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RICH 2007 highlights

Explore the production methods, properties, and history of silica aerogels used as Cherenkov radiators. Learn about density scans, machining possibilities, focusing optimization, and photon detectors.

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RICH 2007 highlights

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  1. 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:1992-2002 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 X-ray =0.156nm beamspot < 1mm

  6. Index Scan Study (2) preliminary value: • density relative uniformity (n-1)/(n-1) ~ +/-0.02 need further studies edge 109mm 109mm middle center 10.7mmt Density ratio(%) Index (Fraunhofer method at 405nm) = 1.0577 +/- 0.0006 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. √2 Sodium fluoride radiator Suggested for RICH with a TEA/TMAE pad-photon detector by R. Arnold et al. [ NIM A273 (1988) 466 ] • 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?

  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. Status and perspectives ofsolid state photon detectors for single photon detectionPixelated Photon Detector (PPD) Junji Haba, KEK RICH2007 @Trieste Junji Haba, KEK

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

  19. 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. Lorentz @PD07 For MAGIC collaboration

  20. Future improvements expected • Larger PDE • Wider Area • Lower Noise • Less crosstalk • Wider dynamic range • (and really cheaper price) RICH2007 @Trieste Junji Haba, KEK

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

  22. 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. Korpar@this WS H.G. Moser @PD7 RICH2007 @Trieste Junji Haba, KEK

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

  24. Less crosstalks • Separation trenches can help to reduce crosstalk rate. • There may be a side effect. Yamamoto@PD07 C. Piemonte@FNAL seminar RICH2007 @Trieste 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 Introduction Hybrid Photon Detectors Production Test results Conclusions LHCb HPD RICH 2007, Trieste, 17.10.2007 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) Stephan Eisenhardt

  27. Testing Programme – Summary result: pass: 547 ~98% fail: 12 ~ 2% 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 • <QE @ 270nm> = 30.8% >> typical QE = 23.3% <QE> per delivery batch QE [%] RMS of batch spread QE [%] Wavelength [nm] • more tuning improvements: • fill of sensitivity dip between UV and visible • reduction of red sensitivity @ 800nm • anti-correlated to blue sensitivity • cause of thermal e--emission (dark count) Batch number 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 Stephan Eisenhardt QE – DEP

  30. Commissioning of the LHCb RICH DetectorC. 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. Excellent! This is the distribution of the total number of phel per event (~2.4 Millions active channels). Number of photoelectrons FIAT LUX (first photons detected) 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)

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