Multi-section, angled linear accelerator, x-ray system, and method of operating the same

Abstract

Linear accelerators with accelerator sections, X-ray source including the same, and methods of operating a linear accelerator are disclosed. A linear accelerator can include a first section having a first acceleration axis, a second accelerator having a second acceleration axis oblique to the first acceleration axis, and a radiofrequency source coupled to the first acceleration section and second acceleration section.

Description

Attorney Docket No. P323376.WO.01_504935-873Client Docket No. 2024-032-W01MULTI-SECTION, ANGLED LINEAR ACCELERATOR, X-RAY SYSTEM,AND METHOD OF OPERATING THE SAME CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to U.S. Patent Application No. 63 / 760,440, filed 19 February 2025, the entire disclosure of which is hereby incorporated by reference.FIELD

[0002] The described embodiments relate generally to linear accelerators, and more particularly, to linear accelerators including multiple acceleration sections angled relative to one another.BACKGROUND

[0003] Linear accelerators (also referred to as “LINACs”) can be used to accelerate electrons, ions, or other charged particles by subjecting them to oscillating electric potentials in a series of chambers or cavities. LINACs are widely used for a variety of tasks in a broad range of applications, including radiotherapy, non-destructive testing, security inspection, electron beam processing (e.g., sterilization, polymer curing, and the like), and the like. In an X-ray application, a LINAC can generate an accelerated electron beam, which can strike a conversion target at an end of an accelerating channel to produce X-rays.LINACs can be used for many other applications, including, but not limited to electronic chip manufacturing and the like. The present disclosure focuses on electron beam LINACs; however, the teachings of the present disclosure can be used with LINACs for accelerating any charged particles for any applications.SUMMARY

[0004] One aspect of the present disclosure relates to a linear accelerator, the linear accelerator including a first accelerator section having a first acceleration axis, a second accelerator section having a second acceleration axis oblique to the first acceleration axis, and a radiofrequency (RF) source coupled to the first accelerator section and the second accelerator section.

[0005] In one or all examples, the first accelerator section can include a first electron source, and the second accelerator section can include a second electron source.14936-5873-8024'1Attorney Docket No. P323376.WO.01_504935-873Client Docket No. 2024-032-W01

[0006] In one or all examples, the first acceleration axis and the second acceleration access can be directed toward a target surface.

[0007] In one or all examples, the first accelerator section can be configured to operate at a first energy greater than a second energy at which the second accelerator section can be configured to operate.

[0008] In one or all examples, the first acceleration axis and the second acceleration axis can be directed toward a target surface, the first acceleration axis can be orthogonal to the target surface, and the second acceleration axis can be oblique to the target surface.

[0009] In one or all examples, the first accelerator section can have a first length greater than a second length of the second accelerator section.

[0010] In one or all examples, a first distance between the first accelerator section and a target surface can be greater than a second distance between the second accelerator section and the target surface.

[0011] In one or all examples, the RF source can be coupled to the first accelerator section, and the RF source can be coupled to the second accelerator section through the first accelerator section.

[0012] Another aspect of the present disclosure relates to an X-ray source, the X-ray source including a first linear accelerator including a first electron gun, a second linear accelerator including a second electron gun, and a side cavity coupling the first linear accelerator to the second linear accelerator. The first linear accelerator and the second linear accelerator can be configured to direct charged particles toward a target surface to produce X-rays.

[0013] In one or all examples, the first linear accelerator and the second linear accelerator can be coupled to a magnetron.

[0014] In one or all examples, the first linear accelerator can be configured to generate a first electron beam having a first electron beam energy, and the second linear accelerator can be configured to generate a second electron beam having a second electron beam energy less than the first electron beam energy.

[0015] In one or all examples, the first linear accelerator can be configured to direct the first electron beam towards the target surface at an angle normal to the target surface, and the second linear accelerator can be configured to direct the second electron beam towards the target surface at an angle oblique to the first electron beam and the target surface.24936-5873-8024'1Attorney Docket No. P323376.WO.01_504935-873Client Docket No. 2024-032-W01

[0016] In one or all examples, the first linear accelerator can have a first length, and the second linear accelerator can have a second length less than the first length.

[0017] In yet another aspect of the present disclosure, a method of operating a linear accelerator includes driving a first high-voltage pulse to generate a first electron beam having a first electron beam energy, driving a second high-voltage pulse to generate a second electron beam having a second electron beam energy different from the first electron beam energy, and supplying a constant RF power while driving the first high-voltage pulse and the second high-voltage pulse.

[0018] In one or all examples, the first high-voltage pulse and the second high-voltage pulse can be driven by a high-voltage driver.

[0019] In one or all examples, the first high-voltage pulse can be driven by a first griddriving circuit, and the second high-voltage pulse can be driven by a second grid-driving circuit.

[0020] In one or all examples, the first high-voltage pulse can be driven by a first high-voltage driver, and the second high-voltage pulse can be driven by a second high-voltage driver.

[0021] In one or all examples, the first high-voltage pulse can be driven to a first electron source and the first electron beam is generated by a first accelerator subsection, the second high-voltage pulse can be driven to a second electron source and the second electron beam is generated by a second accelerator subsection, and the constant RF power can be supplied by a magnetron coupled to the first accelerator subsection and the second accelerator subsection.

[0022] In one or all examples, the first electron beam and the second electron beam can be emitted towards a target at different angles.

[0023] In one or all examples, the first electron beam can be driven towards a target at an angle orthogonal to the target, and the second electron beam can be driven towards the target at an angle oblique to the target.34936-5873-8024'1Attorney Docket No. P323376.WO.01_504935-873Client Docket No. 2024-032-W01BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The disclosure will be readily understood by the following detailed description in conjunction with the accompanying drawings, wherein like reference numerals designate like structural elements, and in which:

[0025] FIG. 1 is a cross-sectional view of an X-ray source.

[0026] FIG. 2 is a cross-sectional view of an X-ray source.

[0027] FIG. 3 is a block diagram of an X-ray source.

[0028] FIG. 4 is a block diagram of an X-ray source.

[0029] FIG. 5 is a flowchart of a method of operating a linear accelerator.44936-5873-8024'1Attorney Docket No. P323376.WO.01_504935-873Client Docket No. 2024-032-W01DETAILED DESCRIPTION

[0030] Reference will now be made in detail to representative embodiments illustrated in the accompanying drawings. It should be understood that the following descriptions are not intended to limit the embodiments to one preferred embodiment. To the contrary, it is intended to cover alternatives, modifications, and equivalents as can be included within the spirit and scope of the described embodiments as defined by the appended claims.

[0031] The following disclosure relates to linear accelerators that can be used to accelerate electrons, ions, or other charged particles. In one or all examples, the linear accelerators can be used in X-ray systems, such as X-ray sources used to generate X-rays.Representative applications for X-ray sources and systems include, but are not limited to, imaging, medicine, diagnostics, radiology, radiotherapy, radiography and tomography, and a range of industrial X-ray technologies. The present disclosure focuses on electron beam LINACs, which can be used in X-ray systems; however, the teachings of the present disclosure can be used with LINACs for accelerating any charged particles for any applications. Further, whenever the terms “electrons,” “electron beams,” and the like are used throughout the present disclosure, it is assumed that other charged particles can be used in place of electrons. Charged particles can be referred to as “electrons” for simplicity.

[0032] In some applications, such as for material discrimination while imaging dense objects at high energy, a dual energy mode can be used by an X-ray source to provide improved material discrimination. In the dual energy mode, an electron source, such as a linear accelerator (LINAC), can be run at two energy values in order to produce X-rays with two different sets of energies. The LINAC can run at two energy values, which can be varied or alternated from pulse-to-pulse. Conventional systems can use a complex system to achieve a pulse-to-pulse dual energy7mode, while maintaining stability7and generating electron beams that meet specification requirements. A dual energy mode system can include a LINAC with a radio frequency (RF) source that allows for dual energy operation. The system can include a specially designed modulator capable of running the RF source (e.g., a magnetron) at two different power levels. This can create challenges in matching line and magnetron impedances in the system at two different power levels. Generally, a single electron gun driver can be used in such a system and supplying higher and lower currents to the electron gun can allow for switching between two different electron gun modes.54936-5873-8024'1Attorney Docket No. P323376.WO.01_504935-873Client Docket No. 2024-032-W01

[0033] The following disclosure relates to linear accelerators, which can be used for X-ray sources and the like, with simplified structures that can operate in two modes. More specifically, a linear accelerator of the present disclosure can include two separate LINAC subsections that can be coupled together and driven by a single RF source (e.g., a single magnetron) that operates at a constant RF power. The linear accelerator can be referred to as a folded dual accelerator beam structure or the like. Each of the subsections of the linear accelerator can be angled relative to one another and can be aimed or directed towards an X-ray target surface, which can generate an X-ray beam in response to an incident electron beam. The two subsections can be coupled (e.g., fluidly coupled) via a coupling, a side cavity, or the like, which can allow for RF power to be supplied from the RF source to both of the subsections. The couplings between the two subsections can be provided at an end of each subsection proximal to the X-ray target surface (e.g., a last cavity of each subsection), at an end of each subsection distal to the X-ray target surface (e.g., a first cavity of each subsection), or at any desired location in the subsections. The positions of the couplings can depend on relative angles between the subsections of the linear accelerator. Each subsection can be equipped with an electron gun. The subsections can be positioned side-by-side, such that the electron beams produced by the electron guns and accelerated by the subsections propagate in the same direction. The electron beams can be directed toward separate targets or a common target. To direct the electron beams towards a common target, the subsections can be angled with respect to one another. Accordingly, two separate electron beams can be directed to a common target.

[0034] The subsections of the linear accelerator can have different characteristics or dimensions and can be configured to accelerate electron beams having different characteristics. For example, the subsections can have different lengths. The subsections can accelerate electron beams with two different electron beam energy values. The subsection that produces an electron beam with a higher energy value (referred to as the high-energy subsection) can have an axis orthogonal to the X-ray target surface, which can maximize the energy’ of the electron beam striking the target surface. The subsection that produces an electron beam with a lower energy (referred to as the low-energy subsection) can be angled (e.g., disposed at an oblique angle) relative to the high-energy subsection and the target surface. This can permit the electron beam produced by the low-energy subsection to hit the same target and allow the high-energy subsection and the low-energy subsection to be positioned in close proximity to one another so that the linear accelerator system occupies a minimal volume. In one or all examples, the low-energy subsection can 64936-5873-8024'1Attorney Docket No. P323376.WO.01_504935-873Client Docket No. 2024-032-W01generate an electron beam having a beam energy in a range from about 1 MeV to about 3 MeV and the high-energy subsection can generate an electron beam having a beam energy of about 6 MeV or greater. In operation, RF pulses can be provided from the RF source to the two subsections can be controlled to drive pulses synchronously and alternating pulses can be sent to the electron guns of the two subsections to provide two different electron beam energy values from the subsections of the linear accelerator. The electron guns can be driven by two separate high-voltage (HV) drivers, by a single HV driver with two separate grid driving circuits, or the like.

[0035] By operating both subsections of the linear accelerator with a single RF source, a constant RF power can be used, which can simplify the modulator and LINAC system design. By coupling two subsections of the linear accelerator to one another and coupling both subsections to the same magnetron, the linear accelerator (and both subsections thereof) can have proper and steady operation.

[0036] These and other examples are discussed below with reference to FIGS. 1 through 4. However, those skilled in the art will readily appreciate that the detailed description given herein with respect to these figures is for explanatory purposes only and should not be construed as limiting. Furthermore, as used herein, a system, a method, an article, a component, a feature, or a sub-feature including at least one of a first option, a second option, or a third option should be understood as referring to a system, a method, an article, a component, a feature, or a sub-feature that can include one of each listed option (e.g., only one of the first option, only one of the second option, or only one of the third option), multiple of a single listed option (e.g., two or more of the first option), two options simultaneously (e.g., one of the first option and one of the second option), or combination thereof (e.g., two of the first option and one of the second option).

[0037] FIG. 1 is a cross-sectional view of an X-ray source 100. The X-ray source 100 can include a linear accelerator 102 and a target surface 110. The linear accelerator 102 can be configured to generate one or more electron beams, which can be directed towards the target surface 110. Kinetic energy' from the electron beams can be converted to high energy radiation, such as X-rays, when the electron beams strike the target surface 110 such that an X-ray beam is generated. Although FIG. 1 and subsequent figures are discussed in the context of electron beam linear accelerators used to produce X-rays, the teachings of the present disclosure can be used with linear accelerators for accelerating any charged particles for any applications.74936-5873-8024'1Attorney Docket No. P323376.WO.01_504935-873Client Docket No. 2024-032-W01

[0038] The linear accelerator 102 can be powered by a power source 124 through an RF coupler 122. The linear accelerator 102 can include a first linear accelerator 104 (also referred to as a first linear accelerator subsection or the like) and a second linear accelerator 106 (also referred to as a second linear accelerator subsection or the like), which can each produce an electron beam directed towards the target surface 110. The electron beams produced by the first linear accelerator 104 and the second linear accelerator 106 can have different beam energies. The linear accelerator 102 can switch between operation of the first linear accelerator 104 and the second linear accelerator 106 on a pul e-by -pulse basis to provide dual energy operation and generate electron beams with different beam energies.

[0039] The first linear accelerator 104 can include a first accelerator section 112 and a first electron source 114. The first electron source 114 can be configured to provide an input beam of electrons to the first accelerator section 112, which can then be accelerated by the first accelerator section 112. The accelerated electron beam (referred to as a first electron beam) generated by the first linear accelerator 104 can be directed tow ards the target surface 110.

[0040] The first electron source 114 can be an electron gun, an electron emitter, or the like. The first accelerator section 112 can be coupled to a radio frequency (RF) power source (e.g., the power source 124) and can be configured to accelerate the electron beam produced by the first electron source 114 in response to RF power, supplied by the pow er source 124 to generate the accelerated electron beam. The first accelerator section 112 can include a plurality of cavities arranged along a first acceleration axis El and an acceleration voltage can be applied to electrons across a gap of each cavity. Each of the cavities can have uniform lengths, lengths of the cavities can increase along a length of the first accelerator section 112 (e.g., in a direction towards the target surface 110), combinations thereof, or the like.

[0041] The first accelerator section 112 can have a length ALE The first accelerator section 112 can be positioned a first distance DI from the target surface 110. The first electron beam can have a first electron beam energy'. The first acceleration axis El can be directed toward the target surface 110. The first acceleration axis El can be orthogonal, normal, or perpendicular to a major surface of the target surface 110. In one or all examples, the first acceleration axis El can be angled relative to an angle orthogonal to the target surface 110, such as at an angle within about 5°, within about 10°, or the like from orthogonal to the target surface 110. The first linear accelerator 104 can generate a first84936-5873-8024'1Attorney Docket No. P323376.WO.01_504935-873Client Docket No. 2024-032-W01electron beam with a first electron beam energy greater than about 3.5 MeV, greater than about 6 MeV, in a range from about 3.5 MeV to about 6 MeV, in a range from about 3 MeV to about 7 MeV, about 3.5 MeV, about 6 MeV, or the like.

[0042] The second linear accelerator 106 can be the same as or similar to the first linear accelerator 104. The second linear accelerator 106 can include a second accelerator section 116, a buncher section 118. and a second electron source 120. The second electron source 120 can be configured to provide an input beam of electrons to the buncher section 118, which can be accelerated and bunched by the buncher section 118 and provided to the second accelerator section 116, which can provide further acceleration of the electron beam. The accelerated electron beam (referred to as a second electron beam) generated by the second linear accelerator 106 can be directed towards the target surface 110.

[0043] The second electron source 120 can be an electron gun, an electron emitter, or the like. The buncher section 118 can be configured to form electrons generated by the second electron source 120 into bunches and accelerate those electrons, which can be provided to the second accelerator section 116. The buncher section 118 can be an irregular section of the second linear accelerator 106 (e.g., the buncher section 118 can be formed from cavities having irregular or varying lengths). The buncher section 118 can be positioned between the second electron source 120 and the second accelerator section 116. The buncher section 118 can be coupled to the RF power source (e.g., the power source 124) and can be configured to accelerate the electron beam produced by the second electron source 120 in response to RF power, supplied by the power source 124 to generate the accelerated electron beam. Although a buncher section is not illustrated with respect to the first linear accelerator 104, the first linear accelerator 104 can also include a buncher section.

[0044] The second accelerator section 116 can be coupled to the RF power source (e.g., the power source 124) and can be configured to accelerate the electron beam produced by buncher section 118 in response to RF power, supplied by the power source 124 to generate the accelerated electron beam. The second accelerator section 116 can include a plurality of cavities arranged along a second acceleration axis E2 and an acceleration voltage can be applied to electrons across a gap of each cavity. Each of the cavities can have uniform lengths, lengths of the cavities can increase along a length of the second accelerator section 116 (e.g., in a direction towards the target surface 110), combinations thereof, or the like.

[0045] The first linear accelerator 104 and the second linear accelerator 106 can be used to generate accelerated electron beams having different characteristics and can have different 94936-5873-8024'1Attorney Docket No. P323376.WO.01_504935-873Client Docket No. 2024-032-W01dimensions and characteristics in order to generate the different accelerated electron beams. The second accelerator section 116 can have a length AL2. The length AL2 of the second accelerator section 116 can be less than the length AL1 of the first accelerator section 112. In one or all examples, the length AL2 of the second accelerator section 116 can be equal to or greater than the length AL1 of the first accelerator section 112. The second accelerator section 116 can be positioned a second distance D2 from the target surface 110. The second distance D2 can be less than or equal to the first distance DI between the first accelerator section 112 and the target surface 110. The second acceleration axis E2 can be directed toward the target surface 110. The second acceleration axis E2 can be oblique to the target surface 110. Further, the second acceleration axis E2 can form an angle Al with the first acceleration axis El. The angle Al can be an oblique angle. In one or all examples, the angle Al and an angle between the second acceleration axis E2 and normal to the major surface of the target surface 110 can be in a range from about 10° to about 50°, in a range from about 25° to about 65°, in a range from about 30° to about 45°, about 38°, about 50°, or the like. The second linear accelerator 106 can generate a second electron beam with a second electron beam energy in a range from about 1 MeV to about 3 MeV, in a range from about 0.5 MeV to about 4 MeV, greater than about 0.5 MeV, greater than about 1 MeV, less than about 3 MeV, less than about 4 MeV, or the like. In one or all examples, a ratio of the first electron beam energy of the first electron beam the second electron beam energy of the second electron beam can be in a range from about 1.25 to about 5, in a range from about 1.5 to about 3, or the like.

[0046] The power source 124 can be any power source that can generate RF power. The power source 124 can include a magnetron, a klystron, or the like. The power source 124 can provide power to the first linear accelerator 104 and the second linear accelerator 106. More specifically, the power source 124 can supply RF power to the first accelerator section 112, the buncher section 118, and the second accelerator section 116. In one or all examples, a single power source 124 can provide RF power to both the first linear accelerator 104 and the second linear accelerator 106, which can be supplied at the same RF frequencies and the like. Separate power sources can supply the first electron source 114 and the second electron source 120.

[0047] The RF coupler 122 can couple the power source 124 to the first accelerator section 112 of the first linear accelerator 104. For example, the RF coupler 122 can fluidly couple the power source 124 to the first accelerator section 112 such that RF power is supplied to the first accelerator section 112. The second linear accelerator 106 can be coupled to the 104936-5873-8024'1Attorney Docket No. P323376.WO.01_504935-873Client Docket No. 2024-032-W01power source 124 through the first linear accelerator 104. For example, the linear accelerator 102 can include a side cavity 108 between the first linear accelerator 104 and the second linear accelerator 106. The side cavity 108 can couple the first linear accelerator 104 to the second linear accelerator 106. More specifically, the side cavity 108 can fluidly couple the second accelerator section 116 to the first accelerator section 112 such that RF power is supplied to the second accelerator section 116. The buncher section 118 can be fluidly coupled to the second accelerator section 116 such that RF power is also supplied to the buncher section 118 through the side cavity 108. In one or all examples, the side cavity 108 can provide electrical coupling, magnetic coupling, both, or the like between various sections of the first linear accelerator 104 and the second linear accelerator 106 (e.g., between the first accelerator section 112 and the second accelerator section 116 or between the buncher section 118 and the second accelerator section 116).

[0048] As illustrated in FIG. 1, the side cavity 108 can be positioned at ends of the first accelerator section 112 and the second accelerator section 116 proximal the first electron source 114 and the second electron source 120, respectively, and distal the target surface 110. In one or all examples, the side cavity 108 can couple a first cavity in the first acceleration section 112 (proximal the first electron source 114) to a first cavity in the second acceleration section 116 (proximal the second electron source 120). Other configurations of the RF coupler 122 and the side cavity 108 are also possible. For example, the RF coupler 122 can be provided between the first linear accelerator 104 and the second linear accelerator 106 and can be directly coupled to the first linear accelerator 104 and the second linear accelerator 106. The side cavity 108 can be provided at ends of the first accelerator section 112 and the second accelerator section 116 distal the first electron source 114 and the second electron source 120, respectively. The side cavity 108 can be provided between the first accelerator section 112 and the buncher section 118. The configuration of the RF coupler 122 and the side cavity 108 can depend on relative angles between the first linear accelerator 104, the second linear accelerator 106, and the target surface 110, and can be used to provide the X-ray source 100 with a minimal overall size and volume.

[0049] The target surface 110 can be configured to generate X-rays in response to an electron beam, such as the first electron beam and / or the second electron beam. Although a single target surface 110 is illustrated throughout the present disclosure, in one or all examples, two target surfaces 110 can be included and the first linear accelerator 104 and the second linear accelerator 106 can each be directed towards one of the target surfaces 114936-5873-8024'1Attorney Docket No. P323376.WO.01_504935-873Client Docket No. 2024-032-W01110. In examples in which two target surfaces 110 are included, each of the target surfaces 110 can have a different thickness and / or can be formed from a different material. The target surface 110 can be any material that can convert incoming electrons to X-rays. In one or all examples, the target surface 110 can be formed of a metal having a high atomic number and a high melting point, such as tungsten, molybdenum, rhodium, copper, or an alloy thereof. Although specific materials are discussed for the target surface 110, any other appropriate material can be used.

[0050] In operation, the linear accelerator 102 can be configured to switch between generating the first electron beam through the first linear accelerator 104 and the first electron source 114 and generating the second electron beam through the second linear accelerator 106 and the second electron source 120. This can be used to produce the first electron beam and the second electron beam, which have different electron beam energies, which can be used to produce higher energy X-rays and lower energy X-rays, respectively, from the target surface 110. Producing X-rays with two different energy levels from the X-ray source 100 can allow for improved material discrimination, such as with certain materials. In one or all examples, the linear accelerator 102 can be configured to switch between generating the first electron beam and the second electron beam from pulse to pulse. The linear accelerator 102 can be configured to switch between generating the first electron beam and generating the second electron beam by switching power between the first electron source 114 and the second electron source 120. For example, pulses of power can be supplied alternately to the first electron source 114 and the second electron source 120 to switch operating between the first electron beam and the second electron beam. This can allow quickly alternating between the higher energy X-rays and the lower energy X-rays, such as from pulse to pulse. Further, both the first linear accelerator 104 and the second linear accelerator 106 of the linear accelerator 102 can be powered by the power source 124, which can reduce costs, reduce size, and simplify structure of the X-ray source 100, while allowing a single power source to power the power source 124.

[0051] FIG. 2 is a cross-sectional view of an X-ray source 150. The X-ray source 150 can be the same as or similar to the X-ray source 100, discussed above with respect to FIG. 1, and can include components the same as or similar to the X-ray source 100. The X-ray¬ source 150 can include a linear accelerator 152, a target surface 110, an RF coupler 122. and a power source 124. The linear accelerator 102 can include a first linear accelerator 104 and a second linear accelerator 156, which can accelerate electrons with different beam energies.124936-5873-8024'1Attorney Docket No. P323376.WO.01_504935-873Client Docket No. 2024-032-W01

[0052] The second linear accelerator 156 can include a second accelerator section 11 , a buncher section 118, and a second electron source 120. The second electron source 120 can be configured to provide an input beam of electrons to the buncher section 118, which can be accelerated and bunched by the buncher section 118 and provided to the second accelerator section 116, which can provide further acceleration of the electron beam. The accelerated electron beam (referred to as a second electron beam) generated by the second linear accelerator 156 can be directed towards the target surface 110.

[0053] The second electron source 120 can be an electron gun, an electron emitter, or the like. The buncher section 118 can be configured to form electrons generated by the second electron source 120 into bunches and accelerate those electrons, which can be provided to the second accelerator section 116. The buncher section 118 can be an irregular section of the second linear accelerator 156 (e.g., the buncher section 118 can be formed from cavities having irregular or varying lengths). The buncher section 118 can be positioned between the second electron source 120 and the second accelerator section 116. The buncher section 118 can be coupled to the RF power source (e.g., the power source 124) and can be configured to accelerate the electron beam produced by the second electron source 120 in response to RF power, supplied by the power source 124 to generate the accelerated electron beam.

[0054] The second accelerator section 116 can be coupled to the RF power source (e.g., the power source 124) and can be configured to accelerate the electron beam produced by buncher section 118 in response to RF power, supplied by the power source 124 to generate the accelerated electron beam. The second accelerator section 116 can include a plurality of cavities arranged along a third acceleration axis E3 and an acceleration voltage can be applied to electrons across a gap of each cavity. Each of the cavities can have uniform lengths, lengths of the cavities can increase along a length of the second accelerator section 116 (e.g., in a direction towards the target surface 110), combinations thereof, or the like.

[0055] The first linear accelerator 104 and the second linear accelerator 156 can be used to generate accelerated electron beams having different characteristics and can have different dimensions and characteristics in order to generate the different accelerated electron beams. The second accelerator section 116 can have a length AL2. The length AL2 of the second accelerator section 116 can be less than a length AL1 of a first accelerator section 112 of the first linear accelerator 104. In one or all examples, the length AL2 of the second accelerator section 116 can be equal to or greater than the length AL1 of the first accelerator section134936-5873-8024'1Attorney Docket No. P323376.WO.01_504935-873Client Docket No. 2024-032-W01112. The second accelerator section 116 can be positioned a third distance D3 from the target surface 110. The third distance D3 can be less than or equal to a first distance DI between the first accelerator section 112 and the target surface 110. The third acceleration axis E3 can be directed toward the target surface 110. The third acceleration axis E3 can be oblique to the target surface 110. Further, the third acceleration axis E3 can form an angle A2 with the first acceleration axis El. The angle A2 can be an oblique angle. In one or all examples, the angle A2 and an angle between the third acceleration axis E3 and normal to the major surface of the target surface 110 can be in a range from about 30° to about 90°, in a range from about 45° to about 65°, in a range from about 40° to about 80°, about 38°, about 50°, or the like. The second linear accelerator 156 can generate a second electron beam with a second electron beam energy in a range from about 1 MeV to about 3 MeV, in a range from about 0.5 MeV to about 4 MeV, greater than about 0.5 MeV, greater than about 1 MeV, less than about 3 MeV, less than about 4 MeV, or the like. In one or all examples, a ratio of the first electron beam energy of the first electron beam the second electron beam energy of the second electron beam can be in a range from about 1.25 to about 5, in a range from about 1.5 to about 3, or the like.

[0056] RF power from the power source 124 can be supplied through the RF coupler 122 to the first accelerator section 112, the buncher section 118, and the second accelerator section 116 of the first linear accelerator 104 and the second linear accelerator 156. The RF coupler 122 can fluidly couple the power source 124 to the first accelerator section 112 such that RF power is supplied to the first accelerator section 112. The second linear accelerator 156 can be coupled to the power source 124 through the first linear accelerator 104. For example, the linear accelerator 102 can include a side cavity 158 between the first linear accelerator 104 and the second linear accelerator 156. The side cavity 158 can couple the first linear accelerator 104 to the second linear accelerator 156. More specifically, the side cavity 158 can fluidly couple the second accelerator section 116 to the first accelerator section 112 such that RF power is supplied to the second accelerator section 116. The buncher section 118 can be fluidly coupled to the second accelerator section 116 such that RF power is also supplied to the buncher section 118 through the side cavity 158. In one or all examples, the side cavity 158 can provide electrical coupling, magnetic coupling, both, or the like between various sections of the first linear accelerator 104 and the second linear accelerator 156 (e.g., between the first accelerator section 112 and the second accelerator section 116 or between the buncher section 118 and the second accelerator section 116).144936-5873-8024'1Attorney Docket No. P323376.WO.01_504935-873Client Docket No. 2024-032-W01

[0057] As illustrated in FIG. 2, the side cavity 158 can be positioned at ends of the first accelerator section 112 and the second accelerator section 116 distal the first electron source 114 and the second electron source 120, respectively, and proximal the target surface 110. In one or all examples, the side cavity 158 can couple a last cavity in the first acceleration section 112 (distal the first electron source 114) to a last cavity in the second acceleration section 116 (distal the second electron source 120). Other configurations of the RF coupler 122 and the side cavity 158 are also possible. For example, the RF coupler 122 can be provided between the first linear accelerator 104 and the second linear accelerator 156 and can be directly coupled to the first linear accelerator 104 and the second linear accelerator 156. The side cavity 158 can be provided at ends of the first accelerator section 112 and the second accelerator section 116 proximal the first electron source 114 and the second electron source 120. respectively. The side cavity 158 can be provided between the first accelerator section 112 and the buncher section 118. The configuration of the RF coupler 122 and the side cavity 158 can depend on relative angles between the first linear accelerator 104, the second linear accelerator 156, and the target surface 110, and can be used to provide the X-ray source 100 with a minimal overall size and volume.

[0058] In operation, the linear accelerator 102 can be configured to switch between the first linear accelerator 104 and the second linear accelerator 156. This can be used to produce the first electron beam and the second electron beam, which have different electron beam energies. Operating at two different electron beam energies can allow for improved material discrimination, such as with certain materials. In one or all examples, the linear accelerator 102 can be configured to switch between the first linear accelerator 104 and the second linear accelerator 156 from pulse to pulse. The linear accelerator 102 can be configured to switch between the first electron source 114 and the second electron source 120 to provide different energies. Operating at two energies can allow for improved material discrimination, such as with certain materials.

[0059] Much like the X-ray source 100 of FIG. 1, the X-ray source 150 can switch between producing the first electron beam and the second electron beam quickly, such as from pulse to pulse, and the X-ray source 150 can quickly switch between producing higher energy X-rays and lower energy X-rays. This provides greater control over the X-rays generated by the X-ray source 150 and can be used to provide improved imaging more quickly by the X-ray source 150. Further, the X-ray source 150 can include a single power source 124, which can reduce costs of the X-ray source 150, simplifies the X-ray source 150, allows power from a single source to be supplied to the power source 124, and the like.154936-5873-8024'1Attorney Docket No. P323376.WO.01_504935-873Client Docket No. 2024-032-W01

[0060] FIG. 3 is a block diagram of an X-ray source 300. The X-ray source 300 can be the same as or similar to the X-ray sources 100, 150, discussed above with respect to FIGS. 1 and 2. The X-ray source 300 can include components the same as or similar to components of the X-ray sources 100, 150. The X-ray source 300 can include a first linear accelerator 302, a first electron source 304, a second linear accelerator 306, a second electron source 308, a target surface 310, a power source 312, an RF coupler 314, a first high voltage driver 316, and a second high voltage driver 318. The first electron source 304 can produce electrons, which are accelerated by the first linear accelerator 302 to produce a first electron beam at a first beam energy. The second electron source 308 can produce electrons, which are accelerated by the second linear accelerator 306 to produce a second electron beam at a second beam energy different from the first beam energy. The first electron beam and the second electron beam can be directed at the target surface 310 and can be used to generate X-rays at two different energy levels. The first high voltage driver 316 can drive the first electron source 304 and the second high voltage driver 318 can drive the second electron source 308. The X-ray source 300 can switch between generating higher-energy electron beams and lower energy electron beams by switching between the first electron source 304 / first linear accelerator 302 and the second electron source 308 / second linear accelerator 306 using the first high voltage driver 316 and the second high voltage driver 318.

[0061] The first electron source 304 can be an electron gun, an electron emitter, or the like. The first electron source 304 can be configured to provide an input beam of electrons to generate a first electron beam. The first linear accelerator 302 can be configured to accelerate the electron beam in response to RF power, supplied by the power source 312, to generate an accelerated electron beam, or the first electron beam. The first electron beam can have a first electron beam energy’. In one or all examples, the first electron beam energy can be greater than about 3.5 MeV, greater than about 6 MeV, in a range from about 3.5 MeV to about 6 MeV, in a range from about 3 MeV to about 7 MeV, about 3.5 MeV, about 6 MeV, or the like. The first linear accelerator 302 can be configured to direct the first electron beam, or charged particles, towards the target surface 310 to produce X-rays. The first linear accelerator 302 can be configured to direct the first electron beam, or charged particles, towards the target surface 310 at an angle orthogonal, normal, or perpendicular to the target surface 310. In one or all examples, the first electron beam can be angled relative to an angle orthogonal to the target surface 310, such as at an angle within about 5°, within about 10°, or the like from orthogonal to the target surface 310.164936-5873-8024'1Attorney Docket No. P323376.WO.01_504935-873Client Docket No. 2024-032-W01

[0062] The first linear accelerator 302 can include a plurality of cavities. The plurality of cavities can have a uniform length, a gradually increasing length, or a combination thereof. The first linear accelerator 302 can have a first length. The first linear accelerator 302 can be positioned a first distance from the target surface 310. The first linear accelerator 302 can have a first acceleration axis. The first acceleration axis can be directed toward the target surface 310. The first acceleration axis can be orthogonal, normal, or perpendicular to the target surface 310. The first linear accelerator 302 can be coupled to the first electron source 304.

[0063] The second electron source 308 can be an electron gun, an electron emitter, or the like. The second electron source 308 can be configured to provide an input beam of electrons. The second linear accelerator 306 can be configured to accelerate the electron beam in response to power, supplied by the power source 312, to generate an accelerated electron beam, or the second electron beam. The second electron beam can have a second electron beam energy. The second electron beam energy can be less than the first electron beam energy. In one or all examples, the second electron beam energy can be in a range from about 1 MeV to about 3 MeV, in a range from about 0.5 MeV to about 4 MeV, greater than about 0.5 MeV, greater than about 1 MeV, less than about 3 MeV, less than about 4 MeV, or the like. In one or all examples, the second electron beam energy can be greater than the first electron beam energy. The second linear accelerator 306 can be configured to direct the second electron beam, or charged particles, towards the target surface 310 to produce X-rays. The second linear accelerator 306 can be configured to direct the second electron beam, or charged particles, towards the target surface 310 at an angle oblique to the target surface 310 and the first electron beam. In one or all examples, the second electron beam can be angled relative to an angle orthogonal to the target surface 310 and the first electron beam at an angle in a range from about 10° to about 50°, in a range from about 10° to about 90°, in a range from about 30° to about 60°, in a range from about 25° to about 65°, in a range from about 30° to about 45°, about 38°, about 50°, or the like.

[0064] The second linear accelerator 306 can include a plurality of cavities. The plurality’ of cavities can have a uniform length, a gradually increasing length, or a combination thereof. The second linear accelerator 306 can have a second length. The second length of the second linear accelerator 306 can be less than the first length of the first linear accelerator 302. In one or all examples, the second length of the second accelerator section 306 can be equal to or greater than the first length of the first accelerator section 302. The second linear accelerator 306 can be positioned a second distance from the target surface 174936-5873-8024'1Attorney Docket No. P323376.WO.01_504935-873Client Docket No. 2024-032-W01310. The first distance between the first linear accelerator 302 and the target surface 310 can be greater than the second distance between the second linear accelerator 306 and the target surface 310. In one or all examples, the first distance between the first linear accelerator 302 and the target surface 310 can be equal to or less than the second distance between the second linear accelerator 306 and the target surface 310. The second linear accelerator 306 can have a second acceleration axis. The second acceleration axis can be directed toward the target surface 310. The second acceleration axis can be angled at an angle oblique to the target surface 310 and / or the first acceleration axis of the first linear accelerator 302. In one or all examples, the second acceleration axis can be angled relative to the target surface 310 and / or the first acceleration axis at an angle in a range from about 10° to about 50°, in a range from about 10° to about 90°, in a range from about 30° to about 60°, in a range from about 25° to about 65°, in a range from about 30° to about 45°, about 38°, about 50°. or the like.

[0065] The first linear accelerator 302 and the second linear accelerator 306 can be coupled together. In one or all examples, the first linear accelerator 302 can couple to the second linear accelerator 306 via a side cavity. The side cavity can fluidly couple the first linear accelerator 302 and the second linear accelerator 306 and can allow power to be supplied to both the first linear accelerator 302 and the second linear accelerator 306 from the same power source (e.g., the power source 312). The side cavity can couple the first linear accelerator 302 and the second linear accelerator 306 through cavities of the first linear accelerator 302 and the second linear accelerator 306 proximal the target surface 310 (e.g., distal the first electron source 304 and the second electron source 308), proximal the first electron source 304 and the second electron source 308 (e.g., distal the target surface 310), or located anywhere else along the first linear accelerator 302 and the second linear accelerator 306. Moreover, in one or all examples, the RF coupler can be coupled to the first linear accelerator 302 and the second linear accelerator 306 without an additional side channel being included between the first linear accelerator 302 and the second linear accelerator 306.

[0066] The target surface 310 can be configured to generate X-rays in response to an electron beam, such as the first electron beam and / or the second electron beam. Although a single target surface 310 is illustrated throughout the present disclosure, in one or all examples, t o target surfaces 310 can be included and the first linear accelerator 302 and the second linear accelerator 306 can each be directed towards one of the target surfaces 310. In examples in w hich two target surfaces 310 are included, each of the target surfaces 184936-5873-8024'1Attorney Docket No. P323376.WO.01_504935-873Client Docket No. 2024-032-W01310 can have a different thickness and / or can be formed from a different material. The target surface 310 can be any material that can convert incoming electrons to X-rays. In one or all examples, the target surface 310 can be formed of a metal having a high atomic number and a high melting point, such as tungsten, molybdenum, rhodium, copper, or an alloy thereof. Although specific materials are discussed for the target surface 310, any other appropriate material can be used.

[0067] The power source 312 can supply power to the first linear accelerator 302 and the second linear accelerator 306. The power source 312 can convert electrical power to RF power. The power source 312 can include a magnetron, a klystron, or the like. In one or all examples, the power source 312 can be configured to generated RF power at a desired frequency, such as about 3 GHz, about 10 GHz. or the like. However, the power source 312 can supply RF power at any desired frequency, depending on the configuration of the first linear accelerator 302 and the second linear accelerator 306. In one or all examples, the pow er source 312 can provide the same power for the first linear accelerator 302 and the second linear accelerator 306.

[0068] The RF coupler 314 can couple the power source 312 to the first linear accelerator 302 and / or the second linear accelerator 306. For example, the RF coupler 314 can fluidly couple the power source 312 to the first linear accelerator 302. which can be fluidly coupled to the second linear accelerator 306 through a side cavity. Other configurations are also possible, such as fluidly coupling the RF coupler 314 to both the first linear accelerator 302 and the second linear accelerator 306 or fluidly coupling the RF coupler 314 to the second linear accelerator 306 and fluidly coupling the second linear accelerator 306 to the first linear accelerator 302 through a side cavity.

[0069] The first high voltage driver 316 can be configured to cause a high-voltage pulse to be provided to the first electron source 304. The first high voltage driver 316 can be configured to control the pulses provided to the first electron source 304. In operation, the first electron source 304 can be controlled by the first high voltage driver 316 to deliver pulses of electrons to the first linear accelerator 302. Pulses of the first electron beam can then be accelerated and provided to the target surface 310 in response to the high-voltage pulses provided by the first high voltage driver 316.

[0070] The second high voltage driver 318 can be configured to cause a high-voltage pulse to be provided to the second electron source 308. The second high voltage driver 318 can be configured to control the pulses provided to the second electron source 308. In operation,194936-5873-8024'1Attorney Docket No. P323376.WO.01_504935-873Client Docket No. 2024-032-W01the second electron source 308 can be controlled by the second high voltage driver 318 to deliver pulses of electrons to the second linear accelerator 306. Pulses of the first electron beam can then be accelerated and provided to the target surface 310 in response to the high-voltage pulses provided by the second high voltage driver 318.

[0071] The first high voltage driver 316 and the second high voltage driver 318 can be configured to control the X-ray source 300 to alternate the delivery of pulses between the first electron source 304 and the second electron source 308. This, in turn can be used to alternate delivery of the first electron beam and the second electron beam, having two different beam energies, to the target surface 310. Higher energy X-rays can be generated as the first electron beam collides with the target surface 310 and lower energy X-rays can be generated as the second electron beam collides with the target surface 310. Thus, the first high voltage driver 316 and the second high voltage driver 318 can be used to generate higher energy X-rays and lower energy X-rays from the X-ray source 300. The first high voltage driver 316 and the second high voltage driver 318 can be used to switch between the first electron beam generated by the first electron source 304 and the first linear accelerator 302 and the second electron beam generated by the second electron source 308 and the second linear accelerator 306 very quickly, such as from pulse to pulse, which gives greater control over the X-rays generated by the X-ray source 300. Further, the X-ray source 300 can include a single power source 312. which can reduce costs of the X-ray source 300, simplifies the X-ray source 300, allows power from a single source to be supplied to the power source 312, and the like.

[0072] FIG. 4 is a block diagram of an X-ray source 350. The X-ray source 350 can be the same as or similar to the X-ray sources 100. 150, 300, discussed above with respect to FIGS. 1 through 3. The X-ray source 350 can include components the same as or similar to components of the X-ray sources 100, 150, 300. The X-ray source 350 can include a first linear accelerator 302, a first electron source 304, a second linear accelerator 306, a second electron source 308. a target surface 310, a power source 312, and a RF coupler 314. The X-ray source 350 can differ from the X-ray source 300 in that the X-ray source 350 includes a high voltage driver 320, a first high voltage grid driving circuit 322, and a second high voltage grid driving circuit 324. The high voltage driver 320, the first high voltage grid driving circuit 322, and the second high voltage grid driving circuit 324 can replace the first high voltage driver 316 and the second high voltage driver 318 of the X-ray source 300.204936-5873-8024'1Attorney Docket No. P323376.WO.01_504935-873Client Docket No. 2024-032-W01

[0073] The high voltage driver 320 can be configured to cause a high-voltage pulse to be provided to the first electron source 304 and the second electron source 308 through the first high voltage grid driving circuit 322 and the second high voltage grid driving circuit 324, respectively. The first high voltage grid driving circuit 322 can be configured to control the pulses provided to the first electron source 304. The second high voltage grid driving circuit 324 can be configured to control the pulses provided to the second electron source 308.

[0074] In operation, the first electron source 304 can be controlled by the high voltage driver 320 and the first high voltage grid driving circuit 322 to deliver of electrons to the first linear accelerator 302. Pulses of the first electron beam can then be accelerated and provided pulses to the target surface 310 in response to the high-voltage pulses provided by the high voltage driver 320 and the first high voltage grid driving circuit 322. The second electron source 308 can be controlled by the high voltage driver 320 and the second first high voltage grid driving circuit 324 to deliver of electrons to the first linear accelerator 302. Pulses of the first electron beam can then be accelerated and provided pulses to the target surface 310 in response to the high-voltage pulses provided by the high voltage driver 320 and the second first high voltage grid driving circuit 324. The first electron source 304 and the second electron source 308 can

[0075] The high voltage driver 320, the first high voltage grid driving circuit 322, and the second high voltage grid driving circuit 324 can be configured to control the X-ray source 350 to alternate the del i \ er\ of pulses between the first electron source 304 and the second electron source 308. This, in turn can be used to alternate delivery of the first electron beam and the second electron beam, having two different beam energies, to the target surface 310. Higher energy X-rays can be generated as the first electron beam collides with the target surface 310 and lower energy X-rays can be generated as the second electron beam collides with the target surface 310. Thus, the high voltage driver 320, the first high voltage grid driving circuit 322, and the second high voltage grid driving circuit 324 can be used to generate higher energy X-rays and lower energy X-rays from the X-ray source 350. The high voltage driver 320, the first high voltage grid driving circuit 322, and the second high voltage grid driving circuit 324 can be used to switch between the first electron beam generated by the first electron source 304 and the first linear accelerator 302 and the second electron beam generated by the second electron source 308 and the second linear accelerator 306 very quickly, such as from pulse to pulse, which gives greater control over the X-rays generated by the X-ray source 350. Further, the X-ray source 350 can include a single power source 312, which can reduce costs of the X-ray source 350, simplifies the X-ray 214936-5873-8024'1Attorney Docket No. P323376.WO.01_504935-873Client Docket No. 2024-032-W01source 350, allows power from a single source to be supplied to the power source 312, and the like.

[0076] FIG. 5 illustrates a flowchart of a method 500 of operating a linear accelerator. The method can be used to operate any of the X-ray sources 100, 150, 300, 350, discussed above with respect to FIGS. 1 through 4. The method 500 can include a block 502 in which a first electron beam is generated, a block 504 in which a second electron beam is generated, and a block 506 in which a constant power is supplied.

[0077] In block 502, the first electron beam is generated. The first electron beam can be generated by producing electrons and accelerating the electrons towards a target surface. The electrons can be produced by a first electron source, such as an electron gun, an electron emitter, or the like. The electrons can be accelerated through a first linear accelerator. The first electron source can be driven by a first high-voltage pulse, which can be driven by a high-voltage driver with or without a first grid driving circuit.

[0078] The first electron beam can have a first electron beam energy. By directing the first electron beam at a target surface, X-rays can be generated with a first energy level. The first electron beam can be emitted or driven toward the target surface at a first angle. The first angle can be orthogonal to the target surface. The first linear accelerator can be positioned a first distance from the target surface.

[0079] In block 504, the second electron beam is generated. The second electron beam can be generated by producing electrons and accelerating the electrons towards the target surface. The electrons can be produced by a second electron source, such as an electron gun, an electron emitter, or the like. The electrons can be accelerated through a second linear accelerator. The second electron source can be driven by a second high-voltage pulse, which can be driven by a high-voltage driver (e.g.. the same or a different high-voltage driver from the high-voltage driver used to drive the first electron source) with or without a second grid driving circuit.

[0080] The second electron beam can have a second electron beam energy. The second electron beam energy can be different from the first electron beam energy. By directing the second electron beam at a target surface, X-rays can be generated with a second energy level different from the first energy level. The second electron beam can be emitted or driven toward a target surface at a second angle. The second angle can be different from the first angle. The second angle can be oblique to the target surface and / or the first angle. The second linear accelerator can be positioned a second distance from the target surface, which 224936-5873-8024'1Attorney Docket No. P323376.WO.01_504935-873Client Docket No. 2024-032-W01can be the same or different from the first distance. In one or all examples, the second electron beam energy can be less than the first electron beam energy, the second energy¬ level of X-rays generated in response to the second electron beam can be less than the first energy level of X-rays generated in response to the first electron beam, and the second distance can be greater than the first distance; however, any of these relationships can be changed.

[0081] High voltage drivers and / or the first and second grid driving circuits can be used to switch between blocks 502 and 504 such that the first electron beam and first X-rays generated in response thereto can be alternated with the second electron beam and second X-rays generated in response thereto. Utilizing X-rays at two energy levels can be used to provide improved material discrimination. Using the high-voltage drivers and / or the first and second grid driving circuits can simplify a system used to alternate between X-ray energy levels, reduce cost, reduce system complexity, and improve the reliability- of an X-ray system.

[0082] In block 506, the constant power is supplied. The constant power can be supplied to the first and second linear accelerators, such as by fluidly coupling the first and second linear accelerators together. As described above, a power source (e.g., an RF power source) can be coupled to the first linear accelerator and / or the second linear accelerator and the first and second linear accelerators can be coupled to one another, such as through a side cavity. The constant power can be supplied to the first and second linear accelerators while performing blocks 502 and 504. The constant power can be supplied by a magnetron a klystron, or the like. By supplying constant power to the first and second linear accelerators, a single power source can be used to supply the power, which reduces cost, complexity, and size of the X-ray system. Further, coupling both the first and second linear accelerators to the single pow er supply ensures proper and steady operation of both the first and second linear accelerators.

[0083] The foregoing description, for purposes of explanation, used specific nomenclature to provide a thorough understanding of the described embodiments. However, it w ill be apparent to one skilled in the art that the specific details are not required in order to practice the described embodiments. Thus, the foregoing descriptions of the specific embodiments described herein are presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the embodiments to the precise forms disclosed. It will234936-5873-8024'1Attorney Docket No. P323376.WO 01_504935-873Client Docket No. 2024-032-W01be apparent to one of ordinary skill in the art that many modifications and variations are possible in view of the above teachings.244936-5873-8024'1

Claims

Attorney Docket No. P323376.WO.01_504935-873Client Docket No. 2024-032-W01CLAIMSWhat is claimed is:

1. A linear accelerator comprising:a first accelerator section having a first acceleration axis;a second accelerator section having a second acceleration axis oblique relative to the first acceleration axis; anda radiofrequency (RF) source coupled to the first accelerator section and the second accelerator section.

2. The linear accelerator of claim 1, wherein:the first accelerator section comprises a first electron source; andthe second accelerator section comprises a second electron source.

3. The linear accelerator of claim 1, wherein the first acceleration axis and the second acceleration axis are directed toward a target surface.

4. The linear accelerator of claim 1, wherein the first accelerator section is configured to operate at a first energy' greater than a second energy’ at which the second accelerator section is configured to operate.

5. The linear accelerator of claim 4, wherein:the first acceleration axis and the acceleration second axis are directed toward a target surface;the first acceleration axis is orthogonal to the target surface; andthe second acceleration axis is oblique to the target surface.

6. The linear accelerator of claim 4, wherein the first accelerator section has a first length greater than a second length of the second accelerator section.

7. The linear accelerator of claim 4, wherein a first distance between the first accelerator section and a target surface is greater than a second distance between the second accelerator section and the target surface.254936-5873-8024'1Attorney Docket No. P323376.WO.01_504935-873Client Docket No. 2024-032-W018. The linear accelerator of claim 1, wherein:the RF source is coupled to the first accelerator section; andthe RF source is coupled to the second accelerator section through the first accelerator section.

9. An X-ray source comprising:a first linear accelerator comprising a first electron gun;a second linear accelerator comprising a second electron gun; anda side cavity coupling the first linear accelerator to the second linear accelerator; wherein the first linear accelerator and the second linear accelerator are configured to direct charged particles toward a target surface to produce X-rays.

10. The X-ray source of claim 9, wherein the first linear accelerator and the second linear accelerator are coupled to a magnetron.

11. The X-ray source of claim 9, wherein:the first linear accelerator is configured to generate a first electron beam having a first electron beam energy; andthe second linear accelerator is configured to generate a second electron beam having a second electron beam energy less than the first electron beam energy.

12. The X-ray source of claim 11, wherein:the first linear accelerator is configured to direct the first electron beam towards the target surface at an angle normal to the target surface; andthe second linear accelerator is configured to direct the second electron beam towards the target surface at an angle oblique to the first electron beam and the target surface.

13. The X-ray source of claim 11, wherein:the first linear accelerator has a first length; andthe second linear accelerator has a second length less than the first length.264936-5873-8024'1Attorney Docket No. P323376.WO.01_504935-873Client Docket No. 2024-032-W0114. A method of operating a linear accelerator comprising:driving a first high-voltage pulse to generate a first electron beam having a first electron beam energy;driving a second high-voltage pulse to generate a second electron beam having a second electron beam energy different from the first electron beam energy; and supplying a constant RF power while driving the first high-voltage pulse and the second high-voltage pulse.

15. The method of claim 14, wherein the first high-voltage pulse and the second high-voltage pulse are driven by a high-voltage driver.

16. The method of claim 15, wherein:the first high-voltage pulse is driven by a first grid-driving circuit; andthe second high-voltage pulse is driven by a second grid-driving circuit.

17. The method of claim 14, wherein:the first high-voltage pulse is driven by a first high-voltage driver; andthe second high-voltage pulse is driven by a second high-voltage driver.

18. The method of claim 14, wherein:the first high-voltage pulse is driven to a first electron source and the first electron beam is generated by a first accelerator subsection;the second high-voltage pulse is driven to a second electron source and the second electron beam is generated by a second accelerator subsection; andthe constant RF power is supplied by a magnetron coupled to the first accelerator subsection and the second accelerator subsection.

19. The method of claim 14, wherein the first electron beam and the second electron beam are emitted towards a target at different angles.

20. The method of claim 14, wherein:the first electron beam is driven towards a target at an angle orthogonal to the target; and274936-5873-8024'1Attorney Docket No. P323376.WO 01_504935-873Client Docket No. 2024-032-W01the second electron beam is driven towards the target at an angle oblique to the target.284936-5873-8024'1

Images