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E05-115: Third Generation Hypernuclear Experiment

Hall C User MeetingJanuary 18th, 2008 (Fri)Yu FujiiTohoku Univ.

E05-115 : Spectroscopic investigation of hypernuclei in the wide mass region using the (e,e’K+) reaction

JLab E05–115 collaborators in proposal

~ 87 researchers from 19 institiutes

Dept. of Phys. Tohoku Univ.

Y. Fujii, O. Hashimoto, H. Kanda, M. Kaneta, D. Kawama, K. Maeda,

N. Maruyama, A. Matsumura, S.N. Nakamura, K. Nonaka, Y. Okayasu,

M. Sumihama, H. Tamura, K. Tsukada, Y. Miyagi

Dept. of Phys. Hampton Univ.

O.K. Baker, L. Cole, M. Christy, P. Gueye, C. Jayalath, C. Keppel,

S. Malace, E.K. Segbefia, L. Tang, V. Tvaskis, L. Yuan

Dept. of Phys. Florida International Univ.

A.Acha, W. Boeglin, L. Kramer, P. Markowitz, N. Perez, B. Raue,

J. Reinhold, R. Rivera

Dept. of Phys. Yamagata Univ.

S. Kato

Institute of Particle and Nuclear Physics (KEK)

H. Noumi, Y. Sato, T. Takahashi

Laboratory of Phys, Osaka Electro-Comm. Univ.

T. Motoba

Dept. of Phys. Univ. of Houston

Ed. V. Hungerford, K.J. Lan, Y. Li, N. Elhayari, S. Randeniya, N. Klantrains

Thomas Jefferson National Accelerator Facility

P. Bosted, R. Carlini, V. Dharmawardane, R. Ent, H. Fenker, D. Gaskell,

M. Jones, D. Mack, J. Roche, G. Smith, W. Vulcan, S. Wood, C. Yan

Yerevan Physics Institute

R. Asaturyan, H. Mkrtchyan, A. Margaryan, S. Stepanyan, V. Tadevosyan

Nuclear Physics InstituteLanzhou Univ.

X. Chen, B. Hu, S. Hu, Y. Song, W. Luo, B. Wang

Dept. of Physics / Applied Phys. Univ. of Zagreb

D. Androic, M. Furic, T. Petkovic, M. Planinic, T. Seva

Dept. of Phys. North Carolina A&T State Univ.

A. Ahmidouch, S. Danagoulian, A. Gasparian

Dept. of Phys. Louisiana Tech Univ.

N. Simicevic, S. Wells

Dept. of Phys. James Madison Univ.

G. Niculescu, M.-I. Niculescu

Dept. of Phys. Univ. of North Carolina at Wilmington

L. Gan

Dept. of Phys. Duke Univ.

M.W. Ahmed

Dept. of Phys. Univ. of Maryland

F. Benmokhtar, T. Horn

Dept. of Phys. Southern Univ. at New Orleans

M. Elaasar

Phys. and Astro. Dept. California State Univ.

Ed F. Gibson

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Introduction

p-shell nuclei : 6,7Li, 10,11B, 12C, (H2O for calibration)~ Fine structure ; core excited states etc. Baryon-baryon interaction in SU(3), charge symmetry breaking, coupling in large isospin hypernuclei cluster structure etc.

fp-shell nuclei : 40Ca(PR08-002), 51V, 52CrBeyond fp-shell : 89Y

~ Single-particle potential Distinguishability of a hyperon

U0(r), m*(r), ..

E05-115 : Λ Hypernuclear Spectroscopy

in the wide mass region 　

Layout of HKS-HES system in Hall-C

HKS

HES

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Setup of the 3rd generation experiment

HES (e’ arm) HKS (K arm)

Magnet Configuration Q-Q-D Q-Q-D

Central Momentum 0.55~1.0 GeV/c 1.2 GeV/c

Momentum Acceptance ±0.1 GeV/c ±0.15 GeV/c

Solid Angle 10 msr 8 msr

Resolution (FWHM) 2.0×10-4 2.0×10-4

Newly constructed

Etop1pass

(GeV)

Etop2pass

(GeV)

10.40.3 0.6 0.8

Ee’ (GeV)

2.51.8 1.9Ee at Hall-C

(GeV)

Acceptable Central Energy

(GeV)

HESENGE

2.0 2.2 2.4

4.4 4.55 5.0 6.0

9.45 10.3 10.8 12.0

2.1

Comparison of available beam energy betweenHKS+ENGE and HKS+HES

(2nd gen.)(3rd gen.)

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e’ from Bremss.

Moeller ring

e’ associatesWith virtual photon

Background

Signale’

Beam 　（ 1.8GeV ） Target e’-arm rate

1st Exp. (w/o tilt) 0.67 A 12C, 22 mg/cm2 200 MHz

2nd Exp. (w/ tilt) 30 A 12C, 100 mg/cm2 1 MHz

How to avoid background electrons ~Tilt Method~

Backgrounds on e’ arm : e’ from Bremss. & Moeller

→Tilt Method

x’

y’

2.5GeV 　 Electron Beam Energy

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Acceptance of HESVirtual Photon Energy 　 1.5 GeV

Brems

Moller

Enge acceptance

x’

y’

2nd gen. (E01-011)

Enge 　 0.3 GeV/c

Beam Energy 　 1.8 GeV

HES acceptance

3rd gen. (E05-115)

HES 　 1.0 GeV/c

Beam Energy 　 2.5 GeV

×10

10 times virtual photon tagging efficiencyx’

y’

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HES detectors

e’

ED

EDC1

EHODO1,2

Detector Specifications

EDC1 (used in the 2nd Exp.)

Effective area 100W[cm] *12H[cm] *32T[cm]

Layers 10 (xx’, uu’, xx’, vv’, xx’)

Layer distance 7.5[cm]

Cell Size 0.5cm

EDC2 (same type as HKS DC) ; Hampton Univ.

Effective area 105W[cm] *30H[cm] *3.5T[cm]

Layers 6 (xx’, uu’, vv’)

Drift Distance 6.35mm

EHODO1 ; Tohoku U. 29 segments plastic scinti.

EHODO2 ; Tohoku U. 29 segments plastic scinti.

Position Detectors EDC1 （ Honeycomb type ） + EDC2 （ Planer type ）Trigger Counters EHODO1 　 + 　 EHODO2

EDC2

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Upgrade of HKS Detector package

• Renew boxes of Water Cherenkov （ Tohoku U.)– Improved light collection efficiency

• Add Lucite Cherenkov (Hampton U.)– Additional information on PID and TOF measurements

• Add bucking coil for Aerogel Cherenkov (Florida Int’l U.)– Cancel stray field of HKS dipole (~ 5 gauss) to recover gain of PMT

LC

RenewBucking Coil

Q-Q-D

Add

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Yield Estimation

Target

（ 100mg/cm2 ）

Yield for 100nb/sr [/hour]

E01-011 （ 1.8GeV, 24

A ）E05-115 （ 2.5GeV, 30

A)

7Li ( 15A ) 9 48

10B 10 67

12C 10 56

40Ca ― 17

51V ― 13

89Y ― 7.5

about 5 times

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Simulated spectrum of 51V(e,e’K+)51Ti

HKS (8msr ) + HES⊿E = 300 keV [FWHM]Beam I = 30 [μA]V 100 [mg/cm2] S/N=5

Exp

ecte

d C

ou

nts

/100K

eV

/144h

- BΛ ( MeV )

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Pictures @ TOKIN (Sendai, Japan)

CEBAF　2.5GeV　Electron　Beam

SplitterSplitter

1.0GeV/c e’

1.2GeV/c K+

HESHESHESHES

HKSHKSHKSHKS

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Splitter Magnet

1.72 m

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Q-Q-D Magnet

EQ1EQ2

ED

EQ1EQ2

1.25 m

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Q-Q-D MagnetTilt Version

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Schedule

• Dec 2007 HES departed from Japan

• Feb 2008 HES arrives at Norfolk

• Mar 2008 Test experiment of detectors

at Tohoku Univ. (LNS)

• Apr 2008 Tohoku group begins stay at

JLab

By the end of 2008

Ready to install HES in Hall C

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Summary

• HES magnets are on the way to JLab

• HES detectors are under construction

• Part of HKS detectors, WC and AC will be

upgraded and LC will be added

• Yield is 5 times larger than the 2nd generation exp.

• Will be ready to install HES by the end of 2008

Various targetsVarious targetsE01-011　First　GenerationE94-107　Hall　A　ExperimentE01-011　Second　GenerationE05-115　Third　Generation

PR08-002　Third　Generation

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HES-HKS momentum acceptance

51Ti g.s

HKS

HES

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E01-011 Set Up