Rare Isotope Science Project in Korea:
RAON and nuclear theory
Youngman Kim
Rare Isotope Science Project (RISP)
Institute for Basic Science (IBS)
ECT*-APCTP workshop (Sept.14-18)
Outline
• RISP in Korea
• Theory activities at RISP
RAON Site
~11 km
Current RISP Office
Area (Lot/Bldg): 952,066 m2 / 130,257 m2
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RAON Concept
 High intensity RI beams by ISOL & IF
20m
ISOL : direct fission of 238U by 70MeV proton
IF by 200MeV/u, 8.3pμA 238U
ECR-IS (10keV/u, 12 pμA)
LEBT
RFQ (300keV/u, 9.5 pμA)
MEBT
128.5m
 High quality neutron-rich RI beams
132Sn
100m
with up to ~250MeV/u, up to ~108 pps
 More exotic RI beams by ISOL+IF
SCL1 (18.5 MeV/u, 9.5 pμA)
Driver LINAC
Chg. Stripper
375m
70m
SCL2 (200 MeV/u, 8.3 pμA for U+79)
(600MeV, 660 μA for p)
20m
MEBT
250m
RFQ
CB
SCL3
ECR-IS
100m
Post Accelerator
Low Energy Experiments
Nuclear Astrophysics
100m
HRMS
μSR,
IF Target
Bio-medical
RF Cooler
Cyclotron
(p, 70 MeV, 1mA)
High-precision
Mass Measurement
Gas Catcher IF Separator
110m
CB : Charge Breeder
HRMS : High Resolution Mass Separator
6
80m
ISOL
Target
High Energy Experiments
Nuclear Structure/
Symmetry Energy
KOBRA
(KOrea Broad acceptance Recoil spectrometer and Apparatus)
Main facility for nuclear structure and nuclear astrophysics studies
with low-energy stable and rare isotope beams
 Main Research Subject :
1) Nuclear structure of exotic nuclei near the drip lines
2) Astrophysically important nuclear reactions
3) Rare event study - Super Heavy Element (SHE), New isotopes
4) Nuclear physics with polarized beam/target etc
- Main Specification
Stage 1
Wien
filter
Stage 2
Big-bite
Spectrometer
Wien
filter
F3
F1
F2
In-flight separation
or
Beam transport
F0
* Design Concept
1) Two stage
F5
F4
* Associate equipments
FP
Equipments
F0
RI production target,
F3
gas-jet target, gamma-array,
detection system, b-NMR
F5
Focal plane detection system
- RIBs production
via low-E in-flight
method by multi
nucleon trasfer
reaction (ex. 44Ti)
- Stage 1 (F0~F3) :
Production and separation of RIBs
via In-Flight method with high
intensity
SIBs from SCL
Maximum magnetic rigidity (Tm)
~3
Mass resolution (m/Δm) @ stage 1
~700
Dispersion (cm/%) @ stage 1
4.2
Momentum acceptance (%) @ stage 1
±4
Angular acceptance (mrad) @ stage 2
40 (H) and 200 (V)
- Ion optics calculation was done using K-trace code (ray tracing)
- Rotation of ‘stage 2’, variable position of Q-magnets in ‘stage 2’
are under consideration
- Technical design is in progress
- Design of associate equipment
- Stage 2 (F3~F5) :
Big-bite spectrometer with Wien filter
 large acceptance
[Gas-jet target]
[PPAC]
[Gamma array]
LAMPS
(Large Acceptance Multi-Purpose Spectrometer)
Main facility for nuclear matter and nuclear reaction studies
with intermediate energy stable and rare isotope beams
Main Research Subject:
Study of nuclear symmetry energy at supra-saturation density
via heavy-ion collision experiment
L.W. Chen et al.,
PRL 94, 032701 (2005)
Asy-soft
• Beam Energy: up to 250 MeV/u
• Solenoid Spectrometer
- Max. 1T solenoid magnet
- TPC (~ 3 sr acceptance,
charged particle tracking)
- Scintillation counter (trigger & ToF)
- Si-CsI (measure heavy fragment
using E-E method)
• Dipole Spectrometer
- Rotatable dipole magnet and
focal plane detector
(capable to study nuclear reaction)
• Neutron Wall (neutron tracking)
RISP Milestone Schedule
ECR SI Beam
RFQ Beam SCL Demo Beam
SCL SI Beam
IF RI Beam
ISOL SI Beam
Cyclotron
ISOL RI Beam
DAY-1 Experiment
Start Utility Supply
Begin Construction
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Completion
Theory activities at RISP;
through international/domestic collaborations!
•
•
•
•
•
Boundaries of the nuclear landscape
– Covariant density functional theory (Shuangquan Zhang) ...
Production of exotic nuclei and heavy elements
– Reaction models (DNS, …), reactions for astrophysics
Equation of state of dense matter
– New vibrational modes and asymmetric matter (Panagiota Papakons
tantinou) ...
– Symmetry energy of dense matter … (Mannque Rho, Friday)
Neutron stars (Chang-Hwan Lee, Thursday)
Nuclear structure and reactions from first principles
– Ab initio NCSM ...
– Unitarily transformed realistic interactions (Panagiota
Papakonstantinou)
•
Nuclear transport: quantum molecular dynamics, RBUU (Yujeong
•
chiral effective field theory, …
Lee, Thursday)
Asymmetric matter in a parity doublet model
Introduce two nucleon fields that transform in a mirror way under chiral transformations:
“Linear sigma model with parity doubling,” C. E. DeTar and T. Kunihiro, Phys. Rev. D
39, 2805 (1989)
The state N+ is the nucleon N(938). while N- is its parity partner conventionally
identified with N(1500).
Cf.
Parity doublet model with HLS
Motivation:
 Lower m0 ?
 Non-zero isospin density (chemical potential)
 Lower Tc for (chiral) transitions?
Y. Motohiro, YK, M. Harada, PRC 92, 025201 (2015)
slope parameter
S0=31 MeV
Phase diagrams for m0 = 900 MeV
solid: first-order,
dashed: crossover
point: critical point (second order)
LGT: 1st 2nd
Critical chemical potential
drops a bit
Phase diagrams for m0 = 500 MeV
smaller m0 favors
smaller critical density for
chiral phase transition
both in symmetric and asymmetric
dense matter
Quantum Molecular Dynamics
Transport model : Model to treat non-equilibrium aspects of the
temporal evolution of a collision.
 Many-body problem with nucleons
 Numerical simulation (event generator)
 Different methods for different energies
Kyungil Kim (RISP), K. S. Lee (CNU), etc
~10-20 sec
Non-equilibrium aspects
Time
~10-16 sec
Equilibrated (decay statistically)
n
p
α
Transport model
QMD
BUU
Other model
HIPSE
DIT
…
Statistical Model
GEMINI
SIMON
EMPIRE
…
Initialization
<Gaussian distribution>
σr, σp : widths in configuration and momentum
spaces, respectively
d > 1.5 fm
<Density distribution>
- Wood-Saxon function
<Fermi momentum>
<Momentum of a nucleon> <Pauli principle>
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Propagation
Skyrme parametrization for NN potential
Ref.) M. Papa PRC 64(2010)024612
<Equation of Motion>
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Stability
9Be
40Ca
<Propagation with stabilized nuclei>
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N-N Collision
In classical scattering,
r1
b
𝜎 = π 𝑟1 + 𝑟2
r2
2
𝑏 < 𝑟1 + 𝑟2
Two particles are always scattered.
In our model,
If a distance, d, between two nucleons is smaller than b,
d<b, there is always a collision try.
Here, 𝝈𝒕𝒐𝒕 is in-medium cross-section.
Ref.) G.Li and R.Machleidt PRC 48, 1702, PRC 49, 566
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Pauli blocking
<x-space>
<p-space>
<Phase space density for i th particle>
Occupation number
After a nucleon-nucleon collision , we calculate the 6dim. phase space density for each nucleon. If this
condition for any nucleon is not satisfied, that collision
will be blocked by the Pauli principle.
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Central and Peripheral Collisions
b=0 fm
b=7 fm
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Ab initio No Core Shell Model
• Ab initio: nuclei from first principles using
fundamental/realistic interactions without
uncontrolled approximations.
• No core: all nucleons are active, no inert core.
• Shell model: harmonic oscillator basis
• Point nucleons
Ab initio No Core Gamow Shell Model
Ab initio method and NN interaction
• Unfortunately, the NN interaction at low energies needed for
nuclear physics applications cannot be directly derived from
QCD at the moment
• Ab initio theory requires, of course, a realistic NN interaction
accurately describing NN scattering data and deuteron
properties
• We use NNLOOPT and JISP16 in this study
6Li
in ab initio No Core Shell Model: NCFC approach
NCFC model is a version of the ab initio no core shell model (NCSM)
with a few important characteristics:
(1) the use of interactions defined for an infinite Hilbert space,
(2) extrapolating to the continuum limit (infinite matrix limit)
(3) uncertainty estimation for the extrapolation.
In collaboration with:
Ik Jae Shin (RISP, IBS)
James Vary, Pieter Maris (Iowa State U.)
Christian Forssen (Chalmers U.), Jimmy Rotureau (FRIB, MSU)
converge more slowly,
underbound by 1.44 MeV
,
underbound only by 0.46 MeV
Both are within 2% of the experimental value
reasonable converged, about 3-5% higher than experiments
Results from Ab initio No Core GSM
Energy of the ground state
Energy of a resonance state (2+, 1)
Imaginary part of the energy of (2+, 1) state
JISP16 vs Daejeon16
ISTP
(inverse scattering tridiagonal potential)
N3LO interaction
SRG
(similarity renormalization group)
SRG-evolved N3LO
PET (phase equivalent transformation)
JISP16
(J-matrix inverse scattering potential)
Daejeon16
Ik Jae Shin (RISP, IBS), Andrey Shirokov (Moscow State U.)
James Vary (Iowa State U.), et al, in preparation
6Li
g.s. energy
• The results of stable nuclei seem to be improved.
N3LO-SRG
N3LO-SRG-PET (Daejeon16)
experimental value : -31.995 MeV
8He
g.s. energy
• Daejeon16 also gives reliable results even though for exotic nuclei.
N3LO-SRG
N3LO-SRG-PET (Daejeon16)
experimental value : -31.409 MeV
Thank you for your attention !
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