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MEG 最初の一年、その展望

MEG 最初の一年、その展望. 東京大学素粒子物理国際研究センター 三原　智. Contents. Introduction MEG Detector Sensitivity and background Our schedule Summary. Introduction. n e. n m. e. μ. μ. e. W. Br( m e g ) ∝ (sin q m e (m m 2 -m e 2 )/m 2 SUSY ) 2. ~. ~. ~. ~. g. g. μ → e γ.

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MEG 最初の一年、その展望

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  1. MEG最初の一年、その展望 東京大学素粒子物理国際研究センター 三原　智 Satoshi MIHARA, ICEPP Univ. of Tokyo, JSPS meeting in Matsuyama

  2. Contents • Introduction • MEG Detector • Sensitivity and background • Our schedule • Summary Satoshi MIHARA, ICEPP Univ. of Tokyo, JSPS meeting in Matsuyama

  3. Introduction Satoshi MIHARA, ICEPP Univ. of Tokyo, JSPS meeting in Matsuyama

  4. ne nm e μ μ e W Br(meg) ∝(sinqme(mm2-me2)/m2SUSY)2 ~ ~ ~ ~ g g μ→eγ • Lepton Flavor Violation (LFV) is strictly forbidden in SM • Neutrino oscillation • LF is not conserved • Contribute ∝ (mn/mW)4 • Supersymmetry • Off-diagonal terms in the slepton mass matrix Just below the current limit Br(μ→eγ) = 1.2 x 10-11 (MEGA, PRL 83(1999)83) Satoshi MIHARA, ICEPP Univ. of Tokyo, JSPS meeting in Matsuyama

  5. Other LFV search experiments • tmg, eg • KEK, BELLE • SLAC, BABAR • m-e conversion • J-PARC, PRISM project, PRIME Satoshi MIHARA, ICEPP Univ. of Tokyo, JSPS meeting in Matsuyama

  6. MEG  eg decay search experiment at Paul Scherrer Institut Japan, Italy, Switzerland, Russia, USA Satoshi MIHARA, ICEPP Univ. of Tokyo, JSPS meeting in Matsuyama

  7. Signal Eg = mm/2 = 52.8MeV Ee = mm/2 = 52.8MeV q = 180o Time coincidence Background Radiative m decay Accidental overlap g m e g Signal and Background g n m n e n n m ? e Satoshi MIHARA, ICEPP Univ. of Tokyo, JSPS meeting in Matsuyama

  8. Essentials • Intense muon beam • DC beam is better to reduce accidental pile-up events • Gamma Detector • Good resolutions • Capability of identifying pile-up events • Positron Detector • Good resolutions • Low amount of material • Blind to low energy positrons  Liquid Xenon Detector  COBRA spectrometer Satoshi MIHARA, ICEPP Univ. of Tokyo, JSPS meeting in Matsuyama

  9. PSI Proton Cyclotron Target unit Target flask Proton energy: 590MeV Nominal operation current: 1.8mA. Max > 2.0mA possible. MEG Satoshi MIHARA, ICEPP Univ. of Tokyo, JSPS meeting in Matsuyama

  10. Liquid xenon photon detector COBRA spectrometer – Magnet, DC, TC All detector waveforms are recorded. MEG Detector Satoshi MIHARA, ICEPP Univ. of Tokyo, JSPS meeting in Matsuyama

  11. Trip I Trip II COBRA ASC Sep Y X BTS Beam Line Beam Transport Solenoid Target separator • Length 10.4 m • Solid angle 150 msr • Momentum acceptance (FWHM) 10 % • Momentum resolution (FWHM) 2 % 森田裕一　“MEG実験におけるビームチューニング”　29日午後 Satoshi MIHARA, ICEPP Univ. of Tokyo, JSPS meeting in Matsuyama

  12. Beam Line Commissioning • 2005 mid July – end August • Beam Transport Solenoid (BTS) Commissioning • Bfield mapping • Phase space measurements up to end BTS • 2005 beg November – end December • Commissioning BTS with Cryo-plant and Control system • BTS automated operation • Phase Space measurements inside COBRA • Pill scinti + APD on 3-D measuring machine • End-caps and insertion system • Complex design He/Vacuum/N2/Air interface • Materials minimized Al & CH2/EVAL (background) DS US Calibration target installation Satoshi MIHARA, ICEPP Univ. of Tokyo, JSPS meeting in Matsuyama

  13. Target System • Various solutions under study • Target material • Rohacell form/CH2 combination • Complete Rohacell • CH2 or polystyrene Target + wire frame DC Structure Insertion Bellows Satoshi MIHARA, ICEPP Univ. of Tokyo, JSPS meeting in Matsuyama

  14. COBRA Magnet • 360A, 1.27T • 0.197X0 around the center Compensation coil (NC) Inner/Outer end coil (SC) Gradient coil (SC) Central coil (SC) Satoshi MIHARA, ICEPP Univ. of Tokyo, JSPS meeting in Matsuyama

  15. COBRA Magnet • Cooling by using two GM-type refrigerators • No need of helium for operation • Compensation coil to reduce field strength around the xenon detector • Field measurement has been completed recently Design field Measured field around the xenon detector Satoshi MIHARA, ICEPP Univ. of Tokyo, JSPS meeting in Matsuyama

  16. Liquid Xenon Detector • 800~900 liquid xenon • 846 PMTs immersed in the liquid • No segmentation • Why Liquid Xe ? • Good resolutions • Large light output yield • Wph(1MeV e) = 22.4eV • Pile-up event rejection • Fast response and short decay time • ts = 4.2nsec, tT=45nsec (for electron, no E) • 西村康宏　“MEG実験用光電子増倍管の液体キセノン中におけるLEDを用いた利得解析と現状”　27日午後 Satoshi MIHARA, ICEPP Univ. of Tokyo, JSPS meeting in Matsuyama

  17. Depth Reconstruction • Broadness of light distribution at the entrance side waveform shallow deep Satoshi MIHARA, ICEPP Univ. of Tokyo, JSPS meeting in Matsuyama

  18. No zener with zener PMT test in LXe • All PMTs were tested in LXe before installing to the detector • Pisa LXe PMT test facility • Xenon Detector Large Prototype • QE, Gain, response linearity • All information is stored in a database for future use. Bad Satoshi MIHARA, ICEPP Univ. of Tokyo, JSPS meeting in Matsuyama

  19. Construction Status • Cryostat Construction in progress in Italy • Delivery in June • PMT installation and setup after that • Ready in September Satoshi MIHARA, ICEPP Univ. of Tokyo, JSPS meeting in Matsuyama

  20. DC • Position resolutions (~300mm) for both r and z. • Vernier pad readout for z measurement • Low amount of material • Need very precise pressure control ~1Pa Satoshi MIHARA, ICEPP Univ. of Tokyo, JSPS meeting in Matsuyama

  21. TC APD F.E. Board APD APD Cooled Support TC Final Design Scintillating Fibers (Phi Counter) PM ladder Board & cabling Main Support BC404-Scintillator slab • A PLASTIC SUPPORT STRUCTURE ARRANGES THE SCINTILLATOR BARS AS REQUESTED • THE BARS ARE GLUED ONTO THE SUPPORT • INTERFACE ELEMENTS ARE GLUED ONTO THE BARS AND SUPPORT THE FIBRES • FIBRES ARE GLUED AS WELL • TEMPORARY ALUMINIUM BEAMS ARE USED TO HANDLE THE DETECTOR DURING INSTALLATION • PTFE SLIDERS WILL ENSURE A SMOOTH MOTION ALONG THE RAILS Scintillator Housing PM-Scintillator Coupling Satoshi MIHARA, ICEPP Univ. of Tokyo, JSPS meeting in Matsuyama

  22. TC Assembly • PMT test completed • Assembly test started Satoshi MIHARA, ICEPP Univ. of Tokyo, JSPS meeting in Matsuyama

  23. Electronics Satoshi MIHARA, ICEPP Univ. of Tokyo, JSPS meeting in Matsuyama

  24. 2 boards LXe front face (216 PMTs) 2 x48 5+5+2 boards LXe lateral faces back (216 PMTs) 4 in 1 lat. (144x2 PMTs) 4 in 1 up/down (54x2 PMTs) 4 in 1 . . . 14 boards . . . 1 board Type2 Type2 Type2 Type2 Type2 14x 48 9 x 48 2 x48 Type1 Type1 Type1 Type1 Type1 Type1 Type1 Type1 Type1 Type1 Type1 Type1 1 board Timing counters curved (640 APDs) 8 in 1 u/d stream (30x2 PMTs) 4 4 4 4 4 16 16 16 16 16 16 1 x48 9 boards 1 board . . . 2 boards 9x 48 Drift chambers 16+16 channels 2x 48 Auxiliary devices 16 channels 1 x48 Trigger Tree Satoshi MIHARA, ICEPP Univ. of Tokyo, JSPS meeting in Matsuyama

  25. Trigger Electronics • PCB production finished • Currently board mounting in progress • Ready to install in June Type 2 Type 1 Satoshi MIHARA, ICEPP Univ. of Tokyo, JSPS meeting in Matsuyama

  26. DAQ/Waveform Digitizer R. Paoletti, N. Turini, R. Pegna MAGIC collaboration PSI GVME Board FPGA with 4 Power-PC DRS USB Satoshi MIHARA, ICEPP Univ. of Tokyo, JSPS meeting in Matsuyama

  27. DRS – Domino Ring Sampler Domino Ring Sampler Satoshi MIHARA, ICEPP Univ. of Tokyo, JSPS meeting in Matsuyama

  28. Waveform Analysis • Q,T evaluation from waveforms • Pile-up rejection • Waveform fitting is very CPU time consuming Peak search method DT=50ns. DT=15ns simulation simulation Differential method • Constant fraction • Fraction:0.3, delay 10nsec simulation simulation • 内山雄祐　“MEG実験用液体キセノン検出器の波形解析による性能評価”　27日午後 11MeV + 42MeV Satoshi MIHARA, ICEPP Univ. of Tokyo, JSPS meeting in Matsuyama

  29. Background and Sensitivity 4E7sec 1 100psec δθeγ= 14mrad # of Background events, 2 years RUN Energy deposit/ 52.8MeV PILE UP EVENTS RD+RD dominant Muon stopping rate [/sec] Satoshi MIHARA, ICEPP Univ. of Tokyo, JSPS meeting in Matsuyama

  30. How Far Can We Go? • Expected sensitivity at 90% C.L. YEAR 2006 1 MONTH BEAMTIME BEAMTIME=4E7 sec 2 year Very Preliminary muon beam intensity (/sec) muon beam intensity (/sec) Satoshi MIHARA, ICEPP Univ. of Tokyo, JSPS meeting in Matsuyama

  31. Schedule • MEG beam time; Apr-Jun, Aug-Dec • DC/TC run with beam; Sep- • LXe • Setup; -Sep~Oct, Calibration run; ~Nov – • Ready in Nov • DAQ/Trigger; Ready in Jun • Ready to start DAQ; ~mid Nov Satoshi MIHARA, ICEPP Univ. of Tokyo, JSPS meeting in Matsuyama

  32. Summary • MEG starts in 2006 • Detectors are getting ready • Analysis/online softwares also • For further information, visit http://meg.icepp.s.u-tokyo.ac.jp • 澤田龍　“汎用データ解析ソフトウェア生成ツールROME&ARGUS”30日午後 Satoshi MIHARA, ICEPP Univ. of Tokyo, JSPS meeting in Matsuyama

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