Transcript 3HF蛍光体を添加したSci-Fiの基礎開発

3HF蛍光体を添加したSci-Fiの基礎
開発
大阪大学大学院理学研究科
坂本英之
阪大理 (A) 青木正治 有本靖 久野良孝 栗山靖敏
田窪洋介 中丘末広 中原健吾 堀越篤
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
2005/3/27
佐藤朗
松島朋宏
吉田誠
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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 MICE
 MICE


International collaboration experiment (starting from 2006 @RAL)
Measurement of emittance reduction

Trackers back & forward cooling channel
MICE Scintillating Fiber (SciFi) Tracker
Experimental Setup of MICE
SC solenoid（5T）
Absorber（liquid hydrogen）
μ
Tracker
[ emittance measuring ]
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ＲＦ-cavity（200ＭＨｚ）
Tracker
[ emittance measuring ]
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The MICE collaboration
 141 physicists and engineers from 40 institutions in 9 countries
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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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MICE SciFi Tracker
 R&D with UK, US and Japan
 Components

Station

3HF doped 0.35mm-phi scintillating fiber
Station
 Waveguide
Waveguide

4m-long optical clear fiber
 Photon detector
 VLPC (Visible Light Photon Counter)
 High Q.E. 80% at 3HF emission peak (530nm)
To photon
detector
 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)
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Cathode: GaAsP (5mm-phi effective area)
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Anode: 8 stages
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Gain: 3×10^6 @800V
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Quantum efficiency: 50% @530nm
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Experimental setup
 Beam
 1.2 GeV/c
 Pion, proton, ….
 Trigger

Beam
TOF & Defining counters
 Setup of scintillating fibers
Dark box
Sci-Fi
D3
D1 D2
TOF1
1.2 GeV/c
•p
•π+
TOF2
1.5m
4m

0.42-mm pitch with double layer and 4m-long waveguide
 PMT gain monitor by LED
 Mounted in dark box
350um
Side view
Front view
mirror
Optical connector
420um
PMT
scifi
Double layer
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2cm×2cm
defined beam
clear fiber
LED
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Analysis
 Pion selection by TOF → Events in ADC gate → P.E. conversion by LED calibration
TDC histogram
ADC histogram
Subtracted histogram
TDC count
# of events
Off-time
# of events
# of events
ADC gate
1.5
ADC count
P.E.
 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.
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Light yield (p.e.)
A
B
1.5 p.e. cut
sys.err.
w/o cut
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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
# of p.e.
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)
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
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Difference of path length
 Waveguide
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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 waveguide
8.5 (0.5)
8.0 (0.4)
Single layer
w/ waveguide
3.8 (0.6)
3.2 (0.5)
Double layer
w/o waveguide
11.2 (0.5)
9.6 (0.4)
Double layer
w/ waveguide
5.2 (0.4)
4.4 (0.5)
Expected light yield
at MICE
8.3 (0.6)
7.0 (0.8)
99.7%
99.3%
Efficiency
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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
T553
5.2 (0.4)
4.4 (0.5)
MICE (Expected)
8.3 (0.6)
7.0 (0.8)
99.7%
99.3%
Efficiency
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2500 ppm
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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
e
 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→ νν
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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.
VLPC quantum efficiency
Absorption and emission spectrum of 3HF
Quantum Efficiency [%]
VLPC vs PMT QE
80
70
60
50
40
30
20
10
0
0.16
0.14
0.12
0.1
0.08
0.06
0.04
0.02
0
200
300
400
500
600
Wavelength [nm]
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700
PMTQE [%]
VLPCQE [%]
ZD4323
3HF
800
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PMT gain calibration


Measuring the gain
Monitoring of gain stability
 Gain
 # of p.e. per ADC count
 # of p.e. =
(MEAN/RMS)^2
From Poisson distribution
Number of P.E.
 Purpose
 10 % discrepancy was confirmed
by position dependence of gain
 Systematic error from PMT is
less than 5 %
Run number
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Data from Scifis
ADC count
ADC-TDC scatter plot
Proton hit
ADC histogram
Pion hit
ADC count
Background
•Phosphorescence
TDC count
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Effect of double layer
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Layout of SciFi Station
u
V
30cm
W
Side view
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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
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