1. Antonis Papanestis RAL
RICH 2007 highlights
Antonis Papanestis
RAL

2. Study of a Silica Aerogel for a Cherenkov Radiator
Ichiro Adachi
KEK
representing for the Belle Aerogel RICH R&D group
2007 October 15-20
RICH2007, Trieste, Italy

3. Silica Aerogel Production
Production Method
Sol-gel process
nSi(OR)4 + 4nH2O  nSi(OH)4 + 4nH2O hydrolysis
nSi(OH)4  (SiO2)n + 2nH2O condensation
Chemical treatment to make hydrophobic
Supercritical drying
CO2 extraction method
31 degree Celsius and 7.5 MPa
Optical Quality
Transparency
T = T0*exp(-d/) where T is light intensity and d sample thickness
Refractive index measured with Fraunhofer method
These properties are strongly related to:
Chemical solvent
Mixing ratio between them
3 dimensional network

4. History of Aerogel Production
1st generation:1970’s-1980’s
TASSO/PETRA
1.025 ~ 1.055 50
III
2nd generation:
Belle Aerogel counter/KEKB
1.010 ~ 1.030
new production method
hydrophobic
transmission length at 400nm (mm) II 20
3rd generation:2002-
A-RICH for Belle upgrade
1.030 ~ 1.080
new solvent I
1.010
1.040
1.070
1.100
refractive index

5. Index Scan Study (1)
Relative weight for each composition in an aerogel was examined with XRF (X-ray fluorescence) analysis
X-ray tomography device was used to scan relative aerogel density difference Si
element Si O C
weight(%)
43.4%
50.6%
6.0%
X-ray =0.156nm
beam spot < 1mm

6. Index Scan Study (2) density relative uniformity
preliminary value:
(n-1)/(n-1) ~ +/-0.02
need further studies
edge
109mm
109mm
middle
center
10.7mmt
Density ratio(%)
Index (Fraunhofer method at 405nm)
= /
Distance from edge(mm)

7. Block Size Large sample produced Can be used for real detector
150 x 150 mm2 cross section
Thickness: 10 mm and 20 mm
“crack-free” rate by visual scan
n =1.050
110x110x20mm3
150x150x20mm3

8. Machining Possibility
Hydrophobic feature allows us to use “water-jet” cutter for machining
highly pressurized water injected via very small hole to a sample
hexagonal shape for two samples
110mm
150mm

9. Multiple-Layer Sample
two-layer sample with 160x160x20 mm3 has been successfully produced
one can use two aerogel layers as one unit
n = 1.045
n = 1.050
160mm
transmission length(400nm): 46mm
stress inside a tile well controlled
old
new

10. Focusing Aerogel RICH Optimization
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, V.L.Kirillov
Boreskov Institute of Catalysis, Novosibirsk, Russia
Presented by E.A.Kravchenko

11. Sodium fluoride radiator
Suggested for RICH with a TEA/TMAE pad-photon detector by
R. Arnold et al. [ NIM A273 (1988) 466 ] √2
Good transparency in visible & near UV,
Almost no light scattering as compared with aerogel,
More firm and stable material, though toxic.
NaF has the lowest refractive index among solids (except aerogel).
for λ >170 nm

12. Multilayer aerogel
100x100x41 mm, Lsc = 45 mm at 400 nm

13. Xray measurement, density distribution
The increase in density at the internal borders is the result of the production procedure (diffusion).
Does it effect the performance?
Layer
<n>
n, (optimal)
n, (design)
h, mm
h, mm (design) 1
1.046
1.050
12.6
12.5 2
1.041
1.040
1.044
13.2
13.3 3
1.037
1.035
1.039
15.2
14.2

14. Monte Carlo simulation of longitudinal refractive index fluctuations
200 mm expansion gap
3 types of radiators
3layer as designed (ideal)
Xray data avereged to 3 layers
Xray data avereged to 14 layers

15. Simulation results, π/K separation
Npe =14
σβ = 5∙10-4
‘optimal’ radiator → best resolution for 4 GeV/c pions
‘real’ experimental radiator → best resolution for 3.5 GeV/c kaons
π/K separation up to 8 GeV/c (>3σ)

16. Status of aerogel production
~2000 liters have been produced for KEDR ASHIPH detector, n=1.05
14 blocks 20020050 mm have been produced for LHCb RICH, n=1.03
~200 blocks 11511525 mm have been produced for AMS RICH, n=1.05
n=1.13 aerogel for SND ASHIPH detector
n=1.008 aerogel for the DIRAC
3-4 layers focusing aerogel
High optical parameters (Lsc≥43mm at 400 nm)
Precise dimensions (<0.2 mm)

17. RICH2007 @Trieste Junji Haba, KEK
Status and perspectives of solid state photon detectors for single photon detection Pixelated Photon Detector (PPD)
Junji Haba, KEK
Junji Haba, KEK

18. RICH2007 @Trieste Junji Haba, KEK
顕微鏡写真
H-１ｍｍ
H-３ｍｍ
受光面に関して、3mmと1mmとはほぼ同じに見えている
Junji Haba, KEK

19. For MAGIC collaboration
3. Test
Installation of 4 MPPC in front
Of the MAGIC camera
Trigger by air shower C-light
Comparison of signal in neighbor
Pmt cells (9 cm**2)
With 4 g-apd pixels (0.36 cm**2)
Readout by 2 Ghz F-ADC E.
For MAGIC collaboration

20. Future improvements expected
Larger PDE
Wider Area
Lower Noise
Less crosstalk
Wider dynamic range
(and really cheaper price)
Junji Haba, KEK

21. RICH2007 @Trieste Junji Haba, KEK
Larger PDE
Higher fill factor is a key
MRS(Metal Resitive Semiconductor) APD (CPTA)
Backside illumination &Drift (MPI)
Junji Haba, KEK

22. RICH2007 @Trieste Junji Haba, KEK
Wider area devices
1.3mm to 3 mm device test in progress at several places.
Higher noise though, as expected.
Light collection.
Drift type device (MPI)
S. WS
H.G.
Junji Haba, KEK

23. RICH2007 @Trieste Junji Haba, KEK
Less noise
Thinner epi layer (compromise long l sensitivity though)
Less defects. Epi quality or gettering technology.
Junji Haba, KEK

24. RICH2007 @Trieste Junji Haba, KEK
Less crosstalks
Separation trenches can help to reduce crosstalk rate.
There may be a side effect.
C. seminar
Junji Haba, KEK

25. Production and Tests of Hybrid Photon Detectors for the LHCb RICH Detectors
Stephan Eisenhardt, University of Edinburgh
On behalf of the LHCb experiment
LHCb
Introduction
Hybrid Photon Detectors
Production
Test results
Conclusions
HPD
RICH 2007, Trieste,
RICH2
RICH1

26. PDTF – Tests
Comprehensive test of every function and parameter of the HPD:
Electron Optics /
Tube Volume
Imaging
Demagnification
HV Stability
Field Distortions
Ion Feed Back
Vacuum Quality
Photocathode
Dark Count
Response to light
Quantum Efficiency
HPD Body
Dimensions
Quartz window
Pin Grid Array
Sensor position
Readout Chip
Connections
Communications
DAC linearity
Readout modes
Dead Channels
Noisy Channels
Pixel masking
Threshold
Noise
Silicon Sensor
IV Curve
Depletion
Bump-Bonding
Efficiency (Backpulse)
RICH 2007, Trieste,
Stephan Eisenhardt

27. Testing Programme – Summary
result:
pass: 547 ~98%
fail: 12 ~ 2%
RICH 2007, Trieste,
Stephan Eisenhardt

28. Quantum Efficiency – DEP Data
<QE> (DEP Data): across delivery batches
Excellent sensitivity:
increase due to process tuning at DEP
single most helpful improvement to RICH performance
270nm> = 30.8%
>> typical QE = 23.3%
<QE> per delivery batch
QE [%]
QE [%]
RMS of
batch spread
Wavelength [nm]
more tuning improvements:
fill of sensitivity dip between UV and visible
reduction of red 800nm
anti-correlated to blue sensitivity
cause of thermal e--emission (dark count)
Batch number
RICH 2007, Trieste,
Stephan Eisenhardt

29. QE – LHCb Verification PDTF measurement:
7 wavelengths, 10nm bandpass filter
error: 2%
76 HPD measured
PDTF QE measurements typically
matches DEP values within 3%
4 tests across QE range QE
all tests: PDTF vs. DEP
wavelength [nm]
PDTF measurements confirm
shape of spectra & absolute values
 full trust in DEP measurements
QE – PDTF
RICH 2007, Trieste,
Stephan Eisenhardt
QE – DEP

30. Commissioning of the LHCb RICH Detector C
Commissioning of the LHCb RICH Detector C. D’Ambrosio (CERN, Geneva, Switzerland) on behalf of the LHCb – RICH Collaboration
Outline
LHCb and its RICHes
What is Commissioning and Commissioning Strategy
RICH Commissioning, a (hi)Story
First Results
Conclusions and Outlook

31. Safety (…and more)
Regular Meetings (everyday coffees and weekly phone-conferences)
Hard and soft interlocks enabled from the beginning
Monitoring systems
Vessel, HPD boxes, electronics and electrics temperature, pressure and humidity sensors
Voltages and currents
Distributed and smart alerts, alarms, feedbacks and reactions
No development at the pit (at least we tried as much as we could…)
(see Mario)

32. RICH Starting Procedure
RICH2 ECS panel
DCS
DAQ (L0 & L1)
RICH2 Overview
…or the so called “one click startup”… (well, two clicks at the moment!)
HPD box
conditions

33. FIAT LUX (first photons detected)
Number of photoelectrons
Excellent!
This is the distribution of the total number of phel per event (~2.4 Millions active channels).
High Voltage was ramped very slowly and with the full system on, in order to monitor in real time the HPDs behaviour.
A red light emitting monomode fibre injects a controlled quantity of photons in the vessel

34. Social programme
Ratio social activities/talks ~ about right (50:50)