Aerogel Cherenkov counters for CBM

1. Aerogel Cherenkov counters for CBM S.V.Afanasiev VBLHE JINR Dubna GSI meeting 20-21 November 2003 Afanasiev S.V. JINR Dubna

2. 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

3. 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

4. Silica aerogels of low refractive index (n=1.012-1.028) 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

5. KEDR aerogel system • 160 counters • 800 liters of aerogel • refractive index n=1.05 • 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

6. BELLE ACC • 1188 counters • 2000 litters of aerogel • refractive index n=1.03-1.01 • 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

7. PHENIX ACC • 160 counters • 420 liters of aerogel • refractive index n=1.012 • 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

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

9. 0 0 0 0 0 0 4 4 4 4 4 4 8 8 8 8 8 8 p-K separation K-p separation TOF s~100 ps 0 - 2.5 - 5 RICH n=1.00044 5 - 17 17 - Aerogel n=1.012 1 - 5 5 - 9 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

10. 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

11. 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

12. Potentialitiesof 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

13. 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

14. 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 Au+Au collision at 25 GeV/u and an occupancy below 5%. GSI meeting 20-21 November 2003 Afanasiev S.V. JINR Dubna

15. Aerogel RICH GSI meeting 20-21 November 2003 Afanasiev S.V. JINR Dubna

16. refractive index 1.1 - 1.005 radiation-hard stable compact size refractive index <1.01 physical and chemical properties CONCLUSIONS For study 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