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


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


PDG


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


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


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


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


Analysis

•Timing •Calibration •Hit Decision •Efficiency •Acceptance


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


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


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


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


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]

Year-End Presentation 2018Tomoo Mari

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

!15

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


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


Back up


Acceptance

Geometrical acceptance (S・Ω)Acceptance (ε・S・Ω)

F(θ) =N(θ)ϵ S Ω

12e-6 7e-5


Statistics

[degree]θ0 10 20 30 40 50

#eve

nts

0

2000

4000

6000

8000

10000

z=-230 mmz=-230 mm


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


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

measurement of the cosmic ray zenith angular...

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