Difference between revisions of "Minutes-1-20-2011"
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- We discussed two issues with the rigid-flex assemblies. The thickness of the board is 18-18.5 mils, while it is specified to be 14+/-3 mils. Assuming before a thickness of 22 mils, Bill found this will cause a problem in a region where the connectors from two neighboring cathodes overlap. Bill will have the final word if this will still be a problem with 18.5 mils. The second issue is if we want to have the flex contacts tinned. It is related to the soldering procedure we want to use: conventional soldering, or using conductive tape. Fernando explained to us that the tinning can be done later during the board stuffing, although the tin layer will have different shape. This will give us time to investigate both options. Therefore, everybody agreed to approve the rigid-flex production as it is, i.e. with bare gold contacts. We discussed again the two soldering options. We will do more tests in the coming weeks. | - We discussed two issues with the rigid-flex assemblies. The thickness of the board is 18-18.5 mils, while it is specified to be 14+/-3 mils. Assuming before a thickness of 22 mils, Bill found this will cause a problem in a region where the connectors from two neighboring cathodes overlap. Bill will have the final word if this will still be a problem with 18.5 mils. The second issue is if we want to have the flex contacts tinned. It is related to the soldering procedure we want to use: conventional soldering, or using conductive tape. Fernando explained to us that the tinning can be done later during the board stuffing, although the tin layer will have different shape. This will give us time to investigate both options. Therefore, everybody agreed to approve the rigid-flex production as it is, i.e. with bare gold contacts. We discussed again the two soldering options. We will do more tests in the coming weeks. | ||
| − | - Fernando: thanks to Glenn the PR for | + | - Fernando: thanks to Glenn the PR for the ASICs is now out and we expect all the ASICs by the end of May. |
| − | + | ||
| − | + | ||
== Engineering == | == Engineering == | ||
| − | - | + | - Working with the new stringing system is so far successful. Wires for one full chamber were strung. The wire positions were measured by Beni (page 549): the resolution is about 10-15 microns which is acceptable. The main issue is the flatness of the frame on the strongback. Right now it has a conical shape with the outer diameter sticking up (up to 1-2mm at some places) that makes problematic putting the wires on the pads. Bill proposed to add clamps (like a comb) between the wires too press the frame down to the strongback. These clamps may interfere with the wires during the stringing and so far the proposal is to cover the whole frame during the stringing with a flat sheet. It might be a problem to take it out since there's not enough clearance between the wires and the frame when it is at the lowest position. Another option was investigated by Casey: he used the height range |
- 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. | - 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. | ||
Revision as of 18:15, 20 January 2011
January 20, 2011 FDC meeting
Contents
Tentative Agenda
- Production (David)
- Blue Crab status
- ETC schedule
- Electronics (Fernando, Chris, Roger)
- Rigid-flex assemblies
- Foil production status
- Other
- Engineering (Bill, David, Lubomir)
- Wire stringing FDC Log Book, page 549
- Movement control
- Other
- Full-scale prototype studies
- Latest tests FDC Log Book, page 550 (Lubomir)
- Other
Minutes
Participants: Dave, Chris, Simon, Beni, Fernando, Glenn, and Lubomir.
Production
- Dave: there was a walk trough the clean room yesterday with the vendor. The emergency exit door must be sealed better. Glass on the dark room door must be covered. The move in date is postponed to Jan 31. Dave has prepared conduct of operation documents for the clean room.
- New ETC schedule: the full package testing is postponed and squeezed. Fernando: even with the new schedule we may not have the electronics needed for the tests, so we need to have alternative testing procedure.
Electronics
- Chris sent the first article signal cables back to the company to fix the cable problem.
- We discussed two issues with the rigid-flex assemblies. The thickness of the board is 18-18.5 mils, while it is specified to be 14+/-3 mils. Assuming before a thickness of 22 mils, Bill found this will cause a problem in a region where the connectors from two neighboring cathodes overlap. Bill will have the final word if this will still be a problem with 18.5 mils. The second issue is if we want to have the flex contacts tinned. It is related to the soldering procedure we want to use: conventional soldering, or using conductive tape. Fernando explained to us that the tinning can be done later during the board stuffing, although the tin layer will have different shape. This will give us time to investigate both options. Therefore, everybody agreed to approve the rigid-flex production as it is, i.e. with bare gold contacts. We discussed again the two soldering options. We will do more tests in the coming weeks.
- Fernando: thanks to Glenn the PR for the ASICs is now out and we expect all the ASICs by the end of May.
Engineering
- Working with the new stringing system is so far successful. Wires for one full chamber were strung. The wire positions were measured by Beni (page 549): the resolution is about 10-15 microns which is acceptable. The main issue is the flatness of the frame on the strongback. Right now it has a conical shape with the outer diameter sticking up (up to 1-2mm at some places) that makes problematic putting the wires on the pads. Bill proposed to add clamps (like a comb) between the wires too press the frame down to the strongback. These clamps may interfere with the wires during the stringing and so far the proposal is to cover the whole frame during the stringing with a flat sheet. It might be a problem to take it out since there's not enough clearance between the wires and the frame when it is at the lowest position. Another option was investigated by Casey: he used the height range
- 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.
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