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Recent activities with slow and stopped RI at Tohoku-Cyclotron

International Workshop on Physics of Nuclei at Extremes, Jan. 2010, TokyoTech. Recent activities with slow and stopped RI at Tohoku-Cyclotron. Introduction of CYRIC Production of medium- heavy neutron-rich nuclei RF Ion-guide ISOL Recent results half life of 103m Tc and 105m Ru

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Recent activities with slow and stopped RI at Tohoku-Cyclotron

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  1. International Workshop on Physics of Nuclei at Extremes, Jan. 2010, TokyoTech Recent activities with slow andstopped RI at Tohoku-Cyclotron • Introduction of CYRIC • Production of medium- heavy neutron-rich nuclei • RF Ion-guide ISOL • Recent results • half life of 103mTc and 105mRu • g-factor of 109mRh and 132mI 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 Physics of Nuclei at Extremes, TokyoTech

  2. Cyclotron facility A A AVF Cyclotron (K=110 MeV) B HM12 Cyclotron (production of positron emitters for PET) 1 RI production 3 High-intensity fast neutron (Ep = 20-80 MeV、E = 1 MeV 、106n/cm2sA) 4 Large acceptance g-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 10 1 B 9 2 RF ion-guide isotope separator on-line (RFIGISOL) 8 6 2 6 Surface ionization ion source for electron EDM measurement 4 3 7 5 Cyclotron and Radioisotope Center (CYRIC), Tohoku University Slow RIB facility Physics of Nuclei at Extremes, TokyoTech

  3. 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 High-melting point ↓ hardly produced by ISOLDE type ISOL ↓ Development of RFIGISOL (BigRIPS, FRS) Purpose and background 132Sn Z=50 (Sn) Stable Z=28 (Ni) N=50 N=82 100Zn Physics of Nuclei at Extremes, TokyoTech RI をプローブとした物性研究へ展開

  4. 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 238U etc. ⇒ Middle-heavy neutron-rich nuclei Comparison of RI Production methods RFIGISOL⇒High-melting-point and short-life RI Physics of Nuclei at Extremes, TokyoTech

  5. =Ion + RF field + 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? Fission products ISOL RFIGISOL Recoil with several MeV Ionizer DC field Gas stream U target U target f 200 mm Recoil, ~MeV Exit hole f 1 mm Proton Proton 3-kPa He ~3000K 300 mm Physics of Nuclei at Extremes, TokyoTech

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

  7. Typical parameters of RFIGISOL Stop and thermalization: He gas(3 kPa), ~104 cm3 Target: natural Uranium (Effective thickness: 190 mg/cm2) Guide: DC field (~5 V/cm) Giude: RF field (~3 MHz, ~50 Vpp) Acceleration: DC 30 kV m Mass spectrometer Proton beam (50 MeV, 1 mA) Extraction: Gas jet +DC field (~1 kV) CYRIC 2nd target room Physics of Nuclei at Extremes, TokyoTech

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

  9. Primary beam: Proton, 50 MeV, 1 μA Yield at beam-line end, after passing mass spectrometer Yields with RFIGISOL Bold: 2009 Normal: 2007 Stable line 132Te~1000 0.1 111Tc ~1100 111Ru ~7100? 114Pd ~9000 [particles/sec] Obtained Yields 1 mb 112Rh ~4000 112Ru ~400 109Tc ~1300 109Ru ~1300 Fission production cross section 10 mb 107Tc ~2400 107Ru ~4600 100Nb ~1300 100Zr ~1300 100Y ~400 105Tc ~2400 ∝Expected Yields 91Rb ~400 132Sn 80As ~200 80Ge ~200 125Pd (BigRIPS) Recent experiments 100Zr T1/2: 103mTc, 105mRu 119Cd ~800 119Ag ~400 78Ni g-factor: 109mRh, 132mI Physics of Nuclei at Extremes, TokyoTech

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

  11. Setup of life-time measurement 2. Transfer： ~5 s • Detectors for life-time measurement • good time resolution • Planar Ge: ~1 ns • BaF2: ~0.01 ns • System: 5 ns • good energy resolution • 10-ns isomers→Measurable • Beam monitor (co-axial Ge) 1. Implantation: ~1τ 3. Measurement: ~1τ Physics of Nuclei at Extremes, TokyoTech

  12. Recent experiments (1) Life of Isomer 105Ru 103Tc 1ch = 0.25 nsec [K. Shimada, H. Ouchi, Tohoku Univ.] [Y. Miyashita, Tohoku Univ. / RIKEN] (5/2-,3/2-) 3/2+,5/2+ (5/2)+ Preliminary results • 163.74 keV : 55 ns → ~18 ns • 246.26 keV : ~15 ns Preliminary result • 83.38 keV : ~40 ns Physics of Nuclei at Extremes, TokyoTech

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

  14. Time differential Perturbed Angular Correlation methods (TDPAC) Bext g1=0 °, g2 intensity distribution det. 3 180° det. 1 0° det. 2 90° Physics of Nuclei at Extremes, TokyoTech

  15. (2) g-factor in 109mRh (Ex=225.98 keV, T1/2=1.66 ms) + 0.17 - 0.03 g = 0.78 [mN] [Y. Miyashita, Tohoku univ. / RIKEN] On-line TDPAC method (Time differential perturbed angular correlation) TDPAC spectrum B = 0.34 T Detection system Tape transport system BaF2 detectors Ge detectors Magnet (0.34 T) Tape Physics of Nuclei at Extremes, TokyoTech

  16. Magnetic moments magnetic moment or - 0.02 - 0.03 - 0.03 - 0.05 109Rh 225 keV state simple single-particle + excited-core coupling a proton core: excited 2+ or 4+ in 108Ru 1g9/2, 1g7/2, 2d5/2, 2d3/2, 3s1/2 m of single-particle ground state Physics of Nuclei at Extremes, TokyoTech

  17. Magnetic moment in 132mI Tanigaki, PRC80(2009)034304 PAC spectrum in the Ni foil ( Bhf = +26.5 ±0.5 T ) BaF2 detectors×3 m = +(2.06 ± 0.18)mN Physics of Nuclei at Extremes, TokyoTech

  18. Comparison of a simple jj-coupling model of odd-odd nucleus odd-odd nucleus is described based on a jj-coupling model m(mN) Ref. Experiment +2.06 ± 0.18 This work +2.22 ± 0.30 Singh et al. by TIPAC Calculation (pg7/2)(nd3/2)−1 +2.40 (pd5/2)(nd3/2)−1 +2.83 Values for empirical g factors (pg7/2) +2.80 Av. 131,133I (pd5/2) +2.81 Av. 129,131I (nd3/2)−1 +0.75 Av. 131Te, 133Xe ←proton-odd ←neutron-odd 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： 105mRu，103mTc • Planar Ge-BaF2 system • g-factor and μ： 109mRh，132mI • TDPAC • Next plan: g-factor of 105mRu Physics of Nuclei at Extremes, TokyoTech

  20. Thank you for your attention Physics of Nuclei at Extremes, TokyoTech

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