Overview of RIBF H. Sakurai RIKEN Nishina Center

RIKEN RI Beam Factory (RIBF) Experiment facility To be funded In phase II Old facility Accelerator SHE (eg. Z=113) RIPS GARIS SCRIT 60~100 MeV/nucleon ~5 MeV/nucleon RILAC AVF ZeroDegree SAMURAI fRC RRC SRC SLOWRI IRC RI-ring CRIB (CNS) SHARAQ (CNS) BigRIPS <10 MeV/nucleon 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

SRC 400 MeV/u Light-ion beam 345 MeV/u Uranium beam BigRIPS 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)

Exploration of the Limit of Existence stable nuclei ~300 nuclei unstable nuclei observed so far ~2700 nuclei drip-lines (limit of existence)（theoretical predictions) ~6000 nuclei magic numbers New Element 278113 04 July 23 18:55 57 fb 4000 species to be produced (1000 more new isotopes) protons neutrons Projectile Fragmentation 78Ni ~0.1 particles/sec. (2007) by 10pnA 350 MeV/u U-beam In-flight U fission & P.F. 10 particles/sec. (goal) by 1pmA 4 4

Liberation from Stable Region Shell Evolution : magicity loss and new magicity Spherical Deformed Shape ? Shell gap？ Single particle level？ Cluster formation? Role of 3NF ? Magicity loss ？ 　　50、82、126、184 E(2+) Dynamics of new “material” : Neutron-skin（halo） Density distribution Quantum-objects having two surfaces Skin thickness？Density distribution？ Role of skin in reactions？ Pairing in skin？ di-neutrons? Exotic modes of skin？ neutron skin Neutron+ proton 陽子・中性子 一様物質 proton- neutron matter r neutrons RIBF provides data for nuclei far from the stability line Challenges in establishing new frame work of nuclear physics

Challenge for r-process path and explosion in supernovae Synthesis up to U （r-process） 　　unknown neutron-rich nuclei 　 theoretical predictions only 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 crust of neutron star Equation-of-State in asymmetric matter Higher density: 3NF (T=3/2)? Dilute matter : BEC, cluster-formation? 1987A

Experimental Devices available at the new facility in 2009 SHARAQ(2009~) High resolution spectrometer BigRIPS (2007~) 2nd 1st production target BigDpol(2009~) ZeroDegree (2008~) For polarized deuteron only SRC

Delivery of tagged RI-beam Based on two-stage separator scheme T. Kubo et al. Cocktail beam A, Z, Q mixed Tagged beam Dispersive focus To RI-beam delivery line & experimental set-ups TOF& E Bmeasurement Identify RI-beam species Z, A/Q by measuring E, B, TOF in an event-by-event mode using beam-line detectors on the 2nd stage. Aim at tagging rate up to 1 x 106 pps. Standard New Scheme Br-TOF-dE-E Br-TOF-dE Z, A, Q Z, A/Q

Identification of new isotopes 125,126Pd T. Onishi et al, JPSJ 77 (08)083201. 125 (22counts) 126 (3counts) A/Q resolution(r.m.s): 0.041% at Z=46 Br resolution (r.m.s): 0.02% DT resolution (r.m.s.): 40 psec Total dose 3.6x1012 for 25 hrs I ~0.01 pnA on average Cf. 124Pd 19 counts, 125Pd(cand.) 1count at GSI, 1997 PLB 415, 111 (97); total dose ~1x1012

Programs at BigRIPS/ZeroDegree in 2007-2008 May 2007 345A MeV 238U beam　0.02 pnA (max) Two new isotopes, 125,126Pd (Z=46), Onishi et al. JPSJ 77 (08) 083201 Nov. 2008　345A MeV 238U beam 0.4 pnA(max) 45 new isotopes in Mn to Ba, JPSJ 79 (10) 073201 Proton number Z N=82 N=50 Dec. 2008　345A MeV 48Ca beam Day-One Experiments for Island-of-Inversion 48Ca beam 170pnA(max) 　　　　 31Ne 10 /sec/100pnA, 32Ne 5 /sec/100pnA N=20 Neutron number N

Press-Conference on June 8th, 2010 IOP physicsworld.com “Radioisotopes galore at RIKEN” http://physicsworld.com/cws/article/news/42915

Setup of Day-One Experiments at BigRIPS/ZDS In-beam gamma spectroscopy Coulomb breakup BigRIPS+ZDS DALI-II NaI-based gamma Detectors target target total interaction cross sections at BigRIPS 2nd-stage ZeroDegree Spectrometer Experimental set-ups

DayOne Experiments in Dec., 2008 -The first data in the “island-of-inversion” - Coordinated by Aoi Spectroscopy of 32Ne and the “island-of-inversion” N=20 345A MeV 48Ca beam 170pnA(max) E(2+) = 722 keV Island-of-inversion Doornenbal, Scheit et al. PRL 103, 032501 (2009) New states in 31,32,33Na PRC 81, 041305R (2010) 28-32Ne 31Ne 10 pps/100pnA 32Ne 5 pps/100pnA N=16 A new candidate of halo nuclei 31Ne via Coulomb breakup Nakamura et al., PRL 103, 262501(2009) Total interaction cross sections for the neutron-rich Ne isotopes 19C 20C 22C 31Ne Takechi, Otsubo et al., Niigata 2010 symposium

Next Generation Gamma-Detector System SHOGUN Scintilator based High resOlution Gamma-ray spectrometer for Unstable Nuclei H. Scheit et al. simulation by Doornenbal

Low-lying Excited States in 24O via (p,p’) - The First Missing Mass Spectroscopy at RIBF - Spokespersons : Valerie Lapoux and Hideaki Otsu May, 2010 The state-of-art detector MUST2 from France coupled with BigRIPS/ZDS setup Characteristics of the N=16 new magic number ? … in O isotopes Structure of a drip-line nucleus, possible neutron-skin or halo MUST2 MUST2 GOAL EXCITATION ENERGY SPECTRUM FOR 24O  24O(p,p’)24O* shielding Target Holder 24O E(2+)  Sn = 3.7 MeV + states above S2n = 6.35 MeV ? PPAC TOOLS beam Particle spectroscopy of UNBOUND states SET- UP RIBF beam (unique intensities) + high-performance telescope array +large-acceptance spectrometer Kinematics, (p,p’) reactions Beam time

The First Decay Spectroscopy at RIBF U beam to access A~110 region Intensity 0.8 pnA max. 0.1-0.2 pnA on average Sumikama, Nishimura, et al. Half life measurements for r-process nuclei Nishimura et al., PRL in press Beta-gamma spectroscopy Sumikama et al., in preparation Delayed gamma spectroscopy for isomers H.Watanabe et al., PLB in press for 109Nb STOP Detector ( Decay experiment ) Clovers (RIKEN) LaBr3 (Milano) 9 layers of DSSD (RIKEN, TUS)

to deliver more intense beam and more opportunities for SHE New Injector RILAC2 to deliver more intense beam and more opportunities for SHE To deliver more intense Xe/U for the new facility Commissioning in Dec.2010 fRC BigRIPS (RIBF) New Injector RILAC2+ 28GHz SC-ECRIS AVF RILAC GARIS (SHE) RRC 300 days per year for SHE!! IRC SRC 17

209Bi + 70Zn → 278113 + n CN CN a a 1st chain a a a a s = 23+30-15 fb 36.75 MeV TOF 44.61 ns 30.33 mm 36.47 MeV TOF 45.69 ns 30.08 mm 209Bi + 70Zn → 278113 + n 278113 CN 278113 CN K. Morita et al., 73 2593-2596 (2004) a a 1st chain 11.68 MeV (PSD) 344　μs 30.49 mm 11.52 MeV (PSD) 4.93　ms 30.16 mm 23-July-2004 18:55 (JST) 274111 274111 a a 11.15 MeV 6.149+5.003 (PSD+SSD) 9.260 ms 30.40 mm 0.88+10.43=11.31 MeV (PSD+SSD) 34.3 ms 29.61 mm 270Mt 270Mt a a 10.03 MeV 1.136+8.894(PSD+SSD) 7.163 ms 29.79 mm 2.32 MeV (escape) 1.63 s 29.45 mm 266Bh 266Bh s = 23+30-15 fb a a 2nd chain 9.08 MeV (PSD) 2.469 s 30.91 mm 9.77 MeV (PSD) 1.31 s 29.65 mm 2-April-2005 2:18 (JST) 262Db 262Db 204.05 MeV(PSD) 40.9 s 30.25 mm 192.32 MeV(PSD) 0.787 s 30.47 mm s.f. s.f. 18 K. Morita et al., JPSJ 76, 045001 (2007) 18

New Devices of RIBF Suda Yoneda To maximize the potentials of intense RI beams available at RIBF for several 100 – 1000 species Rare RI ring ZeroDegree Ozawa mass half-life excited states deformation charge radii matter radii charge distribution matter distribution EM moments single particle states astrophysical reactions giant resonances exotic modes HI collisions (EOS) mass 2013- to be funded 2008- SLOWRI IRC-to-RIPS BT 2012- gas-catcher multi-use 2012- Wada Ueno to be funded to be funded SAMURAI SCRIT Suda Yoneda SHARAQ spectrometer U Tokyo 2009- 2012- 2010-

Summary BigRIPS: 45 new isotopes in 4days achieved with a U beam ZDS : New results for island-of-inversion region via in-beam gamma, transmission method, Coulomb dis. decay spectroscopy at A~110 missing mass spectroscopy with MUST2 for O-24 two step alignments with RIB BigDpol: pol-d+p elastic scattering for 3NF (p2p) for light and neutron-rich nuclei at a small spectrometer SAMURAI: is under construction, starting in 2012 SCRIT: will start to have e-RI scattering SHE: new linac RILAC2 will give more opportunities since 2011 Other devices (SLOWRI, Rare RI-ring…) are to be funded Many opportunities for international collaborations !!