Cryogenic systems

A system for cryogenic processing comprising:

• a container comprising one or more sides and a floor forming a rectangular interior chamber with an open top, wherein a part of the chamber floor forms a sample-holding portion;
• a collar arranged to couple with the open top of the container, wherein the collar extends partially or completely over at least one dry ice retention space;
• and
• a perforated retainer positioned between the interior chamber and an interior side wall, wherein said retainer forms at least one dry ice retention space capable of holding dry ice pieces between the retainer and the interior side wall and exhausting CO2 gas directly into the interior chamber,
• wherein the system is configured to allow for access to the sample-holding portion of the chamber floor while maintaining the interior chamber at an equilibrium condition at a temperature below an ambient temperature.