Alexander Herlert High-precision mass measurements on exotic nuclides: recent results from the ISOLTRAP experiment CERN, PH-IS EP Seminar, CERN, May 15, 2006

High-precision mass measurements on exotic nuclides: recent results from the ISOLTRAP experiment EP Seminar, CERN, May 15, 2006 Atomic masses of radionuclides The ISOLTRAP experiment Principle of mass measurement Recent experimental results New techniques and methods

Radionuclides - What accuracy is needed? Nuclear Physics nuclear binding energies, Q-values shell closures, pairing, deformation, halos, isomers test of nuclear models and formulae  m/m  1·10 -7 Astrophysics nuclear synthesis r- and rp-process  m/m  1·10 -7 Weak Interaction symmetry tests CVC hypothesis  m/m  1·10 -8 ( p, )  ( p, )  ( p, )   +  +  + Hot cycle Cold cycle Common 11 Li

Neutron Number N Proton Number Z In total: 3180 nuclides Measured masses: 2228 Atomic Mass Evaluation 2003 all nuclides G. Audi, A.H. Wapstra, C. Thibault, Nucl. Phys. A 729

Neutron Number N Proton Number Z In total: 1158 nuclides Atomic Mass Evaluation 2003  m/m < G. Audi, A.H. Wapstra, C. Thibault, Nucl. Phys. A 729

Neutron Number N Proton Number Z In total: 181 nuclides Atomic Mass Evaluation 2003  m/m < G. Audi, A.H. Wapstra, C. Thibault, Nucl. Phys. A 729

Neutron Number N Proton Number Z 133,134 Cs 85,87 Rb In total: 24 nuclides Atomic Mass Evaluation 2003  m/m < G. Audi, A.H. Wapstra, C. Thibault, Nucl. Phys. A 729

See: Lunney, Pearson & Thibault, Rev. Mod. Phys. 75 (2003) Mass measurement programs for radionuclides worldwide

 operating facilities  facilities under construction or test  planned facilities  TRIUMF Argonne   MSU  Jyväskylä GSI  Stockholm   LBL SHIPTRAP HITRAP ISOLTRAP REXTRAP ATHENA ATRAP WITCH JYFL TRAP SMILETRAP CPT LEBIT RETRAP TITAN MAFF TRAP  Munich CERN  RIKEN TRAP Penning traps at accelerators

Production of radioactive nuclides at ISOLDE

ISOLTRAP: Experimental setup buncher preparation trap precision trap 2m

B = 4.7 T B = 5.9 T 2 m G. Bollen, et al., NIM A 368, 675 (1996) F. Herfurth, et al., NIM A 469, 264 (2001) determination of cyclotron frequency (R = 10 7 ) removal of contaminant ions (R = 10 5 ) Bunching of the continuous beam ISOLTRAP: Experimental setup

B + q/m Principle of mass determination measurement of cyclotron frequency Superposition of strong homogeneous magnetic field weak electrostatic quadrupole field

B + q/m motional modes of ion stored in a Penning trap Principle of mass determination measurement of cyclotron frequency

Scan QP-excitation freq. rf about c Quadrupole excitation rf Time-of-flight (TOF) radial  axial energy Magnetron excitation Principle of mass determination Conversion of magnetron into cyclotron motion B z Trap MCP Detector passing B-field gradient after ejection

TOF spectrummean TOF Principle of mass determination Example: 85 Rb (900ms excitation duration)

TOF spectrummean TOF Principle of mass determination fit of theoretical line shape to the data Example: 85 Rb (900ms excitation duration)

Principle of mass determination cyclotron frequency of "unknown" nuclide cyclotron frequency of well-known nuclide determination of mass ratio

85 Rb 23 Na 39 K 133 Cs Stable alkali ions as mass references

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) Carbon clusters as mass references

Determination of the mass accuracy Combined carbon cluster cross-reference measurements m / u Relative mass accuracy limit: (  m/m) lim  8  A. Kellerbauer et al., EPJ D 22, 53 (2003)  m/m / 10 -8

ISOLTRAP mass measurements in Zn Nuclides measured in 2004/2005 Nuclides measured in 2004/ ,120, Cd 126 Xe, 136 Xe 127,128, Sn 84 Kr, Kr K, K 17 Ne, 19 Ne 22 Mg Na Highlights NuclideHalf-lifeUncertainty 17 Ne 22 Mg 35 K 109 ms 3.86 s 178 ms 530 eV 270 eV 530 eV 81 Zn 290 ms3.45 keV

Nucleosynthesis and r-process fusion in stars s-process r-process Sn Pb Ni protons neutrons courtesy: K. Blaum 50 82

ISOLDE target for Zn run courtesy: T. Stora et al. UC x target RILIS quartz transfer line protons

Yields at ISOLTRAP estimate for target/ion source 0.5%

Result for 81 Zn 81 Zn +

Preliminary result for mass excess Zn preliminary Zn m = A·m u + ME

2n separation energy AME2003 Zn

2n separation energy ISOLTRAP AME2003 Zn

131 Sn isomer AME2003 G. Audi et al.

Removal of contaminants for Sn measurements Sn Sn 34 S 127,128, Sn isobaric contaminants (Cs) Sn 34 S

Preliminary result for mass excess Sn preliminary M. Dworschak et al. 131 Sn ???

The mass of 17 Ne lightest nuclide measured at ISOLTRAP two-proton halo candidate: A. Ozawa et al., Phys. Lett B 334, 18 (1994) M.V. Zhukov et al., PRC 52, 3505 (1995) R. Kanungo et al., Phys. Lett. B 571, 21 (2003)

AME2003  m < 600 eV The mass of 17 Ne 17 Ne 17 Ne + T 1/2 = 109 ms Yield ISOLDE = 1000/s About 450 ions/h at ISOLTRAP m = A·m u + ME

The two-proton halo candidate 17 Ne How to probe if 17 Ne is a proton halo? 17 Ne Isotope-shift measurements: (COLLAPS experiment, Neugart et al.) Mass uncertainty of  m /m  1·10 -7 (~ 2 keV) required!  nuclear charge radii Via the nuclear charge radii!

Collaps upper limit Collaps lower limit Finite range Droplet Preliminary result without new mass values PhD thesis W. Geithner

Fermi  -decays between analog states of spin J  =0 + and isospin T=1 conserved vector current hypothesis: ft = const M V Fermi-matrix element G V coupling constant for semileptonic weak interaction J.C. Hardy and I.S. Towner, Phys. Rev. C 71, (2005) Conserved vector current (CVC) hypothesis radiative corrections  R and  R isospin not exact symmetry: isospin-symmetry-breaking correction  C

Superallowed  -decay nuclides - 9 best known cases experimental data needed: Q BR, t 1/2 f = f (Z,Q) t = f (BR,t 1/2 ) 10 C 14 O 26m Al 34 Cl 38m K 42 Sc 46 V 50 Mn 54 Co T z = -1 T z = 0 statistical rate function partial half-life J.C. Hardy and I.S. Towner, Phys. Rev. C 71, (2005)

I.S. Towner and J.C. Hardy, Phys. Rev. C 66, (2002) Superallowed  -decay nuclides - 9 best known cases (8) s

Cabibbo-Kobayashi-Maskawa (CKM) matrix Unitarity 95% 5% 0.001%V ub V ud V us Contribution to the unitarity: Unitarity of CKM matrix weak interaction coupling constant G F from muon decay

discrepancy by more than 2  Further experimental data as well as refined calculations of correction terms needed I.S. Towner and J.C. Hardy, Phys. Rev. C 66, (2002) Unitarity of CKM matrix Result:

The mass of 22 Mg 10 frequency ratios measured 16 relations included in  2 adjustment M. Mukherjee et al., Phys. Rev. Lett. 93, (2004). 22 Mg +

Solving the mass discrepancy of 22 Mg 200 eV CPT J. Clark et al. M. Mukherjee et al., Phys. Rev. Lett. 93, (2004).

3072.7(8) s J.C. Hardy and I.S. Towner, Phys. Rev. C 71, (2005) Updated values F. Herfurth et al., EPJA 15, 17 (2002) A. Kellerbauer et al., PRL 93, (2004) M. Mukherjee et al., PRL 93, (2004)

V ud (nuclear  -decay) = (4) V us (kaon-decay) = (26) V ub (B meson decay) = (47) Present status: i.e. CKM not unitary at the 98% confidence level (non-)unitarity of CKM-matrix J.C. Hardy and I.S. Towner, Phys. Rev. C 71, (2005) Updated values for CKM unitarity test V us (K + -decay) = (30)  (Brookhaven E865) V us (K + -decay) = (22) (Fermilab E832) new result for V us :

Outlook for CKM unitarity test T z = -1 T z = 0 extend investigation to other nuclides increase precision on nine best ft-values

J.C. Hardy and I.S. Towner, Phys. Rev. C (2005) Outlook for CKM unitarity test

New experimental methods and technical development How to improve ISOLTRAP ?

New ion sources new ion source Pierre Delahaye

New ion sources carbon cluster ion source Nd:YAG Manas Mukherjee

Preparation of ions - removal of isobaric contaminants cooling resonance of 41 K + removal of 39 K + by dipolar excitation

New detection schemes excitation with Ramsey technique Sebastian George

Drift tube Window (open access) Channeltron detector Spare MCP detector Feed- through Ions from the precision trap New detector setup

Detection efficiency MCP Detection efficiency Channeltron Better statistical uncertainty  30%  90% Get access to shorter- lived nuclides (  50mm) (  12mm) MCP Comparison of efficiency MCP/Channeltron

new detector CEM MCP Number of Ions per Pulse Time / ms Comparison of efficiency

Stabilization of magnetic field temperature and pressure stabilization

Stabilization of magnetic field temperature frequency c Maxime Brodeur

Stabilization of magnetic field including linear drift of magnetic field

New temperature-stabilization system Heater Fan temperature sensor Slobodan Djekic and Melanie Marie-Jeanne

New temperature regulation +/- 15mK

+/- 0.1 mbar New pressure regulation He recovery line

+/- 5mK New temperature regulation - first results

Isomerism in 68 Cu: as produced by ISOLDE isolation of the 1 + ground state isolation of the 6 - isomeric state Resolving power of excitation: R ≈ 10 7  Population inversion of nuclear states  Preparation of an isomerically pure beam J. Van Roosbroeck et al., Phys. Rev. Lett. 92, (2004) K. Blaum et al., Europhys. Lett. 67, 586 (2004) Isomer Separation: 68 Cu

Isomerically pure ion beam Tape station Beta-counter Trap assisted spectroscopy

Decay in the buffer-gas-filled preparation trap ZXZX A Z-1 Y A e+e+ + produced at ISOLDE not produced at ISOLDE 20 cm z (mm) 4 He e+e+ e+e+ ZXZX A ZXZX A e+e+ ZXZX A Z-1 Y A A A ZXZX A e+e+ ZXZX A e+e+  Make more radioactive species available  Nearly simultaneous  c measurement of mother and daughter nuclei  Test candidate: 37 K  37 Ar  Make more radioactive species available  Nearly simultaneous  c measurement of mother and daughter nuclei  Test candidate: 37 K  37 Ar A novel idea: In-trap decay mass spectrometry Herlert et al., New J. Phys. 7, 44 (2005)

In-trap decay results mass spetrometry of daughter nuclide 37 K + 37 Ar + Elements/isotopes which are in principle not produced are accessible!

Result for doubly charged (stable) xenon ions Herlert et al., IJMS 251, 131 (2006)

mass determination with a time-of-flight cyclotron resonance detection technique limited by: nuclide production rate above 100 s -1 half-life (so far) over 65ms systematic uncertainty limit: Summary so far mass measurements on more than 300 radionuclides at ISOLTRAP for tests of nuclear structure, mass models, a contributions to a CKM unitarity test,... new techniques and development: in-trap decay method, new ion sources and detector, magnetic field stabilization, new excitation schemes,... (  m/m) lim  8  10 -9

Thanks to my co-workers: G. Audi, S. Baruah, D. Beck, K. Blaum, G. Bollen, M. Breitenfeldt, P. Delahaye, M. Dworschak, S. George, C. Guénaut, U. Hager, F. Herfurth, A. Kellerbauer, H.-J. Kluge, D. Lunney, M. Marie-Jeanne, M. Mukherjee, S. Schwarz, R. Savreux, L. Schweikhard, C. Weber, C. Yazidjian,..., and the ISOLTRAP and ISOLDE collaboration Thanks for the funding and support: BMBF, GSI, CERN, ISOLDE, EU networks EUROTRAPS, EXOTRAPS, and NIPNET Thanks a lot for your attention! Not to forget …