Microscope Slide Cooler

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A humble microscopy cryo stage for the masses. We employ this tool to prepare air-sensitive single crystals at low temperature in an inert atmosphere, yet see no reason why it couldn't be utilized for other purposes like biological samples. The concept involves creating a cold upward N2 or air gradient over the sample, which is constantly replenished. The slide itself boasts a large contact surface with the cold gas flow, helping to maintain a consistent sample temperature. The gas is chilled by passing it through some sort of heat exchanger (LN2 or dry ice bath). Slides can be easily slotted in and out if the sample is reasonably flat (1mm clearance). The device is compact enough to be carried in a pocket. One crystal mounted on a standard sample holder can be held in the recess and locked in place, e.g. for mailing. In a test, we disconnected the device from the nitrogen flow, covered the inlet and outlet, slid on the lid, and buried it in dry ice overnight. The next day, the device could be reconnected, and manipulations continued normally with no sample damage. You'll need a standard microscopy slide, a 22x22mm slide cover for the underside window (optional, but helps prevent condensation), some grease for seating the connectors, and 4x M5x16 countersunk + hex nuts. A very simple heat exchanger setup is shown in the pictures, with LN2 in the tank and very slow flow allowing a constant temperature in the -30°C to -10°C range. Temperature control is possible but limited (maybe +/- 15° but the base temp is predetermined by the actual setup).