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Electromagnetic Calorimeter for HADES at SIS100

Pavel Tlustý , NPI Řež. Electromagnetic Calorimeter for HADES at SIS100. Involved groups: Jag. University Krakow INR Moscow NPI Rez …… ?. Motivation Plans Current s tatus Tests Outlook. May 8, 2009. HADES Collaboration Meeting, Sesimbra, May 5-10, 2009. Motivation.

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Electromagnetic Calorimeter for HADES at SIS100

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  1. Pavel Tlustý, NPI Řež Electromagnetic Calorimeter for HADES at SIS100 • Involved groups: • Jag. University Krakow • INR Moscow • NPI Rez • …… ? • Motivation • Plans • Current status • Tests • Outlook May 8, 2009 HADES Collaboration Meeting, Sesimbra, May 5-10, 2009

  2. Motivation - measurements of the respective pº and ηmeson two gamma decay yields together with the dielectron data for the knowledge of dielectron coctail and normalization at incident heavy ion energies 2-8 AGeV - better electron/pion suppression for large momenta (p>400 MeV/c) as compared to the present situation (at lower momenta the electron/hadron identification will be provided by the RICH and RPC)

  3. Motivation Eur. Phys. J. C 4, 231-247 (1998) Eur. Phys. J. C 4, 249-257 (1998)

  4. HADES & EMC Side View START ElectroMagnetic Calorimeter (EMC) will replace theHADES Pre-Shower detector (18º< Θ< 45º). EMC RPC The total area required for a HADES calorimeter amounts to about 8m2 !!

  5. Detector modules Our proposal is to use lead glass modules from OPAL end cap calorimeter. ~ 900 modules needed, at present (April 2009) 1080 modules moved to GSI. Moduledimensions: 42 x 9 x 9 cm Lead glass properties: - type: CEREN 25 - chemical composition (SiO2 -39%,PbO – 55%, K2 - 2%, Na20 – 3%) - density: 4.o6 g/cm3 - radiation length (X0): 2.51 cm - refractive index: 1.708 (at 400 nm) Nucl. Instr. Meth. A290, 76 (1990) Energy resolution ~ 5%/sqrt(E), E in GeV

  6. Signal Read-out PMT - EMI 9903KB (1.5'') from MIRAC (WA98 hadron calorimeter) ~720 PMT's diameter – 38 mm (1.5'') diameter of photocathode – 34 mm Front-end readout – ADC ADD-ON (Shower)+ TRB

  7. Design • Number of modules 150x6=900 • Mass of one module of lead-glass14 kg • Total mass of cal. 12600 kg E. Lisowski, TU Krakow

  8. Tests Source – cosmics muons: energy ≈ 2 GeV, energy deposit in module ≈ 200 MeV, Cerenkov light output corresponds to ≈ 400 MeV electrons count rate ≈ 30 particles / hour Measurement of pulse height (ADC) spectra – check of energy resolution various PMTs, configuration with/without lightguide Oct. 2008 - test of various PMTs Apr. 2009 - test of lightguide

  9. Cosmic test setup lead glass module trigger detectors count rate: ~ 30 particles / hour

  10. Cosmic test – various PMTs Nph.el. ≈ 1/ σ2 EMI 9903KB σ/Nmean= 10.6 % or Nph.el > 88

  11. Assembling of lead glass modules with lightguide and PMT OPAL leadglassmodule 420 mm length plexiglasslightguide PMT HV divider plexiglaslightguide PMT

  12. Cosmic test – PMT pulses without lightguide with lightguide A≈ 500 mV cosmic muons correspond to ≈400 MeV e- Light collection with lightguide in average 3 times worse than direct PMT-glass connection New lightguide from lead glass to be tested, better shape?

  13. Cosmic test – ADC spectra without lightguide with lightguide σ/Nmean≈ 40% without lightguide (Oct 2008) σ/Nmean= 10.6 % or Nph.el > 88 Nph.el. ≈ 1/ σ2

  14. Cosmic muon ADC spectra our data Fermilab E760 Central Calorimeter module length 50 cm σ/Nmean= 10.6 % σ/Nmean≈ 7 % OPAL e- 1 GeV Np.e.≈ 1800 s ≈ 5% E760 e- 1 GeV Np.e.≈ 4250 s ≈ 5% E760 m≈ 2 GeV Np.e.≈ 2082 s ≈ 7% http://www.e835.to.infn.it/people/gollwitz/thesis/ K. Gollwitzer, PhD thesis, University of California at Irvine, 1993

  15. Tests - plans May – June - Cosmic muons, test of lightguide June – July - Electron beam @ MAMI response to 100 – 2000 MeV electrons up to 8 modules, various configurations

  16. PMT Tests PMT EMI 9903KB (1.5'') ~720 PMTs available 500 PMTs tested HV dependence of PMT response: PMT alone at HV=1500 and 1700 V, PMT with a gamma-source 22Na at HV=1200, 1500, and 1700 V; The results for HV=1500 V: <500 mV 79 pieces of PMTs 16% 500 mV < U < 1500 mV 120 pieces of PMTs 1500 mV < U < 2700 mV 191 pieces of PMTs >2700 mV 110 pieces of PMTs

  17. Summary • motivation: improved dilepton spectroscopy by HADES  lepton and photon pairs at the same time • current status  detector modules available  PMT – 70% available, 70% of them tested  tests with cosmics going on  simulation in progress - see next talk  mechanical construction designed • plans • tests on electron beam (and cosmics) • fixing the detector module setup • building one sector • building full calorimeter

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