The DESIR facility at SPIRAL 2 DESIR Dsintgration

The DESIR facility at SPIRAL 2 DESIR: Désintégration, excitation et stockage d’ions radioactifs (Decay, excitation and storage of radioactive ions) • Result of a SPIRAL 2 workshop in July 2005 on ISOL beams at SPIRAL 2: - Decay spectroscopy: Maria José Garcià Borge (Madrid) François Le Blanc (IPN Orsay) Gerda Neyens (KU Leuven) Paul Campbell (Manchester) Dave Lunney (CSNSM) Oscar Naviliat-Cuncic (LPC Caen Frank Herfurth (GSI) - LASER spectroscopy: - Atom and ion traps: • Spokes-person: Bertram Blank • GANIL liaison: Jean-Charles Thomas Bertram Blank, SAC SPIRAL 2, 19 -20 October 2006

pps • close to stable beam intensities for exotic nuclei • much higher intensities than at ISOLDE or Oak Ridge • not too far from EURISOL intensities • key nuclei like 78 Ni, 100 Sn, 132 Sn with high intensities • fusion-evaporation to access high-spin states pps Why another ISOL facility? pps A A

Conclusions of the SPIRAL 2 Workshop (july 2005): Low energy RIB 1. A new experimental area of about 1500 m 2 located at the ground floor, dedicated to the experiments with low-energy beams from SPIRAL 2 is strongly requested. The new building includes areas for the experimental equipments, acquisition and control rooms. 2. A High Resolution mass Separator (HRS) with a resolution of M/ M>5000 with a dedicated identification station is absolutely necessary. A separation scheme Low Resolution mass separator → RFQ cooler → HRS is proposed. 3. The low energy radioactive beams should be available for experiments already at the beginning of the operation of SPIRAL 2. The physics program requires both neutron-rich and neutron-deficient beams. 4. More than one production target – ion source station is required to ensure flexible schedule and a possibility for fast change of the mass of radioactive beams. 5. An extension of the current LIRAT beam line in order to take full advantage of the SPIRAL 1 beams is proposed.

DESIR physics program v Decay spectroscopy - decay properties and nuclear structure studies - particle-particle correlations, cluster emission, GT strength - exotic shapes, halo nuclei v Laser spectroscopy - static properties of nuclei in their ground and isomeric states - deformation v Fundamental interactions - CVC hypothesis, CKM matrix unitarity via 0+ transitions - exotic interactions (scalar and tensor currents) - CP (or T) violation with e. g. Radium v Solid state physics and other applications

SPIRAL 2 LAYOUT GANIL facility LIRAT Production building DESIR LINAG

Underground J. C. Thomas, GANIL

DESIR: Ground-floor LUMIERE trap neutrons buncher Ion sources x TIOL MOT general purpose spec BES laser Paul trap

Beam handling: methods Magnetic separation (HRS) A. Jokinen, JYFL PENNING TRAP

Beam handling: RFQ cooler and buncher RF RFQ-cooler: 3 p mm mrad, 0. 5 e. V, 10 ms, 60 % D. Lunney et al. , CSNSM

Beam handling: Implementation F. Varenne, GANIL

Summary of decay spectroscopy experiments: The BESTIOL facility (BEta decay STudies at the SPIRAL 2 Is. OL facility) • Decay studies with halo nuclei • Clustering studies in light nuclei • Super-allowed decays and the standard model of electro-weak interaction • Angular correlation measurements and standard model of electro-weak interaction • Cases of astrophysical interest • New magic numbers • Transition from Order to Chaos • Shape coexistence, deformation and Gamow-Teller distribution • High-spin isomers • Test of isospin symmetry combined with charge exchange reactions • Beta-delayed charged-particle emission: e. g. proton-proton correlation

Decay properties of exotic nuclei Ø Global properties • Short half-lives ( 10 ms) 1916 Rutherford & Wood [Philos. Mag. 31 (1916) 379] 1963 Barton & Bell identified 25 Si as p emitter • High Qb values • Low Sp/n values -delayed particle emission Ø Very Selective probe • Selection rules: • Fermi: T=0 ; J=0 ; pf = pi • Gamow-Teller: T=0± 1; J=0± 1 ; pf = pi • Reduced transition probability: E, Level density Spin, Isospin -decay properties

Search for exotic interactions e+ q e nucleus • b-n angular correlation requires to measure the recoil ion + particle • within the SM x : Fermi fraction; r : GT/F mixing ratio • beyond the SM a contains quadratic S and T contributions O. Naviliat-Cuncic et al. , LPC Caen

Search for exotic interactions: Production and preparation of 6 He candidate: (pure GT transition) deduce bn angular correlation from measurement of b-recoil (recoil with very low energies < 1 ke. V) 6 He+ production at SPIRAL cooling in H 2 gas / bunching trapping/measuring LIRAT low energy beam line O. Naviliat-Cuncic et al. , LPC Caen

Search for exotic interactions: Setup and first results • TOF of ions extracted from trap beta telescope PM plastic scintillator DSSSD beam monitor m. CP 6 He+ • first time difference for -decay RF ON/OFF (V-A theory) 10 cm m. CP recoil ion detector O. Naviliat-Cuncic et al. , LPC Caen

CVC, CKM, exotic currents: 0+ decays = 3073. 5 (12) s (1) 3074. 4 (12) s (1, 2) Measurements: - Q value - T 1/2 - branching ratios Vud 0+0+ = 0. 9738(4) (1) 0. 9736(3) (1, 2, 3) Vus. K = 0. 2200(23) (PDG) 0. 2254(21) (4) Vub. B = 0. 00367(47) (PDG) 0. 9987(11) (~ 2 shift) (1) Towner and Hardy, PRL 94 (2003) 092501, PRC 71 (2005) 055501 (2) Savard et al. , PRL 95 (2005) 102501 (3) Marciano & Sirlin, PRL 96 (2006) 032002 (4) E 865, KTe. V, NA 48, KLOE (PDG) Particle Data Group, S. Eidelman et al. , PLB 592 (2004) 1

0+ decays: Physics output 1. 1. Vud matrix element ( test of unitarity) 2. 2. test of CVC (constancy of Ft 0+ 0+ values) Ad 3: Left Right Symm. -models W 1 = WL cos - WR sin W 2 = WL sin + WR cos = m 12 / m 22 3. right-handed currents: -0. 0005 < < 0. 0015 (90% C. L. ) 4. scalar currents: 0. 011 Ad 4: scalar currents N. Severijns et al.

0+ decays: Future studies • further improve results for “classical” isotopes • determine Ft-values for new isotopes of interest: Tz = -1 isotopes: 18 Ne, 22 Mg, 26 Si, 30 S, 34 Ar, 38 Ca, 42 Ti Tz = 0 isotopes: 62 Ga, 66 As, 70 Br, 74 Rb, 78 Y, 82 Nb, 86 Tc, 90 Rh, 94 Ag, 98 In à stronger limits for new physics à test and improve reliability of isospin corrections à extend CVC test to higher mass region needs: - relatively pure beams ( 103 at/s) of ‘classical’ and new 0+ isotopes - precision spectroscopy techniques (for t 1/2 and BR) - Penning traps (mainly for QEC/mass)

Study of GT strength via -delayed proton decay: 21 Mg Theory Counts Experiment 21 Mg Energy (ke. V) J. C. Thomas

Mirror symmetry studies + : p → n + e+ + - : n → p + e- + E. C. : p + e- → n + + - ft ft n p Ø Allowed Gamow-Teller transitions (log(ft)<6) g 17 couples of nuclei g 46 mirror transitions Average asymmetry : 11 (1) % in the 1 p shell (A<17) 0 (1) % in the (2 s, 1 d) shell (17<A<40) J. C. Thomas, J. Giovinazzo et al. (GANIL/CENBG) = nuc + SCC = 4. 8 (4) %

Search for p-p correlation in 2 p decay Two possible decay schemes: • sequential → no angular or energy correlation • 2 He type decay → angular and energy correlation pairing correlations, nucleon-nucleon interaction, final-state interactions…. Possible candidates: 22 Al, 23 Si, 26 P, 27 S, 31 Ar, 35 Ca, 43 Cr, 50 Ni …. Setup: Cube-silicium • 6 DSSSD • 6 large-area silicon det. • detection • beam catcher or fast tape I. Matea et al. , CEN Bordeaux-Gradignan

Study of decay of 31 Ar at SPIRAL/LIRAT Proton spectrum • Production rate: 0. 5 – 1 31 Ar per second • strong contamination from 33 Ar I. Matea et al. , CEN Bordeaux-Gradignan

One- and two-proton emission from isomers: 94 Ag

One- and two-proton emission from isomers: 94 Ag Relative energy spectra for p-p 3 -body 0. 39(4)s Seq 1. 9 ke. V Si-Si- (92 Rh) I. Muhka, Nature 439 (2006) 298

LUMIERE: Laser Utilisation for Measurement and Ionization of Exotic Radioactive Elements • Collinear Laser spectroscopy: - spins - magnetic moments - quadrupole moments - change of charge radii N=50, N=64, N=82, etc. • -NMR spectroscopy: - nuclear gyromagnetic factor - quadrupole moment } for ground and isomeric states monopole migration of proton and neutron single particle levels around 78 Ni persistance of N=50 shell gap around 78 Ni persistance of N=82 shell gap beyond 132 Sn • Microwave double resonance in a Paul trap: - hyperfine anomaly and higher order momenta (octupole and hexadecapole deformation) Eu, Cs, Au, Rn, Fr, Ra, Am ….

Atomic hyperfine structure Interaction between an orbital e- (J) and the atomic nucleus (I, m. I, QS) ð results in a hyperfine splitting (HFS) of the e- energy levels n J EHFS F ð Hyperfine structure constants: with and ð Collinear laser spectroscopy: m. I/m. I ~ 10 -2, QS/QS ~ 10 -1 for heavy elements

Isotope shift measurements Frequency shift between atomic transitions in different isotopes of the same chemical element ð related to the mass and size differences J 2, F 2 J 1, F 1 n. A, A’ J 2, F 2 J 1, F 1 ð mean square charge radius variations with a precision ~ 10 -3 ð study of nuclei shape (deformation)

Isotope shift and nuclear moment measurements 178 Hf isomer at Orsay F. Le Blanc et al. 101 Zr at JYFL P. Campbell et al.

Isotope shift measurements v previous experiments: COMPLIS N~82 N~104 Ø onset of deformation at N=82 Ø shape transition (even-odd staggering) (slope ↔ rigidity) Ø dynamical effects (vibration) Ø shape coexistence F. Le Blanc et al. , IPN Orsay

Isotope shift measurements at DESIR v with I ~ 103 -104 pps: ð N~50: Ø neutron skin in N > 50 Ge isotopes (neutron star studies) Ø deformation in N ≤ 50 Ni isotopes (collectivity vs magicity) ð N~82: Ø shape evolution for Z ≤ 50 (Ag, Cd, In, Sn) ð N~64: Ø strongly oblate shapes predicted in Rb, Sr and Y for N > 64 ð Z~40: Ø shape transitions predicted in the Zr region (Mo, Tc, Ru) ð Rare earth elements: Ø large deformation and shape transitions predicted (Ba, Nd, Sm)

-NMR spectroscopy -asymmetry in the decay of polarized nuclei in a magnetic field ð Zeeman splitting related to g. I and QS M+I I B 0 M-I with and ð resonant destruction of the polarization (i. e. -asymmetry) by means of an additional RF magnetic field ð g. I/g. I ~ 10 -3, QS/QS ~ 10 -2 ð complementary technique to collinear laser spectroscopy ð suitable for light elements (low QS values)

The physics case for -NMR on polarized 60 ke. V beams à polarized 60 ke. V beams are obtained using resonant laser excitation. à with I ≥ 5. 103 pps, T½ from 1 ms to 10 s, beam purity > 50 %. à -NMR is a sensitive and precise method to measure g-factors and quadrupole moments of exotic nuclei (ground states, isomers) with lifetimes from 1 ms up to several seconds. à combination with hyperfine structure measurements yields a unique determination of the spin (e. g. PRL 94, 022501 (2005)). à Systematic precise measurements of g-factors reveal deviations from ‘normal’ behaviour and provide information on configuration mixing or onset of deformation (breaking of shell closures). à N~50: g factor of neutron-rich Ga and Cu isotopes to determine where the inversion of the pp 3/2 and pf 5/2 orbitals occurs. à N~82: g. s. configuration from g. I measurements.

The physics case for -NMR on polarized beams: nuclear structure towards and beyond 78 Ni Z=40 II L n RA sio I P s S d fi t a d uce e Se c nd u i od dr Ge P ith w Zn Z=28 Ni N=40 N=50 Lifetime OK for -NMR studies G. Neyens et al. , KU Leuven Kr Evolution of n orbits from Z=40 to Z=28: ground state spins and moments of 83 Ge, 81 Zn, 79 Ni and of 81 Ge, 79 Zn, 77 Ni àg-factors can reveal erosion of N=50 shell closure

Collinear laser spectroscopy and -NMR v previous experiments at COLLAPS: COLLAPS Ø from the position of hyperfine transitions: spin assignment and sign of g. I for the g. s. of 31 Mg asymmetry HFS 31 Mg 1+ n. RF (MHz) Ø from -NMR: precise measurement of |g. I| ð strongly deformed intruder Ip = 1/2+ g. s. of 31 Mg, G. Neyens et al, PRL 94, 022501 (2005) ð from QS measurements via -NMR: QS(11 Li) > QS(9 Li) p-n interaction + halo n orbitals, D. Borremans, Ph. D. Thesis, 2004, KU Leuven R. Neugart et al.

Estimated budget • Building: - DESIR hall: - Basement: - Crane: - 20 % overhead: 6000 k. Euros 3000 k. Euros 1000 k. Euros • HRS: 816 k. Euros - RFQ cooler: 150 k. Euros - 2 magnets + power supplies: 400 k. Euros - pumps, beam lines, diagonstics: 130 k. Euros - 20% overhead: 136 k. Euros • Beam handling: 1640 k. Euros - off-line source: 60 k. Euros - RFQ cooler/buncher and switch yards: 650 k. Euros - Preparation Penning trap: 460 k. Euros - in-trap decay detection system: 195 k. Euros - 20% overhead: 275 k. Euros • Lumière: 972 k. Euros - Laser room with infrastructure 150 k. Euros - Two lasers (dye + Ar) 180 k. Euros - Collinear laser spectroscopy: 170 k. Euros - ß-NMR set-up: 160 k. Euros - Paul trap set-up: 150 k. Euros - 20% overhead: 162 k. Euros • Decay spectroscopy: 2160 k. Euros - Four Germanium detectors: 1225 k. Euros - Fast timing set-up: 34 k. Euros - 4 p charged particle array: 168 k. Euros - Neutron detection array: 400 k. Euros - 20% overhead: 333 k. Euros • Fundamental interactions: 600 k. Euros - MOT trap: 350 k. Euros - in-flight decay setup: 150 k. Euros - 20% overhead: 100 k. Euros • Beam lines: 3600 k. Euros ------------------------------------------------------------------------TOTAL: 15788 k. Euros

The DESIR Collaboration Lynda Achouri, LPC Caen Alejandro Algora, IFIC Valencia Jean-Claude Angélique, LPC Caen Alain Astier, CSNSM Orsay Georges Audi, CSNSM Orsay Juha Aysto, University of Jyvaskyla Dimiter Balabanski, INRNE Sofia Emmanuel Balanzat, CIRIL Caen Gilles Ban, LPC Caen Bertram Blank, CENBG Bordeaux Klaus Blaum, University Mainz Maria Jose Garcia Borge, CSIC Madrid Dorel Bucurescu, NIPNE Bucarest Apostol Buta, NIPNE Bucarest Paul Campbell, University Manchester Grégory Canchel, CENBG Bordeaux Daniel Cano Ott, CIEMAT Madrid Joakim Cederkall, ISOLDE-CERN Fatima Dayras, CSNSM Orsay Giacomo de Angelis, INFN Legnaro Pierre Delahaye, ISOLDE-CERN Jean-Pierre Delaroche, CEA Bruyères Frank Delaunay, LPC Caen Isabelle Deloncle, CSNSM Orsay François de Oliveira Santos, GANIL Caen Philippe Dessagne, IPHC Strasbourg Gilbert Dûchene, IPHC Strasburg Cédric Dossat, DAPNIA Saclay Dominique Durand, LPC Caen Serge Franchoo, IPN Orsay Xavier Fléchard, LPC Caen Kieran Flanagan, University Leuven Carole Gaulard, CSNSM Orsay Bill Gelletly, University of Surrey Georgiev, CSNSM Orsay Omar Gianfrancesco, CSNSM Orsay Jérôme Giovinazzo, CENBG Bordeaux Stéphane Grévy, GANIL Caen Héloise Goutte, CEA Bruyères-le-Chatel Paul-Henri Heenen, University Brussels Frank Herfurth, GSI Darmstadt Jussi Huikari, CENBG Bordeaux Fadi Ibrahim, IPN Orsay Ari Jokinen, University Jyväskylä Andrea Jungclaus, University Madrid Klaus Jungmann, KVI Gronningen Swaminathan Kailas, BARC Mumbai Jürgen Kluge, GSI Darmstadt Magdalena Kowalska, University Mainz François Le Blanc, IPN Orsay Roy Lemmon, CCLRC Daresbury Marek Lewitowicz, GANIL Caen Etienne Liénard, LPC Caen David Lunney, CSNSM Orsay Miguel Marques, LPC Caen Ismael Martel, Universidad de Huelva Iolanda Matea, CENBG Bordeaux Enrique Minaya-Ramirez, CSNSM Orsay Iain Moore, University of Jyväskylä Oscar Naviliat-Cunic, LPC Caen Florin Negoita, NIPNE Bucarest Gerda Neyens, University Leuven C. J. G. Onderwater, KVI Groningen Nigel Orr, LPC Caen Dan Pantelica, NIPNE Bucarest Sophie Péru-Desenfants, CEA Bruyères Stephane Pietri, University of Surrey Natalie Pillet, CEA Bruyères-le-Chatel Zsolt Podolyak, University of Surrey Marie-Genevieve Porquet, CSNSM Orsay Wolfgang Quint, GSI Darmstadt Paul-Gerhard Reinhard, University of Erlangen Ernst Roeckl, GSI Darmstadt Daniel Rodriguez, Universidad de Huelva Brian Roeder, LPC Caen Bertra Rubio, University Valencia Lutz Schweikhard, University Greifswald Nathal Severijns, University Leuven Aradhana Shrivastava, BARC Mumbai Cosimo Signorini, INFN Padova Gary Simpson, LPSC Grenoble John Simpson, CCLRC Daresbury Olivier Sorlin, GANIL Caen Krunoslav Subotic, University Belgrade Olof Tengblad, CSIC Madrid Catherine Thibault, CSNSM Orsay Jean-Charles Thomas, GANIL Caen Dragan Toprek, University Belgrade Piet van Duppen, University Leuven David Verney, IPN Orsay Phil Walker, University Surrey Christine Weber, GSI Darmstadt L. Willmann, KVI Gronningen Hans Wilschut, KVI Gronningen Martin Winkler, GSI Darmstadt Nicolae Victor Zamfir, NIPNE Bucarest

Summary • solid physics case • very promising intensities for exotic nuclei (e. g. fusion-evaporation) • almost 100 co-authors the « DESIR » LOI • with its installations a unique facility • preliminary study of building at CENBG • study of cooler/buncher and HRS at CSNSM • installation of collinear laser spectroscopy at ALTO • to be built it has to be included in « reference solution » • synergies with FAIR: DESPEC, LASPEC, MATS, NCAP