V. Lapoux DAPNIA/SPhN EURISOL Jan. 06 Physics & Instrumentation Trento, 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

V. Lapoux DAPNIA/SPhN EURISOL 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 ?

V. Lapoux DAPNIA/SPhN EURISOL 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, (’05) Modification of the usual shell structure new magic numbers Neutron- rich 20,22 O

V. Lapoux DAPNIA/SPhN EURISOL Jan. 06 Prototype of (p,p’) & direct reactions at low energy : 8 He(p,p’) SPIRAL beam MUST+CATS structure of 8 He :  + 4n? S n =2.5 S 4n =3.1 S 2n = 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 Ganil, PLB 518, 27 (‘01). 6 He : 2n-halo 8 He : neutron-skin Resonances of 7,8 He Exotic structures

V. Lapoux DAPNIA/SPhN EURISOL Jan He 8 He excitation energy spectrum 7 He 1n transfer : 8 He(p,d) 7 He g.s He 2n Transfer 8 He(p,t) 6 He 8 He 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 ± 0.14 MeV Γ = 0.3 ± 0.2 MeV ? 5.4 ± 0.5 MeV Γ = 0.3 ± 0.5 MeV

V. Lapoux DAPNIA/SPhN EURISOL Jan. 06 Nuclear landscape towards the drip-lines N 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 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

V. Lapoux DAPNIA/SPhN EURISOL Jan. 06 Nuclear landscape towards the drip-lines N Z 4 He 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 Tarasov97 Sakurai97 Notani02, Lukyanov02 43 Si

V. Lapoux DAPNIA/SPhN EURISOL 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 = O N = 16 N = 8 16 N=16  Learnt from 1 st generation of RIBs (1h11/2 - ) (f7/2)

V. Lapoux DAPNIA/SPhN EURISOL Jan ? Zr Sn 78 Ni 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

V. Lapoux DAPNIA/SPhN EURISOL 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

V. Lapoux DAPNIA/SPhN EURISOL 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 ? Ca ?) or rare at present ( 24 O few/s at GANIL, RIKEN) with EURISOL : counting rates less or around /s Will all our beams be as intense as we believe ??? 2016 : 2016 : starting EURISOL beams

V. Lapoux DAPNIA/SPhN EURISOL 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  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), Ca, 104 Se (Z=34, N=70) Far..far away

V. Lapoux DAPNIA/SPhN EURISOL Jan S 2n =7.91 S n = Kr 6? MeV ? Calc : M.V. Stoitsov, et al., Phys. Rev. C68, (‘03) Data AME S 2n =8.5 S n = Kr ? 0.67 MeV Similar trend for all neutron-rich EURISOL beams : few bound states

V. Lapoux DAPNIA/SPhN EURISOL Jan 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 MUST MUr à STrips 2

V. Lapoux DAPNIA/SPhN EURISOL 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 ?

V. Lapoux DAPNIA/SPhN EURISOL Jan 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

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

V. Lapoux DAPNIA/SPhN EURISOL 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 15 cm Intrinsic DE (Si) ~ 50 keV DE resolution (with thin target ~ 1mg/cm 2 ) ~ keV Precision on centroid, bound states ~ 30 keV resonant states ~ 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

V. Lapoux DAPNIA/SPhN EURISOL 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

V. Lapoux DAPNIA/SPhN EURISOL 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 9 MeV/n 2016 Wishes for Coupled Detection devices

V. Lapoux DAPNIA/SPhN EURISOL Jan. 06 EURISOL : specific experiments and beams Exotic structure at the neutron drip-line : Ex : 24 O 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)

V. Lapoux DAPNIA/SPhN EURISOL Jan. 06 EURISOL : specific experiments and beams Present (1 st generation) intensities : few part/s Needed : (at least) /s 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 ?

V. Lapoux DAPNIA/SPhN EURISOL Jan. 06 conclusions Means BEAMS OF RARE ISOTOPES Today 1/s, EURISOL /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 ~ MeV/n Nearly (~90%) pure beam

V. Lapoux DAPNIA/SPhN EURISOL 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

V. Lapoux DAPNIA/SPhN EURISOL Jan 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, (’05) précision centroïde ~ 30keV  E* = 750 keV réactions de référence

V. Lapoux DAPNIA/SPhN EURISOL Jan. 06 A Z(p,d) A-1 Z Q = S n (A+1,Z)-S n (d) = S n (A+1,Z) MeV Q(p,d)= S n (d)-S n (A,Z) = S n A Z(p,t) A-2 Z Q(p,t)=S 2n (t)-S 2n (A,Z) = –S 2n Q 8 He(p,t) = 6.34 Ex : Q 8 He(p,d) = S n =2.5 S 4n =3.1 S 2n = He 3.6MeV ? A Z(d,p) A+1 Z Q [ 96 Kr(p,d) ]~ - 2.8MeVQ [ 96 Kr(p,t) ]~ 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 (~ 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  pps S ~ % error d  /d  ~ % 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 ~ MeV/n angular momentum window, selectivity Sn(d,p) MeV/n  L ~ 10 MeV/n  L ~ 3.2