Software Development for the PANDA Barrel DIRC Dipanwita Dutta1,2 for the PANDA Cherenkov Group 1GSI Helmholtzzentrum für Schwerionenforschung GmbH, Darmstadt, Germany, 2 Bhabha Atomic Research Centre, Mumbai, India. Email: D.Dutta@gsi.de PANDA Experiment BABAR DIRC Principle Reconstruction Algorithm C PANDA: antiProton ANnihilation at DArmstadt Future FAIR Facility for Antiproton and Ion Research at GSI Cooled antiproton beam on proton and nuclear target The input for the Cherenkov angle reconstruction : Charged track parameter Hit time (t) and position (x,y) in photon detector plane Possible Reconstruction Algorithms: Babar-Like Reconstruction: Look-up table: (PMT/Bar define angle) Followed by likelihood method Calculate unbiased likelihood for hypothesis e///K/p track and background -Track maximum likelihood fit (track by track) individual track fit provides qc, s(qc), number of signal/background photons - Event global likelihood fit iterative process to maximize event likelihood, full correlation of all tracks Hough Transformation - Fit the ring directly, standard method for shape recognition PD plane Track DIRC: Detection of Internally Reflected Cherenkov Light BABAR-DIRC, first DIRC detector at SLAC B-factory Cherenkov radiation emitted when b = v/c > 1/n(l) Cherenkov Angle cos qc = 1/n(l) b Radiator bar from Synthetic Fused Silica n > 2 some photons are always totally internally reflected for b  1 tracks DIRC is intrinsically a 3-D device, measuring: x, y and time of Cherenkov photons, defining qc, fc, tpropagation of photon C Expansion medium C PANDA Barrel DIRC Study of QCD with Antiprotons Charmonium Spectroscopy Search for Exotic Hadrons in Medium Nucleon Structure Hypernuclear Physics .. and more Photon position and time (x,y,t) DIRC Reconstruction Bar Lens Mirror The PANDA Experiment at FAIR Panda Barrel DIRC p PANDA Barrel DIRC designed as a Fast Focusing DIRC Basic approach similar to BABAR-DIRC Improvements: Small pixel, faster timing, focusing optics Small photon detector pixels to decrease the size of expansion region Faster timing (~100 ps) to correct chromatic dispersion term Use focusing optics (lens or mirror) to decrease bar size term Fused Silica bar Correction of Chromatic Dispersion J. Schwiening, RICH 2007 Barrel DIRC Cherenkov angle production is controlled by nphase () cos c = 1/(nphase ()×b) ; c (red) < c (blue) (c) chromatic  5 mrad (for bialkali photo cathode) Propagation of photons is controlled by ngroup () vgroup = c0 /ngroup() = c0 /[nphase() –· dnphase() /d] ; vgroup(red) > vgroup (blue) Red photons arrive before Blue photons Particle ID in PANDA Particle identification essential for PANDA Wide momentum range, 200 MeV/c -10 GeV/c Different methods for PID needed PID Processes: Cherenkov radiation above 1 GeV Barrel DIRC Endcap Disc DIRC Energy loss below 1 GeV : TPC/STT Electromagnetic showers: EMC for e and  Time of flight K. Götzen, Troia 2009 The PANDA Experiment at FAIR The PANDA Experiment at FAIR PID Simulation for Barrel DIRC kaon efficiency 98% @ 2% π mis-ID Time Of Propagation (TOP)=LPath/vgroup() Track Expected PID performance example from simulation pp → J/Ψ Φ √s = 4.4 GeV/c2 C. Schwarz, RICH2007 DIRC Reconstruction Fused silica PANDA Barrel DIRC =0.69 _ Aim is to partially correct chromatic dispersion of Cherenkov angle by fast timing Realistic Hit Producer Future Plan Barrel DIRC Geometry A Realistic Hit Producer is being implemented for Barrel DIRC in PandaRoot which includes following realistic detector information motivated by the expected choice of photon detector (MCP PMT or gAPD): Pixelization of photon detector plane Pixel size of 6.5 mm × 6.5 mm Hits are center of pixel Convolution with detector efficiency of photocathode Wavelength dependent quantum efficiency of bialkali photocathode Gaussian smearing of time (time resolution =50 ps) Target pipe Study reconstruction algorithms and possibility of including DIRC for trigger (look up table) Implement chromatic dispersion correction Incorporate DIRC into global PID likelihood NLAK33A lens Beam pipe SiO2 lens Quartz bar Double lens structure for focusing in a plane Barrel DIRC In PandaRoot Results of Hit Producer Implementation of photon detection efficiency References PANDA Barrel DIRC Simulation Fused Silica Barrel PANDA Technical Progress Report, Feb, 2005; PANDA Physics Performance Report , arXiv:0903:3905v1 Development of the PANDA barrel DIRC, C. Schwarz , JINST 4, 12016 (2009) 3. Construction and Performance of the BaBar DIRC, J. Schwiening , JINST 4, 10004 (2009) Radiator barrel Lens in backward end Cherenkov light propagation in bar QE Expansion region Photon ring in photon detection plane Mirror in forward end Photon detection plane  (nm) Wavelength distribution of detected Cherenkov photons Quantum efficiency of Burle MCP PMT Photon time distribution Present Design of Barrel DIRC In PandaRoot Simulation for Focusing Optics Two lenses for flat focal plane Detected photon hits after det. eff. and pixelization 16 fold barrel geometry of radiators (Blue) Angular Coverage: 22-140 in  and 0-360 in  Radial Distance: 48 cm Each barbox is having 6 bar, total 96 bars Quartz Bar (Fused Silica of n=1.47) dimension:1.7 cm × 3.3 cm × 250 cm Mirror in forward end (Red) Double lens in backward end of quartz (Yellow and Brown) Photon Detection plane at a distance of 30 cm from the end of bar (Magenta) Photon Propagation Medium (Green) (presently Mineral oil) Expected number of pixels in PD plane7000-10000 PANDA barrel DIRC lens combination by ZEMAX simulation Focusing optics remove bar size contribution from Cherenkov angle resolution term Lens or mirror focusing Flat detection plane requires complex optics, study with ZEMAX optical system design software Two lenses, concave-convex (NLAK33A) and plane-convex (Fused silica), designed by ZEMAX and incorporated in PandaRoot DIRC Geometry XY distribution of MC points and detected hits in photon detection plane PANDA Barrel DIRC Simulation Photons directly reaching PD plane Barrel DIRC In PandaRoot Simulation with GEANT in PandaRoot BoxGen: Kaon, Mom 2 GeV, =50, =10 PANDA Barrel DIRC Prototype Photons after a reflection on lens MC points C. Schwarz, RICH 2007 RICH2010, Cassis, Provence, France, 3-7 May 2010 EU FP6 grant, contract number 515873, DIRAC secondary-Beams, and EU FP7 grant, contract number 227431, HadronPhysics2 and HIC for FAIR.