New meeting time starting next week!
One hour earlier, will be Tuesdays 10 Central (one hour earlier than this week)
Gas TPC thoughts:
1A. Gas TPC needs to measure momentum and tag flavor type. Do we need absolute vertex position in the drift distance, if so with what accuracy? We do need to be able to measure the neutrals too, so can't always get t0 from an external tracker since we are interested in interactions that occur inside the TPC and are sometimes fully contained. Baseline electronics design is currently a pipeline/streaming readout option with zero suppression. Sometimes you can get a t0 from a charged track that enters the ECAL, but would like something more agressive for t0. Still working on making the physics case for this.
1B. Do we need FEEs in gas volume? There are some challenges for this. Patrick says that the current plan needs 30 feedthroughs, and there is a current test stand at FNAL (TOAD). Nikolai is aware of some cases where they are in a separate volume, at same pressure. We want about 10 bar to get desired number of events, but might be possible to reoptimize this, especially if we don't reuse ALICE chambers. Nikolai wonders if we can maybe have something more modular with multiple TPCs.
2. T2K mixture: Ar+CF4(3%)+isobutane(2%). But high pressure and CF4 need higher voltages to get gain and MWPC can have stability issues. Diego says can't have isobutane to get scintillation light.
3. Thinks that other structures with maybe more than one gain step (mutliple GEMS or 1GEM+micromegas) might have some advantages. Brookhaven and Stony Brook have lots of experience here. Tanaz and others (Liverpool, Santiago) interested in this. Presentation at CERN by Rui later this week on micropattern detectors.
4. Many items from STAR could be available in 5 years. STAR TPC max radius of 2 m, 2m drift on both sides. But need to motivate everything from the physics case. A lot of the current size is motivated by the requirements on the event rate. Aiming to have ~3% muon momentum resolution. For FD it is 4%, and we'd like to match or do a bit better.
Nikolai has an IROC GEM setup in lab. New magnet design in Saclay. He can send us more details on these items.
GOAT(Tanaz): Need to open the pressure vessel again and debug. Currently can't get above 2150 V. At 7 bar we got up to ~2900 V with a gain of ~1000. But now get breakdown above 2150 V. So currently moving on to GEM tests.
TOAD(Naseem): Moved to test beam facility just before Christmas and have passed vacuum operation readiness review. Hope to pull vacuum again soon. Still need ORC for high voltage and high pressure. Have some test electronics cards from US supplier and UK soon. Hope to be able to make a decision about full order soon.
Please contact Patrick and Alysia to get on the agenda for the collaboration meeting.
Talk to everyone one hour earlier next week.