The main part of LINA is a silver plate with dimensions of 4cm x 4cm which is cooled by a Peltier element. A clean hydrophobic glass plate (4cm in diameter) is put onto this plate at the beginning of each experiment. A similarly sized aluminum disk (with 90 holes, each with a diameter of 2mm) is fixed on top of the glass plate, and a droplet with a volume of 1μL from the suspensions that shall be examined is pipetted into each of the holes. The aluminum disk is then covered with a second glass plate. All of this is contained in a housing, and the droplets can be viewed from top through a window. To prevent fogging of the window the housing is constantly flushed with dry air during an experiment. A camera and a circular illumination system are installed above the window.
During an experiment, droplets typically are cooled at a rate of 1K/min. Every 6s, the camera takes a picture, resulting in a temperature resolution of 0.1K. Once frozen, a droplet will not reflect the light from the illumination system as before, hence a differentiation between frozen and unfrozen droplets can easily be done automatically. This results in information on the number of frozen droplets at each temperature. The picture shown here (insert on the left in the picture above) shows 21 frozen droplets which, for that particular experiment, were reached at -24°C. Further information on the usage of the obtained data as well as on background measurements and calibrations can be found in the literature (e.g. Chen et al., 2018; Knackstedt et al, 2018). This set up was partially copied from the one described in Budke & Koop (2015).