The DESIR facility at SPIRAL2DESIR: Dsintgration, excitation et stockage dions radioactifs (Decay, excitation and storage of radioactive ions)

Result of a SPIRAL2 workshop in July 2005 on ISOL beams at SPIRAL2:

- Decay spectroscopy:Maria Jos Garci Borge (Madrid) - LASER spectroscopy:Franois Le Blanc (IPN Orsay)Gerda Neyens (KU Leuven)Paul Campbell (Manchester) - Atom and ion traps:Dave Lunney (CSNSM)Oscar Naviliat-Cuncic (LPC CaenFrank Herfurth (GSI)

Spokes-person: Bertram Blank

GANIL liaison: Jean-Charles Thomas

Bertram Blank, SAC SPIRAL2, 19-20 October 2006

Why another ISOL facility? 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 78Ni, 100Sn, 132Sn with high intensities fusion-evaporation to access high-spin states

Low energy RIB1.A new experimental area of about 1500m2 located at the ground floor, dedicated to the experiments with low-energy beams from SPIRAL2 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.Conclusions of the SPIRAL2 Workshop (july 2005):

DESIR physics program Decay spectroscopy - decay properties and nuclear structure studies- particle-particle correlations, cluster emission, GT strength - exotic shapes, halo nuclei

Laser spectroscopy - static properties of nuclei in their ground and isomeric states- deformation

Fundamental interactions- CVC hypothesis, CKM matrix unitarity via 0+ 0+ transitions- exotic interactions (scalar and tensor currents)- CP (or T) violation with e.g. Radium

Solid state physics and other applications

SPIRAL 2 LAYOUTGANIL facilityLIRAT

UndergroundJ.C. Thomas, GANIL

DESIR: Ground-floorxtrapneutronsgeneralpurposespecbuncherIon sourceslaserPaultrapMOTBESTIOLLUMIERE

Beam handling: methodsMagnetic separation (HRS)PENNING TRAPA. Jokinen, JYFL

RFQ-cooler:3 p mm mrad, 0.5 eV, 10 ms, 60 %Beam handling: RFQ cooler and buncherD. Lunney et al., CSNSM

Beam handling: ImplementationF. Varenne, GANIL

Decay studies with halo nuclei Clustering studies in light nuclei Super-allowed b 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 correlationSummary of decay spectroscopy experiments:The BESTIOL facility(BEta decay STudies at the SPIRAL2 IsOL facility)

Decay properties of exotic nuclei Very Selective probe Global properties-delayed particle emission1916Rutherford & Wood [Philos. Mag. 31 (1916) 379]1963 Barton & Bell identified 25Si as p emitterE, Level densitySpin, Isospin -decay properties

within the SMx : Fermi fraction; r : GT/F mixing ratio beyond the SMa contains quadratic S and T contributions b-n angular correlationrequires to measure the recoil ion + b particleSearch for exotic interactionsO. Naviliat-Cuncic et al., LPC Caene+nenucleusq

6He+ production at SPIRALLIRAT low energy beam linecooling in H2 gas / bunchingtrapping/measuringcandidate: (pure GT transition) deduce bn angular correlation from measurement of b-recoil(recoil with very low energies < 1 keV)Search for exotic interactions:Production and preparation of 6He O. Naviliat-Cuncic et al., LPC Caen

TOF of ions extracted from trap first time difference for b-decay (V-A theory)RF ON/OFFSearch for exotic interactions: Setup and first resultsO. Naviliat-Cuncic et al., LPC Caen

Vud0+0+ = 0.9738(4) (1) 0.9736(3) (1,2,3) VusK = 0.2200(23) (PDG) 0.2254(21) (4) VubB = 0.00367(47) (PDG)

= 3073.5 (12) s (1) 3074.4 (12) s (1,2)(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) E865, KTeV, NA48, KLOE(PDG) Particle Data Group, S. Eidelman et al., PLB 592 (2004) 1(~ 2 shift) 0.9987(11)CVC, CKM, exotic currents: 0+ 0+ b decaysMeasurements: - Q value - T1/2 - branching ratios

1. Vud matrix element ( test of unitarity)

2. test of CVC (constancy of Ft0+ 0+ values)

3. right-handed currents:

-0.0005 < < 0.0015 (90% C.L.)

4. scalar currents:Ad 3: Left Right Symm.-models W1 = WL cos - WR sinW2 = WL sin + WR cos = m12 / m22 Ad 4: scalar currents0.0110+ 0+ b decays: Physics outputN. Severijns et al.

0+ 0+ b decays: Future studies further improve results for classical isotopes

determine Ft-values for new isotopes of interest:

Tz = -1 isotopes: 18Ne, 22Mg, 26Si, 30S, 34Ar, 38Ca, 42Ti

Tz = 0 isotopes: 62Ga, 66As, 70Br, 74Rb, 78Y, 82Nb, 86Tc, 90Rh, 94Ag, 98In

stronger limits for new physics test and improve reliability of isospin corrections extend CVC test to higher mass region

needs: - relatively pure beams ( 103 at/s) of classical and new 0+ 0+ isotopes - precision spectroscopy techniques (for t1/2 and BR)- Penning traps (mainly for QEC/mass)

Study of GT strength via b-delayed proton decay: 21Mg21MgJ.C. Thomas

Mirror symmetry studiesAverage asymmetry d : 11 (1) % in the 1p shell (A

Search for p-p correlation in b2p decayTwo possible decay schemes: sequential no angular or energy correlation 2He type decay angular and energy correlation pairing correlations, nucleon-nucleon interaction, final-state interactions.Possible candidates:22Al, 23Si, 26P, 27S, 31Ar, 35Ca, 43Cr, 50Ni .Setup: Cube-silicium 6 DSSSD 6 large-area silicon det. g detection beam catcher or fast tapeI. Matea et al., CEN Bordeaux-Gradignan

Study of decay of 31Ar at SPIRAL/LIRAT Production rate: 0.5 1 31Ar per second strong contamination from 33ArI. Matea et al., CEN Bordeaux-GradignanProton spectrum

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

3-body I. Muhka, Nature 439 (2006) 2981.9 keVSi-Si- (92Rh)0.39(4)sRelative energy spectra for p-p One- and two-proton emission from isomers: 94Ag

Collinear Laser spectroscopy: - spins - magnetic moments - quadrupole moments - change of charge radii

N=50, N=64, N=82, etc.

b-NMR spectroscopy: - nuclear gyromagnetic factor - quadrupole moment

monopole migration of proton and neutron single particle levels around 78Ni persistance of N=50 shell gap around 78Ni persistance of N=82 shell gap beyond 132Sn

Microwave double resonance in a Paul trap: - hyperfine anomaly and higher order momenta (octupole and hexadecapole deformation)

Eu, Cs, Au, Rn, Fr, Ra, Am . LUMIERE:Laser Utilisation for Measurement and Ionization of Exotic Radioactive Elements

Atomic hyperfine structureInteraction between an orbital e- (J) and the atomic nucleus (I,mI,QS) results in a hyperfine splitting (HFS) of the e- energy levels JnFDEHFSwith Hyperfine structure constants: and Collinear laser spectroscopy: DmI/mI ~ 10-2, DQS/QS ~ 10-1 for heavy elements

Isotope shift measurementsFrequency shift between atomic transitions in different isotopes of the same chemical element related to the mass and size differences J1, F1J2, F2J1, F1J2, F2dnA,A mean square charge radius variations with a precision ~ 10-3 study of nuclei shape (deformation)

Isotope shift and nuclear moment measurements101Zr at JYFLP. Campbell et al.178Hf isomer at OrsayF. Le Blanc et al.

previous experiments:Isotope shift measurements N~82 N~104 F. Le Blanc et al., IPN Orsay

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

b-NMR spectroscopyb-asymmetry in the decay of polarized nuclei in a magnetic field Zeeman splitting related to gI and QSIM+IM-I resonant destruction of the polarization (i.e. b-asymmetry) by means of an additional RF magnetic fieldwith and DgI/gI ~ 10-3, DQS/QS ~ 10-2 complementary technique to collinear laser spectroscopy suitable for light elements (low QS values)

The physics case for b-NMR on polarized 60 keV beams polarized 60 keV beams are obtained using resonant laser excitation.

with I 5.103 pps, T from 1 ms to 10 s, beam purity > 50 %.

b-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.

combination with hyperfine structure measurements yields a unique determination of the spin(e.g. PRL 94, 022501 (2005)).

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).

N~50: g factor of neutron-rich Ga and Cu isotopes to determine where the inversion of the pp3/2 and pf5/2 orbitals occurs.

N~82: g.s. configuration from gI measurements.

The physics case for b-NMR on polarized beams:NiZnnuclear structure towards and beyond 78NiEvolution of n orbits from Z=40 to Z=28:

ground state spins and momentsof 83Ge, 81Zn, 79Ni and of 81Ge, 79Zn, 77Ni

g-factors can reveal erosion of N=50 shell closureProduced at SPIRALIIwith d-induced fissionLifetime OK for b-NMR studiesGeSeKrG. Neyens et al., KU Leuven

Collinear laser spectroscopy and b-NMR previous experiments at COLLAPS: from the position of hyperfine transitions: spin assignment and sign of gI for the g.s. of 31MgHFS 31Mg1+ from b-NMR: precise measurement of |gI|nRF (MHz)b asymmetry strongly deformed intruder Ip = 1/2+ g.s. of 31Mg, G. Neyens et al, PRL 94, 022501 (2005) from QS measurements via b-NMR: QS(11Li) > QS(9Li) p-n interaction + halo n orbitals, D. Borremans, Ph.D. Thesis, 2004, KU Leuven R. Neugart et al.

Estimated budget Building:6000 kEuros - DESIR hall:3000 kEuros - Basement:1000 kEuros - Crane:1000 kEuros - 20 % overhead:1000 kEuros HRS: 816 kEuros - RFQ cooler: 150 kEuros - 2 magnets + power supplies: 400 kEuros - pumps, beam lines, diagonstics: 130 kEuros - 20% overhead: 136 kEuros Beam handling:1640 kEuros - off-line source: 60 kEuros - RFQ cooler/buncher and switch yards: 650 kEuros - Preparation Penning trap: 460 kEuros - in-trap decay detection system: 195 kEuros - 20% overhead: 275 kEuros

Lumire: 972 kEuros - Laser room with infrastructure 150 kEuros - Two lasers (dye + Ar) 180 kEuros - Collinear laser spectroscopy: 170 kEuros - -NMR set-up: 160 kEuros - Paul trap set-up: 150 kEuros - 20% overhead: 162 kEuros

Decay spectroscopy:2160 kEuros - Four Germanium detectors:1225 kEuros - Fast timing set-up: 34 kEuros - 4p charged particle array: 168 kEuros - Neutron detection array: 400 kEuros - 20% overhead: 333 kEuros

Fundamental interactions: 600 kEuros - MOT trap: 350 kEuros - in-flight decay setup: 150 kEuros - 20% overhead: 100 kEuros

Beam lines:3600 kEuros------------------------------------------------------------------------------------------------------------------------------------------------TOTAL: 15788 kEuros

The DESIR Collaboration

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