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H. Sakurai

Challenges for the r-process and EOS. H. Sakurai. RIKEN Nishina Center for Accelerator-Based Science. Congratulations! Establishment of Japan Forum of Nuclear Astrophysics (JFNA) 1 st Workshop organized by JFNA. RIKEN RI Beam Factory (RIBF). Experiment facility. To be funded In phase II.

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H. Sakurai

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  1. Challenges for the r-process and EOS H. Sakurai RIKEN Nishina Center for Accelerator-Based Science

  2. Congratulations! Establishment of Japan Forum of Nuclear Astrophysics (JFNA) 1st Workshop organized by JFNA

  3. RIKEN RI Beam Factory (RIBF) Experiment facility To be funded In phase II Old facility Accelerator RIPS SHE (eg. Z=113) GARIS 60~100 MeV/nucleon ~5 MeV/nucleon RILAC SCRIT AVF ZeroDegree SAMURAI fRC RRC SLOWRI SRC IRC RI-ring SHARAQ BigRIPS CRIB (CNS) 350-400 MeV/nucleon New facility • Intense (80 kW max.) H.I. beams (up to U) of 345AMeV at SRC • Fast RI beams by projectile fragmentation and U-fission at BigRIPS • Operation since 2007

  4. Progress of Research Opportunities with RI Beams Construction of a dedicated facility for RI beam production via the projectile fragmentation 1990- 0th-generation at LBL 1st-generation at LISE-GANIL

  5. Challenges in Methodology with fast RI beams at RIPS ~40-70 A MeV and A < 60 transmission method for nuclear radii information energy-dependence of total reaction cross sections, e.g. 11Be in-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,g)8B missing mass spectroscopy Spectroscopy on the heaviest hydrogen 7H polarized rare-isotope beams for electro-magnetic moments Anomaly of quadrupole moments in the B isotopes via beta-NMR techniques

  6. New frameworks for the new region of nuclear chart Nuclear Structure: Shell evolution Nuclear Matter: New forms Neutron-rich Nuclei Stable Nuclei neutron-skin nuclei ? ? ? neutron-halo nuclei N=16 N=6 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)

  7. Challenge for r-process path and explosion in supernovae 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 nuclei Mass, life-time, decay mode Mass number 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 1987A 5

  8. Challenge to investigate EOS of neutron matter from nuclei to neutron stars B. A. Brown, PRL85 (2000) 5296 3NF T=3/2 channels? density dependence? Normal density Elastic d+p for T=1/2 Nuclear structure in very neutron-rich nuclei for T=3/2? Heavy-ion Collisions to achieve r~2-3r0 ? E/A [MeV] 3P2 correlation pairing gap? Density depencence? r (fm-3) 1S correlation BCS-BEC crossover in dilute system (r ~ 0.1r0) ? ???? Role of di-neutron in skin? : collectivity, transfer reactions

  9. RI beam production via in-flight method RI production RI beam separator （to collect and separate RI with analyzing magnets） target Heavy ion accelerator （to make reactions Be, C, etc） （to accelerate nuclei） Advantage of fission via U beam RI beam Fission reaction via 238U beam Yield rate of 78Ni via fission is about 1､000 times higher than via fragmentation. Probability N=50 10,000:1 Fragmentation reaction via 86Kr beam 78Ni Proton number

  10. Super-conducting Ring Cyclotron（SRC） Cyclotron accelerator 　　－＞beam intensity is very high Acceleration of U up to 70% of speed of light 　　－＞thick target can be used －＞world-highest intensity for RI beam Total weight 8300 ton Highest bending power （8Tm) Maximum magnetic field 3.8 T SRC Dec. 2005

  11. RIBFAcceleration performance Performance of RIKEN Accelerator Complex AVF AVF+RRC+SRC for m/q=2 inc. pol. d With fRC (SRC) 350 MeV/u U88++ (8Tm) I = 1 pA (goal) SRC With fRC (IRC) IRC

  12. RI beam separatorBigRIPS Large acceptance for fission fragment 50% superconducting quadrupole magnets High transmission for RI beams Tandem-type separator with two stages SRC BigRIPS RI beam Nov. 2006 completed Second stage NC dipole mag. Beam from SRC SC quadrupole mag. First stage Production target 8

  13. New isotopes of 125, 126Pd T. Onishi et al, JPSJ 77 (08)083201. Bρ: 7.438 Tm, ΔP/P=2% Isomer 96Rb 238U + Be(7mm) at 345 MeV/u 2007 MAY-JUNE Total dose: 3.6×1012

  14. Identification of new isotopes 125,126Pd T. Onishi et al, JPSJ 77 (08)083201. 126 (3counts) A/Q resolution(r.m.s): 0.041% at Z=46 Br resolution (r.m.s): 0.02% Cf. 124Pd 19 counts, 125Pd(cand.) 1count at GSI, 1997 PLB 415, 111 (97); total dose ~1x1012

  15. Great expansion of nuclear world by RIBFIntensity > 1 particle/day(EPAX@GSI) Exploration of the Limit of Existence New Element 278113 04 July 23 18:55 57 fb protons In-flight U fission & P.F. Projectile Fragmentation 78Ni ~0.1 particles/sec. (2007) by 10pnA 350 MeV/u U-beam 10 particles/sec. (goal) by 1pmA neutrons

  16. BigRIPS /ZeroDegree Exploration into “Isospin Frontier” toward the drip-lines Reaction study fit for high energy domain 200-300A MeV 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 PID section RIB production

  17. 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 regions Specific programs with deuteron beams BigRIPSin-flight production of fast rare-isotope beams Ground state properties and low lying excited states via decay spectroscopy / transmission method: particle stability, T1/2, Qb, sR, 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 beams Collectivity 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

  18. Flag ship regions at neutron-rich side 238U beam New isotopes between Z=20 to 60 Maaaany new ones !! R-process path T1/2 at A>80 New 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 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

  19. Half-lives of nuclei beyond 78Ni at RIBF Magicity at Z=28 and N=50 ? more accurate measurement for 78Ni at RIBF P.T.H, PRL 94, 112501(2005) 78Ni ~10 particles/week at MSU 78Ni ~20 particles/day at RIBF at present Z=28 N=50 79Ni at RIBF 77Co at RIBF

  20. Large Room for B(E2) B(E2)-1 [1/W.u] 82 100Sn double magicity? 208Pb 126 48Ni double magicity? deformation region? proton number 50 132Sn N=82 magicity? 82 28 78Ni double magicity? 50 20 N=34 new magicity? N=28 magicity? 2001 20 neutron number

  21. 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

  22. Others needed additionally Position sensitive detectors for low-E neutrons for (p,n) Faster Beam-line detectors for more intense RIB Thinner Beam-line detectors for heavy RIB Better resolution detectors for E of RIB Faster DAQ Second Level Trigger Multi-Trigger Control System 3H target for (t,p) ? neutron target for (n,gamma) ?

  23. Phase-II construction 2007-2012 To maximize the potentials of intense RI beams available at RIBF http://rarfaxp.riken.go.jp/RIBF-TAC05/ SCRIT - e-RI collision Wakasugi, Suda et al. SAMURAI - large acceptance Kobayashi et al. in 2011 Rare RI Ring – mass Ozawa et al. SHARAQ - high resolution Shimoura et al. SLOWRI- slow beams Wada et al. in 2008 RI Spin Lab. at RIPS –pol. RI beam Ueno et al.

  24. SHARAQ Spectrometer Sakai et al 2009- External investment by CNS, Univ. of Tokyo High resolution spectrometer for fast RI beams p/Dp ~ 15,000, Dq<1mrad, Br=6.8Tm Dispersion matching technique RI beam as new probe to control Dq, DS, DT Missing mass spectroscopy with standard kinematics Spin-isospin response probed by fast RI beams : transparent at 300A MeV Double charge exchange : double GTR, IVSMR Multi-neutron system, etc.

  25. SAMURAI SpectrometerKobayashi 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,g), (n,g)

  26. RI beam energy available in RIKEN E/A [MeV] new facility present facility SRC spin-isospin response Big-RIPS 100 IRC RIPS Fermi energy 10 AVF Coulomb barrier RILAC CRIB GARIS 1 SHE physics, chemistry (operated by CNS) SLOWRI trap

  27. Phase-II programs (installations 2007-2012) [2] Unique facilities SLOWRI 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 correlation SCRIT 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. rf-ion guide isochronous ring Scattered electron SCRIT ebeam RIs trapped by the electron beam

  28. “Shell gap” obtained from mass information Dn = S2n(N,Z)-S2n(N+2,Z) [MeV] Z N Dp = S2p(N,Z)-S2p(N,Z+2) [MeV] Z N H.Sakurai Based on Audi et al., NPA 729(2003)337

  29. Scattered electron SCRIT ebeam RIs trapped by the electron beam 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. 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)

  30. r-process path and RIBF r-process abunance observed values w/o shell quenching w/ shell quenching beta-decay reaction processes (n,g) , (n,l), etc Mass number AstrophysicsNuclear PhysicsRIBF Reaction-Q value mass mass measurement RI-Ring Mean free time T 1/2b-spectroscopy BigRIPS/ZD Reaction chain Pn b-spectroscopy BigRIPS/ZD Cross sections Resonances reaction-studies ZD/SAMURAI GT, GDR, etc Termination Fissility b-spectroscopy BigRIPS/ZD reaction-studies SAMURAI ... ...

  31. Nuclear Reaction Data produced at RIBF Related to nuclear astrophysics Direct reactions Elastic (p,p), ... Inelastic (p,p’), (a, a’)... 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 ..... EOS, E0, E1, E2 ... Indirect for (p,g), (n, g), ... resonant states, indirect for (p,g), (n, g),... neutrino-induced reactions, B(GT) EOS EOS termination of r-process, EOS EOS

  32. 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??

  33. RIBF Facility Layout Old facility Phase-II Further construction for experimental instrumentations 2007~2012 (plan) RIPS GARIS ~100 MeV/nucleon ~5 MeV/nucleon BigRIPS/ZeroDegree CRIB (CNS) 350-400 MeV/nucleon New facility Phase–I 2007- Accelerators + BigRIPS/ZeroDegree 350 MeV/nucleon up to U 1st beam in 2006

  34. Reactions for in-beam g spectroscopy with fast RI beam RI beam energy [A MeV] Intermediate energy Coulomb excitation 2+, B(E2), 1-, B(E1),... Proton inelastic scattering 2+, bM2, 3-, bM3... Projectile fragmentation 2+, 4+, 6+, 8+, 10+... Quasi-elastic (Knock-out reaction) (p,2p) … ..... 250 RI beam at RIBF deceleration of RI beam w/ materials Transfer reaction (a, t) 30 Fermi energy g-g coincidence lifetime measurement ... Transfer reaction (d, p) type Deep inelastic Fusion 5 Coulomb barrier

  35. in-beam gamma spectroscopy missing mass spectroscopy Phase-I layout b-spectroscopy total reaction cross sections (d,3He) Pol.d+p ZeroDegree Spectrometer Experimental set-ups ZDS: Zero-Degree forward Spectrometer

  36. Budget Status and Construction Plan Approved 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 SCRIT ZeroDegree SAMURAI SLOWRI RI-ring SHARAQ

  37. 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)

  38. 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

  39. World’s First and Strongest K2600MeV Superconducting Ring Cyclotron SRC 400 MeV/u Light-ion beam 345 MeV/u Uranium beam BigRIPS World’s Largest Acceptance 9 Tm Superconducting RI beam Separator ~250-300 MeV/nucleon RIB K980-MeV Intermediate stage Ring Cyclotron (IRC)

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