Summary of the PEP-N meeting held in Ferrara on March 08, 2001

Present: V. Azzolini, W. Baldini, D. Bettoni, V. Bidoli, R. Calabrese, 
         G. Cibinetto, P. Dalpiaz, M. Negrini, L. Paoluzi, P.Patteri,
         M.Posocco, R. Stroili, A. Zallo

1. Magnet

V.Azzolini shows calculations of magnetic field, produced by TOSCA, with
different geometrical parameters. To optimize the internal space for the
detectors the best configuration showed seems to be the following:

distance between yokes   2.0 m
distance between poles   1.2 m
pole diameter            1.2 m
pole height              0.2 m
current density          2.8 A/mm^2
magnetic field           2.04 Kgauss

Further studies with an increased current density in the coils (the
maximum value for the current should be around 7.1 A/mm^2) will be 
performed in order to obtain field maps with different intensity.
The new simulations will also include the hole corresponding to the
HER beam pipe, to study its effect on the magnetic field.

2. Detector

Considering the provious shape of the magnet V.Bidoli shows a possible
detector
layout with a full-angular-coverage calorimeter. The proposal is to use a
calorimeter like the one of KLOE experiment at LNF, with layers of lead
and scintillating fibers as forward calorimeter and "side" calorimeters.
The energy resolution for this kind of calorimeter is ~5%/sqrt(E); the
estimated time resolution is (50 + 50/sqrt(E))ps.
The "pole" calorimeters need to be thinner (~6cm) so a solution of lead/
scintillator tiles can be adopted; the detection efficiency for such a
calorimeter is around 80% for 20MeV photons and is above 95% for E>40MeV.

For the inner tracking detector a drift chamber has been proposed.
Front end plates thickness: 5cm (equivalent to ~0.1 rad. length)
Side faces: 1mm carbon fiber + 3mm Honeycomb + 1mm carbon fiber.
Gas: 90% Helium + 10% Isobutane
Wires location: square structure 2mm x 2mm as follows: 
                     o  o  o    o = sense wires (TBD) 
                     o  x  o    x = field wires (Alluminium) 
                     o  o  o

The TPC solution will be studied by J.Va'vra

P.Dalpiaz suggests to show at the workshop a single apparatus layout, 
with a single option for each detector component.

3. Comparison with BES

M.Negrini shows a comparison with the apparatus of BES experiment (which 
gives, at present, the most precise measurement of R). The summary is as
below:
                        BES                     PEP-N
                                 Calorimeter:
  sigma(E)/E        21%/sqrt(E)               ~5%/sqrt(E)
  sigma(z)             3.6cm                     9mm
  sigma(phi)          7.9mrad                  ~8mrad
  acceptancy           80%                       ~92%
                                  Tracking:
  B                    0.4T                     0.3T
  sigma(p)/p     1.8%*sqrt(1+p**2)              ~1.5% (estimated)

M.Negrini will simulate the tracking system to obtain a better estimate
for
the momentum resolution.

4. Workshop organization

Rinaldo, in video-conference from SLAC, shows the preliminary program 
of the workshop: more space has been given to the discussion of the
detector.
As a result some theoretical talks may need to be put into a parallel
session.
The preliminary list of speakers who will talk about the PEP-N 
detector and accelerator design is the following:

 J. Seeman (SLAC)     The PEP-N project
 M. Sullivan (SLAC)   Interaction Region
 D. Bettoni(Ferrara)  Detector Layout
 M. Placidi(CERN)     Magnet
 TBA                  Tracking Design
 M. Negrini(Ferrara)  Simulation and Multihadron Detection Efficiencies
 
 J. Seeman (SLAC)     Accelerator Layout
 M. Biagini(LNF)      Lattice Design
 L. Keller(SLAC)      Background
 M. Mandelkern(UCI)   Luminosity Measurement
 A. Onuchin(BINP)     Aerogel and Particle ID
 A. Zallo (LNF)       Electromagnetic Calorimetry
 TBA                  Trigger
 
 P. Bosted (U.Mass)   Baryon Form Factors Measurement at PEP-N
 D. Michael (Caltech) Hadron Calorimeter with MINOS technique
 D. Piccolo (Napoli)  Baryon Detection Efficiencies
 S. Rock (U.Mass)     Nucleon Polarization Measurement

 D. Bettoni (Ferrara) Detector Design Summary 

All the schematics and the description of the apparatus are available on
the
PEP-N web page.



regards, gianluigi.