Abstract: A cryogenic refrigerator includes a shell having a reciprocative displacer and an adsorbent mounted within the shell. In one embodiment, the displacer contains both a regenerative media and the adsorbent, with the regenerative media placed between the adsorbent and a cold end of the displacer. In a method for removing contaminants from the reciprocative displacer, compressed and expanded helium gas is displaced through the displacer, with the adsorbent positioned to adsorb contaminant gases entrained in the helium gas. In another method, a filtering refrigerator containing an adsorbent is coupled to a helium circuit of a refrigeration system to remove contaminants from the circuit.

Abstract: An ionization gauge including a source of electrons; an open anode defining an anode volume, where the source of electrons is disposed outside the anode volume; a plurality of ion collector electrodes disposed within the anode volume; a plurality of axially extending anode support posts for supporting the open anode, the anode support posts being electrically connected to the open anode; and the plurality of ion collector electrodes being respectively located sufficiently close to the plurality of axially extending anode support posts so as to substantially repel the electrons from the anode support posts.

Abstract: A cryopump including a radiation shield having an interior surrounded by at least one wall. The radiation shield has an opening through which gases are cryopumped into the interior. A frontal cryopanel array is positioned near the opening for condensing high boiling point gases. The radiation shield and frontal cryopanel array are cooled to a first temperature. First primary cryopanel surfaces extend near the wall within the interior of the radiation shield and are cooled to a second temperature below the first temperature for condensing low boiling point gases near the wall while leaving a central gas flow pathway from the opening past the first primary cryopanel surfaces. Second primary cryopanel surfaces cooled to about the second temperature are positioned within the interior of the radiation shield and include adsorbent for adsorbing very low boiling point gases.

Abstract: Controller circuitry and method for controlling the operation of an ionization gauge having a source of electrons, an anode, an ion collector electrode. Circuitry is provided (a) for providing an electron emission current from the electron source (b) for measuring the heating power W.sub.X of the electron source to obtain a measured value of the heating power at an unknown pressure P.sub.X and (c) measuring the ion current to the collector electrode to obtain a measured value of the positive ion current i.sub.+X at the unknown pressure. A memory is also provided for storing at least one equation for pressure, the pressure equation being obtained from a reference gauge by measuring the current i.sub.+cal to the positive ion collector electrode, the electron emission current i.sub.-cal from the electron source and the heating power W.sub.cal of the electron source of the reference gauge at selected calibration pressures P.sub.cal and selected heating powers W.sub.

Abstract: An ionization gauge including a source of electrons; an open anode defining an anode volume, where the source of electrons is disposed outside the anode volume; a plurality of ion collector electrodes disposed within the anode volume; a plurality of axially extending anode support posts for supporting the open anode, the anode support posts being electrically connected to the open anode; and the plurality of ion collector electrodes being respectively located sufficiently close to the plurality of axially extending anode support posts so as to substantially repel the electrons from the anode support posts.

Abstract: A vacuum system comprises, as an integral assembly, a vacuum pump with drive motor, a purge valve, a roughing valve and an electronic control module. A cryogenic vacuum pump and a turbomolecular vacuum pump are disclosed. The control module has a programmed processor for controlling the motor and valves and is user programmable for establishing specific control sequences. The integral electronic control module is removable from the assembly and is connected to the other devices through a common connector assembly. In the turbomolecular pump system proper introduction of a purge gas through the purge valve is detected by detecting the current load on the pump drive or by detecting foreline pressure. To test the purge gas status, the purge valve may be closed and then opened as drive current or pressure is monitored. After power failure, the controller will continue normal drive of the turbomolecular pump so long as the speed of the pump has remained above a threshold value.

Abstract: A filter standpipe is mounted within a relief conduit of a cryopump. The relief conduit is joined to an exhaust conduit, and the exhaust conduit is joined to a housing which defines a vacuum chamber. The relief conduit and exhaust conduit define passages which are in fluid communication with one another and also with the vacuum chamber. The filter standpipe extends, from where it is mounted in the relief passage into the exhaust passage. A method for installing the filter standpipe includes the steps of removing a relief valve from a mount on the end of the relief conduit, inserting the filter standpipe through the mount, and remounting the relief valve.

Abstract: A cryopump includes a refrigerator, a heat station cooled by the refrigerator, and a cryopanel mounted to the heat station. The cryopanel and at least part of the heat station are within a chamber defined by a chamber wall. A shield extends from the chamber and surrounds the cryopanel to minimize the convective flow of gas past the cryopanel.

Abstract: A cryopump having a cryopump chamber includes a purge gas valve coupled to the cryopump chamber for supplying a first quantity of warm gas to the cryopump chamber in order to purge the cryopump chamber during regeneration. A roughing valve couples the cryopump chamber to a roughing pump enabling the cryopump chamber to be roughed. An exhaust valve is coupled to the cryopump chamber for exhausting gases from the cryopump chamber during purge. A delivery valve is coupled to the exhaust valve for delivering a second quantity of warm gas directly onto surfaces of the exhaust valve for warming the surfaces of the exhaust valve.

Abstract: A cold trap includes a fluid conduit having a fluid flow path therethrough, a length along the fluid flow path and a width transverse to the fluid flow path. The width of the fluid conduit is greater than the length. A gate valve is formed integrally with the fluid flow conduit for opening and closing the fluid flow path. A cryopumping array having an outer rim surrounding a central opening is positioned within the fluid conduit downstream from the gate valve and transverse to the fluid flow path such that the fluid flow path extends through the central opening. The outer rim captures water vapor from the fluid flow path.

Abstract: An apparatus and method for monitoring the torque load condition of a cryopump motor includes a power transducer for monitoring the electrical power input to the cryopump motor. A preferred embodiment of the power transducer includes a Hall-effect multiplier which measures the instantaneous and average electrical power input to the cryopump motor to determine torque load. Another preferred embodiment includes a power transducer which measures the Power Factor of the electrical power input to the cryopump motor to determine torque load. The Power Factor transducer includes a phase detector which detects the phase difference between the input voltage and the input current applied to the cryopump motor.

Abstract: A cold trap includes a fluid conduit having a fluid flow path therethrough, a length along the fluid flow path and a width transverse to the fluid flow path. The width of the fluid conduit is greater than the length. A cryopumping array having an outer rim surrounding a central opening is positioned within the fluid conduit transverse to the fluid flow path such that the fluid flow path extends through the central opening of the array. The outer rim captures water vapor from the fluid flow path. The array has a transverse width and a rim width which are both greater than the thickness of the array. A conductive strut extends from the array through the fluid conduit transverse to the fluid flow path for a conductively coupling the array to a cryogenic cooling source which cools the array to cryogenic temperatures.

Abstract: A cryopump is regenerated by roughing the cryopump during purging. Purging and roughing is carried out in first a high temperature mode and then a lower ambient temperature mode. In the lower temperature mode, the cryogenic refrigerator is turned on. If the system fails a rough test after roughing at the lower temperature, it is repurged with the rough valve open.

Abstract: The cryopanel of a cryopump can be preferentially defrosted to remove an acid-forming or toxic gas while leaving a second gas substantially condensed upon the cryopanel thereby limiting interaction between the vapor phases of the two gases. The cryopanel is warmed to a temperature within a selective defrost range at which the first gas selectively sublimates from the cryopanel. The temperature of the cryopanel is then maintained at a temperature within this range until the cryopanel is substantially cleared of the first gas leaving the second gas substantially undisturbed as a condensate upon the cryopanel. In a preferred embodiment, the cryopanel is maintained at about 50 to 85K during standard operation before being defrosted.

Abstract: A cryopanel is formed of aluminum to avoid copper ions in a work chamber, and the aluminum is coated with a Teflon.RTM. polymer for corrosion resistance. A corrosion resistant thermally conductive link is obtained by surrounding indium with a polymer coated C-ring. The cryopanel is shaped as a trough to enable draining of liquid during regeneration.

Abstract: A cryopump includes a two-stage refrigerator, a primary pumping surface, and a radiation shield. The radiation shield is in thermal contact with the first stage of the refrigerator. The primary pumping surface is surrounded by the radiation shield and is in thermal contact, through a direct conductive link, with the second stage of the refrigerator. The refrigerator, however, is external to the radiation shield.

Abstract: A method for regulating the cooldown of multiple cryogenic refrigerators supplied with compressed refrigerant from a common compressor includes the following steps. The cooldown of the refrigerators is monitored. The cooldown of at least one refrigerator is then governed to regulate the gas flow distributed from the compressor to each of the refrigerators to enhance the cooldown of an individual refrigerator. Governing a refrigerator to achieve the objectives of this method can be achieved by various processes. These processes include supplying heat to the refrigerator, slowing the speed of the displacer in the refrigerator, halting the motion of the displacer, and profiling the speed of the displacer as a function of the first and second-stage temperatures.

Abstract: A method for detecting the absence of a pressure differential across a cryogenic refrigerator includes the following steps. At least one measurement of load in the refrigerator is taken during both a warmstroke and a coldstroke of a refrigeration cycle. These measurements are then compared to determine whether the differential load across the cryogenic refrigerator has been lost. A system for performing this method includes a compressor that circulates compressed gas through a compressed gas line routed through a cryogenic refrigerator. Within the refrigerator, a displacer is driven through a refrigeration cycle by a motor. A means for measuring the load on the motor is provided, and an electronic module monitors the load measurements to detect a loss of differential pressure across the refrigerator by comparing the load on the motor during the warmstroke to the load on the motor during the coldstroke.

Abstract: A drive for driving a displacer in a cryogenic refrigerator includes a rotatable cam having a cam surface. The cam is rotatable about a pivot point with a cam follower contacting the cam surface. Rotational motion of the cam is converted into reciprocating motion of the cam follower. A displacer rod is coupled between the cam follower and the displacer for transferring the reciprocating motion of the cam follower to the displacer for driving the displacer.

Abstract: A cryopump includes a refrigerator, a heat station cooled by the refrigerator, and a cryopanel mounted to the heat station. The cryopanel and at least part of the heat station are within a chamber defined by a chamber wall. A shield extends from the chamber and surrounds the cryopanel to minimize the convective flow of gas past the cryopanel.