1. Focusing Aerogel RICH for PID and Momentum Measurement
A.Yu.Barnyakov, M.Yu.Barnyakov, V.S.Bobrovnikov, A.R.Buzykaev, V.V.Gulevich, S.A.Kononov, E.A.Kravchenko, A.P.Onuchin
Budker Institute of Nuclear Physics, Novosibirsk, Russia
A.F.Danilyuk
Boreskov Institute of Catalysis, Novosibirsk, Russia
Presented by E.A.Kravchenko

2. E.A.Kravchenko, "FARICH for PID and momentum measurement"
Outline
RICH with aerogel and additional high refractive index radiator
FARICH for SuperB Factory detector
FARICH for Super Charm-Tau Factory detector at Novosibirsk
FARICH prototype and test beam line for detector R&D
Conclusion
May 3-7, 2010
E.A.Kravchenko, "FARICH for PID and momentum measurement"

3. E.A.Kravchenko, "FARICH for PID and momentum measurement"
Why Aerogel?
The difference of Cherenkov angles for different particles is larger
Dispersion is smaller
The large number of detected photons from high refractive index radiators can not compensate these effects (~ 1/√Npe)
May 3-7, 2010
E.A.Kravchenko, "FARICH for PID and momentum measurement"

4. Aerogel disadvantages
Low light ~(1-1/n2)
6 times smaller than in quartz (for n=1.05)
Close to 100% light collection needed
High threshold Pth=m/√n2-1 =>
additional high refractive index radiator (water, NaF or others)
threshold counter mode
AEROGEL
NaF
May 3-7, 2010
E.A.Kravchenko, "FARICH for PID and momentum measurement"

5. E.A.Kravchenko, "FARICH for PID and momentum measurement"
SuperB Factory in LNF
Crab-waist scheme, L=1036cm-2s-1
e- longitudinal polarization
Collaboration expect government approvement in the nearest future
Damping ring
Detector hall
May 3-7, 2010
E.A.Kravchenko, "FARICH for PID and momentum measurement"

6. E.A.Kravchenko, "FARICH for PID and momentum measurement"
SuperB detector
TOFlike PID
Wide use of BaBar ideas, parts and experience
Serious work on detector geometry optimization
Several PID options in the forward
May 3-7, 2010
E.A.Kravchenko, "FARICH for PID and momentum measurement"

7. E.A.Kravchenko, "FARICH for PID and momentum measurement"
FARICH for SuperB
Expansion gap 180 mm
Burle MCP PMT with 6x6 mm pixels (8x8 matrix), photoelectron collection efficiency 70%, geometrical factor 70%
3-layer focusing aerogel, nmax=1.07, total thickness 40 mm,
NaF radiator, n=1.33, 10 mm thickness
Number of PMTs ~ 320
Number of channels ~ 20000
Amount of material, (X0) = 4%(aerogel)+ 10%(NaF)+ 14%(MCP PMT)+8% (support, electronics, cables) ~ 35%
May 3-7, 2010
E.A.Kravchenko, "FARICH for PID and momentum measurement"

8. FARICH expected performance (MC results)
[normal incidence, B = 0.T, MS off]
Npe = 17+32
σβ/β ≥ 8·10-4
additional effects of resolution degradation (Pπ=0.7GeV/c, βγ=5)
B=1.5T, MS off
0.1%
B=0. T, MS on 6%
B=1.5T, MS on
B=1.5T, MS off, dip angle 13°
18%
B=1.5T, MS on, dip angle 13°
32%
May 3-7, 2010
E.A.Kravchenko, "FARICH for PID and momentum measurement"

9. Super Charm-Tau Factory project at BINP (Novosibirsk)
Crab-waist scheme, L=1035 cm-2s-1
e- longitudinal polarization
E at c.m. from 2 to 5 GeV
Infrastructure partly exists (injector, part of tunnels)
Very close link in accelerator development with SuperB project
May 3-7, 2010
E.A.Kravchenko, "FARICH for PID and momentum measurement"

10. Super Charm-Tau detector
Standard set of subsystems (1-Vertex Detector, 2 – Drift Chamber, 3 – PID => FARICH, 4 – EMC, – Superconducting Solenoid, 6 – IFR)
Very promising signals from last contacts with Russian government for this project
May 3-7, 2010
E.A.Kravchenko, "FARICH for PID and momentum measurement"

11. Physics motivation for PID system
“golden” process is the search for lepton flavor violation in τ decays: τ→μγ (projected sensitivity Br ≤ 10-9)
main background is τ→ππ0ν (Br = 25%)
muon tagging of τ decays doubles tagging efficiency
powerful μ/π separation is needed below 1 GeV/c
(pion supression at the level 100 or better, muon system can not provide this)
=>This task is accessible only with a FARICH
May 3-7, 2010
E.A.Kravchenko, "FARICH for PID and momentum measurement"

12. FARICH for Super Charm-Tau detector
4π geometry
20 m2 of radiator and photon detectors
focusing aerogel
106 channels
SiPMs are the main candidate for the photon detector (gas filled photo-detectors with bialkali photo-cathode could be a cheap alternative?)
May 3-7, 2010
E.A.Kravchenko, "FARICH for PID and momentum measurement"

13. Monte Carlo simulation
Expansion gap 200 mm
Photon detector: Hamamatsu MPPC x3 mm, pitch 4.1 mm (fill factor 53%)
Radiator: 4-layer aerogel, (optimal focusing at Pπ=1 GeV/c) , nmax=1.07, total thickness 35 mm
Npe ≤ 23
σβ ≥ 4·10-4
May 3-7, 2010
E.A.Kravchenko, "FARICH for PID and momentum measurement"

14. Monte Carlo simulation
σP/P=γ2·σβ/β
σP/P≥ 1%
May 3-7, 2010
E.A.Kravchenko, "FARICH for PID and momentum measurement"

15. E.A.Kravchenko, "FARICH for PID and momentum measurement"
FARICH prototype
box designed for radiator-PD distance from 50 to 700 mm
32 MRS-APDs (SiPMs) as photon detectors
custom made discriminator boards
CAEN V1190B 64 channel multihit TDC
May 3-7, 2010
E.A.Kravchenko, "FARICH for PID and momentum measurement"

16. E.A.Kravchenko, "FARICH for PID and momentum measurement"
Prototype status
All SiPMs are tested (amplification, noise rate)
Tests of boards with discriminators are in progress
Tests with photo-diode are in progress
All components are available, assembly is in progress
The first beam tests in October 2010
May 3-7, 2010
E.A.Kravchenko, "FARICH for PID and momentum measurement"

17. Test beam at VEPP-4M, Novosibirsk
Emaxbeam = 5.5 GeV
Moving converter will be put in the beam halo to produce bremstrahlung gammas
Gamma-quanta are converted to electron-positron pairs in the target.
Magnet is used to select electrons (positrons) with the required energy.
May 3-7, 2010
E.A.Kravchenko, "FARICH for PID and momentum measurement"

18. E.A.Kravchenko, "FARICH for PID and momentum measurement"
Test beam apparatus
Magnet
Coordinate chambers
Veto and trigger counters
NaI calorimeter
FARICH prototype
May 3-7, 2010
E.A.Kravchenko, "FARICH for PID and momentum measurement"

19. Experimental hall with beam line components supports
May 3-7, 2010
E.A.Kravchenko, "FARICH for PID and momentum measurement"

20. Two coordinate movement system with remote control
May 3-7, 2010
E.A.Kravchenko, "FARICH for PID and momentum measurement"

21. Trigger and Veto scintillation counters
NaI calorimeter
May 3-7, 2010
E.A.Kravchenko, "FARICH for PID and momentum measurement"

22. E.A.Kravchenko, "FARICH for PID and momentum measurement"
Drift chambers
May 3-7, 2010
E.A.Kravchenko, "FARICH for PID and momentum measurement"

23. E.A.Kravchenko, "FARICH for PID and momentum measurement"
Conclusion
FARICH with additional NaF radiator is suggested for PID in the forward part of SuperB detector.
FARICH suggested for the Super Charm-Tau factory detector must provide exceptional level of particle identification.
The construction of the FARICH prototype and test beam facility is on the final stage. First experiments are foreseen at the end of 2010.
May 3-7, 2010
E.A.Kravchenko, "FARICH for PID and momentum measurement"

24. E.A.Kravchenko, "FARICH for PID and momentum measurement"
MRS APD parameters
Producer - Center of Perspective Technology and Apparatus – CPTA, Moscow
Genuine name - MRS APD (other names: silicon photomultiplier, PPD,MPPC…)
2.1x2.1 mm sensor
4x4 mm case size
600 nm
Gain ~ 4·105
Time resolution ~100 ps
Dark counts ~10 MHz (0.5pe threshold)
May 3-7, 2010
E.A.Kravchenko, "FARICH for PID and momentum measurement"