ISOLDE – High-lights and HIE-ISOLDE Maria J. G. Borge ISOLDE-PH, CERN (Isotope Separator On-Line) IEM-CSIC, Madrid Exploring the Nuclear Landscape ISOLDE 1992 1998 2008 HIE-ISOLDE ISOLDE – High-lights and HIE-ISOLDE Maria J. G. Borge , CERN, PH-Dept

Hot Topics in Nuclear Physics Physics at the Femtometer scale

Open Questions in Nuclear Physics How are complex nuclei built from their basic constituents? strong interaction in nuclear medium • How to explain collective properties from individual nucleon behavior? collective versus individual • How do regular and simple patterns emerge in the structure of complex nuclei? symmetries LRP2010 Observables: Ground-state properties: mass, radius, J, μ, Q moments Half-lives and decay modes Transition probabilities Cross sections Main models: Shell model (magic numbers) Mean-field models (deformations) Ab-initio approaches (light nuclei)

Production of Radiactive Beams @ ISOL Facilities

ISOLDE Facility PSB upgrade (2018) intensity (2uA -> 6uA ) ISOLDE is the CERN radioactive beam facility Nuclei produced via reactions of high intensity high energy proton beam with thick and heavy targets Provides low energy or post-accelerated exotic beams intensity (2uA -> 6uA ) energy (1.4 -> 2GeV) PSB upgrade (2018)

ISOLDE at CERN LHC

Produced Nuclei: ISOLDE 45 y Experience Over 20 target materials and ionizers, depending on beam of interest operated at high temperature U, Ta, Zr, Y, Ti, Si, … 3 types of Ion-sources: Surface, Plasma, Laser > 700 nuclides of over 70 chemical elements produced Target ISOLDE today offers the largest range of available isotopes of any ISOL facility worldwide.

ISOLDE Physics Topics f(N,Z) Many beams Applied Physics Condensed matter physics and Life sciences Tailored Isotopes for Diagnosis and Therapy MEDICIS Project Many beams Good beam purity and quality Best in the World! High intensity Nuclear Physics Nuclear Decay Spectroscopy and Reactions Structure of Nuclei Exotic Decay Modes Fundamental Physics Direct Mass Measurements, Dedicated Decay Studies - WI CKM unitarity tests, search for b-n correlations, right-handed currents Atomic Physics Laser Spectroscopy and Direct Mass Measurements Radii, Moments, Nuclear Binding Energies Nuclear Astrophysics Dedicated Nuclear Decay/Reaction Studies Element Synthesis, Solar Processes f(N,Z)

Determination of the atomic properties of Astatine Determination of ionising potential Identification of new atomic transitions Comparison with atomic theory Scan of ionizing laser: converging Rydberg levels allow precise determination of the IP ISOLDE collaborates with the Short-Lived Nuclei Laboratory which is based on the ISOL facility IRIS at PNPI since 1999. Study done with 211At as the most suitable isotope ideal for short range radiation source for targeted alpha therapy. The Determination of IP of At is important to test the atomic models at the level of relativisticand coorelation effects. This tuning of the model will help in the precdition for superheavies in particular for Z = 117 that shoul dhave similar chemical properties. The identification for the 3 intermediate states was done at TRIUMF-TRILIS The most precise method to determine the IP is by the analisis of the converging levels of the rydberg states. Excitation scheme: (a): verification of the lowest 2 transition from ground state. (b)Ionization threshold. (c) Develop 3 colour scheme.Verfication of levels found with transition 224 nm (d)Scann over the rydberg states Ion detection from the alpha-decay of 119At measured in the wind-mill system. Group lead by Valentin Fedosseev, Department of Laser Spectroscopy, Institute of Spectroscopy of USSR Academy of Sciences M. Seliverstov, V. Fedoseev team IP(At) = 9.31751(8) eV Nature Com. 14May2013 DOI 10.1038

Experimental hall Beams of 30-60 keV Beams of 3 MeV/u WITCH ISCOOL Decay spectroscopy Coulomb excitation Transfer reactions Laser spectroscopy Beta-NMR Penning traps Applications: Solide state Life Science Target stations HRS & GPS Mass-sep. HRS ISCOOL RILIS REX-ISOLDE PS-Booster 1.4 GeV protons 3×1013 ppp ISOLTRAP CRIS COLLAPS NICOLE MINIBALL and T-REX WITCH Travelling setups Post-accelerated beams Collection points TAS

COLLAPS – Ne charge radii Laser spectroscopy & Massses Intrinsic density distributions of dominant proton FMD configurations Geithner et al, PRL 101, 252502 (‘08) Marinova et al, PRC84, 034313 (‘11) Drastic changes in the radious from one isotope to next that cannot be explained by the mean field approach where no drastic changes are expected. FMD = Fermionic Molecular Dynamic Model allows to include coorelations for cluster and halo states. In fact it reproduces well account well for the cluster and halo states. The binding energies, deformations, and charge radii of neon isotopes have also been calculated using the more classical mean-field approach. Among then the deformed RMF = relativistic Mean field with BCS approach of Lalazizis

ISOLTRAP: High-precision mass of 82Zn Combined ISOLDE technical know-how: neutron-converter, quartz transfer line, laser ionisation Nuclear structure: N=50 shell closure Astrophysics: r-process path Astrophysics: neutron star structure Comparison of experimental data to state-of-the-art HFB calculations. What can be seen from the plot is that although there is quite good agreement of some models for measured masses, the scatter largely in their predictions for 78Ni. HFB-D1S: it is the approach by the Bruyeres-le-Chatel group with the Gogny force (Delaroche, Hilaire, Girod et al.), which includes quadrupole correlations; - HFB-Sly4: it is the Skyrme-GCM approach of Bender, Bertsch, Heenen, which includes quadrupole correlations; - HFB-BSk17: it is the Skyrme-HFB calculation of Goriely et al. (HFB-17); - HFB-SkP: it is the Skyrme-HFB calculation of Stoitsov, Dobaczewski, Nazarewicz et al.; Astrophysics: global, microscopic HFB models (Goriely) are linked to the equation of state of a neutron star. The mass enters as an input parameter to check at what depth in the neutron-star crust what nuclei is energetically allowed to exist and is in equilibrium with the surrounding degenerate electron gas and some free neutrons. Its determination is important for modelling of the crust of neutron stars , PRL110 (2013) 04110 CERN Courier, 53, n 3, 2013 D. Rodriguez, U. Granada

The Magic Number N=32 The properties of exotic nuclei on the verge of existence play a fundamental part in our understanding of nuclear interactions. Isobars with the same energy but of slightly different mass will be reflected between the electrostatic mirrors. Their time-of-flight is proportional to the square root of the mass. Thus, after some time, the isobars will have separated in time-of-flight, which can be seen on a multi-channel plate detector. In the case of 54Cr and 54Ti, the resolving power is about 10^3, the difference in mass about 10 MeV. The spectrum in the lower right corner has the same x-axis as the one in the upper right corner. The ion counts are now depicted by the color code, the y-axis is time or number of measurement cycles. With a closed proton shell, the calcium isotopes mark the frontier for calculations with three nucleon forces from chiral effective field theory. The measured masses unambiguously establish a prominent shell closure at neutron number N=32, in excellent agreement with our theoretical calculations. These results increase our understanding of neutron-rich matter and pin down the subtle components of nuclear forces that are at the forefront of theoretical developments constrained by quantum chromodynamics Nature 498 (2013) 346

M. Beck et al., Eur. Phys. J. A47 (2011) 45 WITCH Weak Interaction Trap for Charged particles -> fundamental studies Goal: determine bn correlation for 35Ar with (a/a)stat  0.5 % Energy spectrum of recoiling ions with a retardation spectrometer Use a Penning trap to create a small, cold ion bunch June 2011 data M. Beck et al., Eur. Phys. J. A47 (2011) 45 M. Tandecki et al., NIM A629 (2011) 396 S. Van Gorp et al., NIM A638 (2011) 192

REX-ISOLDE Total efficiency : 1 -10 % Tested A/q = 2 1+ to A/Q = 3 – 4.5 Tested A/q = 2 Ions are cold in the large aceptance rex-trap to effectively enter in the Electron beam ion source that produce a charge breeding between 3 al 4.5. last year the A/Q ratio 2 was successfully proved. The 4-rod-RFQ is designed to accelerate radioactive ions with a charge-to-mass ratio larger than 1/4.5 from 5 keV/u to 300 keV/u . The RF Quadrupole field provides transverse focusing for the low energy ions while a modulation of the four rods performs a smooth bunching and acceleration of the injected 100 µs bunch. The IH-Structure (IHS) [8] is a compact cavity containing separated regions of acceleration and focusing, including a triplet of quadrupoles and a section of drift tubes operating as a re-buncher, boosting the beam from 0.3 MeV/u to an energy value between 1.1 and 1.2 MeV/u, by providing an effective voltage of up to 4.2 MV. The whole structure has 20 gaps and a total length of 1.5 m.

Halo Nuclei & Reactions 7Be 8Be 9Be 10Be 11Be 12Be 14Be Halo Nuclei & Reactions 6Li 7Li 8Li 9Li 10Li 11Li 3He 4He 6He 2n-halo 1H 2H Common “Structural” properties Rather inert core plus one or two barely unbound extra neutrons Extended neutron distribution, large “radius”. “halo” Very few excited states –if any. n Reaction properties at near-barrier energies: Is the Optical Model able to describe the scattering of the halo systems ?  Strong absorption in elastic channel Large cross section for fragmentation They are easily polarizable. Reaction mechanisms and Nuclear effects of halo nuclei need to be understood They are easily polarizable: - In the scattering process the forces between target and core/ halo are different  distortion effects  e.g. Coulomb dipole polarizability Dobrovolsky et al, NPA766 (2006) 1

Elastic scattering of halo nuclei near the Coulomb barrier 10,11Be+64Zn 10Be+64Zn 11Be+64Zn Di Pietro et al. Phys. Rev. Lett. 105,022701(2010) Catania, IEM-CSIC, Huleva, Sevilla Collaboration CDCC calculations Experimental elastic cross section. reproduced only taking into account coupling to continuum via the Coulomb and nuclear interactions

Scattering of 11,9Li on 208Pb around the Coulomb Barrier Elastic Scattering ECM = 23.1 MeV below Coulomb Barrier Competing process with Elastic Scattering for loosely bound systems 9Li Direct Breakup 2n-Transfer 11Li ECM = 28.3 MeV @ the Coulomb Barrier 9Li Scattering process dominated by: - Dipole couplings (coulomb + nuclear) Coupling to continuum Good description in a 4-body model Cubero et al, PRL109 (2012) 262701 IEM-CSIC, Huelva, Seville Collaboration 11Li 18

Why to study the N=Z 72Kr Nucleus? Nuclear structure: Shape coexistence in the mass region was first proposed for 72Se [Ham74]. 72Kr ground state is predicted to be oblate [Dic72] and [Naz85]. First excited 0+ state in 72Kr found to be a shape isomer [Bou03]. Possibility of study np-pairing effects as 72Kr belongs to N=Z line. [Ham74] J.H. Hamilton et al., Phys. Rev. Lett. 32, 239 (1974) [Dic72] F. Dickmann et al., Phys.Lett. 38B, 207 (1972) [Naz85] W. Nazarewicz et al., Nucl. Phys. A435, 397 (1985) [Bou03] E. Bouchez et al., Phys. Rev. Lett. 90, 082502 (2003) Nuclear astrophysics: 72Kr “waiting point" in rp process. 73Rb is unbound β decay competes with 2p capture. rp-process in N=Z nuclei & A=70-80 region

Coulomb excitation of 72Kr Use of submicron Y203 material for target => Yield increase x 10 Coulex Spectra - number of counts in 710 keV peak depends on the shape of 72Kr Oblate 72Kr expected The technique Doppler Corrected for 104Pd target excitation Both theory and exp agree that is the unique case with oblate low level states and prolates high excites states. Nevertheless there is no evidence of the sign of deformation of the 2+ state Doppler Corrected for 72Kr projectile excitation: 150 counts in 710 keV line

TAGS @ISOLDE: The case of 72Kr Conversion electron studies to determine the multiplicities of the low gamma transitions B(GT) obtained by measuring the intensity of the full gamma de-excitation cascade from each fed level to the ground state. P. Sarriguren, Phys. Rev. C 79, 044315 (2009) Briz, ISOLDE Workshop 2012 IEM-CSIC, Strasbourg, Surrey, Valencia The B(GT) distribution favours oblate deformation!

Searching for pear-shaped nuclei at ISOLDE λ = 2 Octupole correlations enhanced at numbers: Z or N=34, 56, 88, and N= 134.  Observed Z≈88 & N≈134 Coulomb excitation to directly access E3 transition strengths B(E3) ≳ 30 s.p.u. gives significant β3 1/3 of all nuclei are bound mostly if they are settle away sphericity into deformed elongated quadrupole shape. Quantum correlations between nucleons are expected occasionally to favour more exotic shapes. These special nuclei serve to test these specific correlations. In quadrupole deofrmed experimental observables are the E2 transitions and Q-moments In case of pear shapè there are additional E1 and E3 moments. While the first are very small the E3 are collective > 10 single particle units. So far the E3 moment has only been determined for 226Ra. Particular correlations arise when particular momentum J are near the Fermi surface. Excitation of coherent correlated pairs of nucleons between these states drives the whole nucleus into a pear shape. Strong octupole correlation leading to pear shapes can arise when nucleons near the Fermi surface occupy states of opposite parity with orbital and total momentum differeing in 3h. In these cercunstances interleave parity bands with enhanced E1 transitions. Microscopically driven... Intruder orbitals of opposite parity and ∆J, ∆L = 3 close to the Fermi level

L. P. Gaffney, et al. (2013). Nature, 497(7448), 199–204. doi:10 L. P. Gaffney, et al. (2013). Nature, 497(7448), 199–204. doi:10.1038/nature12073 Hangout with CERN: Going pear-shaped (http://www.youtube.com/watch?v=x8Jdu9O2RhU&feature=em-uploademail) MORE than 1000 viewers Different of cross section with different Z targets is apparent Gamma corrected by doppler shift and only recorded if the recoiling nucleus was detected simultaneously. Spectra revael strong population of ground state band of positive parity and octupole band of negative parity. GOSIA code is used to deduced the matrix elements. The values of E2 and E3 intrinsic moments are given are given the dashed lines define the average. One can sse that Q3 is large for 224Ra and comparable to 226Ra

Physics program @ REX REX-ISOLDE started in 2001 72 different beams already used at REX- ISOLDE of 700 available! 222,224Ra; 220,222Rn Probing Pear Shape Nature 497 (2013)199 184,186,188Hg Probing shape coexistence 20 40 82 50 82 The Limitations of REX-ISOLDE (E 3.1 MeV/u) Very limited energy flexibility Operation restricted to pulsed mode Bunch length is not flexible Extension to higher energy is difficult 110Sn; Cederkäll, PRL 2007 106,108Sn, Cederkäll, PRL 2008 50 122,124,126Cd 138,140,142,144Xe 140,148,150Ba Evolution of collectivity around 132 Sn 70Se, shape coexistence, Hurst PRL 2007 96Sr, 88Kr, 92Kr 28 67,69,71,73Cu, Stefanescu et al., PRL 2008 68,70Cu, isomeric 68Cu, Stefanescu , PRL 2007 74,76,78,80Zn Probing large scale shell model, Van der Walle, PRL2007 30,31,32Mg, Niedermaier PRL2005, H. Scheit d(30Mg,p)31Mg, K. Wimmer, PRL 2010 20 Halos & clusters d(8Li,p)9Li*; d(9Li,p)10Li…

Near Future: HIE-ISOLDE project Approved Dec 2009 Offically started Jan 2010 Yacine Kadi project Leader Budget 40 M$ Energy Upgrade: The HIE-ISOLDE project construction of the SC LINAC to upgrade the energy of the post-accelerated radioactive ion beams to 5.5 MeV/u in 2015 and 10 MeV/u by 2017 Intensity Upgrade: The design study for the intensity upgrade, also part of HIE-ISOLDE, started in 2011, and addresses the technical feasibility and cost estimate for operating the facility at 10 kW once LINAC4 and PS Booster are online. The HIE-ISOLDE project concentrates on the construction of the SC LINAC and associated infrastructure in order to upgrade the energy of the post-accelerated radioactive ion beams to 5.5 MeV/u in 2015 and 10 MeV/u by 2017

Physics addressed with HIE-ISOLDE / IS564 Study of the unbound proton-rich nucleus 21Al with resonance elastic and inelastic scattering using an active target (USC, IEM, MAYA Collaboration)

Experiment To measure resonant elastic, 20Mg(0+), and inelastic, 20Mg(2+), scattering using MAYA to determine energy, spin and parity of the 21Al excited states. There are many goals, the 20Mg(p,p)20Mg reaction will be used to scan the states coupled to the 20Mg(0+) state while the 20Mg(p,p’)20Mg will investigate the states coupled to the 20Mg(2+) core. Recoil protons from the target will give information on the excitation function of the compound nucleus and the total path of the beam and fragment will be used to select the inelastic channel. Spectroscopic properties of the low-lying states will be obtained in a R-matrix analysis of the excitation Recoil protons E and θ -> Excitation function of the compound nucleus.. Total path -> Select the inelastic channel and contamination. • The location of the 1/2+ state differs between the models • The ground state 5/2+ would be seen if closer to J. Holt’s predictions • Narrow resonances are expected above the 20Mg(2+) threshold function for a given angular range.

Thanks for your attention ! Summary and outlook The future of ISOLDE is bright. It will restart in June 2014 with the low energy program. With more than 40 year of operation ISOLDE remains as the pioneer ISOL-installation both at the level of designing new devices and production of frontier Physics. Post accelerated beams up to 5.5 MeV/u for the wide range of nuclei produced at ISOLDE will be available from Autumn 2015. HIE-ISOLDE will be the only next-generation radioactive beam facility (as identified by the NuPECC LRP) available in Europe in 2015, and the most advanced ISOL facility world-wide. Welcome to propose challenging experiments! Thanks for your attention !