was noisy, has to be replaced. Currents of the positive HV are higher in all the cells: 940nA, 82nA, and 350nA for cells 6,5, and 4 resp. This is to be compared to 149nA, 13nA, and 62nA we had in October 2011 when the same wire frames were in the second package: about a factor of 6! We will check the HV supply. 
 +
 
 +
- Lubomir: on Sunday Vlad found the gas bottle at Blue Crab (supplying gas to the first package and the testing vacuum chamber) empty due to high consumption of the testing chamber. The vacuum pump connected to the oxygen sensor through rotameter (~200ccpm) started sucking the gas from the chamber.
 +
The mineral oil in the bubbler filled completely the thin vertical tube (55mm corresponding to ~500Pa) but didn't go up in the spherical section of the bubbler. The top end window (2mil Mylar) had spherical shape meaning it was not touching the ground below it. After replacing the bottle on the same day, everything recovered. Vlad tested for leakage <5*10^-5 ml/sec about what was before. Beni is afraid that bending inward may cut the window if you have some epoxy sticking out of the frame. Bill: we need to find a way to turn off the pump when the pressure in the chamber drops. Lubomir: for now we can turn off the pump manually every evening, but at the same time have to reduce the flow in the chamber so that the pressure doesn't increase, which will result in inaccurate O2 measurements.
  
 
== Cathode corrosion ==
 
== Cathode corrosion ==
  
- We tried several techniques for covering the cathodes but all they had some problems:
+
- SEM analyses of Viton+Apiezon samples shown above: without cleaning, cleaned with alcohol, and with xylene (latests results). The carbon goes down with the cleaning and the rest is just copper. How to explain the dark color on the copper: either the method is not sensitive to what is there or (Bill) we still see the carbon that is difficult to clean. Olga will make pictures with the high-resolution optical microscope.  
 
+
# Kapton film + Hysol: many wrinkles, bubbles. Bill said he could do this using vacuum bagging, but should be done before the foils are stretched on the frame. 
+
# Kapton film + Apiezon: the O-ring made a channel into the grease and the surface outside of that channel was elevated due to the grease covered with the film. The O-ring compression was low, several leaks were found especially between the films. Still the oxygen went down to 75ppm for a cell with a cathode half covered with this method.
+
# Hysol only: the epoxy layer that was applied was too thin (<0.5mil) so that it doesn't protect the copper efficiently. That was tested in the vacuum chamber were we saw copper discoloration with the Vition+Apiezon+Hysol sample similar to the sample without Hysol. It will be difficult to apply thicker Hysol layer evenly. The oxygen went down to 75ppm (combined test with the above method).
+
# Kapton tape with acrylic adhesive: Hera-B outer tracker had Molter effect and studied all the materials. The SCOTCH 467MP tape that they used showed out-gassing.
+
 
+
- Latest pictures from the SEM analyses are linked above. They correspond to a Viton+Apizon sample with the right pressure (using spacer ring) inside the vacuum chamber filled with gas. The above pictures/spectral analyses correspond to the dark area at one side of the O-ring. With 1K magnification only copper and carbon are seen and some small traces of sulfur. When focusing on the small white particle from the first picture, one sees much more sulfur. The conclusion could be that with Viton we have significantly less sulfur which is not enough to destroy the copper surface as this is the case with EPDM. It can just create tiny holes through the copper that we have seen before using HIREX microscope with back-light. Based on this and on the failure of the above methods (so far) we decided to use the standard Viton+Apiezon method. In principle one could improve the above technologies and do more tests, but it will take significant efforts and time without being sure about their success.
+
 
+
- Vlad will continue with the corrosion tests in the vacuum chamber at several high temperatures so that we can extrapolate the results to room temperatures.
+
  
 
== Engineering ==
 
== Engineering ==
  
- Bill: soon will start working on the cooling cart. He explained the FDC fiducial scheme and the survey procedures. There will be four targets on each package visible from the front/back even when the detector is installed  and cabled. There will be a survey at Blue Crab of the packages as they are mounted on the cart, and also of the strong-back at the stringing table w.r.t the pins. The second survey will be done at the platform and the third one when the detector is installed.
+
- Bill made plots for the TDR, including the fiducialization that Simon needs also for the simulations.
  
 
== Electronics ==
 
== Electronics ==
  
- Nick and Chris populated one more PCB set to be used for wire frame #30. Nick gave Beni a LV module with distribution cards and cables enough for one package. The voltage at the LV source should be 6V to have at least 3V on each card (Nick). Eugene: one should measure the actual voltages at the cards and check if they will work when you remove one, two, or three pre-amps on the same cable.
+
- Eugene was interested about the work that remains to be done with the pre-amps, cabling, LV, HV for the FDC: ~90% (?) of the pre-maps passed the tests, most of the LV system is ready and have all the parts (Nick), some parts for the HV cabling still need to be ordered (Chris).
 +
 
 +
- Chris and Nick will populate the last two extra PCB sets during next weeks whenever they have time.
  
 
== Third package tests ==
 
== Third package tests ==
  
- Lubomir showed pictures (entry 79 in FDC ELOG) from fADC125 to which one wire, one top strip and one down strip cards are connected, each 24 channels with same color on the plots. Shown is a "typical" event with one wire channel (blue) and several top (red) and bottom (green) strips fired. The second picture shows the noise on the strips, < 200 fADC units which is ~15mV, and much less on the wires.
+
- Beni showing (entry 86) the wire efficiencies for the different planes: somewhat lower than before, ~95-96%. Beni explained the procedure which gives actually the upper limit for the efficiency (Eugene). Could be the changes in the atmospheric pressure, need first to find the plateau. There's some noise in the cell #3, few missing channels in #1 and #2 (pre-amp or chamber problem), and the problem with one -HV sector in #6 still there (can't go less than -150V, has to be -500V).
  
- Beni showed (entry 78) results for the strip resolution perpendicular to the wire, by reconstructing the position of one wire, which is about ~400 microns that corresponds to the resolution along the wire of ~100 microns. Lubomir has done similar studies (entry 77) but using different charge integration on the strips and also for all the wires. The resolutions vary with the HV and are similar to the results with the full scale prototype. The main conclusion is that one can get resolutions below 150 microns.
+
- Beni is taking data now with two fADC125 (three top and three bottom strip cards) and showed first results (entry 85) for the strip resolution on a wider portion of the chamber. The wire positions are reconstructed with a resolution of 500 to 600 microns (125-150 microns strip resolution along the wires). The mean values of the wire positions are used to find the distances between the wires: 10mm with 35microns sigma. The later to be compared with the ~25microns resolution measured with the laser sensor after the stringing. Beni once more explained the wire position reconstruction procedure.
  
 
== TDR ==
 
== TDR ==
  
- We are done with the draft TDR. Lubomir needs some numbers and re-formating of one picture from Bill. Eugene: maybe we should include some of the latest results and also explaining the algorithm used for the fADC data.
+
- We are done with the draft TDR. Everybody is encouraged to read/correct/comment on it before the collaboration meeting next week, then it will be checked it. Recently Bill put some missing information and new figures.
 +
 
 +
== Other ==
 +
 
 +
- Eugene needs FDC photos, plots  for a presentation that Mont asked for. All these are collected above.
  
-->
+
- No meeting next week due to the collaboration meeting.

Latest revision as of 14:52, 31 March 2015

September 27, 2012 FDC meeting

Agenda

  1. Production Construction Tracking (Dave)
    • First package tests (Vlad)
  2. Cathode corrosion
  3. Engineering (Bill)
  4. Electronics (Chris, Nick)
  5. Third package tests FDC E-log (Beni)
  6. TDR, pages 132-143 (Lubomir)
  7. Other: plots for Eugene's talk

Minutes

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

Production

- Dave: Tina is soldering wire frame #29. Mike is working on the PCB ring for #30. Five new g10 wire frames (we asked for four) were made by Vision machine, then we laminated the Rohacel rings and sent them back to Vision for the fly cut.

- Vlad: testing the first three cells of package #1. The oxygen went down to 170ppm, we started flushing on Sunday. All the channels of the three cells were tested with a source and scope and are working fine. One pre-amp card was noisy, has to be replaced. Currents of the positive HV are higher in all the cells: 940nA, 82nA, and 350nA for cells 6,5, and 4 resp. This is to be compared to 149nA, 13nA, and 62nA we had in October 2011 when the same wire frames were in the second package: about a factor of 6! We will check the HV supply.

- Lubomir: on Sunday Vlad found the gas bottle at Blue Crab (supplying gas to the first package and the testing vacuum chamber) empty due to high consumption of the testing chamber. The vacuum pump connected to the oxygen sensor through rotameter (~200ccpm) started sucking the gas from the chamber. The mineral oil in the bubbler filled completely the thin vertical tube (55mm corresponding to ~500Pa) but didn't go up in the spherical section of the bubbler. The top end window (2mil Mylar) had spherical shape meaning it was not touching the ground below it. After replacing the bottle on the same day, everything recovered. Vlad tested for leakage <5*10^-5 ml/sec about what was before. Beni is afraid that bending inward may cut the window if you have some epoxy sticking out of the frame. Bill: we need to find a way to turn off the pump when the pressure in the chamber drops. Lubomir: for now we can turn off the pump manually every evening, but at the same time have to reduce the flow in the chamber so that the pressure doesn't increase, which will result in inaccurate O2 measurements.

Cathode corrosion

- SEM analyses of Viton+Apiezon samples shown above: without cleaning, cleaned with alcohol, and with xylene (latests results). The carbon goes down with the cleaning and the rest is just copper. How to explain the dark color on the copper: either the method is not sensitive to what is there or (Bill) we still see the carbon that is difficult to clean. Olga will make pictures with the high-resolution optical microscope.

Engineering

- Bill made plots for the TDR, including the fiducialization that Simon needs also for the simulations.

Electronics

- Eugene was interested about the work that remains to be done with the pre-amps, cabling, LV, HV for the FDC: ~90% (?) of the pre-maps passed the tests, most of the LV system is ready and have all the parts (Nick), some parts for the HV cabling still need to be ordered (Chris).

- Chris and Nick will populate the last two extra PCB sets during next weeks whenever they have time.

Third package tests

- Beni showing (entry 86) the wire efficiencies for the different planes: somewhat lower than before, ~95-96%. Beni explained the procedure which gives actually the upper limit for the efficiency (Eugene). Could be the changes in the atmospheric pressure, need first to find the plateau. There's some noise in the cell #3, few missing channels in #1 and #2 (pre-amp or chamber problem), and the problem with one -HV sector in #6 still there (can't go less than -150V, has to be -500V).

- Beni is taking data now with two fADC125 (three top and three bottom strip cards) and showed first results (entry 85) for the strip resolution on a wider portion of the chamber. The wire positions are reconstructed with a resolution of 500 to 600 microns (125-150 microns strip resolution along the wires). The mean values of the wire positions are used to find the distances between the wires: 10mm with 35microns sigma. The later to be compared with the ~25microns resolution measured with the laser sensor after the stringing. Beni once more explained the wire position reconstruction procedure.

TDR

- We are done with the draft TDR. Everybody is encouraged to read/correct/comment on it before the collaboration meeting next week, then it will be checked it. Recently Bill put some missing information and new figures.

Other

- Eugene needs FDC photos, plots for a presentation that Mont asked for. All these are collected above.

- No meeting next week due to the collaboration meeting.