MPI für Physik, München 2015 Nuclear Ground State Properties and their Importance for Nuclear Structure, Nuclear Astrophysics and Fundamental Studies. Motivation for precision nuclear data Atomic physics techniques in nuclear physics Applications of nuclear ground state data Klaus Blaum June 23 rd , 2015 Klaus.blaum@mpi-hd.mpg.de
Characteristics of a (radioactive) nucleus its weight its size its life-time/decay its shape its mood (state) its e.m. properties In recent years unique tools have been developed to determine experimentally and to describe theoretically these characteristics.
Nuclear ground state properties What do we learn? nuclear binding energy Masses basic test of nuclear models nuclear structure: shell closures, magic numbers, pairing, onset of deformation, drip lines, halos Charge Radii nuclear structure: nuclear charge distribution, deformation Spins, microscopic nuclear structure: wave functions, coupling of nucleons, configuration mixing, shell Moments structure macroscopic nuclear structure: deformation
Atomic and nuclear masses Masses determine the atomic and nuclear binding energies reflecting all forces in the atom/nucleus. = N · + Z · + Z · – binding energy M Atom = N • m neutron + Z • m proton + Z • m electron - ( B atom + B nucleus )/ c 2 δ m / m = 10 -6 – 10 -8 δ m / m < 10 -10
Storage of ions in a Penning trap B U Ion q/m Charge q Mass m ω = The free cyclotron frequency is inverse / qB m c proportional to the mass of the ions! An invariance theorem ω c = ω + + ω - ω c 2 = ω + 2 + ω - 2 + ω z 2 saves the day: L.S. Brown, G. Gabrielse, Rev. Mod. Phys. 58, 233 (1986). K. Blaum, J. Dilling, W. Nörtershäuser, Phys. Scr. T152, 014017 (2017).
Cyclotron frequency detection techniques R ∝ 1/ T obs Destructive time-of-flight detection Space/ Number of detected ions Phase resolving detection R ∝ 1/ T obs ∙ ∆φ /2 π Mass accuracy of δ m / m = 10 -10 demonstrated! S. Eliseev et al ., Phys. Rev. Lett. 110, 082501 (2013)
A Penning-trap setup In collaboration with W. Nörtershäuser (TUD) and Ch. Düllmann (UMz).
Laser spectroscopy and nuclear structure Isotope 1 Isotope Shift := Frequency difference in an electronic transition between two isotopes Isotope 2 Hyperfine Structure 2 M r Isotope Shift
Basics of (collinear) laser spectroscopy electrostatic charge exchange cell (Na) deflection ion beam electrostatic lenses excitation & observation reg. E kin <60 keV + for retardation laser beam fixed frequency + + o ∆ o 25 25 Mg Mg HFS of HFS of photons 6.5 A(S 1/2 ) = 596.5(5) MHz photo multiplier 300 350 400 250 250 fine Doppler tuning voltage (V) fine
Isotope production at ISOLDE ~ 10 6 -10 7 11 Be + /s T 1/2 = 13.6 s
Masses Nuclear structure studies ESR, ISOLTRAP, SHIPTRAP, TITAN
Ca masses pin down nuclear forces Multi-reflection time-of-flight and Penning-trap mass spectrometry 51,52 Ca 53,54 Ca B R. Wolf et al ., Int. J. Mass Spec. 349, 123 (2013) T. Dickel et al ., Nucl. Instrum. Meth. B 317, 779 (2013) N = 28 magic Production rates of ~10 ions/s number Mass measurements via S 2n establish new magic number N = 32 magic number at N = 32 Correct prediction from N =31,32 3N-forces (A. Schwenk et al ., TUD) TITAN Z =20 Ca F. Wienholtz et al ., Nature 498, 346 (2013) ISOLTRAP (CERN), TITAN (TRIUMF)
Nuclear halos 11 Be n 10 Be characteristic properties of nuclear halos large matter radius weakly bound increased charge radius 11 Li 207 Pb 9 Li +2n ? 11 = 9 r c r c 375 keV 0 keV 3/2 - probing halo 11 Li neutron – nucleus interaction
Be spectroscopy – laser system
Disappearance of the N = 8 shell closure 11 Be 12 Be T 1/2 [s] 13.6 0.02 Yield [s -1 ] 7 × 10 6 1 × 10 3 Phys. Rev. Lett. 102, 062503 (2009) Phys. Rev. Lett. 108, 142501 (2012) and Phys. Rev. Lett. (in print)
The simple picture 9 Be 9 Be 7 Be 7 Be 8 Be 8 Be 11 Be 11 Be 10 Be 10 Be 11 Be 11 Be 11 Be 7.7 fm 7.7 fm
Masses and radii Nuclear astrophysics studies CPT, CSRe, ESR, ISOLTRAP, JYFLTRAP, LEBIT, SHIPTRAP, TITAN
Mass spectrometry for nucleosynthesis Nuclear masses (binding energies) determine the paths of the processes. Nuclear astrophysics studies: Masses, Half-lifes, Reaction Rates
Nuclear astrophysics: Neutron star Composition of the outer crust of a neutron star ( T 1/2 ~ 200ms) δ m / m ~ 10 -8 (< 1 keV) R. Wolf et al ., Phys. Rev. Lett., 110, 041101 (2013)
Nuclear astrophysics: r-process Compare calculated abundance to observation Mismatch comes from: - n-star-merger conditions! - Nuclear physics input not correct. Need nuclear physics experiments & theory for predictions! rapid neutron capture β-decay Z seed A. Arcones et al.,2012 N H. Schatz et al. (γ,n) photo- equilibrium favours MNRAS.426.1940 disintegration “ waiting point ”
Towards highest precision Nuclear masses for fundamental studies FSU, ISOLTRAP, JYFLTRAP, SHIPTRAP, THe-TRAP, TRIGATRAP
Non-destructive ion detection ion signal mass/frequency spectrum Amplitude „FT-ICR“ very small signal ~fA F ourier- T ransform- I on C yclotron R esonance
THe-TRAP for KATRIN A high-precision Q ( 3 T- 3 He)-value measurement − → + + ν 3 3 H He e Q lit =18 589.8 (1.2) eV 1 2 Q lit =18 592.01(7) eV [E. Myers, PRL (2015)] We aim for: δ Q ( 3 T 3 He) = 20 meV ∆ T < 0.2 K/d at 24°C δ m / m = 7·10 -12 ∆ B/B < 100 ppt / h ∆ x ≤ 0.1 µ m First 12 C 4+ / 16 O 6+ mass ratio measurement at δ m / m = 1.4∙10 -11 performed.
The ECHO ( 163 Ho) project Metallic Magnetic Calorimetry Q -value of EC in 163 Ho Q -value with δ Q <1 eV Status in 2014
Summary Exciting results in high-precision mass spectrometry / laser spectroscopy with stored and cooled exotic ions! Thank you for the invitation and your attention! Email: klaus.blaum@mpi-hd.mpg.de WWW: www.mpi-hd.mpg.de/blaum/ Max Planck Society IMPRS-PTFS Adv. Grant MEFUCO Helmholtz Alliance
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