Guaranteed QoS Synthesiser (GQS) Bob Briscoe, Peter Hovell BT Research Jan 2005.
KEK BT Summary &Plan Shinshu University Miho Nishiyama.
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Transcript of KEK BT Summary &Plan Shinshu University Miho Nishiyama.
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×6cmResolution 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
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.
There are 4 results since we’ve prepared 4 strips read out per one layer.
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.
Sig
na
l (A
DC
co
un
ts)
Beam position (mm)
Direct Photon 25%
1mm 1mmφ
Direct Photon 100%
1mmDirect Photon 25%
4.5cm
0.4cm1cm
Scintillator strip
Sensitive area of MPPC Fiber
Problems were found at KEK BT・ Direct photons caused significant non-uniformity.
MPPC
Conclusion• The position of fiber and MPPC is important.
→ We asked KNU to make extruded scintillator
strips with the precise size of fiber hole and
position .
• Reflector film works better than TiO2 .
→We asked KNU to make scintiilator stirip
without TiO2.
• Direct photons may cause significant non-uniformity.
→Bench test has been done .
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]
KIMOTO reflector
Position of-ray source
×x mm
MPPC
57mm
Measurement of 3 ways
1mmφ 1mmφ
White paint to shield direct light
KIMOTO reflector to shield direct light
Scintillator with TiO2
Nothing to shield direct light
the length of fiber : 43mm Fiber : 57mm Fiber : 43mm
Result of measurementFiber : 43mmFiber : 57mm + KIMOTO reflectorFiber : 43mm + white paint
MPPC side
To look into two peaks…
Check the response for MIP of MPPC side and another.
4.5cm
1cm 1cm
MPPC sideAnother side
extruded TiO2
Good matching
extrudedreflector filmGood matching
Response for MIPN
umbe
r of
eve
nts
(log
scal
e)
Signal (ADC counts)
MIP eventsMIP events (MPPC side)MIP events (another side)
extruded TiO2
extruded TiO2
Good matching
extrudedReflector filmBad matching
extruded Reflector filmGood matching
extruded TiO2
Kuraray(2mm) Kuraray(3mm) Kuraray(3mm)
Plan
• Two peak (~January)
• Comparison of absolute light yield (~March)
• Bias voltage dependence (~March)
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-