Project NICA'

1
Project NICA. Concept of collider detector (I)
2
Requirements

• Fit into accelerator geometry.
• Angular acceptance ? 4 ?.
• Frequency of events detection 104 Hz.
• Events mean multiplicity 600.
• Momentum resolution of charged particles lt
  1.
• Detection of ?.
• Detection of short-lived (charm) particles is not
  required.

3
Concept of detector

• Beams intercept point.
• Silicon vertex detector.
• 3. Toroidal magnet with drift tubes trekker.
• 4. Toroidal magnet coil (8 coils).
• 5. Multiplicity detector, electromagnetic and
  hadron calorimeters, TOF system (RPC).
• 6. Accelerator quad.
• 7. Multiplicity detector and TOF system (RPC).

8. Electromagnetic and hadron calorimeters. 9.
Muons detector. 10. Accelerator chamber.
11. Collider beam. The setup is
symmetric respect the plane A-A. The right part
of the setup is not shown. Setup overall
dimensions are along the beam 7 m, diameter
4.5 m.
4
Setup main parameters
5
Distinctive feature of particles detection and
identification.
1. Silicon vertex detector pitch is chosen to
be 0.2 0.5 mm which is 10 times higher then
technologically possible now. This choice
provides 10 times chipper device. Coordinate
accuracy ?0.1 mm of single measurement is quite
sufficient for hyperons detection and
reconstruction of events with multiplicity ?
600. 2. Rotation of particle with momentum 2
GeV/c in magnetic spectrometer is ? 60 mrad. It
is to be compared with angle of multiple
scattering in drift tubes tracker 0.4 mrad.
Momentum resolution is estimated to be 0.6. 3.
High demand is shown to accuracy of TOF
measurement. Difference of TOF of electron and
pion with momentum ? 0.5 GeV/c (decay of ? and ?
mesons) on basis of 1.5 m is 400 ps. TOF system
must have resolution 50 80 ps. (RPC).
6
Distinctive feature of particles detection and
identification.

• 4. Electromagnetic calorimeter with shower
  maximum detection may drastically improve
  capability of electron hadron separation.

7
One more remark on the physical
program. Emphases on high multiplicity trigger.
8
The paramount important parameters of present
research are energy density and temperature of
hadronic matter. These values are determined by
primary energy of nuclei and its impact
parameter. An another independent way to control
thermodynamic state of system is to select events
with predetermined multiplicity of secondary
products. Technical way to achieve this goal is
implement effective high multiplicity trigger
sensitive both to charged and neutral secondary.
The domain of very high multiplicity z gt 4,
zn/ltngt was not yet studied (VHM) nether in NN
nor in AA collisions. The higher is multiplicity
the higher is energy dissipation, higher is
achievable density and deeper is thermalization
process. Near the threshold of reaction all
particles get small relative momentum. The
kinetic energy approaches to potential one what
is necessary condition for onset of phase
transitions. In thermalized cold and dense
hadronic gas as consequence of multiboson
interference a number of collective effects may
show up.
9
Comparison of longitudinal and transverse
momenta behavior in c.m.s.
Manifestation of transverse flow ?
p
z
p
0.2
x
pp 70 GeV
Complete thermalization?
0
20 30 40 50 60
70
Manifestation of longitudinal flow ?
10
Multiplicity distribution in PbPb interactions
at Elab 160 A Gevas measured by WA98 setup at
CERN
104
101
11
One can extrapolate data to 6 order of magnitude
down and presumably reach multiplicity ? 840. One
can speculate to reach a new mechanism of
hadronization and a new fashion of phase
transitions. Since we are plane to collect 5?109
central events per year we may get 5?103 very
exotic and possibly unusual events.
12
Lessons we lerned performing "Thermalization" pr
oject at U-70
Cost and manpower estimate.
13
Lay-out of the SVD setup at U - 70.

• Scheme of the SVD installation at U - 70.
• ?1, ?2 -beam scintillation and Si-hodoscope
• ?3, ?4 - target station and vertex Si-detector
• 1, 2, 3-the drift tubes track system
• 4 - magnetic spectrometer proportional chambers
• 5- threshold Cherenkov counter
• 6 - scintillation hodoscope
• 7 - electromagnetic calorimeter.

14
SVD hall
U-70 proton beam
15
Setup schematic view.
Cherenkov counter, 36 ch.
Micro strip VD, 10 000 channels.
Drift tubes tracker, 2400 channels
Magnetic spectrometer, 10 000 ch.
EMC, 1500 cells.
16
Silicon micro strip vertex detector. An exsample
of foil targets imaging.
4 mm
17
Silicon micro strip vertex detector. An exsample
of pC interaction event.
28 charged tracks
18
Silicon vertex detector
40 cm
19
Module of drift tubes tracker.
1 m
20
Assembly od drift tubes tracker.
21
Charm particle D0 detection
pC D0 X, 70 GeV.
22
Search for pentaquark ?, 2005.K_0 found in
magnetic spectrometer.
Total statistics Signal392, Backg1990. Signific
ance8s.
1.500 1.600
23
Cost and manpower of two components of SVD setup
at U-70.

• Silicon vertex detector. 10 000 channels.
  Designed and implemented 1999 2002, Selenograd
  and MSU. Cost 250 th. . Manpower 4 persons.
  Cost per channel 25 .
• Drift tubes tracker. 2400 channels. Designed and
  implemented 2003 2005, PPL JINR. Cost 55 th.
  . Manpower 4 persons with 30 occupancy. Cost
  per channel 22 .

24
Cost estimate.
As estimated from SVD (U-70)
25
Some experts remarks.

• Peter Senger. 1. Do not build TRD --
  Agree. 2. Do not build Silicon vertex
  detector. Interesting idea to think
  about. 3. Do not build calorimeters --
  Agree do not build hadron calorimeters.
  But EM calorimeters are very important. 4.
  Detailed feasibility studies have not been made
  and will take years. -- Disagree.
  5. The time for realization is strongly
  underestimated. -- Disagree.
• N.Xu. 1. A pair of ZDC are needed. --
  Not sure. Need to think. 2. Take a staged
  approach of detector construction. --
  Agree. Good idea.

26
Conclusion
27
We are optimistic and looking forward to see NICA
operation.