Difference between revisions of "Minutes-7-1-2010"
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== Production == | == Production == | ||
− | - Bill: the PR for the clean room is awaiting Teresa Danforth's signature (it's a vacation time). Bill placed a PR (that is signed already) for two granite tables with wheels to be delivered directly in 727 B.C. We will need in total 11 | + | - Bill: the PR for the clean room is awaiting Teresa Danforth's signature (it's a vacation time). Bill placed a PR (that is signed already) for two granite tables with wheels to be delivered directly in 727 B.C. We will need also in total 11 formica tables for the production. Bill looked already to find some surplus tables. We could take one or two from 126. Before purchasing the rest ($500 each) we will look around to find some. On some of the tables we must be able to put 700-800lb. |
- Bill placed a PR for the g10 wire frames (30 pieces); the goal is to have them by middle of September. The template for the rochacell rings will be ready next week. The plan is to have two students (working now with Mark) working on the rochacell. Mark asked where to store the rings. Bill prefers to store them on a flat surface, maybe table. We will look to find some space for storage. Lubomir: today we got 6 more feet in EEL 126 from Hall C. After coordinating with Dave Mack, we rearranged their tables. We will use the extra space also for a new rack for the new gas equipment. | - Bill placed a PR for the g10 wire frames (30 pieces); the goal is to have them by middle of September. The template for the rochacell rings will be ready next week. The plan is to have two students (working now with Mark) working on the rochacell. Mark asked where to store the rings. Bill prefers to store them on a flat surface, maybe table. We will look to find some space for storage. Lubomir: today we got 6 more feet in EEL 126 from Hall C. After coordinating with Dave Mack, we rearranged their tables. We will use the extra space also for a new rack for the new gas equipment. | ||
− | - Bill started working on the wire stringing fixtures. We agree that this work has highest priority right now. Bill discussed the way the wires will be pushed down locally, close to the soldering pads. His idea is to use a diffraction plate with grooves | + | - Bill started working on the wire stringing fixtures. We agree that this work has highest priority right now. Bill discussed the way the wires will be pushed down locally, close to the soldering pads. His idea is to use a diffraction plate with grooves: 50 grooves/mm with about 10 microns depth. The grooves will keep the wires at the same spacing while pushing them down. |
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== Cathode redesign == | == Cathode redesign == | ||
− | - Roger | + | - Roger prepared the drawings according to the modifications from the last week: increased O.D. with flaps to improve the grounding. Except for few minor modifications (extra flaps in the areas without cards) the design is ready to go, hopefully next week. Roger will send the design to the vendor. We discussed what our requirements will be. Bill suggested to ask for prices: 1) for 60 cathode foils and also 2) if we use the whole material for about 120 foils. We will have 4 foils in the first article and then 4-6 weeks time to check them and start the rest. We discussed how to transport and store the foils. Bill suggested to have them stored in rolls. Mark had suggestions about the material to separate the foils in the rolls. |
== Full-scale prototype test results == | == Full-scale prototype test results == | ||
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+ | - Lubomir showed a plot: the mean signal vs drift time | ||
- Lubomir is analyzing the FADC data from the last week. Ther results are posted at the FDC logbook, pages 494-500. Shown are the areas that were covered by the test, by overlapping the three cards (for the wires, top strips, and bottom strips) at different positions. While the resolutions from the strips are OK, there are several problems with the results. The wire position as reconstructed from the ratio of the total top to bottom charge is shown at page 499. The wires are closer to the top at the middle of the chamber and closer to the middle between to two cathodes, at the shortest wire side. The wire position variations are up to 1mm. There are no visible variations along the wires within the +/-12cm covered by these tests. People asked if we can turn the chamber other way around to see if there are any gravitational effects. Lubomir: the chamber will not work after such a procedure because of the dust inside; can try this only at the end of the tests. Other possibilities, like frame deformation during the wire winding, were also discussed. The easiest test to be done is probably to scan the wires over their entire length, but requires many different positions of the cathode cards. At page 500, shown is the mean maximum signal from the wires, as a function of the position on the chamber. There's some inhomogeneity in the distribution, representing the gas gain, that has to be further studied. The speculation is that it is caused by the gas leakage. Bill asked if we can study this with an oxygen sensor. Beni: we got one but we need a pump at the output of the chamber because of the high impedance of that device. | - Lubomir is analyzing the FADC data from the last week. Ther results are posted at the FDC logbook, pages 494-500. Shown are the areas that were covered by the test, by overlapping the three cards (for the wires, top strips, and bottom strips) at different positions. While the resolutions from the strips are OK, there are several problems with the results. The wire position as reconstructed from the ratio of the total top to bottom charge is shown at page 499. The wires are closer to the top at the middle of the chamber and closer to the middle between to two cathodes, at the shortest wire side. The wire position variations are up to 1mm. There are no visible variations along the wires within the +/-12cm covered by these tests. People asked if we can turn the chamber other way around to see if there are any gravitational effects. Lubomir: the chamber will not work after such a procedure because of the dust inside; can try this only at the end of the tests. Other possibilities, like frame deformation during the wire winding, were also discussed. The easiest test to be done is probably to scan the wires over their entire length, but requires many different positions of the cathode cards. At page 500, shown is the mean maximum signal from the wires, as a function of the position on the chamber. There's some inhomogeneity in the distribution, representing the gas gain, that has to be further studied. The speculation is that it is caused by the gas leakage. Bill asked if we can study this with an oxygen sensor. Beni: we got one but we need a pump at the output of the chamber because of the high impedance of that device. |
Revision as of 18:00, 1 July 2010
July 1, 2010 FDC meeting
Tentative Agenda
- Production
- 727 B.C. status
- wire frame production plans
- plans for wire stringing in 126
- Cathode redesign: finalizing (Roger, Bill)
- Full-scale prototype tests
- tests with fADC evidence for O2 contamination, FDC Log Book, page 503 (Lubomir)
- oxygen contamination measurements Beni's scheme
- cosmic tests (Lubomir for Beni) FDC Log Book, pages 501 - 502
- Other