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HK: Fachverband Physik der Hadronen und Kerne

HK 40: Structure and Dynamics of Nuclei X

HK 40.5: Talk

Thursday, March 13, 2025, 15:15–15:30, HS 2 Physik

Lifetime measurements in ²⁰⁸Po using the ORANGE-spectrometer and LaBr₃(Ce) detectors — •Dania Al Daas, Andrey Andrey, Jean-Marc Regis, Nigel Warr, and Jan Jolie — IKP, University of Cologne, Germany

The iron-free high-efficiency electron-spectrometer ORANGE at the IKP University of Cologne was updated recently [1]. Using the 10 MV FN-tandem accelerator, 208Po was produced with the reaction ²⁰⁹Bi(p, 2nγ) to measure the lifetimes of the 2₁⁺, 4₁⁺ and 6₁⁺ states using e⁻-γ and γ-γ coincidence measurements. The resulting lifetimes were compared to known values to ascertain the state of the updated spectrometer. For the mono-energetic electrons, the magnetic field of the ORANGE was varied to select different electron energies for detection by a plastic scintillator counter. The γ-rays were measured by a HPGe and four LaBr₃(Ce) detectors, the latter having a fast electronic response that allows for a precise determination of the lifetime of excited states. The resulting lifetimes of all three states have a higher precision than the known lifetimes, while agreeing within the error margin [2,3].

[1] A. Harter et al., Physical Review C, 106:024326, (2022) ;

[2] D. Kalaydjieva et al., Physical Review C, 104:024311, (2021) ;

[3] V. Rahkonen et al., Z. Phys. A 322, 333-348, (1985) .

Keywords: 208Po; ORANGE spectrometer; fast timing; Lifetime measurements