Detectors for VEPP2000

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Detectors for VEPP-2000
B.Khazin
Budker Institute of Nuclear Physics
2 March 2006
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VEPP-2000

• circumference 24.4 m
• revolution time 82 nsec
• beam current 0.2 A
• beam length 3.3 cm
• energy spread 0.7 MeV
• ?x ?z 6.3 cm
• L 1032 cm-2s-1 at 2E2.0 GeV
• L 1031 cm-2s-1 2E1.0 GeV

SND
Total integrated luminosity with all detectors on
VEPP-2M 70 pb-1
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Detector requirements

• Full solid angle
• High energy and coordinate resolutions for
  photons
• Perfect reconstruction of events with many
  charged
• particles
• K/?/µ separation
• Antineutron (neutron) identification

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Spherical Neutral Detector
1 VEPP-2000 vacuum chamber, 2 tracking
system, 3 aerogel counters, 4
electromagnetic calorimeter NaI(Tl), 5 vacuum
phototriodes, 6 absorber, 7-9 muon system,
10 VEPP-2000 phocusing solenoid
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Cryogenic Magnetic Detector-3
1 vacuum chamber 2 drift chamber 3
electromagnetic calorimeter BGO 4 Z chamber
5 CMD SC solenoid
6 electromagnetic calorimeter LXe 7
electromagnetic calorimeter CsI 8 yoke 9
VEPP-2000 solenoid
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Tracking system
SND tracking system - 24 jet cells, 9 drift
layers with s 0.2 mm - cathode strips on inner
and outer shells with s 0.3 mm - along wires
charge division with s 2 mm - MWPC on the
outside of drift layers - 0.27 g/cm2, 0.01 X0
, 0.005 lN , DW 0.75-0.95 4p
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Tracking system

• 1218 hexagonal cells ( 9 mm side)
• Sense wires - W-Re with 15 mcm diameter
• Field wires - gold plated Ti with 100 mcm
  diameter
• Gas mixture - Ar/isobutan (80/20)

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Calorimeter NaI(Tl)
Energy resolution
Angular reolution

• NaI(Tl) crystals
• Vacuum phototriodes

1680 NaI(Tl) crystals in 3 spherical layers
with vacuum phototriodes as photosensitive
devices weight 3.5 tons, thickness 13.5 X0 ?
0.9 4?
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End cap calorimeter BGO
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Calorimeter CsI
1152 crystals 6060150 mm3 8.1 X0 8
octants by 9 rows of 16 crystals HAMAMATSU
S2744-08-5B3 12 cm2
Counter (1152)
Row (72)
Octant (8)
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Calorimeter LXe
5.7 X0 of LXe (400 liters, 1.2 tons) 14 gaps by
10.2 mm 2124 coordinate strips 264 towers
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Barrel system resolution
CsI
CMD-2
LXe
CMD-3
LXeCsI
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Calorimeter LXe ? K separation
Energy depositions in successive gaps for
different momentum
Pions
100 MeV/c
200 MeV/c
300 MeV/c
400 MeV/c
600 MeV/c
500 MeV/c
700 MeV/c
800 MeV/c
900 MeV/c
?K?1.5
?K?2.5
?K?3.5
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Particle ID Aerogel Counters
e/p, p/K separation
Counter efficiency
Aerogel shifter PMT Aerogel thickness 31
mm Shifter turned by 5 Teflon coverage
(R0.98) Nucl.Instrum.Meth.A315517-520,1992
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Particle ID Timing Counter (SCiG)
Antineutron identification in ee??n n bar
Average number of photoelectrons per PMT
10 Time resolution s(TOF) 1 ns
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Conclusions

• New generation of detectors perfectly matches
• the reach physics potential of VEPP-2000
• Both detectors plan to the end of this year
• be ready to accept first luminosity