The DIRC projects of the PANDA experiment at FAIR Klaus Föhl on behalf of the Work supported by EU FP6 grant contract number 515837 DIRACsecondary-Beams RICH2007 Trieste, Italy October 2007 Cherenkov Group Darmstadt Dubna Edinburgh Erlangen Ferrara Giessen Glasgow Krakow Wien

Antiprotons HESR Hadron spectroscopy Nuclei Far From Stability - Charmonium spectroscopy - Gluonic excitations (hybrids, glueballs) Charmed hadrons in nuclear matter Double -Hypernuclei Nuclei Far From Stability Compressed Nuclear Matter High Energy Density in Bulk Antiprotons

A View of PANDA AntiProton ANnihilations at DArmstadt p Forward Spectrometer Target Spectrometer p

A View of PANDA AntiProton ANnihilations at DArmstadt High Rates 2 107 interaction/s Vertexing KS0, Y, D, … Charged particle ID e±, μ±, π±, K, p,… Magnetic tracking EM. Calorimetry γ,π0,η Forward capabilities leading particles Sophisticated Triggers

Particle ID & Kinematics pp i.e. open charm production pp  KK T=5,10,15 GeV/c + K      K K    K even or K     - + D pp  DD D  Kpp T=6.6 GeV/c distinguish  and K (K and p) ...

PANDA Target Spectrometer Acceptance for pp  h  @ 15 GeV End- cap Barrel Endcap Barrel PANDA: 4 detector desire to keep EMC small  hence we suggest DIRCs FS Target Spectrometer two areas – two detector geometries

...shipping coal to Newcastle... ...talking about DIRC at RICH...

DIRC Principles <1 =1 Detector of Reflected lower p threshold Internally Reflected Cherenkov light lower p threshold n p K  solid DIRC n=1.47 <1  =1  K p 15 deg <1 Time-of-Propagation for C fused silica 10mm 0.4eV =1

Barrel DIRC Barrel-DIRC BaBar-like 2D + t or (2+1)D design 2-dimensional imaging type Poster  Carsten Schwarz: The Barrel DIRC of the PANDA experiment

PANDA barrel DIRC scaled BaBar version suits PANDA “only” 7000 PMT (BaBar 11000 PMT) Simulations pp →J/ψ Φ √s = 4.4 GeV/c2 kaon efficiency 98% π misidentification as kaon 1-2%

PANDA barrel DIRC R&D towards smaller photon detector needs optical elements instead of pinhole focus mirrors lenses focal plane detector two lenses for flat focal plane Oil H2O air SiO2 quartz bar air mirrors

PANDA barrel DIRC y x fused silica close to threshold: β=0.69 small variations in n(λ) cause large δΘ cos(Θ)=1 / βn(λ) β=0.72 Time of Propagation (TOP) measurement better 0.5ns allows to correct dispersion for high and low momenta→x,y,t→3D-DIRC x Y

PANDA Target Spectrometer Two different readout designs: Time-of-Propagation Focussing Lightguide (1+1)D design 2D + t design Endcap Disc DIRC 1-dimensional imaging type Poster  Peter Schönmeier: The Endcap DIRC of the PANDA experiment

Dispersion Corrections different directions for different colours ToP for a given time t different horizontal distances for different photon colours Focussing – Solution: ToP – Solution: relevant for ToP narrow bands in wavelength dispersive prism component

Time-of-Propagation design colour filters dichroic mirrors as colour filters allows two wavelength bands higher photon statistics small wavelength bands minimise dispersion effect +optimised photocathodes mirrors mirrors give different path lengths  self timing design reflect some photons several different path lengths mirrors allow longer path lengths  better relative time resolution 20mm fused silica radiator disc single photon resolution t~30-50ps required

Time-of-Propagation design larger text 0 reflections 1 reflection 2 reflections 3 reflections 50 events time-of-propagation [ns]  [deg]

Time-of-Propagation particle angle 15 deg t=50ps E x QE=(0.18+0.2)eV disc with black hole

Focussing Lightguide * * * * radiator edge LiF SiO2 photo sensor strips fused silica (SiO2) radiator 10-15mm * discrete lightguide no. * angle in (r-z) plane LiF for dispersion correction photon extraction into lightguide lifts up-down direction ambiguity focussing inside lightguide * * lightguides

Focussing & Chromatic Correction no mirror coating 1-dim aspheric surface total internal reflection angle independent of  not-perfect focussing as curvature is compromise (but good enough) light is only going upwards two boundary surfaces make chromatic dispersion correction angle-independent in first order light never leaves dense optical medium  good for phase space Focal Plane (dispersive direction) 1-dimensional readout

Focussing Lightguide simulation example with 2 fit analysis target vertex  0  [deg] 360 simulation example with 2 fit analysis disc 10mm thick, 0.4eV short lightguide 125mm, focal plane 48mm

Research & Development Polishing Effectiveness Radiator Tests Radiation Hardness Photon Detectors AFM 30m x 30 m 5.46 nm full vertical scale Friday  Matthias Hoek: Radiation Hardness Study on Fused Silica magnetic field (up to B=2T), photon rate (MHz/pixel), light cumulative dose, radiation dose Thursday  Albert Lehmann: Performance Studies of Microchannel Plate PMTs in High Magnetic Fields

Summary High antiproton rates require novel detectors for PID We propose DIRCs for the PANDA Target Spectrometer FS TS Several designs with innovative solutions Barrel DIRC with optical elements Endcap DIRC – Time-of-Propagation Endcap DIRC – Focussing Lightguide R&D in progress

Panda Participating Institutes more than 300 physicists (48 institutes) from 15 countries U Basel IHEP Beijing U Bochum U Bonn U & INFN Brescia U & INFN Catania U Cracow GSI Darmstadt TU Dresden JINR Dubna (LIT,LPP,VBLHE) U Edinburgh U Erlangen NWU Evanston U & INFN Ferrara U Frankfurt LNF-INFN Frascati U & INFN Genova U Glasgow U Gießen KVI Groningen U Helsinki IKP Jülich I + II U Katowice IMP Lanzhou U Mainz U & Politecnico & INFN Milano U Minsk TU München U Münster BINP Novosibirsk LAL Orsay U Pavia IHEP Protvino PNPI Gatchina U of Silesia U Stockholm KTH Stockholm U & INFN Torino Politechnico di Torino U Oriente, Torino U & INFN Trieste U Tübingen U & TSL Uppsala U Valencia IMEP Vienna SINS Warsaw U Warsaw