Bernd Lewandowski RuhrUniversitt Bochum SCINT 2003 Valencia 11

Bernd Lewandowski Ruhr-Universität Bochum SCINT 2003 Valencia 11. 9. 2003 A Fast and Compact Electromagnetic Calorimeter for the Detector at GSI 11. 9. 2003

What is PANDA? Anti. Proton ANnihilations at DArmstadt 11. 9. 2003 Bernd Lewandowski - Ruhr-Universität Bochum - SCINT 2003 2

Where is Darmstadt? GSI 11. 9. 2003 Bernd Lewandowski - Ruhr-Universität Bochum - SCINT 2003 3

The GSI Future Facility Panda Existing GSI Facilities 11. 9. 2003 Bernd Lewandowski - Ruhr-Universität Bochum - SCINT 2003 4

Antiproton Physics Program Charmonium (cc ) spectroscopy: precision measurements of mass, width, decay branches of all charmonium states, especially for extracting information on qq models of mesons. 11. 9. 2003 Bernd Lewandowski - Ruhr-Universität Bochum - SCINT 2003 5

Antiproton Physics Program Charmonium (cc ) spectroscopy: precision measurements of mass, width, decay branches of all charmonium states, especially for extracting information on qq models of mesons. Search for gluonic excitations (charmed hybrids, glueballs) in the charmonium mass range (3 – 5 Ge. V/c 2). 11. 9. 2003 Bernd Lewandowski - Ruhr-Universität Bochum - SCINT 2003 6

Antiproton Physics Program Charmonium (cc ) spectroscopy: precision measurements of mass, pionic atoms width, decay branches of all charmonium states, especially for extracting information on qq models of mesons. π KAOS/FOPI Search for gluonic excitations (charmed hybrids, glueballs) in the charmonium mass range (3 – 5 Ge. V/c 2). K Search for modifications of meson properties in the nuclear medium, and their possible relationship to the partial restoration of chiral HESR symmetry for light quarks. π25 Me. V π+ K+ 100 Me. V K- D D 50 Me. V D+ vacuum nuclear medium ρ = ρ0 11. 9. 2003 Bernd Lewandowski - Ruhr-Universität Bochum - SCINT 2003 7

KK Antiproton Physics Program p Trigger _ Charmonium (cc ) spectroscopy: precision measurements of mass, width, decay branches of all charmonium states, especially for extracting 3 Ge. V/c information on qq models of mesons. - Search for gluonic excitations (charmed hybrids, glueballs) in the charmonium mass range (3 – 5 Ge. V/c 2). Search for modifications of mesontarget properties in the nuclear medium, secondary and their possible relationship to the partial restoration of chiral symmetry for light quarks. X-(dss) p(uud) → L(uds) vacuumnuclear medium p K p 25+ Me. V p K+ 100 Me. V K- D D 50+Me. V D Precision g-ray spectroscopy of single and double hypernuclei for Extracting information on their structure and on the hyperon-nucleon and hyperon-hyperon interaction. 11. 9. 2003 Bernd Lewandowski - Ruhr-Universität Bochum - SCINT 2003 8

The Antiproton Facility 11. 9. 2003 Bernd Lewandowski - Ruhr-Universität Bochum - SCINT 2003 9

The Antiproton Facility • Antiproton production similar to CERN, • HESR = High Energy Storage Ring – Production rate 107/sec – Pbeam = 1. 5 - 15 Ge. V/c – Nstored = 5 x 1010 p • Gas-Jet (or Cluster) Target • High luminosity mode – Luminosity = 2 x 1032 cm-2 s-1 – p/p ~ 10 -4 (stochastic cooling) • High resolution mode – p/p ~ 10 -5 (electron cooling < 8 Ge. V/c) – Luminosity = 1031 cm-2 s-1 11. 9. 2003 Bernd Lewandowski - Ruhr-Universität Bochum - SCINT 2003 10

Proposed Detector (Overview) • High Rates – Total s ~ 55 mb – 107 interactions/s • Vertexing – (sp, KS, L, …) • Charged particle ID – (e±, m±, ±, p, …) • Magnetic tracking • Elm. Calorimetry – (g, 0, h) • Forward capabilities – (leading particles) • Sophisticated Trigger(s) 11. 9. 2003 Bernd Lewandowski - Ruhr-Universität Bochum - SCINT 2003 11

Electromagnetic Calorimeter Detector material Pb. WO 4 Photo sensors Avalanche Photo Diodes Crystal size 35 x 150 mm 3 (i. e 1. 5 x 1. 5 RM 2 x 17 X 0) Energy resolution 1. 54 % / E[Ge. V] + 0. 3 % (PMT) Time resolution s 130 ps (PMT) Total number of crystals 7150 11. 9. 2003 Bernd Lewandowski - Ruhr-Universität Bochum - SCINT 2003 12

Requirements for the EMC • Nearly 4 solid angle (PWA) • High rate capability: 107 interactions/s • High resolution: 1. 54 % / E[Ge. V] + 0. 3 % • Compact design: inside Solenoid • Operation in magnetic field: 2 T 11. 9. 2003 Bernd Lewandowski - Ruhr-Universität Bochum - SCINT 2003 13

Lessons from LEAR (CB) • Final states with 10+ photons • Merged 0 are easy to handle – “moderate” angular resolution sufficient • Low thresholds Crystal Barrel – Emin≤ 20 Me. V 11. 9. 2003 Bernd Lewandowski - Ruhr-Universität Bochum - SCINT 2003 14

Available Inorganic Scintillators Property Cs. I(Tl) Ce. F 3 Pb. WO 4 BGO Density[g/cm 3] 4. 53 6. 16 8. 28 7. 13 Rad. length [cm] 1. 85 1. 68 0. 89 1. 12 Molière rad [cm] 3. 8 2. 63 2. 19 2. 33 d. E/dx [Me. V/cm] 5. 6 7. 9 13. 0 9. 2 Decay time [ns] 1000 10 -30 5 -15 60 -300 Max. emission [nm] 565 310 -340 420 -440 480 Rel. lightyield 0. 40 0. 10 0. 01 0. 15 11. 9. 2003 Bernd Lewandowski - Ruhr-Universität Bochum - SCINT 2003 15

PWO • Fast Scintillator • Allowsa very compactdesign • Low cost material • But: light yield too low for detection of low energy photons • Improvementof lightyield • Cooling(LY changeswith temperature ) 11. 9. 2003 Bernd Lewandowski - Ruhr-Universität Bochum - SCINT 2003 16

PWO Improvement counts photonresponse: Eg = 45 -770 Me. V@MAMI Eg=45. 4 Me. V Eg=105. 6 Me. V s/E=7. 4% s/E=5. 3% energy / a. u. R. Novotny et al. , II. Phys. Inst. GI PMT readout Bogoroditsk TCP furthersignificantincreaseof lightoutput achievableby: • improvement of growing technology PWO II (exploiting large experience with CMS/ECAL production) • optimum co-doping CMS/ECAL 11. 9. 2003 Bernd Lewandowski - Ruhr-Universität Bochum - SCINT 2003 17

PWO Improvement crystal imperfections : • • cation vacancies(Pb) anion vacancies(O) insite oxygen excess of dopingions resultsbased on EPR: M. Korzhiket al. , RINC, Minsk A. Hofstaetteret al. , I. Phys. Inst. GI • Frenkeldefectsreduced( factor >3) • Pt identified- impact on quenching? • oxygen based defectsreduced 137 Cs: L. Y. : 43 phe/Me. V „ 2 times CMS-standard “ @ T = 20°C 11. 9. 2003 Bernd Lewandowski - Ruhr-Universität Bochum - SCINT 2003 18

PWO Cooling line shape: @T=200 C 1= 6. 5 ns (97%) 2=30. 4 ns ( 3%) R. Novotny et al. , II. Phys. Inst. GI fraction of light yield collected in different integration gates at various temperatures change of light yield collected within 100 ns as a function of temperature 11. 9. 2003 Bernd Lewandowski - Ruhr-Universität Bochum - SCINT 2003 19

PWO Future Ongoing developements in PWO production will increase the light yield. Light yield improvement of PWO scintillation crystals for the PANDA detector A. Borisevich, V. Dormenev, A. Hofstaetter , V. Ligoun, M. Kozhik, B. K. Meyer, R. Novotny Combined with cooling and maximum coverage of readout side by photosensor can make PWO the scintillator of choice for the PANDA EMC. 11. 9. 2003 Bernd Lewandowski - Ruhr-Universität Bochum - SCINT 2003 20

Photosensor APD Hamamatsu. S 8664 -55 5 mm • „Photodiode with internal amplification“ • operates in B-Field • High quantum efficiency • Active area 5 x 5 mm 2 • Large experience with CMS/ECAL Extremely reliable and robust • but: gain, dark current are temp. dependend T < 1°C Others to be investigated : • Large Area APDs of other manufacturers • Channel Plate Multipliers • Vacuum Triodes, … 11. 9. 2003 Bernd Lewandowski - Ruhr-Universität Bochum - SCINT 2003 21

APD readout: Cs. I(Tl) @ T = 0 °C APD (Hamamatsu) readout active area: (5 x 5) mm 2 active area: Ø 10 mm 60 mm 662 ke. V PMT ( R 1635 ) readout Entries 137 Cs 50 mm 662 ke. V ADC channel 11. 9. 2003 Bernd Lewandowski - Ruhr-Universität Bochum - SCINT 2003 50 mm ADC channel 22

APD Quantum Efficiency BGO Cs. I(Tl) PWO Ce. F 3 11. 9. 2003 Bernd Lewandowski - Ruhr-Universität Bochum - SCINT 2003 23

Available Inorganic Scintillators Property Cs. I(Tl) Ce. F 3 Pb. WO 4 BGO Density[g/cm 3] 4. 53 6. 16 8. 28 7. 13 Rad. length [cm] 1. 85 1. 68 0. 89 1. 12 Molière rad [cm] 3. 8 2. 63 2. 19 2. 33 d. E/dx [Me. V/cm] 5. 6 7. 9 13. 0 9. 2 Decay time [ns] 1000 10 -30 5 -15 60 -300 Max. emission [nm] 565 310 -340 420 -440 480 Rel. lightyield 0. 40 0. 10 0. 01 0. 15 We‘ll come back to this in a minute. 11. 9. 2003 Bernd Lewandowski - Ruhr-Universität Bochum - SCINT 2003 24

BGO First tests with L 3 crystals: APD readout Temp controlled environment T=1°C controlledhumidity 30% rel. 11. 9. 2003 Bernd Lewandowski - Ruhr-Universität Bochum - SCINT 2003 25

APD readout: BGO T=0°C PMT R 1635 25 mm 1275 ke. V 22 Na 25 mm 511 ke. V Entries 22 Na 25 mm Entries APD 511 ke. V 1275 ke. V ADC channel 11. 9. 2003 25 mm Bernd Lewandowski - Ruhr-Universität Bochum - SCINT 2003 ADC channel 26

BGO time resolution PANDA: • 107 events/s 10 ns time resolution • MC: max. single crystal rate: ~200· 103/s BGO timing test: • L 3 BGO crystal • Hamamatsu APD • BABAR preamp (250 ns shaping) • Digital Scope • Record a sample of cosmics signals (~15 Me. V) Make a simple MC test 11. 9. 2003 Bernd Lewandowski - Ruhr-Universität Bochum - SCINT 2003 27

BGO time resolution • Use Landau func. to simulate pulses Landau fit + DC offset • Typical: N/S=0. 5% Vary S/N and FADC sampling freq. • Linear fit of rising edge • Determine time when fit reaches half the signal amplitude 11. 9. 2003 BGO Linear fit point of time measurement Bernd Lewandowski - Ruhr-Universität Bochum - SCINT 2003 28

BGO time resolution σv [V] 0. 01 0. 02 0. 03 0. 04 11. 9. 2003 N/S [%] 0. 5 1. 0 2. 0 5. 0 ΔTSamples [ns] 100 100 200 200 50 50 σt [ns] 2. 5 5. 5 10. 2 39. 8 2. 8 6. 2 12. 3 46. 5 2. 4 4. 6 9. 7 41. 9 } } } Bernd Lewandowski - Ruhr-Universität Bochum - SCINT 2003 5 samples on rising edge 3 samples on rising edge 10 samples on rising edge 29

BGO • BGO has sufficient light yield • Timing can be handled by adequate electronics We will perform further investigations with BGO as an option for the Panda Emc 11. 9. 2003 Bernd Lewandowski - Ruhr-Universität Bochum - SCINT 2003 30

Summary & Outlook R&D tasks • • • Improvement of PWO light yield Detailed time resolution studies for BGO Tests of APD readout and radiation damage – Planned this year: testbeam @ KVI, MAMI • Development of large area APDs (100 mm 2) by Hamatsu • Tests of other Photosensors 11. 9. 2003 Bernd Lewandowski - Ruhr-Universität Bochum - SCINT 2003 31

Panda Collaboration At present a group of 150 physicists from 40 institutions of 9 Countries. Austria - Germany – Italy – Netherlands – Poland – Russia – Sweden – U. K. – U. S. Bochum, Bonn, Catania, Cracow, Dresden, Dubna I + II, Edinburg, Erlangen, Ferrara, Frascati, Genova, Giessen, Glasgow, KVI Groningen, FZ Jülich I + II, Los Alamos, Mainz, Milano, TU München, Münster, Northwestern, BINP Novosibirsk, Pavia, Silesia, Stockolm, Torino I + II, Torino Politecnico, Trieste, TSL Uppsala, Tübingen, Uppsala, SINS Warsaw, AAS Wien Spokesperson: Ulrich Wiedner - Uppsala Deputy: Paola Gianotti - LNF 11. 9. 2003 http: //www. gsi. de/hesr/panda Bernd Lewandowski - Ruhr-Universität Bochum - SCINT 2003 32

Appendix 11. 9. 2003 Bernd Lewandowski - Ruhr-Universität Bochum - SCINT 2003 33

Target An internal cluster-jet/pellet target is under study: 1016 atoms/cm 2 for D=20 -40 mm Pellet target layout Cluster-jet target layout 11. 9. 2003 Bernd Lewandowski - Ruhr-Universität Bochum - SCINT 2003 34

Vertexing: Micro Vertex Detector 7. 2 mio. barrel pixels 50 x 300 μm pellet/cluster pipe beam pipe 2 mio. forward pixels 100 x 150 μm Readout: ASICs (ATLAS/CMS) 0. 37% X 0 or pixel one side – readout other side (TESLA) 11. 9. 2003 Bernd Lewandowski - Ruhr-Universität Bochum - SCINT 2003 35

Tracking: Straw Tube Tracker Number of double layers Skew angle of dbl layers 1 and 15 Skew angle of dbl layers 2 -14 15 0 o 2 o-3 o Straw tube wall thickness Wire thickness Gas Length Diameter of tubes in double layers 1 -5, 6 -10, and 11 -15 Number of straw tubes 26 mm 20 mm 90%He 10%C 4 H 10 150 cm 4 mm 6 mm 8734 Transverse resolution sx, y Longitudinal resolution sz 150 mm 11. 9. 2003 Bernd Lewandowski - Ruhr-Universität Bochum - SCINT 2003 36

Tracking: Forward MDC • 6 layers of sense wires in • 3 double layers (y, u, v) • not stretched radially (mass) • realized at HADES – high counting rates – position resolution 70μm HADES@GSI 11. 9. 2003 Bernd Lewandowski - Ruhr-Universität Bochum - SCINT 2003 37

PID: DIRC (Cherenkov) Ba. Bar@SLAC less space than aero gel � costs of calorimeter no problems with field 11. 9. 2003 Bernd Lewandowski - Ruhr-Universität Bochum - SCINT 2003 38

PID: Forward RICH Multi pad gas Detector Mismatch photons �� Cs. I photon conversion LHCb Aerogel n=1. 02 proximity focusing mirrors 11. 9. 2003 Bernd Lewandowski - Ruhr-Universität Bochum - SCINT 2003 39

APD Hamamatsu S 8664 -55 5 mm 11. 9. 2003 Bernd Lewandowski - Ruhr-Universität Bochum - SCINT 2003 40

Ce. F 3 high energy photondetection counts low energy protondetection @MZ protonenergy / Me. V 85 Me. V p + C @ KVI good resolutionfor protonsdue to: • high lightoutput • localizedenergy deposition generalapplicabilityproven ! 11. 9. 2003 R. Novotnyet al. , II. Phys. Inst. GI in collaborationwith Korth-Kristalle Gmb. H limitedresolutionfor photonsdue to: • imperfectionof crystals • insufficientsize in spite of high luminescence yield Bernd Lewandowski - Ruhr-Universität Bochum - SCINT 2003 41

Ce. F 3 • Ce. F 3 needs further R&D to improve resolution for photons • Rel. long X 0 compact design not possible (compared to PWO) • Constraints from target may limit the available space for the EMC Ce. F 3 is not an option for the barrel part 11. 9. 2003 Bernd Lewandowski - Ruhr-Universität Bochum - SCINT 2003 42

BGO: event rates • Max. occupancy of one crystal due to bkgr simulations: 2% · 107 events/s = 2· 105 s-1 • Use digital tail cancelation in the feature extraction • conservative scaling of the rise time – Cs. I: 100 ns / 940 ns – BGO: 12 ns / 200 ns • Rate we can handle: ( 2·trise· 10 )-1 = 2. 5· 105 events/s 11. 9. 2003 Bernd Lewandowski - Ruhr-Universität Bochum - SCINT 2003 43

Why Antiprotons? • high resolution spectroscopy with p-beams in formation experiments: – E Ebeam • high yields in pp of gluonic excitations – glueballs, hybrids • event tagging by pair wise associated production, – (particle, anti-particle) e. g. pp bar • large √s at low momentum transfer – important for in-medium "implantation" of hadrons: – study of in-medium effects 11. 9. 2003 Bernd Lewandowski - Ruhr-Universität Bochum - SCINT 2003 44

Timeline • since 1996 Discussion about GSI future International workshops, reviews, accelerator R&D • May 1999 Letter of Intend for an antiproton facility (40 authors) Studies for detector concept • Jan. 2001 Detector simulation with GEANT 4 • Nov. 2001 Conceptual Design Report of an „International Accelerator Facility for Beams of Ions and Antiprotons” • Nov. 2001 Review by an international review committee of the „Deutscher Wissenschaftsrat“ • April 2002 International p-Workshop at GSI • July 2002 Positive Votum by the „Deutscher Wissenschaftsrat“ • Feb. 5, 2003 Positive Decision by the „bmb+f” 11. 9. 2003 Bernd Lewandowski - Ruhr-Universität Bochum - SCINT 2003 45

Resonance Scan Resonance Cross Section Measured Rate Beam Profile ECM small and well controlled beam momentum spread p/p is extremely important 11. 9. 2003 Bernd Lewandowski - Ruhr-Universität Bochum - SCINT 2003 46