Plan for Symmetry Energy Experiment at RAON

Byungsik Hong(Korea University)

Heavy-Ion Meeting (HIM2013-05)Korea University, Seoul, Korea, May 24, 2013

24 May, 2013 HIM2013-05 1

Outline1. Brief introduction to RISP− Rare Isotope Science Project in Korea RIB accelerator RAON Various experimental facilities

2. KOBRA− Broad acceptance recoil spectrometer at low-

energy experimental hall3. LAMPS− Large-acceptance multipurpose spectrometer

at low- & high-energy experimental halls4. Summary

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RAON

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Accelerator Driver Linac Post Acc. Cyclotron

Particle proton U+78 RI beam proton

Beam energy 600 MeV 200 MeV/u 18.5 MeV/u 70 MeV

Beam current 660 μA 8.3 pμA - 1 mA

Power on target 400 kW 400 kW - 70 kW

ECR-IS (10keV/u,12 pμA)LEBT

RFQ (300keV/u, 9.5 pμA)

MEBT

SCL1 (18.5MeV/u, 9.5 pμA)

SCL2 (200MeV/u, 8.3 pμA for U+78)(600MeV, 660 μA for p)

SCL3 (18.5MeV/u)

ECR-IS

RFQ

MEBT CB

HRMS

RFCooler

ISOLTarget

IF Target

Fragment Separator

ChargeStripper

Driver LINAC

Post Accelerator

IF system

ISOL system

μSRMedical research

Atom/Ion Trap

Cyclotron (p, 70 MeV, 1 mA)

Low-Energy Experimental

Area High-Energy Experimental Area

Research Topics

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Nuclear Physics Exotic nuclei near the neutron drip line Equation-of-state (EoS) of nuclear matter

Material science Production & Characterization of new materials -NMR / SR

Nuclear Astrophysics Origin of nuclei Neutron stars and supernovae Nucleosynthesis Superheavies

Medical & Biosciences Advanced therapy technology Mutation of DNA New isotopes for imaging

Nuclear data with fast neutrons

Basic nuclear reaction data for future nuclear energy

Nuclear waste transmutation

Atomic/Particle Physics Atomic trap Fundamental symmetries

RIS

P

Research Topics

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Nuclear Physics Exotic nuclei near the neutron drip line Equation-of-state (EoS) of nuclear matter

Nuclear Astrophysics Origin of nuclei Neutron stars and supernovae Nucleosynthesis Superheavies

RIS

P

In this talk

KOBRA

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F1

F2

F3

F4 F5

D1 D2

D3

W1

W2

F0

Korea Broad Acceptance Recoil Spectrometer

and Apparatusat low-energy

experimental area

Stage 1

Stage 2 High-performance spectrometer with detection system

Main experimental facility for nuclear science with low-energy beams up to 18.5 MeV/u

KOBRA

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F1

F2

F3

F4 F5

D1 D2

D3

W1

W2

F0 SCL1

SCL2

SCL3

ECR

ECR

ISOL

Stable ion beamsvia SCL1 or SCL3

RIB via ISOL+SCL3RI production target at F0

Gas-jet target -array

detection system at F3

Focal plane detection system

at F5

Stage 1 (F0~F3): Production and separation of RIBs by in-flight method with high-intensity stable ion beams from ECR & LINAC

Experimental target at F3 (enough space for ~3 m): In-beam -ray spectroscopy, Symmetry energy & charged particle spectroscopy, Super-heavy element, Spin dependence, etc.

Stage 2 (F3~F5): Big-bite spectrometer with Wien filter

KOBRA

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F1

F2

F3

F4 F5

D1 D2

D3

W1

W2

F0

Stage 1: In-flight SeparatorF0~F3

{QQDQQ-QQDQQ-QQWQQ}

Stage 2: Large-Acceptance Spectrometer F3~F5

{QQWQQ-QQD}

Maximum magnetic rigidityMass resolution (M/M)DispersionMomentum acceptance @ stage1Angular acceptance @ stage2

~3 T∙m< 200

~2 cm/%14%

40 mrad (H)200 mrad (V)

D1 & D2: Gap 20 cm/Radius 1.5 m/Deflection angle 45º D3: Gap 20 cm/Radius 1.5 m/Deflection angle 60º

W1: Length 2 m/E. gap 20 cm/±300 kV W2: Length 4 m/E. gap 20 cm/±300 kV

F0, F2, F3 & F4: Achromatic focusingF1: Dispersive focus (D=2.03 cm/%)F5: Dispersive focus (D=2.05 cm/%)

Available Beams for KOBRA1. In-flight mode

– p-rich RIB up to A~80(cannot be produced via U fission)

– Intensity > 106 pps, Purity ~100%2. ISOL mode

– p-rich RIB useful for radiative capture reactions– n-rich RIB with A=80~140 useful for the transfer reactions

in r-process 3. Stable Ion Beams

– 64Ni & 58Fe are useful for hot fusion reactions– Actinide target to produce Z=116~122– Examples: 58Fe+232Th → 290-x116 + xn, 64Ni+232Th → 296-x118 +xn,

58Fe+244Pu→ 299120 + 3n, 64Ni+238U→ 299120 + 3n– Gas-filled or vacuum mode

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KOBRA: Science Program1. Nuclear structure

– Comparison of the nuclear structures for the isobaric mirror nuclei at drip lines (charge symmetry and independence)

– Resonant conditions of unbound nuclear states– Spin dependence of basic properties

2. Nuclear astrophysics– Capture reactions: (p,), (,), (n,)– Resonant scattering: p and resonant elastic scattering– Transfer reactions: (d,p), (,p), etc.

3. Rare events– Super-heavy elements– Decay spectroscopy

4. Nuclear symmetry energy– Pygmy dipole resonance (PDR)/Giant dipole resonance(GDR)– Charged particle and neutron production in central collisions

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KOBRA: Science Program

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178ErTmYbLuHfTaWReOsIrPtAuHgTl

126120N

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s-process

Sn + Pb => W132 208 200126

Xe + Pb => Yb144 208 196126

Sn + Pb => Pt132 208 210132

Xe + Pb => Pt144 208 220142

at E = 10A MeV

at E = 200A MeV

New neutron-rich heavy nuclei“High Intensity Stable Beams in Europe”

NUPECC Report (July 2007)

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25Al

24Mg

23Na

22Ne21Ne20Ne

22Na

23Mg

24Al

21Na

22Mg

19F

18O

21Mg

20Na

19Ne

18F

17O

18Ne

17F

16O

15N

15O14O

13N

12C 13C

14N

Stable

Unstable

CNO cycle : T9 < 0.2 HCNO cycle: 0.2 < T9 < 0.5rp-process : T9 > 0.5

Hot-CNO ICNO cycle

Hot-CNO IIrp-process

Breakout paths to rp-process

15O()19Ne Reaction Experimental requirements for

direct measurement of − Beam intensity (15O) > 1010 pps− Target density (4He) > 1018/cm2

− Recoil det. efficiency > 40%⇒ >1 Count/hr

Nova models in nuclear astrophysics

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44Ti(p)47V Reaction

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The et al., Astrophys. J. 504 (1998)

44Ti(p)47V Reaction

Presently, TRIUMF, CERN, CNS CRIB are working on this reaction.

At RISP, the direct measurement will be possible with an active target in the IF mode of KOBRA.

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F3

F4 F5

D1 D2

D3

W1

W2

F0

Symmetry Energy at KOBRA

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Low-energy LAMPS

Si-CsI Neutron Array

Equation of State (EoS) and Symmetry Energy

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Energy of nuclear matter, / , 0 ⋯

where and

Useful expansion of around

where

3 (slope)

9 (curvature)

Equation of State and Symmetry Energy

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)(ρsymE/(M

eV)

(fm-3)CDR, FAIR (2001)

L.W. Chen, C.M. Ko, B.A. Li, Phys. Rev. Lett. 94, 032701 (2005)

Symmetry Energy

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A.W. Steiner, M. Prakash, J.M. Lattimer and P.J. Ellis, Physics Report 411, 325 (2005)

RIB can provide crucial inputEffective field theory, QCD

Symmetry Energy & Neutron Stars

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Neutron star stability against gravitational collapse Determine stellar density profile and internal structure Observational consequences

− Cooling rates of proto-neutron stars − Stellar masses, radii & moment of inertia from temperatures

& luminosities of X-ray bursters M vs. R relationship

− Uncertainty of softness of EOS and influence of

Important to provide complementary laboratory constraints at specific densities

P. Krastev, B.A. Li, and A. Worley, Astrophys. J. 676, 1170 (2008)

Static

Keplerian

Experimental Observables

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1. Particle ratios of mirror nuclei and pions− n/p, 3H/3He, 7Li/7Be, -/+, etc.

2. Collective flow− Directed (or side) and elliptic flow parameters of

n, p, and heavier fragments

3. Pygmy dipole resonance− Energy spectra of gammas− Sizes of n-skins for unstable nuclei

4. Various isospin-dependent phenomena− Isospin fractionation and isoscaling in nuclear

multifragmentation− Isospin diffusion (transport)

PDR at KOBRA

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P. Adrich et al., PRL 95, 132501 (2005) Coulomb excitation of neutron-rich 130,132Sn isotopes reveals a peak at ~10 MeV, which is absent for stable isotopes.

Consistent with low-lying electric dipole strength.

These results can be interpreted as an oscillation of a neutron skin relative to the core.

Experimental Requirements

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1. We need to accommodate– Large acceptance– Precise measurement of momentum (or energy)

for variety of particle species, including +/- and neutrons, with high efficiency

– Gamma detection for PDR– Keep flexibility for other physics topics

2. This leads to the design of LAMPS– Large-acceptance Multipurpose Spectrometer– Low-energy version to be built at F3 of KOBRA– Full version LAMPS at the high-energy

experimental area

LAMPS

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Central and peripheral collisions 132Sn+112Sn, 132Sn+118Sn, 132Sn+124Sn 124Sn+112Sn, 124Sn+118Sn, 124Sn+124Sn 112Sn+112Sn, 112Sn+118Sn, 112Sn+124Sn 106Sn+112Sn, 106Sn+118Sn, 106Sn+124Sn

etc.

Time Projection Chamber

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Simulation with triple GEM readouts at both ends by Garfield++− Gas mixture: Ar 90%+CO2 10%, Voltage for each foil: 450 V− <Gain> ~ 1.4Χ106, <Drift velocity> ~ 50 m/sec− <Dispersion> after 60 cm (maximum drift distance) < 3 mm

300 mm

900 mm

500 mm

400 mm53.1° 24.0°

=-0.7 (127o) =1.6 (24o)

Beam

150 mm

Target

Genie Jhang(Korea Univ.)

Time Projection Chamber

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Central Au+Au at 250 AMeV(IQMD)

Genie Jhang (Korea Univ.)

Color scale: the number of electrons in each pad

Pad− Shape: hexagonal− Total number

90,000 for 2.5 mm20,000 for 5 mm

Signal processing− GET: General

Electronics for TPC 2.5 mm

Si-CsI

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1.6 < < 2.1(14o < Lab < 24o)

Suhyun Lee & Songkyo Lee(Korea Univ.)

Si-CsI

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Suhyun Lee & Songkyo Lee(Korea Univ.)

E=E1+E2+E3Etot=E+Ec

E=E1+E2+E3 is preferred at high energies

E=E1 is preferred at low energies

Neutron Detector Array

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Kisoo Lee & Eunah Joo (Korea Univ.)

veto

Cross section of each bar:10Χ10 cm2

Construction of the prototype and test with radiation sources− Dimension: 0.1Χ0.1Χ1.0 m3

− Sources: 60Co and 257Cf − Time resolution: 488 ps, Position resolution: ~8 cm for CFD

Neutron Detector Array

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Kisoo Lee & Benard Mulilo (Korea Univ.)

257Cf

Watt spectrum: ⁄ ∝ sinhwith =0.88 MeV-1 and =2.0 MeV-1

Ref) B. Watt, Physical Review 87, 1037 (1952)

Dipole Spectrometer

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Songkyo Lee (Korea Univ.)Chong Cheoul Yun (IBS)

Ion optics calculation by the matrix method

(GICOSY code)

Dipole Spectrometer

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Songkyo Lee (Korea Univ.) & Chong Cheoul Yun (IBS)

Large angular acceptance75 mrad (H)100 mrad (V)

Coulomb Breakup

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NeutronDetector

Array

Dipole Spectrometer-Array

- PDR/GDR measurements124,130,132Sn+208Pb, 68,70,72Ni+208Pb, 50,54,60Ca+208Pb, etc.

- Photoabsorption measurementsVarious 1n and 2n removal cross sections for unstable nuclei

- Measurement of E* from gamma, beam fragment, and neutron(s)

Summary1. RAON

– First large-scale facility for nuclear physics in Korea2. KOBRA

– Broad acceptance recoil spectrometer at low-energy experimental area

– To cover nuclear structure, nuclear astrophysics, super-heavy elements, and nuclear symmetry energy

3. LAMPS– Large-acceptance multipurpose spectrometer at high-

energy experimental area (Low-energy version of LAMPS at KOBRA)

– Primary purpose is to measure the nuclear symmetry energy at sub- and supra-saturation densities

– Useful also to study various photoabsorption processes

Stay tuned!24 May, 2013 HIM2013-05 33