Abstract: An athermal open-loop hung mass accelerometer configures the CTE of the sensor heads such that any growth by the body in response to a body temperature gradient along the longitudinal axis is offset by the growth of the sensor heads in the equal and opposite direction to null the effects of the temperature gradient. In many configurations, the sensor head CTE is strictly less than the body CTE and typically between 60-80% of the body CTE to null the effects of the predicted body temperature gradient.

Abstract: An athermal open-loop hung mass accelerometer configures the CTE of the sensor heads such that any growth by the body in response to a body temperature gradient along the longitudinal axis is offset by the growth of the sensor heads in the equal and opposite direction to null the effects of the temperature gradient. In many configurations, the sensor head CTE is strictly less than the body CTE and typically between 60-80% of the body CTE to null the effects of the predicted body temperature gradient.

Abstract: A system includes a cryocooler configured to cool an object, a sensor configured to measure a temperature of the object, and a controller configured to generate an actuator drive signal to control the cryocooler based on at least one temperature measurement from the sensor. The cryocooler includes a heat exchanger and a needle configured to control flow of coolant gas through the heat exchanger. The cryocooler also includes a motion rod configured to move the needle and an actuator assembly configured to move the motion rod to thereby move the needle. The actuator could include a motor and a gear head configured to rotate a lead screw and a lead screw nut located around the lead screw and configured to translate rotational motion of the lead screw into linear motion. The actuator could also include a piezoelectric actuator or a linear actuator.

Abstract: A system includes a cryocooler configured to cool an object, a sensor configured to measure a temperature of the object, and a controller configured to generate an actuator drive signal to control the cryocooler based on at least one temperature measurement from the sensor. The cryocooler includes a heat exchanger and a needle configured to control flow of coolant gas through the heat exchanger. The cryocooler also includes a motion rod configured to move the needle and an actuator assembly configured to move the motion rod to thereby move the needle. The actuator could include a motor and a gear head configured to rotate a lead screw and a lead screw nut located around the lead screw and configured to translate rotational motion of the lead screw into linear motion. The actuator could also include a piezoelectric actuator or a linear actuator.