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Feb. 2003

50 分 => Talk なら 35 枚だが、 lecture だと少なめ？. Feb. 2003. Nuclear-structure studies with fast exotic beams. Tohru Motobayashi (RIKEN). Ring Cyclotron (1987) + RIPS (~1990) - RIKEN fast exotic beam or RI beam by projectile fragmentation v/c ~ 0.3 (40-90 MeV/nucleon)

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Feb. 2003

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  1. 50 分 => Talk なら 35 枚だが、lecture だと少なめ？ Feb. 2003 CNS Summer School

  2. Nuclear-structure studies with fast exotic beams Tohru Motobayashi (RIKEN) Ring Cyclotron (1987) + RIPS (~1990) - RIKEN fast exotic beam or RI beam by projectile fragmentation v/c ~ 0.3 (40-90 MeV/nucleon) c.f. RIBF => 200-300 MeV/nucleon, wide range of nucl. “In-beam”g- and particle spectroscopy => nuclear structure of unstable nuclei magicity loss in n-rich nuclei with N=8, 20 => reactions involved in (explosive) nuclear burning solar neutrino production, novae burning CNS Summer School

  3. RIKEN Accelerator Research Facility and RI Beam Factory Project 135 MeV/nucleon for light nuclei 0 350 MeV/nucleon up to U 1 2 1st beam in 2006 under consideration CNS Summer School

  4. Coulomb excitation of N = 20 nuclei Disappearance of the sd-pf shell gap for 32Mg and 30Ne MSU RIKEN CNS Summer School

  5. 1+ (M1) Solar neutrino production Coulomb dissociation of 8B RIKEN-2 (98) RIKEN-I (94) C.D.: insensitive to M1 resonance CNS Summer School

  6. How can we study nuclear structures with fast Radio-isotope (RI) beams ? 1) Direct reactions for nuclear-structure studies 2) RI beams of fragmentation scheme 3) Inverse kinematics 4) Two methods of spectroscopy Doppler-shifted g-rays Particle decays from unbound states 5) Some examples CNS Summer School

  7. direct reaction => nuclear structure information E PID q bam = probe target = object examples: (p,p’), (d,p), … reaction channel: PID of ejectile excited level: E (q) cross section => deformation single particle strength angular distribution => angular momentum direct (first-order) mechanism CNS Summer School

  8. 58Ni(d,p)59Ni E =15 MeV (1962) 4 distance along the focal plane (momentum) 2 3 l- dependence of angular distribution 1 0 CNS Summer School

  9. projectile fragmentation projectile ~ 0 v~ vbeam target by Ong Hooi Jin wide range of (unstable) nuclei regardless of chemical properties E > 50 MeV/nucleon CNS Summer School

  10. inverse kinematics / methods of spectroscopy RI (beam) + target (probe) -----> projectile-like products g decays (bound) particle decays (unbound) ------> target-like products recoil particles target-g reaction-channel ID: PID of the projectile-like product state ID: g ray (Doppler-shifted) invariant mass reaction: inelastic (Couex, C.D., (p,p’) … cex, fratmentation, knockout transfer CNS Summer School

  11. Advantage / disadvantage of fast RI beams poor (intensity) 0.1 - 105 pps dirty (emittance) 2cm f, 1~2 deg. Spread high energy efficient setups good reactions (large s) g-ray measurement invariant mass thick targets forward focusing CNS Summer School

  12. Detector arrays CNS Summer School

  13. 300 pps CNS Summer School

  14. Coulomb excitation of N = 20 nuclei Disappearance of the sd-pf shell gap for 32Mg and 30Ne MSU RIKEN CNS Summer School

  15. Locations of 2+ / 4+ states of n-rich around N=20 - “Island of inversion” - 34Mg (Z=12, N=22) Fragmentation of 36Si (2x104 cps) 30Ne (Z=10, N=20) proton inelastic 30Ne (0.2 cps) 2+ 2+ 4+ Yoneda et al., Phys. Lett. B566 (2003)84 Yanagisawa et al., Phys. Lett. B566 (2003)84 CNS Summer School

  16. 34Si + 2H -> 34Si + g + X (2x104 cps) (Z=14, N=20) g-g coincidence counts 34Si Gate: 2+ - 0+ : newly assigned CNS Summer School Iwasa et al., Phys. Rev. C67 (2003) 064315

  17. 8B Coulomb dissociation 50 - 90 MeV/nucleon DALI (208Pb) DALI HODO CNS Summer School

  18. Coulomb dissociation 7 B e Virtual photons p c.f. Nakamura halo nuclei 8 B = Coulomb excitation to unbound states c.f. Mueller, Mueller, … spectroscopy 2 0 8 P b 8B+208Pb -> 7Be+p+208Pb (C.D.) virtual photon theory or DWBA 8B(g,p)7Be (abs.) detailed balance 7Be(p,g)8B (capt.) large s thick target (intermediate energy) experiments with R.I. beams CNS Summer School

  19. Large yield detailed balance virtual photon number (intermediate energy) thick target charged particle detection indirect i.e.nucl. force / higher order / E2 100 ~ 1000 100 ~ 1000 but CNS Summer School

  20. kinematics Erel <= pp, p7Be, qp-Be DErel : Independent of DEin p+X, T0=100 AMeV, Erel=1 MeV, Dq=0.5 deg.Dv=1% DErel=200 keV CNS Summer School

  21. 1+ (M1) Solar neutrino production Coulomb dissociation of 8B RIKEN-2 (98) RIKEN-I (94) C.D.: insensitive to M1 resonance CNS Summer School

  22. spectroscopy with fast exotic beams RI (beam) + target (probe) - inverse kinematics -----> projectile-like products g decays (bound) particle decays (unbound) ------> target-like products recoil particles target-g reaction-channel ID: PID of the projectile-like product good state ID: g ray (Doppler-correction) invariant mass reaction w. large s: inelastic (Couex, C.D., (p,p’) … cex, fratmentation, knockout transfer forward focusing,thick target, efficient detectors => CNS Summer School

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