E05-115 Experimental Setup and...

E05-115 Experimental Setup and Condition

Tomofumi MarutaGraduate School of Science, Tohoku Univ

C2C workshop @ Rome

2009年12月21日月曜日

T. Maruta

Table of Contents‣Kinematics

‣Experimental setup

‣HKS Detector

‣HES Detector

‣Design Resolution

‣Data summary


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Progress of Spectroscopic by (e,e’K+) @ HallC‣ E89-009 (2000): 12!B• Splitter + SOS + Enge• Resolution : 750keV(FWHM)

3

“ A proof of principle”

E89-009 12!B

440h x 0.66µA


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3


E89-009 12!B

440h x 0.66µA

‣ E01-011 (2005): 7!He, 12!B, 28!Al• Splitter + HKS + Enge• Optimization of eʼ acceptance (Tilt method)• Resolution : 400keV(FWHM)• Yield : 10 x E89-009“ Establish the techniques”

Resolution x 2↑Yield x 10↑S/N ratio x 4↑

Preliminary

E01-011 12!B

120h x 24µA


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3


E89-009 12!B

440h x 0.66µA

‣ E01-011 (2005): 7!He, 12!B, 28!Al• Splitter + HKS + Enge• Optimization of eʼ acceptance (Tilt method)• Resolution : 400keV(FWHM)• Yield : 10 x E89-009“ Establish the techniques”

Resolution x 2↑Yield x 10↑S/N ratio x 4↑

Preliminary

E01-011 12!B

120h x 24µA

‣ E05-115 (2009): 7!He, 9!Li, 10!Be, 52!V• New Splitter + HKS + HES• Tilt method“ Precise study in the wide mass region”


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Kinematics of the E05-115 Experiment

4

Momentum: 2.34GeV/c

Central momentum: 0.844GeV/cAngular acceptance: 3°～9°

Central momentum: 1.2GeV/cAngular acceptance : 1°～13°

1.5GeV "*

Scattered electron

K+

Electron beam

M.Q.Tran et al. PLB445 (1998) 20

!

"+p#!+K+

Target nucleus

pCoincidence measurement


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Kinematics of (e, e’K+) programs

5

2004 ～ 2005 2005 2009 2009 ～E94-107 E01-011 E05-115 Mainz

E" (GeV) 2.2 1.5 1.5 1.05W (GeV) 2.2 1.9 1.9 1.67

Q2 (GeV/c)2 0.07 0.01 0.01 0.05Ebeam (GeV) 4.02/3.78/3.66 1.85 2.34 1.50Peʼ (GeV/c) 1.8/1.57/1.44 0.35 0.84 0.455θeʼ (deg) 6 3.7 ~ 5.7 3 ~ 9 15.5

PK+ (GeV/c) 1.96 1.2 1.2 0.466θK+ (deg) 6 1 ~ 13 1 ~ 13 31.4

MainzE94-107

E05-115

E01-011

(E05-115: virtual photon oriented e’ distribution)

M.Q.Tran et al. PLB445 (1998) 20

"+p#!+K+

Q2 (G

eV/c

)2

14 第 2章 (e,e!K+)反応による !ハイパー核分光

ここで、!T、!Lは横波成分 (Transverse)と縦波成分 (Longitudinal)の断面積を、!P、!I は偏極成分 (P)と干渉成分 (I)を表している。また、"は virtual photon flax、"、"Lは偏極の横波成分と縦波成分を表し、式 2.3の 4元運動量移行Qを用いて次の様になる [9][4]。

" =#

2$2Q2

E!

1 ! "

E!e

Ee(2.7)

" =!

1 +2|%q|2

Q2tan2 &e

2

", (2.8)

"L =Q2

'2" (2.9)

E! = ' +Q2

2mN(2.10)

2.2 実験条件2.2.1 Virtual photon energy

図 2.2: p(e,e!K+)!反応の E! 依存性（横軸は Baryon Mass、W[GeV]）[2]。赤い矢印が仮想光子エネルギー '=1.5[GeV/c]の所である。

図 2.2に E! 依存性を示す。これを見ると素過程 p(e,e!K+)!反応の断面積は、Baryon Massが1.7[GeV]"1.9 GeV周辺で最大かつほぼ一定となっている。2009年の夏に実験開始予定のE05-115は、仮想光子のエネルギーを、Baryon Mass#1.9 GeVに相当する#1.5 GeVとなる様に入射ビームエネルギーと、散乱電子の中心運動量を決定した。また、図 2.3、2.4のように、K+ 中間子、Virtual ptohon fluxの散乱電子の角度依存性は共に前方ピークを持っているため、共に出来る限り前方で検出する必要がある。


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CEBAF@JLab

‣Continuous Electron Beam Accelerator Facility

6

HallCHallA

Injector

NorthLinac

SouthLinac

! Continuous Electron Beam Accelerator Facility

Accelerator specification‣ Duty factor : ～100%! comparable hypernuclear yield[/h] to ($+,K+) reaction (100 x σ(e,eʼK) < σ($,K))

‣ Beam energy spread : < 7 x 10-5

‣Bunch energy spread (σ) < 3 x 10-5

‣Energy stability (σ) < 3 x 10-5

! Achievable to good energy resolution of a few 100keV

‣ Beam size (rms): < 100μm

Bird view of CEBAF

time

2nsΔt=0.5ps

Beam configuration～0.5ps bunch in every 2ns CEBAF is unique facility for (e, e’K+)

hypernuclear spectroscopy except for Mainz


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Beamline at Hall-CE05-115:!Pre-chicane configurationMerit : Cleanly transport the beam.Demerit : Photon dump is necessary inside the Hall.

7

E01-011: !Post-chicane configurationMerit : Combine dumps in both photon and beam.Demerit : Huge background around post-chicane area due to beam halo.

Enge

HKS

24

CH

AP

TE

R2.

EX

PE

RIM

EN

TA

LA

PPA

RAT

US

2.3

The

HK

S−Enge

spectrom

eter

system

The

E01-0

11

hypernucle

ar

spectroscopy

system

isestablis

hed

to

achie

ve

hig

hm

ass

energy

res-

olu

tio

nfo

rthe

Λhypernucle

ar

spectroscopy.

It

consis

ts

of

three

magnets

i.e.a

split

ter

magnet,

the

Enge

split

pole

magnet

(E

nge)

and

the

Hig

hresolu

tio

nK

aon

Spectrom

eter

as

show

nin

Fig

.

2.1

2.

The

incid

ent

ele

ctron

(∼1.8

GeV

)in

teracted

wit

ha

target

nucle

us

creats

ahypernucle

us,a

scat-

Fig

ure

2.1

2:

Top(left)

andbird’s

eye(right)

viewof the

JLabE

01-011experim

ental setup.

tered

ele

ctron

and

aposit

ive

kaon.

Scattered

partic

les

are

separated

accordin

gto

their

ele

ctronic

charge

just

aft

er

the

target

by

the

split

ter

magnet

inorder

to

detect

them

at

the

forw

ard

angle

as

the

requir

em

ent

expla

ined

inla

st

sectio

n.

Aft

er

that, ∼

300

MeV

/cscattered

ele

ctrons

are

detected

by

the

Enge, ∼

1.2

GeV

/ckaon

are

de-

tected

by

the

HK

Sw

hic

hconsis

ts

oftw

oquadrupole

magnets

and

adip

ole

.

Table

2.1

sum

mariz

es

the

configuratio

nof

the

E01-0

11

hypernucle

ar

spectroscopy

system

.A

nd

detail

descrip

tio

nofeach

spectrom

eter

com

ponents

are

expla

ined

info

llow

ing

sectio

ns.

2.3

.1Split

ter

magnet

and

target

cham

ber

The

split

ter

magnet

(Fig

.2.1

3)

isused

to

deflect

charged

partic

les

to

the

Enge/H

KS

spectrom

-

eters.

This

spectrom

eter

isa

C-t

ype,norm

alconductin

gdip

ole

magnet

wit

h15.2

4cm

gap

wid

th.

Atarget

cham

ber

wit

ha

target

ladder

isin

stalle

din

to

the

gap.

The

split

ter

magnet

isoperated

by

rem

ote

control,

and

its

field

ism

onit

ored

by

ahall

probe

(G

roup3

DT

M-1

51

[59])

.

Magnetic

field

on

the

mid

-pla

ne

of

the

split

ter

magnet

was

measured

wit

hthe

hall

probe

befo

re

To dump

Beam

Photonline

Target

Enge

HKS

Splitter To beam dump

Photondump

Target

NewSplitter HES

HKS

Beam


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E05-115 setup

8

HKS detector

HES detector

2.344GeVe beam

e’

K+

HES

HKS

Newsplitter

‣ Introduction of Large acceptance electron spectrometer.

‣ Higher electron beam energy acceptable than Enge.

Target


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E05-115 Setup

9

HES

HKS

To Photondump

Beam

To beamdump

NewSPL


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HKS Spectrometer

‣ QQD configuration‣ Momentum acceptance : 1.2GeV/c ±12.5%‣ Solid angle : 11msr‣ !p/p : 2 x 10-4

‣ Angle acceptance : 1 ~ 13 deg‣ Rate capability : 1.5MHz

10Kaon Momentum (GeV/c)

0.9 1 1.1 1.2 1.3 1.4 1.5

Solid

Ang

le (m

sr)

0

2

4

6

8

10

12

14

HKS Solid Angle

Figure 8: Momentum dependence of the solid angle of HKS.

e’ Momentum (GeV/c)0.6 0.7 0.8 0.9 1 1.1 1.2 1.3

Solid

Ang

le (m

sr)

0

1

2

3

4

5

6

7

8

9

HES Solid Angle

Figure 9: Momentum dependence of the solid angle of HES.

66

KQ1

KQ2

KD


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HKS Detectors (Cherenkov Counters)

11

Singles RateSingles Rate$+ 25 kHzK+ 0.2 kHzp 16 kHz

30μA, 12C 100mg/cm2

Based on E01-011

KAC1/2/3 7-seg. Aerogel cherenkovEffective area 46H x 169W x 31T (cm3)Index 1.055

KWC1/2 12-seg. Water cherenkovEffective area 35H x 184.8W x 8T (cm3)Index 1.33

KLC 13-seg. Lucite cherenkovEffective area 42H x 175.5W x 2T (cm3)Index 1.49

New

New

Max. DAQ rate2kHz

Cherenkov counters are for $/p rejection>99.9% $ rejection by AC>99.9% p rejection by WC

AC WC LC

$+ ◯ ◯ ◯K+ × ◯ ◯p × △ △

Ncherenkov ∝1-1/(%n)2

HKS-

D

KDC1 KDC2

KTF1X

KTF1Y KTF2X

KAC KWC

KLC


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KDC1KDC2

KTF1X

KTF1Y

KAC

KTF2X

KWC

HKS Detectors (TOF Counters, DCs)

12

KDC1/2 Planner drift chamberEffective area 30H x 105W x 3.5T (cm3)Layer config 6 (xxʼ, uuʼ, vvʼ)

KTF1X 17-seg. plastic scintiEffective area 30H x 125W x 2T (cm3)

KTF1Y 9-seg. plastic scintiEffective area 27.5H x 125W x 2T (cm3)

KTF2X 18-seg. plastic scinti.Effective area 35H x 170W x 2T (cm3)

HKS-

D

KLC

! TOF resolution of σ=75ps is required for $+/K+ 4σ separation

! flight length 1.5m (KTF1X - 2X)! 1.35GeV/c $+/K+ ΔTOF = 300ps! σ=77ps achieved at test experiment at

KEK-T1


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HES Spectrometer

‣ QQD configuration‣ Momentum acceptance :

0.844GeV/c±17%‣ Solid angle : 7msr‣ Angle acceptance : 3 ~ 9 deg‣ δp/p : 2 x 10-4(FWHM) ‣ Rate capability : 5MHz

13

Kaon Momentum (GeV/c)0.9 1 1.1 1.2 1.3 1.4 1.5

Solid

Ang

le (m

sr)

0

2

4

6

8

10

12

14

HKS Solid Angle

Figure 8: Momentum dependence of the solid angle of HKS.

e’ Momentum (GeV/c)0.6 0.7 0.8 0.9 1 1.1 1.2 1.3

Solid

Ang

le (m

sr)

0

1

2

3

4

5

6

7

8

9

HES Solid Angle

Figure 9: Momentum dependence of the solid angle of HES.

66

EQ1

EQ2

ED


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HES detector package

14

EDC1 Honeycomb, used in 2ndEffective area 12H x 100W x 32T (cm3)Layer config 10 (xxʼ, uuʼ, xxʼ, vvʼ, xxʼ)EDC2 Planner drift chamberEffective area 30H x 105W x 3.5T (cm3)Layer config 6 (xxʼ, uuʼ, vvʼ)EHOD1/2 29 seg. plastic scinti.Effective area 30H x 117W x 1T (cm3)

HES-

D

e’

EDC1EDC2

EHOD1

EHOD1

EHOD1 EHOD2

EDC2

EDC1


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Momentum Correlation‣Momentum acceptance between K+ and eʼ are

decided ! distribution to be diagonal.

15

PK GeV c[ / ]

1 1.05 1.1 1.15 1.2 1.25 1.3 1.35 1.4

1

1.05

1.1

Pe

Ge

Vc

'[/

]

- '

.

E05 115 Pe vs PK

Beam energy 2 344 GeV

0.7

0.75

0.8

0.85

0.9

0.95

!"0

V g s. .!52

0

10

0

20

0

30

0

40

0

50

0

60

0

70

0

80

0

HE

S

0

50

100

150

200

250

300

350

HKS

Figure 5: Momentum correlation between kaon arm and electron arm for hyperons and hypernucleiproduction reaction.

64


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Tilt MethodOptimization of Scattered electron acceptance

16

x’ (mrad)

y’ (m

rad)

ENGE acceptance

-100 -50 50 100 0 0

100

50

x’ (mrad)

y’ (m

rad)

HES acceptance

0 50 100 -50 -100

50

100

0

SplitterEQ1EQ2

‣ Beam Energy : 1.8"2.34GeVBackground electrons go more forward• Beam current #• S/N ratio #‣ Brand-new e’ spectrometer, HES• Enlarge acceptance #• Virtual Photon Yield #

signal

background

Red: SignalGreen: B.G.Blue : B.G.

xʼ (mrad)1000-100 -50 500

yʼ (m

rad) 100

50

E01-011

E05-115


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Tilt MethodOptimization of Scattered electron acceptance

16

x’ (mrad)

y’ (m

rad)

ENGE acceptance

-100 -50 50 100 0 0

100

50

x’ (mrad)

y’ (m

rad)

HES acceptance

0 50 100 -50 -100

50

100

0

SplitterEQ1EQ2

‣ Beam Energy : 1.8"2.34GeVBackground electrons go more forward• Beam current #• S/N ratio #‣ Brand-new e’ spectrometer, HES• Enlarge acceptance #• Virtual Photon Yield #

signal

background

6.5°

Red: SignalGreen: B.G.Blue : B.G.

xʼ (mrad)1000-100 -50 500

yʼ (m

rad) 100

50

E01-011

E05-115


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Design Energy Resolution

17

Target 7Li 10B 12C 52Cr

HKS momentum(keV) 210 210 220 220

HKS angle (keV) 100 70 60 10

HES momentum (keV) 160 160 160 170

HES angle (keV) 90 60 50 10

Beam energy (keV) ≦160≦160≦160≦160

Target (100mg/cm2) ≦100 ≦110 ≦110 ≦90

Overall (keV) ≦350 ≦340 ≦340 ≦330


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Parameters of JLab (e, e’K+) programs

18

2000 2004-5 2005 2009E89-009 E94-107 E01-011 E05-115

Configuration SOS+ENGE+Splitter

HRS+HRS+Septum

HKS+ENGE+Splitter

HKS+HES+New Splitter

Beam intensity (μA) 0.66 100 24 30

Target thickness(mg/cm2) 22 100 100 100

Hypernuclear yield(12!B g.s.) 0.9 2 ～ 3 8( ～ 16) ( ～ 40)

Resolution (keV) 750 ～ 700 ～ 400 ( 3 ～ 400)Beam energy(GeV) 1.7 ～ 1.8 4 1.8 2.34

pK (GeV/c) 1.2 1.9 1.2 1.2peʼ (GeV/c) 0.3 2.2 0.3 0.84θK (deg) 0 ～ 7 6 1 ～ 13 1 ～ 13θeʼ (deg) 0 6 4.5 2 ～ 10

( ): Expectation


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Data summary

19

Target Hypernucleus Thickness (mg/cm2)

Average beam current (uA)

Total Charge (Coulomb)

CH2!& 450.8 2.0 0.28

Water !& ~500 2.7 0.20

7Li 7!He 184.0 32.0 4.84

9Be 9!Li 188.1 38.3 5.33

10B 10!Be 56.1 38.7 6.25

12C 12!B 112.5 26.8 5.90

52Cr 52!V 134.0154.0 7.6 0.83

5.53

Beamtime: Aug./21st～Nov./2nd/2009


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Collaboration Pictures

202009年12月21日月曜日

E05-115 Experimental Setup and...

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