MICE Collaboration Meeting　8th Octorber 2006 1

KEK Beam Test Analysis

Hideyuki Sakamoto

16th MICE Collaboration Meeting

8th October 2006

MICE Collaboration Meeting　8th Octorber 2006 2

Contents

• Comparing fitted results with MC and Data– Chi2 Distribution– Residual Distribution

• Pz Resolution

• Pt Resolution

• Summary

MICE Collaboration Meeting　8th Octorber 2006 3

Track Reconstruction• Assuming “Uniform B-Field” and “NO scattering”• Chi2 to be minimized

– Input: xi,yi, i=1,4– Output: x0,y0,p0,R,L– Degree of freedom: 8-5=3

2

2fiti

2

2fiti

i

2 )y(y)x(x

]/LRcos[zxx 0ifit 0

/(0.3B)p R T

/(0.3B)p L L

]/L[zRsin yy 0ifit 0

x0, y0

0

#4

#3 #2

#1

R

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Chi-squared Distribution

MCDATA

D.o.f.=3 chi2 distribution

Sig=0.82mmSig=0.97mm

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Residual – MC –325MeV/c 6degree

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Residual – DATA –325MeV/c 6degree

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Summary of Residual for X

Fitted_Mean

DATAMC

Fitted_Sigma250MeV/c

325MeV/c

400MeV/c

MICE Collaboration Meeting　8th Octorber 2006 8

Summary of Residual for Y

Fitted_Mean

DATAMC

Fitted_Sigma250MeV/c

325MeV/c

400MeV/c

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P_TOF P_fit =√(Pt_fit)^2+(Pz_fit)^2 ~ (Pz_fit)

• Pz resolution is estimated by comparing the fitted momentum with the DATA from TimeOfFlight.

– P_TOF is the momentum calculated from TimeOfFlight at the TOF hodoscope

– Pt_fit / Pz_fit is the fitted momentum horizontal / perpendicular to the tracker’s plane

Pz Resolution

Beam line

Pz_fit

Pt_fitP_TOF

TOF Hodoscope Tracker

MICE Collaboration Meeting　8th Octorber 2006 10

Momentum Distribution calculated from TimeOfFlight

• Momentum (P_TOF) is calculated by TimeOfFlight data measured at TOF hodoscope. electron

muon pion

P_TOF =M

√cT/L (cT/L+2)

c: speed of light

M: mass of muon

L: distance (T1 TOFhodoscope)

T: TimeOfFlight (T1 TOFhodescope)

Assuming that beta for electrons is nearly 1.

muon

250MeV/c,6degree, TOF#2

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Pz Error – MC –

_fit = 6%

250MeV/c,6degree, TOF#2

MICE Collaboration Meeting　8th Octorber 2006 12

Pz Error – DATA –

_fit = 8%

250MeV/c,6degree, TOF#2

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Pt Resolution

• It is difficult to estimate Pt resolution from DATA, because there is no direct observable value for Pt.

• Pt resolution could be estimated easily, if the spread of Pt distribution is narrow.

• ….But DATA shows broad distribution.• So, in order to make the beam be sharp, CUT by the

hit position at the TOF hodoscope will be applied.

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Pt Distribution

PZ

6 degree rotated 3 degree rotated

DATA DATA

MC

250MeV/c

MC

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Pt Distribution with TOF cut 6

7

8

9

10

1 2 3 4 5

TOFV

TOFH

Data_fit MC_fit

@ TOFH#2

400MeV/c 3degree

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Pt Distribution with TOF cut 6

7

8

9

10

1 2 3 4 5

400MeV/c 3degree

TOFV

TOFH

@ TOFH#3

Data_fit MC_fit

MICE Collaboration Meeting　8th Octorber 2006 17

Pt Distribution in each TOF hodoscope cell

400MeV/c 3degree

DATA (3deg.)

MC (3.5deg.)

MC (3deg.)

Mean

Sigma

MC result for 3.5 degree becomes more close to Data than that of 3.0 degree. So, it suggests that JC magnet was set with more angled.

6

7

8

9

10

1 2 3 4 5

TOFV

TOFH

Data_fit@ TOFH#2

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Summary

• Pt and Pz resolution are studied using ‘helical fitting’.• Pz resolution is estimated at 8% by comparing with

TimeOfFlight measured at TOF hodoscope.• Pt resolution is difficult to be estimated due to wide-spread

distribution. So, TOF CUT by hit position is applied, which makes the beam to be narrow and be divided into several peaks. In the study so far, it is found that MC and Data will looks similar. Estimating the pt resolution is the next step…