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Alexander Herlert High-precision mass measurements for reliable nuclear-astrophysics calculations CERN, PH-IS NIC-IX, CERN, Geneva, June 29, 2006
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High-precision mass measurements for reliable nuclear-astrophysics calculations NIC-IX, CERN, Geneva, June 29, 2006 Atomic masses of radionuclides The ISOLTRAP experiment Principle of mass measurement Recent experimental results
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Nucleosynthesis and r-process fusion in stars s-process r-process Sn Pb Ni protons neutrons courtesy: K. Blaum, H. Schatz 50 82
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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
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Neutron Number N Proton Number Z In total: 1158 nuclides Atomic Mass Evaluation 2003 m/m < 10 -7 G. Audi, A.H. Wapstra, C. Thibault, Nucl. Phys. A 729
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Neutron Number N Proton Number Z In total: 181 nuclides Atomic Mass Evaluation 2003 m/m < 10 -8 G. Audi, A.H. Wapstra, C. Thibault, Nucl. Phys. A 729
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Neutron Number N Proton Number Z 133,134 Cs 85,87 Rb In total: 24 nuclides Atomic Mass Evaluation 2003 m/m < 10 -9 G. Audi, A.H. Wapstra, C. Thibault, Nucl. Phys. A 729
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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
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Production of radioactive nuclides at ISOLDE
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ISOLTRAP: Experimental setup buncher preparation trap precision trap 2m
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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
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B + q/m Principle of mass determination motional modes of ion stored in a Penning trap measurement of cyclotron frequency
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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
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TOF spectrummean TOF Principle of mass determination Example: 85 Rb (900ms excitation duration)
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TOF spectrummean TOF Principle of mass determination fit of theoretical line shape to the data Example: 85 Rb (900ms excitation duration)
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Principle of mass determination cyclotron frequency of "unknown" nuclide cyclotron frequency of well-known nuclide determination of mass ratio
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85 Rb 23 Na 39 K 133 Cs Stable alkali ions as mass references
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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
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Determination of the mass accuracy Combined carbon cluster cross-reference measurements m / u Relative mass accuracy limit: ( m/m) lim 8 10 -9 A. Kellerbauer et al., EPJ D 22, 53 (2003) m/m / 10 -8
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ISOLTRAP mass measurements in 2004-2005 71-81 Zn Nuclides measured in 2004/2005 Nuclides measured in 2004/2005 118,120,122-124 Cd 126 Xe, 136 Xe 127,128,131-134 Sn 84 Kr, 86-95 Kr 35-38 K, 43-46 K 17 Ne, 19 Ne 22 Mg 21-22 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
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The mass of 22 Mg 10 frequency ratios measured 16 relations included in 2 adjustment M. Mukherjee et al., Phys. Rev. Lett. 93, 150801 (2004). 22 Mg +
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Solving the mass discrepancy of 22 Mg 200 eV CPT J. Clark et al. M. Mukherjee et al., Phys. Rev. Lett. 93, 150801 (2004).
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protons neutrons Ion yields at ISOLDE
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protons neutrons yield (ions/ C) Ion yields at ISOLDE courtesy: M. Turrion SC and PSB yields
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ISOLDE target for Zn run courtesy: T. Stora et al. UC x target RILIS quartz transfer line protons
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Yields at ISOLTRAP estimate for target/ion source 0.5%
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Preliminary result for mass excess Zn Zn 81 Zn +
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protons neutrons yield (ions/ C) Ion yields at ISOLDE courtesy: M. Turrion SC and PSB yields
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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)
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In-trap decay results mass spetrometry of daughter nuclide 37 K + 37 Ar + Elements/isotopes which are in principle not produced are accessible!
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First application of in-trap decay mass spectrometry 61 Fe +
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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
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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 …
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