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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.