NOVELTY - The method involves mixing a liquid cryogen with warmer gas to produce cold cryogenic gas at a selected temperature profile. A unidirectional flow of cold cryogenic gas is delivered through the gas distribution surface to the cooling area between parallel gas distribution and gas collection surface, and parallel to container to uniformly cool biological material within the container. The gas from cooling chamber (52) is exhausted through gas collection surface so as to prevent recirculation of gas within cooling area, to achieve greater uniformity of biological material in container.    USE - Method for controlling chilling or freezing process of biological material such as microorganism, tissue, organ, stem cell, primary cell, cell line, small multicellular organism, complex cellular structure, live or attenuated virus, nucleic acid, monoclonal antibody, polyclonal antibody, biomolecule, non-peptide analogue, peptide, protein, RNA, DNA, oligonucleotide, and/or viral particles (all claimed) within container such as vial, straw, polymeric bag, or other suitable container.    ADVANTAGE - The gas from cooling chamber is exhausted through gas collection surface, so as to prevent recirculation of gas within cooling area, and thus greater uniformity of biological material in container can be achieved. The rapid cooling of biological materials is achieved by precisely controlling and adjusting the temperature of the cryogen introduced to the system. The cell damage resulting from intercellular ice formation and solute effects that arise during cryopreservation process can be minimized. Cooling or freezing the biological material at the optimized rate can enhance the survival rate of the cells. The manufacturing cost can be reduced and process of freeze-dried pharmaceutical can be implemented easily. The product losses can be reduced without contaminating the lyophilized product and also the processing time can be minimized.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for a cooling unit.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic view of a multi-batch or large commercial scale uniform flow-cooling chamber.    Multi-batch or commercial scale unit (50)    Cooling chamber (52)    Shelf (54)    Cryogenic chiller (60)    Control system (70)