Difference between revisions of "Minutes-4-14-2011"

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# Electronics  
 
# Electronics  
 
#* Status (Fernando,Chris)
 
#* Status (Fernando,Chris)
−
#* fADC125 requirements  
+
#* fADC125 [http://www.jlab.org/Hall-D/detector/fdc/electronics/FDC_electronics_req.pdf requirements]
 
#* Cathode foil inspection
 
#* Cathode foil inspection
 
# Engineering
 
# Engineering
−
#* Satus (Bill)
+
#* Status (Bill)
 
#* Radiation tests with conductive tape (Lubomir)
 
#* Radiation tests with conductive tape (Lubomir)
 
# Chamber testing (Lubomir)  
 
# Chamber testing (Lubomir)  
 
# Other
 
# Other
−
 
−
<!--
 
  
 
= Minutes =
 
= Minutes =
  
−
Participants: Bill, Eugene, Dave, Chris, Roger, Fernando, Simon, and Lubomir.
+
Participants: Eugene, Bill, Dave, Chris, Simon, and Lubomir.
  
 
== Production ==
 
== Production ==
  
−
- Just before the meeting the review committee sent us their final report, linked above to the agenda. Eugene commented on it: there are no show-stoppers and the FDC production can continue. There are no recommendations, just findings and suggestions on which we may answer later. The main suggestion is to test the z-axis conductive tape technique for gluing the rigid-flex assemblies.  They suggest to study the radiation damages and also to continue with the conventional testing in longer term. Even if it turns out later during the production that there are problems with this technique, it will be possible to re-solder the rigid-flexes using standard soldering technique. The committee also suggested to work on the packaging and storing of the materials and assemblies. There were some healthy concerns related to the air quality (due to the use of chemicals), HV as used for testing the chambers and also ergonomic conditions. Overall the conclusions of the committee are very positive and Eugene thanked to the people involved in the FDC review.
+
- 11 cathodes were inspected so far; one panel was damaged by us because of incorrect packaging.
  
−
- Dave: the production actually started already on April 1st with making one cathode foil that will be used for the first chamber. The test cathode was glued to the frame but some additional tooling is needed to cut the foil. In the mean time we will tension the first production cathode foil. Also, the first production PCB ring was glued. Now we have the tools to trim the Rohacell on wire frames. For the start of the production we will use the solder wire from UVA, even it's thicker (~0.7mm) than what we have ordered.
+
- the first production cathode was glued tensioned and the frame was glued to it; cutting the flaps and the holes is next. Some of these procedures still require signatures. Cutting the second production cathode started with problems with the cutter. Bill thinks it is the granite surface that damages the blades. Using harder blade and treating the granite surface must help. Bill also made modifications to the cutter to prevent wobbling of the blade.
  
−
== Electronics ==
+
- a PCB ring was glued to be used for the first production wire frame. Tests with light show the surface at the seams is not perfectly flat. Anatoly will work on this. Next steps: trimming the Rohacell OD on the wire frame and laminating the PCB ring. We will accelerate this so that we can work on the wire frame in parallel with the cathodes. Bill asked if it will be acceptable to use parafin to cover some parts of the Rohacell OD that is needed for the ultrasonic cleaning. Lubomir will investigate this.
  
−
- Fernando: ASIC contract was awarded. Still waiting from the CDC people to confirm the parameters of the pre-amps and the FADC125 shaping. If needed one can modify the attenuation on their HV boards without changing the parameters of the pre-amps and fADC125. We already confirmed that the parameters are OK for the FDC.
+
- Dave is working on the paperwork for making holes in the clean room. We decided to have 4 holes: two in the cathode area and one in each of the small rooms. The holes will be used for nitrogen, compressed air and chamber gas mixture supply.
 +
 +
- We received the solder wire (0.65mm) from UVA that we will use for wire soldering at the beginning. Al has progress with the software (for the Parker controller) used to find the wire position.
 +
 
 +
== Electronics ==
  
−
- Rigid-flex assemblies: we received 480 recently and expect the last 135 in May. Fernando and Chris wanted to know how to proceed with the stuffing: to tin or not to tin the contacts. Tinning is needed if the conductive tape doesn't work and we have to solder. So far testing electrically the conductive tape we haven't seen any differences between the tinned and not tinned samples. Still mechanical tests with tinned samples have not been done yet. For now, we decided to order 50 rigid-flexes tinned and 50 not tinned so that we can continue with the production. The price will be higher by a few hundred $ due to the set-up fees (Eugene agreed). Depending on the results we will decide what to do with the rest of the rigid-flexes.
+
- Chris: nothing new, waiting for quotation for the rigid-flex tinning.  
  
−
- Last week we received the first two sets of foils from the mass production that were already inspected. The foils look better that those from the first article; still visible are imprints of the rollers on the foils but these will disappear after tensioning. Another two sets just arrived. Roger asked to put the invoice number together with the results of the inspection in a spreadsheet so that he can handle the payments. Regarding the storage of the foils, so far we leave them flat on a table after the inspection and Dave ordered shelvings for that, but Fernando and Roger are concerned with possible corrosion. We decided to try with one set to roll it back in the original packing which is a more compact way of storing.
+
- Yesterday at the tracking meeting we discussed possible modifications for the fADC125: increase of the gain to cover the whole 12 bit range that was requested by the CDC people. This is not acceptable for the FDC and as seen in the document linked above we are happy with the current version. Eugene insisted that we don't want to have two fADC125 versions which will delay their production and increase the costs, and that this will not solve the problem with the dynamic range. Now they are considering modification of the termination of the CDC pre-amps. In any case for us the fADC125 will not change.
−
 
+
 
== Engineering ==
 
== Engineering ==
  
−
- Conductive tape tests. Bill did mechanical tests: to peel off the conductive tape one needs from 80g on the edge of the tape to about 130g in the middle. One of our techs tried it already pulling by hand one side of a sample and peeled it off easily. Bill will improve the tooling: wider and longer shoe, higher temperature (up to 350degF, according to Fernando solder melts above 400degF) and wider conductive tape. In addition if we have to, we can tape the contact with Kapton tape on the top after gluing.  We also put two samples in liquid nitrogen and they are OK electrically. Bill will test those mechanically. Dave will do test also with heating up to ~80degC. Lubomir placed four samples in Hall C to study the radiation hardness as suggested by the review committee. We expect to have results from this test in a month; the first samples will have enough radiation in a week but taking them out of the Hall and reading the dosimeters will take time. Since so far there are no problems (that are not solvable) with the conductive tape we decided to start the production using this technique.
+
- Bill is working on the package assembly jig plate and placed orders for: the new 3M tape gluing tool, cutter modifications, and spacer ring needed for the end window gluing.  
  
−
- Bill is working on different tools: the heater for the conductive tape, the new jig table to be used for the package assembly, improving the foil cutter and other.  
+
- One rigid-flex sample set (two samples) that had higher radiation exposure was taken out of Hall C yesterday. It showed some residual radiation but we still were allowed to have it in 126. The two samples passed the electrical tests successfully. Bill had an idea how to do the mechanical tests: by gluing a Kapton piece on the top of the rigid-flex.
  
 
== Chamber testing ==
 
== Chamber testing ==
  
−
- Simon showed results from his analyses of the cosmics data with fADC. First (page 554) it appears that the wires as "seen" by the strips are at an angle systematically: ~2mm over the length of the wire. So far the explanation is that the strip pitch might be different due to the cathode tensioning. To calibrate the strips (page 555) using the fact that the charges on the top and bottom strips are the same, first he makes "sagging" correction and then finds the calibration constants for each channel. After the first iteration, the resolution improves by ~10%. The fraction of the charge in the strip with the max signal is about 50% of the total charge (page 556).
+
- The prototype is now in vertical position. To test it, we used 55Fe source triggering with one of the wires. Data was taken, but no results yet due to some software problem; waiting for Beni to fix it.  
  
−
-->
+
- At the end we also discussed possible ways to replace the radioactive sources when testing the chambers at Blue Crab. Possible ways: using nitrogen laser (needs special gas mixture), X-ray tube like TV tube. We expect safety issues like with the use of radioactive sources at Blue Crab, so we are giving up unless it's absolutely necessary to have some kind of source there.

Latest revision as of 16:54, 14 April 2011

April 14, 2011 FDC meeting

Agenda

  1. Production status (Dave)
  2. Electronics
    • Status (Fernando,Chris)
    • fADC125 requirements
    • Cathode foil inspection
  3. Engineering
    • Status (Bill)
    • Radiation tests with conductive tape (Lubomir)
  4. Chamber testing (Lubomir)
  5. Other

Minutes

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

Production

- 11 cathodes were inspected so far; one panel was damaged by us because of incorrect packaging.

- the first production cathode was glued tensioned and the frame was glued to it; cutting the flaps and the holes is next. Some of these procedures still require signatures. Cutting the second production cathode started with problems with the cutter. Bill thinks it is the granite surface that damages the blades. Using harder blade and treating the granite surface must help. Bill also made modifications to the cutter to prevent wobbling of the blade.

- a PCB ring was glued to be used for the first production wire frame. Tests with light show the surface at the seams is not perfectly flat. Anatoly will work on this. Next steps: trimming the Rohacell OD on the wire frame and laminating the PCB ring. We will accelerate this so that we can work on the wire frame in parallel with the cathodes. Bill asked if it will be acceptable to use parafin to cover some parts of the Rohacell OD that is needed for the ultrasonic cleaning. Lubomir will investigate this.

- Dave is working on the paperwork for making holes in the clean room. We decided to have 4 holes: two in the cathode area and one in each of the small rooms. The holes will be used for nitrogen, compressed air and chamber gas mixture supply.

- We received the solder wire (0.65mm) from UVA that we will use for wire soldering at the beginning. Al has progress with the software (for the Parker controller) used to find the wire position.

Electronics

- Chris: nothing new, waiting for quotation for the rigid-flex tinning.

- Yesterday at the tracking meeting we discussed possible modifications for the fADC125: increase of the gain to cover the whole 12 bit range that was requested by the CDC people. This is not acceptable for the FDC and as seen in the document linked above we are happy with the current version. Eugene insisted that we don't want to have two fADC125 versions which will delay their production and increase the costs, and that this will not solve the problem with the dynamic range. Now they are considering modification of the termination of the CDC pre-amps. In any case for us the fADC125 will not change.

Engineering

- Bill is working on the package assembly jig plate and placed orders for: the new 3M tape gluing tool, cutter modifications, and spacer ring needed for the end window gluing.

- One rigid-flex sample set (two samples) that had higher radiation exposure was taken out of Hall C yesterday. It showed some residual radiation but we still were allowed to have it in 126. The two samples passed the electrical tests successfully. Bill had an idea how to do the mechanical tests: by gluing a Kapton piece on the top of the rigid-flex.

Chamber testing

- The prototype is now in vertical position. To test it, we used 55Fe source triggering with one of the wires. Data was taken, but no results yet due to some software problem; waiting for Beni to fix it.

- At the end we also discussed possible ways to replace the radioactive sources when testing the chambers at Blue Crab. Possible ways: using nitrogen laser (needs special gas mixture), X-ray tube like TV tube. We expect safety issues like with the use of radioactive sources at Blue Crab, so we are giving up unless it's absolutely necessary to have some kind of source there.

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