The application relates to a cryogenic machine of the regenerative type, comprising: a pressure oscillator, at least one cold finger (20) in fluid connection with the pressure oscillator,

wherein the pressure oscillator comprises a centrifugal compressor (1) and a fluid distribution member (12) configured to alternately distribute high-pressure and low-pressure working fluid from the centrifugal compressor into said cold finger.

A double-inlet valve for a Gifford-McMahon (GM) type double-inlet pulse tube cryocooler system for providing cooling at cryogenic temperatures includes a fixed restrictor and a needle valve coupled to the fixed restrictor in parallel. The needle valve produces asymmetric flow. The combination of the fixed restrictor and the needle valve having an asymmetric flow provides improved alternating current (AC) flow characteristics and adjustability of direct current (DC) flow to increase the available cooling.

Various embodiments are directed to a pulse tube cooler. The pulse tube cooler may comprise a fluid compressor, a first regenerator, a first pulse tube, a first reservoir, a second regenerator, a second pulse tube, and a second reservoir. The first end of the first regenerator may be in fluid communication with the fluid compressor. The cold end of the first pulse tube may be in fluid communication with the second end of the first regenerator. The first reservoir may be in fluid communication with the hot end of the first pulse tube. The first end of the second regenerator may be in fluid communication with the cold end of the first regenerator. The cold end of the second pulse tube may be in fluid communication with the second end of the second regenerator. The cold end of the first pulse tube and the hot end of the second pulse tube may be in fluid communication with one another through the second reservoir.