Task10 : Physics & Instrumentation Subtask: Single Particle & Collective Properties ( Contributors: Angela Bonaccorso, Roy Lemmon, Valerie Lapoux, Yorick Blumenfeld.) Check limits of validity of mean field and single particle concepts for medium to heavy mass nuclei with exotic Z/N and particle separation energy S n ~10 MeV. Also the long range and short range correlations can vary, as a consequence of the isospin dependence of the N-N interaction. Study interior part of wave functions of nucleons and clusters. Un example of study of new reaction mechanisms: Full kinematics reconstruction deep inelastic experiments.

slightly I. Full kinematics reconstruction slightly deep inelastic experiment Heavy target ( 208 Pb), medium mass neutron rich projectile (A=30-60). Measure knockout (nuclear breakup) of neutron, proton and  Projetile and target  -rays plus neutrons from the target to reconstruct excitation energy. Check peripherality of the reaction by impact parameter identification via angle measurement (semiclassical system, large Sommerfeld paramether) in an event by event reconstruction. Width of core momentum distribution larger for smaller (core-target) impact parameters. Reduction of spectroscopic factors values and of ANC ?

II. One-proton removal reactions and (d, 3 He) transfer reactions using beams of neutron-rich Pb isotopes from EURISOL will consitute another key experiment within this programme. Explore how the spectroscopic factors and occupancy of the 3s 1/2 proton orbital changes in the heavy neutron-rich Pb isotopes. R.Lemmon Daresbury Laboratory, UK.

III: Instrumentation R.Lemmon Daresbury Laboratory, UK.

drip-lines & properties in the vicinity of new doubly magic nuclei ? Nuclear densities ? Halo shapes ? Explorations of the nuclear landscape using EURISOL beams Explorations of the nuclear landscape using EURISOL beams doubly magic stable nuclei doubly magic unstable nuclei ? ? Zr Sn 78 Ni neutron drip-line known up to Z=8 ( 24 O )… EURISOL TYPICAL EXPERIMENTS : Ne(p,p’) (p,d) (p,t) (d, 3 He) 78 Ni(p,p’) (N=50) Ca (N=40,50) 104 Se (Z=34, N=70). V. Lapoux CEA-Saclay DSM/DAPNIA/SPhN

Tool to probe proton and neutron densities: (p,p’) scattering Elastic scattering sensitive to the matter rms Inelastic scattering : sensitive to the shape of the density distribution 6 He(p,p) 6 He(p,p’) 6 He(2+) 6 A.MeV A. Lagoyannis et al., PLB 518 (2001) 27 Ganil /SISSI MUST data 6 He 3-body density 8 He 5-body density rms = 2.5  0.1 fm S 2n = He 1.8 MeV (p,p) not enough for testing radial shapes of densities, through (p,p’) we obtain not only excitation but also features of the density profiles >>> Specific tools to study unbound states of weakly-bound nuclei: direct reactions in inverse kinematics and missing mass method. V. Lapoux CEA-Saclay DSM/DAPNIA/SPhN

Going closer to driplines with higher intensities: openes new physics fields Z N spectroscopy of neutron-rich around magic numbers N=28, N=40 (new possible magic) N=50, N=70 (new) Ex : 34,36 Ne, 38 Ne (if not unbound), Ca, 78 Ni 104 Se (Z=34, N=70) BEAMSPROBES Neutron-rich isotopes close to the drip-lines: 24 O, 30 Ne (p,p’) Required intensities I > 10 3 /s Chains O ( 24 O), Ne + Mg, Si, S, Ar : we need to complete the studies of the neutron excitation done for the 1 st generation of RIBS GOALS : Structure and spectroscopy close to or at the drip-lines (p,p’) on a wide angular range Required intensities I > 10 4 /s d, 3 He) ( d, 3 He) (d,2p) reactions Knock-out Evolution of neutron excitation Mn vs N along isotopic chains Exotic shapes and densities One-particle state Spectroscopic factors Skin and halos Soft collective modes Spectroscopy Low-lying states INFORMATION. V. Lapoux CEA-Saclay DSM/DAPNIA/SPhN

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 At the drip-lines : Low S n, S 2n, S 4n, (below 10MeV) : most of the excited states are unbound Check: alpha-neutrons correlations Needs LCP and neutron devices granularity & efficiency. V. Lapoux CEA-Saclay DSM/DAPNIA/SPhN

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 2016 Wishes for Coupled Detection devices. V. Lapoux CEA-Saclay DSM/DAPNIA/SPhN

Means BEAMS OF RARE ISOTOPES Today 1/s, EURISOL /s Means DIRECT PROBES i.e p & d targets, + Polarized p,d DIRECT REACTIONS target: CH 2 or cryogenic H 2 Light charged particle (LCP) detection  -ray detection: future AGATA exotic beam A Z identification Beam Tracking Devices BTD A+1 Z p E inc ~ MeV/n Nearly (~90%) pure beam Complete set-up for direct reactions on proton and deuton targets. V. Lapoux CEA-Saclay DSM/DAPNIA/SPhN

The GMR at EURISOL ( Y. Blumenfeld, G. Colo`, E. Kahn )

CONCLUSION FROM THE ISGMR Fully self-consistent calculations of the ISGMR using Skyrme forces lead to K ∞ ~ MeV. Relativistic mean field (RMF) plus RPA: lower limit for K ∞ equal to 250 MeV. It is possible to build bona fide Skyrme forces so that the incompressibility is close to the relativistic value. → K ∞ = 240 ± 10 MeV. To reduce this uncertainity one should fix the density dependence of the symmetry energy. COLO, Trento

Detection constraints GMR must be measured around 0 deg. in the CM frame Needs for a high efficiency detector With low energy threshold GQR contribution is evaluated from larger  CM angles and subtracted Test the detection setup on 56 Ni : heaviest N=Z nuclei ever studied for the GMR  CM (deg.) 10

Kinematics 56 Ni( ,  ’) at 33MeV/u GMR GQR,5

The MAYA detector 4  solid angle coverage Low energy threshold (~200 keV) Thick gazous He target (28 cm) Measure the angle and the energy of the recoiling  by trajectory reconstruction Suppression of the beam signal with two plates around the beam Resolution : 50 keV in energy 4° lab angle  R&D : ACTAR JRA (EURONS)

GRAPA R&D on charged particle detectors Detectors Electronics Data Acquisition

Developments necessary… Improvements of PSD performance through nTD Si, with segmentation. Development of 5cm thick planar segmented Ge detectors; mounting of Si-Ge telescope with minimum dead layers. Explore alternatives to Ge (CdZnTe…) ASIC Electronics –High dynamic range preamplifiers –CFDs –Fast digital pulse sampling Cryogenic H and He targets; polarized targets