27 July 2026

Photo: UHH

Lena Schweder has successfully completed her Bachelor's thesis and her Physics degree in our group.

For her thesis project, Lena constructed, activated, and characterised two filters for the purification of gases used in gaseous detectors: an oxygen-removing filter based on copper-oxide getter and a water-removing filter based on molecular sieves. In doing so, she helped establish the infrastructure and procedures for filter construction and activation within the group. Subsequently, using a spherical proportional counter equipped with an 11-anode ACHINOS sensor, Lena evaluated the purification performance and the radon emanation of the filters. By introducing a substantial but controlled oxygen contamination, she demonstrated that the detector signal efficiency was practically entirely lost without purification, whereas passing the same contamination through the filters largely preserved the detector response. The measured radon emanation rates of the two filters were found to be substantially lower than that of a commercial reference filter.

We congratulate Lena on her significant contributions and wish her all the best in her future research activities.