h. sakurai riken nishina center for accelerator-based science challenges for the r-process and eos
TRANSCRIPT
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