Beam test of scintillator strips Miho NISHIYAMA Shinshu University ・ scintillator strip calorimeter ・ Kuraray scintillator strips and KNU extruded ・ the result of DESY beam test ・ KEK beam test ・ results ・ conclusion and plan
Jan 13, 2016
Beam test of scintillator strips
Miho NISHIYAMA
Shinshu University
・ scintillator strip calorimeter・ Kuraray scintillator strips and KNU extruded・ the result of DESY beam test・ KEK beam test・ results・ conclusion and plan
Scintillator strip
4.5cm
1cmMPPC
・ sampling calorimeter scintillator strips + W
・ MPPC : light sensor
・ PFA requires scintillator fine segmented. → We need 10M scintillator strips. Production cost of scintillator strips must be cheap.
Thickness : 0.3cm
Scintillator strip calorimeter
Comparison of scintillator strip
Method Extruded Casting
Production Extrusion Casting
and machining
Character Fiber hole and reflector (TiO2)
are made at the same time.
High accuracy of fiber hole
Problem Accuracy of fiber hole expensive
Company Misung Chemical Company and Kungpook National University
Kuraray
Beam position (mm)
Sig
nal (
AD
C c
ount
s) Casting reflector film Extruded TiO2
Uniformity
Layer #
Strip #
CastingReflector film
ExtrudedTiO2
The result of DESY beam test
Response of MIP
2007 spring…Extruded scintillator strips ・ Light yield is low.・ Uniformity is bad.
Read out : fiber
Signal
(ADC counts)
Fiber – MPPC bad matching
Fiber
Sensitive surface of MPPC
extruded
・ Some extruded scintillator strips have too big fiber hole. ・ Sometimes fiber holes aren’t correctly centered.
Extruded scintillator strips
Too big fiber hole
The objective of KEK beam test
• We’ll use extruded scintillator strips at FNAL beam test in this summer. So we need them because their cost of production is cheap.
• Extruded scintillator strips have some problems.
position and size of fiber hole
Beam test with using carefully chosen extruded scintillator strip was carried out and compared with Kuraray.
KEK Fuji beam line・ Electron beam・ This beam is made form bremsstrahlung photons from KEKB ring・ Beam spot size: ~ 3cm x 4 cm・ Beam energy : 3 GeV ・ Rate: 15Hz @ 3 GeV
beam
Setup
Semiconductor Tracker(borrowed by ATLAS group) 12cm×6cm Resolution vertical : 23μm horizontal: 580μm
Veto counter
Beam e-
Scintillator Fiber Tracker
Trigger countersMovable stage
Scintillator strips
scintillator
Beam e-
Semiconductor Tracker
Scintillator Fiber Tracker
Scintillator strips
Movable stage
Veto counter
Scintillator
Setup of side view
A B C D E F
beam
Scintillator Strips
Method Read-
out
Cover Thickness(mm)
A1
Extruded
Fiber
TiO2
3
No fiber !
A2 good positioning
B1
Reflector
big hole
B2 matched hole
C1 Direct TiO2
D
KurarayDirect
Reflector
2E
3F Fiber reference
• 8 layers with different types of strips• 4 same type strips per one layer
MIP selection
MIP selected strip
spacer
Only pedestal signal
For the selected strip, MIP event must satisfy following conditions: ・ In the same layer, strips show the pedestal signal but the selected strip.
・ In the front and the rear layer, the strips at same position of the selected strip show the MIP signal.
MIP signal
e-
All collected events MIP events
Response for MIP
extruded TiO2
No fiber
extruded TiO2
good matching
extrudedreflectorbad matching
extrudedreflector good matching
extruded TiO2
Kurarayreflector
Kurarayreflectorthickness:2mm
Kurarayreflector
reference
Num
ber
of e
vent
s (lo
g sc
ale)
Signal (ADC counts)
0 5000 0 5000 0 5000
0 0 0 0
0
5000 5000 5000 5000
5000
Response for MIPVariation of strip by strip
Num
ber
of e
vent
s (lo
g sc
ale)
Signal (ADC counts)
All collected events MIP events
Extruded scintillator strip + reflector film good matching
These plots show the variation of strip by strip is big.
Uniformity
extruded TiO2
No fiber
extruded TiO2
good matching
extruded reflector bad matching
extruded reflectorgood matching
extruded TiO2
Kuraray reflector thickness:2mm
Kurarayreflector
Kuraray reflector
reference
Beam position (mm)
Sig
nal (
AD
C c
ount
s)
Beam position (mm)
Sig
nal (
AD
C c
ount
s)Uniformity
Variation of strip by strip
Extruded scintilattor strip + reflector film good matching
These plots show the variations of the uniformity aren’t so big. However light yields aren’t same.
Conclusion
• The position of fiber and MPPC is important.
• Reflector film works better than TiO2 .
⇒ We asked KNU to make extruded scintillator
with the precise size of fiber hole and position
without TiO2 .
Plan
• More detail analysis about KEK beam test is neccesary.
• In this summer, FNAL beam test will be carried out using improved extruded scintillator strips.
Does direct light cause bad uniformity?
1mm
1mm
Direct light 100%
Direct light 25%
1mmφ
Sig
na
l (A
DC
cou
nts
)
Beam position (mm)
Extruded TiO2
Extruded TiO2
Good matching
Setup
PMT
Discriminator Gate Generator
90SrMPPC
ADC
(Vbias = 76.5 [ V])
Trigger scintillator
Thermostatic chamber (25 )℃
Extruded with TiO2
Collimator with2 mmhole
Signal input
Gateinput
AMP (x63)
72 [ns]
Position of-ray source
×x mm
MPPC
57mm
Measurement of 3 types
1mmφ 1mmφ
White paint to shield direct light
KIMOTO reflector to shield direct light
Scintillator with TiO2
Nothing to shield direct light
Result of measurementFiber : 43mmFiber : 57mm + KIMOTO reflectorFiber : 43mm + paint
MPPC side
Conclusion
• Direct light causes bad uniformity.
→ We have the plan
to use the coupler
as the left figure shows.
Using this, direct light is
shielded and the fiber
position becomes stable.
Back up
Extruded scintillator strip with a fiber hole ( A,B )
A1 A2
matched hole B2
bigger hole B1
Type : A covered with TiO2 A1 : fiber - MPPC bad matching A2 : fiber – MPPC good matching
Type : B covered with KIMOTO reflector film B1 : bigger hole B2 : matched hole
MPPCsensitive surface
Scintillator Assembly
scintillator strips 3mm
black sheet
KIMOTO reflector film
frame
frame
spacer
9 strips for a layer 12cm
9cm
FCBWith MPPC
4.5cm
4.5cm
0.4cm1cmThickness 0.3cm
Response for MIP(strip1) All collected events MIP events
extruded TiO2
No fiber
extruded TiO2
extrudedreflector
extrudedreflector
extruded TiO2
Kurarayreflector
Kurarayreflector thickness:2mm
Kurarayreflector
reference
Num
ber
of e
vent
s (lo
g sc
ale)
Signal (ADC counts)
All collected events MIP events
extruded TiO2
No fiber
extruded TiO2
extrudedreflector
extrudedreflector
extruded TiO2
Kurarayreflector
Kurarayreflectorthickness:2mm
Kurarayreflector
reference
Num
ber
of e
vent
s (lo
g sc
ale)
Signal (ADC counts)
Response for MIP(strip3)
All collected events MIP events
extruded TiO2
No fiber
extruded TiO2
extrudedreflector
extrudedreflector
extruded TiO2
Kurarayreflector
Kurarayreflectorthickness:2mm
Kurarayreflector
reference
Num
ber
of e
vent
s (lo
g sc
ale)
Signal (ADC counts)
Response for MIP(strip4)
Response Uniformity (strip1)
extruded TiO2
No fiber
extruded TiO2
extruded reflector
extruded reflector
extruded TiO2
Kuraray reflector thickness:2mm
Kurarayreflector
Kuraray reflector
reference
Beam position (mm)
Sig
nal (
AD
C c
ount
s)
Response Uniformity (strip3)
extruded TiO2
No fiber
extruded TiO2
extruded reflector
extruded reflector
extruded TiO2
Kuraray reflector thickness:2mm
Kurarayreflector
Kuraray reflector
reference
Beam position (mm)
Sig
nal (
AD
C c
ount
s)
Response Uniformity (strip4)
extruded TiO2
No fiber
extruded TiO2
extruded reflector
extruded reflector
extruded TiO2
Kuraray reflector thickness:2mm
Kurarayreflector
Kuraray reflector
reference
Beam position (mm)
Sig
nal (
AD
C c
ount
s)