Maria J G Borge ISOLDEPH CERN Isotope Separator
Maria J. G. Borge ISOLDE-PH, CERN (Isotope Separator On-Line) IEM-CSIC, Madrid n i r lo p x E HIE-ISOLDE Maria J. G. Borge , CERN, HIE-ISOLDE PH-Dept ISOLDE – High-lights and 8 h t g 8 9 9 1 200 L r ea l c u 992 1 N e ISOLDE s d an e p ca
Hot Topics in Nuclear Physics at the Femtometer scale 2
Open Questions in Nuclear Physics How are complex nuclei built from their basic constituents? Østrong interaction in nuclear medium • How to explain collective properties from individual nucleon behavior? Øcollective versus individual LRP 2010 • How do regular and simple patterns emerge in the structure of complex nuclei? Observables: Øsymmetries 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) 3
Production of Radiactive Beams @ ISOL Facilities 4
ISOLDE Facility 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 PSB upgrade (2018) intensity (2 u. A -> 6 u. A ) energy (1. 4 -> 2 Ge. V) 5
ISOLDE at CERN LH C 6
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. 7
ISOLDE Physics Topics Many beams Good beam purity and quality Best in the World! High intensity Nuclear Physics Applied Physics Condensed matter physics and Life sciences Tailored Isotopes for Diagnosis and Therapy MEDICIS Project 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 f(N, Z) Nuclear Astrophysics Dedicated Nuclear Decay/Reaction Studies Element Synthesis, Solar Processes 8
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. M. Seliverstov, V. Fedoseev team IP(At) = 9. 31751(8) e. V Nature Com. 14 May 2013 DOI 10. 1038 9
Experimental hall Decay spectroscopy Coulomb excitation Transfer reactions Laser spectroscopy Beta-NMR Penning traps Applications: Ø Solide state Ø Life Science Beams of 30 -60 ke. V Beams of 3 Me. V/u Target stations HRS & GPS PS-Booster 1. 4 Ge. V protons Mass-sep. HRS WITCH REX-ISOLDE 3× 1013 ppp ISCOOL RILIS Travelling setups NICOLE Post-accelerated beams Collection points MINIBALL and T-REX Travelling setups COLLAPS CRIS ISOLTRAP 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, PRC 84, 034313 (‘ 11) 11
ISOLTRAP: High-precision mass of 82 Zn 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 Its determination is important for modelling of the crust of neutron stars , PRL 110 (2013) 04110 CERN Courier, 53, n 3, 2013 12 D. Rodriguez, U. Granada
The Magic Number N=32 Nature 498 (2013) 346 13
WITCH Weak Interaction Trap for Charged particles -> fundamental studies Goal: determine bn correlation for 35 Ar with ( a/a)stat 0. 5 % Ø Energy spectrum of recoiling ions with a retardation spectrometer Ø Use a Penning trap to create a small, cold ion bunch June 2011 data M. Beck et al. , Eur. Phys. J. A 47 (2011) 45 M. Tandecki et al. , NIM A 629 (2011) 396 14 Gorp et al. , NIM A 638 (2011) 192 S. Van
REX-ISOLDE Total efficiency : 1 -10 % 1+ to A/Q = 3 – 4. 5 Tested A/q = 2 15
Halo Nuclei & Reactions 7 Be 8 Be 9 Be 10 Be 11 Be 12 Be 6 Li 3 He 4 He 1 H 2 H n 7 Li 8 Li 14 Be 9 Li 10 Li 11 Li 6 He alo 2 n-h Common “Structural” properties p p p Rather inert core plus one or two barely unbound extra neutrons Extended neutron distribution, large “radius”. “halo” Very few excited states –if any. 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. Dobrovolsky et al, NPA 766 (2006) 1 Reaction mechanisms and Nuclear effects of halo nuclei need to be understood
Elastic scattering of halo nuclei near the Coulomb barrier 10, 11 Be+64 Zn 10 Be+64 Zn 11 Be+64 Zn 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 17
Scattering of 11, 9 Li on 208 Pb around the Coulomb Barrier Elastic Scattering ECM = 23. 1 Me. V below Coulomb Barrier 9 Li Competing process with Elastic Scattering for loosely bound systems Direct Breakup 11 Li 2 n-Transfer ECM = 28. 3 Me. V @ the Coulomb Barrier 9 Li Scattering process dominated by: - Dipole couplings (coulomb + nuclear) - Coupling to continuum - Good description in a 4 -body model 11 Li Cubero et al, PRL 109 (2012) 262701 IEM-CSIC, Huelva, Seville Collaboration 18 18
Why to study the N=Z 72 Kr Nucleus? Nuclear structure: o Shape coexistence in the mass region was first proposed for 72 Se [Ham 74]. o 72 Kr ground state is predicted to be oblate [Dic 72] and [Naz 85]. o First excited 0+ state in 72 Kr found to be a shape isomer [Bou 03]. o Possibility of study np-pairing effects as 72 Kr belongs to N=Z line. [Ham 74] J. H. Hamilton et al. , Phys. Rev. Lett. 32, 239 (1974) [Dic 72] F. Dickmann et al. , Phys. Lett. 38 B, 207 (1972) [Naz 85] W. Nazarewicz et al. , Nucl. Phys. A 435, 397 (1985) [Bou 03] E. Bouchez et al. , Phys. Rev. Lett. 90, 082502 (2003) Nuclear astrophysics: o 72 Kr rp-process in N=Z nuclei & A=70 -80 region “waiting point" in rp process. 73 Rb is unbound o β decay competes with 2 p capture. 19
Coulomb excitation of 72 Kr Use of submicron Y 203 material for target => Yield increase x 10 Oblate 72 Kr expected Coulex Spectra - number of counts in 710 ke. V peak depends on the shape of 72 Kr Doppler Corrected for 104 Pd target excitation The technique Doppler Corrected for 72 Kr projectile excitation: 150 counts in 710 ke. V line 20
TAGS @ISOLDE: The case of 72 Kr o Conversion electron studies to determine the multiplicities of the low gamma transitions o 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) 21 distribution favours oblate deformation!
Searching for pear-shaped nuclei at ISOLDE Coulomb excitation to directly access E 3 transition strengths λ=2 B(E 3) ≳ 30 s. p. u. gives significant β 3 Octupole correlations enhanced at numbers: Z or N=34, 56, 88, and N= 134. Observed Z≈88 & N≈134 Microscopically driven. . . Intruder orbitals of opposite parity and ∆J, ∆L = 3 close to the Fermi level 22
L. P. Gaffney, et al. (2013). Nature, 497(7448), 199– 204. doi: 10. 1038/nature 12073 Hangout with CERN: Going pear-shaped (http: //www. youtube. com/watch? v=x 8 Jdu 9 O 2 Rh. U&feature=emuploademail) MORE than 1000 viewers 23
Physics program @ REX-ISOLDE started in 2001 72 different beams already used at REX- ISOLDE of 700 available! 20 40 82 50 222, 224 Ra; 220, 222 Rn 184, 186, 188 Hg Probing Pear Shape Nature 497 (2013)199 Probing shape coexistence 82 The Limitations of REX-ISOLDE (E 3. 1 Me. V/u) § § § Evolution of collectivity § Extension to higher energy is difficult Xe Se, shape coexistence, Hurst PRL 2007 around Sn 110 Sn; Cederkäll, PRL 2007 Very limited energy flexibility 106, 108 Sn, Cederkäll, PRL 2008 Operation restricted to pulsed mode 50 122, 124, 126 Cd Bunch length is not flexible 138, 140, 142, 144 70 96 Sr, 88 Kr, 92 Kr 28 132 140, 148, 150 Ba 74, 76, 78, 80 Zn Probing large scale shell model, Van der Walle, PRL 2007 67, 69, 71, 73 Cu, Stefanescu et al. , PRL 2008 68, 70 Cu, isomeric 68 Cu, Stefanescu , PRL 2007 30, 31, 32 Mg, 20 Niedermaier PRL 2005, H. Scheit d(30 Mg, p)31 Mg, K. Wimmer, PRL 2010 Halos & clusters d(8 Li, p)9 Li*; d(9 Li, p)10 Li… 24
Near Future: HIE-ISOLDE project • • Energy Upgrade: The HIE-ISOLDE project construction of the SC LINAC to upgrade the energy of the postaccelerated radioactive ion beams to 5. 5 Me. V/u in 2015 and 10 Me. V/u by 2017 25 Approved Dec 2009 Offically started Jan 2010 Yacine Kadi project Leader Budget 40 M$ 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 k. W once LINAC 4 and PS Booster are online.
Physics addressed with HIE-ISOLDE / IS 564 Study of the unbound proton-rich nucleus 21 Al with resonance elastic and inelastic scattering using an active target (USC, IEM, MAYA Collaboration) 26
Experiment To measure resonant elastic, 20 Mg(0+), and inelastic, 20 Mg(2+), scattering using MAYA to determine energy, spin and parity of the 21 Al excited states. 27
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 Me. V/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 Nu. PECC LRP) available in Europe in 2015, and the most advanced ISOL facility world-wide. Welcome to propose challenging experiments! Thanks for your attention ! 28
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