Low-energy experiments at ISOLDE – atomic, nuclear, and fundamental

physics

Magdalena KowalskaISOLDE Physics Coordinator

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Outline

Low-energy part of ISOLDEInterest: nuclear, atomic, and fundamental physicsPenning-trap-based studies: ISOLTRAP and WITCHLaser spectroscopy: COLLAPS, CRIS, RILISDecay studiesSummary and outlook

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Low-energy ISOLDETarget stations

HRS & GPS

Mass-sep.HRS

ISCOOLRILIS

REX-TRAP

PS-Booster 1.4 GeV protons

3×1013 ppp

ISOLTRAP

CRIS

COLLAPS

NICOLE

WITCH

Travelling setups

30-60 keV ion beameV energy spread and small emittancePossibility to bunch beam (ms bunches)Many fixed and travelling setups

Collection points (applications)

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Low energy: interest

Nuclear Physics

Nuclear Decay Spectroscopy Structure of Nuclei

Exotic Decay Modes

Atomic PhysicsLaser Spectroscopy and

Direct Mass Measurements

Radii, Moments, Nuclear Binding Energies

Nuclear Astrophysics

Dedicated Nuclear Decay Studies

Element Synthesis, Solar Processes

f(N,Z)

Fundamental PhysicsDirect Mass Measurements,

Dedicated Decay Studies – WICKM unitarity tests,

search for -b n correlations, right-handed currents

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Laser spectroscopy

ISCOOLRILIS

CRIS

COLLAPS

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Laser spectroscopy and nuclear physics - Spin (orbital+intrinsic angular momentum), parity (Ip)

- Nuclear g-factor and magnetic dipole moment (gI and mI)- Electric quadrupole moment (Q)

- Charge radius ( )r 2r 2

Give information on:- Configuration of neutrons and protons in the nucleus

- Size and form of the nucleus

r 2r 2

volume

deformation

pairing

0d5/2

1s1/2

0d3/2

Ip=2+

m = +0.54

0d5/2

1s1/2

0d3/2

Ip=2+

m = +1.83

gI and mI Q

Q<0oblate

Q=0spherical

Q>0prolate

Ip

0d5/2

1s1/2

0d3/2

1/2+

3/2+

0d5/2

1s1/2

0d3/2

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Laser and b-NMR Spectroscopy

Detection method depends on the case => optimised for best S/N ratioObservables: Hyperfine structure, isotope shifts, Nuclear Magnetic Resonance

Information: ground-state spin (+parity assignment), charge radius, moments=> Probing single-particle and collective properties

Laser beam,Laser on fixed frequency

Ion beam

Electrostaticdeflection

Retardation zone

Neutralisation region

Excitation / Observation region

Collinear laser spectroscopycrystals

RF-coilplastic

scintilators

magnet poles

Beam from ISOLDE

Beam from ISOLDE

Beta-NMRCOLLAPS setup

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Charge radii of Ne isotopes

Intrinsic density distributions of dominant proton FMD configurations

Laser spectroscopy

Geithner et al, PRL 101, 252502 (‘08)Marinova et al, PRC (‘12)

Open projects:IS484: Ground-state properties of K-isotopes from laser and β-NMR spectroscopyIS497: Laser Spectroscopy of Cadmium Isotopes: Probing the Nuclear Structure Between the Neutron 50 and 82 Shell ClosuresIS517: Determination of the Magnetic Moment of 140-PrIS519: Shell structure and level migrations in zinc studied using collinear laser spectroscopyIS529: Spins, Moments and Charge Radii Beyond 48Ca

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CRISCollinear Resonant Ionisation SpectroscopyHigh sensitivity, lower resolution -> perfect for heavy ions

First physics experiment in 2011: HFS and decay of 207Fr

Open projects:IS471: Collinear resonant ionization laser spectroscopy of rare francium isotopesIS531: Collinear resonant ionization spectroscopy for neutron rich copper isotopes

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RILISResonant Ionisation Laser Ion Source; one way to ionise produced atomsNd: YAG pumping dyo or Ti:Sa lasers, with possibility of doubling to quadruplingAtomic physics: Used to determine ionisation schemes and ionising potential of chemical elements with no stable isotopes (e.g. polonium, astatine)Nuclear physics: laser spectroscopy -> electromagnetic ground state properties

3 Ti:Sa lasers

Harmonic generation unit for Ti:Sa system

Nd:YAG pump laser for the Ti:Sa lasers

Dye lasers with 2nd harmonic generation and UV pumping option

Nd:YAG laser for dye pumping or non resonant ionizationNarrow band dye laser

for high resolution spectroscopy or isomer selectivity

Dye laser 3rd harmonic generator

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RILIS – nuclear structure

T.E. Cocolios et al., PRL 106 (2011) 052503M. Seliverstof et al., EPJ A41(2009) 315H. De Witte et al., PRL 98 (2007) 112502

Changes in charge radii of heavy nuclei

Open projects:IS456: Study of polonium isotopes gs properties by simultaneous atomic- and nuclear-spectroscopyIS466: Identification and systematical studies of the electron-capture delayed fission (ECDF) in the lead region - Part I: ECDF of 178,180Tl and 200,202Fr isotopesIS511: Shape coexistence in the lightest Tl isotopes studied by laser spectroscopyIS534: Beta-delayed fission, laser spectroscopy and shape-coexistence studies with radioactive At beams

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RILIS – atomic structureAstatine beams:Determination of ionising potentialIdentification of new atomic transitionsComparison with atomic theory

Recent projects:PoloniumAstatine

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Penning-trap studies

REX-TRAP

ISOLTRAP

WITCH

Ion manipulation with rf in Penning trapsPossibility of purifying the ion ensembles

magnetron (-) cyclotron (+)

axial (z)

ISOLTRAP

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Bm

qc

2

1

Cyclotron frequency in magnetic field => atomic mass

determination of cyclotron frequency

(R = 107)

removal of contaminant ions

(R = 105)

Bunching of thecontinuous beam

Beta- and gamma decay studies

10 ms, 1-10%10-100

ms, >50%

50 ms- 1 s,100%

50 ms -10 s,100%

ISOLTRAP

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ISOLTRAPHigh-precision mass of 82Zn (Oct 2011):

after several attempts at ISOLTRAP and other Penning traps

Nuclear structure: N=50 shell closure

Astrophysics: r-process path

Astrophysics: neutron star structure

Combined ISOLDE technical know-how: neutron-converter, quartz transfer line, laser ionisation

IS490: Masses of noble gasesIS498: High-Precision Mass Measurements in the Rare-Earth Region to Investigate the Proton-Neutron InteractionIS518: First Study of the Stability of the N=126 Shell ClosureIS535: Penning-trap mass spectrometry of neutron-rich copper isotopes for probing the Z = 28 and N = 50 shell closures

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WITCHWeak Interation Trap for Charged particles -> fundamental studiesGoal: determine bn correlation for 35Ar with (a/a)stat 0.5 %

-> energy spectrum of recoiling ions with a retardation spectrometerUse a Penning trap to create a small, cold ion bunch

M. Beck et al., Eur. Phys. J. A47 (2011) 45M. Tandecki et al., NIM A629 (2011) 396S. Van Gorp et al., NIM A638 (2011) 192

recoil ion energy (eV)

# r

ecoi

l io

ns

1000

3000

2000

0 200 400 600

35Ar recoil spectrum(preliminary; 4 h ; 5 x 105 at/C)

two differ. normalizations(agree within error bars)

June 2011 data:

First high-statistics run in Nov 2011(data analysis ongoing)

Open experiment:IS433: Search for new physics in beta-neutrino correlations using trapped ions and a retardation spectrometer

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Decay studies

(ISOLTRAP)

(CRIS)

Travelling setups

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Beta-delayed fissionTravelling alpha-decay station looking at beta-delayed fission

180Hg (Z=80, N=100, N/Z=1.25) does not fission in two semi-magic 90Zr(Z=40,N=50)

IS466: Identification and systematical studies of the electron-capture delayed fission (ECDF) in the lead regionIS534: Beta-delayed fission, laser spectroscopy and shape-coexistence studies with radioactive At beams

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Exotic decays of light nuclidesLooking at both emitted particles and gamma rays

Open projects:IS445: Experiments with the newly available Carbon beams at ISOLDE - Resonance scattering and decay studiesIS476: Studies of beta-delayed two-proton emission : The cases of 31Ar and 35CaIS507: Study of the beta-decay of 20MgIS525: Study of multi-neutron emission in the beta-decay of 11Li IS541: Search for beta-delayed protons from 11Be

Double Sided Silicon Strip Detectors

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Exotic decays of heavy nucleiProposal by U. Datta Pramanik (Saha): Experimental investigation of decay properties of neutron deficient 116-118Ba isotopes and test of 112-115Ba beam counts (IS545)Kolkata, Valencia, Geneva, Aarhus, Goteborg, Grenoble, New Delhi, Santiniketan, Cologne, EdinburghUse Si detector for particle detection and

HpGe or LaBr3 detectors for gamma detection Aim: look for exotic decay modes

(alpha and possible cluster emission)

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Other decay studies

Fast-timing studies

Change of electron capture nuclear decay rate under compression

Classical -b g decay studies (e.g. Mn, Hf)

Travelling setups

Gamma spectroscopy with BaF2 crystals (very fast response, <ps lifetime studies)

Open experiments: IS441: Ultra fast timing measurements at 78Ni and 132SnIS474: Fast-timing studies of nuclei below 68Ni populated in b-decay of Mn isotopes

IS467: Beta-decay studies of neutron rich 61-70Mn isotopes with the new LISOL beta-decay setupIS537: Properties of neutron-rich hafnium high-spin isomers

Scintillators and Ge detectors

Precision measurement of the half-life of 107In large and small lattice environments

Kolkata, Raniganj, Geneva, Cologne

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Trap- or laser-assisted decay studies

Decay stations behind ISOLTRAP and CRISIsobar and even isomer purification in a Penning trap or by laser ionisationStudies of radionuclides suffering from contamination

Open projects at ISOLTRAP:IS463: Mass measurements and decay studies on isobarically pure neutron-rich Hg and Tl isotopesIS513: Study of the odd-A, high-spin isomers in neutron-deficient trans-lead nuclei with ISOLTRAP

Open projects at CRIS:IS463: Mass measurements and decay studies on isobarically pure neutron-rich Hg and Tl isotopesIS513: Study of the odd-A, high-spin isomers in neutron-deficient trans-lead nuclei with ISOLTRAP

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Other fixed low-energy setups

Presently:Total Absorption SpectrometerLow Temperature Orientation beta-NMR setup

In the future:Fixed versatile decay station: collaboration being setup, contributions welcomeMOT (Magneto-Optical Trap) for weak-interaction studies

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How to perform such studies at ISOLDE

Join existing collaborationPut a new letter of intent or proposal and involve group(s) familiar with ISOLDE

Check existing experiments at http://isolde.web.cern.ch/ISOLDE/default2.php?index=index/expindex.htm&main=experiments/explist.php Planning: next experimental campaign in 2014 (mostly for low-energy physics); proposals due in 2013

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Summary and outlook

ISOLDE provides a wealth of radionuclides at low energiesBeams are monoenergetic, have small emittance, and can be bunchedPhysics interest: atomic, nuclar, fundamental physicsStudies performed by several fixed setups and many travelling experimentsTechniques: decay studies, laser spectroscopy, Penning-trap studiesResults: everywhere in the nuclear chartHow to perform such studies: join or create a collaboration and put a proposal with large chances to run in 2014

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Thank you for your attention