A pneumatically driven cryogenic refrigerator operating primarily on the Gifford-McMahon (GM) cycle is switched from cooling to heating by a switch valve between a rotary valve and a drive piston that causes the displacer to reciprocate. The rotary valve has ports at two radii, one that cycles flow to the displacer and a second that cycles flow to the drive piston. Two ports cycle flow to the top of the drive piston, the “cooling” port optimizes the cooling cycle and the “heating” port provides a good heating cycle. A switch valve that changes the flow from one port to the other can be linearly or rotary actuated. The rotary valve does not reverse direction.

A CO.sub.2 cooling system includes a compression stage in which CO.sub.2 refrigerant is compressed; a cooling stage in which the CO.sub.2 refrigerant releases heat; a CO.sub.2 liquid receiver in which the CO.sub.2 refrigerant is accumulated in liquid and gaseous states; an evaporation stage in which the CO.sub.2 refrigerant, having released heat in the cooling stage, absorbs heat. The evaporation stage has first and second evaporation sectors; a first metering device for feeding CO.sub.2 refrigerant into the first evaporation sector at a first pressure; and a second metering device for feeding CO.sub.2 refrigerant into the second evaporation sector at a second pressure. The first metering device and the second metering device are operated independently from one another. A plurality of CO.sub.2 transfer lines connects the compression stage, the cooling stage, the CO.sub.2 liquid receiver and the evaporation stage. The CO.sub.2 refrigerant is circulable in a closed-loop circuit.

A CO.sub.2 cooling system includes a compression stage in which CO.sub.2 refrigerant is compressed; a cooling stage in which the CO.sub.2 refrigerant releases heat; a CO.sub.2 liquid receiver in which the CO.sub.2 refrigerant is accumulated in liquid and gaseous states; an evaporation stage in which the CO.sub.2 refrigerant, having released heat in the cooling stage, absorbs heat. The evaporation stage has first and second evaporation sectors; a first metering device for feeding CO.sub.2 refrigerant into the first evaporation sector at a first pressure; and a second metering device for feeding CO.sub.2 refrigerant into the second evaporation sector at a second pressure. The first metering device and the second metering device are operated independently from one another. A plurality of CO.sub.2 transfer lines connects the compression stage, the cooling stage, the CO.sub.2 liquid receiver and the evaporation stage. The CO.sub.2 refrigerant is circulable in a closed-loop circuit.

In a cryopump, a primary cryopumping array having adsorbent and cooled by a second refrigerator stage extends along radiation shield sides. That array is shielded by a condensing cryopumping array that extends along the primary cryopumping array. The primary cryopumping array may be a cylinder with adsorbent on an inwardly facing surface, and the condensing cryopumping array may comprise an array of baffles having surfaces facing the frontal opening. A raised surface such as a conical surface at the base of the radiation shield redirects molecules received from the frontal opening toward the primary cryopumping array. The refrigerator cold finger may extend tangentially relative to the radiation shield or connect to the base of the radiation shield.

In a cryopump, a primary cryopumping array having adsorbent and cooled by a second refrigerator stage extends along radiation shield sides. That array is shielded by a condensing cryopumping array that extends along the primary cryopumping array. The primary cryopumping array may be a cylinder with adsorbent on an inwardly facing surface, and the condensing cryopumping array may comprise an array of baffles having surfaces facing the frontal opening. A raised surface such as a conical surface at the base of the radiation shield redirects molecules received from the frontal opening toward the primary cryopumping array. The refrigerator cold finger may extend tangentially relative to the radiation shield or connect to the base of the radiation shield.

The disclosure describes various aspects of a cryogenic trapped-ion system. In an aspect, a method is described that includes bringing a chain of ions in a trap at a cryogenic temperature, the trap being a micro-fabricated trap, and performing quantum computations, simulations, or both using the chain of ions in the trap at the cryogenic temperature. In another aspect, a method is described that includes establishing a zig-zag ion chain in the cryogenic trapped-ion system, detecting a change in a configuration of the zig-zag ion chain, and determining a measurement of the pressure based on the detection in the change in configuration. In another aspect, a method is described that includes measuring a low frequency vibration, generating a control signal based on the measurement to adjust one or more optical components, and controlling the one or more optical components using the control signal.

A Gifford-McMahon (GM) type double-inlet pulse tube system providing cooling at cryogenic temperatures is provided. The system has a co-axial double-inlet valve that includes a base having an adjustable port, a fixed needle partially engaged in one end of the adjustable port, an adjustable needle partially engaged in another end of said adjustable port, and a body for housing the base, the fixed needle and the adjustable needle. The base is configured to be adjustable along an axial direction. The adjustable needle is arranged co-axially with the fixed needle. The adjustable port and the adjustable needle are configured to control an alternating current (AC) flow and a direct current (DC) flow between the stem port and the end port and to produce the DC flow in either direction between the stem port and the end port.

A Gifford-McMahon (GM) type double-inlet pulse tube system providing cooling at cryogenic temperatures is provided. The system has a co-axial double-inlet valve that includes a base having an adjustable port, a fixed needle partially engaged in one end of the adjustable port, an adjustable needle partially engaged in another end of said adjustable port, and a body for housing the base, the fixed needle and the adjustable needle. The base is configured to be adjustable along an axial direction. The adjustable needle is arranged co-axially with the fixed needle. The adjustable port and the adjustable needle are configured to control an alternating current (AC) flow and a direct current (DC) flow between the stem port and the end port and to produce the DC flow in either direction between the stem port and the end port.

Dilution refrigeration device and method comprising a loop working circuit containing a working fluid comprising a mixture of helium-3 (3He) and helium-4 (4He), the working circuit comprising, arranged in series and fluidically connected via a first set of pipes, a mixing chamber, an evaporator and transfer member, the first set of pipes being configured to transfer the working fluid from an outlet of the mixing chamber to an inlet of the evaporator and from an outlet of the evaporator to an inlet of the transfer member, the working circuit comprising a second set of pipes connecting an outlet of the transfer member to an inlet of the mixing chamber, the working circuit comprising at least a first heat-exchange portion for exchange of heat between at least part of the first set of pipes and the second set of pipes, the first heat-exchange portion being situated between the evaporator and the mixing chamber, the device further comprising at least one cooling member in a heat-exchange relationship with the working circuit, the device comprising at least one cryogenic pumping member situated in the working circuit between the evaporator and the transfer member.

A refrigerator port includes a sleeve and a pedestal. A pipe is drawn out from the refrigerator port. The pipe is provided with a valve. Before a cold head is pulled out, helium gas in a tank is supplied to a port space via the pipe. Accordingly, a pressure in the port space becomes the atmospheric pressure or approaches the atmospheric pressure. A pressure adjustment facility can also function when residual gas is discharged from the port space. Thus, the load of an operation of pulling out the cold head from the refrigerator port is reduced.