2005/3/271 3hf 蛍光体を添加した sci-fi の基礎 開発 阪大理 (a) 青木正治 有本靖...
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3HF蛍光体を添加した Sci-Fiの基礎開発
阪大理 (A) 青木正治 有本靖 久野良孝 栗山靖敏 佐藤朗 田窪洋介 中丘末広 中原健吾 堀越篤 松島朋宏 吉田誠高エ研 (B) 五十嵐洋一 横井武一郎 吉村浩司FNAL (C) Alan Bross
Imperial College London (D) Ken Long, Malcolm Ellis
大阪大学大学院理学研究科 坂本英之
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Contents MICE (Muon Ionization Cooling Experiment)
MICE SciFi Tracker 3HF doped 0.35mm-phi scintillating fiber
KEK Beam Test (T553) Setup Analysis Results
Summary
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MICE (Muon Ionization Cooling Experiment) Ionization cooling of muon
Neutrino Factory Never been practiced… demonstration by MICEMICE
MICE International collaboration experiment (starting from 2006 @RAL) Measurement of emittance reduction
Trackers back & forward cooling channel MICE Scintillating Fiber (SciFi) Tracker
Absorber( liquid hydrogen)SC solenoid( 5T)
Tracker TrackerRF -cavity( 200MHz)[ emittance measuring ] [ emittance measuring ]
μ
Experimental Setup of MICE
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The MICE collaboration 141 physicists and engineers from 40 institutions in 9 countries
Belgium: UC Louvain France: CEA/Saclay Italy: INFN Bari, Frascati, Genoa, Legnaro, Milano, Napoli, Padova, Roma, III, Trieste Japan: KEK, Osaka U Netherlands: NIKHEF Russian Federation: BINP CERN Switzerland: U Geneve, ETH-Zurich, PSI UK: Brunel, Edinburgh, Glasgow, Liverpool, Imperial, Oxford, Sheffield USA: ANL, BNL, Fairfield, Chicago, Fermilab, IIT, JLab, LBNL, UCLA, Northern Illinois,
Iowa, Mississippi, UC Riverside
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To photon detector
Waveguide
Station
MICE SciFi Tracker R&D with UK, US and Japan
Components Station
3HF doped 0.35mm-phi scintillating fiber Waveguide
4m-long optical clear fiber Photon detector
VLPC (Visible Light Photon Counter) High Q.E. 80% at 3HF emission peak (530nm)
Requirement Higher efficiency
e.g., 99.7% efficiency @8p.e.
Checking light yield by beam test
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T553 beam test KEK-PS T1 beam line, April-May 2004
Purpose Selecting best 3HF concentration on light yield And confirming enough high light yield
Scintillating fibers Kuraray SCSF-3HF, 0.35mm-phi, multi-cladding and S-type Base: polystyrene (99%) First dopant: p-terphenyl (1%) Second dopant: 3HF (2500, 4500, 5000, 7500, 10000ppm)
Photon detector PMT (HAMAMATSU R7411U-40MOD)
Cathode: GaAsP (5mm-phi effective area) Anode: 8 stages Gain: 3×10^6 @800V Quantum efficiency: 50% @530nm
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Beam 1.2 GeV/c Pion, proton, ….
Trigger TOF & Defining counters
Setup of scintillating fibers 0.42-mm pitch with double layer and 4m-long waveguide PMT gain monitor by LED Mounted in dark box
Experimental setup
1.5m4m
1.2 GeV/c
TOF2 Sci-Fi TOF1D1
Dark boxD2
• p •π+
Beam D3
mirror
PMT
Optical connector
scifi
clear fiber2cm×2cm
defined beam LED
Front viewSide view
420um
350um
Double layer
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Analysis Pion selection by TOF → Events in ADC gate → P.E. conversion by LED calibration
Background rejection Subtracting using off-time ADC spectrum But still remains… ⇒ cutting under 1.5 p.e.
Number of p.e. Mean of A (w/ cut) and B (w/o cut) Systematic error is 4% @ 8 p.e.
1.5 p.e. cut
w/o cut
Light yield (p.e.)
sys.err.A
B
# o
f events
ADC count
ADC histogram Subtracted histogram
# o
f events
P.E.1.5TDC count
# of
eve
nts
TDC histogram
Off-time
ADC gate
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3HF concentration dependence Selecting best 3HF concentration on light yield
5000 ppm has highest light yield But there was no significant difference among other concentrations
3HF concentration
# of p.e.
2500 ppm 8.0 (0.4)
4500 ppm 8.3 (0.4)
5000 ppm 8.5 (0.5)
7500 ppm 7.1 (0.5)
10000 ppm 7.7 (0.4)
# o
f p.e
.
3HF concentration (ppm)
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Expected light yield at MICE scifi tracker At MICE scifi tracker
Double layer 5.2/3.8=1.37@5000ppm Difference of path length
Waveguide 3.8/5.2=0.45@5000ppm Attenuation of clear fiber
VLPC readout 5.2×80%÷50%=8.3 p.e. Efficiency
1-P(0,8)-P(1,8)=99.7% @8p.e.
P(n, μ) = μn exp(-μ) / n!
Poisson distribution
3HF concentration 5000 ppm 2500 ppm
Single layer
w/o waveguide8.5 (0.5) 8.0 (0.4)
Single layer
w/ waveguide3.8 (0.6) 3.2 (0.5)
Double layer
w/o waveguide11.2 (0.5) 9.6 (0.4)
Double layer
w/ waveguide5.2 (0.4) 4.4 (0.5)
Expected light yield at MICE
8.3 (0.6) 7.0 (0.8)
Efficiency 99.7% 99.3%
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Summary MICE scifi tracker based on 3HF doped 0.35mm scintillating fibers will be used
KEK beam test (T553) was performed in April-May 2004 5.2 ± 0.4 p.e. @5000ppm (double layer with 4m-long waveguide) 4.4 ± 0.5 p.e. @2500ppm (double layer with 4m-long waveguide)
From T553, Over 99% efficiency will be expected at MICE with 5000ppm and also 2500ppm These meet the requirement of MICE scifi tracker
3HF concentration 5000 ppm 2500 ppm
T553 5.2 (0.4) 4.4 (0.5)
MICE (Expected) 8.3 (0.6) 7.0 (0.8)
Efficiency 99.7% 99.3%
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END
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Neutrino Factory Physics
Precise measurement of the MNS matrix element Observation of the matter effect
the sign of Δm232
leptonic CP violation
Neutrino production Goals
(Eν)max = 50 GeV
10^20 muon decays/year Advantages
Precise known energy spectrum
and flavor composition High-energy electron neutrinos
Need “cooling” of muons Accelerating intense muon beam by reduction of emittance (cooling) Fast cooling is essential before decaying of muons Ionization cooling !
μ→e νν
Cooling !
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3HF scintillating fibers VLPC can detect green lights (500-600 nm) at most.
Doping 3HF as a wavelength shifter; 350 nm 530 nm⇒ Doping with high concentration in order to improve the absorption efficiency.
Absorption and emission spectrum of 3HFVLPC vs PMT QE
01020304050607080
200 300 400 500 600 700 800
Wavelength [nm]
Quan
tum
Efficie
ncy
[%]
00.020.040.060.080.10.120.140.16
PMTQE [%]VLPCQE [%]ZD43233HF
VLPC quantum efficiency
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PMT gain calibration
Purpose Measuring the gain Monitoring of gain stability
Gain # of p.e. per ADC count # of p.e. = (MEAN/RMS)^2 From Poisson distribution
10 % discrepancy was confirmed by position dependence of gain
Systematic error from PMT is less than 5 %
Num
ber
of
P.E
.
Run number
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Data from Scifis
Background
ADC-TDC scatter plot
TDC count
AD
C c
ou
nt
•Phosphorescence
ADC histogram
ADC count
Proton hit
Pion hit
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Effect of double layer
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30cm
Side view
Layout of SciFi Station
u
V
W
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Ionization Cooling
Fast cooling is possible Best method for muon cooling
Principle Passing through absorber (loss total momentum)
followed by RF (restore longitudinal momentum) Result in reduction in p ⊥ spread ,i.e. (transverse) cooling
Z
X