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

2. 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

3. 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

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

6. Background and Sensitivity
Jan 2004 Jan 2005
Gamma Energy (%) *
e+ Timing (nsec) 0.1*
Gamma Timing <0.23* ~0.15**
Gamma Position (mm) *
Gamma acceptance >0.4*
Muon rate (108/sec)
Running Time (107sec) 4.0
Accidental Rate (10-14)
# Accidental Events
90% CL Limit (10-13)
* Measured **w/ new PMTs
More detailed calculation necessary

7. Schedule

8. 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

9. Noise from Zener diode

10. 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.

11. Manpower

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

13. Budget

14. 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

15. PREVIOUS   e g EXPERIMENT
1982 !!

16. 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