Abstract: A low-temperature refrigeration system (10) is disclosed for accurately maintaining an instrument (11) with a time varying heat output at a substantially constant predetermined cryogenic temperature. The refrigeration system (10) controls the temperature of the instrument (11) by accurately adjusting the pressure of coolant at a heat exchanger interface (12) associated with the instrument (11). The pressure and flow of coolant is adjusted through the use of one or two circulation loops and/or a non-mechanical flow regulator (24) including a heater (32). The refrigeration system further provides a thermal capacitor (16) which allows for variation of the cooling output of the system (10) relative to a cooling output provided by a cooling source (14).

Abstract: A low-temperature refrigeration system (10) is disclosed for accurately maintaining an instrument (11) with a time varying heat output at a substantially constant predetermined cryogenic temperature. The refrigeration system (10) controls the temperature of the instrument (11) by accurately adjusting the pressure of coolant at a heat exchanger interface (12) associated with the instrument (11). The pressure and flow of coolant is adjusted through the use of one or two circulation loops and/or a non-mechanical flow regulator (24) including a heater (32). The refrigeration system further provides a thermal capacitor (16) which allows for variation of the cooling output of the system (10) relative to a cooling output provided by a cooling source (14).