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Detector R&D: J-PARC-E16

Detector R&D: J-PARC-E16. K. Ozawa (Univ. of Tokyo) for the E16 collaboration. Condensates and Spectrum. We can link condensates and vector meson spectrum. T.Hatsuda and S. Lee, PRC 46 (1992) R34. The relation is establish ed robustly. Average of Imaginary part of P ( w 2 )

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Detector R&D: J-PARC-E16

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  1. Detector R&D: J-PARC-E16 K. Ozawa (Univ. of Tokyo) for the E16 collaboration

  2. Condensates and Spectrum We can link condensates and vector meson spectrum. T.Hatsuda and S. Lee, PRC 46 (1992) R34 The relation is establishedrobustly. • Average of Imaginary part of P(w2) • vector meson spectral function q Vacuum Vacuum QCD sum rule p q Next Experiment Model Calculation Prediction Experimental results Assume Average of measured spectra vector meson spectral function Calculate amout of quark condensate using QCD sum rule. Mass Shift: mf=m0 (1 -  /0) for  = 0.03 mV Spectrum Need large statics Nagoya, K. Ozawa

  3. New Spectrometer 5 times larger acceptance for pairs E16 Spectrometer KEK Spectrometer Cope with 10 times larger beam intensity!! 2 times larger cross section Total, 100 times higher statistics!! Nagoya, K. Ozawa

  4. Major components Prototype is made and being tested Magnetmodification Gas Cherenkov for e-ID GEM Tracker GEM Tracker Gas Cherenkov for e-ID EM Calorimeter Nagoya, K. Ozawa

  5. GEM Tracker Nagoya, K. Ozawa

  6. Required Resolution KEK 300 mm • Momentum and mass resolution are evaluated based on KEK knowledge. • Position resolution: • 300 mm for E325 • 50 mm, 100 mm, 200 mm, and 300 mm for J-PARC • Multiple scattering • Radiation length of detectors are increased for GEM foils • Larger acceptance for J-PARC 200 mm 100 mm 50 mm [GeV/c] Momentum Resolution J-PARC • To have the improved mass resolution, • Target Resolution is 100 mm • It can be achieved 0.7 mm pitch and strip charge information. KEK Nagoya, K. Ozawa [mm] mass res. v.s. position res.

  7. Kapton (d=50μm) Cupper (d=5μm) GEM Tracker Collaboration with KEK • To cover large acceptance and cope with high counting rate, 3 layers of GEM trackers areused. • Similar to COMPASS detector • Use 3 layers in magnetic field • Extend to large acceptance • Challenge : • Long term stability • Mechanical support with low radiation length • Readout • Rate issue: • 5 kHz/mm2 is expected at J-PARC • with 700 mm pitch x 100mm height • COMPASS detector is working • Up to 25 kHz/mm2 (400 mm pitch) • GEM detector will work COMPASS detector (NIM A535, 314) Nagoya, K. Ozawa

  8. Ar-CO2 GEM and Read out Collaboration with KEK • GEM foils made in Japan (SciEnergy) Relative Gain with 3 GEM foils • 2-D strip readout configuration Japanese CERN NIM A425(1999)254 Nagoya, K. Ozawa

  9. R&D @ Tokyo • Purpose: • Develop a GEM tracker • Evaluate specifications • Position resolution • Efficiency • Rate dependence • Current Configuration: • 3 GEM foils • p-10 gas • 2-D strip • Both side • 0.8 mm pitch • Copy of KEK’s Nagoya, K. Ozawa

  10. Signals TOP • We can see signals from both sides. • Signal from bottom surface is distorted. • Already known problem by KEK group. Bottom TOP1 Bottom1 Bottom2 TOP2 Strips on top surface Strips on bottom surface Nagoya, K. Ozawa

  11. Sum Position Position distribution is almost reasonable. Sum of 3 strips looks reasonable distribution. Check with X-ray Strip1 Strip2 Strip3 Fe-55 X-ray Source Beam test is done. Results of resolution will be appeared soon. Nagoya, K. Ozawa

  12. Gas cherenkov Nagoya, K. Ozawa

  13. Gas Cherenkov Detector • Mirror and PMT, traditionally • Difficulty for Large acceptance • Electron Identification using gas cherenkov • Used for low momentum electron • Requirement of large acceptance • at J-PARC E16 experiment Photo Cathode + GEM for amplification No Mirror Used @ KEK-PS E325 • CSI photo-cathod • UV sensitive (6 eV, 200nm) • High quantum efficiency Nagoya, K. Ozawa

  14. Existing data by Weizmann Inst. Measurements of Q.E. • We got a consistent result with existing data. • Based on this measurements, the number of photo-electron with 84 cm long radiator is estimated as 65. Nagoya, K. Ozawa

  15. Old beam test @ Hiroshima 1*1cm Readout Pad 5x5 used • Operation • Pure CF4 (cosθc=0.035) • CsI GEM • 150V • Other GEM • 490V (~104) • Water ~ 1ppm Light Shield • Inverse field • Light shade ON • dE/dx (1mm) • Light shade OFF • dE/dx (1mm)+ Light Electrons from ionization Nagoya, K. Ozawa

  16. Results Inverse field, light shield on, dE/dx (1mm) Only Inverse field, light shield off, dE/dx (1mm) + Light Clear signal for energy loss 7 fc Arbitrary Unit 10 fc Small difference, statistically It can be Cherenkov origin. New R&D is underway at RIKEN. Results will be appeared soon. [Charge] 60 80 Nagoya, K. Ozawa 0 20 40

  17. Summary • For J-PARC E16, a GEM based spectrometer is proposed to cope with high interaction rate and have large acceptance. • R&D has started for J-PARC at Tokyo and RIKEN. GEM tracker with 2-D strip read out is being developed. First brief result of R&D is appeared. • Cherenkov counter using CSI photocathode and GEM readout is the essential part to extend the acceptance. R&D is on-going. Nagoya, K. Ozawa

  18. Back up

  19. Issue: counting Rate • Interaction rate is 106 Hz at KEK (x10 @J-PARC) • However, beam halo can not be ignored • For example, actual condition at KEK is following. • 350 kHz at the most forward cell of Drift Chamber • At radius of 200 mm and the horizontal angle of 6° • 3.5mm width and 220 mm height • Mostly from beam halo • Extrapolate to J-PARC • 10 times higher beam intensity • shorter beam-extraction duration • 3.5 MHz is expected. • 10 times finer segments are required • 0.7 mm pitch x 100mm height • That’s the main issue for spectrometer design. • We have to develop the detector which cope with 10 times larger rate. Nagoya, K. Ozawa

  20. Detectors in high counting • MWPC limitation • Wire spacing: 1~2 mm • Gain dropping @ high rate • Micro strip gas chamber • Discharge problem • Micromegas • Another candidate • GEM • Flat gain up to 105 Hz/mm2 • I like flexibility of configuration • Good characteristics of signal • Signal is generated by electron • Not by ion • No ion tail and pole cancellation electronics MWPC 104 105 GEM I took these ideas and figures from F. Sauli’s presentation at XIV GIORNATE DI STUDIO SUI RIVELATORI Villa Gualino 10-13 Febbraio 2004 Nagoya, K. Ozawa

  21. Pb f Modified f [GeV/c2] Invariant mass in medium What can be achieved? f f f f f f f f f from Proton p dep. High resolution calculate quark condensate Nagoya, K. Ozawa

  22. signal electron partner positron needed for rejection Pictures from PHENIX In PHENIX IR Globe box Evaporate machine Nagoya, K. Ozawa

  23. CsI Au Ni Cu Kapton Cu CSI photo cathode • Transmissive type is used • Suitable with GEM • Relatively high quantum efficiency • Low photon feedback Transmissive By Weitzman • Vapor deposition on GEM • By Hamamatsu ５ １０ １５ [eV] CSI Q. E. Nagoya, K. Ozawa

  24. In reality Nagoya, K. Ozawa

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