Köln 2025 – scientific programme

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HK: Fachverband Physik der Hadronen und Kerne

HK 23: Poster

HK 23.26: Poster

Tuesday, March 11, 2025, 17:30–19:00, Foyer Physik

Recomission of a conversion electron spectrometer with stacked Si pad detectors — •Matthias Kilb, Han-Bum Rhee, Steffen Meyer, Ilja Homm, and Thorsten Kröll — TU Darmstadt, Darmstadt, Germany

De-excitation of an excited nucleus can occur in several ways. In competition with the emission of a gamma ray, the excitation energy can also be transferred directly to a close electron, which is then emitted. In order to be able to measure such transitions, a conversion electron spectrometer is used, which uses a magnetic transport and filter system, called Mini-Orange (MO), as a central unit [1]. The MO consists of 6 wedge-shaped permanent magnets symmetrically arranged around a lead absorber with a copper cap. The resulting magnetic field makes it possible to focus electrons of a specific energy range from a wider solid angle onto a comparatively small area and to suppress interfering factors. The setup offers the possibilty to vary the distances between source, MO and detector, allowing to maximize the transmission of different electron energies.

Due to the damage of the Si(Li) detectors used previously, which were several millimeters thick, the concept of two stacked 1mm and 1.5mm thick Si pad detectors, which are easier to handle, is now being investigated. The data is read out using a digital DAQ. The results of a measurement with a ²⁰⁷Bi source and the transmission curve for electrons of approximately 975 keV of the MO are presented.

[1] D. Gassmann, Dissertation, LMU München, 2003

Keywords: Instrumentation; Silicon detectors