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Creators/Authors contains: "Elwell, R."

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  1. ; ; ; ; ; (, Physical Review Letters)
  2. ; ; ; ; ; ; ; (, Physical Review Research)
    The population dynamics of the Th 229 isomeric state is studied in a solid-state host under laser illumination. A photoquenching process is observed, where off-resonant vacuum-ultraviolet (VUV) radiation leads to relaxation of the isomeric state. The cross-section for this photoquenching process is measured, and a model for the decay process, where photoexcitation of electronic states within the material band gap opens an internal conversion decay channel, is presented and appears to reproduce the measured cross-section. By engineering defects into Th 229 -doped solid-state hosts, this previously unrecognized photoquenching process may be used to reduce the clock transition readout time and thereby increase the stability of the nuclear clock. Published by the American Physical Society2025 
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    Free, publicly-accessible full text available June 1, 2026
  3. ; ; ; ; ; ; ; (, Applied Physics Letters)
    The recent laser excitation of the 229Th isomeric transition in a solid-state host opens the door for a portable solid-state nuclear optical clock. However, at present, the vacuum-ultraviolet laser systems required for clock operation are not conducive to a fieldable form factor. Here, we propose a possible solution to this problem by using 229Th-doped nonlinear optical crystals, which would allow clock operation without a vacuum-ultraviolet laser system and without the need of maintaining the crystal under vacuum. We investigate electronic properties and thorium doping in BaMgF4 and BaZnF4 with density functional theory, predicting BaMgF4 to be the superior material, and evaluate the performance of a Th:BaMgF4 clock. 
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    Free, publicly-accessible full text available March 1, 2026
  4. ; ; ; ; ; ; ; ; ; ; et al (, Nature)
    Free, publicly-accessible full text available December 19, 2025
  5. ; ; ; ; ; ; ; ; (, Physical Review Letters)
  6. ; ; ; ; ; ; ; ; ; ; et al (, Physical Review Research)
    A comparative vacuum ultraviolet spectroscopy study conducted at ISOLDE-CERN of the radiative decay of the Th 229 m nuclear clock isomer embedded in different host materials is reported. The ratio of the number of radiative decay photons and the number of Th 229 m embedded are determined for single crystalline CaF 2 ,   MgF 2 ,   LiSrAlF 6 , AlN, and amorphous SiO 2 . For the latter two materials, no radiative decay signal was observed and an upper limit of the ratio is reported. The radiative decay wavelength was determined in LiSrAlF 6 and CaF 2 , reducing its uncertainty by a factor of 2.5 relative to our previous measurement. This value is in agreement with the recently reported improved values from laser excitation. Published by the American Physical Society2025 
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    Free, publicly-accessible full text available January 1, 2026