Protective gas microscopy preparation tool

thingiverse

Human beings occasionally receive specimen vials that have been sealed under argon within a glovebox. Preparing crystals is straightforward using a MicroCHILL, as documented in this publication: https://journals.iucr.org/j/issues/2018/02/00/gj5200/gj5200.pdf. Nevertheless, transporting the samples from the vial to the stage without air contact poses a common challenge. This tool aims to resolve this issue. The vessel is shielded by a protective gas stream distributed through a ring of nozzles. I designed it around a piece of plexy pipe glued on to maintain visibility. If necessary, the gas stream can be pre-cooled by passing it through a spiral submerged in dry ice. The vial can be clamped in place with an M3 screw; ensure that the cap is unscrewed about half a turn before placing the vial. Initial tests were very promising, as it was easy to unscrew the cap using forceps and perform manipulations inside the vessel under the microscope. The provided scad file is designed for a maximum 30mm high/22mm diameter vessel and plexy pipe with OD=40, ID=34mm. The tap is 1/4" NPT (standard 6 or 8 mm pneumatic fitting as shown in the picture). Barbed adapters (6 and 8 mm) for standard lab hoses are provided as stl files, but I personally use a length of 8 mm pneumatic hose (the red part). The scad file is fairly parametric, allowing adjustments to tube diameters and maximum vessel size. It utilizes polyScrewThread.scad by aubenc: https://www.thingiverse.com/thing:8796.