Abstract: A Gifford-McMahon cryogenic refrigerator comprises a reciprocating displacer within a refrigeration volume. The displacer is pneumatically driven by a drive piston within a pneumatic drive volume. Pressure in the pneumatic drive volume is controlled by valving that causes the drive piston to follow a programmed displacement profile through stroke of the drive piston. The drive valving may include a proportional valve that provides continuously variable supply and exhaust of drive fluid. In a proportionally controlled feedback system, the valve into the drive volume is controlled to minimize error between a displacement signal and a programmed displacement profile. Valving to the warm end of the refrigeration volume may also be proportional. A passive force generator such as a mechanical spring or magnets may apply force to the piston in opposition to the driving force applied by the drive fluid.

Abstract: A capacitive manometer offering improved measurement accuracy is disclosed which includes at least one electrode structure having an inner electrode structure and an outer electrode structure separated by at least one gap, at least one flexible diaphragm having at least one conductive material positioned thereon or integrated therein may be positioned in movable relation to the electrode structure and in proximity to the electrode structure, and at least one non-planar baffle less prone to transient measurement errors having an inner baffle structure and an outer baffle structure separated by at least one baffle orifice positioned distantly from the electrode structure proximate to the flexible diaphragm.

Abstract: A Gifford-McMahon cryogenic refrigerator comprises a reciprocating displacer within a refrigeration volume. The displacer is pneumatically driven by a drive piston within a pneumatic drive volume. Pressure in the pneumatic drive volume is controlled by valving that causes the drive piston to follow a programmed displacement profile through stroke of the drive piston. The drive valving may include a proportional valve that provides continuously variable supply and exhaust of drive fluid. In a proportionally controlled feedback system, the valve into the drive volume is controlled to minimize error between a displacement signal and a programmed displacement profile. Valving to the warm end of the refrigeration volume may also be proportional. A passive force generator such as a mechanical spring or magnets may apply force to the piston in opposition to the driving force applied by the drive fluid.

Abstract: A heat exchanger within an insulated enclosure receives primary refrigerant at a high pressure and cools the primary refrigerant using a secondary refrigerant from a secondary refrigeration system. An expansion unit within the insulated enclosure receives the primary refrigerant at the high pressure from the heat exchanger and discharges the primary refrigerant at a low pressure. A supply line delivers the primary refrigerant at the low pressure to the load and a return line returns the primary refrigerant from the load to the primary refrigeration system. A system control unit controls operation of at least one of the primary refrigeration system and the secondary refrigeration system to provide a variable refrigeration capacity to the load based on at least one of: a pressure of the primary refrigerant delivered to the load, and at least one temperature of the load.

Abstract: A Gifford-McMahon cryogenic refrigerator comprises a reciprocating displacer within a refrigeration volume. The displacer is pneumatically driven by a drive piston within a pneumatic drive volume. Pressure in the pneumatic drive volume is controlled by valving that causes the drive piston to follow a programmed displacement profile through stroke of the drive piston. The drive valving may include a proportional valve that provides continuously variable supply and exhaust of drive fluid. In a proportionally controlled feedback system, the valve into the drive volume is controlled to minimize error between a displacement signal and a programmed displacement profile. Valving to the warm end of the refrigeration volume may also be proportional. A passive force generator such as a mechanical spring or magnets may apply force to the piston in opposition to the driving force applied by the drive fluid.

Abstract: A capacitance manometer is disclosed which includes at least one electrode structure having an inner electrode structure and an outer electrode structure separated by at least one gap, at least one flexible diaphragm having at least one conductive material positioned thereon or integrated therein may be positioned in movable relation to the electrode structure and in proximity to the electrode structure, and at least one non-planar baffle having an inner baffle structure and an outer baffle structure separated by at least one baffle orifice positioned distantly from the electrode structure proximate to the flexible diaphragm.

Abstract: A Gifford-McMahon cryogenic refrigerator comprises a reciprocating displacer within a refrigeration volume. The displacer is pneumatically driven by a drive piston within a pneumatic drive volume. Pressure in the pneumatic drive volume is controlled by valving that causes the drive piston to follow a programmed displacement profile through stroke of the drive piston. The drive valving may include a proportional valve that provides continuously variable supply and exhaust of drive fluid. In a proportionally controlled feedback system, the valve into the drive volume is controlled to minimize error between a displacement signal and a programmed displacement profile. Valving to the warm end of the refrigeration volume may also be proportional. A passive force generator such as a mechanical spring or magnets may apply force to the piston in opposition to the driving force applied by the drive fluid.

Abstract: A cryopump includes a refrigerator with at least first and second stages. A radiation shield surrounds the second stage and is in thermal contact with the first stage. The radiation shield includes a drain hole to permit cryogenic fluid to traverse through the drain hole during regeneration. The cryopump also includes a primary pumping surface supporting adsorbent in thermal contact with the second stage. The second stage array assembly includes a primary condensing surface, protected surfaces having adsorbent, and non-primary condensing surfaces. A baffle is disposed over the drain hole. The baffle redirects gas from an annular space disposed between the radiation shield and the vacuum vessel that attempts to traverse through the drain hole to prevent the gas from condensing on a non-primary condensing surface. The baffle directs gas to condense on the primary condensing surface.

Abstract: A refrigerator system or cryopump includes a first refrigerator having at least first and second stages, and a second refrigerator. A thermal coupling between the first stage of the first refrigerator and a cold end of the second refrigerator is restricted to maintain a temperature difference between the cold end of the second refrigerator and the first stage of the first refrigerator. The refrigerator system or cryopump also includes a radiation shield in thermal contact with the cold end of the second refrigerator, and a condensing surface, spaced from and surrounded by the radiation shield, and in thermal contact with a second stage, e.g., coldest stage, of the first refrigerator. The restricted thermal coupling can be configured to balance the cooling load on the two refrigerators.

Abstract: A heat exchanger within an insulated enclosure receives primary refrigerant at a high pressure and cools the primary refrigerant using a secondary refrigerant from a secondary refrigeration system. An expansion unit within the insulated enclosure receives the primary refrigerant at the high pressure from the heat exchanger and discharges the primary refrigerant at a low pressure. A supply line delivers the primary refrigerant at the low pressure to the load and a return line returns the primary refrigerant from the load to the primary refrigeration system. A system control unit controls operation of at least one of the primary refrigeration system and the secondary refrigeration system to provide a variable refrigeration capacity to the load based on at least one of: a pressure of the primary refrigerant delivered to the load, and at least one temperature of the load.

Abstract: In accordance with an embodiment of the invention, there is provided a system for cooling a load.

Abstract: A cryopump has a simple-to-manufacture frontal baffle plate with improved gas distribution and has a large-area second-stage array plate to capture Type II gases. The cryopump has a first-stage frontal baffle plate having orifices and flaps bent from and attached to the orifices. The cryopump has a second-stage top plate that is larger in area than cooling baffles of the second stage array.

Abstract: A refrigerator system or cryopump includes a first refrigerator having at least first and second stages, and a second refrigerator. A thermal coupling between the first stage of the first refrigerator and a cold end of the second refrigerator is restricted to maintain a temperature difference between the cold end of the second refrigerator and the first stage of the first refrigerator. The refrigerator system or cryopump also includes a radiation shield in thermal contact with the cold end of the second refrigerator, and a condensing surface, spaced from and surrounded by the radiation shield, and in thermal contact with a second stage, e.g., coldest stage, of the first refrigerator. The restricted thermal coupling can be configured to balance the cooling load on the two refrigerators.

Abstract: A refrigerator system or cryopump includes a first refrigerator having at least first and second stages, and a second refrigerator. A thermal coupling between the first stage of the first refrigerator and a cold end of the second refrigerator is restricted to maintain a temperature difference between the cold end of the second refrigerator and the first stage of the first refrigerator. The refrigerator system or cryopump also includes a radiation shield in thermal contact with the cold end of the second refrigerator, and a condensing surface, spaced from and surrounded by the radiation shield, and in thermal contact with a second stage, e.g., coldest stage, of the first refrigerator. The restricted thermal coupling can be configured to balance the cooling load on the two refrigerators.

Abstract: A cryopump has a simple-to-manufacture frontal baffle plate with improved gas distribution and has a large-area second-stage array plate to capture Type II gases. The cryopump has a first-stage frontal baffle plate having orifices and flaps bent from and attached to the orifices. The cryopump has a second-stage top plate that is larger in area than cooling baffles of the second stage array.

Abstract: A cryopump has a simple-to-manufacture frontal baffle plate with improved gas distribution and has a large-area second-stage array plate to capture Type II gases. The cryopump has a first-stage frontal baffle plate having orifices and flaps bent from and attached to the orifices. The cryopump has a second-stage top plate that is larger in area than cooling baffles of the second stage array.

Abstract: An apparatus including a controller, a workpiece transport in communication with the controller having a movable portion and a transport path, and a multi-dimensional position measurement device including at least one field generating platen attached to the movable portion and at least one sensor group positioned along the transport path and in communication with the controller, the field generating platen is configured for position measurement and propelling the movable portion, each sensor in the at least one sensor group is configured to provide but one output signal along a single axis corresponding to a sensed field generated by the at least one field generating platen and the controller is configured calculate a multi-dimensional position of the movable portion based on the but one output signal of at least one of the sensors in the at least one sensor group, the multi-dimensional position including a planar position and a gap measurement.

Abstract: A cryopump has a simple-to-manufacture frontal baffle plate with improved gas distribution and has a large-area second-stage array plate to capture Type II gases. The cryopump has a first-stage frontal baffle plate having orifices and flaps bent from and attached to the orifices. The cryopump has a second-stage top plate that is larger in area than cooling baffles of the second stage array.

Abstract: An apparatus including a controller, a workpiece transport in communication with the controller having a movable portion and a transport path, and a multi-dimensional position measurement device including at least one field generating platen attached to the movable portion and at least one sensor group positioned along the transport path and in communication with the controller, the field generating platen is configured for position measurement and propelling the movable portion, each sensor in the at least one sensor group is configured to provide but one output signal along a single axis corresponding to a sensed field generated by the at least one field generating platen and the controller is configured calculate a multi-dimensional position of the movable portion based on the but one output signal of at least one of the sensors in the at least one sensor group, the multi-dimensional position including a planar position and a gap measurement.

Abstract: An apparatus including a controller, a workpiece transport in communication with the controller having a movable portion and a transport path, and a multi-dimensional position measurement device including at least one field generating platen attached to the movable portion and at least one sensor group positioned along the transport path and in communication with the controller, the field generating platen is configured for position measurement and propelling the movable portion, each sensor in the at least one sensor group is configured to provide but one output signal along a single axis corresponding to a sensed field generated by the at least one field generating platen and the controller is configured calculate a multi-dimensional position of the movable portion based on the but one output signal of at least one of the sensors in the at least one sensor group, the multi-dimensional position including a planar position and a gap measurement.