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

2. Condensates and Spectrum 2008/12/06 Nagoya, K. Ozawa 2 We can link condensates and vector meson spectrum. q q Vacuum QCD sum rule Average of Imaginary part of ( 2 ) vector meson spectral function Average of Imaginary part of ( 2 ) vector meson spectral function T.Hatsuda and S. Lee, PRC 46 (1992) R34 Prediction Spectrum mVmV The relation is established robustly. Assume vector meson spectral function Experimental results Model Calculation Mass Shift: m  = m 0 (1 -   /  0 ) for  = 0.03 Average of measured spectra p Calculate amout of quark condensate using QCD sum rule. Next Experiment Need large statics

3. 2008/12/06 Nagoya, K. Ozawa 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!! 3

4. 2008/12/06 Nagoya, K. Ozawa Major components GEM Tracker Gas Cherenkov for e-ID Magnet modification EM Calorimeter Prototype is made and being tested 4 GEM Tracker Gas Cherenkov for e-ID

5. GEM TRACKER 2008/12/06 Nagoya, K. Ozawa 5

6. 2008/12/06 Nagoya, K. Ozawa Required Resolution Momentum and mass resolution are evaluated based on KEK knowledge. –Position resolution: 300 m for E325 50 m, 100 m, 200 m, and 300 m for J-PARC –Multiple scattering Radiation length of detectors are increased for GEM foils –Larger acceptance for 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. Momentum Resolution [GeV/c] mass res. v.s. position res. [m] J-PARC KEK 300 m 200 m 100 m 50 m 6

7. 2008/12/06 Nagoya, K. Ozawa GEM Tracker To cover large acceptance and cope with high counting rate, 3 layers of GEM trackers are used. 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 Collaboration with KEK COMPASS detector (NIM A535, 314) Rate issue: 5 kHz/mm 2 is expected at J-PARC with 700 m pitch x 100mm height COMPASS detector is working Up to 25 kHz/mm 2 (400 m pitch) GEM detector will work 7 Kapton (d=50μm) Cupper (d=5μm)

8. 2008/12/06 Nagoya, K. Ozawa GEM and Read out Collaboration with KEK 2-D strip readout configuration NIM A425(1999)254 8 GEM foils made in Japan (SciEnergy) Ar-CO 2 Japanese CERN Relative Gain with 3 GEM foils

9. 2008/12/06 Nagoya, K. Ozawa 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 m pitch Copy of KEK ’ s 9

10. 2008/12/06 Nagoya, K. Ozawa Signals We can see signals from both sides. Signal from bottom surface is distorted. Already known problem by KEK group. Strips on top surfaceStrips on bottom surface TOP Bottom Bottom2 Bottom1 TOP1 TOP2 10

11. 2008/12/06 Nagoya, K. Ozawa Sum Sum of 3 strips looks reasonable distribution. Check with X-ray Strip1Strip2Strip3 Fe-55 X-ray Source 11 Position distribution is almost reasonable. Position Beam test is done. Results of resolution will be appeared soon. Beam test is done. Results of resolution will be appeared soon.

12. GAS CHERENKOV 2008/12/06 Nagoya, K. Ozawa 12

13. 2008/12/06 Nagoya, K. Ozawa Used @ KEK-PS E325 Gas Cherenkov Detector Electron Identification using gas cherenkov Used for low momentum electron Photo Cathode + GEM for amplification No Mirror –Mirror and PMT, traditionally Difficulty for Large acceptance Requirement of large acceptance at J-PARC E16 experiment CSI photo-cathod –UV sensitive (6 eV, 200nm) –High quantum efficiency 13

14. 2008/12/06 Nagoya, K. Ozawa 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. Existing data by Weizmann Inst. 14

15. 2008/12/06 Nagoya, K. Ozawa Old beam test @ Hiroshima Operation –Pure CF 4 (cosθ c =0.035) –CsI GEM 150V –Other GEM 490V (~10 4 ) –Water ~ 1ppm 1*1cm Readout Pad 5x5 used Electrons from ionization Light Shield Inverse field Light shade ON –dE/dx (1mm) Light shade OFF –dE/dx (1mm) + Light 15

16. 2008/12/06 Nagoya, K. Ozawa Results Inverse field, light shield on, dE/dx (1mm) Only Inverse field, light shield off, dE/dx (1mm) + Light 16 0204040 60608080 [Charge] Arbitrary Unit 7 fc Clear signal for energy loss 10 fc Small difference, statistically It can be Cherenkov origin. New R&D is underway at RIKEN. Results will be appeared soon. New R&D is underway at RIKEN. Results will be appeared soon.

17. 2008/12/06 Nagoya, K. Ozawa 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. 17

18. Back up

19. 2008/12/06 Nagoya, K. Ozawa Issue: counting Rate Interaction rate is 10 6 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. 19

20. 2008/12/06 Nagoya, K. Ozawa 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 10 5 Hz/mm 2 –I like flexibility of configuration –Good characteristics of signal Signal is generated by electron Not by ion No ion tail and pole cancellation electronics I took these ideas and figures from F. Sauli ’ s presentation at XIV GIORNATE DI STUDIO SUI RIVELATORI Villa Gualino 10-13 Febbraio 2004 GEM MWPC 10 4 10 5 20

21. What can be achieved? 2008/12/06 Nagoya, K. Ozawa 21 Pb  Modified  [GeV/c 2 ]  from Proton Invariant mass in medium         p dep. High resolution calculate quark condensate

22. 2008/12/06 Nagoya, K. Ozawa Pictures from PHENIX signal electron partner positron needed for rejection In PHENIX IR Globe box Evaporate machine 22

23. 2008/12/06 Nagoya, K. Ozawa CSI photo cathode Transmissive By Weitzman Transmissive type is used –Suitable with GEM –Relatively high quantum efficiency –Low photon feedback CSI Q. E. ５１０１５ [eV] CsI Au Ni Cu Kapton Cu Vapor deposition on GEM By Hamamatsu 23

24. 2008/12/06 Nagoya, K. Ozawa In reality 24