23/02/07G. Vidal-Sitjes, VCI2007 Vienna Conference on Instrumentation1 The LHCb RICH detector G. Vidal-Sitjes on behalf of the LHCb RICH team Outline: The LHCb detector PID in LHCb The RICH counters in LHCb The Photon Detectors (HPDs) Performance and calibration

23/02/07G. Vidal-Sitjes, VCI2007 Vienna Conference on Instrumentation2 The LHCb detector 250 mrad 10 mrad Single arm spectrometer for precise CP Violation measurements and rare decays in the B-meson system at the LHC Vertex reconstruction: VELO Trigger: Muon Chambers Calorimeters Tracker PID: RICHs Calorimeters Muon Chambers Kinematics: Magnet Tracker Calorimeters

23/02/07G. Vidal-Sitjes, VCI2007 Vienna Conference on Instrumentation3 Need of PID with RICH Example: Need to distinguish B d   from other similar topology 2-body decays and to distinguish B from anti-B using K tag. Need of particle identification over momentum range GeV/c

23/02/07G. Vidal-Sitjes, VCI2007 Vienna Conference on Instrumentation4 2 RICHs and 3 radiators to cover phase space Silica Aerogel: n= GeV/c C 4 F 10 : n= Up to ~70 GeV/c CF 4 : n= Up to ~100 GeV/c RICH1 : 25  250 mrad vertical, 300 mrad horizontal RICH2 : 15  100 mrad vertical, 120 mrad horizontal

23/02/07G. Vidal-Sitjes, VCI2007 Vienna Conference on Instrumentation5 Spherical Mirror Flat Mirror Photon detector housing and magnetic shielding Central Tube Mirror Support Panel Support Structure Two RICH counters Spherical mirrors Flat mirrors Photon detector housing and shielding Beam pipe 4m 8m

23/02/07G. Vidal-Sitjes, VCI2007 Vienna Conference on Instrumentation6 RICH1 Gas vessel and optics < 6kg/m2 = 1.5% Xo R=2700 +/- 10 mm (specs /- 27mm) Total Area ~ 2m 2 D 0 ~0.5mm (specs D 0 <2.5mm) 0.5mm

23/02/07G. Vidal-Sitjes, VCI2007 Vienna Conference on Instrumentation7 RICH2 Gas vessel & Optics

23/02/07G. Vidal-Sitjes, VCI2007 Vienna Conference on Instrumentation8 The Pixel Hybrid Photon Detectors (HPD) ~2.9m 2 total surface Granularity: 2.5 x 2.5 mm 2 Active area coverage >65% Single-photon sensitivity between nm Magnetic fringe field (<25 G) Read-out: Compatible with LHC 40MHz bunch crossing frequency. 10% occupancy (worst case)

23/02/07G. Vidal-Sitjes, VCI2007 Vienna Conference on Instrumentation9 HPDs 75 mm active (81.7% tube) HPDs developed in close collaboration with industry (Photonis-DEP lead partner) Quartz window with S20 photocathode Cross focusing optics: 20 kV operating voltage Demagnification of ~5 Point Spread Function 250  m 484 tubes 256x32 subpixel sensor (0.0625x0.5 mm 2 each) Encapsulated binary electronics readout chip  -metal and Supra 36 shields 465 tubes already delivered 400 tested and ready to be used acceptance of >96% of tested tubes

23/02/07G. Vidal-Sitjes, VCI2007 Vienna Conference on Instrumentation10 shaper output 5000e - input 100ns 25 ns 500um 62.5 um The sensor and its read-out The analog signal 5000e max 20kV 25ns rise time  compatible with 40 MHz clock 100 ns tail  compatible with interaction rate & occupancy S/N ratio of 50 threshold 2000e Fast OR of 8 sub-pixels Binary pixel read-out (32x32) ANALOG BINARY threshold

23/02/07G. Vidal-Sitjes, VCI2007 Vienna Conference on Instrumentation11 HPD column mechanics Mirror Beam System tests

23/02/07G. Vidal-Sitjes, VCI2007 Vienna Conference on Instrumentation12 Electronics System (reviewed March 2004) RICH2 column On-detector Off-detector data fibres TTC fibres power cables control system DAQ link

23/02/07G. Vidal-Sitjes, VCI2007 Vienna Conference on Instrumentation13 Results of the system tests Photoelectron yield within 5% of expected Single-photon Cherenkov angle reconstruction MC and data chi2= 22.7/ Preliminary 2004

23/02/07G. Vidal-Sitjes, VCI2007 Vienna Conference on Instrumentation14 Expected performance of the RICH detectors AerogelC 4 F 10 CF 4 Chromatic Emission Point Pixel PSF Overall Single Cherenkov photon angle resolution (mrad) AerogelC 4 F 10 CF Simulated b events

23/02/07G. Vidal-Sitjes, VCI2007 Vienna Conference on Instrumentation15 CF 4 RICH1 RICH2 Reconstruction Algorithm starts with tracks and searches for hits assuming different hypotheses Global ring-fit

23/02/07G. Vidal-Sitjes, VCI2007 Vienna Conference on Instrumentation16 K      Particle Momentum (GeV/c) K  K or p   K or p   e,  or  K  e,  or  Particle Momentum (GeV/c) PID performance  identification K identification

23/02/07G. Vidal-Sitjes, VCI2007 Vienna Conference on Instrumentation17 Calibration 1: mirror misalignment Mirror alignment monitored continuously with laser system Precise alignment by data analysis aligned misaligned

23/02/07G. Vidal-Sitjes, VCI2007 Vienna Conference on Instrumentation18 Calibration 2: Magnetic distortions  B┴B┴ B║B║ Axial Transverse 30G CoilHPD LED & collimator used to produce pattern of light on HPD

23/02/07G. Vidal-Sitjes, VCI2007 Vienna Conference on Instrumentation19 Distortions modelled and measured Magnetic field at the locations of the HPDs has been measured at intervals of 10cm Effect of B on HPDs measured and modelled B inside HPDs is unknow System to project pattern of light onto HPDs with and without B field Calibration data. Lookup table. Azimutal distortionRadial distortion

23/02/07G. Vidal-Sitjes, VCI2007 Vienna Conference on Instrumentation20 Summary New technologies: –Large active area multi-pixel HPDs –Encapsulated 0.25  m-process bump-bonded read- out chip with 40 MHz clock –Carbon fibre mirror (~1.5% X 0 thick) PID from 1 to 100 GeV/c Excellent performance of tested HPDs All ingredients to PID performance simulations are measured quantities RICHs will be commissioned and ready to take data in 2007

23/02/07G. Vidal-Sitjes, VCI2007 Vienna Conference on Instrumentation21 Spare Slides

23/02/07G. Vidal-Sitjes, VCI2007 Vienna Conference on Instrumentation22 Anode manufacture Ceramic carrier Chip+sensor Glue Curing of XXX Wiring

23/02/07G. Vidal-Sitjes, VCI2007 Vienna Conference on Instrumentation23 Tube assembly VTT (Finland): bump bonding recipe using solder with high melting point (SnPb 10/90)

23/02/07G. Vidal-Sitjes, VCI2007 Vienna Conference on Instrumentation24 MgF 2 coating – reflectivity vs wavelength Left: 2 CMA CF runs CMA can meet our specs Above: SESO run using CF and glass 90%

23/02/07G. Vidal-Sitjes, VCI2007 Vienna Conference on Instrumentation25 MgF 2 - Reflectivity * QE vs energy Cherenkov yield: CMA= cf CERN (A.Braem/C.David)

23/02/07G. Vidal-Sitjes, VCI2007 Vienna Conference on Instrumentation26 MgF 2 - Reflectivity * QE vs energy Cherenkov yield: SESO = cf CERN (A.Braem/C.David) We have signed contract with SESO Coating in Feb 07