H. Sakurai

RIKEN Nishina Center for Accelerator-Based Science

Challenges for the r-process and EOS

Congratulations!

Establishment ofJapan Forum of Nuclear Astrophysics (JFNA)

1st Workshop organized by JFNA

RIPSGARIS

60~100 MeV/nucleon

CRIB (CNS)

~5 MeV/nucleon

350-400 MeV/nucleon

Old facility

New facility

RIKEN RI Beam Factory (RIBF)

BigRIPS

SRC

RILAC

AVF

RRCfRC

IRC

Experiment facility

Accelerator

SHARAQ

SAMURAI

ZeroDegree

SLOWRI

SCRIT

RI-ring

SHE (eg. Z=113)

Intense (80 kW max.) H.I. beams (up to U) of 345AMeV at SRCFast RI beams by projectile fragmentation and U-fission at BigRIPSOperation since 2007

To be fundedIn phase II

RIPS (RIKEN Projectile-fragment Separator)

Primary beam

RI beam

R I pro ductiontarge t

W e dgeEn ergy -deg rade r

S lit

S lit

required for secondary nuclear reactionslarge momentum acceptance,

solid angle and high magnetic rigidity

Second-generation PF separatorIntense RI beams

T.Kubo et al. NIMB70, 309(92)

Challenge in methodologyInvariant mass spectroscopy

for particle unbound statesIntermediate energy Coulomb excitation

for B(E2)　etc...

optimized for PF reaction

Progress of Research Opportunities with RI Beams Construction of a dedicated facility for RI beam productionvia the projectile fragmentation

0th-generation at LBL 1st-generation at LISE-GANIL

1990-

Challenges in Methodology with fast RI beams at RIPS

transmission method for nuclear radii information energy-dependence of total reaction cross sections, e.g. 11Bein-beam gamma spectroscopy for particle bound states Magicity loss at N=20 Anomaly of B(E2) in 16C via Coulomb excitation, (p,p’), Two-step fragmentation, Recoil-shadow methods, ...invariant mass spectroscopy for particle unbound states Large B(E1) in the halo nuclei 11Be, 19C Radiative capture cross sections in stellar evolutions :7Be(p,)8Bmissing mass spectroscopy Spectroscopy on the heaviest hydrogen 7Hpolarized rare-isotope beams for electro-magnetic moments Anomaly of quadrupole moments in the B isotopes via beta-NMR techniques

~40-70 A MeV and A < 60

New frameworks for the new region of nuclear chart

neutron-halo nuclei

neutron-skin nuclei

1s1/ 2

1p3/ 21p1/ 2

1d5/ 22s1/ 21d3/ 2

1f7/ 2

2p3/ 21f5/ 22p1/ 21g9/ 2

2

8

20

28

50

82

1g7/ 22d5/ 22d3/ 23s1/ 21h11/ 2

Stable Nuclei Neutron-rich Nuclei

N=6

N=16

?

?

11Be, 11Li, 19C...

?

To write up new text book ： Exotic phenomena, Systematics, etc. Isospin-, density-dependences of effective interactions, nucleon-corrections Microscopic system (nuclei) to Macroscopic system (neutron stars)

Nuclear Matter: New formsNuclear Structure: Shell evolution

Synthesis up to U （ r-process ）　　 unknown neutron-rich nuclei　 theoretical predictions only

Necessary of experimental investigation for nuclear properties of heavy and neutron-rich nucleiMass, life-time, decay mode

Challenge for r-process path and explosion in supernovae

5

Explosion mechanism of supernova　　 No explosion in theoretical works　　 Outer clast of neutron star

Necessary of experimental study for Equation-of-State for nuclear matter

Mass number

1987A

Challenge to investigate EOS of neutron matter

(fm-3)

Normal density

E/A

[MeV

]

3NF　 T=3/2 channels?　 density dependence?

1S correlation BCS-BEC crossover in dilute system ( ~ 0.10) ?

3P2 correlation　　 pairing gap? Density depencence?

from nuclei to neutron starsB. A. Brown, PRL85 (2000) 5296

Role of di-neutron in skin? : collectivity, transfer reactions

Elastic d+p for T=1/2 Nuclear structure in very neutron-rich nuclei for T=3/2?Heavy-ion Collisions to achieve ~2-30 ?

????

RI beam production via in-flight method

Heavy ion accelerator

（ to collect and separate RI with analyzing magnets ）

RI production

RI beam

target

（ to accelerate nuclei ）

RI beam separator

Yield rate of 78Ni via fission isabout 1 ､ 000 times higher thanvia fragmentation.

78Ni

N=50

10,000:1

Fission reaction via 238U beam

Fragmentation reaction via 86Kr beam

Proton number

Pro

babi

lity

（ to make reactions　 Be, C, etc ）

Advantage of fission via U beam

Dec. 2005

Super-conducting Ring Cyclotron（ SRC）

Cyclotron accelerator　　－＞ beam intensity is very highAcceleration of U up to 70% of speed of light　　－＞ thick target can be used－＞ world-highest intensity for RI beam

Total weight 8300 tonHighest bending power （ 8Tm)Maximum magnetic field 3.8 T

SRC

RIBFAcceleration

performance AVF AVF+RRC+SRC for m/q=2 inc. pol. d

SRC

IRC

I = 1 p (goal)

With fRC (SRC) 350 MeV/u U88++ (8Tm)

With fRC (IRC)

Performance of RIKEN Accelerator Complex

BigRIPS

RI beam separator 　 BigRIPS

SRC

Nov. 2006 completed

Large acceptance for fission fragment 50%　　 superconducting quadrupole magnetsHigh transmission for RI beamsTandem-type separator with two stages

Beam from SRCNC dipole mag.

Productiontarget

RI beam

8

SC quadrupole mag.

First stage

Second stage

Total dose: 3.6×1012

New isotopes of 125, 126Pd

238U + Be(7mm) at 345 MeV/u

2007 MAY-JUNE

Isomer 96RbBρ: 7.438 Tm, ΔP/P=2%

T. Onishi et al, JPSJ 77 (08)083201.

Identification of new isotopes 125,126Pd

A/Q resolution(r.m.s): 0.041% at Z=46 B resolution (r.m.s): 0.02%

Cf. 124Pd 19 counts, 125Pd(cand.) 1count at GSI, 1997 PLB 415, 111 (97); total dose ~1x1012

126 (3counts)

T. Onishi et al, JPSJ 77 (08)083201.

Great expansion of nuclear world by RIBFIntensity > 1 particle/day

(EPAX@GSI)

Projectile Fragmentation

In-flight U fission & P.F.

prot

ons

neutrons

78Ni ~0.1 particles/sec. (2007) by 10pnA 350 MeV/u U-beam

New Element27811304 July 23 18:5557 fb

10 particles/sec. (goal) by 1pA

Exploration of the Limit of Existence

BigRIPS Fragment Separator high acceptance for fission fragments pid for RI beams at the second section

ZeroDegree Multi-function BT line pid for ejectiles in inclusive- and semi-exclusive measurement medium resolution (p/dp ~ 2000 – 4000)

Experimental set-ups

BigRIPS /ZeroDegreeExploration into “Isospin Frontier” toward the drip-linesReaction study fit for high energy domain 200-300A MeV

RIB productionPID section

BigRIPS in-flight production of fast rare-isotope beams Ground state properties and low lying excited states

via decay spectroscopy / transmission method: particle stability, T1/2, Q, R, Ex.(2+)... Deeply bound pionic states via (d, 3He) at 500 MeV Three-body force via pol. d+p elastic scattering at 700 MeV

ZeroDegree multi-function beam line for inclusive/semi-inclusive measurements 　　 production of 3rd RI beamsCollectivity and matter distribution

via in-beam gamma / missing mass spectroscopy One step energy regime 200~300 A MeV B(E2), B(M1), (p,p), (p,p’), Ex.... Iso-diffusion

Phase-I programs at BigRIPS/ZeroDegree 2007~

Rare-Isotope Physics Programs Fast RI beam production to search for new isotopes Global survey to search for anomalous regionsSpecific programs with deuteron beams

Flag ship regions at neutron-rich side

238U beam

48Ca beam

Neutron drip-line for F-to-Mg isotopes? Particle stability 33F, 36Ne, 39Na, 42Mg p-wave halo ? : 31Ne ...Island of inversion : deformation center at N=22? B(E2) for 30Ne and 36Mg, etc.Possible deformation at N=28? B(E2) and Ex(2+) for 42Si, 38Mg, etc.Oxygen beyond N=16 Ground and excited states for 25, 26O

New isotopes between Z=20 to 60 Maaaany new ones !!R-process path T1/2 at A>80New magicity at 54Ca ?? B(E2), Ex(2+), ...Magicity loss at 78Ni ?? T1/2, B(E2), Ex(2+), ...Magicity at N=82 ?? B(E2), Ex(2+), ...Deformation at A~110 ?? collective states

Half-lives of nuclei beyond 78Ni at RIBF

P.T.H, PRL 94, 112501(2005) 78Ni ~10 particles/week at MSU

Magicity at Z=28 and N=50 ?

Z=28 N=50

79Ni at RIBF 77Co at RIBF

more accurate measurement for 78Ni at RIBF78Ni ~20 particles/day at RIBF at present

50

50

82

82

126

2820

20

B(E2)-1 [1/W.u]

neutron number

prot

on n

umbe

r

132Sn

208Pb

78Ni double magicity?

N=34 new magicity?N=28 magicity?

N=82 magicity?

deformation region?48Ni double magicity?

100Sn double magicity?

Large Room for B(E2)

2001

R&D: Detectors/Targets for Phase-I programs

Particle identification and beam monitoring at high rate Gas counters with high rate capability at ~106 /sec delay-line PPAC and MUSIC

Targets Liquid hydrogen/helium targets for in-beam gamma and invariant mass

thickness 100-250 mg/cm2

Window-less solid hydrogen target for missing mass (p,p), (p,p’) thickness 3mm -> 1mm (goal) Polarized proton target

Gamma detectors for fast RI beams (v/c ~ 0.6) DALI-2 NaI-based ball 19% eff. for 1MeV gamma, 12% resolution GRAPE Ge-based ball 3% eff. for 1MeV gamma, 1.5% resolution

beta-spectroscopy Cylindrical active implantation target dedicated to half-life measurements Double-sided silicon strip detectors as active implantations

missing mass spectroscopy Recoiled-out proton detectors for proton elastic scattering Spectrometer for recoiled-out protons emitted at 0 degree MUST2

Others needed additionally

Position sensitive detectors for low-E neutrons for (p,n)

Faster Beam-line detectors for more intense RIBThinner Beam-line detectors for heavy RIBBetter resolution detectors for E of RIB

Faster DAQSecond Level TriggerMulti-Trigger Control System

3H target for (t,p) ?neutron target for (n,gamma) ?

SAMURAI - large acceptance Kobayashi et al. in 2011

SHARAQ - high resolution Shimoura et al.

Rare RI Ring – mass　　 Ozawa et al.

SCRIT - e-RI collision Wakasugi, Suda et al.

SLOWRI- slow beams Wada et al.

Phase-II construction 2007-2012To maximize the potentials of intense RI beams available at RIBF

RI Spin Lab. at RIPS –pol. RI beam Ueno et al.

http://rarfaxp.riken.go.jp/RIBF-TAC05/

in 2008

SHARAQ Spectrometer Sakai et al 2009-External investment by CNS, Univ. of TokyoHigh resolution spectrometer for fast RI beams

p/p ~ 15,000, <1mrad, B=6.8Tm Dispersion matching technique

RI beam as new probe to control q, S, TMissing mass spectroscopy with standard kinematicsSpin-isospin response probed by fast RI beams : transparent at 300A MeV Double charge exchange : double GTR, IVSMR Multi-neutron system, etc.

SAMURAI Spectrometer Kobayashi et al 2011-

versatile spectrometer with a large superconducting magnet a large acceptance exclusive measurements neutron measurements 80cm gap, BL~ 7Tm, Bmax=3T PID limited to A~100

Invariant/missing mass spectroscopy giant resonances single particle states via (p,2p) etc EOS in asymmetric nuclear matter : SAMURAI-TPC Particle correlations in a few-body system 3NF Coulomb breakup for radiative capture c.s. (p,), (n,)

new facility present facility

RIPS

GARIS

SLOWRI

CRIB

Big-RIPS

SRC

IRC

AVF RILAC

RI beam energy available in RIKEN

E/A [MeV]

100

10

1

Fermi energy

Coulomb barrier

SHE physics, chemistry

spin-isospin response

trap

(operated by CNS)

Phase-II programs (installations 2007-2012) [2]Unique facilitiesSLOWRI Wada et al. production of high-purity and slow RI beam with an rf-ion guide system Table-top experiments: Mass spectroscopy (10-5) via MR-TOF system co-linear laser spectroscopy, trap...Rare RI ring Ozawa et al. isochronous storage ring designed for c.w. beams precise mass measurement (10-6) via individual injection/extraction by trigger kickers particle by particle at <1Hz pid at injection/extraction Shell evolution and pairing correlationSCRIT Wakasugi et al. Self-confining Radioactive Ion Target system realized in an electron-ring for e-RI collisions Charge form factor measurement L>1026 /cm2/s for 132Sn for 1 week ->105 pps injection

Feasibility check at KSR, Kyoto-Univ.

RIs trapped by the electron beam

Scattered electron

SCRIT

ebeam

rf-ion guide

isochronous ring

H.Sakurai

[MeV]

[MeV]

ZZ

N

NBased on Audi et al., NPA 729(2003)337

n = S2n(N,Z)-S2n(N+2,Z)

p = S2p(N,Z)-S2p(N,Z+2)

“Shell gap” obtained from mass information

Wakasugi et al., PRL 100, 164801(2008)

Luminosity achieved at KSR, Kyoto Univ. L=2.4x1025 cm-2s-1 7x106 trapped ions during 85ms at 80mA current

SCRIT project in RIKEN L > 1027 cm-2s-1 80mA(KSR) -> 300mA (new ring)

SCRIT Wakasugi et al. Self-confining Radioactive Ion Target system realized in an electron-ring for e-RI scattering

Charge form factor measurement L>1026 /cm2/s for 1 week ->105 pps injection

Feasibility check at KSR, Kyoto-Univ.

RIs trapped by the electron beam

Scattered electron

SCRIT

ebeam

r-process path and RIBF

r-pr

oces

s ab

unan

ce

Mass number

observed valuesw/o shell quenchingw/ shell quenching

beta-decayreaction processes (n,) , (,l), etc

Astrophysics Nuclear Physics RIBFReaction-Q value mass mass measurement RI-RingMean free time T 1/2 -spectroscopy BigRIPS/ZDReaction chain Pn -spectroscopy BigRIPS/ZDCross sections Resonances reaction-studies ZD/SAMURAI

GT, GDR, etcTermination Fissility -spectroscopy BigRIPS/ZD

reaction-studies SAMURAI... ...

Nuclear Reaction Data produced at RIBF

Direct reactions Elastic (p,p), ...　 Inelastic (p,p’), (, ’)... Coulomb Excitation Coulomb Dissociation Quasi-elastic (p,2p), (p,pn) Transfer (d,p), (d,n), ... Charge exchange (p,n), (n,p), ... Double charge exchange

3-N forces d+p elastic pionic atom (d, 3He)

Heavy ion induced reactions Total interaction c.s. One-, two-nucleon knock-out reaction Fragmentation reaction Fission reaction Fusion reaction Central collisions .....

Indirect for (p,), (n, ), ...

resonant states, indirect for (p,), (n, ),...

neutrino-induced reactions, B(GT)

EOS, E0, E1, E2 ...

EOS

EOS

EOS

termination of r-process, EOS

Related to nuclear astrophysics

RIBF ： the world-largest in-flight facility　　　　 Phase-I for RIB production has been completed.　　　 Phase-II installations are to be constructed/funded.　　　　 Bunch of data will be produced for coming years.

Relationship between nuclear physics and astrophysics　　　　 Properties of r-process nuclei　　　　　 nucleo-synthesis　　　　 EOS in asymmetric nuclear matter　　　　　 SN explosion 、 outer-crust of neutron stars, gravitational wave

　　　　 Exchange of needs and seeds, ideas　　　　　 OMEG 、 Nuclear reaction data center in Hokkaido Univ.　　　　　 JFNA

Initiation and leadership for nuclear astrophysics??

RIPSGARIS

~100 MeV/nucleon

CRIB (CNS) BigRIPS/ZeroDegree

~5 MeV/nucleon

350-400 MeV/nucleon

Old facility

New facility 350 MeV/nucleon up to U

1st beam in 2006

Phase–I 2007-Accelerators + BigRIPS/ZeroDegree

Phase-IIFurther construction forexperimental instrumentations2007~2012 (plan)

RIBF Facility Layout

Reactions for in-beam spectroscopy with fast RI beam

RI beam energy [A MeV]

Coulomb barrier

Fermi energy30

5

Fusion

Deep inelastic

250

Intermediate energy Coulomb excitation 2+, B(E2), 1-, B(E1),...Proton inelastic scattering 2+,

2, 3-, 3...

Projectile fragmentation 2+, 4+, 6+, 8+, 10+...Quasi-elastic (Knock-out reaction) (p,2p) ….....

RI beam at RIBF

deceleration of RI beamw/ materials

Transfer reaction (, t)

Transfer reaction (d, p) type coincidencelifetime measurement...

Phase-I layout

Experimental set-ups

ZDS: Zero-Degree forward Spectrometer

-spectroscopy

in-beam gamma spectroscopymissing mass spectroscopy

total reaction cross sections

(d,3He) Pol.d+p

ZeroDegree Spectrometer

Budget Status and Construction PlanApproved in FY08 Operation for 5months Facility Construction SHARAQ (high resolution) BT line (2M$ for FY08) SAMURAI (large-acceptance) magnets, detectors(15M$ for FY08-11)

Requested for FY09 Operation budget More than 6 months Construction budget for SCRIT (e-RI) and a new injector

FY10 and later Other facilities : RI-ring, SLOWRI

SHARAQ

SAMURAIZeroDegree

SLOWRI

SCRIT

RI-ring

Management/Operation Status at the New Facility

Efforts to provide stable and intense beams at the new facility R&D for charge-stripper 28GHz ECRIS development completed in next March 48Ca commissioning up to IRC : 200pnA max.

Half a Year Delay of MT schedule due to a problem of carry-over oil in the refrigerators of the SRC and BigRIPS cryogenic system. MT will start in this Oct. & Nov.: ZeroDegree commissioning etc.

PAC Three PAC meetings since 2007 Feb. Next PAC will be in 20-21st Nov. this year

Establishment of International Collaboration Framework China, France (LIA), Germany (EMMI), USA(JUSTIPEN) In near future, Canada (TRIUMF), USA (JUSEIPEN)

JNAC: Japan Nutrition Analysis Center Japan National Aerobatic Club Jesus Name Apostolic Church Java Network Application Controller Joint Needs Assessment Committee Jamshedpur Notified Area Committee Japan-North American Commission on Cooperative Mission

K980-MeV Intermediate stage Ring Cyclotron (IRC)

World’s First and StrongestK2600MeVSuperconducting Ring Cyclotron

World’s Largest Acceptance9 TmSuperconducting RI beam Separator

400 MeV/u Light-ion beam345 MeV/u Uranium beam

SRC

BigRIPS

~250-300 MeV/nucleon RIB