Sprecher
Beschreibung
In recent years, Metallic Magnetic Calorimeters (MMC) have emerged as excellent single photon detectors, exhibiting a broad spectral acceptance, ranging from a few to hundreds of keV, combined with a high energy resolution of $E/\Delta E (FWHM) \approx 6000$ [J. Geist. PhD thesis, 2020]. In combination with their fast rise time, they represent a superb tool for fundamental research in atomic physics.
Utilising these detectors, the K$\alpha$ transitions in helium-like uranium were measured in a high precision X-ray spectroscopy experiment. The experiment was performed at the CRYRING@ESR to test bound state QED calculations in the strong field regime. For the first time, all four single-photon transitions forming the K$\alpha$ peaks were identified and their energies determined in a heavy helium-like system [Ph. Pfäfflein et al 2022 Phys. Scr. 97 114005]. The findings are in good agreement with theory. However, in order to distinguish between different theoretical approaches, it is imperative to achieve a higher accuracy in the measurement of the transition energies in helium-like uranium, which can be gained via enhanced statistics. To this end, a rerun experiment was performed in the summer months of 2025. The improvements made to the measurement process and preliminary results are presented.
