Measurement of the Cosmic Ray Zenith Angular...
Transcript of Measurement of the Cosmic Ray Zenith Angular...
Year-End Presentation 2018Tomoo Mari !1
Measurement of the Cosmic Ray Zenith Angular Distribution
Tomoo Mari Yamanaka Group
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Introduction
Cosmic ray muon • • Zenith angle distribution ∝ • n is known as ~2 for muon
Flux •
• N : Detected # of events • ε : efficiency • S : surface of the detector • Ω : solid angle
π → μ + νμcosn θ
θ
μ
d(θ) =d(θ = 0)cos(θ)
F(θ) =N(θ)ϵ S Ω Acceptance
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PDG
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Motivation
• Plenty of cosmic ray data • In order to study responses of CsI calorimeter at different depths
• Something else, especially not related to my study... • Analyze Zenith angular distribution of cosmic rays
• Do not use MC method as much as possible
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Setup
CsI calorimeter
2000 mm 50 mm
μ
1800 mm
2595 mm
• KOTO Detector • J-PARC, inside concrete shields • Main ring : sea level - 2 m
• CsI calorimeter • 1800 mm in diameter • 2240 small crystals (25×25 mm2) • 476 large crystals (50×50 mm2)
• Plastic scintillation counter • 2000×100×50 mm3 • 6 counters on the top and bottom • Cover the whole calorimeter
• Read out from both-end with PMTs
• DAQ • 125MHz FADC = 8ns sampling
Plastic scintillator
y
z
y
x
Collaboration Meeting 15/12/2018Tomoo Mari !6
Setup
Top BottomCsI Calorimeter
bef. setting support structures
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Online Trigger
CsI
OR of bottom PMTs
OR of top PMTs
AND
PMTPMTphoton Hit
PMT peak height (left vs right)
1000
1000 [ADC count]
[ADC count]
Online hit decision • Peak height of either PMT > 1000 count
Trigger logic
Trigger rate
~ 2Hz
Peak time should be within 32 ns
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Data
21
全実工程31日
01
234
59,811,1013,1215,1417,1619,1821,2023,2225,2427,2629,2831,3012,1314,1516,1718,1920,2122,2324,2526,2728,29
01
2,34,5
981011
6,7
Cabli 21
全実工程31日
01
234
59,811,1013,1215,1417,1619,1821,2023,2225,2427,2629,2831,3012,1314,1516,1718,1920,2122,2324,2526,2728,29
01
2,34,5
981011
6,7
21
全実工程31日
01
234
59,811,1013,1215,1417,1619,1821,2023,2225,2427,2629,2831,3012,1314,1516,1718,1920,2122,2324,2526,2728,29
01
2,34,5
981011
6,7
21
全実工程31日
01
234
59,811,1013,1215,1417,1619,1821,2023,2225,2427,2629,2831,3012,1314,1516,1718,1920,2122,2324,2526,2728,29
01
2,34,5
981011
6,7
21
全実工程31日
01
234
59,811,1013,1215,1417,1619,1821,2023,2225,2427,2629,2831,3012,1314,1516,1718,1920,2122,2324,2526,2728,29
01
2,34,5
981011
6,7
21
全実工程31日
01
234
59,811,1013,1215,1417,1619,1821,2023,2225,2427,2629,2831,3012,1314,1516,1718,1920,2122,2324,2526,2728,29
01
2,34,5
981011
6,7
21
全実工程31日
01
234
59,811,1013,1215,1417,1619,1821,2023,2225,2427,2629,2831,3012,1314,1516,1718,1920,2122,2324,2526,2728,29
01
2,34,5
981011
6,7
21
全実工程31日
01
234
59,811,1013,1215,1417,1619,1821,2023,2225,2427,2629,2831,3012,1314,1516,1718,1920,2122,2324,2526,2728,29
01
2,34,5
981011
6,7
21
全実工程31日
01
234
59,811,1013,1215,1417,1619,1821,2023,2225,2427,2629,2831,3012,1314,1516,1718,1920,2122,2324,2526,2728,29
01
2,34,5
981011
6,7
21
全実工程31日
01
234
59,811,1013,1215,1417,1619,1821,2023,2225,2427,2629,2831,3012,1314,1516,1718,1920,2122,2324,2526,2728,29
01
2,34,5
981011
6,7
21
全実工程31日
01
234
59,811,1013,1215,1417,1619,1821,2023,2225,2427,2629,2831,3012,1314,1516,1718,1920,2122,2324,2526,2728,29
01
2,34,5
981011
6,7
21
全実工程31日
01
234
59,811,1013,1215,1417,1619,1821,2023,2225,2427,2629,2831,3012,1314,1516,1718,1920,2122,2324,2526,2728,29
01
2,34,5
981011
6,7
21
全実工程31日
01
234
59,811,1013,1215,1417,1619,1821,2023,2225,2427,2629,2831,3012,1314,1516,1718,1920,2122,2324,2526,2728,29
01
2,34,5
981011
6,7
21
全実工程31日
01
234
59,811,1013,1215,1417,1619,1821,2023,2225,2427,2629,2831,3012,1314,1516,1718,1920,2122,2324,2526,2728,29
01
2,34,5
981011
6,7
• 14 CsI channel configurations • Total measurement time is roughly estimated to be 28 days
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Analysis
•Timing •Calibration •Hit Decision •Efficiency •Acceptance
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Definition of timingConstant Fraction Time (CFTime) • Peak height is calculated by fitting 3 points around the maximum sample with quadratic function (Parabolic fitting) • Get timing when a waveform cross 0.5×PeakHeight level to suppress time-walk effects
0.5×Peak height
CFTime
Parabolic fitting
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Calibration
Hit position of the trigger counters ⇄ ΔT btw. both PMTs ☞ Select almost vertical tracks reconstructed from only CsI crystals ☞ Correlation btw. ΔT and reconstructed x position
PMTPMT
PMTPMT
early late
earlylate
0
2
4
6
8
10
12
14
16
18
20
Counter 0
x [mm]1000− 800− 600− 400− 200− 0 200 400 600 800 1000
T [n
s]Δ
50−
40−
30−
20−
10−
0
10
20
30
40
50 hall0Entries 1059Mean x 186.7− Mean y 0.2516− RMS x 327.2RMS y 3.748
0
2
4
6
8
10
12
14
16
18
20hall0Entries 1059Mean x 186.7− Mean y 0.2516− RMS x 327.2RMS y 3.748
Counter 0
Reconstructed x [mm]
ΔT [ns]
within ±50 mm
2595 mm
2000 mm ⇄ 20 ns
x [mm]800− 600− 400− 200− 0 200 400 600 800
Res
olut
ion
[mm
]
0
50
100
150
200
250
Counter 6Counter 6
σposition = 50 ~ 150 mm
gaussian sigma of Projection distribution
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Hit Decision
Selection Comments
Peak height > 1000 count
Peak height (the other side)> 50 count
Gain the resolution of timing differencebtw. left and right PMTs
CFTime ∈ 31±4 clock The same coincidence windowas the online trigger
Peak time - CFTime ∈ (35, 40) ns Remove broken waveformsdue to DAQ problem
Selection Comments
Energy deposit > 5σpedestal Assuming 15 MeV/MIP for small crystal
Trigger counter
CsI crystal
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Trigger Efficiency
Position dependence of the trigger efficiency (= relative efficiency)
3 4 50 1 2
3 4 50 1 2
ϵ0ϵ′�0 ϵ0ϵ′�1 ϵ0ϵ′�5
12 variables : , ⇄ 36 tracks (equations)
ϵ0 ∼ ϵ5 ϵ′�0 ∼ ϵ′ �5χ2(x) = ∑
track (N(x) − N0 ϵtop(x) ϵbtm(x)
N0 )2
y
z
y
x
Vertical tracks
x [mm]1000− 800− 600− 400− 200− 0 200 400 600 800 1000
Rel
ativ
e ef
ficie
ncy
0
0.2
0.4
0.6
0.8
1
Normalized #hit
Efficiency
x [mm]
0.3
Scaled to 1
#hit Efficiency
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Result
• Require 1 hit for each top and bottom counters • Vertical tracks in y-z plane are selected • CsI calorimeter is not used for tracking
3 4 50 1 2
3 4 50 1 2
Vertical tracks
y
z
z [mm]200− 100− 0 100 200
Ord
er
0
1
2
3
4
5
6
Order of cosine / ndf 2χ 22.72 / 5
Prob 0.0003813p0 0.0398± 4.075
/ ndf 2χ 22.72 / 5Prob 0.0003813p0 0.0398± 4.075
Order of cosine
<n> = 4.08 ± 0.04 [degree]θ
0 5 10 15 20 25 30 35 40
]-1
sr-1 s
-2Fl
ux [m
0
20
40
60
80
100
120
140
160
180
200
220
z=-230 mm / ndf 2χ 800.1 / 23
Prob 0Constant 0.8179± 170.8 Cosine degree 0.1032± 3.894
/ ndf 2χ 800.1 / 23Prob 0Constant 0.8179± 170.8 Cosine degree 0.1032± 3.894
z=-230 mm
θ[deg]
Flux [m
-2s-1 sr-1]
func ∝ cosn(θ)
z [mm]
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x [mm]1000− 800− 600− 400− 200− 0 200 400 600 800 1000
Rel
ativ
e ef
ficie
ncy
0
0.2
0.4
0.6
0.8
1
Normalized #hit
Efficiency
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Discussion (1)Attenuation in CsI calorimeter should be considered to estimate the efficiency • Visible count rate decrease as flight length in the calorimeter increase ☞ This attenuation should be considered track by track.
1.6 GeV @ MIP (if vertical)
Less energy deposit
increase w/o CsI
CsI 4.5 g/cm3
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Discussion (2)
Tracking using CsI calorimeter • Much higher granularity (small : 2.5 cm, large : 5.0 cm) • Angle distributions reconstructed from trigger counter and CsI calorimeter depends on CsI configurations → give up to use the calorimeter in this analysis • Fixed configuration
Top/Bottom correlation in efficiency • Efficiency is calculated from # of tracks ☞ Strong correlation btw. top and bottom counters • It’s better to measure their efficiencies directly
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Back up
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Acceptance
Geometrical acceptance (S・Ω)Acceptance (ε・S・Ω)
F(θ) =N(θ)ϵ S Ω
12e-6 7e-5
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Statistics
[degree]θ0 10 20 30 40 50
#eve
nts
0
2000
4000
6000
8000
10000
z=-230 mmz=-230 mm
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Position Resolution
x [mm]1000− 500− 0 500 1000
Posi
tion
reso
lutio
n [m
m]
0
50
100
150
200
250
300
Counter 6Counter 6
Gaussian sigma of residual btw. trigger hit position and CsI track
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Timing Resolution
x [mm]1000− 500− 0 500 1000
Mea
n tim
e re
solu
tion
[ns]
0
0.2
0.4
0.6
0.8
1
1.2
1.4
Counter 0Counter 0
x [mm]1000− 500− 0 500 1000
Mea
n tim
e re
solu
tion
[ns]
0
0.2
0.4
0.6
0.8
1
1.2
1.4
Counter 6Counter 6