Difference between revisions of "Minutes-6-3-2010"
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- the PR for the PCBs were submitted, expect to have the first article in August. | - the PR for the PCBs were submitted, expect to have the first article in August. | ||
| − | - Fernando investigate the noise coming from the CAEN HV supply. It radiates rather than transmits through the cables. The strips and wires (mainly the long strips) are picking up that noise. Fernando reduced the noise by re- | + | - Fernando investigate the noise coming from the CAEN HV supply. It radiates rather than transmits through the cables. The strips and wires (mainly the long strips) are picking up that noise. Fernando reduced the noise by re-arranging the ground cable connections. Still two of the cards are showing noise. We discussed if we will have the same problems in the hall, i.e. if the detectors will be picking noise from the same CAEN HV crates that will be used for the FDC and CDC. Fernando explained the HV racks will be far from the detectors, but certainly we have to test this. |
== Cathode redesign == | == Cathode redesign == | ||
| − | + | - Not all of the Bill's modifications are implemented: the keep-out circle at 1057mm is not on the print. Fernando said the cathode foil procurement may take longer (because of the sole source) than for the PCBs; this could be a showstopper for the new design prototype and therefore for the production. | |
| − | + | ||
| − | + | ||
== Full-scale prototype test results == | == Full-scale prototype test results == | ||
| − | - Simon showed results of his simulations using Garfield and Heed packages (FDC logbook page 466). For the present gas mixture of 40/60 Ar/CO2 and present field configuration (2200V on sense and -500V on field wires) he showed several events with 90Sr source and also with cosmic muons. After convoluting the signals with 11ns time constant, the signals look very similar to those we see with a scope or with the fADC. The drift time spectra are also very similar to the ones obtained with the full-scale prototype. The long tails above 160ns are coming probably from tracks close to the field wire, but Simon will look into that. Eugene suggested to create an ntuple in Garfield so that one can easily correlate different parts of the spectra with the different trajectories. | + | - Beni discussed several plots on the FDC log book (page 468), showing the wire coordinates reconstructed from the cathode strips. Resolution is between 0.7 - 1mm. Some of the strips are missing. Certainly in some of the areas the resolution is better. The most likely explanation is the noise. There's also a systematic curving of the wire position; Simon and Beni have seen this effect before and probably it will disappear after calibrating the electronics.Beni also studied the effect of changing the field HV from -500V to -700V with always 2225V on the sense wires (page 477): the maximum drift time gets smaller, but the tail up to 400-500ns is still there. Lubomir explains the tail coming from the tracks close to the field wires: if there are no ion pairs produced close to the line between the wires where the field is strong enough, the electrons will take a long path along the field lines till they rich the sense wire. |
| + | |||
| + | - Simon showed new results of his simulations using Garfield and Heed packages (FDC logbook page 466). | ||
| + | |||
| + | <!-- | ||
| + | |||
| + | For the present gas mixture of 40/60 Ar/CO2 and present field configuration (2200V on sense and -500V on field wires) he showed several events with 90Sr source and also with cosmic muons. After convoluting the signals with 11ns time constant, the signals look very similar to those we see with a scope or with the fADC. The drift time spectra are also very similar to the ones obtained with the full-scale prototype. The long tails above 160ns are coming probably from tracks close to the field wire, but Simon will look into that. Eugene suggested to create an ntuple in Garfield so that one can easily correlate different parts of the spectra with the different trajectories. | ||
- fADC data analyses were discussed above | - fADC data analyses were discussed above | ||
Revision as of 18:03, 3 June 2010
June 3, 2010 FDC meeting
Contents
Tentative Agenda
- Production
- 727 B.C. status
- production planning
- new design one-layer prototype: PCB and cathode PRs, wire stringing fixtures
- Electronics
- fADC125 status (Fernando)
- PCB status (Kim, Fernando)
- CAEN HV noise investigations (Fernando)
- Cathode redesign Bill's changes proposed on the last meeting (Bill, Roger)
- Full-scale prototype test results
- cosmics tests FDC Log Book, page 468 (Beni)
- tests with fADC125: FDC Log Book, page 467 (Lubomir)
- Garfield simulations FDC Log Book, page 466 (Simon)
- Other
Minutes
Participants: Eugene, Bill, Fernando, Glenn, Casey, Mark, Beni, Simon, and Lubomir
Production
- Bill informed us that Ron Bartek promised Tim the specifications for the off-site space to be delivered to Rusty Sprouse no later than Friday. There's no full lease of the property yet. Eugene explained us there's a relation between setting up the Blue Crab off-site space and the Hall B one: same people are involved.
- Bill will take care about creating the production flowchart with Fast Track, based on the above document.
- Brian will bring the fixtures for the wire stringing from UVA on Monday (06/07) and put them in 126. Mark will find space to store the equipment in F117 and as long as there's more free space there, Bill is ready to start setting up the wire stringing. We will use the first articles of the PCBs and cathode foils to produce the new design prototype. We discussed whether we can do the same with the wire and cathode frames: submit PRs for all the frames and use the first ones for the prototype. Bill is confident that the new design will work and we can submit PRs for all the frames; Eugene and Lubomir are also in favor of such decision but we will re-visit this on the next meeting.
Electronics
- Fernando informed us that the DAQ group (Bryan Moffit) is working on the drivers for the fADC125 with LINUX CPU. Beni said he would prefer to use the CPU we have now (VXWorks) because if we can have the LINUX one it will be temporary. Eugene suggested buying a LINUX CPU. Beni explained the three CPUs available now are from different companies, the DAQ people are evaluating them and we better wait before buying such a CPU. Fernando will ask Bryan when we may expect the drivers for the VXWorks CPU. By that time we will use the fADC with the Gerard's program.
- the PR for the PCBs were submitted, expect to have the first article in August.
- Fernando investigate the noise coming from the CAEN HV supply. It radiates rather than transmits through the cables. The strips and wires (mainly the long strips) are picking up that noise. Fernando reduced the noise by re-arranging the ground cable connections. Still two of the cards are showing noise. We discussed if we will have the same problems in the hall, i.e. if the detectors will be picking noise from the same CAEN HV crates that will be used for the FDC and CDC. Fernando explained the HV racks will be far from the detectors, but certainly we have to test this.
Cathode redesign
- Not all of the Bill's modifications are implemented: the keep-out circle at 1057mm is not on the print. Fernando said the cathode foil procurement may take longer (because of the sole source) than for the PCBs; this could be a showstopper for the new design prototype and therefore for the production.
Full-scale prototype test results
- Beni discussed several plots on the FDC log book (page 468), showing the wire coordinates reconstructed from the cathode strips. Resolution is between 0.7 - 1mm. Some of the strips are missing. Certainly in some of the areas the resolution is better. The most likely explanation is the noise. There's also a systematic curving of the wire position; Simon and Beni have seen this effect before and probably it will disappear after calibrating the electronics.Beni also studied the effect of changing the field HV from -500V to -700V with always 2225V on the sense wires (page 477): the maximum drift time gets smaller, but the tail up to 400-500ns is still there. Lubomir explains the tail coming from the tracks close to the field wires: if there are no ion pairs produced close to the line between the wires where the field is strong enough, the electrons will take a long path along the field lines till they rich the sense wire.
- Simon showed new results of his simulations using Garfield and Heed packages (FDC logbook page 466).
