26th Jan. 2010Physics of Nuclei at Extremes, TokyoTech1 Recent activities with slow and stopped RI at Tohoku-Cyclotron Cyclotron and Radioisotope Center (CYRIC), Tohoku Univ.: K. Shimada, S. Hoshino, S. Izumi, H. Ouchi, A. Sasaki, T. Wakui, T. Shinozuka, RIKEN: Y. Miyashita KUR: M. Tanigaki JAEA: M. Asai, N. Sato International Workshop on Physics of Nuclei at Extremes, Jan. 2010, TokyoTech 1. Introduction of CYRIC 2. Production of medium- heavy neutron-rich nuclei 1. RF Ion-guide ISOL 3. Recent results 1. half life of 103m Tc and 105m Ru 2. g-factor of 109m Rh and 132m I

26th Jan Physics of Nuclei at Extremes, TokyoTech 2 A B A AVF Cyclotron (K=110 MeV) B HM12 Cyclotron (production of positron emitters for PET) 1 RI production 3 High-intensity fast neutron ( Ep = MeV 、  E = 1 MeV 、 10 6 n/cm 2  s  A) 4 Large acceptance  -ray detector array (Hyperball2) (6 Clover type ＋ 14 Single type) 5 Heavy-ion irradiation (in air) 7 Material irradiation 8 High-resolution beam line and large scattering chamber 9 Charged particle radiation therapy 10 Beam swinger and Large solid angle neutron detection system Slow RIB facility 2 RF ion-guide isotope separator on-line (RFIGISOL) 6 Surface ionization ion source for electron EDM measurement Cyclotron and Radioisotope Center (CYRIC), Tohoku University Cyclotron facility

26th Jan Physics of Nuclei at Extremes, TokyoTech 3 Purpose and background Nuclear structure of the medium-heavy neutron-rich nuclei Life times and B(E2) of isomers Nuclear moments  Independent of nuclear structure model  Single-particle energies and configurations of wave function Known magnetic moments N=50N=82 Z=50 Z=28 Stable (Sn) (Ni) High-melting point ↓ hardly produced by ISOLDE type ISOL ↓ Development of RFIGISOL (BigRIPS, FRS) 100 Zn 132 Sn RI をプローブとした物性研究へ展開

26th Jan Physics of Nuclei at Extremes, TokyoTech 4 Comparison of RI Production methods Projectile-fragment separators In-flight A primary beam > A 2ndary beam ISOL ( ⊃ RFIGISOL) A primary beam <<A 2ndary beam <A target Target fragmentation  Fission of 238 U etc. ⇒ Middle-heavy neutron-rich nuclei RFIGISOL ⇒ High-melting-point and short-life RI

26th Jan Physics of Nuclei at Extremes, TokyoTech 5 Correction of fission products with gas Stop, thermalization and ionization ISOL: Thermal diffusion and surface ionization RFIGISOL: Large He gas volume and avoidance of neutralization  Independent of chemical properties  Highest ionization energy of He How are the fission products collected to the nozzle? 300 mm  200 mm Exit hole  1 mm U target Fission products 3-kPa He Gas stream DC field RF field RFIGISOL ISOL ~3000K U target Proton Recoil with several MeV Recoil, ~MeV =Ion + + Ionizer

26th Jan Physics of Nuclei at Extremes, TokyoTech 6 Φ220 mm exit hole 1.2 mm  Base film: 50-μm-thick kapton Electrodes: 360 rings at 0.6-mm intervals E DC E RF Track of ions RF electrodes (RF carpet) y x Trapping potential (for ion in resonance)  x y RF phase originally developed by M. Wada, RIKEN

26th Jan Physics of Nuclei at Extremes, TokyoTech 7 Typical parameters of RFIGISOL Target: natural Uranium (Effective thickness: 190 mg/cm2) Stop and thermalization: He gas (3 kPa), ~10 4 cm 3 Guide: DC field (~5 V/cm) Giude: RF field (~3 MHz, ~50 V pp ) Extraction: Gas jet +DC field (~1 kV) Mass spectrometer Proton beam (50 MeV, 1  A) Acceleration: DC 30 kV CYRIC 2nd target room m

26th Jan Physics of Nuclei at Extremes, TokyoTech 8 Photo ～ RFIGISOL chamber proton Acceleration: DC 30 kV U target He gas: 3 kPa DC field: 5 V/cm RF field: 3 MHz,50 V pp Mass spectrometer

26th Jan Physics of Nuclei at Extremes, TokyoTech Rh ~ Ru ~ Nb ~ Zr ~ Y ~ Rb ~ As ~ Ge ~ Cd ~ Ag ~ Ni Fission production cross section Yields with RFIGISOL Primary beam: Proton, 50 MeV, 1 μA Yield at beam-line end, after passing mass spectrometer Stable line 107 Tc ~ Ru ~4600 [particles/sec] 109 Tc ~ Ru ~ Tc ~ Ru ~7100? 114 Pd ~9000 Bold: 2009 Normal: Tc ~ Zr 132 Sn 10 mb 1 mb Pd (BigRIPS) Obtained Yields ∝ Expected Yields 132 Te ~1000 Recent experiments T 1/2 : 103m Tc, 105m Ru g-factor: 109m Rh, 132m I

26th Jan Physics of Nuclei at Extremes, TokyoTech 10 Recent experiments (1) Life-time measurement

26th Jan Physics of Nuclei at Extremes, TokyoTech 11 Setup of life-time measurement Beam monitor (co-axial Ge) 1. Implantation: ~1τ 2. Transfer ： ~5 s 3. Measurement: ~1τ Detectors for life-time measurement good time resolution  Planar Ge: ~1 ns  BaF 2 : ~0.01 ns  System: 5 ns good energy resolution 10-ns isomers → Measurable

26th Jan Physics of Nuclei at Extremes, TokyoTech 12 Preliminary results – keV : 55 ns → ~18 ns – keV : ~15 ns 1ch = 0.25 nsec 105 Ru 103 Tc [Y. Miyashita, Tohoku Univ. / RIKEN] [K. Shimada, H. Ouchi, Tohoku Univ.] Preliminary result – keV : ~40 ns Recent experiments (1) Life of Isomer (5/2-,3/2-) 3/2+,5/2+ (5/2)+

26th Jan Physics of Nuclei at Extremes, TokyoTech 13 Recent experiments (2) g-factor measurement

26th Jan Physics of Nuclei at Extremes, TokyoTech 14 Time differential Perturbed Angular Correlation methods (TDPAC) det. 1 0° det. 2 90° det °    °   intensity distribution B ext

26th Jan Physics of Nuclei at Extremes, TokyoTech 15 Ge detectors Magnet (0.34 T) [Y. Miyashita, Tohoku univ. / RIKEN] On-line TDPAC method (Time differential perturbed angular correlation) Tape transport system Detection system g = [N][N] BaF 2 detectors Tape TDPAC spectrum B = 0.34 T (2) g-factor in 109m Rh (Ex= keV, T1/2=1.66 ms)

26th Jan Physics of Nuclei at Extremes, TokyoTech 16 I  =3/2 + I  =5/2 + I  =3/2 + I  =5/2 + (2 + ) ⊗ (g 9/2 ) 93Nb (3)4.8049(2) (4 + ) ⊗ (g 9/2 ) 93Nb (1)2.8773(1) (2 + ) ⊗ (g 7/2 ) 123Sb (2)1.8672(2) (4 + ) ⊗ (g 7/2 ) 123Sb (1) (2) (2 + ) ⊗ (d 5/2 ) 141Pr (3)3.1587(2) (4 + ) ⊗ (d 5/2 ) 141Pr (3) (4) (2 + ) ⊗ (d 3/2 ) 169Tm 0.871(2)0.586(2) (4 + ) ⊗ (d 3/2 ) 169Tm 3.294(19)2.317(5) (2 + ) ⊗ (s 1/2 ) 193Ir (1)0.5389(2) (4 + ) ⊗ (s 1/2 )1 93Ir (10)1.5719(3) I  =3/2 + I  =5/ or magnetic moment 109 Rh 225 keV state simple single-particle + excited-core coupling a proton core: excited 2 + or 4 + in 108 Ru 1g 9/2, 1g 7/2, 2d 5/2, 2d 3/2, 3s 1/2  of single-particle ground state Magnetic moments

26th Jan Physics of Nuclei at Extremes, TokyoTech 17 ( B hf = ±0.5 T ) PAC spectrum in the Ni foil Magnetic moment in 132m I  = +(2.06 ± 0.18)  N BaF 2 detectors×3 Tanigaki, PRC80(2009)034304

26th Jan Physics of Nuclei at Extremes, TokyoTech 18 Comparison of a simple jj-coupling model of odd-odd nucleus  (  N ) Ref. Experiment ± 0.18 This work ± 0.30 Singh et al. by TIPAC Calculation (  g 7/2 )( d 3/2 ) − (  d 5/2 )( d 3/2 ) − Values for empirical g factors (  g 7/2 ) Av. 131, 133 I (  d 5/2 ) Av. 129, 131 I ( d 3/2 ) − Av. 131 Te, 133 Xe ←proton-odd ←neutron-odd odd-odd nucleus is described based on a jj-coupling model

26th Jan Physics of Nuclei at Extremes, TokyoTech 19 Summary CYRIC facility 2 cyclotrons and 10 beam lines Production of RI beam using RFIGISOL RFIGISOL ISOL specified for high-melting-point and short-life nuclei Large He gas buffer and RF carpet Recent results life-time ： 105m Ru ， 103m Tc  Planar Ge-BaF2 system g-factor and μ ： 109m Rh ， 132m I  TDPAC Next plan: g-factor of 105m Ru

26th Jan Physics of Nuclei at Extremes, TokyoTech 20 Thank you for your attention