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Title: Excitation of the {sup 229m}Th nuclear isomer via resonance conversion in ionized atoms

Pressing problems concerning the optical pumping of the 7.6-eV {sup 229m}Th nuclear isomer, which is a candidate for a new nuclear optical reference point for frequencies, are examined. Physics behind the mechanism of the two-photon optical pumping of the isomer is considered. It is shown that, irrespective of the pumping scheme, a dominant contribution comes, in accord with what was proven earlier for the 3.5-eV isomer, from the resonance 8s–7s transition. Details of an optimum experimental scheme are discussed. It is shown that, after isomer excitation, the atom involved remains with a high probability in an excited state at an energy of about 0.5 eV rather than in the ground state, the required energy of the two photons being equal to the energy of the nuclear level plus the energy of the lowest 7s state of the atom. The estimated pumping time is about 1.5 s in the case where the field strength of each laser is 1 V/cm.
Authors:
 [1] ;  [2]
  1. D.I. Mendeleev Institute for Metrology (VNIIM) (Russian Federation)
  2. National Research Center Kurchatov Institute, Petersburg Nuclear Physics Institute (Russian Federation)
Publication Date:
OSTI Identifier:
22472165
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Atomic Nuclei; Journal Volume: 78; Journal Issue: 6; Other Information: Copyright (c) 2015 Pleiades Publishing, Ltd.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
74 ATOMIC AND MOLECULAR PHYSICS; 73 NUCLEAR PHYSICS AND RADIATION PHYSICS; ATOMS; CONVERSION; EV RANGE; EXCITATION; EXCITED STATES; GROUND STATES; IONIZATION; ISOMERIC NUCLEI; LASER RADIATION; OPTICAL PUMPING; PHOTONS; PROBABILITY; RESONANCE