Condensed Matter Physics Using Nuclear Resonant Scattering

Seto, Makoto

doi:10.7566/jpsj.82.021016

Cited by 16 publications

(6 citation statements)

References 135 publications

(163 reference statements)

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“…On-resonance (with the nuclear excitation energy), this process also takes place, producing a "prompt" background. However, additionally, the nucleus is excited to the 2 nd excited state with a certain cross section, referred to as nuclear resonant scattering (NRS) [80]. This nuclear excitation decays again with a characteristic timescale, 82 ps in the case of 229 Th (29.19 keV level).…”

Section: X-ray Pumping Nuclear Resonant Scatteringmentioning

confidence: 99%

Nuclear clocks for testing fundamental physics

Peik

Schumm

Safronova

et al. 2021

Quantum Sci. Technol.

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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 innovative ideas and studies that expand the understanding of atomic and nuclear structure of heavy elements and of the interaction of nuclei with bound electrons and coherent light. Using the nuclear resonance frequency, determined by the strong and electromagnetic interactions inside the nucleus, it is possible to build a highly precise nuclear clock that will be fundamentally different from all other atomic clocks based on resonant frequencies of the electron shell. The nuclear clock will open opportunities for highly sensitive tests of fundamental principles of physics, particularly in searches for violations of Einstein’s equivalence principle and for new particles and interactions beyond the standard model. It has been proposed to use the nuclear clock to search for variations of the electromagnetic and strong coupling constants and for dark matter searches. The 229Th nuclear optical clock still represents a major challenge in view of the tremendous gap of nearly 17 orders of magnitude between the present uncertainty in the nuclear transition frequency (about 0.2 eV, corresponding to ∼48 THz) and the natural linewidth (in the mHz range). Significant experimental progress has been achieved in recent years, which will be briefly reviewed. Moreover, a research strategy will be outlined to consolidate our present knowledge about essential 229mTh properties, to determine the nuclear transition frequency with laser spectroscopic precision, realize different types of nuclear clocks and apply them in precision frequency comparisons with optical atomic clocks to test fundamental physics. Two avenues will be discussed: laser-cooled trapped 229Th ions that allow experiments with complete control on the nucleus–electron interaction and minimal systematic frequency shifts, and Th-doped solids enabling experiments at high particle number and in different electronic environments.

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Section: X-ray Pumping Nuclear Resonant Scatteringmentioning

confidence: 99%

Nuclear clocks for testing fundamental physics

Peik

Schumm

Safronova

et al. 2021

Quantum Sci. Technol.

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“…Conceptually, this scheme is identical to nuclear resonant scattering (NRS) 16 . The present experiment, however, requires several specific developments to account for the short half-life (∼ 100 ps, shortest half-life ever measured in NRS) and the extremely small signal-tobackground ratio (∼ 10 −6 ) due to the narrow excitation linewidth of the 29-keV level.…”

Section: Measurement Principlementioning

confidence: 99%

X-ray pumping of the 229Th nuclear clock isomer

Masuda

Yoshimi

Fujieda

et al. 2019

Nature

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Thorium-229 is a unique case in nuclear physics: it presents a metastable first excited state 229m Th, just a few electronvolts above the nuclear ground state. This so-called isomer is accessible by VUV lasers, which allows transferring the amazing precision of atomic laser spectroscopy to nuclear physics. Being able to manipulate the 229 Th nuclear states at will opens up a multitude of prospects, from studies of the fundamental interactions in physics to applications as a compact and robust nuclear clock. However, direct optical excitation of the isomer or its radiative decay back to the ground state has not yet been observed, and a series of key nuclear structure parameters such as the exact energies and half-lives of the low-lying nuclear levels of 229 Th are yet unknown. Here we present the first active optical pumping into 229m Th. Our scheme employs narrow-band 29 keV synchrotron radiation to resonantly excite the second excited state, which then predominantly decays into the isomer. We determine the resonance energy with 0.07 eV accuracy, measure a half-life of 82.2 ps, an excitation linewidth of 1.70 neV, and extract the branching ratio of the second excited state into the ground and isomeric state respectively. These measurements allow us to re-evaluate gamma spectroscopy data that have been collected over 40 years.

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“…The monochromatic beam is used in various research fields that require an accurate photon energy. For example, in nuclear resonant scattering (NRS) experiments [1], narrow resonance peaks of NRS sometimes need to be found. Knowing the accurate photon energy helps in finding the resonance without wide energy scanning, which is especially useful for searching weak resonance peaks.…”

Section: Introductionmentioning

confidence: 99%

Absolute X-ray energy measurement using a high-accuracy angle encoder

Masuda,

Watanabe,

Beeks

et al. 2020

Preprint

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This paper presents an absolute X-ray photon energy measurement method that uses a Bond diffractometer. The proposed system enables the prompt and rapid in-situ measurement of photon energies in a wide energy range. The diffractometer uses a reference silicon single crystal plate and a highly accurate angle encoder called SelfA. We evaluate the performance of the system by repeatedly measuring the energy of the first excited state of the potassium-40 nuclide. The excitation energy is determined as 29 829.39(6) eV. It is one order of magnitude more precise than the previous measurement. The estimated uncertainty of the photon energy measurement was 0.7 ppm as a standard deviation and the maximum observed deviation was 2 ppm.

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Condensed Matter Physics Using Nuclear Resonant Scattering

Cited by 16 publications

References 135 publications

Nuclear clocks for testing fundamental physics

Nuclear clocks for testing fundamental physics

X-ray pumping of the 229Th nuclear clock isomer

Absolute X-ray energy measurement using a high-accuracy angle encoder

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