Mixed Phase Detector (MPD)

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Mixed Phase Detector (MPD)
MPD
Joint Institute for Nuclear Research Conceptual
project
S.Afanasiev, V.Babkin, A.Baldin, S.Bazylev,
V.Borisov, D.Driablov, V.Golovatyuk, A.Isupov,
V.Krasnov, V.Ladygin, A.Litvinenko, Ju.Lukstinsh,
A.Malakhov, E.Matyushevskiy, I.Migulina,
N.Piskunov, E.Plekhanov, A.Shabunov, S.Shimansky,
I.Slepnev, V.Slepnev, I.Tyapkin, S.Vokal,
Yu.Zanevsky, P.Zarubin, L.Zolin.
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Experimental setup should allow to measure -
Event-by-event fluctuations. The hadron yields
and momenta should be analyzed event-wise in
order to search for strong fluctuations which are
predicted to occur in the vicinity of the
critical endpoint and when penetrating the
coexistence phase (the mixed quark-hadron phase)
of the first order deconfinement phase
transition. In order to subtract the (dominant)
contributions from resonance decays one should
measure the yields of the relevant short-lived
hadron resonances. - Multistrange hyperons. The
yields, spectra and collective flow of (multi)
strange hyperons are expected to provide
information on the early and dense phase of the
collision as they are produced close to
threshold. Therefore, these particles are
promising probes of the nuclear matter equation
of state at high baryon density. - HBT
correlations. Observation of short correlations
of p, K, p, ? hadrons allows one to estimate the
space-time size of a system formed in
nucleus-nucleus interactions. Alongside with the
increase of fluctuations, the spatial size of the
system is expected to be enhanced at the phase
transition getting smaller near the deconfinement
point due to softening the equation of state (the
"softest point" effect). - Penetrating probes.
Measurements of dilepton pairs permit to
investigate the in-medium spectral functions of
low-mass vector mesons which are expected to be
noticeably modified due to effects of chiral
symmetry restoration in dense and hot matter.
Specific properties of the s-meson as a chiral
partner of pions, which characterizes a degree of
chiral symmetry violation, may be in principle
detected near the phase boundary via a particular
channel of s-decay into dileptons or correlated
??-pairs. Above a beam energy of about 15 AGeV
also charmonium might be detectable. J/? mesons
are a promising probe for the deconfinement phase
transition. - Open charm. D-mesons probe the
early phase of the collision and are sensitive to
in-medium effects due to chiral symmetry
restoration.
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MPD
Setup overview
Scheme of the MPD setup. TPC - Time Projection
Chamber SVS - Silicon Vertex tracking System
TRD - Transition Radiation Detectors TOF - Time
of Flight detectors EC - Electromagnetic
Calorimeters LENS - magnetic focusing lens of
collider
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Main components of proposed MPD setup -
Superconductive Magnet System (MAGNET COILS) -
Vertex tracking System - Central Arm - Two
Forward arms Each Arm include Time Projection
Chamber (TPC) Transition Radiation Detectors
(TRD) Time of Flight detectors (TOF)
Electromagnetic Calorimeters (EC).
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6.2 Superconductive Magnet System The
superconductive magnet system is composed by two
pairs of concentric coils and provides a field
(1-2T) parallel to the beam. For the forward
angle, the magnetic field is formed by iron cones
and produces a radial magnetic field for the
forward angle analysis. The primary
physics-driven requirements for the central
magnet design are (i) No mass in the
apertures of the spectrometer arms to minimize
interactions and multiple scattering of particles
produced in the primary collision and to minimize
albedo from the magnet poles. (ii) Dense
material near the collision point in the
apertures of the forward arms to serve as hadron
absorbers. (iii) Reasonably uniform field
that could be mapped to a precision in the field
integral of about 2 parts in 1000. (iv)
Control over the radial field distribution to
allow creation of a "zero field" region near R
0. (v) Minimal field integral for the region
R gt 200 cm, the radius of the TPC. Field in the
region of the photomultiplier tubes of the TOF
and the Electromagnetic Calorimeter are also
required to be low. (vi) The magnet must be
easily moveable to allow access to detector
components for commissioning, maintenance and
replacement.
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Silicon Vertex tracking System(SVS)
MPD
The vertex tracking is based on highly segmented
silicon pixel and microstrip detectors at
mid-rapidity, and further silicon pixel detectors
in the forward direction. Three internal central
layers of SVS are constructed from silicon pixel
detectors and three outer layers are built from
microstrip silicon detectors with a pitch from 25
to 50 mkm. They will be arranged in two
half-shells and will cover approximately
-5olt?lt40o and almost 2? in azimuth. Pixel sensor
technology is essential for the resolution of the
high track density in heavy ion collision in the
internal layer. Microstrip detectors also could
be used in the more outward layers where the
occupancies are less severe. The forward silicon
detectors will consist of four pixel cones per
side that match the geometrical acceptance
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Tracking System
A large Time Projection Chamber (TPC) is
proposed as a main tracking device for the
detector at future collider. The ambitious
physics program poses unprecedented requirements
on the precision of the TPC. This modern
experiments plan to use TPC at high charged
particles multiplicities of up to 800 per event.
The modern experiments are propose to work at
unprecedented high multiplicities up to 8000
per unit rapidity - ALICE TPC (CERN/LHCC
2000001). Another example of the tracking system
is the STAR TPC which is able routinely
reconstructs more than 3000 tracks per one event
(M.Anderson et al., Nucl.Instr.Meth.A499 (2003)
659).
TPC operation parameters Centarl TPC -
diameter 5.6m - lenght 2.0m Forward TPC -
diameter 1 1.5m
diameter 2 5.0m - lenght 2.0m Drift time
-50?s
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The STAR TPC
MPD
A L I C E TDR of the Time Projection Chamber
The STAR detector contains a large, cylindrical,
Time Projection Chamber (TPC) as its primary
detector element. The TPC has an active volume
that extends from -1.8 to 1.8 units of
pseudo-rapidity with full azimuthal coverage. It
sits inside a large solenoidal magnet which is
designed to run with a .eld between 0 and 0.5 T.
The event multiplicities excess of 3000 tracks
per event. The momentum resolution is 2 at 500
MeV/c The two-track resolution for HBT pairs of
tracks is 2.5 cm. The dEdx resolution is
Excellent It able to separate the pion band and
the proton band at momenta up to 1.3 GeV/c and
the resolution is 7.5.
To cover this acceptance the TPC is of
cylindrical designwith an inner radius of about
80 cm, an outer radius of about 250 cm, and an
overall length in the beam direction of 500
cm. Two-track resolution a resolution in
relative momentum of a few (_ 5) MeV/c can be
performed. Resolution in dE/dx For hadron
identification a dE/dx resolution of 8 is
desirable, following the experience of NA49.
Track matching capability to ITS and TOF
Should be 8595. Electronics At about 570 000
channels the front-end electronics
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Particle identification with TPC An
strength of the tracker in solenoid magnetic
field at MPD is a large and uniform acceptance
capable to measure and to identify substantial
fraction of the particles produced in heavy-ion
collisions. For stable charged hadrons, the TPC
provides pions and kaons (protons) identification
up to pt 0.7 (1,1) GeV/c by ionization energy
loss (dE/dx). A TOF system with a time resolution
of lt100 ps is able to identify pions and kaons
(protons) up to pt 1.6 (3.0) GeV/c, as
demonstrated in Fig.. Combination of dE/dx in the
TPC and velocity measurements by TOF provides a
strong tool for the dilepton measurements.
MPD
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MPD
TRD
The Transition Radiation Detector (TRD) will
provide, in conjunction with data from the TPC
and EC detectors, sufficient electron
identification to measure, in the dielectron
channel, the production of light and heavy
vector-meson resonances for U-U collisions at the
NICA, as well as allow to study the dilepton
continuum. In addition, the electron
identification provided by the TPC and TRD at
relatively large transverse momenta (pt 1 GeV/c)
can be used, in conjunction with the
impact-parameter determination of electron tracks
in the ITS, to determine the overall amount of
open charm and open beauty produced in the
collision. With a similar technique one can also
separate directly produced J y mesons.
TRD system Design goals e/p discrimination of gt
100 (p gt 1 GeV/c) High rate capability up to 150
kHz/cm2 Position resolution of about 200 µm.
Large area (? 50m2, 3 layers)
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MPD
Electromagnetic Calorimeter. (EC)
Lead-Scintillator Calorimeter The
Pb-scintillator electromagnetic calorimeter is a
shashlik type samplingcalorimeter made of
alternating tiles of Pb and scintillator
consisting of 1500 individual towers and covering
an area of approximately 18 m2. The basic
building block is a module consisting of four
(optically isolated) towers which are read out
individually. The PbSc calorimeter has a nominal
energy resolution of 8.1/?E(GeV ) 2.1 and an
intrinsic timing resolution better than 200 ps
for electromagnetic showers
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MPD
ZDC
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Table 8.4. Schedule of MPD group II realization
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Summary
Mixed Phase Detector (MPD)

• - operate at the energy of beams 2.5 x 2.5 GeV/u
• - work at the luminosity of the heavy ion beams
  up to 1027 cm-2s-1 for UU
• - has practically 4? geometry
• - has minimum of passive matter in the detector
  volume
• - allow to measure high multiplicity events, up
  to 1000 particles/event
• - to separate e, ?, K, p particles in range
  200ltPlt2000 MeV/c
• - to measure lepton-pairs and ??-pairs
• This setup can be use for solution of
  fundamental scientific questions
• the nuclear matter equation-of-state at high
  baryonic densities
• the in-medium properties of hadrons
• space-time evolution of nuclear interaction
• the phase transitions
• the QCD critical endpoint
• Polarization studies at new facility

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Thanks for attention!
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