The 229-thorium isomer: doorway to the road from the atomic clock to the nuclear clock

  title={The 229-thorium isomer: doorway to the road from the atomic clock to the nuclear clock},
  author={Peter G. Thirolf and Benedict Seiferle and Lars C. von der Wense},
  journal={Journal of Physics B: Atomic, Molecular and Optical Physics},
The elusive ‘thorium isomer’, i.e. the isomeric first excited state of 229Th, has puzzled the nuclear and fundamental physics communities for more than 40 years. With an exceptionally low excitation energy and a long lifetime it represents the only known candidate so far for an ultra-precise nuclear frequency standard (‘nuclear clock’), potentially able to outperform even today’s best timekeepers based on atomic shell transitions, and promising a variety of intriguing applications. This… 

The thorium-229 low-energy isomer and the nuclear clock

The 229Th nucleus has an isomeric state at an energy of about 8 eV above the ground state, several orders of magnitude lower than typical nuclear excitation energies. This has inspired the

Nuclear clocks for testing fundamental physics

The low-energy, long-lived isomer in 229Th, first studied in the 1970s as an exotic feature in nuclear physics, continues to inspire a multidisciplinary community of physicists. It has stimulated

Extending Our Knowledge about the 229Th Nuclear Isomer

The first nuclear excited state in 229Th possesses the lowest excitation energy of all currently known nuclear levels. The energy difference between the ground- and first-excited (isomeric) state

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The proposal for the development of a nuclear optical clock has triggered a multitude of experimental and theoretical studies. In particular the prediction of an unprecedented systematic frequency

Measurement of the ^{229}Th Isomer Energy with a Magnetic Microcalorimeter.

A measurement of the low-energy (0-60 keV) γ-ray spectrum produced in the α decay of ^{233}U using a dedicated cryogenic magnetic microcalorimeter and four complementary evaluation schemes is presented.

Atomic Physics Studies at the Gamma Factory at CERN

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Time-varying fine structure constant from naturally ultralight dark matter

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Direct detection of the 229Th nuclear clock transition

The direct detection of this nuclear state of 229mTh is reported, which is further confirmation of the existence of the isomer and lays the foundation for precise studies of its decay parameters.

Laser spectroscopic characterization of the nuclear-clock isomer 229mTh

The laser spectroscopic investigation of the hyperfine structure of the doubly charged 229mTh ion and the determination of the fundamental nuclear properties of the isomer, namely, its magnetic dipole and electric quadrupole moments, as well as its nuclear charge radius are presented.

Towards a measurement of the nuclear clock transition in 229Th

We investigate a potential candidate for a future optical clock: the nucleus of the isotope 229Th. Over the past 40 years of research, various experiments have found evidence for the existence of an

Experiments Towards Optical Nuclear Spectroscopy With Thorium-229

  • Physics
  • 2010
The discovery of the low-lying isomeric nuclear state of Th at 7.6 ± 0.5 eV above the ground state opened a new field of research as a bridge between nuclear and atomic physics. Since indirect

Excitation of the 229mTh nuclear isomer via resonance conversion in ionized atoms

Pressing problems concerning the optical pumping of the 7.6-eV 229mTh nuclear isomer, which is a candidate for a new nuclear optical reference point for frequencies, are examined. Physics behind the

Observation of the Deexcitation of the Th 229 m Nuclear Isomer

The $^{229}\mathrm{Th}$ nucleus possesses the lowest-energy nuclear isomeric state. Two widely accepted indirect measurements of the transition energy place it within reach of existing laser

Constraining the evolution of the fundamental constants with a solid-state optical frequency reference based on the 229Th nucleus.

It is argued that the 229Th optical nuclear transition may be driven inside a host crystal with a high transition Q to allow for the construction of a solid-state optical frequency reference that surpasses the short-term stability of current optical clocks, as well as improved limits on the variability of fundamental constants.

The concept of laser-based conversion electron Mössbauer spectroscopy for a precise energy determination of 229mTh

Abstract229Th is the only nucleus currently under investigation for the development of a nuclear optical clock (NOC) of ultra-high accuracy. The insufficient knowledge of the first nuclear excitation

Prospects for measuring the 229Th isomer energy using a metallic magnetic microcalorimeter☆

  • G. KazakovV. Schauer T. Schumm
  • Physics
    Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment
  • 2014