From GARVEY@lampf.lanl.gov Wed May 18 17:56 MDT 1994 Received: from p2vax.lanl.gov by p2hp3.lanl.gov with SMTP (1.37.109.4/16.2) id AA21281; Wed, 18 May 94 17:56:03 -0600 Return-Path: Date: Wed, 18 May 1994 17:53:27 -0600 (MDT) From: GARVEY@lampf.lanl.gov To: isenhowe@acuvax.acu.edu, sadler@acuvax.acu.edu, chenyc@phys.sinica.edu.tw, pkteng@ccvax.sinica.edu.tw, kiang@phys.sinica.edu.tw, ming@fnal.fnal.gov, geesaman@anlphy.phy.anl.gov, b04353@anlvm.ctd.anl.gov, kaufman@anlphy.phy.anl.gov, pvs@fnal.fnal.gov, zeidman@anlphy.phy.anl.gov, brad@erin.caltech.edu, bmck@erin.caltech.edu, chuckb@fnal.fnal.gov, cooper@fnal.fnal.gov, mishra@fnal.fnal.gov, garvey@lampf.lanl.gov, john@lampf.lanl.gov, morris@lampf.lanl.gov, moss@p2vax.lanl.gov, tcarey@lanl.gov, jansen@p2vax.lanl.gov, leitch@p2vax.lanl.gov, lillberg@p2vax.lanl.gov, plm@p2vax.lanl.gov, peng@p2vax.lanl.gov, kirk@rouge.phys.lsu.edu, haas@nmsnp1.nmsu.edu, tchang@nmsnp1.nmsu.edu, mwang@nmsnp1.nmsu.edu, kyle@nmsnp1.nmsu.edu, burleson@nmsnp1.nmsu.edu, park@lampf.lanl.gov, kaplan@fnal.fnal.gov, awes@orph14.phy.ornl.gov, kim@orph14.phy.ornl.gov, obenshain@orph14.phy.ornl.gov, saini@orph14.phy.ornl.gov, young@orph14.phy.ornl.gov, stankus@orph01.phy.ornl.gov, cggroup@comp.tamu.edu, tribble@comp.tamu.edu, eah2490@zeus.tamu.edu, dkoetke@exodus.valpo.edu Message-Id: <940518175327.21206b84@lampf.lanl.gov> Subject: MInutes Of April Collaboration Meeting Status: RO Dear Colleauges, Below are the minutes of our April Collaboration Meeting at FNAL. It was an enjoyable meeting! I would like to thank Chuck for making the local arrangements and the rest of the attendees for their contributions to a successful meeting. Best Regards, Gerry Minutes of the 4'th Collaboration Meeting of E866 Attendees: Brown, Carey, Cooper, Gagliardi, Garvey, Geesaman, Hawker, Ho, Isenhower, Kaplan, Kaufman, Kirk, Koekte, Kyle, Lee, Leitch, McCelland, McGaughey, Morris, Moss, Papavassliou, Peng, Zeidman The 4th Collaboration Meeting of E866 was held at Fermi Lab on April 8-9, 1994. The actual agenda and statement of purpose of the meeting are attached as Appendices 1 and 2, respectively. Chuck Brown has agreed to send out one copy to each institution of the transparencies presented at the meeting. STATUS of E866 In his report on the status of E866, Garvey pointed out that the collaboration was still expanding with the addition of Argonne National Laboratory and Louisiana State University to the list of collaborating institutions, as well as increasing participation at institutions already signed up. The original E866 physics goals of a precision measurement of dbar/ubar in the proton remains the principle focus. There is continuing high physics interest in the subject of of the experiment as reflected in recent theoretical papers dealing with the subjectin PRL and PR D, as well as exciting result from NA51 at CERN, which has been submitted for publication to Physics Lett.They find ubar(x)/dbar(x) in the proton =0.56+-0.04+-0.05 at x=0.18 or delta(x)=dbar(x)-ubar(x)/dbar(x)+ubar(x)=0.28+-0.035 This large asymmetry is larger than expected for any of the credible parameter- izations of dbar/ubar that fit the NmC measured violation of the Gottfried Sum Rule. The NA51 result,if true, indicates that there is very exciting physics to be learned from the E866 measurement of dbar/ubar as a function of x. Garvey also mentioned that a new schedule for fixed target running was "under consideration" by FNAL management. It would have E866 taking Tevetron beam in early January 1996, rather than early July 1995. This change in schedule impacts what needs to get done this summer at FNAL. Garvey closed his status report with a list of the major tasks on the experiment, listing the people and institutions currently responsible. BRIEF TASK SUMMARIES Detectors The meeting then proceeded with a series of of brief presentations on the tasks associated with the experiment. Chuck Brown gave an overview of the present situation with the wire chambers pointing out that the positions of the adsorb- er and the Station 1 chambers have not been optimized. Moving them upstream allows the position resolution at the target to be improved to some 50 cm with little or no sacrifice in mass resolution.Pat McGaughey's calculations seem to support this view. Don Isenhower reported that the scintillator hodoscope task was under good control. It has not yet been determined who will build the additional scintil- lators to backup the proposed enlargement of the Station 1 WCs.This part of the job will involve ACU working with either FNAL or LANL. The thickness proposed for these new scintillators is 3 mm. Garvey reported that in a recent conversation with Glenn Young he said they were still very interested in E866 ant that ORNL agrees to get the proportional tubes up and running this summer. Level 2 Trigger Carl Gagliardi reported that they now have a LeCroy 2366 on hand. Carl believes it will take two months to evaluate if the 2366 is fast enough to do be an adequete 2nd level trigger. There was an extended discussion of whether this planned trigger upgrade allowed sufficient flexibility to accumulate the data necessary for an accurate determination of the trigger efficiency. At Don Geesaman's suggestion a Level 2 Trigger Subgroup was formed to discuss this matter and report back to the collaboration. The subgroup consists of Carl Gagliardi (leader), Vassili Papavassiliou, Dan Kaplan, Pat McGaughey, and J. C. Peng. We await their report. Magnetic Field Configuration J. C. Peng reported on the magnetic field configuration in the spectrometer. As he reported at the third collaboration meeting, it is clearly advantageous to reinstall SMo. This provides some increase in acceptance, but allows much greater flexibility in setting SM12 and SM3. This flexibility may be crucial in finding field settings that satisfy both our physics requirements and radiation safety requirements. It is unlikely that we will be able to predict the best settings from the radiation safety perspective until we start running. Targets Garvey reported that the FNAL system will hold the density of our LH6 target stable at .06%. As we have located very high purity D2 (99.97%) the only issues remaining have to do with the ortho/para mixtures that are present in the liquid/vapor. Relative LH2/LD2 density should end up being known to .1P.2%. Data Acqusition and Analysis Tom Carey said he had little new to report. He and Mike Leitch have agreed that the data could be recorded on EXB8505 tape drives. They can handle 500 KB/S with a capacity of 5 GB. cartridge. E866 will need two of these drives. Tom noted that FNAL is adopting these drives as their standard. Tom estimated that the cost of new and replacement equipment for the DAQ system will come to $28 K. This does not include the new tape drives or the hardware and software needed for a new Level 3 trigger to be discussed below. As we had become pressed for time, Mike Leitch made a somewhat abbreviated presentation on data monitoring and data analysis issues. There are two large jobs that should have people assigned to them. A database system needs to be set up for the experiment. Mike presented a list of the some of the quantities that need to be recorded, but someone needs to take on this task which could become one of the most important parts of the experiment(LANL-NMSU,LANL-ORNL,?). The other task is writing the software supporting the hoist server. The person for this task is as yet unidentified. Mike reminded the collaboration that our goal of analyzing 10-20% of the data on line will require a dedicated group (3-4 people) in addition to the team required to run the experiment. Results from E655 Don Geesaman reported briefly on the E655 results for the ratio of the deep inelastic scattering cross section from the neutron to that from the proton. at small x. Their is very good agreement in the region of x where E655 and PNMC overlap. At x<.001 the E655 data for sigma-n/sigma-p hover around 0.95 rather than 1 as would be expected from a simple parton picture. As the neutron cross section must be inferred by using a deuterium target, there is a possibility that shadowing could play a role. Again, E866 measurement will be able to shed light on this interesting problem. Magnetic Field Calculations Walt Sondheim showed some very interesting results with beautiful displays of magnetic field calculations he has been doing using the 2-D program and the 3-D program, Tosca. Walt has an excellent model of SM12 and is proceed- ing to do calculations in regions where the fields are relatively complicated. At present, the 2-D calculations reproduce the measured field in SM12 to 1% in regions where the magnet gap is uniform. There are still some obvious bugs in the 3-D calculation, but it appears that Tosca will be an great aid to our knowledge of the magnetic fields in the spectrometer. Walt plans to calculate the effect of energizing SMO on the SM12 field in the upstream end once he gets the bugs out of the program. A New Level 3 Trigger Proposal Tom Carey and Pat McGaughey presented some new ideas on how to replace the present customized Level 3 trigger. The present Level 3 trigger is a hard-wired computer that takes wire chamber data and constructs a trajectory that allows the separation of target and beam dump events and make a cut on a rough value. of the mass. This present trigger is very fast ~10 micros/event, but is probab- ly very difficult to make operable. Tom and Pat suggest using a VME multipro- cessor board based on the TMS 320C40 chip. While this system would produce a Level 3 trigger that is much slower than the present one, it appears that the system can be made commensurate with the average 100micros dead time to read out an event. Pat felt a Level 3 trigger system could be put together that would allow us to select high mass beam dump events as well as all of the target events. Tom and Pat presented several options, one of which involved removing the Level 3 Trigger from the event trigger and put it instead on the VME Buss and employ it as a post-readout event tagger. It would have plenty of time to work in this configuration and could sort events between target and beam dump, greatly simplifying the task of "on-line bicycle analysis." The issue of where to go with the level 3 trigger is now under very active consideration by Pat and Tom, as well as J. C. Peng and L. D. Chen, who is from Academia Sinica. We were fortunate that S.C.Lee of the Academia Sinica was able to be present at our meeting as he happened to be at FNAL on other business. He explained that there are a group of 17 physicists and 2 technicians in the high energy group at the A.S.. They receive an equipment budget on the order of 0.5M$/year Their major effort is on CDF, but in their new three-year proposal they have shown a commitment to E866 as well. This summer, Professor Lee indicated that they will send a Postdoc and a Tech to LANL to work on E866. They are also able to contribute to the hardware costs associated with the third level trigger. Recabling of E866 Shekar Mishra gave us an up-to-date report on the status of the detector cabling. As many of you know, many of the cables were disconnected in prepara- tion for the Tiger Team's visit to Fermi Lab. According to Shekar, many of the cable labels are lost, so the cabling job will be extensive . Shekar also claimed that the discriminator crates are in bad shape and he suggests that we replace them. He estimates the cost of this job to be $12 K, plus labor. Care will have to be taken to see that each preamp disc card is properly fused. While Shekar's recommendations may represent the best course of action, it requires furthur looking into before committing to fixing all the discriminator crates. PROPOSAL FOR NEW STATION 1 WIRE CHAMBERS Chris Morris presented his proposal to replace the present 30x48" wire chambers at Station 1 with 40x48" chambers. Calculations presented earlier indicated that for certain spectrometer settings this increase would increase our acceptance by a factor of two. Chris presented evidence that his prototype chamber could handle 180,000 events/s in2 , which is more than three times the rate that was the case for E772 54,000ev/s in2. As he is proposing to keep the same number of wires as the existing chambers, the wire spacing is being increased. To keep the charge collection time in the chamber from increasing, he proposes to use a faster gas CF4-C4H10 or CF4-CO2. These gases are more expensive - approximately $1 K per bottle,which lasts about two weeks. There was vigorous discussion abut the environmental conditions that these chambers would have to deal with in Meson East. Chris took note of many of these and will subject his chamber to extremes of temperature and humidity. LANL proposes to construct and test an actual chamber in the LAMPF test beam this September. Chris will report back at the next collaboration meeting on the performance of the chamber and the results of the test run. If the tests are satisfactory, the set of three wire chambers will be built and installed before the summer of 1995. The collaboration unanimously approved that Chris proceed with his tests as proposed. Valparaiso University Don Koetke made a presentation to the group on what Valpariso could provide to E866. The Valparasio group consists of two people (D. K. and Shival Stanislaus), plus 1/2 technician. They have worked on the MEGA experiment at LAMPF. Don said that they have had extensive experience in software for second and third level triggers. The E866 collaborators are to decide on the addition of the Valparaiso group to the collaboration. E866 Trailer Chuck Brown reported that he was being asked to sign off on E866 receiving a new counting house to be fabricated using two existing trailers. This solution is $50K cheaper than a new "CDF style" trailer and will provide us with 750 sq. ft. It may be ready for some form of occupancy this summer. There was discussion that we needed to pay attention to potential interference between the location of the entryways and the space that will become the E866 shift monitoring room. The discussion of potential new physics were cursory. If we are planning to do any additional physics that would extend beyond the first period of fixed target operation, we will have to go to the PAC for approval. Any serious ideas to be presented to the PAC this Fall should be presented at the next collaboration meeting. Garvey promised to send out a white paper on pi+- on deuterium Drell-Yan measurements of isospin violations in the valance quark sector. SUMMER 94 WORK AT FNAL The rest of the meeting was spent in working out the details of the work to be carried out at Fermi Lab. The likely change in the fixed target schedule to January 1996 reduces the pressure on what needs to be accomplished this summer, as the summer of 1995 will now be available for installation and tune-up. However,given the fact that a rather sizable work force is available this summer,it was felt important to get much of the groundwork of detector repair, construction, installation, and recabling done this summer. In sofar as it facilitates detector checkout, we will try to bring the PDP-11 and the Mega- memory into operation. The Megamemory will be turned on early in the summer if it works,fine.If not, we will not work on repairing it. Dan Kaplan and Tom Carey will be looking into these matters. Ideally,it would be nice to have some DAQ up and running by July, as a part of the detector tasks(Hodoscopes) will be completed by then. If the essential elements of the old DAQ system do not redily come on-line, a simple stand-alone acqusition system will be provided for wire chamber checkout. The following is a tentative list of tasks, personnel, and dates people expect to be at FNAL. Scintillator Hodoscopes: Leader, Don Isenhower Week Supervisor Team May 16 Don Isenhower Josh Willis May 23 Don Isenhower Josh Willis, Josh Bush May 30 Don Isenhower Josh Willis, Josh Bush June 6 Don Isenhower Josh Willis, Josh Bush, Derek Wise, Rusty Taub June 13 Rusty Taub Josh Willis, Josh Bush, Derek Wise June 20 Rusty Taub Josh Willis, Josh Bush, Derek Wise Task Expected to be Complete ----------------------------------------------------------------- Proportional tubes: Leader, Glenn Young Week Supervisor Team Early May Chuck Brown - settle safety requirements for gas handling July 18 Glenn Young Paul Stancus, Terry Aves July 25 Glenn Young Paul Stancus, Terry Awes Till Complete ----------------------------------------------------------------------- Wire Chambers: Stations 2 and 3 and recable Station 1 Leader, Shekhar Mishra Week Supervisor Team June 20 Shekhar Mishra* Josh Willis, Josh Bush, Derek Wise,FNAL Tech July 4 Shekhar Mishra* " " " " " " " " July 11 Shekhar Mishra* " " " " " " " " July 18 " " " " " " " " " " July 25 " " " " " " " " " " Aug. 1 " " " " " " " " " " *Still under negotiation ------------------------------------------------------------------------- DAQ Leader, Tom Carey Week Supervisor Team May 30 Carey-Kaplan Ting, ? June 6 " " " " June 23 June 20 June 27 --------------------------------------------------------------------- We must not forget to remove the" RF hut" and the hardware associated with the Silicon Tracker.Chuck thinks this job should be treated as a filler to be done when there is slack time in the tasks listed above. The Meeting adjourned at 2:15 with the understanding that the next meeting will be held in October to evaluate the accomphishments of the summer and discuss new physics ideas in an indepth fashion.