Freiburg 2024 – scientific programme

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A: Fachverband Atomphysik

A 30: Precision Spectroscopy of Atoms and Ions IV (joint session A/Q)

A 30.4: Talk

Thursday, March 14, 2024, 15:15–15:30, HS 1098

Sensitivity of Project 8's wire detector for an atomic tritium beam — •Darius Fenner and Martin Fertl — Institut für Physik, Johannes Gutenberg-Universität Mainz, Mainz, Deutschland

The Project 8 experiment aims to achieve a sensitivity of 40 meV on the neutrino mass through precise measurements of the tritium beta spectrum near its endpoint. To achieve the required energy resolution, the production of atomic tritium is imperative because it has no molecular final state distribution. Such a distribution, caused by vibrational and rotational modes of the molecules, smears the energy spectrum. At the setup in Mainz the thermal dissociation of hydrogen instead of tritium is studied. The efficiency of this process is quantified using a wire detector equipped with three 5μm tungsten wires. As atomic hydrogen recombines on the wire surface and releases the recombination energy, the temperature change of the wire is measured as a resistance change. However, the measured signal depends on the position along the wire, as heat can more readily dissipate near the mountings. In this work, the wire's sensitivity curve is determined as a function of wire position. The measurement process involves a 2D scan of the wire while performing pointwise heating with a laser. Moreover, the sensitivity is simulated in a COMSOL heat transfer simulation to complement the experimental findings.

Keywords: neutrino mass; atomic hydrogen; beam analytics