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M.Sc. Mario Schwarz

+49 89 289-12475
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Experimental Astro-Particle Physics

Courses and Dates

Offered Bachelor’s or Master’s Theses Topics

Xenon doped liquid argon - mixing, measuring, modeling
At the first glance, liquid argon as a detector material might seem to be a peculiar choice: its low boiling point of 87 K makes it difficult to handle and puts hard constraints on any material touching it. Nonetheless, many experiments in the field of astroparticle physics employ it as a detection medium - from dark matter search to neutrinoless double beta decay. This is due to its superior properties as a scintillation medium. Via the scintillation process, energy depositions (e.g. from a dark matter particle scattering off a nucleus or gamma particles interacting) lead to light emission in the liquid argon volume. A high light output is key for a good energy reconstruction, as exhibited by liquid argon. Current efforts are made in doping liquid argon with small traces of Xenon (at parts-per-million levels), in order to further enhance the light output. Properties like the time spectrum and total light output of the light emitted by this noble gas mixture are not sufficiently understood as of now. Measurement runs in a 1m³ liquid argon cryostat located in a shallow underground lab at TUM are conducted to study these effects at various Xenon concentrations. An optical detection and monitoring system (LLAMA) is used to obtain time-resolved optical properties. The Bachelor candidate works on the modeling of the light emission process of this Xe-Ar-mixture using data obtained so far. Furthermore, they will take part in setting up, conducting and analyzing data obtained in a new measurement run planned to commence in June 2022. As the work includes the fitting of data present in ROOT format, basic C++ skills are beneficial, but not required. Skills in programming, data analysis and modeling are acquired by the student, in addition to knowledge in the handling of gas and cryogenic liquids by hands-on laboratory work. The theses can be carried out at the Chair for astroparticle physics of the Physics Department. Supervision at the Physics Deptartment by Prof. Schönert and Mario Schwarz. Please contact or for further information. We will organize a dedicated meeting for interested students on Tuesday, February 1, 14:00-16:00. For more information please check
suitable as
  • Bachelor’s Thesis Physics
Supervisor: Stefan Schönert
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