2008Oct10_fuji

リニアコライダー実験のための
細分割カロリメータの開発研究
魚住聖（神戸大） for the ILCCAL group
Oct-10 2008 富士ビームラインでの実験・成果発表会
1. イントロ
2. 富士ビームラインでのテスト
3. その後
Jet Energy Measurement at the ILC experiment
• e+e- collider with center-of-mass energy
at 500 ~ 1000 GeV.
• ILD (International Large Detector) is one of the detector
concepts proposed for the ILC experiment.
• Various precision measurements expected:
– e+e- g H, W, Z, tt, SUSY, etc …
g Multi-jets final states.
• Particle Flow Algorithm (PFA) allows precise
jet-energy measurement
.
ETOT = pe+ p + pcharged hadron + E + Eneutral hadron
[ tracks only]
[calorimeter only]
• Separation of jet particles in the calorimeter is required for the PFA
g Fine granular calorimeter is necessary.
The Scintillator-Strip Electromagnetic Calorimeter
• Sampling calorimeter with Tungstenscintillator sandwich structure.
• Scintillator stirp structure to achieve
fine granularity
• Signal of all the strips are read out
individually..
• Huge Number of channels
(~10M for ECAL, ~4M for HCAL).
g Extruded scintillator + MPPC
are used to reduce production cost.
Scintillator strip
(4.5 x 1 x 0.3 cm)
WLS fiber
MPPC
Beam Test in May 2007 @ DESY
Tungsten
(3.5 mm thick)
Scintillator layer
(3 mm thick)
Scitillator strip performance
@ DESY Beam Test
Response
Extruded
Kuraray
Fiber readout Fiber readout
for MIP
First produced extruded scintillator
strips show
・ Low light yield
• Large non-uniformity
Strip #
Layer #
Signal (ADC counts)
Uniformity of 3 different types of scintillators
Kuraray
Kuraray
Beam position (mm)
Extruded
Extruded scintillatorの
何がいけなかったのか？
考えられる要因 :
• MPPCとファイバーのマッチング
• ファイバー穴の位置と大きさ
• シンチレータの透明度
• 反射材
Beam Test @ KEK Fuji beamline
Objective : Establish the extruded scintillator
Scintillator Assembly
frame
Reflector film
black sheet
Scintillator
strips
0.4cm
MPPC
MPPC
4.5cm
1cm
FlexibleCable
Cable
Flexible
WithMPPC
MPPC
With
Tested Strips
A
B
C
D
E
F
• 8 layers with different types of strips
• 4 strips per one layer were read out.
type
Method
Readout
Cover
Thickness
(mm)
A1
No fiber
TiO2
A2
Fiber
B1
B2
Extruded
C
3
Direct
F
Direct
Kuraray
Fiber
TiO2
2
Reflector
3
A1,A2,….,F
big fiber hole
matched
hole
Reflector
D
E
good
matching
reference
beam
Extruded scintillator strip with a fiber hole
（A,B）
Type : B
Type : A
covered with KIMOTO reflector film
covered with TiO2
B1 : bigger hole
A1 : fiber - MPPC bad matching
B2 : matched hole
A2 : fiber – MPPC good matching
A1
A2
bigger hole
B1
MPPC
sensitive surface
matched
hole
B2
Setup
eBeam
ATLAS SCT
12 cm×6 cm
sx ~ 25 m,
sy ~ 500 m
Sci-Fi Tracker
3x3 cm,
fiber f = 1 mm
Scintillation
counter
3x3 cm
ebeam
Trigger counters
Scintillator
strips
Movable stage
(borrowed from ATLAS group)
Veto counter
Schedule & people
Nov 16th 2007
17th ~ 21th
22th ~ 29th
29th
: kick-off meeting
: Setup & Commissioning
: Data taking (including 4 days of beamtime extension)
: withdrawal
People
D. Kong (KNU)
K. Kawagoe (Kobe)
D. Jeans (kobe)
T. Kaneko (Kobe)
H. Ikeda (Kobe)
K. Ueyama (Kobe)
T. Takeshita (shinshu)
S. Uozumi (shinshu)
M. Nishiyama (Shinshu)
Y. Sudo (Tsukuba)
T. Ikuno (Tsukuba)
H. Yamazaki (Tsukuba)
Y. Takahashi (Tsukuba)
K. Hara (Tsukuba ATLAS)
T. Meguro (Tsukuba ATLAS)
K. Hanawa (Tsukuba ATLAS)
Beam Properties
• Trigger rate ~ 15 Hz (with 6 x 12 cm trigger counters).
• Turning on Q3, Q4 magnets didn’t increase the beam rate.
• Beam spot size ~ 3 x 4 cm on detector surface.
Beam Profile (by ATLAS SCT)
The Data Collected
• Precise position scan
– with uniform bias voltage to
all the MPPCs (=77.0 V).
Position of strips
– 100~600 events collected
in each 1 x 1 mm2 region,
which allows light yield measurement
with 1 ~ 4% of uncertainty.
• Central injection data taken with Vbias=76.0 V and 78.0 V
to see the effect of PDE variation of the MPPC.
• In between each 50k beam data taking, clock-trigger run
is taken to measure pedestal and 1 p.e. peak position.
Number of events (log scale)
Response for MIP
extruded
TiO2
No fiber
0
extruded
TiO2
good matching
5000
0
5000
extruded
reflector
bad matching
0
Kuraray
reflector
thickness:2mm
extruded
TiO2
0
All collected events
MIP events
5000
0
5000
5000
extruded
reflector
good matching
0
5000
Kuraray
reflector
Kuraray
reflector
reference
0
Signal (ADC counts)
5000
0
5000
Signal (ADC counts)
Uniformity
extruded
TiO2
No fiber
extruded
TiO2
extruded
TiO2
good matching
Kuraray
reflector
thickness:2mm
extruded
reflector
bad matching
Kuraray
reflector
extruded
reflector
good matching
Kuraray
reflector
reference
Beam position (mm)
Signal (ADC counts)
Uniformity
Variation of strip by strip
Extruded scintilattor strip＋reflector film
good matching
Beam position (mm)
These plots show the variations of the uniformity aren’t so big.
However light yields aren’t same.
まとめとビームライン使用の感想
• Extruded scintillatorの性能研究のためにビームテストを行い、
有用な結果が得られました。
• ビームスポットは広がっており(~3x4 cm)、トリガーレートは
低かったが(~15Hz)、時間をかけることで必要量のデータを
収集することができました。
• ビームレート、スポットサイズについては今後改善されればと思い
ます。
• Control roomの環境は申し分ありませんでした。
• ビームエリアの温度は非常に良くコントロールされていました。
その後の話
Beam Test in Sep 2008 @ Fermilab
• Objective : Test feasibility of Scintillator-ECAL
with 1-32 GeV e- , p- and - beams.
• Combined test with Scintillator-HCAL
by DESY group.
• CAL prototype consists of
30 layers x 72 strips = 2160 channels in total.
• Fully built with extruded scintillators.
Very Preliminary Results
Electron energy spectra
16 GeV e(ScECAL only)
16 GeV p-
1 3 6 12 16 25 32 GeV
p0 runs
• Ability of p0 reconstruction from 2 is useful to improve jet
energy resolution.
• Generate p0 by putting iron on beamline and injecting 16-32
GeV p- beam.
• Try reconstruction of the generated p0 with Scintillator-ECAL.
p0 ->2
富士ビームラインでのテストによって、
FNALビームテストに向けたプロトタイプ製作に
向けて重要な足がかりを作ることができました。
富士ビームラインに関わる全ての人々に
ILCCALグループ一同深く感謝します。
Silicon trackerやmovable stageを貸して頂いた
ATLAS (KEK, 筑波大)グループの皆様、
また、ビームタイム延長についてわがままを聞いて
頂いたPHENIXグループの方々に
お礼を申し上げます。
Backups
ILC Detector Concepts
• Particle Flow Algorithm (PFA)
LDC
SiD
• Compensation
(Dual-Readout Calorimeter)
5/30/2007
4th
GLD
ILD
?
Three out of four are proposing
a detector which is optimized
for PFA, though the technical
realization is quite different.
Introduction
- Most of the important physics processes to be studied in the ILC
experiment have multi-jets in the final state.
→ Jet energy resolution is the key in the ILC physics.
H→WW*
40% lum. gain
e+e- → ZHH
40% lum. gain
Precision studies of the
Higgs boson will be ILC
bread and butter.
e+e- → ZH → qqbb @ 350GeV, 500fb-1
Invariant mass of two b-quark jets for different jet energy resolution.
→ 40% luminosity gain
5/30/2007
WW scattering,
30~40% lum. gain
LCWS07 @ DESY
26
extruded+fibre @ 3 GeV: energy response vs.
position energy response
2-3 times more variation that
direct+fibre configuration
~30%
energy response [MIPs]
extruded strips are less uniform
Response for MIP
Variation of strip by strip
Number of events (log scale)
There are 4 results since we’ve prepared 4 strips read out per one layer.
Extruded scintillator strip＋reflector film
good matching
All collected events
MIP events
Signal (ADC counts)
These plots show the variation of strip by strip is big.

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