Development of a cryogenic DC-DC Boost Converter: devices characterization and first prototype measurements

Within the development of the second DUNE far detector module, based on the liquid argon time projection chamber technology, the development of new solutions for the photon detection system (PDS) readout and bias arose. The Vertical Drift (VD) design proposes a PDS installed on the cathode plane that is biased at high voltage (300 kV), thus preventing any electrical connection between the Silicon PhotoMultipliers (SiPM) installed in the PDS and the outside interface. The chosen solution is to provide the power through optical fibers, implementing for the first time Power over Fiber (PoF) technology in the field of cryogenic experiments. The optical to electrical converters commercially available give an output voltage of a few volts and a step-up converter is needed to provide SiPM with a supply voltage that can be set around 48 V. The design of a cryogenic boost DC-DC converter, the main components selection and their characterization at cryogenic temperature is presented in this paper. Furthermore, a first DC-DC prototype qualification is shown along with the outlook on the next steps of this work.