For certain applications, we want to study the optical response of hydrogen sensing materials (and sensors) at temperatures down to -60 °C. For this, we developed a dedicated set-up inside a freezer. The setup contains of a small pressure cell located in the center of the freezer to which two fiber feedthroughs are attached. One fiber is connected to a light source and another one to a spectrometer. This allows us to determine the optical transmission or reflectivity of one sample on a glass substrate inside the cell. Differently, one can also connect an optical fiber inside the cell to measure the optical response thereof.
The set-up can be operate in two modes: either (i) one gas is selected and the absolute pressure can be varied between 0-10 bar or (ii) at a fixed pressure flow controllers can be used to mix up to three different gasses together in different ratios. For example, hydrogen can be mixed with Ar in various ratio’s to expose the sample to different hydrogen concentrations.
TU Delft Optical Hydrogen Sensing & Thin Film Energy Materials 