PANDA Collaboration At present a group of 340 physicists from 46 institutions of 14 countries Basel, Beijing, Bochum, Bonn, Catania, Cracow, Dresden, Edinburg, Erlangen, Ferrara, Frankfurt, Genova, Giessen, Glasgow, GSI, Inst. of Physics Helsinki, FZ Jülich, JINR, Katowice, Lanzhou, LNF, Mainz, Milano, Minsk, TU München, Münster, Northwestern, BINP Novosibirsk, Pavia, Piemonte Orientale, IPN Orsay, IHEP Protvino, PNPI St. Petersburg, Stockholm, Dep. A. Avogadro Torino, Dep. Fis. Sperimentale Torino, Torino Politecnico,Trieste, TSL Uppsala, Tübingen, Uppsala, Valencia, SINS Warsaw, TU Warsaw, AAS Wien http://www.gsi.de/panda Spokesperson: Ulrich Wiedner - Uppsala Austria – Belaruz - China - Finland - France - Germany – Italy – Poland – Russia – Spain - Sweden – Switzerland - U.K. – U.S.A.. 3 new members Unfortunately we lost KVI.
Main Physics Goals Charmonium spectroscopy QCD exotics Hypernuclear Physics Charm in Nuclei … base program for the first few years.
Target Envisaged luminosity: L = 2 × 10 32 cm –2 s –1 Required target thickness: 5 × 10 15 cm –2 Luminosity: L = N pbar f x target Cluster jet target. Hydrogen pellet target. Targets for hypernuclear physics.
Reminder: Droplets, Pellets, etc. Liquified hydrogen (H 2 ) Temp. 14.1 K (T f =13.96 K) Through nozzle (d~12 μ m) Droplets formed (d=38 μ m) Cooling by evaporation Vacuum injection, freezing: Droplets now called pellets (d~20 μ m) H 2 molecules The WASA Pellet TargetThe hydrogen path Liquid phase observed, before and after vac. inj. [m] 0.9 0.7 1.4
Pellet target: working principle and result 1 mm
Secondary target: sandwich of C absorber and Si detectors
The Electromagnetic Calorimeter Required: Fast, high resolution scintillator for between 10 MeV - 2 GeV Two possible solutions: PbWO 4 (PWO) crystals BGO crystals lower light yield slower and more expensive Crystal size: 2 2 cm 2 22 X 0
PWO crystals light yield of PANDA crystals better than as CMS crystals
For comparison: BGO crystals 60 Co Light yield ~ 8 times higher than PWO
Readout device: APD CMS uses 5x5 mm 2 APDs For PANDA: 10x10 mm 2 APDs being developed by Hamamatsu Preliminary tests show no significant differences. Alternative readout devices like the PLANACON hybrid photomultiplier have been tested but show sensitivity to magnetic fields.
Expected performance (PWO calorimeter) Measurements with a tagged photon beam in Mainz: deposited energy / GeV t / ns
The Mechanical Design Barrel part: 2.5 m long, Ø 1.08 m, 11360 crystals End caps: upstream: Ø 0.68 m, 816 crystals downstream: Ø ~2 m, 6864 crystals Cooling to -25 C, temperature stabilized to ±0.1 C