Gas Analyzer System with Ion Source

Abstract

The gas analyzer system uses an ion source that can be a hot cathode ion source. A positioning magnet assembly is used to define a magnetic field, and the magnet assembly allows the separation of ion components based on the mass-to-charge ratio of their ions. An ion beam deflector, such as a pair of deflection plates, can be used to scan the ion components across the detector. The ion beam deflector defines a deflection electric field across the magnetic field and across the direction of travel of the ions emitted by the ion source.

Description

[0001] Related Applications

[0002] This application is a continuation-in-part of and claims priority to U.S. Non - Provisional Application No. 16 / 698,178, filed on November 27, 2019. The entire teachings of the above application are incorporated herein by reference. BACKGROUND OF THE INVENTION

[0003] There is a continuing need to facilitate fault checking in high - vacuum processes. High - vacuum processes typically follow a workflow that begins with evacuating a vacuum chamber from atmospheric pressure. A user can track the pressure of the vacuum chamber during evacuation, and when the total pressure meets a target pressure, the vacuum process or experiment can be started. It is generally expected that the target pressure will be met within a predetermined time frame. If the target pressure is not reached after the expected time period, or if it takes longer than usual to reach the target pressure, the vacuum system user needs to perform a fault check on the vacuum chamber. Typically, a fault check requires not only the use of an ionization vacuum gauge, but also breaking the vacuum to use a helium leak detector, and sometimes also an expensive Residual Gas Analyzer to measure water levels.

[0004] Accordingly, there is a continuing need to provide equipment that reduces the time and expense involved in fault checking high - vacuum processes. Additionally, there is a need for improved systems for helium leak detection, water percentage determination, magnetic sectors, quadrupole mass filters, and other systems that use ion sources. SUMMARY OF THE INVENTION

[0005] A gas analyzer system uses an ion source, which can be a hot - cathode ion source; a magnet assembly positioned to define a magnetic field, the magnet assembly allowing separation of ion components based on the mass - to - charge ratio of their ions; and an ion beam deflector, such as a pair of deflection plates, that can scan the ion components across a detector. The ion beam deflector defines a deflection electric field across the magnetic field and across the direction of travel of the ions emitted from the ion source. This configuration can provide ions with a narrow energy distribution, which can produce a mass spectrum with sharp peaks and high resolution. Other advantages are described further below.

[0006] The gas analyzer system includes an ion source configured to establish a source electric field in an ion region of the ion source. The ion region receives gas from a monitoring chamber such that ions of the gas are formed in the ion source. A source aperture is positioned to emit a portion of the gas ions out of the ion source, and the plasma is accelerated in a direction toward the source aperture by the source electric field. A magnet assembly is positioned to define a magnetic field to angularly displace the emitted portion of the ions based on the mass-to-charge ratio of the gas ions. An ion beam deflector is positioned between the source aperture and the detector, and the ion beam deflector defines a deflection electric field that traverses the magnetic field and the direction of travel of the emitted portion of the ions. A detector is positioned to detect the displaced ion component of the emitted portion of the ions. An ion current measurement circuit means is electrically connected to measure the current generated by the displaced ion component received by the detector.

[0007] The ion source may include a cold cathode ion source or a hot cathode ion source. The hot cathode ion source may include a hot filament and an electron collector configured to establish an electron beam of the ion source passing between the hot filament and the electron collector. The hot filament and the electron collector may be configured to establish the electron beam in a direction parallel to the source aperture, and the source aperture includes an aperture elongated in a direction parallel to the electron beam. The system may further include an energy filter. The source aperture may include an elongated aperture, and the energy filter may include an energy filter grid positioned in the ion beam path of the emitted portion of the ions, and the energy filter grid includes conductive filaments oriented substantially perpendicular to the elongated aperture of the source aperture and substantially no conductive filaments oriented substantially parallel to the elongated aperture of the source aperture. The energy filter may include an inlet grid positioned between the source aperture and the inlet of the ion beam of the emitted portion of the ions into the ion beam deflector; and may include an outlet grid positioned between the outlet of the ion beam of the emitted portion of the ions exiting the ion beam deflector and the detector aperture.

[0008] The ion beam deflector may be configured to align the ion beam of the emitted portion of the ions on the detector. The ion beam deflector may include a pair of parallel plates and may include a pair of curved plates. The source aperture may be positioned to emit a portion of the gas ions from the ion source to enter the ion beam deflector closer to one side of the ion beam deflector than to the geometric center of the ion beam deflector. A deflector power supply may be electrically connected to the ion beam deflector to establish a deflection electric field between a pair of deflection plates of the ion beam deflector. The deflector power supply may be electrically connected to (i) provide a positive deflector bias voltage to the first deflection plate of the ion beam deflector with respect to the ground voltage of the second deflection plate of the ion beam deflector, or (ii) provide a negative deflector bias voltage to the first deflection plate with respect to the ground voltage of the second deflection plate, or (iii) provide a first deflector bias voltage to the first deflection plate and a second deflector bias voltage to the second deflection plate.

[0009] The deflector control circuit can be configured to supply a deflector control signal to the deflector power supply. The deflector control circuit can be configured to control the voltage of the deflector power supply to cause the ion beam deflector to direct displaced ion components having different energies and a common ionic component mass to be focused through the detector aperture of the detector. The deflector control circuit can be configured to vary the voltage of the deflector power supply to cause the ion beam deflector to vary the deflection of the displaced ion components of the emission portion of the ions. The voltage of the deflector power supply can be varied based on (i) a triangular sawtooth variation of the voltage over time, or (ii) a voltage waveform, to control the peak width and time position of the displaced ion components relative to other ion components. The deflector control circuit can be configured to scan the voltage of the deflector power supply to cause the ion beam deflector to continuously deflect a plurality of ion components detected by the detector when scanning the voltage of the deflector power supply; and can be configured to scan the voltage of the deflector power supply to permit mass spectrometry of the plurality of ion components. A total current measurement circuit device can be electrically connected to measure the total ion current of the ion source. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The foregoing will become more particularly apparent from the following detailed description of the exemplary embodiments, as illustrated in the accompanying drawings, wherein like reference characters refer to the same parts throughout the different views. The drawings are not necessarily to scale, but emphasis is placed upon illustrating the embodiments.

[0011] Figure 1 is a top view of a gas analyzer system in accordance with an embodiment of the present invention, showing internal components within a cross-sectional view of the housing.

[0012] Figure 2 is Figure 1 a perspective view of the exterior of the housing of the gas analyzer system, showing a magnet assembly used in conjunction with the gas analyzer system in accordance with an embodiment of the present invention.

[0013] Figure 3 is in accordance with an embodiment of the present invention Figure 1 a perspective side view of the inner components and sidewalls of the gas analyzer system.

[0014] Figure 4 is in accordance with an embodiment of the present invention Figure 1 a perspective view of the ion source of the gas analyzer system.

[0015] Figure 5 is in accordance with an embodiment of the present invention Figure 1 a side view of the inner components and sidewalls of the gas analyzer system.

[0016] Figure 6 is in accordance with an embodiment of the present invention Figure 1 a top view of the inner components and sidewalls of the gas analyzer system.

[0017] Figure 7 is a schematic diagram according to an embodiment of the present invention, showing the eccentric operation of a deflection plate.

[0018] Figure 8 is a schematic diagram of a gas analyzer system according to an embodiment of the present invention, showing electrical components and an ion beam path through a magnetic field.

[0019] Figure 9 is a schematic perspective view of a gas analyzer system according to an embodiment of the present invention, which uses an ion beam deflector to deflect an ion component to be detected by a detector.

[0020] Figure 10 is a schematic diagram according to an embodiment of the present invention, showing energy focusing using a deflection plate.

[0021] Figure 11 is a schematic perspective view of a gas analyzer system according to an embodiment of the present invention, which uses an inverted magnetron cold cathode discharge electrode configuration and an ion beam deflector to deflect an ion component to be detected by a detector.

[0022] Figure 12 is a schematic diagram of an ion beam deflector including a pair of curved plates according to an embodiment of the present invention. Detailed Description

[0023] The following describes exemplary embodiments.

[0024] In a prior application named to some of the inventors of the present application, a cold cathode ion source for a gas analyzer system was disclosed; see U.S. Patent Application No. 16 / 397,436, titled "Gas Analysis with a Reverse Magnetron Source," filed on April 29, 2019, by Brucker et al., the entire teachings of which are incorporated herein by reference. The disclosure of that application teaches the use of a cold cathode ion source with a magnetic field oriented transverse to an electric field, and the use of an ion beam deflector to allow an ion beam and ion components to sweep across a detector aperture, thereby allowing the generation of a spectrum of ion components.

[0025] Although the cold cathode ion source taught in this application provides many benefits, the teachings of this application can be extended to hot cathode ion sources. Similarly, additional features can be applied to both hot cathode and cold cathode ion sources. This document teaches a gas analyzer system using an ion source, which can be a hot cathode ion source. A magnet assembly is positioned to define a magnetic field that allows separation of ion components based on the mass-to-charge ratio of the ion components. An ion beam deflector, such as a pair of deflection plates, can scan the ion components across the detector. The ion beam deflector defines a deflection electric field across the magnetic field and across the direction of travel of the ions emitted by the ion source. Among other potential advantages, ion generation has a narrower energy distribution, which produces sharper peaks in the mass spectrum, thereby providing high resolution. Other potential advantages are taught in this document.

[0026] Reference will first be made to Figures 1 - 3 describe a gas analyzer system, wherein Figure 1 is a top view of the gas analyzer system 100, showing the internal components within a cross-section of the housing 180. Figure 2 is a perspective view of the exterior of the housing 180, showing the magnet assembly 264; and Figure 3 is a perspective side view of the internal components of the system and the side wall 382.

[0027] In Figure 1 , the gas analyzer system 100 includes an ion source 104 that is constructed to establish a source electric field in the ion region 110 of the ion source 104. For example, in Figure 1 , the source electric field can be directed from right to left between the source pusher electrode 108 and the anode electrode 106. The ion region 110 receives gas from a monitored chamber such that ions of the gas are formed in the ion source 104. The source aperture 114 is positioned to emit a portion of the gas ions from the ion source 104 and can be an aperture formed in a portion of the anode electrode 106. The ions are accelerated by the source electric field in the direction toward the source aperture 114. The magnet assembly 264 (see Figure 2 ) is positioned to define a magnetic field to angularly displace ions emitted from the source aperture 114 ( Figure 1 ) based on the mass-to-charge ratio of the ions, for example, by defining a magnetic field across the flight region of the emitted ions, as shown at 860 in Figure 8 below. As will be shown relative to Figure 3 and Figure 4 , after passing through Figure 1The ion source 104 creates an electron beam 326. The electron beam collides with gas molecules to form ions of the gas in the ion source 104. In addition to the source pusher electrode 108, the anode electrode 106 may extend to form a wall substantially surrounding the ion source 104. In another embodiment, the ion source 104 may be made of wire mesh material, so that its passage to the gas. In this case, the solid wall of the ion source 104 is replaced by a perforated wire mesh or a sintered wire mesh. Figure 1 The source aperture 114 of may, for example, have a width of about 0.005 inches, although it should be understood that other sizes may be used.

[0028] The vacuum port 148 allows gas from the monitored chamber to enter the gas analyzer system from the monitored chamber, so that the gas travels in a direction opposite to the ion beam, that is, the gas travels in a direction from the detector 116 towards the source aperture 114. At the ion source 104, the gas enters the ion source 104 (e.g., through an opening in the top of the ion source 104, or in some cases through the open or perforated side of the ion source 104), and then ionizes inside the ion source 104 to form an ion beam, which is emitted in the opposite direction, that is, the ion beam travels from the source aperture 114 towards the detector 116.

[0029] Figure 2 is Figure 1 A perspective view of the exterior of the housing of the gas analyzer system, showing a magnet assembly 264 used with the gas analyzer system according to an embodiment of the present invention. The magnet assembly 264 may include a monolithic magnet that extends above the ion source and extends in a direction longitudinally extending from the source aperture towards the detector. In Figure 2 the example of, two monolithic magnets (top and bottom) are shown, sandwiching the region of the ion flight path between the source aperture and the detector, which helps to establish a uniform magnetic field in the flight path region. The magnetic field provided by the magnet assembly 264 may, for example, be 1 kGauss throughout, and may provide sufficient separation of the ion components to ensure separation of water from other residual gases. By adding another magnet 266, or a magnetic yoke, or both, above the flight path, another magnetic intensity in the flight path can be obtained for additional mass separation. In Figures 1 - 3 the hot cathode ion source embodiment, in addition to the ion flight region between the source aperture and the detector, the magnet assembly 264 may also extend above the ion source 104 (see Figure 1 ) but is not necessary. The advantage of extending the magnet assembly 264 above the ion source 104 is that in the electron beam 326 (see Figure 3)Adding a magnetic field above increases the circular orbits of the electrons, which increases the electron trajectory length. However, in some embodiments of the hot cathode ion source, the magnet assembly 264 extends only above the ion flight region between the source aperture and the detector. In contrast, in embodiments of the cold cathode ion source, as shown in Figure 11 , a magnet assembly 264 is required to define a crossed-field configuration across the electric field within the cold cathode ion source and may extend above the ion flight region between the source aperture and the detector to facilitate mass separation of the ions. Also shown in Figure 2 are the electrical feedthroughs 240 (see also Figure 5 and 6 ), which all extend through a sidewall.

[0030] The positioning detector 116 (see Figure 1 ) is positioned to detect the displaced ion component of the emitted portion of the ions. The detector 116 can for example include a detector aperture 120, which can have a width of about 0.010 inches, although it will be understood that other sizes can be used. The detector 116 can also include a Faraday collector 122. The detector aperture 120 can be biased with a voltage such that it acts as an energy filter for the ions. As discussed, for example, for the energy filter grids 124a / 124b below and with the bias of the detector shield 1198 (discussed in Figure 11 ), other types of energy filters can be used.

[0031] The ion beam deflector 118 is positioned between the source aperture 114 and the detector 116. The ion beam deflector 118 defines a deflecting electric field across the magnetic field (see the direction 860 in Figure 8 ) and across the direction of travel of the ions emitted from the source aperture (i.e., across the direction of travel from the source aperture 114 to the detector aperture 120 in Figure 1 ). For example, in Figure 1 , the deflector 118 can define a deflecting electric field in the direction from the top to the bottom of Figure 1 . The ion current measuring circuitry (not shown in Figure 1 , see 970 in Figure 9 ) is electrically connected to measure the current generated by the displaced ion component received at the detector 116.

[0032] Additionally, Figure 1The system includes energy filters positioned in the ion beam path, such as energy filter grids 124a and 124b. Energy filter grid 124a is an entrance grid that is positioned between the source aperture 114 and the entrance where the ion beam enters the ion beam deflector 118. Energy filter grid 124b is an exit grid that is positioned between the exit of the ion beam from the ion beam deflector 118 and the detector aperture 120. It will be understood that one or both of the entrance grid 124a and the exit grid 124b may be used.

[0033] Figure 3 is a side perspective view of the inner components of the system and the side wall 382. Here, it should be noted that in some embodiments, for ease of assembly, the inner components of the system can be conveniently mounted to the side wall 382, while the electrical feedthroughs (see Figure 2 , 5 and 240 in 6) all extend through one of the side walls. Additionally, it should be noted that the side wall 382 (see Figures 3 - 7 ) and the bottom plate 480 (see, for example, Figure 4 ) can form part of the housing 180 (see Figure 1 and 2 ).

[0034] Figure 4 is a perspective view of the ion source 104 of a Figure 1 gas analyzer system according to an embodiment of the present invention. The ion source 104 can be a hot cathode ion source, which can include a hot filament 428 (or other hot cathode ion source) and an electron collector 430, and this electron collector 430 is constructed to establish an electron beam 326 passing through the ion source 104 between the hot filament 428 and the electron collector 430. The filament deflector 432 focuses the electron beam 326. Due to the magnetic field across the ion source, the electrons in the electron beam 326 precess in a circular trajectory. An exit hole 434 is formed in the insulator 436, and this insulator 436 forms the bottom of the ion source 104. The hot filament 428 and the electron collector 430 can be constructed to establish the electron beam 326 in a direction parallel to the source aperture 114, where the source aperture 114 extends in a direction parallel to the electron beam; for example, in Figure 4 , both the electron beam 326 and the source aperture 114 are vertically aligned in Figure 4 . The most efficient electron-ion design directs the electrons parallel to the magnetic field and the source aperture. The ions that can reach the source aperture should originate within a narrow potential energy range, that is, in the flat equipotential region of the ion source, and modeling can be used to find it.

[0035] As Figure 4 shown, the entrance grid 124a can include conductive filaments 438 oriented substantially perpendicular to the elongated aperture of the source aperture 114 - that is, in Figure 4Horizontally herein, the source aperture 114 is oriented upright - without a conductive filament (or substantially without a filament) being oriented in an elongated aperture that is substantially parallel to the source aperture 114 - that is, in Figure 4 there is no filament oriented upright. In this way, no grid lines will interfere with the path between the source aperture and the detector aperture, such as where a vertically oriented ribbon beam is scanned horizontally across the grid, which would be encountered if vertical filaments were used in the conductive grid. For example, this configuration can provide a doubling of signal sensitivity without affecting resolution or peak position. The exit grid (see Figure 1 124b in Figure 4 ) can use conductive filaments 438 of the same configuration (

[0036] [[ID=**63]]Figure 5 ), which are oriented substantially perpendicular to the elongated aperture of the source aperture 114. Figure 1 is a side view of the inner components and side walls of the gas analyzer system of

[0037] Figure 6 . Several electrical feedthroughs 240 (which are not listed separately) allow the transmission of electrical signals and power in and out of the housing of the gas analyzer system. The filament supply 542 and the filament return 544 transmit power in and out of the hot filament. Figure 1 is a top view of the inner components and side walls of the gas analyzer system of Figure 6 in accordance with an embodiment of the present invention. This view shows the electrical feedthroughs 240 extending from the outside of the housing of the gas analyzer system and into the interior of the housing. Also shown in this top view are the source pusher electrode 108, the filament supply 542, and the filament return 544, each of which has its own electrical feedthrough, and the filament deflector 432. Figure 1 ) and also shown in is the deflection plate 646a, which is one of a pair of parallel plates forming the ion beam deflector 118 ( Figure 6 ), and the other parallel plate is not shown herein (see Figure 7 746b in Figure 6 ). As shown in Figure 6 , the entrance grid 124a and the exit grid 124b are respectively positioned at the entrance and exit of the ion beam into and out of the ion beam deflector, that is, herein between the electrode deflection plate 646a and its corresponding parallel plate (see Figure 7 746b in Figure 6 , which is not shown in

[0038] Figure 7FIG. 0 is a schematic diagram showing the eccentric operation of the deflection plates 646a / 746b according to an embodiment of the present invention. Here, the positioning source aperture 114 is arranged to emit an ion beam 758 from the ion source 104 to enter the ion beam deflector 118 on a side closer to the ion beam deflector 118 than the geometric center 750 of the ion beam deflector 118. This configuration provides several potential benefits. By reducing the distance to the deflection plate to which the voltage is applied, a lower voltage is required on the deflection plate, thereby saving power costs, reducing the ratings required for the electrical feedthroughs, and increasing the reliability of the components. In addition, the equipotential lines are flatter and closer to the deflection plate, and thus the ion beam is less distorted along its flight path.

[0039] Figure 8 FIG. 4 is a schematic diagram of a gas analyzer system according to an embodiment of the present invention, showing the electrical components and the ion beam path through the magnetic field. This system includes a source pusher electrode 108 biased at a voltage VPE = Va + VPUSH, where VPE is the voltage of the source pusher electrode 108, Va is the voltage of the anode electrode 106, and VPUSH is the bias voltage of the source pusher electrode 108, which can be, for example, up to 200 V. An electron beam 326 travels between the hot filament 428 and the electron collector 430. The filament heater voltage 852 is set, for example, to 2 V at a current of 2 A. The filament bias voltage 854, VFB is, for example, between 0 and 100 V. The anode bias voltage 856, Va is, for example, between 200 V and 500 V. The ion beam 758 is emitted through the entrance grid 124a and travels between the deflection plates 646a / 746b. The magnetic field direction 860 is shown, and the magnetic field can have a magnitude of, for example, about 1 kGauss. (Note that for ease of illustration, Figure 8 the orientation of the electron beam 326 in FIG. 4 is shown upright on the page, while in other embodiments shown herein, the electron beam 326 will be oriented out of the page to be parallel to the elongated source aperture as shown elsewhere herein). One deflection plate 646a, i.e., the pusher deflection plate, is biased at a voltage 862, V(t), which in this example is a sawtooth voltage that peaks at about 1000 V, while the other deflection plate 746b is at ground voltage. The exit grid 124b is biased, for example, at VF = 0 - 500 V. The detector aperture 120 is biased at ground voltage. In another example, energy filtering can be produced by holding the exit grid 124b at ground and instead biasing the detector aperture 120. The Faraday collector 122 receives the detected portion of the ion beam 758 and generates a detected ion current IPP,G, which can be used, for example, to measure the partial pressure of the ion component detected at the detector aperture 120.

[0040] In Figure 8In an embodiment, a high energy source is designed to generate ions within an ion volume biased at a high voltage. A source pusher electrode 108 forces the ions out through a thin aperture of the source aperture into the magnetic section. The ions leave this energy source and acquire a high kinetic energy before flying through the mass separator, which remains at ground potential when the deflection plates 646a / 746b are closed. The bias voltage of this energy source can be adjusted to control the ion energy passing through the magnetic section. The advantage of this design is that the entire flight path remains at ground potential and only this energy source needs to be floated. Depending on the voltage bias of the ion region, it is usually possible to bring the filament close to ground potential and have electrons acquire high energy when entering this energy source.

[0041] In Figure 8 , ions are generated inside the anode within the ion region defined by the electron beam 326. Since the potential is well defined within the ion band, the ion energy distribution is very narrow. To obtain the most efficient ionization, the electron beam 326 can be parallel to the magnetic field 860 (again note that, for ease of illustration, Figure 8 the energy source in Figure 1 is shown in the plane of the page, but can be in a direction parallel to the magnetic field 860), so that the electrons precess in a circular trajectory and have a longer ion trajectory. The ions formed inside the anode 106 are pushed towards the source aperture by the source pusher electrode 108. The electrons are accelerated as they travel towards the anode 106 and reach an energy equal to the voltage difference between the anode 106 and the filament bias voltage 854. The electron beam 326 traverses the ion region in a band located near the anode aperture 114 (see Figure 1 ). This causes the ions to form in an equipotential region providing a narrow energy distribution.

[0042] Figure 9 is a schematic perspective view of a gas analyzer system according to an embodiment of the present invention, which uses an ion beam deflector 118 to deflect the ion component to be detected by the detector. The ion beam deflector 118, such as a pair of parallel plates 646a and 746b, or a pair of curved plates (see Figure 12 the 646a and 746b in Figure 2), a magnetic field in the ion flight region between the source aperture 114 and the detector 116 produces a mass-dependent deflection that causes the ions to become separate ion components 968b-d. Lighter ions are deflected more than heavier ions. For example, the displaced ion component 968b is made up of helium ions, 968c is made up of water ions, and 968d is made up of residual gases such as nitrogen and oxygen. This increased deflection of the ion components using an additional magnet can, for example, allow the water ions to be separated from the remaining residual gas ions 968d. The detector 116 includes a metallized Faraday collector 122 that produces an ion current proportional to the ion flux arriving at the detector 116 through the detector aperture 120. This ion current is the partial pressure current IPP of the ion component 968d arriving at the detector. The ion current measurement circuitry 970 is used to measure the partial pressure current. This partial pressure can be used to provide an indication of the partial pressure of the gas from the monitored chamber, specifically the mass-separated ion component 968d arriving at the detector. Additionally, the total current measurement circuitry 901 can be electrically connected to measure the total ion current of the ion source. For example, the total current measurement circuitry 901 can measure a total current proportional to the total ion current flowing out of the ion source, which can be used to determine the total pressure of the gas from the monitored chamber. For example, as Figure 9 shown, the total current measurement circuitry 901 can measure the total current flowing into the ion source (here, into the hot filament of the heat source), but the total current measurement circuitry 901 can alternatively measure the total current in another way, such as by measuring the current flowing through the anode 106. Based on the partial pressure current and the total pressure current, a total pressure display electrically connected to the total current measurement circuitry 901 can provide an indication (e.g., a visual indication) of the total pressure of the gas from the monitored chamber; and a partial pressure display electrically connected to the ion current measurement circuitry 970 can provide an indication (e.g., a visual indication) of the partial pressure of the gas from the monitored chamber.

[0043] Additionally, in Figure 9 the embodiment, the ion beam deflector 118 is used to steer the ion components 968b-d into the detector aperture 120. Conversely, the magnetic field bends the trajectories of the ion components downward (refer to Figure 9 the top view), and the electric field between the deflection plates 646a and 746b electrostatically steers the ion component trajectories upward, refer to Figure 9 , adopting a "pusher" configuration where the deflection plate 646a is positively biased relative to the grounded deflection plate 746b. In Figure 9Among them, for example, the voltage difference between the deflection plates 646a and 746b is set such that the residual gas component 968d is detected. When both the deflection plates 646a and 746b are at ground, based on the angle of the source aperture and the deflection amount of the ion component from the magnetic field, all ions will miss the detector aperture 120. However, here, by changing the voltage of one of the deflection plates relative to the other deflection plate 746b (grounded in this example), here it is the voltage of the pusher deflection plate 646a (increased in the positive direction here), the ion components 968b-d are turned upward (or downward depending on the voltage change), and different ion components are allowed to pass through the detector aperture 120. In Figure 9 Among them, the pusher deflection plate 646a is set to a voltage such that the residual gas ion component 968d reaches the detector aperture 120. As the voltage on the deflection plate 646a further increases, the water ion component 968c or the helium ion component 968b will reach the detector aperture 120 and generate a signal. Thus, the deflector 118 allows the ion components to be turned so that most ion component species can be successively brought to the detector 116. In Figure 9 In the example of, the deflection plate 646a is a pusher deflection plate that is swept with a positive voltage relative to the grounded deflection plate 746b. Other configurations can be used; for example, one deflection plate can be at a negative voltage relative to another grounded deflection plate; or the two deflection plates can be at different voltage biases. In Figure 9 In the example of, for the pusher deflection plate, based on the deflection caused by the magnetic field, the ion components can, for example, come out of the source aperture 114 and fly towards the pusher deflection plate 646a. In this example, with the deflection plates 646a and 746b closed, no ion components reach the detector aperture 120. When the voltage of the pusher deflection plate 646a is swept with a positive voltage, the ion components start to be pushed towards the detector aperture 120. First, the heavier ions enter the detector aperture 120, and the lighter ion components require a higher voltage to sweep the ion components so that the lighter ion components reach the detector aperture 120.

[0044] Scanning the voltage on one or two deflection plates, for example, by scanning the voltage on the pusher deflection plate 646a, and plotting the relationship between the ion component signal (such as partial pressure current) and the voltage on the deflection plate allows the generation of a real-time mass spectrum. For example, a graphical display can be created on a visual display device, showing the detected partial pressure current (in volts) provided by a picoammeter current-to-voltage converter on the vertical axis, and the time (in seconds) linearly related to the voltage on the deflection plate on the horizontal axis (since the deflection voltage is swept in a sawtooth waveform). Additionally, automatic zero baseline subtraction can be performed.

[0045] In Figure 9In [the context], the deflector power supply 972 is electrically connected to the ion beam deflector 646a to establish a deflection electric field between the deflection plates 646a and 746b of the ion beam deflector. The deflector power supply 972 can be electrically connected to (i) a ground voltage relative to the second deflection plate 746b of the ion beam deflector to provide a positive deflector bias voltage to the first deflection plate 646a of the ion beam deflector, or (ii) a ground voltage relative to the second deflection plate 746b to provide a negative deflector bias voltage to the first deflection plate 646a, or (iii) provide a first deflector bias voltage to the first deflection plate 646a and provide a second deflection plate to the second deflector bias voltage 746b.

[0046] In Figure 9 [the context], the deflector control circuit 974 can be configured to provide a deflector control signal to the deflector power supply 972. The control circuit 974 can be configured to control the voltage of the deflector power supply 972 to cause the ion beam deflector 118 to direct displaced ion components having different energies and a common ion component mass to be focused through the detector aperture of the detector, as shown in the following Figure 10 [the context]. Additionally, the deflector control circuit 974 can be configured to vary the voltage of the deflector power supply 972 to cause the ion beam deflector to vary the deflection of the displaced ion components of the emission portion of the ions. The voltage of the deflector power supply 972 can be varied based on (i) a triangular sawtooth variation of the voltage over time (as shown in Figure 8 [the context]) or (ii) a voltage waveform that controls the peak width and time position of the displaced ion components relative to other ion components. The deflector control circuit 974 can be configured to scan the voltage of the deflector power supply 972 to cause the ion beam deflector to deflect a plurality of ion components 968b - d to be successively detected by the detector when scanning the voltage of the deflector power supply 972; and can be configured to scan the voltage of the deflector power supply 972 to allow the mass spectrum of the plurality of ion components to be detected, as described above.

[0047] In Figure 9 Another version of the embodiment of [the context], the ion beam deflector 118 can be configured to align the ion beam 758 of the emission portion of the ions on the detector (see Figure 7 ). For example, the current ion beam alignment in a helium sensor depends on the mechanical tuning of the electron beam at the hot cathode ion source, which can be a slow and tedious process. However, by using the ion beam deflector 118 as described herein to realign the ion beam, mechanical adjustment is not required.

[0048] Additionally, by making measurements at the top and sides of the spectral peaks, the ion beam deflector 118 can be used to determine the spectral baseline offset. This can also provide an advantage over conventional helium leak detectors.

[0049] Figure 10FIG. 0 is a schematic view showing energy focusing using a deflector plate according to an embodiment of the present invention. In energy focusing, ion components having different energies and a common ion component mass are focused through a detector aperture 120 of a detector. For example, low-energy ions 1076 and high-energy ions 1078 of a common ion component, such as low-energy water ions and high-energy water ions, can be focused through the detector aperture 120. In another example, low-energy residual gas ions and high-energy residual gas ions can be focused through the detector aperture 120. To effect this energy focusing, a deflector control circuit 974 ( Figure 9 ) is constructed to control the voltage of a deflector power supply 972 ( Figure 9 ) to cause an ion beam deflector to direct ion components 1076 and 1078 having different energies and a common ion component mass to be focused through the detector aperture 120. For each ion component mass, the deflector power supply has a specific voltage that can provide energy focusing. The deflector voltage for directing the ion beam of the mass of interest such that the ion beam reaches the detector is also the same as the voltage for the energy focusing achieved for the mass of interest. In a hot or cold cathode ion source embodiment, this can be effected by laterally displacing the detector aperture or the source aperture (or both). Additionally, in a cold cathode ion source embodiment, the source can be rotated.

[0050] Figure 12 FIG. 8 is a schematic view of an ion beam deflector including a pair of curved plates according to an embodiment of the present invention. Here, plates 646a and 746b are curved, which is different from the parallel plates 646a and 746b shown elsewhere herein. The operation can be generally similar to that of the parallel plates described herein. It will be understood that many different shapes and configurations can be used for the ion beam deflector and plates 646a and 746b, and the lengths and curvatures of the curved plates 646a and 746b can be optimized.

[0051] In another embodiment, the ion source can include a cold cathode ion source. Figure 11 FIG. 13 is a schematic perspective view of a gas analyzer according to an embodiment of the present invention that uses an inverted magnetron cold cathode discharge electrode configuration and an ion beam deflector 118 to deflect ion components to be detected by a detector. The ion beam deflector 118, such as a pair of parallel plates 646a and 746b, or a pair of curved plates (similar to those shown in Figure 12 ) is positioned between a source aperture 114 and a detector 116. As in the hot cathode ion source embodiment, the ion beam deflector 118 can be used to deflect ion components and effect energy focusing.

[0052] As in the case of the hot cathode ion source embodiment, the displaced ion component 968 is separated into different ion components which diverge more and more from each other as they further travel through the source aperture 114. In an inverted magnetron cold cathode discharge configuration, the cathode electrode assembly 1184 surrounds the anode electrode 1186. The axial magnetic field (created using the magnet assembly 264, not shown in Figure 11 ), is centered on the anode electrode 1186 and a radial electric field is established by applying a high voltage potential Vanode to the anode electrode 1186. In a crossed field configuration of the electric and magnetic fields (indicated by the direction 1188 of the electric field and the direction 1190 of the magnetic field), a pure electron plasma 1192 is established around the anode electrode 1186. Gas molecules entering the pure electron plasma 1192 are ionized by the precessing electrons and form ions which are immediately accelerated towards the cathode electrode assembly 1184 by the radial electric field. The magnetic field inside this source is high enough (e.g., 1 kGauss) to cause the electrons to precess in a compact circular trajectory, but has less effect on the heavier ions whose trajectories experience a slightly mass-dependent magnetic deflection as they fly towards the cathode electrode assembly 1184. The source aperture 114, e.g., a straight slit in the cathode wall, allows a small beam of the ion component 968 to leave this source. Using additional magnets (see Figure 2 264 in Figure 11 ), not shown in Figure 11 ), the magnetic field is extended to the flight region between the source aperture 114 and the detector 116, thereby increasing the mass-dependent deflection of the ions into separate ion components 968b-d. The lighter ions are deflected more than the heavier ions. For example, the displaced ion component 968b is made of helium ions, 968c is made of water ions, and 968d is made of residual gases such as nitrogen and oxygen. This increased deflection of the ion components using additional magnets can, for example, allow the water ions to be separated from the rest of the residual gas ions 968d. The detector 116 includes a metal Faraday collector half cylinder 122 which generates an ion current proportional to the ion flux arriving at the detector 116 through the detector aperture 1194. This ion current is the partial pressure current IPP of the ion component 968d arriving at the detector. Also shown in Figure 11 is the total pressure current IT.

[0053] In addition, in Figure 11In an embodiment, an ion beam deflector 118 is used to steer ion components 968b-d into a detector aperture 1194. Also, a detector shroud electrical connector 1196 electrically connects between a detector shroud 1198 and a voltage source 1199 that applies a detector shroud bias voltage to the detector shroud 1198, such that the detector shroud 1198 is thereby a high-pass ion energy filter. Using the high-pass ion energy filter, only ions having an energy higher than the detector shroud bias voltage can cross the plane of the detector aperture 1194, and the remaining ions are turned back. Increasing the detector shroud bias voltage narrows the energy distribution or spread of the ions that can reach the detector 116 during a deflector voltage scan, resulting in a narrower mass peak as the voltage increases. Although Figure 1 an embodiment uses an energy filter grid 124a / 124b, other types of energy filters can be used. For example, in Figure 11 an embodiment, the detector shroud 1198 has a detector shroud bias voltage applied thereto (and the detector shroud is isolated from ground), such that the detector shroud 1198 is a high-pass ion energy filter. In Figure 11 Note: The text seems to be a list of figure references. The translation is done as per the requirements. If there are any specific context or further instructions related to these figure references, it might help in providing a more meaningful interpretation. Also, in the original text, there is a tag which is likely a misspelling in the original as it's not in the sequence pattern of the others. It's translated as "Figure 5" as it's the most likely intended meaning based on the sequence. If this is incorrect, more information would be needed to correct it accurately. a cold cathode ion source embodiment, the energy of the ions depends on the pressure of the gas: generally, as the pressure increases over the useful pressure range of the analyzer, the energy of the ions decreases, and the energy spread of the ions decreases, this pressure range can be, for example, from 10-10 to 10-3 Torr. In contrast, with the hot cathode ion source taught herein, the energy spread of the ions is very small, and the energy of the ions does not change with pressure.

[0054] As used herein, a hot cathode ion source can include any hot cathode ion source, including those based on incandescent filaments and ion sources that use thermionic emission. Additionally, other ion sources can be used, including cold cathode ion emitters, such as electron generator arrays and field emitters. Hot cathode ion sources are generally more complex than cold cathode ion sources. However, hot cathode ion sources provide a smaller energy distribution for the ions, which can result in improved resolution.

[0055] The systems taught herein can be used in many different possible scenarios, including, for example, as a helium sensor in a helium leak detector; used in a mass spectrometer; used in a sector magnetic field; and for most gas detections.

[0056] Many different possible advantages can be achieved using the embodiments taught herein. Ions can be produced with a narrower energy distribution, which translates into sharper peaks in a mass spectrum. This provides high resolution. Additionally, the energy of the ions can be pressure-independent. Since a complex non-linear look-up table is not required, the ion signal is linear with pressure, making quantification easier. The ion energy does not change with pressure, meaning that relative pressure is not required to adjust the peak position and filter voltage, or only a small adjustment is needed. A smaller-sized helium sensor can be provided for a helium leak detector, which provides an opportunity to reduce the size of current mass spectrometers. Compared with a standard helium sensor in a helium leak detector, the ability to scan eliminates the need to use a 180-degree bend, making the detector more compact. Additionally, the filament position generally does not need to be adjusted as often as during helium leak detector commissioning. Instead, with the help of deflection plates, any change in the ion beam position can be compensated for by adjusting the deflection plate voltage.

[0057] Furthermore, the high-energy source taught herein can be very effective, where the components of the system work well together. The same anode potential that excites the ions also attracts electrons to the ion region. The fact that the flight path is at ground reduces the chance of arcing or electric shock. The voltage required is very small and is easy to implement in electronics. Starting from a low potential can ensure a small energy distribution for the ions, resulting in good spectral resolution.

[0058] The teachings of all patents, published applications, and references cited herein are hereby incorporated by reference in their entirety.

[0059] Although the exemplary embodiments have been shown and described specifically, those skilled in the art will understand that many changes may be made in form and detail without departing from the scope of the embodiments covered by the appended claims.

Claims

1. A gas analyzer system, the system comprising: An ion source configured to establish a source electric field in an ion region of the ion source, the ion region receiving a gas from a monitoring chamber such that ions of the gas are formed in the ion source; A source aperture positioned to emit a portion of the gas ions out of the ion source, the ions being accelerated in a direction toward the source aperture by the source electric field; A magnet assembly positioned to define a magnetic field to angularly displace an emitted portion of the ions based on the mass-to-charge ratio of the gas ions; A detector positioned to detect a displaced ion component of the emitted portion of the ions; An ion beam deflector positioned between the source aperture and the detector, the ion beam deflector defining a deflection electric field across the magnetic field and across the direction of travel of the emitted portion of the ions; An ion current measurement circuitry electrically connected to measure a current generated by the detector receiving the displaced ion component; The ion beam deflector is configured to direct displaced ion components having different energies and a common ion component mass to be focused through a detector aperture of the detector, and the source aperture is positioned to emit a portion of the ions of the gas from the ion source to enter the ion beam deflector closer to one side of the ion beam deflector than to the geometric center of the ion beam deflector.

2. The gas analyzer system of claim 1, wherein the ion source comprises a cold cathode ion source.

3. The gas analyzer system of claim 1, wherein the ion source comprises a hot cathode ion source.

4. The gas analyzer system of claim 3, wherein the hot cathode ion source comprises a hot filament and an electron collector, the electron collector configured to establish an electron beam through the ion source between the hot filament and the electron collector.

5. The gas analyzer system of claim 4, wherein the hot filament and the electron collector are configured to establish the electron beam in a direction parallel to the source aperture, and the source aperture comprises an aperture elongated in a direction parallel to the electron beam.

6. The gas analyzer system of claim 1, further comprising an energy filter.

7. The gas analyzer system of claim 6, wherein the source aperture comprises an elongated aperture, and wherein the energy filter comprises an energy filter grid positioned in an ion beam path of the emitted portion of the ions, the energy filter grid comprising conductive filaments oriented substantially perpendicular to the elongated aperture of the source aperture and substantially not comprising conductive filaments oriented substantially parallel to the elongated aperture of the source aperture.

8. The gas analyzer system of claim 6, wherein the energy filter comprises an entrance grid positioned between the source aperture and an entrance of the ion beam of the emitted portion of the ions into the ion beam deflector.

9. The gas analyzer system of claim 6, wherein the energy filter comprises an exit grid positioned between an exit of the ion beam of the emitted portion of the ions exiting the ion beam deflector and the detector aperture.

10. The gas analyzer system of claim 1, wherein the ion beam deflector is configured to align the ion beam of the emitted portion of the ions onto the detector.

11. The gas analyzer system of claim 1, wherein the ion beam deflector comprises a pair of parallel plates.

12. The gas analyzer system of claim 1, wherein the ion beam deflector comprises a pair of curved plates.

13. The gas analyzer system of claim 1, further comprising a deflector power supply electrically connected to the ion beam deflector to establish the deflection electric field between a pair of deflection plates of the ion beam deflector.

14. The gas analyzer system of claim 13, wherein the deflector power supply is electrically connected to (i) provide a positive deflector bias voltage to the first deflection plate of the ion beam deflector with respect to the ground voltage of the second deflection plate of the ion beam deflector, or (ii) provide a negative deflector bias voltage to the first deflection plate with respect to the ground voltage of the second deflection plate, or (iii) provide a first deflector bias voltage to the first deflection plate and a second deflector bias voltage to the second deflection plate.

15. The gas analyzer system of claim 13, further comprising a deflector control circuit configured to supply a deflector control signal to the deflector power supply.

16. The gas analyzer system of claim 15, wherein the deflector control circuit is configured to control the voltage of the deflector power supply to cause the ion beam deflector to direct displaced ion components having different energies and a common ion component mass to be focused through a detector aperture of the detector.

17. The gas analyzer system of claim 15, wherein the deflector control circuit is configured to vary the voltage of the deflector power supply to cause the ion beam deflector to vary the deflection of the displaced ion components of the emission portion of the ions.

18. The gas analyzer system of claim 17, wherein the deflector control circuit is configured to vary the voltage of the deflector power supply to control the peak width and time position of the displaced ion components relative to other ion components based on (i) a triangular sawtooth variation of the voltage over time, or (ii) a voltage waveform.

19. The gas analyzer system of claim 15, wherein the deflector control circuit is configured to scan the voltage of the deflector power supply to cause the ion beam deflector to continuously deflect a plurality of ion components detected by the detector when scanning the voltage of the deflector power supply. [[ID=⑧]]20. The gas analyzer system of claim 19, wherein the deflector control circuit is configured to scan the voltage of the deflector power supply to permit detection of a mass spectrum of the plurality of ion components.

21. The gas analyzer system of claim 1, further comprising a total current measuring circuit device electrically connected to measure the total ion current of the ion source.

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