Vibration-free cryogenic cooling

Abstract

Apparatus and methods are disclosed for vibration-free cryogenic cooling, suitable for TEM and other analytic equipment. A thermal battery includes one or more of: a cryocooler, a thermal switch, a thermal cold storage reservoir, and a cold finger. The thermal reservoir is mounted outside a sample chamber. The cold finger provides thermal coupling between the reservoir and a sample holder inside the sample chamber. In varying embodiments, sample holder and sample temperatures are regulated by a heater or by an inline variable thermal resistor. Cyclic phased operation includes cooling the reservoir, decoupling the cryocooler from the reservoir, and temperature-regulated passive vibration-free thermal energy extraction from sample to reservoir. The described system delivers a stand time of 12 hours at 20 K. Temperature regulation, a hybrid thermal switch, damping of thermal fluctuations, and material selection are described.