Abstract: The temperature differential in the vapor-phase storage area of a liquid nitrogen refrigerator is reduced by producing turbulence in the nitrogen gas in the vapor-phase storage area without materially affecting the level of liquid nitrogen in the refrigerator. In one embodiment, turbulence is induced by introducing gaseous nitrogen into the refrigerator chamber near or below the level of the liquid nitrogen. In another embodiment, an atomized spray of liquid nitrogen is injected adjacent the top of the refrigerator chamber to absorb heat from the warmer nitrogen gas and to produce turbulence or circulation in the nitrogen gas in the chamber. In another embodiment, a gas circulating fan is provided in the top of the refrigeration chamber, with the fan being operated in response to a signal indicating that the temperature has reached a predetermined high level at a critical point in the chamber.