MEG Summary T. Mori for MEG Collaboration February 9, 2005

The MEG Collaboration Spokespersons: T.Mori, A.Baldini Technical Coordinator: S.Ritt Detectors: Beam line: PSI P.-R.Kettle COBRA: KEK/Tokyo W.Ootani Drift Chamber: PSI J.Egger Timing Counter: Genova/Pavia/Roma G. Cecchet Photon Detector: Tokyo/Pisa/KEK S.Mihara Trigger: Pisa M.Grassi DAQ/Elec.: PSI S.Ritt Offline: C.Gatto/S.Yamada/F.Cei

Highlights in developments sine July 2004 Beam line Separator, BTS in construction COBRA Fringing field problem ~solved LXe Beam test w/ new PMTs, waveform digitizers, and wire alpha sources Detector cryostat in construction

Absolute time of LXe normal gain high gain 110 psec 103 psec 55 MeV LYSO target Intrinsic from LR analysis depth

Background and Sensitivity Jan 2004 Jan 2005 Gamma Energy (%) 4.5-5.0* e+ Timing (nsec) 0.1* Gamma Timing <0.23* ~0.15** Gamma Position (mm) 4.5-9.0* Gamma acceptance >0.4* Muon rate (108/sec) 0.2-0.3 0.25-0.35 Running Time (107sec) 4.0 Accidental Rate (10-14) 2.3-3.5 1.9-3.0 # Accidental Events 0.6 0.6 90% CL Limit (10-13) 1.2-1.7 0.9-1.4 * Measured **w/ new PMTs More detailed calculation necessary

Schedule

Changes (~delays) in schedule Beam line BTS construction LXe Detector cryostat construction PMT delivery new problem arising -- solution foreseen DC Troubles with cathode foil production

Noise from Zener diode

PMT testing + calibration 2005 2006 J F M A S O N D Beam Time Shutdown MEG COBRA Tests P Field Map Beam Line BTS Test Commiss. Part 2 Tgt Full Test Drift Chamber Proto Inst Full Installation Timing Counter BG TstInst LPT PMT testing + calibration Calorimeter Cryogenics Assembly + Trigger DAQ DC Electr.

Manpower

Mostly in healthy situation except: beam line + target Monte Carlo

Budget

We now have enough money for PMTs! a new budget for construction in Japan ~400 PMTs additional budget for ~110 PMTs in Italy Then new problems arising… LXe for last 300liters electronics LXe calibration equipment proton beam? PSI

PREVIOUS   e g EXPERIMENT 1982 !!

NOW: GLAST SPACE EXPERIMENT CRYSTAL CALORIMETER CALIBRATION 180 cm target-pipe It is the old VDG of the Crystal Ball experiment ! ! they have some problems: old device, max. VDG p-energy is 400 KeV out of resonance: -rate reduced by factor  5000