Minutes of the E895 meeting Graduate Chemistry Rm 403, SUNY Stony Brook Monday 8/14/95 Attending: GR - Gulshan Rai RL - Roy Lacey DC - Daniel Cebra JD - Jim Draper MJ - Marvin Justice MG - Mark Gilkes HL - Heng Liu JW - James Whitfield ZM - Zoran Milosevich JC - Jerry Chance TM - Tatiana Magda EL - Erwan LeBras EC - Eric Colin RS - Rulin Sun HH - Hiro Heijima GR - We have not held a meeting for a while: Last week's meeting was canceled due to the STAR collaboration meeting at BNL. The meeting before that was canceled due to the E910 collaboration meeting. Gulshan Rai described the events of the past weeks. TPC: ==== The detector is now connected to a fully functioning water recirculator. On Friday last, the boom arm was installed. Final planning for the cable routing will be completed this week, for both the fiber optics and the stick power supply cables. The cable trays will be installed in a few days. Electricians will install new power for the stick power supplies. The fiber optics cables are too short to reach the control room, and extensions will have to be purchased. The TPC gas handling system is still at LBNL, being used for STAR tests. Our gas lines are not yet installed, so STAR will continue to use the system for a couple of weeks. A canary chamber presently at Purdue will be used in our gas system at the AGS - the old chamber will remain part of the STAR materials testing setup. GR - The detector will be opened up tomorrow to reinstall the cathode plate. I'd like to put voltage on the field cage. I'd also like to hook up the interlock cables, so that people can see where they connect, though they won't reach the control room (yet). MAGNET: ======= Tom Case, Heng Liu, Paul Chung and Dave Winter have been working very hard on the magnet mapping, which is proceeding very well using the ultrasound technique. Tom has finished the 0.5T field map. The process of mapping the field is slowed by the Hall probe settling time, and as a result the scanning of the rasters is physically demanding. Heng Liu, Paul Chung and Hiro Heijima will complete the 1.0T field map in a few more shifts. The work is being done at night, when the cost of powering the MPS magnet is lower. HL - We are not yet authorized to operate the magnet. We will take care of this soon, as well as obtain green badges. DAQ: ==== Marvin and Ilya Chemakin have succeeded in booting the DAQ and connecting to the LAT servers. The difficulties experienced before are understood, and were related to intermittent edge connections on one of the receiver cards. We now need a VAX to test the trigger program. Thomas Wienold is currently in charge of this task. The trigger program will require modifications, both for E895 and E910. JD - Is a 3200 VAX appropriate for this, vs a 3100 ? DC - The 3200 has Qbus rather than a SCSI port. GR - We may want to hang a disk off it, so the 3100 with SCSI port is better. DC - We'll see if we can spare one. JW - Perhaps CMU can provide one. JW - At CMU we'll be using Peggy McMahan's scaler program. It contains some unfamiliar library calls. GR - The CAMAC libraries were written by LBNL people. JW - We will also be taking responsibility for the TPC pass0 and gain calibrations. Salvo's code is very well documented. MJ - Are these the gains that are loaded into the DSP at run-time ? JW - Yes. We may also be able to help with the trigger program. MJ - The DAQ computers are up and connected to the network, and are registered with the Computing and Communications Department at BNL. It is possible to telnet in from outside, without nameserver problems. However, the IP numbers themselves are still needed to telnet out. The VME processors now have new IP numbers. Ilya and Constantine are already thinking about the code required to integrate the E910 detectors. GR - They will write the code for the beamline wire chambers. LASER: ====== DC - My primary function will be to take care of the laser testing. The paper work needs to be done so that I can take the giant padlock off the power cable. The laser testing should take less than three weeks. In the long term, I'd like to install a computer-controlled laser alignment system. It currently works in a self-triggered mode with a He-Ne beam. With a UV beam such as our laser, it will need an external trigger. This is a prototype development for STAR. GR - Do you have enough help ? DC - Currently it's a paperwork job. If Erwan is interested, he'll help. MUSIC: ====== JC - Jim Draper and I are here to start the setup for MUSIC. I'll be here for four weeks - Jim, one more week. Juan Romero will come later, and stay for four weeks. We're doing inventory now, and thinking about the support structure for MUSIC and how to deal with the rails behind the MPS. SIMULATIONS: ============ Marvin Justice discussed the work needed to be done on simulations. The E895 simulation code is currently maintained on SSEOS (sseos.lbl.gov). A copy of the code is maintained on PHYSGI (physgi01.phy.bnl.gov). The code is not being managed on the BNL machine, partly because of the lack of an Informix license. We could easily move the CVS code repository to NSDSSI (nsdssi.ags.bnl.gov), but this is one of the DAQ computers and may be up and down while people play with the DAQ. We need to install a FORTRAN license on this machine, but there is a site-wide FORTRAN license at BNL, so this shouldn't be a problem. GR - CCD says that they can handle this, if the machine is on the network. MJ - We need to determine: (1) Location of the TPC. (2) B field setting. (3) Drift velocity. MJ - The MPS 1.0T field map has a relatively small flat region, and we will have distortion corrections to deal with even if the TPC is centered in the magnet. GR - What do we give up if we lower the field ? DC - We have field maps at 0.5, 0.75 and 1.0T. The question is, what is the effect on our acceptance ? GR - Which field settings are optimal for which physics program ? Not much statistics is needed for the flow studies. Most is needed for decay/ strangeness physics. MJ - From looking at the field map, 0.5T is more favorable. The flat region is much broader, covering the active area of the TPC. GR - But we don't want to compromise any physics. We could run at both field settings. MJ - Diffusion will be worse at 0.5T, so it may not be the ideal field from that standpoint. MJ - To help standardize the simulations, it would be convenient to fix the beam energies precisely. In the AGS convention, what beam momenta shall we ask for ? I suggest 5.0 AGeV/c rather than 4.84, which is 4.0 AGeV. It's easier for those accustomed to momentum and it's the same kinetic energy, really. Also 2.5 AGeV/c rather than 2.0 AGeV/c. It's an important strangeness threshold. DC - It's important not to leave too big a gap for comparison with the earlier data points. GR - There's a majority interest in the 2.0 AGeV/c run. MJ - Then there is the issue of the drift velocity. Our resolution in the time direction can be improved if we lower the drift velocity. This would involve riding the slope of the P10 velocity curve, rather than the plateau. DC - You want to fill all the available time buckets. GR - You'd have to halve the drift velocity. What does this do to the diffusion ? MJ - STAR plans to servo the drift velocity, since they will not run on the plateau. We could do the same. GR - Will you tell us the optimum settings for a strangeness analysis ? MJ - I can do that. MJ - The measurement of K- is interesting, but the measurement of phi's even more so. I'd be much happier to take the 5.0 AGeV/c point for higher statistics, if the flow people only want enough statistics at the lower energy to extend the excitation function. GR - We also have to consider which targets to run. The canonical system is Au+Au, but there are other possibilities to consider. MJ - There will be severe acceptance problems for asymmetric systems at these energies. We have to look into the simulations. GR - I will be leaving at the end of this week, and then will be at LBNL during September. In my absence, let's continue to hold the weekly meetings at Stony Brook. Prepared by: Mark Gilkes