1 / 22

Spin- isospin studies with the SHARAQ Spectrometer

Aizu2010 Nov 10 - 13, 2010. Spin- isospin studies with the SHARAQ Spectrometer. Tomohiro Uesaka & Y. Sasamoto , K. Miki, S. Noji University of Tokyo for the SHARAQ collaboration. RI beam factory @ RIKEN. Superconducting Ring Cyclotron (SRC). Isotope separator BigRIPS. SHARAQ.

gur
Download Presentation

Spin- isospin studies with the SHARAQ Spectrometer

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Aizu2010 Nov 10-13, 2010 Spin-isospin studies with the SHARAQ Spectrometer Tomohiro Uesaka & Y. Sasamoto, K. Miki, S. Noji University of Tokyo for the SHARAQ collaboration

  2. RI beam factory @ RIKEN Superconducting Ring Cyclotron (SRC) Isotope separator BigRIPS SHARAQ

  3. What is SHARAQ? SHARAQ is a HIGH-RESOLUTION magnetic spectrometer constructed at RIBF by University of Tokyo - RIKEN collaboration.

  4. Design Specifications of SHARAQ T.U. et al., NIMB B 266 (2008) 4218. Maximum rigidity 6.8 Tm Momentum resolution dp/p = 1/14700 Angular resolution ~ 1 mrad Momentum acceptance ± 1% Angular acceptance ~ 5 msr SDQ QQDQD D1 Q3 D2 "GANIL-made" CRDC

  5. Nuclear Spin-Isospin Responses For more than 70 years, we have dedicated our efforts to study of nuclear spin-isospin responses. → knowledge of fundamental properties of finite nuclei and infinite nuclear matter in-medium interaction correlation in nuclei → essential inputs to astrophysics nucleo-synthesis, neutron star physics . . . neutrino physics weak response of nuclei

  6. Isovector monopole resonances Isovector monopole resonances higher tone of GT & IAS DT=1 DL=0 DS= 0, 1 2hw excitations Experimental data are scarce. no good (efficient) probes to probe IV(S)MR so far

  7. RI beams induced charge exchange reactions Spectroscopy with RI-beam induced reactions Traditional example:(t,3He) experiments POTENTIAL of (new) RI beam induced reactions New SELECTIVITIES (DT, DS, DL, Dp) missing in stable-beam induced reactions ex. the (10C,10B*(IAS)) reaction to probe isovector non-spin-flip (DT=1, DS=0) excitations. → search for Isovector Monopole Resonances Access to kinematical region which are inaccessible by stable beams. large Q-value in RI beam induced charge exchange reaction(exothermic) →RECOILLESS excitation of HIGH-Exstates Isovector Spin Monopole Resonance via the (12N,12C) reaction Double Gamow-Teller Resonance via the (10C,10Be)reactions Tetra-neutron state via the 4He(8He,8Be[=2a]) reaction

  8. First series of experiments with SHARAQ Studies of IV(S)MR, taking advantages of RI beam induced charge exchange reactions (RICE) • 90Zr, 208Pb(t,3He) at 300 MeV/u (Miki et al.) search for b+ type isovector spin monopole resonances • 7Li, 90Zr (10C,10Bg) at 200 MeV/u (Sasamoto et al.) search for b+ type isovectornon-spin monopole resonances • 90Zr(12N,12C) at 200 MeV/u (Noji et al.) establish exothermic charge exchange reaction to probe b- type isovector spin monopole resonances

  9. 90Zr, 208Pb(t,3He) at 300 MeV/u (Miki et al.)

  10. Experimental conditions Beam Primary : 4He 320MeV/u 300pnA Secondary : triton 300MeV/u 1x107pps Purity > 99% Obtained spectra 208Pb(t ,3He) 208Tl 90Zr (t ,3He) 90Y Resolution(FWHM) DE～2.5MeV - energy spread of 2nd beam – 1.9MeV - energy loss in target – 1.4MeV Dq～0.5deg - angular spread of 2nd beam – 7mrad - multiple scattering in target – 6mrad 0 < Ex < 70 MeV 0 < q < 3 deg @

  11. 208Pb(t,3He)208Tl @ 300MeV/u • Stat. accuracy (0deg) ~ 2% for 1msr ・1MeV –bin • Bumps at 4MeV, 15MeV -- peak around the forward angle DL=0 ?

  12. IVSMR(b +) for 208Pb Miki et al. • IVSMR(DL=0)  Forward-peak • Comparison between0.0-0.5 deg .vs. 0.5-1.0 deg spectra

  13. IVSMR(b +) for 208Pb Miki et al. • IVSMR(DL=0)  Forward-peak • Comparison between0.0-0.5 deg .vs. 0.5-1.0 deg spectra • Significant DL=0 component around 12MeV First observation of b+-type IVSMR

  14. IVSMR(b +) for 208Pb Miki et al. • IVSMR(DL=0)  Forward-peak • Comparison between0.0-0.5 deg .vs. 0.5-1.0 deg spectra • Significant DL=0 component around 12MeV • Theoretical predictions :TDA(SGII), TDA(SIII)Hamamoto, Sagawa : Phys.Rev.C 62 (2000) 024319 Very Preliminary First observation of b+-type IVSMR IVSMR TDA(SIII)reproduces the data well.

  15. IVSMR(b +) for 90Zr Miki et al. • IVSMR(DL=0)  Forward-peak • Comparison between0.0-0.5 deg .vs. 0.5-1.0 deg spectra • Significant DL=0 component around 20MeV • Theoretical predictions :TDA(SGII), TDA(SIII)Hamamoto, Sagawa : Phys.Rev.C 62 (2000) 024319 Very Preliminary IVSMR SDR Detailed analyses to deduce absolute value of the transition strength are in progress

  16. 90Zr(12N,12C) at 200 MeV/u (Noji et al.)

  17. b- type IVSMR (12N,12C) reaction at 200－300 MeV: BEST probe to b- type IVSMR Selective excitation of st mode 12N(1+) →12C (0+) Surface sensitivity (HI reaction) Exothermic reaction good momentum matching 90Zr(12C, 12N) data were taken Analysis to subtract BG is now being done.

  18. 7Li, 90Zr (10C,10Bg) at 200 MeV/u (Sasamoto et al.)

  19. (10C,10Bg) Reaction • Use super-allowed Fermi transition (in projectile) to probe isovector non-spinflip mode in target nuclei DT=1, DS=0 NO stable beam induced reaction with the selectivity • 1022 keV g-ray is a signature of the non-spinflip transition

  20. 7Li(10C,10Bg) : proof of the principle Sasamoto et al. 1022 keVg-ray

  21. Search for IV-nonspin-MR in 90Zr Sasamoto et al.

  22. Summary • RI beam induced charge exchange (RICE) reactions can be tools toprobe hardly studied states such as IV(S)MR double GT states. . . • In the first series of SHARAQ experiments, IV(S)MR are studied by taking advantage of RICE 90Zr, 208Pb(t,3He) at 300 MeV/u (Miki et al.) 7Li, 90Zr (10C,10Bg) at 200 MeV/u (Sasamoto et al.) 90Zr(12N,12C) at 200 MeV/u (Noji et al.)

More Related