Dissertation / PhD Thesis

PUBDB-2026-02250

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Optical Emission Spectroscopy of Highly Charged Ions for a Cf$^{15+/17+}$ Ion Clock

Kozhiparambil Sajith, L. P. (Corresponding author)DESY* ; Worm, S. (Thesis advisor)DESY* ; Krutzik, M. (Thesis advisor) ; Quint, W. (Reviewer)Extern*

2026

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Please use a persistent id in citations: doi:10.18452/38153  doi:10.3204/PUBDB-2026-02250

Abstract: Searches for physics beyond the Standard Model can be pursued through high-precision measurements of atomic systems that are sensitive to variations in fundamental constants. In this thesis, highly charged ions (HCI) are investigated as promising candidates for optical clocks to probe new physics. Particular emphasis is placed on highly charged californium (Cf) ions, which exhibit transitions in the optical region arising from level crossings that are highly sensitive to variations in the fine-structure constant. To facilitate the investigation of these transitions, the Heidelberg electron beam ion trap (HD-EBIT) is described, followed by the development of a compact clock setup that integrates a miniature EBIT, ion extraction beam line, and Paul trap as a step toward precision spectroscopy and clock operation with HCIs. The design and implementation of a dedicated injection system for rare and radioactive elements in the HD-EBIT (such as Cf) is described, focusing on the technical challenges associated with the construction of the apparatus. As a proof-of-principle study for Cf, opticalspectroscopy of highly charged nickel ions is carried out, motivated by the two optical clock transitions present in Ni$^{12+}$. The optical emission spectroscopy performed at the HD-EBIT provides essential benchmark data for wavelength determination of prospective clock transitions, thereby laying the foundation for subsequent precision spectroscopy experiments. The wavelength of the Ni$^{12+}$ M1 transition is measured with a fractional uncertainty in the order of 10$^{-7}$. Atomic structure calculations of highly charged Cf and Ni ions are presented. The experimental nickel results agree with the calculations, confirming the reliability of the theoretical method for line identification and supporting its application to californium spectroscopy.

Note: Dissertation, Humboldt-Universität zu Berlin, 2026

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Contributing Institute(s):

1. Z_DET (Z_DET)

Research Program(s):

1. 613 - Matter and Radiation from the Universe (POF4-613) (POF4-613)

Experiment(s):

1. No specific instrument

Appears in the scientific report 2026

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