1. Particle Identification in LHCb
On behalf of the LHCb collaboration
Participating countries to the RICH
construction: CERN, ITALY, UK
INSTR02 March 2002
Clara Matteuzzi

2. The LHCb detector Forward single-arm spectrometer p-p collisions
14 TeV at LHC
Acceptance:
mrad
(bending plane)
mrad
(non-bending plane)
INSTR02 March 2002
Clara Matteuzzi

3. The LHCb detector Located in Pit 8 Interaction point
Local luminosity 2 x 1032
INSTR02 March 2002
Clara Matteuzzi

4. Physics with Particle Identification
Bs K+K-
Purity=84%
Efficiency=79%
Purity=13%
INSTR02 March 2002
Clara Matteuzzi

5. Physics with Particle Identification
Bs Ds K
Purity=7.0%
Purity=66% , efficiency=88%
INSTR02 March 2002
Clara Matteuzzi

6. Physics with Particle Identification
Momentum
Particle ID required from 1 to 150 GeV
2 detectors with
3 radiators
INSTR02 March 2002
Clara Matteuzzi

7. The RICH of LHCb 5 cm aerogel 4 m3 C4F10 RICH 1 RICH 2 100 m3 CF4
INSTR02 March 2002
Clara Matteuzzi

8. The RICH of LHCb Acceptance : 300 mrad RICH 1 120 mrad RICH 2 Mirrors:
spherical (R=170 cm and 800 cm)
tilted to place photodetectors
outside acceptance
plane mirrors necessary in RICH 2
INSTR02 March 2002
Clara Matteuzzi

9. Range of identification
The RICH of LHCb
Range of identification
2 – 11 GeV
10 –70 GeV
17 – 150 GeV
INSTR02 March 2002
Clara Matteuzzi

10. The RICH of LHCb Characteristics of the detectors: RICH 2 RICH 1
Radiators
properties
Cherenkov
Angle
precision
Photoelectron
yield
INSTR02 March 2002
Clara Matteuzzi

11. The RICH of LHCb HybridPhotoDiodes The PhotoDetectors requirements:
cover an area 2.6 m2
single photoelectron sensitivity
Quantum Efficiency > 20%
200 – 600 nm
granularity 2.5 x 2.5 mm2
large active area 75%
LHC speed read-out MHz
Baseline:
HybridPhotoDiodes
(HPD)
Backup:
Multianode PM
(MaPMT)
INSTR02 March 2002
Clara Matteuzzi

12. The HybridPhotoDiodes
Tube and encapsulation:
industry (DEP)
61 pixel HPD
INSTR02 March 2002
Clara Matteuzzi

13. The HybridPhotoDiodes
Pixel-HPD
Photocathode diameter 75 mm
Overall 83 mm diameter
PC voltage -20 KV e signal at Si anode
Electron optics: cross-focussed demagnification 5
Anode: Si pixel detector, bump bonded to pixel readout chip
pixel=50 mm x 500 mm (320x32 matrix)
pixel size at photocathode 2.5 x 2.5 mm2
1024 pixel
82% active area
168 HPDs in RICH1
262 HPDs in RICH2
340K electronic channels
INSTR02 March 2002
Clara Matteuzzi

14. AEROGEL as Cerenkov radiator
very light, solid quartz-like structure SiO2
low density around 0.15 g/cm3
refractive index n = r
transparent in the visible region
can be hydroscopic or hydrophobic
INSTR02 March 2002
Clara Matteuzzi

15. AEROGEL as Cerenkov radiator
TRANSMITTANCE:
Novosibirsk aerogel
T = A e (-C t / l4)
4 cm
T (%)
8 cm
A is the long l transmittance
C is the clarity coefficient
Index of refraction:
n =
n =
l (nm)
INSTR02 March 2002
Clara Matteuzzi

16. AEROGEL C = 0.0045-0.0065 T = 35% for 4 cm tile at 400 nm
Boreskov Inst. Catalysis
(Novosibirsk)
C =
mm4 cm-1
T = 35% for 4 cm tile at 400 nm
C = mm4 cm-1
T = 38% for 2 cm tile at 400 nm
SP30 Matsushita Electric,Japan
INSTR02 March 2002
Clara Matteuzzi

17. AEROGEL Ageing test (g) Source of radiation: 60 Co
Eg = 1.3 MeV , 1.7 MeV
Dose : rad/min
INSTR02 March 2002
Clara Matteuzzi

18. Ageing test (g) Ageing test No degradation up to the dose measured
INSTR02 March 2002
Clara Matteuzzi

19. AEROGEL Ageing test with protons -15% in the range shown
1 year LHCb operation
Source of radiation:
Proton beam 24 GeV
Fluence : p/cm2/s
Spot : 2 x 2 cm2
INSTR02 March 2002
Clara Matteuzzi

20. AEROGEL Humidity test Expose tile to humid air
Measure humidity absorption
through weight
Measure Transmittance
in range nm
INSTR02 March 2002
Clara Matteuzzi

21. AEROGEL Humidity test Loss of 30% at 300 nm Loss of 15% at 400 nm
INSTR02 March 2002
Clara Matteuzzi

22. AEROGEL as Cerenkov radiator
Test Beam
Beam from CERN-PS (T7 line)
1 – 10 GeV/c (dp/p=1%)
Negative : p-
Positive : p+ with protons (50 – 70%)
INSTR02 March 2002
Clara Matteuzzi

23. AEROGEL
Test Beam
INSTR02 March 2002
Clara Matteuzzi

24. 4 large Hybrid PhotoDetector
AEROGEL test beam
The PhotoDetectors
4 large Hybrid PhotoDetector
Bialkali photocathodes (K2CsSb)
2 electrodes: fountain shape electric field
2048 Silicon pads 1x1 mm2
16 sectors = 128 pads
demagnification factor 2.3
INSTR02 March 2002
Clara Matteuzzi

25. Quantum Efficiency of the 4 photocathodes > 20% for l=280-380 nm
AEROGEL test beam
The PhotoDetectors
Quantum Efficiency of the
4 photocathodes
> 20% for l= nm
One HPD
INSTR02 March 2002
Clara Matteuzzi

26. MONTECARLO Simulation Simulate Cherenkov radiation
AEROGEL test beam
MONTECARLO Simulation
Simulate Cherenkov radiation
in aerogel with GEANT 4
photons
Rayleigh scattering
Refraction on the bounderies
Light absorption
Light detection in photocathode
Photocathode transparency
etc
INSTR02 March 2002
Clara Matteuzzi

27. RESULTS (preliminary) Signal definition
AEROGEL test beam
RESULTS (preliminary)
Signal definition
Filters at exit window
ADC counts
INSTR02 March 2002
Clara Matteuzzi

28. Aerogel Novosibirsk Matsushita 4 cm 8 cm AEROGEL test beam
RESULTS - resolution
-- DATA
-- MC
Cerenkov angle in mrad
DATA and MONTECARLO
Aerogel
Novosibirsk
Matsushita
4 cm
8 cm
Cerenkov Radius (mm)
INSTR02 March 2002
Clara Matteuzzi

29. beam AEROGEL test beam RESULTS - resolution 9 GeV p- Clara Matteuzzi
INSTR02 March 2002
Clara Matteuzzi

30. No filter Filter D263 DATA 8.3 +- 0.4 5.6 +- 0.3 MONTE CARLO
AEROGEL test beam
RESULTS - Npe yield
4 cm thick aerogel from Novosibirsk
No filter
Filter D263
DATA
MONTE
CARLO
INSTR02 March 2002
Clara Matteuzzi

31. p / p separation AEROGEL test beam RESULTS 5.8 s 3.3 s 2.8 s 6 GeV
INSTR02 March 2002
Clara Matteuzzi

32. Conclusions RICH is essential for b-physics program of LHCb
The RICH design of LHCb with 2 detectors and
3 radiators allows 3s p-k separation in 2 – 80 GeV range
LHCb RICH project is progressing
The design of the subsystems are advanced
transition from R&D to construction is approaching
The detector will be in time to take data at day 1
of LHC
INSTR02 March 2002
Clara Matteuzzi