I do not have much idea in the field, but I hope arrangement of a *cryogenic vacuum system* may help to trap liquid nitrogen on the sample surface.

The trick is that you are using the liquid N2 to cool down e.g. a Cu tube or "finger" to low temperature. This has been applied many decades for EDS detectors used in SEM or TEM (before multi-step Peltier cooling systems), but also for the upper mentioned cooling or cryo-stages.

You will need something like a head sink (see the attached images) to fix the sample on.

Or you will need connect (get a contact) between such head sink and your sample holder.

The 2017 chemistry nobel prize sounds like on this topic. :).

Thank you very much for answers