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Title: Thorium-doped CsI: Implications for the thorium nuclear clock transition

Journal Article · · Physical Review A
ORCiD logo [1]; ORCiD logo [1]; ORCiD logo [1];  [1]; ORCiD logo [1]; ORCiD logo [1]
  1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
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For 229mTh isomer nucleus with an anomalously low nuclear excitation energy, E$$\star$$ (currently accepted value of 7.8 ± 0.5 eV), the bound internal conversion (BIC) decay process is caused by the excitation of a valence electron that is sensitive to the electronic structure of the atomic-sized neighborhood. For this, we analyze an experiment where an impacting Th ion is neutralized by a negatively charged ion-receiving cesium iodide (CsI) surface, to obtain the minimal nuclear excitation energy E$$\star\atop{min}$$ necessary for BIC promotion of a Th-impurity valence electron in a CsI matrix. We analyze two cases: CsI with Th deposited into the bulk and with Th deposited on the CsI surface. In the bulk we consider band gap effects while on the surface we consider the work function. The energy to pull the electron to the surface is 1.5 – 2.2 eV depending on the surface plane, while to promote to the conduction band in the bulk it is 1.5 eV. Therefore we conclude that the Th-surface interaction can significantly reduce the lower E$$\star$$ bound of 6.3 eV, as estimated from the direct observation of the Th-clock transition [von der Wense et al., Nature (London) 533, 47 (2016)]. We suggest coating the multichannel plate with differing materials leading to different Th-impurity gaps and work functions can further narrow the E$$\star$$ uncertainty interval.

Research Organization:
Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
Sponsoring Organization:
USDOE Laboratory Directed Research and Development (LDRD) Program
Grant/Contract Number:
AC52-06NA25396; 20140011DR
OSTI ID:
1463481
Alternate ID(s):
OSTI ID: 1455100
Report Number(s):
LA-UR-17-27341; PLRAAN; TRN: US1902303
Journal Information:
Physical Review A, Vol. 97, Issue 6; ISSN 2469-9926
Publisher:
American Physical Society (APS)Copyright Statement
Country of Publication:
United States
Language:
English
Citation Metrics:
Cited by: 2 works
Citation information provided by
Web of Science

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  • Fairchild, S. B.; Back, T. C.; Murray, P. T.
  • Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films, Vol. 29, Issue 3 https://doi.org/10.1116/1.3581058
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Figures / Tables (2)

FIG. 1(p. 4)figure FIG. 1
FIG. 2(p. 4)figure FIG. 2

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Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
Crystal Structure
Nuclear Clock
Band Gap
Crystal Structure
Nuclear Clock
Band Gap
Doped Crystals