Energy splitting of the ground-state doublet in the nucleus 229Th.

  title={Energy splitting of the ground-state doublet in the nucleus 229Th.},
  author={B. R. Beck and John A. Becker and Peter Beiersdorfer and G V Brown and Kenton J. Moody and J. Wilhelmy and Frederick S. Porter and Caroline A. Kilbourne and Richard Lloyd Kelley},
  journal={Physical review letters},
  volume={98 14},
The energy splitting of the 229Th ground-state doublet is measured to be 7.6+/-0.5 eV, significantly greater than earlier measurements. Gamma rays produced following the alpha decay of 233U (105 muCi) were counted in the NASA/electron beam ion trap x-ray microcalorimeter spectrometer with an experimental energy resolution of 26 eV (FWHM). A difference technique was applied to the gamma-ray decay of the 71.82 keV level that populates both members of the doublet. A positive correction amounting… Expand
Prospects for measuring the 229Th isomer energy using a metallic magnetic microcalorimeter☆
  • G. Kazakov, V. Schauer, +7 authors T. Schumm
  • Medicine, Physics
  • Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment
  • 2014
It is studied, how state-of-the-art magnetic metallic microcalorimeters with an energy resolution down to a few eV can be used to measure the isomer energy of Thorium-229 and the dependence of the attainable precision of the energy measurement on the signal and background count rates and the instrumental resolution. Expand
The 229Th Isomer Line as a Reference for a High-Precision Frequency Standard
The use of the nuclide 229Th as a new nuclear-optical frequency standard is studied theoretically. The mechanism for two-photon optical pumping of the 7.6 eV isomer through the optical shell inExpand
Energy of the ^{229}Th Nuclear Clock Isomer Determined by Absolute γ-ray Energy Difference.
The low-lying isomeric state of ^{229}Th provides unique opportunities for high-resolution laser spectroscopy of the atomic nucleus and is determined by taking the absolute energy difference between the excitation energy required to populate the 29.2-keV state and the energy emitted in its decay to the isomersic excited state. Expand
Energy splitting between the first two quasi-particle states in 230Pa in comparison with the isotone 229Th
Excited states of the odd–odd isotope 230Pa have been identified by means of the one-neutron transfer reaction 231Pa(d→, t)230Pa at a beam energy of 22 MeV. The ground state of 230Pa is assigned toExpand
Toward an energy measurement of the internal conversion electron in the deexcitation of the 229 Th isomer
The first excited isomeric state of Th-229 has an exceptionally low energy of only a few eV and could form the gateway to high-precision laser spectroscopy of nuclei. The excitation energy of theExpand
Determination of the ground-state hyperfine structure in neutral 229Th
The ground-state hyperfine structure of neutral 229Th has been measured for the first time using high-resolution resonance ionization spectroscopy. The measurements were performed as a preparatoryExpand
Proposed experimental method to determine alpha sensitivity of splitting between ground and 7.6 eV isomeric states in 229Th.
Measurements of the differences of atomic transition frequencies between thorium atoms (or ions) with the nucleus in the ground state and in the first excited (isomeric) state are proposed to enable extraction of the change in nuclear charge radius and electric-quadrupole moment between the isomers, and hence the alpha dependence of the isomeric transition frequency with reasonable accuracy. Expand
X-ray pumping of the 229Th nuclear clock isomer
Active optical pumping is presented using narrow-band 29-kiloelectronvolt synchrotron radiation to resonantly excite the second excited state of 229Th, which then decays predominantly into the isomer, enabling accurate determination of the 229mTh isomer’s energy, half-life and excitation linewidth. Expand
Feasibility study of internal conversion electron spectroscopy of 229mTh
Abstract.With an expected energy of 7.8(5) eV, the isomeric first excited state in 229Th exhibits the lowest excitation energy of all known nuclei. Until today, a value for the excitation energy hasExpand
Experimental search for the low-energy nuclear transition in 229Th with undulator radiation
To search for the lowest energy nuclear isomeric transition in 229Th in solid samples, a novel adsorption technique which prepares 229Th atoms on a surface of CaF2 is developed. Adsorbed 229Th isExpand


Features of the low-energy level scheme of 229Th as observed in the α-decay of 233U
Abstract The γ-radiation emitted following the α-particle decay of 233 U has been studied using a variety of Ge(Li) spectrometers and a Si(Li) spectrometer system. Analysis of γ-singles and γγExpand
Nuclear laser spectroscopy of the 3.5 eV transition in Th-229
We propose high-resolution laser spectroscopy of the 3.5 eV nuclear transition in Th-229 in isolated atoms. Laser excitation of the nucleus can be detected efficiently in a double-resonance method byExpand
Observation of Electromagnetic Radiation from Deexcitation of the 229 Th Isomer
Experimental measurements of ultraviolet and visible emission from two samples containing {sup 233}U suggest the deexcitation of a reported 3.5eV isomeric level in {sup 229}Th. The unique phenomenonExpand
Nuclear transitions induced by synchrotron x-rays.
We discuss two rare but interesting processes by which synchrotron x-rays with energies up to about 100 keV may be used to induce nuclear transitions. In the NEET (Nuclear Excitation by ElectronicExpand
Determination of the first ionization potential of actinide elements by resonance ionization mass spectroscopy
Abstract Resonance ionization mass spectroscopy (RIMS) in the presence of an external static electric field has been used for the determination of photoionization thresholds. Extrapolation of theExpand
X-ray microcalorimeters for Astro-E2 and high-energy astrophysics
Abstract The Japan/US Suzaku (formerly Astro-E2) astrophysics mission has been successfully launched. Suzaku is a powerful new orbiting observatory for studying extremely energetic processes in theExpand
Nuclear quantum optics with x-ray laser pulses.
It is shown that present and upcoming high-frequency laser facilities, especially together with a moderate acceleration of the target nuclei to match photon and transition frequency, do allow for resonant laser-nucleus interaction. Expand
Lasers as a bridge between atomic and nuclear physics
Abstract This paper reviews the application of visible and ultraviolet laser radiation to several topics in low-energy nuclear physics. We consider laser-induced nuclear anti-Stokes transitions,Expand
Nuclear Data Sheets for A = 233☆☆☆
Abstract The available nuclear structure information for nine known nuclei (Ra,Ac,Th,Pa,U,Np,Pu,Am,Cm) with mass number A = 233 is presented. Various decay and reaction data are evaluated andExpand
The Astro-E2 X-ray spectrometer/EBIT microcalorimeter x-ray spectrometer
The x-ray spectrometer (XRS) instrument is a revolutionary nondispersive spectrometer that will form the basis for the Astro-E2 observatory to be launched in 2005. We have recently installed a flightExpand