Upload
jorryn
View
81
Download
3
Embed Size (px)
DESCRIPTION
MEG 実験用液体 Xe scintillation detector の 40MeV γ 線を用いた性能評価 II. 東京大学 久松康子. 東大素セ、早大理工総研 B 、阪大理 C 、高エ研 D 、 BINP-Novosibirsk E , INFN-PISA F , PSI G 岩本敏幸、大谷航、小曽根健嗣、菊池順 B 、 久野良孝 C 、澤田龍、鈴木聡 B 、寺沢和洋 B 、道家忠義 B 、西口創、 服部紘二 B 、春山富義 D 、真木晶弘 D 、真下哲郎、三原智、 森俊則、八島純 D 、山口敦史 B 、山下了、 - PowerPoint PPT Presentation
Citation preview
MEG 実験用液体 Xe scintillation detector の 40MeV γ 線を用いた性能評価 II
東大素セ、早大理工総研 B 、阪大理 C 、高エ研 D 、BINP-NovosibirskE, INFN-PISAF, PSIG
岩本敏幸、大谷航、小曽根健嗣、菊池順 B 、久野良孝 C 、澤田龍、鈴木聡 B 、寺沢和洋 B 、道家忠義 B 、西口創、
服部紘二 B 、春山富義 D 、真木晶弘 D 、真下哲郎、三原智、森俊則、八島純 D 、山口敦史 B 、山下了、
山下雅樹 B 、山田秀衛、吉村浩司 D 、吉村剛史 B 、A.A.GrebenukE, D.GrigorievE I.IoudineE, D.NicoloF, S.RittG, G.SignorelliF
東京大学 久松康子
2003 年 9 月 12 日 日本物理学会秋季大会
The current status and schedule of MEG experiment
Development of MEG Experiment Detectors* Gamma beam test @PSI* Liq. Xe Calorimeter-Filler study for the Liq. Xe calorimeter* COBRA Magnet Schedule of MEG experimentSummary
Outline
東大素セ、早大理工総研 B 、阪大理 C 、高エ研 D 、BINP-NovosibirskE, INFN-PISAF, PSIG
久松康子、岩本敏幸、大谷航、小曽根健嗣、菊池順 B 、久野良孝 C 、澤田龍、鈴木聡 B 、寺沢和洋 B 、道家忠義 B 、西口創、
服部紘二 B 、春山富義 D 、真木晶弘 D 、真下哲郎、三原智、森俊則、八島純 D 、山口敦史 B 、山下了、山本明 D 、槙田康弘 D 、
山下雅樹 B 、山田秀衛、吉村浩司 D 、吉村剛史 B 、A.A.GrebenukE, D.GrigorievE I.IoudineE, D.NicoloF, S.RittG, G.SignorelliF
Gamma beam test @ PSI
Beam test using the monochromatic gamma beam at PSI πE1 beam line.
*monochromatic γ beam the Energy Calibration
*2γ from the reaction: π0→2γ the absolute timing measurement
* π-p→π0 n
π0(28MeV/c)→γγ
* π-p→nγ
E(γ)=129MeV
kinematics
θ
γ
γEγ
θ
2 gamma rays emitted back to back in lab. frame: 55 & 84 MeV
δEγ/Eγ < 1% θ<5°
5°=87mrad=8.7cm@1m
piE1 beam line @ PSIBeam properties:
Max. momentum: 280 [MeV/c]
Solid angle 32[msr]
Momentum acceptance 7.8%
Momentum resolution 0.8 %
Graphite target
Quadruple Magnet
Dipole Magnet
π-flux:
8 * 105 /sec @ 1.6 mA
expected
Vertical & horizontal slits
Experimental Setup
-- beam
AT
NaI
Timing Counter
target
degrader
counter
Veto counter
Trigger : coincidence
2 Counters
& Timing counter
& Liq.Xe
Liq. Xe
Experimental Setup Cont’dTarget
NaI
Timing Counter
Liq. H2 target
Target cell: 41mm dia. 103mm length
64bars NaI (assembled to form an 8×8array)
63.5×63.5×406 mm3
Position resolution (radial) : σr=4.8 cm @100MeV
Installed in front of NaI detector2plastic scintillators over lapped (5×5cm2)Lead plate (6mm thick)
Prospects
γ beam from π0→2γ will be used to calibrate the Liq. Xe calorimeter in MEG experiment @ piE5, PSIResolution required in MEG experimentBeam Time : Sep. 24th to Dec. 10th
MEG experiment detectorsLiq. Xe calorimeter
Design of liq.Xe calorimeter has almost completed.
The start of the construction: 2004
Subjects to be solved:
Stress, Deformation,
Heat Load, Need of filler
Filler study for the Liq.Xe detector
Some incident photons lose their energy in Liq.Xe, which fills space between the detector wall and PMTs.
To fill the space with materials of long radiation length (“Filler”) will improve the efficiency of this detector.
Liq.Xe
γPMT
PMT cover
(acrylic)
vacuum
Signal cable
PMT holder (G10)
Honeycomb (SUS314)
Incident window
Filler studyRequirement for Filler:
Long radiation length
Do not contaminate liq.Xe
The same expansion coefficient as the glass used in Stem
A mixture of Epoxy resin and glass. Filler is attached directly to the PMT.
Cooling Test
PMT
heater
PMTs with Filler are cooled down to 150K.
The temperature of PMT is controlled by Liq.N2, a cold finger (Cu pipe) and a heater.
Now studying…The difference between the thermal expansion rate of epoxy resin and of SUS.
Stress on the PMT cover
COBRA MagnetSuperconducting coil in cryostat.
potentiometer
Support frame
Compensation coil
COBRA Magnet: Solenoid magnet for positron spectrometer
Gradient field for high rate events
Construction finished!
Final Excitation Test completed.* Magnetic field inside the SC was measured.
→Good Agreement with the calculation!
* Fringe field around the photon detector region was measured.
→Suppressed by compensation coils.
On the axisOn the axis
The Schedule of MEG experimentPhoton detector : Large prototype @PSI background estimation
The construction start in 2004.
COBRA magnet : Shipping to PSI on Sep. 26th
Installation & Engineering runs in piE5
Beam line : Ready by the spring of 2004
Positron tracker : The construction start in 2004.
Electronics & DAQ system : Start assembling in 2004.
All the detectors will be installed in piE5 beam line by 2005.
Engineering runs will start in 2005.
MEG experiment starts at the beginning of 2006.
SummaryBeam test using monochromatic gamma beam starts on Oct. 2nd. The design of the photon detector has almost completed and now studying details. (Filler problems and so on)The construction of COBRA Magnet has finished. (Good performance! )Engineering runs will start in 2005, and MEG experiment at the beginning of 2006.