A cryopump comprises a refrigerator, a condensing array cooled by the refrigerator, a radiation shield surrounding the condensing array and cooled by the refrigerator. The radiation shield has a frontal opening covered by a frontal array that is also cooled by the refrigerator. The frontal array comprises louvers across an otherwise substantially open center region of the frontal opening and an orifice plate across an outer region of the frontal opening. The hybrid frontal array allows for pumping speeds approximating those of a louver frontal array but with flow control comparable to an orifice plate.

A cryopumped gas amount estimation device includes: an ultimate pressure determination unit which determines an ultimate pressure of a cryopump vacuum vessel, based on a vacuum measurement signal representing the degree of vacuum in the cryopump vacuum vessel; and a cryopumped gas amount quantification unit which includes a cryopumped gas amount quantification relation correlating the ultimate pressure with a cryopumped gas amount estimated value and converts the ultimate pressure into the cryopumped gas amount estimated value.

A cryopumped gas amount estimation device includes: an ultimate pressure determination unit which determines an ultimate pressure of a cryopump vacuum vessel, based on a vacuum measurement signal representing the degree of vacuum in the cryopump vacuum vessel; and a cryopumped gas amount quantification unit which includes a cryopumped gas amount quantification relation correlating the ultimate pressure with a cryopumped gas amount estimated value and converts the ultimate pressure into the cryopumped gas amount estimated value.

A compressor unit includes a flow control valve controlling a flow rate of a bypass pipe according to a valve command signal, a compressor inverter, and a controller. A range of operation frequency values is limited to a first operation frequency interval from a lower limit value to a first value and a second operation frequency interval from a second value to an upper limit value. When a target flow rate is between a first discharge flow rate and a second discharge flow rate, the controller generates an inverter command signal such that the operation frequency is set to the second operation frequency interval, and generates the valve command signal such that the flow rate of the bypass pipe coincides with a differential flow rate obtained by subtracting the target flow rate from a discharge flow rate of a compressor body obtained by the inverter command signal.

A compressor unit includes a flow control valve controlling a flow rate of a bypass pipe according to a valve command signal, a compressor inverter, and a controller. A range of operation frequency values is limited to a first operation frequency interval from a lower limit value to a first value and a second operation frequency interval from a second value to an upper limit value. When a target flow rate is between a first discharge flow rate and a second discharge flow rate, the controller generates an inverter command signal such that the operation frequency is set to the second operation frequency interval, and generates the valve command signal such that the flow rate of the bypass pipe coincides with a differential flow rate obtained by subtracting the target flow rate from a discharge flow rate of a compressor body obtained by the inverter command signal.

A cryopump includes a cryocooler which includes a high-temperature cooling stage and a low-temperature cooling stage, a radiation shield which is thermally coupled to the high-temperature cooling stage and axially extends in a tubular shape from a cryopump intake port, a low-temperature cryopanel section which is thermally coupled to the low-temperature cooling stage, is surrounded by the radiation shield, and includes axially arranged cryopanels including a top cryopanel disposed closest to the cryopump intake port, and a top cryopanel accommodation cryopanel which is thermally coupled to the high-temperature cooling stage and is disposed in the cryopump intake port to form a top cryopanel accommodation compartment.

A cryopump includes a cryocooler which includes a high-temperature cooling stage and a low-temperature cooling stage, a radiation shield which is thermally coupled to the high-temperature cooling stage and axially extends in a tubular shape from a cryopump intake port, a low-temperature cryopanel section which is thermally coupled to the low-temperature cooling stage, is surrounded by the radiation shield, and includes axially arranged cryopanels including a top cryopanel disposed closest to the cryopump intake port, and a top cryopanel accommodation cryopanel which is thermally coupled to the high-temperature cooling stage and is disposed in the cryopump intake port to form a top cryopanel accommodation compartment.

A cryopump includes a cryocooler which includes a high-temperature cooling stage and a low-temperature cooling stage, a radiation shield which is thermally coupled to the high-temperature cooling stage and axially extends in a tubular shape from a cryopump intake port, and a low-temperature cryopanel section which is thermally coupled to the low-temperature cooling stage, is surrounded by the radiation shield, and includes a plurality of cryopanels and a plurality of heat transfer bodies axially arranged in columnar shape, and in which the plurality of cryopanels and the plurality of heat transfer bodies are axially stacked.

A cryopump includes a cryocooler which includes a high-temperature cooling stage and a low-temperature cooling stage, a radiation shield which is thermally coupled to the high-temperature cooling stage and axially extends in a tubular shape from a cryopump intake port, and a low-temperature cryopanel section which is thermally coupled to the low-temperature cooling stage, is surrounded by the radiation shield, and includes a plurality of cryopanels and a plurality of heat transfer bodies axially arranged in columnar shape, and in which the plurality of cryopanels and the plurality of heat transfer bodies are axially stacked.

Apparatus for compressing cryogenic fluid in at least one compression stage comprising at least one piston and at least one sleeve delimiting at least one compression chamber, a shaft that is able to move in translation along a longitudinal axis (A), the shaft being connected to the piston(s) or sleeve(s) and being able to move with an alternating movement in two opposite directions to ensure phases of compression and intake of fluid into the at least one compression chamber by moving the at least one piston and the at least one sleeve in a relative manner, characterized in that the shaft comprises a portion of reduced cross section in the longitudinal direction (A), said portion of reduced cross section separating two adjacent parts of the shaft, the shaft also comprising at least one linking element made of material that is less thermally conductive than the constituent material of the shaft, in particular a composite material, said at least one linking element having two ends connected respectively to the two adjacent parts of the shaft.