1. Overview of RIBF
H. Sakurai
RIKEN Nishina Center

2. 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
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

3. 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
~ MeV/nucleon RIB
K980-MeV
Intermediate stage Ring Cyclotron (IRC)

4. 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

5. 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

6. 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

7. 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

8. 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

9. Identification of new isotopes 125,126Pd
T. Onishi et al, JPSJ 77 (08)
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

10. Programs at BigRIPS/ZeroDegree in 2007-2008
May A MeV 238U beam　0.02 pnA (max)
Two new isotopes, 125,126Pd (Z=46), Onishi et al. JPSJ 77 (08)
Nov. 2008　345A MeV 238U beam 0.4 pnA(max)
45 new isotopes in Mn to Ba, JPSJ 79 (10)
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

11. Press-Conference on June 8th, 2010
IOP physicsworld.com
“Radioisotopes galore at RIKEN”

12. 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

13. 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, (2009)
New states in 31,32,33Na
PRC 81, R (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, (2009)
Total interaction
cross sections
for the neutron-rich
Ne isotopes
19C
20C
22C
31Ne
Takechi, Otsubo et al.,
Niigata 2010 symposium

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

15. 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

16. The First Decay Spectroscopy at RIBF
U beam to access A~110 region
Intensity 0.8 pnA max.
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)

17. 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

18. 209Bi + 70Zn → 278113 + n CN CN a a 1st chain a a a a s = 23+30-15 fb
MeV
TOF ns
30.33 mm
MeV
TOF ns
30.08 mm
209Bi + 70Zn → n
278113 CN
278113 CN
K. Morita et al., 73   (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 :55 (JST)
274111
274111 a a
11.15 MeV
(PSD+SSD)
9.260 ms
30.40 mm
=11.31 MeV
(PSD+SSD)
34.3 ms
29.61 mm
270Mt
270Mt a a
10.03 MeV
(PSD+SSD)
7.163 ms
29.79 mm
2.32 MeV (escape)
1.63 s
29.45 mm
266Bh
266Bh
s = 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 :18 (JST)
262Db
262Db
MeV(PSD)
40.9 s
30.25 mm
MeV(PSD)
0.787 s
30.47 mm
s.f.
s.f. 18
K. Morita et al., JPSJ 76, (2007) 18

19. 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-

20. 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 !!