A Penning trap as a precision mass balance – Q-Value determinations with ISOLTRAP and SMILETRAP Outline Workshop on NDBD, Durham, Klaus Blaum: University of Mainz and GSI Darmstadt Introduction and motivation Q-value measurements of radionuclides Conclusions and outlook Q-value measurements of “stable“ ions

Mass and Energy Energy–Mass equivalence  High-precision mass measurements convey information on nuclear and atomic binding energies Einstein 1905:

The Importance of Atomic Masses General Physics fundam. constants test of CPT  m/m  1· Atomic Physics binding energy, QED in HCI  m/m  1·10 -9 Weak Interactions symmetry tests, CVC hypothsis  m/m < 3·10 -8 Astro- physics nuclear synthesis, r-, rp-process  m/m < 1·10 -7 Nuclear Physics mass formula, models, halo  m/m  1·10 -7 Physics & Chemistry basic information required  m/m  1·10 -6 Weighing atomic masses

A Brief History of Mass Spectrometry Bulk properties, liquid drop, shells Sub-shells, pairing, halos Symmetries, fundamental tests of concepts PTMSReaction Q RF Spectrometers Mass Spectrographs

Principle of Penning Traps Cyclotron frequency: B q/mq/m PENNING trap Strong homogeneous magnetic field Weak electric 3D quadrupole field ring electrode end cap Frans Michel Penning Hans G. Dehmelt

Ion Motion in a Penning Trap Motion of an ion is the superposition of three characteristic harmonic motions: –axial motion (frequency f z ) –magnetron motion (frequency f – ) –modified cyclotron motion (frequency f + ) The frequencies of the radial motions obey the relation Typical frequencies q = e, m = 100 u, B = 6 T  f - ≈ 1 kHz f + ≈ 1 MHz

Excitation of Radial Ion Motions Dipolar azimuthal excitation Either of the ion's radial motions can be excited by use of an electric dipole field in resonance with the motion (RF excitation)  amplitude of motion increases without bounds Quadrupolar azimuthal excitation If the two radial motions are excited at their sum frequency, they are coupled  they are continuously converted into each other Conversion of radial motions Magnetron excitation:   Cyclotron excitation:  +

TOF Resonance Mass Spectrometry Scan of excitation frequency Quadrupolar radial excitation near f c  coupling of radial motions, conv. Time-of-flight (TOF) measurement Ejection along the magnetic field lines  radial energy converted to axial energy Dipolar radial excitation at f -  increase of r m Time-of-flight resonance technique Resolving power:

Mean time of flight /  s Excitation frequency f rf / Hz T 1/2 =  TOF Cyclotron Resonance Curve (Stable Nuclide) TOF as a function of the excitation frequency Centroid: Determine atomic mass from frequency ratio with a well-known “reference mass”.

Triple-Trap Mass Spectrometer ISOLTRAP F. Herfurth, et al., NIM A 469, 264 (2001) K. Blaum et al., NIM B 204, 478 (2003) cluster ion source preparation Penning trap precision Penning trap stable alkali ion reference source ion beam cooler and buncher removal of contaminant ions (R = 10 5 ) determination of cyclotron frequency (R = 10 7 ) B = 4.7 T B = 5.9 T Nd:YAG 532 nm 1.2 m 10 cm K. Blaum et al., EPJ A 15, 245 (2002) 10 cm

ISOLTRAP Setup at ISOLDE/CERN 1 m

Problem of Reference Masses 85 Rb 23 Na 39 K 133 Cs

Carbon Clusters as Reference Masses C2C2 C3C3 C4C4 C4C4 C5C5 C6C6 C7C7 C8C8 C9C9 C 10 C 11 C 12 C 11 C 12 C 13 C 14 C 15 C 16 C 17 C 18 C 19 C 18 C 19 C 20 C 21 C 22 C1C1 K. Blaum et al., EPJ A 15, 245 (2002)

Benefits of Carbon Clusters as Reference Masses  References throughout the chart of the nuclides  Reference mass at most 6 u from the measured mass  Absolute mass measurements can be performed: 12 C is microscopic mass standard: u = 1/12 m( 12 C)  elimination of the uncertainty of the reference mass by definition  Cross-reference measurements allow determination of various uncertainties of setup and procedure and determination of the present mass accuracy limit  References throughout the chart of the nuclides  Reference mass at most 6 u from the measured mass  Absolute mass measurements can be performed: 12 C is microscopic mass standard: u = 1/12 m( 12 C)  elimination of the uncertainty of the reference mass by definition  Cross-reference measurements allow determination of various uncertainties of setup and procedure and determination of the present mass accuracy limit Residual mass uncertainty: (  m/m) res  8·10 -9 K. Blaum et al., EPJ A 15, 245 (2002) A. Kellerbauer et al., EPJ D 22, 53 (2003)

Superallowed  Decay and the Standard Model Conserved-vector-current hypothesis: –Vector part of weak interaction not influenced by strong interaction –Intensity of β decays (ft value) only a function of the vector coupling constant and the matrix element: Corrections: –to the statistical rate function f δ C – isospin symmetry breaking correction (Coulomb force, strong force) –to the nuclear matrix element  M V  : δ R – radiative correction (bremsstrahlung etc.) K – Product of fund. constants G V – Vector coupling constant  M V  - Nuclear matrix element

Experimental Access to Ft Value Q– Decay energy  mass m T 1/2 – Half-life b– Branching ratio P EC – Electron capture fraction δ R – Radiative correction δ C – Isospin symmetry breaking correction Unitarity of the CKM matrix –Mean Ft value of all decay pairs contributes to V ud via G V –Can check unitarity via sum of squares of elements of the first row  m/m < 3·10 -8 Weak Interaction symmetry tests, CVC hypothesis 

Results – FT Value ISOLTRAP mass measurements 22 Mg → 22 Na :  Q=0.28 keV, 34 Ar → 34 Cl :  Q=0.41 keV, 74 Rb → 74 Kr :  Q=4.5 keV 22 Mg 74 Rb F. Herfurth et al., Eur. Phys. J. A 15, 17 (2002) A. Kellerbauer et al., Phys. Rev. Lett.93, (2004) M. Mukherjee et al., Phys. Rev. Lett. 93, (2004) [I.S. Towner & J.C. Hardy, submitted to Phys. Rev. C (2005)] 34 Ar 62 Ga JYFLTRAP T z = -1 T z = 0

Status – CKM Matrix Check unitarity via elements of the first row: V us and V ub from particle physics data (K and B meson decays) From nuclear β decay (world average 2005): V ud obtained from avg. Ft and G A from muon decay From neutron decay: V ud obtained from neutron β decay asymmetry A and lifetime  (RPP world average 2002) [H. Abele et al., PRL 88 (2002) ] [I.S. Towner & J.C. Hardy, submitted to Phys. Rev. C (2005)]  = (14)

Contribution to the unitarity: Solution to the Non-Unitarity Problem 99.95% 0.05% %V ub V ud V us V ud (nuclear  -decay) = (4) V us (kaon-decay) = (26) V ub (B meson decay) = (5) Present status: PDG2004 Hardy2005 New measurement of V us from K e3 + decay  V us  = (30) New measurement of V us from K L decay  V us  = (23) BUT –in disagreement with previous K e3 + decay data –in disagreement with K e3 0 decay data  = (16) [A. Sher et al., PRL 91 (2003) ] [RPP 2002:  V us  = (26)] [T. Alexopoulos et al., PRL 93 (2004) ] [A. Lai et al., arXiv:hep-ex/ ]

SMILETRAP: High-Precision Mass Measurements Principle: Using highly-charged stable ions Cyclotron frequency: S tockholm M ainz I on LE vitation TRAP

SMILETRAP: High-Precision Mass Measurements –Precision Trap After injection aperture : 150 ions Captured : 50 ions After energy selection : 1-4 ions –50 mV / 2 V –PreTrap After magnet: 10 6 ions 1/250 beam captured : 4000 –pretrap length/beam length –2 V deep trap / 7 V energy spread I. Bergström et al., Eur. Phys. J. D 22, 41 (2003).

Determination of the 3 T  3 He Q-Value Q-value of Tritium beta decay Q=18 588(1.7) eV SMILETRAP KATRIN LOI: If a 1ppm precision (  20 meV) in the 3 He-T mass difference  M ( 3 He,T) and the absolute calibration of KATRIN could be achieved the sensitivity on m could be improved further by using an external  M ( 3 He,T) value in the analysis.

-less double  -decay Question: Is there a -less double  -decay? Reaction: 76 Ge 1Kg

76 Ge- 76 Se for constraints on neutrino-less double beta decay 17-times improvement in both masses 7-times improvement in the Q-value (50) keV Reaction: AME95 Manitoba71 Manitoba85 SMILETRAP G. Douysset et. al. PRL 86, 2001 Energy for 2e- by Q-value for 76 Se 76 Ge

Some Neutrino-Less Double Beta Decay Candidates 2  + Decay Q-value Precision 40 Ca – 40 Ar 193.6(0.2)5.7E Zn – 64 Ni1095.7(0.9)1.5E Se – 74 Ge1209.7(2.3)3.4E Kr – 78 Se2856.4(2.0)2.8E Cd – 106 Ag2770.0(7.2)7.3E-08 2  - 48 Ca – 48 Ti4273.7(4.1)9.1E Ge – 76 Se (50)7.1E Se – 82 Kr2995.7(2.6)3.4E Zr – 96 Mo3349.5(3.6)4.0E Cd – 116 Sn2809.1(4.2)3.9E-08 Almost all Q-values can be improved by a factor of 10 (  Q < 200 eV), but we need your input concerning the importance.

Conclusions and Outlook The development of a “carbon cluster-comb” was a breakthrough in mass spectrometry of radionuclides. ISOLTRAP and JYFLTRAP can perform high-precision mass measurements (< ) on very short-lived nuclides (< 100 ms) that are produced with very low yields (< 100 ions/s); SMILETRAP (< ) on stable highly-charged ions. Such high-precision mass measurements can provide valuable input to nuclear structure and fundamental studies. New developments (e.g. Ramsey) will allow even higher precision and can thus help to discover exciting new physics. We need your wishes for Q-value measurements on 0 2 . Ion traps are an ideal tool to perform atomic and nuclear physics precision experiments!

Not to Forget … Thanks to my colleagues: J. Äystö, G. Audi, G. Bollen, D. Beck, I. Bergström, P. Delahaye, T. Fritioff, S. George, C. Guénaut, A. Herlert, F. Herfurth, A. Jokinen, A. Kellerbauer, H.-J. Kluge, D. Lunney, Sz. Nargy, S. Schwarz, R. Schuch, L. Schweikhard, C. Yazidjian Thanks for the funding and support: GSI, BMBF, CERN, ISOLDE, HGF EU networks EUROTRAPS, EXOTRAPS, and NIPNET Thanks a lot for your attention.