Difference between revisions of "Minutes-1-13-2011"

From GlueXWiki
Jump to: navigation, search
 
(8 intermediate revisions by the same user not shown)
Line 8: Line 8:
 
#* PCBs
 
#* PCBs
 
#* Rigid-flex assemblies  
 
#* Rigid-flex assemblies  
#* Foil inspection [http://www.jlab.org/Hall-D/detector/fdc/reports/Cathode_Foil_Inspection_Report_bills.docx report], [http://www.jlab.org/Hall-D/detector/fdc/pictures/Packagingtube1.jpg new packaging]
+
#* Foil inspection [http://www.jlab.org/Hall-D/detector/fdc/reports/Cathode_Foil_Inspection_Report_bills.docx report], [http://www.jlab.org/Hall-D/detector/fdc/pictures/Packagingtube1.jpg new packing]
 
#* Other  
 
#* Other  
 
# Engineering (Bill, David, Lubomir)
 
# Engineering (Bill, David, Lubomir)
#* Wire stringing
+
#* Wire stringing [http://www.jlab.org/Hall-D/detector/fdclog/ FDC Log Book, page 549]
 
#* Movement control  
 
#* Movement control  
 
#* Other
 
#* Other
Line 18: Line 18:
 
# Other
 
# Other
  
<!--
 
  
 
= Minutes =
 
= Minutes =
  
Participants: Bill, Fernando, Mike, Dave, Mark, Chris, Roger, and Lubomir.
+
Participants: Bill, Fernando, Eugene, Dave, Roger, Simon, and Lubomir.
Mike is our new technician.  
+
  
 
== Production ==
 
== Production ==
  
- Dave: the clean room will be ready on Jan. 18, but then Jlab will do the wiring (power and internet) inside, which will bring us to the end of January. Right now Dominion Power is working on the power. In the mean time we will get a temporary staging area.  
+
- According to Tim, Dominion Power will have the power ready by next week. There were weather related delays. Dave: the electrical wiring inside the clean room is done, but data cables remain to be installed. Dave is is also busy with paperwork related to the production: quality plan, conduct of operation, clean room procedure, etc.
 
+
- ETC change request: the package full tests are scheduled to start at the beginning of 2012, but will not have enough electronics for one package until Nov. 2012. At the other hand, the installation is supposed to start  at the beginning of 2013. Lubomir will discuss this with Tim.  
+
  
 
== Electronics ==
 
== Electronics ==
  
- Chris: almost all the PCBs were tested channel by channel and all they are holding 2500V. They were cleaned very well. Fernando: the only operation that is needed is to fill the vias that were not sealed, with humiseal or epoxy. The only concern in doing this (Bill) is the thickness of the humiseal that is need; we need to make sure it doesn't interfere with the wires during stringing.  
+
- Roger: answer from Allflex regarding our foil inspection report. The packing we suggested can be done. The most difficult is to avoid the stains. They will respond to all the questions in our report later this week.
  
- The first 25 rigid-flex boards have arrived. Fernando and Chris found them acceptable from electrical point of view. Bill will check mechanically how do they fit on the cathodes.  
+
- Roger expects e-mails from Fernando and Bill regarding the acceptance of the first article rigid-flex assemblies. Bill checked for matching to the cathode foil and frame, but he will check it also in the drawings. Chris will do some more measurements before the Fernando's approval. After the meeting Roger mentioned (based on Casey's information) that the contacts of the new rigid-flexes are not tinned, but they were tinned on the flexes for the full-scale prototype. We will correct this so that they are tinned in the mass production. Lubomir was concerned of the ground strip on the cathode foil touching the flex: due to the strong coupling it may attenuate the signals; this can be estimated.
  
- Roger showed us pictures from the foil production at the Allflex facility. Bill had suggestions how to improve different procedures.  
+
- Fernando; the first article signal cables had a problem: one of the connectors had opposite polarity. He is contacting the company. Other than that the quality is very good.
  
- We discussed the foil inspection report, linked above. Generally, the first article foils are acceptable but we have several remarks and requirements. Bill will work on the document and we will send it to Allflex a.s.a.p.
+
- fADC125: according to Fernando there are some modifications that have to be done for the next fADC125 version by March 2011. Gerard will be able to work on this starting February.
 
+
- Fernando: first article signal cables are arriving (40 in total) and Chris is going to check them channel by channel.  
+
  
 
== Engineering ==
 
== Engineering ==
  
- Wire stringing: the micrometers have to be installed and we will be ready to start exercising. This is our first priority right now and we will start stringing on Monday. We need help with the software to control the movement system. Tomorrow a Parker representative will come to help us. Dave: if needed we may consider hiring him to write the software.
+
- Wire stringing: this week we started wire stringing (first time at JLab!). After some trials it works well now: we have strung ~50 sense and ~5 field wires. Results for the position measurements on few wires are shown at FDC logbook page 549. For these  measurements we used the laser sensor and the encoder. Results: the sigma of the deviation from the nominal value for the distance between the sense wires, is 6 microns (very good result!), while it is ~25 microns for the sense to filed wire distance. Full scan of the wire positions will be done after all they are installed. Bill: as mentioned before by Eugene we need to define a reference point (detectable by the laser sensor) on the frame to relate it to the wires, it can be put on the strongback. Bill is working also on the attachments for the camera and the magnet.  
  
- The tension on all the wires of a full-scale prototype wire frame (P2) were measured using our new procedure. These tensions were measured also at IUCF few years ago. The results are summarized at page 548 of the FDC logbook: apart from a ~5% systematic deviation, our result reproduces very well the IUCF measurements wire by wire. It means: 1)that our procedure is reliable, and 2) that the chamber tension didn't deteriorate during these years. The systematic deviation can be explained by the additional pins used now to stretch the wire frame on the strongback, or by some differences in the measurement procedures. Lubomir suggested to add adjustemnt of the magnet horizontal position, to make the wire oscillating strictly vertically. The main problem of the procedure is making contact with the wire pads. This can be improved on the HV side (Fernando) by using the HV pads and shorten the 1M resistors.  
+
- The plan is to string all the wires, to solder them and do position and tension measurements (highest priority since we have never done this before). Then we will continue with the gluing of the PCB rings.
On the readout side there were different ideas: clamping directly the wires (Bill) or even using the wires as they are with the weights and lifting one wire at a time with a hook to make contact (Lubomir).  
+
 
 +
- Larry from Cross Computing (representing Parker) was at JLab end of last week working on low level software for the stepper motor controller. We are considering making a contract (for no more than one week work) to finish the job. The software must be open so that we can modify it.
  
 
== Full-scale prototype tests ==
 
== Full-scale prototype tests ==
  
- Lubomir: in general using methane reduces significantly the after pulses. Bill: if we want to use methane it has to be discussed first with the safety people, so that we can have a plan for the gas system well in advance.
+
- Simon presented his results for the FDC resolutions with 40/60 Ar/CO2 gas mixture (page 584). Using Garfield smearing of the drift times in the MC simulations he demonstrates that the effective resolution is close the the one with Gaussian smearing with a sigma of 200 microns. Eugene had questions regarding details of the procedure and the Garfield simulations. Next step: generating smearing with Garfield with the magnetic field on.
 
+
-->
+

Latest revision as of 19:22, 13 January 2011

January 13, 2011 FDC meeting

Tentative Agenda

  1. Production (David)
    • Blue Crab status
  2. Electronics (Fernando, Chris, Roger)
  3. Engineering (Bill, David, Lubomir)
  4. Full-scale prototype studies
  5. Other


Minutes

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

Production

- According to Tim, Dominion Power will have the power ready by next week. There were weather related delays. Dave: the electrical wiring inside the clean room is done, but data cables remain to be installed. Dave is is also busy with paperwork related to the production: quality plan, conduct of operation, clean room procedure, etc.

Electronics

- Roger: answer from Allflex regarding our foil inspection report. The packing we suggested can be done. The most difficult is to avoid the stains. They will respond to all the questions in our report later this week.

- Roger expects e-mails from Fernando and Bill regarding the acceptance of the first article rigid-flex assemblies. Bill checked for matching to the cathode foil and frame, but he will check it also in the drawings. Chris will do some more measurements before the Fernando's approval. After the meeting Roger mentioned (based on Casey's information) that the contacts of the new rigid-flexes are not tinned, but they were tinned on the flexes for the full-scale prototype. We will correct this so that they are tinned in the mass production. Lubomir was concerned of the ground strip on the cathode foil touching the flex: due to the strong coupling it may attenuate the signals; this can be estimated.

- Fernando; the first article signal cables had a problem: one of the connectors had opposite polarity. He is contacting the company. Other than that the quality is very good.

- fADC125: according to Fernando there are some modifications that have to be done for the next fADC125 version by March 2011. Gerard will be able to work on this starting February.

Engineering

- Wire stringing: this week we started wire stringing (first time at JLab!). After some trials it works well now: we have strung ~50 sense and ~5 field wires. Results for the position measurements on few wires are shown at FDC logbook page 549. For these measurements we used the laser sensor and the encoder. Results: the sigma of the deviation from the nominal value for the distance between the sense wires, is 6 microns (very good result!), while it is ~25 microns for the sense to filed wire distance. Full scan of the wire positions will be done after all they are installed. Bill: as mentioned before by Eugene we need to define a reference point (detectable by the laser sensor) on the frame to relate it to the wires, it can be put on the strongback. Bill is working also on the attachments for the camera and the magnet.

- The plan is to string all the wires, to solder them and do position and tension measurements (highest priority since we have never done this before). Then we will continue with the gluing of the PCB rings.

- Larry from Cross Computing (representing Parker) was at JLab end of last week working on low level software for the stepper motor controller. We are considering making a contract (for no more than one week work) to finish the job. The software must be open so that we can modify it.

Full-scale prototype tests

- Simon presented his results for the FDC resolutions with 40/60 Ar/CO2 gas mixture (page 584). Using Garfield smearing of the drift times in the MC simulations he demonstrates that the effective resolution is close the the one with Gaussian smearing with a sigma of 200 microns. Eugene had questions regarding details of the procedure and the Garfield simulations. Next step: generating smearing with Garfield with the magnetic field on.