Transcript KEK Beam Test Analysis Hideyuki Sakamoto 15th MICE Collaboration Meeting 10st June,2006 Contents • • • • • Setup of KEK beam test Alignment correction Light yield Tracking within B-Field Summary.

KEK Beam Test Analysis
Hideyuki Sakamoto
15th MICE Collaboration Meeting
10st June,2006
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Contents
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•
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Setup of KEK beam test
Alignment correction
Light yield
Tracking within B-Field
Summary
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KEK Beam Test
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•
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Schematic view of detectors
KEK beam test was performed on
located in the beam line
September 30th to October 7th in
2006 at KEK-PS p2 beam line with
the collaboration of UK, US, Europe
and Japan. Main purpose is to
confirm the performance of SciFi
tracker in 1-Tesla solenoid field.
Prototype SciFi tracker
– SciFi tracker is consists of 4
stations, and there are 3 views
for station B,D and 2 views for
station A,C.
VLPCs
– Photon signals from Scintillating
fiber were readout by VLPCs.
– We used two VLPC cassettes.
One of them has high gain and
the other has low gain.
– VLPCs were cooled down to 9K
by a cryocooler.
Prototype SciFi Tracker
3
with 4 Stations
Setup
Readout System
Before installing waveguides
AFE Board
P2 Beam Line
JACEE MAGNET (B=1T)
TOF hodoscope
Cryocooler
BEAM
Low Gain High Gain
Cassette Cassette
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Analysis
Scheme
D C
A
B
BEAM
3 GeV/c p
• This analysis aims to estimate light yield and efficiency. First, fiber
hits are defined on each view. Then, tracks are reconstructed in the 3
stations other than the test station, and are extrapolated to the test
station. Finally, the residual between extrapolated track and the hits
on the test station is calculated. Residual distribution is also
calculated by Monte Carlo to be compared with data.
• Hit definition
– A fiber channel of which measured pulse height is above 2.5
photo-electron is defined as a hit. Most of VLPC noise are
rejected by this cut.
• Tracking
– Track is reconstructed by 2D tracking using 3 stations other than
the test station. Hits on the test station are not included in the
tracking. To select good tracks, chi-squared of the reconstructed
track is required to be less than 1.
• 2D tracking is performed at each Views individually.
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Event Selection
• To ensure that a pion surely
passes through SciFi tracker,
PID by TOF of D1 and D2
counter are required.
• Integration window in Trip chip
is measured. Time difference
from the beam trigger is
restricted to reject events in
which beam particles are not
synchronized to Trip gate.
TOF
D1
SciFi
STATION B
STATION A
D2
STATION C
STATION D
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Alignment Correction
• This study is based on latest mapping table,
Version12.
• Alignment correction as well as mapping error is
checked by finding difference of hit fibers with
fibers which is extrapolated by fitting.
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Alignment Correction
Station B
View V
Fiber #
Residual
View X
View W
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Alignment Correction
View V
Residual
Station A
Fiber #
Residual
View X
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Alignment Correction
View X
Residual
Station C
Fiber #
Residual
View W
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Alignment Correction
Station D
View V
Fiber #
Residual
View X
View W
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Searching for center fiber
• In order to find combination of crossing of fibers of 3 views,
adjustment is done by shifting X-view by same amount.
– Down figure shows the results after shifting by -20 fibers.
W view
#101
V view
#101
X view #81
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Pitches for Station D
• In design, all 3 Views in new 4th Station D has
427 mm pitches. But DATA shows it is 420 mm as
other Views.
Difference of fiber#
V View
Red = 427 mm
X View
Black = 420 mm
W View
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Fiber#
Light Yield –X view
7.9 ±0.1 p.e.
8.8±0.2 p.e.
10.3± 0.2 p.e.
4.7±0.1 p.e.
14.5± 0.4 p.e.
18.6 ±0.9 p.e.
8.5 ±0.6 p.e.
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Light Yield –V view
8.6±0.1 p.e.
9.1±0.1 p.e.
4.7±0.2 p.e.
15.6±0.4 p.e.
15.3±0.4 p.e.
9.1±0.5 p.e.
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Light Yield –W view
9.8 ±0.2 p.e.
9.0±0.1 p.e.
16.8 ±0.4 p.e.
5.1±0.2 p.e.
9.4±0.5 p.e.
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Light Yield Summary
Light Yield
Light Yield
@PROTO
@PION
N
Station
View
Gain of
cassette
3HF
concent.
B
X
LOW
5000
7.9
15.0
1.9
B
V
LOW
2500
8.6
15.6
1.8
B
W
LOW
3500
9.8
16.9
1.7
A
X
LOW
5000
10.3
18.6
1.8
A
V
LOW
5000
9.1
15.3
1.7
C
X
HIGH
mixture
8.8
---
---
C
W
HIGH
5000
8.9
---
---
D
X
HIGH
2500
4.7
8.5
1.8
D
V
HIGH
2500
4.8
9.1
1.9
D
W
HIGH
5000
5.1
9.4
1.8 17
Ratio
Analysis Scheme
• Tracking reconstruction is held by MC in order to
compare with DATA.
– 250 MeV/c muon beam is used for this analysis.
– Initial beam of 4cm x 4cm squared distribution with
Pt=0 are used for MC simulation and beam profile at
TOF hodoscope is compared.
4cmx4cm
• Reconstructed Pt,Pz distribution and chi2
distribution are compared with MC.
T1
TOF
D C
A
B
BEAM
250MeV/c m
1 Tesla
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Beam Profile –MC and
DATA
DATA
MC
Horizontal Width (cm)
10.0
10.0
Vertical Width (cm)
10.0
10.0
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Pt, Pz Distribution – MC
PZ distribution
PT distribution
Station
B
Station
B
Station
A
MeV/c
Station
C
MeV/c
MeV/c
Station
C
Station D
MeV/c
MeV/c
Station
A
MeV/c
Station D
MeV/c
MeV/c
Station @X view
D
C
A
B
Pt (MeV/c)
28.5 (8.6)
29.0 (9.7)
29.4 (10.3)
29.4 (10.0)
Pz (Mev/c)
227.2 (2.3)
226.8 (2.4)
226.4 (2.4)
225.9 (2.4)
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Pt ,Pz Distribution – DATA
PT distribution
electron
muon
Muon
PT distribution
pion
MeV/c
PZ distribution
MeV/c
PZ distribution
MeV/c
MeV/c
Reconstructed mom.
Muon
Pt (MeV/c)
28.3 (10.3)
Pz (Mev/c)
230.7 (26.7)
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Reconstructed Distri. – MC
Reconstructed mom.
Muon
Pt (MeV/c)
30.1 (10.3)
Pz (Mev/c)
233.7 (19.7)
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Chi2 Distribution –MC and
DATA
• Chi2 is defined by residue of hit position and reconstructed track
divided by sigma, 1mm.
• Peaks around 1 is the same as MC. But width is little more broad
than MC. It should be checked.
DATA
MC
Mean
RMS
DATA
2.8
2.3
MC
1.8
1.6
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Summary
• Alignment corrections are done using latest mapping
table, Version12.
• Light yield for all views of all stations are studied by 3D
tracking.
– There is no big difference with 3 kinds of 3HF concentration
(except for StationD).
• Tracking with B-Field are studied.
– Reconstructed Pt, Pz distribution looks like same with MC and
DATA.
– Chi2 distribution of MC also looks like same as DATA, which
confirms that DATA is reconstructed as expected.
– Next step is estimating momentum resolution by MC.
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Backup
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Light Yield
• Light yield is estimated by
fitting the peak with
gaussian.
• Measured light yield is
similar to the result of
cosmic-ray test.
This peak is caused
by ADC saturation.
Station
B
A
C
D
3HF Concentration (ppm)
5000
5000
mixture
2500
Gain of cassette
Low
Low
High
High
Measured light yield (p.e.)
8.1
10.3
8.7
5.1
Data from Cosmic-ray test
8.5
9.1
8.7
n/a
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Residual Distribution
DATA
Station
MC
B
A
C
D
Sigma (mm) @
DATA
1.285 +/- 0.491 +/- 0.505 +/0.009
0.003
0.004
0.635 +/0.004
Sigma (mm) @ MC
1.24 +/0.01
0.535 +/0.005
0.457 +/- 0.434 +/0.004
0.007
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Efficiency
• Efficiency is determined by N1/ N2;
– N1= Number of events which contains fiber hits within the road
width determined at each station
– N2=Number of events with L1A cut & TOF(D1&D2) , and
required fiber hits above 2.5 photo-electron in every views.
Station
B
A
C
D
Road width (mm)
4
2
2
2
Efficiency (%) @ DATA
98.0
98.8
99.5
96.6
Efficiency (%) @ MC
99.92
99.99
100
99.97
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Summary
• KEK beam test was performed in the fall of 2006.
• Stability of VLPC are checked.
–
–
–
–
Pedestal peak is within 1 count,
Pedestal width is within 1-2%,
Gain is stable within 2%, and
Noise rate is within 5-8%.
• Light yield and efficiency are studied with 3GeV/c pion beam without
B-Field.
Station
B
A
C
D
3HF Concentration (ppm)
5000
5000
mixture
2500
Gain of cassette
Low
Low
High
High
Measured light yield (p.e.)
8.1
10.3
8.7
5.1
Light yield from Cosmic-ray
test
8.5
9.1
8.7
n/a
Measured efficiency (%)
98.0
98.8
99.5
96.6
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