1. V. Lapoux DAPNIA/SPhN EURISOL 16-20 Jan. 06 Physics & Instrumentation Trento, 16-20 January 2006 Drip-lines : limit of nuclear binding, large isospin Exploration : new structures EXOTIC NUCLEI Tests : nuclear modelling & interactions V NN (T z ) Probe the structure & spectroscopy at large isospin  Measure unbound states Tools & detection devices  n,  p Extension of the systematics of neutron excitation along isotopic chains Unbound states in dripline nuclei

2. V. Lapoux DAPNIA/SPhN EURISOL 16-20 Jan. 06 Nuclear structure towards the drip-lines : phenomena to explore & to understand Neutron skins halo,clusters Change in shell structure New magic numbers Local properties (N,Z) 4 He 6 He halo 8 He 4 He Neutron skin Evolution of structure at large isospin ? 2006 : what is known ? 2016 : area to explore ?

3. V. Lapoux DAPNIA/SPhN EURISOL 16-20 Jan. 06 Search for low-lying resonances and study of neutron excitations MUST : Y.Blumenfeld et al., NIM A421, 421 (‘99) CATS : S. Ottini et al., NIM A431, 476 (‘99). beam MUST (8 in a wall) + CATS (p,p’) probe Particle spectroscopy A Z (p,p’) p’ AZAZ A Z*  A-1 Z +n … p Beam profile : CATS 1 & 2 Detection of the light charged recoil particle in a dedicated array  the strip-wall device MUST bound excited states close to thr : E. Khan et al., 20 O(p,p’) PLB 490 (‘00) 45 C. Jouanne, V. L., et al., 10,11 C(p,p’) PRC 72, 014308 (’05) Modification of the usual shell structure new magic numbers Neutron- rich 20,22 O

4. V. Lapoux DAPNIA/SPhN EURISOL 16-20 Jan. 06 Prototype of (p,p’) & direct reactions at low energy : 8 He(p,p’) SPIRAL beam MUST+CATS structure of 8 He :  + 4n? 0+0+ 2+2+ S n =2.5 S 4n =3.1 S 2n = 2.1 8 He 3.6MeV ? >>> Specific tools direct reactions in inverse kinematics and missing mass method Unbound excited states, low-lying resonances of weakly-bound nuclei : A.Lagoyannis et al., 6 He(p,p’) @ Ganil, PLB 518, 27 (‘01). 6 He : 2n-halo 8 He : neutron-skin Resonances of 7,8 He Exotic structures

5. V. Lapoux DAPNIA/SPhN EURISOL 16-20 Jan. 06 8 He 8 He excitation energy spectrum 7 He 1n transfer : 8 He(p,d) 7 He g.s 0 + 2+2+ 6 He 2n Transfer 8 He(p,t) 6 He 8 He +p @ 15.6 MeV/n F. Skaza, PhD thesis SPhN Unbound states studies : what we have learnt from SPIRAL beam E405S experiment, MUST collab. * Large (p,d), (p,t) cross sections DWBA not valid GENERAL framework : Coupled Reactions calc. needed, PLB619, 82 (‘05) Structure of the 8 He nucleus via direct reactions on proton target 2+ 3.62 ± 0.14 MeV Γ = 0.3 ± 0.2 MeV ? 5.4 ± 0.5 MeV Γ = 0.3 ± 0.5 MeV

6. V. Lapoux DAPNIA/SPhN EURISOL 16-20 Jan. 06 Nuclear landscape towards the drip-lines 2 468101214 N 16 2 4 6 He 6 Z 8 4 He borromean He C N O H n pp dt 8 He 11 Li F 31 Li Be 14 Be B 12 19 22 23 242006 Which drip-line nuclei have their identity card complete ? Masses, size, densities, neutron excitation, low-lying spectroscopy, Shell structure ? 6 He Drip-line : 8 He neutron-skin

7. V. Lapoux DAPNIA/SPhN EURISOL 16-20 Jan. 06 Nuclear landscape towards the drip-lines 16 182022242628 N 30 18 Z 4 He2006 10 12 14 16 8 Low-lying resonances ? Neutron skin ? Density Profiles ? New shell effects ? structure of 24 O ? 24 O 23 N 22 C 31 F 30,31,32 Ne 33 Na 34 Mg 38 Mg Next drip-line nuclei ? 37 Na 363339 Tarasov97 Sakurai97 Notani02, Lukyanov02 43 Si

8. V. Lapoux DAPNIA/SPhN EURISOL 16-20 Jan. 06 neutrons fp sd d 5/2 d 3/2 s 1/2 stability f 7/2 p 3/2 sd-fp 20 N = 16 Z=14 30 Si N = 20 8 N = 8 p 3/2 p 1/2 s 1/2 Shell effects far away from stability with new generations of RIB s Local properties (Z,N) N=34,40,70 instead of N=50,82 ?  EURISOL systematics of neutron excitations vs N Search for new magic numbers neutrons fp sd d 5/2 d 3/2 s 1/2 drip-line N = 16, Z=8, 24 O f 7/2 p 3/2 sd-fp N = 14 22 O N = 16 N = 8 16 N=16  Learnt from 1 st generation of RIBs (1h11/2 - ) 12 82 (f7/2)

9. V. Lapoux DAPNIA/SPhN EURISOL 16-20 Jan. 06 82 50 50 ? 28 40 110 Zr 132-140... Sn 78 Ni 20 20 8 2 2 8 82 70 28 neutron drip-line known up to Z=8 ( 24 O )… doubly magic stable nuclei doubly magic unstable nuclei ? drip-lines & properties in the vicinity of new doubly magic nuclei ? Explorations of nuclear landscape using SPIRAL2, GSI, EURISOL beams Explorations of nuclear landscape using SPIRAL2, GSI, EURISOL beams FAIR

10. V. Lapoux DAPNIA/SPhN EURISOL 16-20 Jan. 06 Z N 2016 : 2016 : 10 years of exploitation of SPIRAL2 Regions of the chart of nuclei accessible with SPIRAL2 beams Primary beams:  deuterons  heavy ions

11. V. Lapoux DAPNIA/SPhN EURISOL 16-20 Jan. 06 Z N EURISOL the 10 9 /s beams of EURISOL are the 10 4 /s of SPIRAL2 and co. If the beams are new ( 36 Ne ? 60-68 Ca ?) or rare at present ( 24 O few/s at GANIL, RIKEN) with EURISOL : counting rates less or around 10 3 -10 5 /s Will all our beams be as intense as we believe ??? 2016 : 2016 : starting EURISOL beams

12. V. Lapoux DAPNIA/SPhN EURISOL 16-20 Jan. 06 Alpha-clusters states Skin and halos Soft collective modes Evolution of neutron excitation Mn vs N along isotopic chains Exotic shapes and resonances One-particle state Spectroscopic factors Beams Variety A,Z Limit of nuclear binding, I  2009+2016+ Z N Going closer to driplines with higher intensities : opened physics fields Which beams ? We want to gain in exoticity Complete the (p,p’) chains O ( 24 O), Ne + Mg, Si, S, Ar +spectroscopy of neutron-rich around N=28, N=40 (new), N=50, N=70 (new) Examples : 38 Ne (if not unbound), 60-70 Ca, 104 Se (Z=34, N=70) Far..far away

13. V. Lapoux DAPNIA/SPhN EURISOL 16-20 Jan. 06 0+0+ 2+2+ S 2n =7.91 S n = 4.95 96 Kr 6? MeV ? Calc : M.V. Stoitsov, et al., Phys. Rev. C68, 054312 (‘03) Data AME2003 0+0+ 4+4+ S 2n =8.5 S n = 5.2 94 Kr ? 0.67 MeV 1.52 2+2+ Similar trend for all neutron-rich EURISOL beams : few bound states

14. V. Lapoux DAPNIA/SPhN EURISOL 16-20 Jan. 06 100 mm MUST : ~30cm behind ! ~10cm compactness due to ASIC technology allows particle -  coincidences MUST 1  MUST 2:  factor 3 larger active area  factor 6 smaller volume of PA  better time resolution NEW GENERATION of MUST array NIM A421, 421 (‘99) MUST2 developed by:  DAPNIA/SEDI : µ-electronics R&D ASIC  GANIL  IPN Orsay 6x6 cm 2 Si Strips 300  m Si(Li) 3mm CsI 1.5 cm MUST collaboration : CEA-DAPNIA, GANIL, IPN Orsay Si(Li) 4.5 mm CsI 3 cm 4 x 4 segments Si strips 300  m 100 x 100 mm 2 X, Y, T, E 128X 128Y EE MUST22004-6 MUr à STrips 2

15. V. Lapoux DAPNIA/SPhN EURISOL 16-20 Jan. 06 Measure a complete set of direct reactions : investigation of nuclear structure form factors (densities) + Neutron excitations via (p,p ’) spectroscopic factors via (d,p) (p,d) transfers Spin & parity via transfer on polarized targets Probes, reactions and beam energies At which energies do we need to accelerate ? Optimize between : Energies required by physics case & experimental difficulties 1. Access to high energy excited states : higher E inc compared to SPIRAL2 2. energy resolution for excitation energies  lower E inc collaboration MUST2 : DAPNIA, GANIL, IPN-Orsay Assets : Assets : beam tracking + LCP arrays E-TOF,E-DE, ID Experimental method Direct reactions Analysis :Microscopic potentials potentials Coupled channels +CDCC 0+0+ 2+2+ ?

16. V. Lapoux DAPNIA/SPhN EURISOL 16-20 Jan. 06 20 c.m 40 c.m Structure studies from direct reactions with EURISOL beams (100MeV/n) small uncertainty in Theta(LAB)  huge variation in excitation energies

17. V. Lapoux DAPNIA/SPhN EURISOL 16-20 Jan. 06 60 c.m 80 c.m 20 c.m Structure studies from direct reactions with EURISOL beams (25MeV/n)

18. V. Lapoux DAPNIA/SPhN EURISOL 16-20 Jan. 06 particle spectroscopy, requirements * Angular coverage (FWD and BWD)  4  & Granularity ( Dx ~ Dy ~ 1mm ) * Large Dynamics and Particle Id [ p,d,t, 3,4,6,8 He 6 Li Energies up to ~ 300 MeV tot E-De and E-TOF correlations for identification low E threshold needed ~ < 300 KeV to measure small c.m. angles * Kinematics Reconstruction of the Scattering angle for variable (!) beam optical quality angle & impact on target required * Coupling with Gamma-spectroscopy,  Compacity Means …  array of Si strip telescopes  stage-telescopes Si + SiLi +CSI  For each channel,TAC for TOF, DT (part. det) ~ 500 ps to ~ 1ns start : particle in the Si stage stop : time before target : beam detector  2 beam tracking detectors for x,y, T event by event 1mm x-y, 300 ps DT  ~ 0.5deg MUST@ 15 cm Intrinsic DE (Si) ~ 50 keV DE resolution (with thin target ~ 1mg/cm 2 ) ~ 400-700 keV Precision on centroid, bound states ~ 30 keV resonant states ~ 100-200 keV  ASICs Requirements for improved charged particle spectroscopy Charged-Particle spectroscopy Charged-Particle spectroscopy  needed to explore unbound states  (p,p’), (p,d) (p,t) (d,p) Thin light targets p, d  E ~ 400keV to 1 MeV

19. V. Lapoux DAPNIA/SPhN EURISOL 16-20 Jan. 06 Detection for EURISOL experiments 78 Ni +p  p’ + 78 Ni*  p + 76 Ni + 2n p’ + 78 Ni*  p + 74 Ni + 4n Phase space background due to neutrons produced by decaying unbound states 78 Ni +p  d + 77 Ni unbound?  d + 76 Ni + n d + 77 Ni*  d + 74 Ni + 3n 78 Ni +p   t + 76 Ni  t + 76 Ni *  t + 75 Ni* + n  t + 74 Ni + 2n ID, E vs Theta of LCP 78 Ni(p,p’) 78 Ni* 78 Ni(p,t) 76 Ni 78 Ni(p,d) 77 Ni + A Z ID of forward focused heavy fragments : Spectrometer or SiLi, CSI arrays close to targets ? + neutron detection Low S n, S 2n, S 4n,… Check alpha-neutrons correlations :: needs LCP and neutron devices granularity & efficiency

20. V. Lapoux DAPNIA/SPhN EURISOL 16-20 Jan. 06 Improved detection for EURISOL experiments Steps beyond in the detection : - ASIC technology ( Application Specific Integrated Circuit ) (compacity of all devices) - Mixed detection (gamma+ charged particles +… neutrons) : Ex : Ge + Si + scintillator in a crystal-Ge-Si ball array -Higher multiplicities in LCP arrays (3,4,..) challenges in acquisition systems : synchronize separated arrays & triggers needs to reduce dead time + A,Z ID of heavy fragment in a spectrometer or SiLi CsI array + NEUTRON DETECTION Charged-Particle spectroscopy  needed to explore unbound states Thin light targets p, d  E ~ 400keV to 1 MeV  (p,p’), (p,d) (p,t) + Inverse kinematics : good Energy resolution in Eexc requires : beam profile on target  beam tracking detectors + Gamma-ray spectroscopy Gamma-ray spectroscopy  needed to separate close excited states close excited states Thick target  E ~ 20keV (d,p) @ 9 MeV/n 2016 Wishes for Coupled Detection devices

21. V. Lapoux DAPNIA/SPhN EURISOL 16-20 Jan. 06 EURISOL : specific experiments and beams Exotic structure at the neutron drip-line : Ex : 24 O 34-38 Ne Complete the systematic studies of neutron excitation vs N from Z=8 to Z=28 chains  EURISOL Cluster structures : alpha-n correlations & molecular bands Ex : 30 Ne : 5 Alpha + 10 n Probes : (p,p’) + transfer reactions + (p,2p)

22. V. Lapoux DAPNIA/SPhN EURISOL 16-20 Jan. 06 EURISOL : specific experiments and beams Present (1 st generation) intensities : few part/s Needed : (at least) 10 3 -10 5 /s 20-50 MeV/n : enough Looking back in the past ! See multi-nucleon transfer Ex : 9 Be( 13 C, 14 O) 8 He H. Bohlen et al., ZPhysA 330 (’88) 10 Be( 12 C, 14 O) 8 He Th. Stolla et al., ZPhysA 356 (’96) SPIRAL2 production of light exotic nuclei R&D for a 9 Be target allowing 40 kW beam SIMILAR TECHNIQUES FOR EURISOL ?

23. V. Lapoux DAPNIA/SPhN EURISOL 16-20 Jan. 06 conclusions Means BEAMS OF RARE ISOTOPES Today 1/s, EURISOL 10 3 -10 5 /s Means DIRECT PROBES i.E p &d targets, + Polarized p,d DIRECT REACTIONS target: cryogenic D 2 or CD 2 Light charged particle (LCP) detection  -ray detection: future AGATA exotic beam EURISOL EURISOL A Z identification Beam Tracking Devices BTD A+1 Z p E inc ~ 20-50 MeV/n Nearly (~90%) pure beam

24. V. Lapoux DAPNIA/SPhN EURISOL 16-20 Jan. 06 Diffusion (p,p’) en cinématique inverse CATS 2 détection du faisceau (x,y,t) Pre-Amps Si Strip 6x6 cm 2 MUST Si Strips 300  m Si(Li) 3mm CsI 1.5 cm détection d’ions légers x,y,E,t) Z & A ( 1,2,3 H, 3,4 He) gamme étendue E  E+  E+E bas seuil (~ 500 keV) Résolution en position  x,  y ~ 1 mm MUST Y. Blumenfeld et al., NIM A421 (‘99) 471 CATS S. Ottini et al., NIM A431 (‘99) 476

25. V. Lapoux DAPNIA/SPhN EURISOL 16-20 Jan. 06 + Information cruciale apportée par les détecteurs de faisceau 11 C (p,p ’) @ 40,6 MeV/nucléon : l ’effet des CATS sur MUST Analyse : Cédric JOUANNE, Thèse 98-01, CEA-Saclay, DSM/DAPNIA/SPhN C. Jouanne, V. L et al., PRC 72, 014308 (’05) précision centroïde ~ 30keV  E* = 750 keV réactions de référence

26. V. Lapoux DAPNIA/SPhN EURISOL 16-20 Jan. 06 A Z(p,d) A-1 Z Q = S n (A+1,Z)-S n (d) = S n (A+1,Z) - 2.24 MeV Q(p,d)= S n (d)-S n (A,Z) = 2.224 -S n A Z(p,t) A-2 Z Q(p,t)=S 2n (t)-S 2n (A,Z) = 8.482 –S 2n Q 8 He(p,t) = 6.34 Ex : Q 8 He(p,d) = -0.35 0+0+ 2+2+ S n =2.5 S 4n =3.1 S 2n = 2.1 8 He 3.6MeV ? A Z(d,p) A+1 Z Q [ 96 Kr(p,d) ]~ - 2.8MeVQ [ 96 Kr(p,t) ]~ - 0.45 MeV TOOL : TOOL : direct reactions (p,p) (p,d) (p,alpha) & (d,d) (d,p) (d, 3 He) Q 8 He(p,  ) = 3.57MeV Q [ 81 Cu(p,  ) 78 Ni] ~ 7MeV 81 Cu (~ 80-82 Zn) I ~ 10 5 /s Using the A+3 Z+1 nucleus with higher I to produce and excite A Z For beams I spiral2 > ~ 10 4 /s Typical conditions for transfer reactions  ~ 1mb / sr Beams  10 4-5 pps S ~ 10 - 15 % error d  /d  ~ 10 - 15 % Beam time ~ 2 weeks S n, S 2n weak : High cross sections for the 1n, 2n transfer compared to elastic + to extend the transfer structure studies  more suitable range of beam E for (d,p) : E ~ 10-20 MeV/n angular momentum window, selectivity 10 134 Sn(d,p) 135 Sn @ 4.9 MeV/n  L ~ 2.5 @ 10 MeV/n  L ~ 3.2