Aerogel Cherenkov counters for CBM

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Aerogel Cherenkov counters for CBM

• S.V.Afanasiev
• VBLHE JINR
• Dubna

GSI meeting 20-21 November 2003
Afanasiev S.V.
JINR Dubna
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The envisaged CBM physics program

• Signatures of chiral symmetry restoration.
  Probes Dilepton pairs, D mesons.
• The deconfinement phase transition. Probes
  charmonium, strangeness, collective flow.
• The critical point. Probes event-by-event
  fluctuations (K/pi ratio)
• Exotic states of matter. Probes strange and
  multistrange particles, K/p ratio

GSI meeting 20-21 November 2003
Afanasiev S.V.
JINR Dubna
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AEROGEL PROPERTIES

• Silica aerogels are a colloidal form of glass.
  They are solid, very light, transparent and
  refraction index can be in range 1.1 - 1.002.

Ya.Wang and W.L.Wolf, J.Opt.Soc.Am., Vol.73,
No.11 (1983)
GSI meeting 20-21 November 2003
Afanasiev S.V.
JINR Dubna
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Silica aerogels of low refractive index
(n1.012-1.028) arefound to be radiation-hard at
least up to 9.8 Mrad of gamma ray radiation.
S.K.Sahu et al. NIM A382(1996)
GSI meeting 20-21 November 2003
Afanasiev S.V.
JINR Dubna
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KEDR aerogel system

• 160 counters
• 800 liters of aerogel
• refractive index n1.05
• p and K separation in the momentum range 0.6 -
  1.5 GeV/c.

M.Yu.Barnykov et al., NIM. A 453(2000)
GSI meeting 20-21 November 2003
Afanasiev S.V.
JINR Dubna
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BELLE ACC

• 1188 counters
• 2000 litters of aerogel
• refractive index n1.03-1.01
• p and p separation in the momentum range up to
  3.5 GeV/c.

T.Sumiyoshi et al. J.Non-Crys. Sol. 225(1998)369
GSI meeting 20-21 November 2003
Afanasiev S.V.
JINR Dubna
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PHENIX ACC

• 160 counters
• 420 liters of aerogel
• refractive index n1.012
• K and p separation in the momentum range 0.2 -
  2.0 GeV/c.

M.Yu.Barnykov et al., NIM. A 453(2000)
GSI meeting 20-21 November 2003
Afanasiev S.V.
JINR Dubna
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GSI meeting 20-21 November 2003
Afanasiev S.V.
JINR Dubna
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The PHENIX ACC together with TOF can extend the
PID capability upto 10 GeV/c
GSI meeting 20-21 November 2003
Afanasiev S.V.
JINR Dubna
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JINR ACC test
Large TOF base for particle separation
Secondary particles p, p of the nuclotron beam
V.F.Peresedov et al. Proc. Of the RNP Int.
Workshop, Slovak Rep. Stara Lesna, 2003
GSI meeting 20-21 November 2003
Afanasiev S.V.
JINR Dubna
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Aerogel Signal for protons and pions
2 GeV/c
Pions
d
Proton
Protons
K
Pion

• Clear separation of protons and pions observed.

PID by TOF successful
GSI meeting 20-21 November 2003
Afanasiev S.V.
JINR Dubna
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Potentialities of ACC
To see the threshold momenta for the different
indices of AEROGEL, the expected number of
emitted photon are calculated through empirical
equation N p.e. 55 L 1-(1/nb2)
GSI meeting 20-21 November 2003
Afanasiev S.V.
JINR Dubna
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Particle density N/100 cm2 along the
horizontal axis (black line) and along
the vertical axis (red line) within 10 cm wide
windows which cross the center of the detector
GSI meeting 20-21 November 2003
Afanasiev S.V.
JINR Dubna
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Segmentation of Aerogel
Emission angle, charged particle density,
detector surface, pad size and number of cells
per aerogel layer. The numbers refer to a central
AuAu collision at 25 GeV/u and an occupancy
below 5.
GSI meeting 20-21 November 2003
Afanasiev S.V.
JINR Dubna
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Aerogel RICH
GSI meeting 20-21 November 2003
Afanasiev S.V.
JINR Dubna
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CONCLUSIONS
For study

• refractive index lt1.01
• physical and chemical properties

• refractive index 1.1 - 1.005
• radiation-hard
• stable
• compact size

The Aerogel Threshold Cherenkov detector can be
used as bridge between TOF and gas RICH
detectors
GSI meeting 20-21 November 2003
Afanasiev S.V.
JINR Dubna