Systems, devices, and methods for ion beam modulation

Abstract

Embodiments of systems, apparatuses, and methods relate to an ion beam source system. The ion source is configured to provide a negative ion beam to a tandem accelerator system downstream of the ion source, and a modulator system connected to an extraction electrode of the ion source is configured to bias the extraction electrode for a duration sufficient to maintain stability of an acceleration voltage of the tandem accelerator system.

Description

[0001] Cross-references to related applications

[0002] This application claims priority to U.S. Provisional Application Serial No. 63 / 044,314, filed June 25, 2020, entitled “Systems, Apparatus, and Methods for Ion Beam Modulation,” the contents of which are incorporated herein by reference in their entirety. Technical Field

[0003] The topics described herein generally relate to systems, apparatus, and methods for modulating beams in a beam system. Background Technology

[0004] Boron neutron capture therapy (BNCT) is a physical therapy used to treat many types of cancer—including some of the most difficult to treat. BNCT is a technique that selectively targets tumor cells while using boron compounds to protect normal cells. A boron-containing substance is injected into the bloodstream, and the boron accumulates in the tumor cells. The patient then receives neutron radiation therapy (e.g., in the form of a neutron beam). The neutrons react with the boron, killing the tumor cells without harming normal cells. Long-term clinical studies have demonstrated that neutron beams with an energy spectrum in the 3–30 keV range are more suitable for achieving more effective cancer treatment while reducing the patient's radiation load. This energy spectrum or range is often referred to as hyperthermia.

[0005] Most conventional methods for generating superthermal neutrons (e.g., superthermal neutron beams) are based on the nuclear reaction of protons (e.g., proton beams) with beryllium or lithium (e.g., beryllium targets or lithium targets).

[0006] A tandem accelerator is an electrostatic accelerator that uses a single high-voltage terminal to accelerate ion particles in a two-step process. The high voltage is used to create, for example, an increasingly larger positive gradient, which is applied to an incoming negative beam to accelerate it. The tandem accelerator then converts the negative beam into a positive beam, and the high voltage is used again to create a reverse, decreasing positive gradient that accelerates (e.g., propels) the positive beam from the tandem accelerator. Because the high voltage can be used twice, producing a proton beam with particle energies of 3 MeV typically requires only 1.5 MV of accelerating voltage, which is within the capabilities of modern electrical insulation technology. Furthermore, the ion source of a tandem accelerator is at ground potential, making the ion source easier to control and maintain.

[0007] The proton beam provided by a tandem accelerator for boron neutron capture therapy (BNCT) has an energy level preferred for both therapeutic efficacy and use by downstream devices (e.g., for efficient neutron production on a lithium (Li) target). A specific flux density threshold is required for reasonably short treatment times, and a minimum proton beam current occurs with this necessary threshold. The power density associated with such proton beams significantly exceeds the safety limits of the materials used in the components of the neutron beam system.

[0008] Conventional methods for protecting beam equipment include aligning high-power beams with significantly reduced beam currents. Beam alignment works well for relatively low-current beams when the beam shape and position are independent of the beam's self-space charge. However, for tandem accelerators where beam parameters include much higher beam currents (and where self-space charge has a significant effect on beam shape), beam alignment becomes difficult with reduced currents.

[0009] Traditional methods for protecting beam equipment also include beam modulation for accelerator types, such as radio frequency quadrupole (RFQ) accelerators or linear accelerators (e.g., not tandem accelerators). Beam modulation is used in such applications to reduce the average beam power when it is not possible to reduce the beam current. This approach is well-suited for accelerator types such as RFQ or linear accelerators (“linear accelerators”) because the beam current is focused. However, for DC accelerators such as tandem accelerators, modulation is not yet applicable because it is not possible to change the load of a DC accelerator from zero to its nominal value and back within a short time.

[0010] For these and other reasons, there is a need for improved, efficient and compact systems, devices and methods to modulate ion beam sources so that beam power can be reduced for the safety and protection of neutron beam system equipment while maintaining efficacy. Summary of the Invention

[0011] Embodiments of the systems, apparatus, and methods relate to beam source systems capable of modulating charged particle beams. An ion source is configured to provide a negative ion beam to a tandem accelerator system downstream of the ion source, and a modulator system connected to the extraction electrodes of the ion source is configured to bias the extraction electrodes for a duration sufficient to maintain the acceleration voltage stability of the tandem accelerator system.

[0012] Other systems, apparatuses, methods, features, and advantages of the subject matter described herein will be apparent to or will become apparent to those skilled in the art upon review of the following figures and detailed description. It is intended that all such additional systems, methods, features, and advantages are included within the scope of this description, the subject matter described herein, and protected by the appended claims. Features of exemplary embodiments should in no way be construed as limiting the appended claims, where no explicit statement of those features is made in the claims. Attached Figure Description

[0013] The details of the subjects described herein, both in terms of their structure and operation, become apparent from the accompanying drawings, in which the same reference numerals denote the same parts. The components in the drawings are not necessarily drawn to scale, but rather emphasize the principles of the illustrated subjects. Furthermore, all illustrations are intended to convey concepts, where relative dimensions, shapes, and other detailed properties may be shown schematically rather than literally or precisely.

[0014] Figure 1A This is a schematic diagram of an exemplary embodiment of a neutron beam system for use with embodiments of the present disclosure.

[0015] Figure 1B This is a schematic diagram of an exemplary embodiment of a neutron beam system used in boron neutron capture therapy (BNCT).

[0016] Figure 2 An exemplary pre-accelerator system or ion beam injector for use with embodiments of this disclosure is illustrated.

[0017] Figure 3A yes Figure 2 A perspective view of the ion source and the ion source vacuum chamber shown.

[0018] Figure 3B It is a description Figure 3A An exploded perspective view of an exemplary embodiment of the single lens shown.

[0019] Figure 4A An exemplary ion beam source system for use with embodiments of this disclosure is illustrated.

[0020] Figure 4B The diagram shows... Figure 4A The exemplary ion source depicted in the document.

[0021] Figure 5A An exemplary desired steady-state emission pulse for use with an ion beam source in accordance with embodiments of the present disclosure is illustrated.

[0022] Figure 5B The illustration shows an exemplary undesired steady-state emission pulse from an ion beam source.

[0023] Figure 6A An exemplary desired capacitive discharge profile for use with embodiments of this disclosure is illustrated.

[0024] Figure 6B An exemplary desired current pulse curve for use with embodiments of this disclosure is illustrated.

[0025] Figure 7 This is a timing diagram of an exemplary bias scheme for use with embodiments of this disclosure.

[0026] Figure 8 The illustration shows a block diagram of a system in which embodiments of the present disclosure may operate.

[0027] Figure 9 An exemplary computing device that can be specifically configured according to embodiments of the present disclosure is illustrated. Detailed Implementation

[0028] Before describing this subject matter in detail, it will be understood that this disclosure is not limited to the specific embodiments described, as these are of course subject to variation. It will also be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting, as the scope of this disclosure will be limited only by the appended claims.

[0029] The term “particle” is used extensively throughout this document and, unless otherwise limited, can be used to describe electrons, protons (or H+ ions) or neutrons, as well as matter having more than one electron, proton and / or neutron (e.g., other ions, atoms and molecules).

[0030] Exemplary embodiments of systems, apparatuses, and methods are described herein as beam source systems for use with beam systems (e.g., including particle accelerators). The embodiments described herein can be used with any type of particle accelerator or for any particle accelerator application involving generating a charged particle beam at a specified energy to supply to a particle accelerator.

[0031] Embodiments of the ion beam source system disclosed herein are particularly suitable for supplying ion beams, such as negative particle beams, to tandem accelerators that also work in conjunction with pre-accelerator systems. Such systems can be used in a variety of applications, one example being as a neutron beam system for generating neutron beams for boron neutron capture therapy (BNCT). For ease of description, many of the embodiments described herein are done in the context of a neutron beam system for BNCT, although these embodiments are not limited to neutron beam or BNCT applications.

[0032] The embodiments described herein reduce the average beam power of particle accelerator systems, enabling the provision of proton beams with parameters suitable for hyperthermal neutron sources for boron neutron capture therapy (BNCT) with lithium (Li) or beryllium (Be) targets. That is, the embodiments of this disclosure overcome several drawbacks associated with limitations introduced by the equipment and safety in the context of neutron beam systems. Proton beams provided by tandem accelerators for the purposes of boron neutron capture therapy (BNCT) have preferred energy levels for both therapeutic efficacy and use by downstream devices (e.g., for efficient neutron production on lithium (Li) targets). For example, the proton beam may preferably have an energy of 1.9–3.0 MeV. For reasonably short treatment times, specific flux density thresholds are required, and with such desired thresholds arises a minimum proton beam current (e.g., above 5 mA). The power density associated with such proton beams (e.g., proton beams with energies of 1.9–3.0 MeV and currents above 5 mA) far exceeds the safety limits of materials used in components of neutron beam systems (e.g., neutron generating targets, etc.).

[0033] For another example, with an exemplary nominal setting of 2.5 MeV beam energy and 10 mA beam current, the beam power is 25 kilowatts (kW). At such high power, it is important to avoid situations where the beam may become misaligned. For a proton beam focused to a location with a diameter less than 10 millimeters (mm) and a power rate exceeding 10 kW, the power density may significantly exceed the safety limits of the materials used in the tandem accelerator (and the entire neutron beam system). Any slight deflection of the beam could cause it to come into contact with (e.g., within the tandem accelerator) beam channel elements and almost immediately damage them, and the beam could potentially destroy these elements.

[0034] Advantageously, embodiments of this disclosure enable modulation of the negative ion beam at the ion beam source by modulating the ion extraction voltage. This modulation results in a limited pulse duration of the negative ion beam, reducing the average beam power to a safe level for the beam system materials, while providing a detectable steady-state ion beam to the tandem accelerator without affecting the voltage stability of the tandem accelerator. Therefore, a proton beam with the necessary beam energy and current is provided to downstream components without negatively impacting components of the overall neutron beam system (e.g., beam durations of 10 ms to 100 ms could damage the neutron generation target downstream of the tandem accelerator).

[0035] The desired pulse duration of the negative ion beam (e.g., how long the extraction electrodes of the ion beam source should be biased) can be based on many factors. While embodiments may vary, it is generally desirable that the pulse duration (1) be long enough to achieve steady-state extraction of negative hydrogen ions (H+) from the plasma of the ion source. - (1) and (2) short enough to avoid interference with the voltage regulation system of the tandem accelerator. In some embodiments, the pulse duration is short enough to avoid a total discharge of more than 10-15% of the capacitors in the tandem accelerator, and more preferably more than 5-6%. Thus, the energy stability of the beam passing through the tandem accelerator is maintained while protecting the equipment.

[0036] Regarding the pulse (1) being sufficiently long as described above, in some embodiments, for non-cesium (e.g., cesium-free (Cs)) ion sources, the time to reach a steady-state extraction of negative hydrogen ions is 0.1–0.3 ms. In some embodiments, the tandem accelerator has capacitors mounted in the outputs of various parts of the high-voltage rectifier. Regarding the pulse (2) being sufficiently short as described above, in such embodiments, when the tandem accelerator is at a nominal 2.5 MeV beam particle energy, the discharge capacitance through the beam propagation with a current of 10 mA and a duration of 1 ms preferably does not exceed 6%.

[0037] The specific embodiments described herein achieve a desired pulse duration of 0.5–1.0 ms, or a duty cycle of 0.5–1%, at a frequency of 10 Hz. The duty cycle (active time / total period) will vary depending on the operating parameters of the implemented beam system. For example, the duty cycle may range from 0.1% to 10%. In some embodiments, the duty cycle is 1% or less; in other embodiments, it is 2% or less; in still other embodiments, it is 5% or less; and in yet another embodiment, it is 10% or less.

[0038] Preferably, this beam modulation: (a) does not significantly interfere with the voltage stability of the tandem accelerator; (b) does not cause the capacitors within the tandem accelerator to discharge beyond a threshold amount (e.g., 15% or less); (c) provides a beam with a constant maximum output value (e.g., a flat or substantially flat top) for a threshold time amount (e.g., 2 ms), which is long enough for the typical time resolution of most beam diagnostics; and (d) significantly reduces the average beam power to a level safe for most materials used in the beam system compared to an unmodulated beam. In some embodiments, this reduction can be approximately 100 times (approximately 250 watts (W)). In addition to maintaining the functionality of the beam system, beam modulation according to the embodiments described herein results in longer-term integrity and reliability of the beam system materials and components.

[0039] Example BNCT application

[0040] Please see the attached image for details. Figure 1A This is a schematic diagram of an exemplary embodiment of a beam system 10 for use with embodiments of the present disclosure. Figure 1A In this system, beam system 10 includes a source 12, a low-energy beamline (LEBL) 14, an accelerator 16 coupled to the LEBL 14, and a high-energy beamline (HEBL) 16 extending from the accelerator 16 to a target 100. The LEBL 14 is configured to deliver a beam from the source 12 to the input of the accelerator 16, which is in turn configured to generate a beam by accelerating the beam delivered by the LEBL 14. The HEBL 18 transfers the beam from the output of the accelerator 16 to the target 100. The target 100 may be a structure configured to produce a desired result in response to a stimulus applied by the incident beam, or it may be capable of altering the properties of the beam. The target 100 may be a component of system 10 or may be a workpiece at least partially regulated or manufactured by system 10.

[0041] Figure 1BThis is a schematic diagram illustrating another exemplary embodiment of a neutron beam system 10 for boron neutron capture therapy (BNCT). Here, source 12 is an ion source and accelerator 16 is a tandem accelerator. The neutron beam system 10 includes a pre-accelerator system 20 serving as a charged particle beam injector, a high-voltage (HV) tandem accelerator 16 coupled to the pre-accelerator system 20, and an HEBL 18 extending from the tandem accelerator 16 to a neutron target assembly 200 housing a target 100 (not shown). In this embodiment, the target 100 is configured to produce neutrons in response to a bombardment of protons with sufficient energy and may be referred to as a neutron-generating target. The neutron beam system 10 and the pre-accelerator system 20 may also be used in other applications, such as those other examples described herein, and are not limited to BNCT.

[0042] The pre-accelerator system 20 is configured to deliver an ion beam from the ion source 12 to the input (e.g., the input aperture) of the tandem accelerator 16, thus also acting as the LEBL 14. Powered by a high-voltage power supply 42 coupled thereto, the tandem accelerator 16 produces a proton beam with energy typically equal to twice the voltage applied to the accelerating electrodes positioned within the accelerator 16. This proton beam energy level can be achieved by accelerating the innermost high-potential electrodes from the negative hydrogen ion beam at the input of the accelerator 16, stripping two electrons from each ion, and then accelerating the resulting protons downstream with the same applied voltage.

[0043] HEBL 18 delivers a proton beam from the output of accelerator 16 to a target within neutron target assembly 200, which is positioned at the end of a branch 70 of a beamline extending into a patient treatment chamber. System 10 can be configured to guide the proton beam to any number of targets and associated treatment areas within one or more targets. In this embodiment, HEBL 18 includes three branches 70, 80, and 90 that can extend into three different patient treatment chambers, each terminating in the target assembly 200 and a downstream beam shaping device (not shown). HEBL 18 may include a pump chamber 51, quadrupole magnets 52 and 72 to prevent beam defocusing, dipole or bending magnets 56 and 58 to guide the beam into the treatment chamber, a beam corrector 53, diagnostic devices such as current monitors 54 and 76, a fast beam position monitor section 55, and a scanning magnet 74.

[0044] The design of HEBL 18 depends on the construction of the processing facility (e.g., a single-layer construction, a two-layer construction, etc.). A bending magnet 56 can be used to deliver the beam to the target assembly (e.g., positioned near the treatment chamber) 200. A quadrupole magnet 72 can be included to subsequently focus the beam to a specific dimension at the target. The beam is then passed through one or more scanning magnets 74, which causes the beam to move laterally across the target surface in a desired pattern (e.g., spirals, bends, staircases in rows and columns, combinations thereof, etc.). Lateral beam movement helps achieve a smooth and uniform temporal distribution of the proton beam on the lithium target, thereby preventing overheating and ensuring that neutron generation within the lithium layer is as uniform as possible.

[0045] After entering the scanning magnet 74, the beam can be transmitted to a current monitor 76 for measuring the beam current. A gate valve 77 can be used to physically separate the target assembly 200 from the HEBL volume. The primary function of the gate valve is to separate the vacuum volume of the beamline from the target when loading the target and / or replacing a used target with a new one. In this embodiment, the beam cannot be bent 90 degrees by the magnet 56, but is instead directed directly towards... Figure 1B The beam travels to the right and then enters a quadrupole magnet 52 located in the horizontal beam. The beam can then be bent to the desired angle by another bending magnet 58, depending on the building and room construction. Alternatively, the bending magnet 58 can be replaced with a Y-shaped magnet to split the beam in two directions for two different treatment rooms located on the same floor.

[0046] Figure 2 An example of a pre-accelerator system or ion beam implanter used with embodiments of this disclosure is shown. In this example, the pre-accelerator system 20 (e.g., LEBL 14) includes a single lens 30 (in... Figure 2 Invisible in the middle, but in Figures 3A-3B The system comprises a pre-accelerator tube 26 and a solenoid 510, and is configured to accelerate a negative ion beam injected from the ion source 12. The pre-accelerator system 20 is configured to provide the energy required to accelerate the beam particles to the tandem accelerator 16 and to provide overall focusing of the negative ion beam to match the inlet aperture or inlet area of ​​the tandem accelerator 16. The pre-accelerator system 20 is also configured to minimize backflow or defocusing backflow when recirculating from the tandem accelerator 16 through the pre-accelerator system, thereby reducing the possibility of damage to the ion source 12 and / or backflow to the filament of the ion source.

[0047] In one embodiment, the ion source 12 may be configured to provide a negative ion beam upstream of the single lens 30, and the negative ion beam continues through the pre-accelerator tube 26 and the magnetic focusing device (e.g., a solenoid) 510. The solenoid 510 may be positioned between the pre-accelerator tube 26 and the tandem accelerator 16 and may be electrically connected to a power source. The negative ion beam reaches the tandem accelerator 16 through the solenoid 510.

[0048] The pre-accelerator system 20 may also include an ion source vacuum chamber 24 for gas removal and a pump chamber 28, the pump chamber 28 being part of a relatively low-energy beamline leading to the tandem accelerator 16, along with the pre-accelerator tube 26 and the other aforementioned components. A single lens 30 may be positioned within the ion source vacuum chamber 24, which extends from the ion source 12. The pre-accelerator tube 26 may be coupled to the ion source vacuum chamber 24 and the solenoid 510. The vacuum pump chamber 28 for gas removal may be coupled to the solenoid 510 and the tandem accelerator 16. The ion source 12 serves as a source of charged particles that, when conveyed to a neutron generator, can be accelerated, tuned, and ultimately used to generate a neutron target. Exemplary embodiments will be described herein with reference to an ion source that generates a negative hydrogen ion beam, but the embodiments are not limited thereto, and the source may generate other positive or negative particles.

[0049] The pre-accelerator system 20 may have zero or one or more magnetic elements for purposes such as focusing and / or adjusting beam alignment. For example, any such magnetic element may be used to match the beam to the beamline axis and the receiving angle of the tandem accelerator 16. The ion vacuum chamber 24 may have ion optics positioned therein.

[0050] Negative ion sources 12 are generally of two types based on their mechanisms of negative ion generation: surface-type and volumetric-type. Surface-type sources typically require the presence of cesium (Cs) on a specific inner surface. Volumetric-type sources rely on the formation of negative ions within a volume of high-current discharge plasma. While both types of ion sources can deliver the required negative ion current for applications associated with tandem accelerators, surface-type negative ion sources are not suitable for modulation. That is, for the modulation of the negative ion beam in the embodiments described herein, a volumetric negative ion source (e.g., without cesium (Cs)) is preferred.

[0051] Steering Figure 3A The ion source vacuum chamber 24 of the ion beam implanter 20 includes a single lens 30 positioned therein. For example... Figure 3B As shown in detail, the single lens 30 downstream of the grounding lens 25 of the ion source 12, installed within the vacuum chamber 24, includes a mounting plate 32, two grounding electrodes 34 coupled to each other and spaced apart from each other by a mounting rod 35, and a energized (biased) electrode 38 positioned between the two grounding electrodes 34. Electrodes 34 and 38 are in the form of cylindrical apertures and assembled to have an axial axis coinciding with the beam path. The energized electrode 38 is supported by an insulator / isolator 36 extending between the grounding electrodes or the aperture 34.

[0052] The support isolator 36 may include a geometry configured to prevent the development of electron avalanche and suppress streamer formation and propagation, which typically ends in flashover formation. The geometry of the support isolator 36 can partially shield external electric fields on the insulator surface driving electron avalanche and effectively increase path length. Additionally, the material of the insulator / isolator 36 tends to reduce sputtering effects, loss of negative ions on the surface, volume contamination, and the formation of conductive coatings on the insulator / isolator surface that lead to reduced electrical strength.

[0053] Functionally, the single lens 30 acts on the beam of charged particles advancing from the ion source 12 in a manner similar to that of an optical focusing lens. That is, the single lens 30 focuses the incident parallel beam onto a point on the focal plane. However, the electric field formed here between the paired energized electrodes 38 and the two grounded electrodes 34 determines the focusing intensity (focal length) of the single lens.

[0054] By mounting the single lens 30 downstream of the ion source grounding lens 25, it reduces beam free space transport, where the beam diverges due to inherent space charge.

[0055] The dimensions of the axisymmetric design of the single lens 30 are optimized to avoid direct interaction between the extracted ions and the exposed surface of the single lens 30.

[0056] In operation, the negative polarity bias of the single lens 30 results in a higher focusing capability than a positive polarity bias. Also in operation, the method of powering the single lens 30 provides a gradual voltage increase rather than an instantaneous voltage application, which reduces the electric field growth rate (dE / dt) present on the surface of the single lens 30 at micro-protrusions that could form plasma via, for example, an explosive emission mechanism. Preventing the formation of such plasma improves electrical strength.

[0057] Due to electrical breakdown, a negative bias potential for a single lens under high background pressure is typically impossible. The exemplary configuration of the single lens provided herein enables the application of a sufficiently high negative bias voltage to achieve 100% current utilization without electrical breakdown.

[0058] Figure 4A An exemplary ion beam source system for use with embodiments of this disclosure is shown. Figure 4A Optionally, the ion source 12 is housed within an ion source enclosure. The ion source 12 includes multiple electrodes, such as a plasma electrode 320, an accelerator / accelerating electrode (e.g., or a grounding lens) 310, and an extraction electrode 330. Optionally, the ion source 12 is coupled to a single lens 30, and a negative ion beam is injected or propagated from the ion source 12 through the single lens 30, the pre-accelerator tube 26, and the solenoid 510 to the input aperture of the tandem accelerator 16.

[0059] Reference Figure 4B The ion source 12 can be electrically connected at the accelerator electrode 310 to a first terminal of the power supply PS3, which is in turn electrically connected at a second terminal to the enclosure of the ion source 12. The biasing of the ion source 12 at the accelerator electrode 310 configures the pre-accelerator system 20 to maintain and pass through the negative ion beam as it arrives from the ion source 12. In some embodiments, the power supply PS3 can provide a voltage of -30 kV.

[0060] The plasma electrode 320 of the ion source 12 can be electrically connected to the power supply PS5, and the extraction electrode 330 of the ion source 12 can be electrically connected to the modulator 350, which in turn is electrically connected to the power supply PS4. When the extraction electrode 330 is biased, the bias of the plasma electrode 320 enables the ion source 12 to maintain the plasma within the ion source 12 for extraction into a negative ion beam.

[0061] In some embodiments, the modulator 350 and the power supply PS4 can be combined within a single integrated regulator system. The modulator 350 includes a switch that can be used to control the bias of the lead-out electrode 330.

[0062] When the extraction electrode 330 is biased, the negative ion beam is transmitted or propagated from the ion source 12 to the tandem accelerator 16. When the extraction electrode 330 is not biased, the negative ion beam is not transmitted or propagated from the ion source 12 to the tandem accelerator 16.

[0063] As described above, the tandem accelerator 16 is powered by a high-voltage power supply 42 coupled thereto and can produce a proton beam with energy typically equal to twice the voltage applied to accelerating electrodes positioned within the accelerator 16. The tandem accelerator 16 may include any number of nested shells of two or more nested shells, with accelerating electrodes located at the leftmost and rightmost apertures of each shell, such as... Figure 4AAs shown. In this embodiment, accelerator 16 includes four housings G1, G2, G3, G4 plus the innermost housing labeled as the high-voltage (HV) chamber. Power supply PS6 can be controlled by a feedback loop to maintain voltage stability within the tandem accelerator 16. That is, a measuring or control device 360 ​​(e.g., a voltmeter) can monitor the voltage across capacitors (C) installed at the outputs of various portions of the high-voltage rectifier in the tandem accelerator 16. At least one capacitor can be connected between each housing and the housing immediately adjacent to it. In this example, four capacitors are connected across five housings. Operation of the beam through accelerator 16 can cause the capacitors to discharge. Voltage stability indicates that the capacitor discharge does not exceed a threshold of a fully charged state to maintain the stability of beam 620. In some embodiments, this threshold is 5%; in others, it is 6%; in still others, it is 10%; and in yet another embodiment, it is 15%. In such an example, the measuring or control device 360 ​​may provide a feedback signal indicating voltage instability to the power supply PS6, and the power supply PS6 may stop biasing the tandem accelerator 16.

[0064] Figure 5A An exemplary desired steady-state emission pulse for use with an ion beam source in accordance with embodiments of the present disclosure is shown. Figure 5B An exemplary undesired steady-state emission pulse from an ion beam source is shown. Figure 5A The diagram illustrates how the biasing of the extraction electrode at the ion beam source causes negative hydrogen ions to be extracted from the steady state of the plasma in the ion source within a short period of time; otherwise, the generation of the ion beam might not be successful within the window required to protect downstream components. Figure 5B The unexpected steep ascent to steady state is described.

[0065] Figure 6A An exemplary capacitor discharge curve is shown for use with embodiments of this disclosure. Figure 6B An exemplary desired current pulse profile for use with embodiments of this disclosure is shown. The desired ion beam pulse current characteristics resemble an ideal step function, such as... Figure 6B The figure shows constant values ​​with minimal rise and fall slopes and effective pulse duration, resulting in... Figure 6A The capacitor discharge curves shown indicate that modulation does not cause the capacitor discharge to exceed a threshold (e.g., in some embodiments, this threshold may be approximately 5-6%). As described above, limiting the pulse duration of the negative ion beam 600 by the modulation system, which controls the bias (or non-biasing) of the extraction electrodes 330 of the ion source 12, reduces the likelihood that multiple capacitors will discharge beyond 5-6%, thereby reducing (or completely eliminating) the possibility of power supply PS6 interrupting the power supply to the tandem accelerator 16.

[0066] The capacitance ratings of multiple capacitors can help limit the duration of a successful beam pulse. That is, the larger the capacitor, the longer the beam pulse duration may be, but space and other design constraints result in a lack of flexibility when increasing capacitance across various beam systems.

[0067] Figure 7 This is a timing diagram illustrating examples of various parameters that have a time relationship with each other for use with embodiments of this disclosure. Figure 7 In the topmost graph, for a given duration from t1 to t3 (e.g., t...), 脉冲 Apply an extraction bias (e.g., U) 引出 This forms an extraction pulse 700 that results in an extraction beam from the particle source. As shown here, the extraction bias is applied in the shape of a step function or a square wave; however, this is an idealized description and those skilled in the art will recognize that some deviations will occur. The current of the extraction beam (I...) 束 The current I is depicted in the middle of the diagram. 束 The bias U is responded to by rapidly increasing the magnitude from t1 until it reaches a constant or substantially constant value at t2. 引出 This is depicted by the uppermost contour 702 of the flat or substantially flat current pulse. This region of stable amplitude can be referred to as the steady state of the current, and it lasts for a period of time (e.g., t). 平坦顶部 The bias is removed at time t3, until the bias is removed at time t2. In some embodiments, the steady-state duration from time t2 to t3 (e.g., t...) 平坦顶部 It is long enough to obtain one or more measurements associated with the beam system.

[0068] Before beam extraction (e.g., from t0 to t1), the accelerator voltage U 串列 Charged to a steady-state level of 704. (Refer to...) Figure 4A In embodiments of the described tandem accelerator 16, the steady-state level can be a full charge of the capacitors (C) between the individual accelerating electrodes. These capacitors discharge when the ion beam is extracted from the ion source at t1. In these embodiments, the discharge is preferably maintained within a discharge threshold ΔU (e.g., 15% or less, 10% or less, 6% or less). In some embodiments, the modulation system may be set or programmed such that t 脉冲 The duration is the length of time that the discharge level is maintained within the threshold ΔU. In some embodiments, t 脉冲 The duration can be controlled by a feedback loop, such that the discharge quantity is actively monitored by the modulation system (or by the control system described herein) and a pulse is drawn before the discharge quantity exceeds the discharge threshold ΔU (or conversely, before U). 串列The discharge pulse 700 terminates at t3 before the discharge threshold ΔU is reached. When the extraction pulse 700 terminates at t3 so that no more ion beams are extracted from the exemplary ion source, the charge on the capacitor (e.g., U) is released. 串列 The capacitor returns to nominal level 704. In an embodiment, the minimum period (e.g., t1 to t4) of the charging pulse is sufficient to exceed the duration required to charge the capacitor back to level 704.

[0069] Figure 8 This is a block diagram illustrating an exemplary system in which embodiments of the present disclosure may operate. For example, the illustrated exemplary system includes an ion beam source system 3001, one or more computing devices 3002, and a tandem accelerator system 3003. In embodiments, the ion beam source system 3001 and the tandem accelerator system 3003 may collectively be part of an exemplary neutron beam system (e.g., system 10 above). In such embodiments, the neutron beam system 10 may employ one or more control systems with which one or more computing devices 3002 can communicate to interact with the system and components of the neutron beam system 10. Each of these devices and / or systems is configured to communicate directly with each other (not shown) or via a local network (e.g., network 3004).

[0070] The computing device 3002 may be embodied in various user devices, systems, computing devices, etc. For example, a first computing device 3002 may be a desktop computer associated with a specific user, another computing device 3002 may be a laptop computer associated with a specific user, and yet another computing device 3002 may be a mobile device (e.g., a tablet or smart device). Each of the computing devices 3002 may be configured to communicate with the ion beam source system 3001 and / or the tandem accelerator system 3003, for example, through a user interface accessible via the computing device. For example, a user may execute a desktop application on the computing device 3002, which is configured to communicate with the ion beam source system 3001 and / or the tandem accelerator system 3003.

[0071] By communicating with one or more of the ion beam source system 3001 or the tandem accelerator system 3003 using the computing device 3002, a user can provide operating parameters (e.g., operating voltage, etc.) for either system according to the embodiments described herein. In an embodiment, the ion beam source system 3001 may include a control system 3001A, through which the ion beam source system 3001 receives and applies operating parameters from the computing device 3002. In an embodiment, the tandem accelerator system 3003 may include a control system 3003A, through which the tandem accelerator system 3003 can receive and apply operating parameters from the computing device 3002.

[0072] The communication network 3004 may include any wired or wireless communication network, such as a wired or wireless local area network (LAN), personal area network (PAN), metropolitan area network (MAN), wide area network (WAN), etc., and any hardware, software, and / or firmware required to implement it (e.g., network routers, etc.). For example, the communication network 3004 may include 802.11, 802.16, 802.20, and / or WiMax networks. Furthermore, the communication network 3004 may include public networks such as the Internet, private networks such as intranets, or combinations thereof, and may utilize various networking protocols now available or developed in the future, including but not limited to TCP / IP based on networking protocols.

[0073] The computing device 3002 and the control systems 3001A and 3003A may be embodied by one or more computing systems, for example Figure 9 The device shown is 3100. (As shown) Figure 9 As shown, device 3100 may include processor 3102, memory 3104, input and / or output circuitry 3106, and communication means or circuitry 3108. It should also be understood that some of these components 3102-3108 may include similar hardware. For example, two modules may leverage the same processor, network interface, storage medium, etc., to perform their associated functions, thus avoiding the need for duplicate hardware for each device. Therefore, the use of the terms "means" and / or "circuitry" as used herein with respect to components of a device may encompass specific hardware configured with software to perform functions associated with that particular device, as described herein.

[0074] The terms "device" and / or "circuit" should be broadly understood to include hardware, and in some embodiments, the device and / or circuit may also include software for configuring the hardware. For example, in some embodiments, the device and / or circuit may include processing circuitry, storage media, network interfaces, input / output devices, etc. In some embodiments, other elements of the device 3100 may provide or supplement the functionality of a particular device. For example, the processor 3102 may provide processing functionality, the memory 3104 may provide storage functionality, the communication device or circuit 3108 may provide network interface functionality, and so on.

[0075] In some embodiments, processor 3102 (and / or coprocessor or auxiliary processor or any other processing circuitry otherwise associated with the processor) may communicate with memory 3104 via a bus to transfer information between components of the device. Memory 3104 may be non-transitory and may include, for example, one or more volatile and / or non-volatile memories. In other words, for example, memory may be an electronic storage device (e.g., a computer-readable storage medium). Memory 3104 may be configured to store information, data, content, applications, instructions, etc., to enable the device to perform various functions according to exemplary embodiments of the present disclosure.

[0076] The processor 3102 may be embodied in a variety of different ways and may, for example, include one or more processing devices configured to operate independently. Additionally or alternatively, the processor may include one or more processors configured in series via a bus to enable independent execution of instructions, pipelining, and / or multithreading. The use of the terms "processing device" and / or "processing circuitry" is to be understood to include single-core processors, multi-core processors, multiple processors within a device, and / or remote or "cloud" processors.

[0077] In one exemplary embodiment, processor 3102 may be configured to execute instructions stored in memory 3104 or accessible to the processor. Alternatively or additionally, the processor may be configured to perform hard-coded functions. Thus, whether configured by hardware or software methods, or by a combination of hardware and software, the processor may represent an entity (e.g., physically embodied in circuitry) capable of performing operations according to embodiments of this disclosure simultaneously in a given configuration. Alternatively, as another example, when the processor is embodied as an executor of software instructions, the instructions may specifically configure the processor to perform the algorithms and / or operations described herein when the instructions are executed.

[0078] In some embodiments, device 3100 may include an input / output device 3106, which may communicate with processor 3102 to provide output to a user and, in some embodiments, receive input from the user. Input / output device 3106 may include a user interface and may include a device display, such as a user device display that may include a web user interface, mobile application, client device, etc. In some embodiments, input / output device 3106 may also include a keyboard, mouse, joystick, touchscreen, touch area, softkeys, microphone, speaker, or other input / output mechanism. The processor and / or user interface circuitry including the processor may be configured to control one or more functions of one or more user interface elements via computer program instructions (e.g., software and / or firmware) stored in processor-accessible memory (e.g., memory 3104, etc.).

[0079] The communication device or circuit 3108 can be any device, such as device circuitry embodied in hardware or a combination of hardware and software, configured to receive and / or transmit data from / to a network and / or any other device or circuitry communicating with device 3100. In this regard, the communication device or circuit 3108 may include, for example, a network interface for enabling communication with wired or wireless communication networks. For example, the communication device or circuit 3108 may include one or more network interface cards, antennas, buses, switches, routers, modems, and supporting hardware and / or software, or any other means suitable for enabling communication via a network. Additionally or alternatively, the communication interface may include circuitry for interacting with an antenna to induce the transmission of signals via the antenna or for processing signals received via the antenna. These signals may be transmitted by device 3100 using any of a variety of wireless personal area network (PAN) technologies, such as current and future Bluetooth standards (including Bluetooth and Bluetooth Low Energy (BLE)), infrared wireless (e.g., IrDA), FREC, ultra-wideband (UWB), inductive wireless generation, etc. Additionally, it should be understood that these signals can be transmitted using Wi-Fi, Near Field Communication (NFC), Global Microwave Access Interoperability (WiMAX), or other short-range-based communication protocols.

[0080] It should be understood that any such computer program instructions and / or other type of code can be loaded onto the circuitry of a computer, processor, or other programmable device to produce a machine, such that the computer, processor, or other programmable circuitry executing the code on the machine creates means to implement a variety of functions—including those described herein.

[0081] As will be understood from the above and based on this disclosure, embodiments of this disclosure can be configured as systems, methods, mobile devices, backend network devices, etc. Therefore, embodiments can include various implementations, including entirely hardware or any combination of software and hardware. Furthermore, embodiments can take the form of a computer program product on at least one non-transitory computer-readable storage medium having computer-readable program instructions (e.g., computer software) embodied in the storage medium. Any suitable computer-readable storage medium can be used, including non-transitory hard disks, CD-ROMs, flash memory, optical storage devices, or magnetic storage devices.

[0082] Processing circuitry used in conjunction with embodiments of the present disclosure may include one or more processors, microprocessors, controllers, and / or microcontrollers, each of which may be discrete chips or distributed across multiple different chips (and portions thereof). Processing circuitry used in conjunction with embodiments of the present disclosure may include a digital signal processor, which may be implemented in the hardware and / or software of the processing circuitry used in conjunction with embodiments of the present disclosure. Processing circuitry used in conjunction with embodiments of the present disclosure may be communicatively coupled to other components of the accompanying drawings. Processing circuitry used in conjunction with embodiments of the present disclosure may execute software instructions stored in memory that cause the processing circuitry to take a variety of different actions and control other components of the accompanying drawings.

[0083] Memory used in conjunction with embodiments of this disclosure may be shared by one or more of various functional units, or may be distributed among two or more of them (e.g., as separate memory located within different chips). The memory itself may also be a separate chip. The memory may be non-transitory and may be volatile memory (e.g., RAM, etc.) and / or non-volatile memory (e.g., ROM, flash memory, F-RAM, etc.).

[0084] Computer program instructions that perform operations according to the described subject can be written in any combination of one or more programming languages, including object-oriented programming languages ​​such as Java, JavaScript, Smalltalk, C++, C#, Transact-SQL, XML, PHP, etc., as well as traditional procedural programming languages ​​such as the "C" programming language or similar programming languages.

[0085] The following review and / or supplementation of the embodiments described to date illustrates various aspects of this subject matter, with emphasis placed on the interrelationships and interchangeability of the following embodiments. In other words, emphasis is placed on the fact that each feature of the embodiments can be combined with every other feature, unless expressly stated otherwise or logically implausible.

[0086] In many embodiments, the ion beam system includes an ion source configured to provide a negative ion beam to a tandem accelerator system downstream of the ion source and a modulator system connected to an extraction electrode of the ion source. In many of these embodiments, the modulator system is configured to bias the extraction electrode for a duration sufficient to achieve steady-state ion extraction and maintain the acceleration voltage stability of the tandem accelerator system.

[0087] In many of these embodiments, the ion source is configured to generate negative hydrogen ions.

[0088] In many of these embodiments, the duration is less than 10 milliseconds (ms). In many of these embodiments, the duration is in the range of 0.5 to 1.0 milliseconds (ms).

[0089] In many of these embodiments, the modulator system includes a switch. In many of these embodiments, the modulator system includes a DC power supply.

[0090] In many of these embodiments, the acceleration voltage stability is partly based on capacitive discharge associated with multiple capacitors in the tandem accelerator system.

[0091] In many of these embodiments, one or more electrodes of the tandem accelerator system are biased using a DC power supply. In many of these embodiments, the DC power supply responds to the feedback loop based on capacitive discharge associated with multiple capacitors within the tandem accelerator system. In many of these embodiments, the DC power supply includes an ultra-low voltage (ELV) DC power supply. In many of these embodiments, the duration is shorter than the response time of the feedback loop.

[0092] In many of these embodiments, the ion source includes an accelerating electrode. In many of these embodiments, the accelerating electrode is continuously biased using a first power supply.

[0093] In many of these embodiments, the ion source includes a plasma electrode. In many of these embodiments, the plasma electrode is continuously biased using a second power supply.

[0094] In many of these embodiments, the first power supply, second power supply, and third power supply of the modulator system are independent of each other.

[0095] In many of these embodiments, the negative ion beam passes through a pre-accelerator system downstream of the ion beam source system before reaching the tandem accelerator system. In many of these embodiments, the duration is short enough to avoid beam-induced damage to components of the pre-accelerator system or the tandem accelerator system.

[0096] In many of these embodiments, the duration is sufficient to provide a proton beam with a beam energy of 2.5 MeV.

[0097] In many of these embodiments, the duration is sufficient to cause less than 15% capacitive discharge within the tandem accelerator system due to the introduction of a negative ion beam.

[0098] In many of these embodiments, the duration is sufficient to cause less than 6% capacitive discharge within the tandem accelerator system due to the introduction of a negative ion beam.

[0099] In many of these embodiments, the duration is long enough to achieve steady-state ion extraction from the ion source. In many of these embodiments, the steady-state ion extraction ramp-up time from the ion source is 0.1–0.3 milliseconds (ms).

[0100] In many of these embodiments, the tandem accelerator system includes multiple input electrodes, a charge exchange device, and multiple output electrodes. In many of these embodiments, the multiple input electrodes are configured to accelerate a negative ion beam from a pre-accelerator system, the charge exchange device is configured to convert the negative ion beam into a positive beam, and the multiple output electrodes are configured to accelerate the positive beam. In many of these embodiments, a target device downstream of the tandem accelerator system is configured to form a neutral beam from the positive beam received from the tandem accelerator system. In many of these embodiments, the duration is short enough to avoid beam damage to the target device.

[0101] In many embodiments, the beam modulation method includes biasing the extraction electrodes of an ion source to a duration sufficient to maintain the acceleration voltage stability of the tandem accelerator system, the ion source being configured to provide a negative ion beam to the tandem accelerator system.

[0102] In many of these embodiments, the ion source is configured to generate negative hydrogen ions.

[0103] In many of these embodiments, the method includes biasing the lead electrode for less than 10 milliseconds (ms). In many of these embodiments, the method includes biasing the lead electrode for between 0.5 and 1 millisecond (ms).

[0104] In many of these embodiments, the method includes measuring acceleration voltage stability in part based on capacitive discharge associated with multiple capacitors in a tandem accelerator system.

[0105] In many of these embodiments, the method includes biasing one or more electrodes of the tandem accelerator system using a DC power supply.

[0106] In many of these embodiments, the DC power supply responds to the feedback loop based on capacitive discharge associated with multiple capacitors within the tandem accelerator system.

[0107] In many of these embodiments, the method includes biasing the lead-out electrode for a duration less than the response time of the feedback loop.

[0108] In many of these embodiments, the ion source includes an accelerating electrode. In many of these embodiments, the method includes continuously biasing the accelerating electrode using a first power supply.

[0109] In many of these embodiments, the ion source includes a plasma electrode. In many of these embodiments, the method includes continuously biasing the plasma electrode using a second power supply.

[0110] In many of these embodiments, the negative ion beam passes through a pre-accelerator system downstream of the ion source before reaching the tandem accelerator system. In many of these embodiments, the duration is short enough to avoid beam-induced damage to components of the pre-accelerator system or the tandem accelerator system.

[0111] In many of these embodiments, the duration is sufficient to provide a proton beam with a beam energy of 2.5 MeV.

[0112] In many of these embodiments, the duration is sufficient to cause capacitive discharge of no more than 6% within the tandem accelerator system due to the introduction of a negative ion beam.

[0113] In many of these embodiments, the ion source includes a non-cesium ion source.

[0114] In many of these embodiments, the duration is long enough to achieve steady-state ion extraction from the ion source. In many of these embodiments, the steady-state ion extraction ramp-up time from the ion source is 0.1 milliseconds (ms) to 0.3 milliseconds (ms).

[0115] In many embodiments, the beam system includes: a source including an extraction electrode configured to generate a beam of charged particles; a modulator system connected to the extraction electrode of the source, wherein the modulator system is configured to modulate the beam of charged particles; and an accelerator configured to accelerate the modulated beam of charged particles.

[0116] In many of these embodiments, the modulator system is configured to modulate a beam of charged particles into multiple pulses. In many of these embodiments, each pulse has a duration sufficient to achieve steady-state particle extraction.

[0117] In many of these embodiments, the accelerator includes one or more capacitors. In many of these embodiments, the modulated beam does not cause one or more capacitors to discharge beyond a threshold amount. In many of these embodiments, the threshold amount is 15% or less of the full charge of one or more capacitors. In many of these embodiments, the threshold amount is 6% or less of the full charge of one or more capacitors.

[0118] In many of these embodiments, the duration is less than 10 milliseconds (ms) and the duty cycle is between 0.1% and 10%.

[0119] In many of these embodiments, the duration is in the range of 0.5 to 1.0 milliseconds (ms).

[0120] In many of these embodiments, the modulator system is configured to modulate the charged particle beam to maintain the acceleration voltage stability of the accelerator.

[0121] In many of these embodiments, the acceleration voltage stability is based at least in part on capacitive discharge associated with multiple capacitors of the accelerator.

[0122] In many of these embodiments, a DC power supply is used to bias one or more electrodes of the accelerator. In many of these embodiments, the DC power supply response is based on a feedback loop of capacitive discharge associated with multiple capacitors within the accelerator. In many of these embodiments, the duration is shorter than the response time of the feedback loop. In many of these embodiments, the accelerator is a tandem accelerator.

[0123] In many of these embodiments, the charged particle beam is a negative ion beam, the accelerator is configured to convert the negative ion beam into a proton beam, and each pulse has a duration sufficient to provide a proton beam with a beam energy between 1.9 and 3.0 MeV.

[0124] In many of these embodiments, the modulation system is configured to modulate the charged particle beam such that capacitive discharge within the accelerator does not exceed 15% during the acceleration of the modulated charged particle beam.

[0125] In many of these embodiments, the modulation system is configured to modulate the charged particle beam such that capacitive discharge within the accelerator does not exceed 6% during the acceleration of the modulated charged particle beam.

[0126] In many of these embodiments, the accelerator is a tandem accelerator, which includes a plurality of nested shells and one or more capacitors electrically connected between adjacent shells, and capacitive discharge is the discharge of the one or more capacitors.

[0127] In many of these embodiments, the accelerator is a tandem accelerator including multiple input electrodes, a charge exchange device, and multiple output electrodes. In many of these embodiments, the charged particle beam is a negative ion beam, and the tandem accelerator is configured to accelerate the negative ion beam using the multiple input electrodes, the charge exchange device is configured to convert the negative ion beam into a positive beam, and the tandem accelerator is configured to accelerate the positive beam using the multiple output electrodes. In many of these embodiments, the beam system includes a target device downstream of the tandem accelerator. In many of these embodiments, the target device is configured to form a neutral beam from the positive beam.

[0128] In many of these embodiments, the modulator system is configured to modulate the charged particle beam into multiple pulses. In many of these embodiments, each pulse has a finite duration to avoid thermal damage to the target device.

[0129] It should be noted that all features, elements, components, functions, and steps described with respect to any embodiments provided herein are intended to be freely combined and substituted with features, elements, components, functions, and steps from any other embodiment. If a feature, element, component, function, or step is described with respect to only one embodiment, it should be understood that such feature, element, component, function, or step may be used with every other embodiment described herein, unless expressly stated otherwise. Therefore, this paragraph serves at all times as the basis for reference and written support of the introduction of the claims, which combine features, elements, components, functions, and steps from different embodiments, or substitute features, elements, components, functions, and steps from one embodiment for features, elements, components, functions, and steps from another embodiment, even if such combinations or substitutions are not expressly stated in particular cases. It is expressly acknowledged that a detailed description of every possible combination and substitution would be overly cumbersome, especially considering that the permissibility of each such combination and substitution will be readily apparent to those skilled in the art.

[0130] In the sense that the embodiments disclosed herein include a memory, storage device, and / or computer-readable medium, or operate in conjunction with them, the memory, storage device, and / or computer-readable medium is non-transitory. Therefore, in the sense that the memory, storage device, and / or computer-readable medium is covered by one or more claims, the memory, storage device, and / or computer-readable medium is merely non-transitory.

[0131] As used herein and in the appended claims, the singular forms “a,” “an,” and “the” include plural references unless the context clearly specifies otherwise.

[0132] While the embodiments are readily available with various modifications and alternatives, specific examples have been shown in the accompanying drawings and described in detail herein. However, it should be understood that these embodiments are not limited to the specific forms disclosed, but rather, they will cover all modifications, equivalents, and alternatives falling within the spirit of this disclosure. Furthermore, any feature, function, step, or element of the embodiments may be recited in or added to the claims, as well as to the claims or such negative limitations that define the scope of the invention by features, functions, steps, or elements not within the scope of the claims.

Claims

1. An ion beam source system, comprising: An ion source configured to provide a negative ion beam to a tandem accelerator system downstream of the ion source; and A modulator system connected to the extraction electrode of the ion source, wherein the modulator system is configured to bias the extraction electrode for a duration sufficient to achieve steady-state ion extraction and maintain the acceleration voltage stability of the tandem accelerator system, wherein the duration is sufficient to cause less than 15% capacitive discharge within the tandem accelerator system due to the introduction of a negative ion beam.

2. The ion beam source system according to claim 1, wherein, The ion source is configured to generate negative hydrogen ions.

3. The ion beam source system according to claim 1, wherein, The duration is less than 10 milliseconds (ms).

4. The ion beam source system according to claim 1, wherein, The duration is in the range of 0.5 to 1.0 milliseconds (ms).

5. The ion beam source system according to claim 1, wherein, The modulator system includes a switch.

6. The ion beam source system according to claim 1, wherein, The modulator system includes a DC power supply.

7. The ion beam source system according to claim 1, wherein, The acceleration voltage stability is partly based on capacitive discharge associated with multiple capacitors in the tandem accelerator system.

8. The ion beam source system according to claim 1, wherein, One or more electrodes of the tandem accelerator system are biased using a DC power supply.

9. The ion beam source system according to claim 8, wherein, The DC power supply responds to the feedback loop based on capacitive discharge associated with multiple capacitors within the tandem accelerator system.

10. The ion beam source system according to claim 8, wherein, The DC power supply includes an ultra-low voltage (ELV) DC power supply.

11. The ion beam source system according to claim 9, wherein, The duration is less than the response time of the feedback loop.

12. The ion beam source system according to claim 1, wherein, The ion source includes an accelerating electrode.

13. The ion beam source system according to claim 12, wherein, The accelerating electrode is continuously biased using a first power supply.

14. The ion beam source system according to claim 1, wherein, The ion source includes a plasma electrode.

15. The ion beam source system according to claim 14, wherein, The plasma electrode is continuously biased using a second power source.

16. The ion beam source system according to claims 13 and 15, wherein, The first power supply, second power supply, and third power supply of the modulator system are independent of each other.

17. The ion beam source system according to claim 1, wherein, The negative ion beam passes through a pre-accelerator system downstream of the ion beam source system before reaching the tandem accelerator system.

18. The ion beam source system according to claim 17, wherein, The duration is short enough to avoid beam-induced damage to components of the pre-accelerator system or the tandem accelerator system.

19. The ion beam source system according to claim 1, wherein, The duration is sufficient to provide a proton beam with a beam energy of 2.5 MeV.

20. The ion beam source system according to claim 1, wherein, The duration is sufficient to cause less than 6% capacitive discharge within the tandem accelerator system due to the introduction of a negative ion beam.

21. The ion beam source system according to claim 1, wherein, The duration is long enough to allow for the extraction of steady-state ions from the ion source.

22. The ion beam source system according to claim 21, wherein, The steady-state ion extraction ramp-up time of the ion source is 0.1-0.3 milliseconds (ms).

23. The ion beam source system according to claim 1, wherein, The tandem accelerator system includes multiple input electrodes, charge exchange devices, and multiple output electrodes.

24. The ion beam source system according to claim 23, wherein, The plurality of input electrodes are configured to accelerate the negative ion beam from the pre-accelerator system, the charge exchange device is configured to convert the negative ion beam into a positive beam, and the plurality of output electrodes are configured to accelerate the positive beam.

25. The ion beam source system according to claim 24, wherein, The target device downstream of the tandem accelerator system is configured to form a neutral beam from the positive beam received from the tandem accelerator system.

26. The ion beam source system according to claim 25, wherein, The duration is short enough to avoid beam-induced damage to the target device.

27. A beam modulation method, comprising: The extraction electrode of the ion source is biased for a duration sufficient to maintain the acceleration voltage stability of the tandem accelerator system, the ion source being configured to provide a negative ion beam to the tandem accelerator system, wherein the duration is sufficient to cause less than 15% capacitive discharge to occur within the tandem accelerator system due to the introduction of the negative ion beam.

28. The method according to claim 27, wherein, The ion source is configured to generate negative hydrogen ions.

29. The method of claim 27, further comprising biasing the lead-out electrode for less than 10 milliseconds (ms).

30. The method of claim 27, further comprising biasing the lead-out electrode for 0.5 to 1 millisecond (ms).

31. The method of claim 27, further comprising measuring acceleration voltage stability in part based on capacitive discharge associated with a plurality of capacitors in the tandem accelerator system.

32. The method of claim 27, further comprising biasing one or more electrodes of the tandem accelerator system using a DC power supply.

33. The method according to claim 32, wherein, The DC power supply responds to the feedback loop based on capacitive discharge associated with multiple capacitors within the tandem accelerator system.

34. The method of claim 33, further comprising biasing the lead electrode for a duration less than the response time of the feedback loop.

35. The method according to claim 27, wherein, The ion source includes an accelerating electrode.

36. The method of claim 35, further comprising continuously biasing the accelerating electrode using a first power supply.

37. The method of claim 27, wherein, The ion source includes a plasma electrode.

38. The method of claim 37, further comprising continuously biasing the plasma electrode using a second power source.

39. The method according to claim 27, wherein, The negative ion beam passes through a pre-accelerator system downstream of the ion source before reaching the tandem accelerator system.

40. The method according to claim 39, wherein, The duration is short enough to avoid beam-induced damage to components of the pre-accelerator system or the tandem accelerator system.

41. The method according to claim 27, wherein, The duration is sufficient to provide a proton beam with a beam energy of 2.5 MeV.

42. The method according to claim 27, wherein, The duration is sufficient to allow capacitive discharge of no more than 6% to occur within the tandem accelerator system due to the introduction of a negative ion beam.

43. The method according to claim 27, wherein, The ion source includes a non-cesium ion source.

44. The method of claim 27, wherein, The duration is long enough to allow for the extraction of steady-state ions from the ion source.

45. The method according to claim 44, wherein, The steady-state ion extraction ramp-up time of the ion source is 0.1 ms to 0.3 ms.

46. ​​A beam system, comprising: The source includes an extraction electrode, which is configured to generate a beam of charged particles; A modulator system connected to the lead-out electrode of the source, wherein the modulator system is configured to modulate a charged particle beam; and An accelerator configured to accelerate a modulated beam of charged particles, the accelerator including one or more capacitors, wherein the modulated beam does not cause the one or more capacitors to discharge beyond a threshold amount, the threshold amount being 15% or less of the full charge of the one or more capacitors.

47. The beam system according to claim 46, wherein, The modulator system is configured to modulate the charged particle beam into a plurality of pulses, wherein each pulse has a duration sufficient to achieve steady-state particle extraction.

48. The beam system according to claim 46, wherein, The threshold amount is 6% or less of the full charge of the one or more capacitors.

49. The beam system according to claim 47, wherein, The duration is less than 10 milliseconds (ms), and the duty cycle is between 0.1% and 10%.

50. The beam system according to claim 47, wherein, The duration is in the range of 0.5 to 1.0 milliseconds (ms).

51. The beam system according to claim 46, wherein, The modulator system is configured to modulate the charged particle beam to maintain the acceleration voltage stability of the accelerator.

52. The beam system according to claim 51, wherein, The acceleration voltage stability is based, at least in part, on capacitive discharge associated with multiple capacitors of the accelerator.

53. The beam system according to claim 46, wherein, One or more electrodes of the accelerator are biased using a DC power supply.

54. The beam system according to claim 53, wherein, The DC power supply responds to the feedback loop based on capacitive discharge associated with multiple capacitors within the accelerator.

55. The beam system according to claim 54, wherein, The duration is less than the response time of the feedback loop.

56. The beam system according to claim 55, wherein, The accelerator is a tandem accelerator.

57. The beam system according to claim 46, wherein, The charged particle beam is a negative ion beam, and the accelerator is configured to convert the negative ion beam into a proton beam, and each pulse has a duration sufficient to provide a proton beam with a beam energy between 1.9 and 3.0 MeV.

58. The beam system according to claim 46, wherein, The modulation system is configured to modulate the charged particle beam such that capacitive discharge within the accelerator does not exceed 15% during the acceleration of the modulated charged particle beam.

59. The beam system according to claim 46, wherein, The modulation system is configured to modulate the charged particle beam such that capacitive discharge within the accelerator does not exceed 6% during the acceleration of the modulated charged particle beam.

60. The beam system according to claim 58 or 59, wherein, The accelerator is a tandem accelerator, which includes multiple nested shells and one or more capacitors electrically connected between adjacent shells, and the capacitive discharge is the discharge of the one or more capacitors.

61. The beam system according to claim 46, wherein, The accelerator is a tandem accelerator that includes multiple input electrodes, charge exchange devices, and multiple output electrodes.

62. The beam system according to claim 61, wherein, The charged particle beam is a negative ion beam, and the tandem accelerator is configured to accelerate the negative ion beam using the plurality of input electrodes, the charge exchange device is configured to convert the negative ion beam into a positive beam, and the tandem accelerator is configured to accelerate the positive beam using the plurality of output electrodes.

63. The beam system of claim 62, further comprising a target device downstream of the tandem accelerator, wherein the target device is configured to form a neutral beam from the positive beam.

64. The beam system according to claim 63, wherein, The modulator system is configured to modulate a charged particle beam into multiple pulses, each pulse having a finite duration to avoid thermal damage to the target device.

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