Time-lapse Microtomography for the Study of Wet Snow Metamorphism

Wet snow imaging, where 3 phases (air, ice and liquid water) coexist, presently resists the tomographic approach due to several reasons: (1) the low absorption contrast between ice and liquid water, (2) the difficult temperature regulation at 0°C, and (3) some very rapid processes that may occur during ice melting and water percolation. We recently found solutions to most of these difficulties using several approaches, but our results were impacted by technical limitations. We now intend to use the ID19 beamline, whose energy range, and compatibility with our cold cell CellDyM2 is typically well suited to our experimental needs. A dry snow sample will be inserted into the cold cell that will control the sample temperature during the scans. Starting at -20°C, the sample temperature will be set to 0°C, forcing ice grains and liquid water to coexist for 3 days, allowing to observe wet snow metamorphism using time-lapse tomography.