A fully tritium-compatible cavity cell has been manufactured at the KIT main workshop and a tritium-dosing system based on a temperature-controlled getter has been built and characterized at the Tritium Laboratory Karlsruhe (TLK). Finally, the assembly was integrated into the laser spectroscopy infrastructure at the LaserLaB Amsterdam.
There, doctoral researchers Frank Cozijn and Meissa Diouf of VU Amsterdam were joined by KIT fellow Valentin Hermann from the TLK for setting up the equipment and for performing the measurements. Despite experimental challenges imposed by the safety measures required for the use of tritium, high-quality spectra could be recorded successfully for the first time.
A spectroscopic accuracy of 10-digits was achieved, making use of the frequency-comb and atomic clock facilities at LaserLaB. This corresponds to an accuracy three orders of magnitude better than previous measurements in tritiated hydrogen molecules. It exceeds the precision of corresponding theoretical predictions at the moment. This opens up a formidable path for benchmarking quantum electrodynamics in bound state systems for tritiated molecules.
The corresponding paper was published in Physical Review Letters.
The groups with Wim Ubachs (Vrije Universiteit Amsterdam, Department of Physics and Astronomy) and Magnus Schlösser (KIT, IAP, Tritium Laboratory Karlsruhe) have been fruitfully collaborating on the field tritium precision spectroscopy since 2017 with a total record of six publications. The work was supported by the Access Program of Laserlab-Europe.