1. - 1 - T.Roger – 13-10-08 - ENST Workshop Saclay - Probing 11 Li halo-neutrons correlations via (p,t) reaction with the active target MAYA T. ROGER (GANIL)

2. - 2 - T.Roger – 13-10-08 - ENST Workshop Saclay - (1) I. Tanihata et. al. (Phys. Rev. Lett. 55, 2676 (1985)) (2) I. Tanihata et. al. (Phys. Lett. B 287, 307 (1992)) (3) I.J. Thompson et. al. (Phys. Rev. C 49, 1904 (1994)) (4) H. Simon et. al. (Phys. Rev. Lett. 83, 496 (1999)) (5) T. Nakamura et. al. (Phys. Rev. Lett. 96, 252502 (2006)) (6) H. Esbensen et. Al. (Nucl. Phys. A542, 310 (1992)) (7) R. Sanchez et. al. (Phys. Rev. Lett. 96, 033002 (2006)) (8) I. Tanihata (Private Communication) Matter radius measurement of 11 Li (1)  1st observation of halo phenomenon Momentum distribution of core-neutrons (2,3,4)  Momentum correlations  Role of s & p-wave mixing Coulomb disociation of 11 Li (5,6)  3 body model w.f. with 2n correlations Charge & matter radii measurements (7,8)  Angular correlations of the neutrons State of the art of 11 Li (non exhaustive!)

3. - 3 - T.Roger – 13-10-08 - ENST Workshop Saclay -  Probing halo structure via transfer reaction  1 nucleon transfer : probes spectroscopy  2 nucleons transfer : probes strength of correlation  extraction of angular distributions + DWBA analysis = informations on the structure of the halo  Study of the 2-neutron transfer reaction on a proton target Method Experiment E1055 (2-neutron transfer)

4. - 4 - T.Roger – 13-10-08 - ENST Workshop Saclay - TISOL source + ISAC II accelerator  up to 5kHz of 11 Li @ 5A MeV  Low energy + Low beam intensity  Use of Active Target! Experimental system

5. - 5 - T.Roger – 13-10-08 - ENST Workshop Saclay - Experimental system

6. - 6 - T.Roger – 13-10-08 - ENST Workshop Saclay - The active target MAYA C.E. Demonchy et al. (Nucl. Instrum. Methods A 573, 145 (2007))

7. - 7 - T.Roger – 13-10-08 - ENST Workshop Saclay - Tracking techinque Reaction plane : e - drift time resolutionobservable 2mmRange 1°  angle 0.5° - 2°2D angle 2D angles : Centroïds Tracking using PADS and Wires

8. - 8 - T.Roger – 13-10-08 - ENST Workshop Saclay - Results of the algorithm Y MAYA (mm) 0 80 160 Depth (mm) 90180 11 Li

9. - 9 - T.Roger – 13-10-08 - ENST Workshop Saclay -  CM = 145° E 9Li = 19.1 MeV E t = 36.3 MeV t = 1.5keV/mm p dt étage « ΔE » : Si (700µm) + étage « E » : CsI (3cm)  Selection of the ions : ΔE - E  2 solid identification stages + 1 gazeous stage  large dynamic for the selection Selection of particles  CM = 35° E 9Li = 53.9 MeV E t = 1.4 MeV R t = 50mm 11 Li 9 Li étage « ΔE » : gaz (5cm) + étage « E » : Si (700µm)  At least 1 identified particle from 20° CM to 160°CM  11 Li mass : S 2n = 386 (20) keV

10. - 10 - T.Roger – 13-10-08 - ENST Workshop Saclay - 2-neutron transfer : results Angular distributions for transitions to 9 Li (GS) & 9 Li* (2.69 MeV) p( 11 Li, 9 Li)t @ 3A MeV (I.Tanihata)p( 11 Li, 9 Li)t @ 4.3A MeV (T.Roger)

11. - 11 - T.Roger – 13-10-08 - ENST Workshop Saclay - I.J. Thompson et al. (Phys. Rev. C 49, 1904 (1994)) Calculations including simultaneous and sequential transfers for ≠ 11 Li models with various s² % 11 Li: s 2 & p 2 10 Li 9 Li (G.S.) s sequentials simultaneous p 51543.640.33P3 64313.39-0.32P2 9433.05-0.33P0 (%)‏ (fm)‏(MeV)‏ (p 1/2 ) 2 wt(s 1/2 ) 2 wtR m rmsE 11 G.S. CRC Calculations (I.J. Thompson)

12. - 12 - T.Roger – 13-10-08 - ENST Workshop Saclay - Simultaneous Transfers Use 3-body wave functions and The relative neutron-neutron states must be equal One Direct Step Need p+ 11 Li and t+ 9 Li Optical Potentials Becchetti & Greenlees global optical potential Sequential Transfers Use 2-body wave functions &, and & Should have complete sets of d* and 10 Li* wfs: d bound state only 10 Li* s-wave and p-wave only Two successive steps Need d+ 10 Li Optical Potential Daehnick et al global optical potential CRC Calculations (I.J. Thompson)

13. - 13 - T.Roger – 13-10-08 - ENST Workshop Saclay - Magnitude varies shows s 2 strengths in the 11 Li w.f. Shapes vary Shows interference between s- and p- wave parts of 10 Li. Note: this interference will diminish if a complete set of 10 Li states included at same energies. (May reappear when energies in 10 Li* included properly) Simultaneous 2n-transferSequential 2n-transfer CRC Calculations (I.J. Thompson)

14. - 14 - T.Roger – 13-10-08 - ENST Workshop Saclay - Results I. Tanihata et al. (Phys. Rev. Lett. 100, 192502 (2008)) 3A MeV 4.3A MeV  P2 and P3 ~ reproduce the amplitudes ... but minimum missed by ~20°  Not easy to come to a conclusion yet!!

15. - 15 - T.Roger – 13-10-08 - ENST Workshop Saclay - Perspectives  Use a more realistic optical potential :  Try to reproduce elastic scattering data  More realistic calculations i.e. include coupling to 1n transfer channel ( like 1 H( 8 He, 6 He)t : N.Keeley et al. (Phys. Lett. B 646, 222 (2007)) ) CH89 potential :  W S > 0 !!  large radius JLM potential  3 parameters (normalisation V, W & data)  Re-Normalisation of data necessary!!!

16. - 16 - T.Roger – 13-10-08 - ENST Workshop Saclay - Perspectives  Do the experiment at higher energy (get rid of compound nucleus effects)  20A MeV 11 Li beam possible at RCNP (Osaka) ? No compound nucleus effect for (p,t) … but strong resonance populated by (p,p)!! (  IAS of 12 Li(G.S.)!!)

17. - 17 - T.Roger – 13-10-08 - ENST Workshop Saclay - Perspectives  Study the transition to 9 Li (2.69) more into details  Excited core configuration for 11 Li (G.S.)???  To be continued...

18. - 18 - T.Roger – 13-10-08 - ENST Workshop Saclay - MAYA@TRIUMF Collaborators H. Savajols, T. Roger, M. Caamaño, W. Mittig +, and P. Roussel-Chomaz GANIL, Bd Henri Becquerel, BP 55027, 14076 Caen Cedex 05, France I. Tanihata*, M. Alcorta**, D. Bandyopadhyay, R. Bieri, L. Buchmann, B. Davids, N. Galinski, D. Howell, W. Mills, R. Openshaw, E. Padilla-Rodal, G. Ruprecht, G. Sheffer, A. C. Shotter, M. Subramanian, M. Trinczek, and P. Walden TRIUMF, 4004 Wesbrook Mall, Vancouver, BC, V6T 2A3, Canada R. Kanungo and A. Gallant Saint Mary’s University, 923 Robie St., Halifax, Nova Scotia B3H 3C3, Canada M. Notani and G. Savard ANL, 9700 S. Cass Ave., Argonne, IL 60439, USA I. J. Thompson LLNL, L-414, P.O. Box 808, Livermore CA 94551, USA * RCNP Osaka University ** Institute de Estructura de la Materia, Madrid + NSCL MSU ++ MAYA’s Technical Staff as : J.F. Libin, P. Gangnant, C. Spitaels, L. Olivier & G. Lebertre