Overvoltage protection of accelerator components

Abstract

An overvoltage protection system for an accelerator can include a plurality of DC power supplies and an acceleration tube. The plurality of DC power supplies are configured to provide a plurality of voltage levels up to a desired voltage level. The acceleration tube is electrically connected to the plurality of DC power supplies and is configured to accelerate charged particles. The acceleration tube can include a plurality of stages. Each stage can include a plurality of electrodes and a plurality of varistors configured to release energy in response to an overvoltage event. One of the plurality of electrodes can be electrically coupled to one of the plurality of voltage levels. The plurality of electrodes and the plurality of varistors can be electrically coupled to each other and arranged in an alternating fashion.

Description

[0001] Cross-reference to related applications

[0002] This application claims priority to U.S. Provisional Application No. 63 / 024,102, filed May 13, 2020, the entire contents of which are incorporated herein by reference. Background Technology

[0003] Accelerators are used in a wide variety of fields that require high-energy particle beams or ions. Such fields include medical applications such as radiotherapy or neutron capture therapy, ion implantation, industrial processing, biomedical applications, and nuclear physics research. But regardless of whether the application is research-based or industry-based, accelerators typically involve high-voltage, electrically sensitive components, making them susceptible to electrical breakdown.

[0004] Insulating materials are commonly used to surround, isolate, and protect sensitive electrical components. However, these materials can experience electrical breakdown and / or flashover due to overvoltage. Electrical breakdown occurs when current flows through an insulator at a voltage exceeding the material's breakdown voltage. This can damage the material and / or make it more conductive, thus removing the insulating layer from sensitive electrical components. Without the insulating layer, sensitive electrical components may experience severe damage and failure. Flashover can occur along the surface of the insulator. Flashover can cause localized carbonization of the (conductive) surface and may lead to runaway states, resulting in short circuits. Overvoltage can cause voltages in circuits or portions of circuits in an accelerator system to exceed design limits or breakdown voltages, creating potentially hazardous and destructive conditions. Overvoltage can take the form of voltage spikes or power surges. Summary of the Invention

[0005] According to one aspect of this disclosure, an overvoltage protection system for an accelerator may include: a plurality of DC power supplies and an accelerating tube; the plurality of DC power supplies are configured to provide a plurality of voltage levels up to a desired voltage level; the accelerating tube is electrically connected to the plurality of DC power supplies and is configured to accelerate charged particles. The accelerating tube may include multiple stages. Each stage may include a plurality of electrodes and a plurality of rheostats, the plurality of electrodes and the plurality of rheostats being configured to release energy in response to an overvoltage event. One of the plurality of electrodes may be electrically coupled to one of the plurality of voltage levels. The plurality of electrodes and the plurality of rheostats may be electrically coupled to each other and arranged in an alternating manner.

[0006] In some embodiments, each stage may include multiple insulators, each insulator arranged in parallel with a rheostat. In some embodiments, each stage may include multiple water resistors, each water resistor arranged in parallel with a rheostat and an insulator. In some embodiments, each rheostat may be connected between the output of the power supply and a relative ground of the power supply. In some embodiments, each rheostat may be a metal oxide rheostat. In some embodiments, each rheostat may include a rheostat assembly. A rheostat assembly may include a linear stack of rheostat elements. In some embodiments, each rheostat element may be disk-shaped.

[0007] In some embodiments, each of the plurality of DC power supplies may be connected in parallel with a variable resistor. In some embodiments, each of the plurality of DC power supplies may include a Cockcroft-Walton multiplier. In some embodiments, each of the plurality of DC power supplies may be connected in series. In some embodiments, each variable resistor may include a threshold voltage. Each variable resistor may be configured to limit current to the power supply in response to a voltage across the variable resistor exceeding the threshold voltage. In some embodiments, limiting current to the power supply may include releasing energy stored in at least one capacitor within the plurality of power supplies.

[0008] According to another aspect of this disclosure, a protection system for an accelerator may include: multiple DC power supplies, multiple rheostats, and an accelerating tube. The multiple DC power supplies are configured to provide multiple voltage levels up to a desired voltage level; the accelerating tube is electrically connected to the multiple power supplies and configured to accelerate charged particles. Each of the multiple rheostats may be connected in parallel with a DC power supply. The accelerating tube may include multiple stages. Each stage may include multiple electrodes, multiple insulators, and multiple water resistors, the multiple water resistors being configured to release energy and grade voltages across the multiple insulators in response to an overvoltage event. One of the multiple electrodes may be electrically coupled to one of the multiple voltage levels. The multiple insulators and multiple water resistors may be connected in electrical parallel.

[0009] In some embodiments, each rheostat may include a rheostat assembly. A rheostat assembly may include a linear stack of rheostat elements. In some embodiments, each DC power supply may include a Cockcroft-Walton multiplier. In some embodiments, each rheostat may include a threshold voltage. Each rheostat may be configured to release energy stored in at least one capacitor within the plurality of power supplies in response to a voltage across the rheostat exceeding the threshold voltage.

[0010] According to another aspect of this disclosure, a method for protecting components of an accelerator may include: providing multiple voltage levels up to a desired voltage level via multiple DC power supplies; accelerating one or more charged particles via an accelerating tube electrically connected to the multiple DC power supplies; and releasing energy stored in at least one capacitor within the multiple DC power supplies via multiple rheostats. The accelerating tube may include multiple stages. Each stage may include multiple electrodes and multiple rheostats configured to release energy in response to an overvoltage event. One of the multiple electrodes may be electrically coupled to one of the multiple voltage levels. The multiple electrodes and multiple rheostats may be electrically coupled to each other and arranged in an alternating manner.

[0011] In some embodiments, energy stored in at least one capacitor within a plurality of DC power supplies may be released in response to an overvoltage event. In some embodiments, each stage may include a plurality of insulators. Each insulator may be arranged in parallel with a rheostat. In some embodiments, each rheostat may include a rheostat assembly. A rheostat assembly may include a linear stack of rheostat elements. Attached Figure Description

[0012] The various objects, features and advantages of the disclosed subject matter can be more fully understood when considered in conjunction with the following figures and with reference to the following detailed description of the disclosed subject matter, wherein like reference numerals denote like elements.

[0013] Figure 1 This is a system for protecting a high-voltage power supply in an accelerator, according to some embodiments of the present disclosure.

[0014] Figure 2 This is a perspective view of an accelerator tube with an overvoltage protection system according to some embodiments of the present disclosure.

[0015] Figure 3 This is a side view of an accelerator with an overvoltage protection system according to some embodiments of the present disclosure.

[0016] Figure 4A This is a perspective view of an MOV component according to some embodiments of the present disclosure.

[0017] Figure 4B This is an exploded view of an MOV component according to some embodiments of the present disclosure.

[0018] Figure 5 This is a front perspective view of an accelerator tube with an overvoltage protection system according to some embodiments of the present disclosure.

[0019] Figure 6 This is another system for protecting high-voltage power supplies in accelerators according to some embodiments of this disclosure.

[0020] Figure 7 This is another system for protecting high-voltage power supplies in accelerators according to some embodiments of this disclosure.

[0021] Figure 8 This is another system for protecting high-voltage power supplies in accelerators according to some embodiments of this disclosure.

[0022] Figure 9 This is another system for protecting high-voltage power supplies in accelerators according to some embodiments of this disclosure.

[0023] Figure 10 This is another system for protecting high-voltage power supplies in accelerators according to some embodiments of this disclosure.

[0024] Figure 11 This is another system for protecting high-voltage power supplies in accelerators according to some embodiments of this disclosure.

[0025] Figure 12 This is another system for protecting high-voltage power supplies in accelerators according to some embodiments of this disclosure.

[0026] The accompanying drawings are not necessarily drawn to scale, nor do they necessarily include all the components of the system. Instead, the focus is usually on explaining the concepts, structures and techniques that this document seeks to protect. Detailed Implementation

[0027] The following detailed description is merely exemplary in nature and is not intended to limit the invention or its applications.

[0028] Embodiments of this disclosure relate to a system for protecting insulators and high-voltage power supplies in a particle accelerator from electrical breakdown and / or flashover that may occur during an overvoltage event. The accelerator may be an electrostatic accelerator and may be single-ended or connected in series. In some embodiments, the accelerator may include multiple high-voltage power supplies connected in series, each of which can power a subsequent power supply. In some embodiments, the accelerator assembly may include a linear chain of rheostats (e.g., metal oxide rheostats or MOVs) between each insulating member of the accelerator tube. The linear chain of rheostats can provide substantial protection against overvoltage events for each insulating member and power supply.

[0029] Accelerator systems have insulators designed to prevent overvoltage breakdown and / or flashover events. Typically, spark gaps are used to protect insulators in various other applications. A spark gap can be a gap between two conductive electrodes filled with a gas (e.g., air, sulfur hexafluoride); this gap allows an electric spark to pass between the conductors. When the voltage between the conductors exceeds the breakdown voltage (e.g., due to a voltage surge or overvoltage event), a spark is formed, ionizing the gas in the gap, dissipating energy, and reducing resistance, thus protecting sensitive components. While spark gaps are widely used and inexpensive, they can have significant drawbacks, especially in accelerators. SF6 (sulfur hexafluoride) spark gaps can have a wide range of design variables that influence their design, such as gas purity, gas pressure, gap distance, geometry, etc. The large number of variables that need to be considered and controlled when designing an accelerator system with spark gap protection can make it difficult to control the timing and voltage setpoint of each spark gap. Furthermore, spark gaps can be susceptible to time lag. As the rise time of an event increases and the voltage at spark gap ignition increases, the time before spark gap ignition can also increase, which may fail to protect the insulator.

[0030] Furthermore, certain types of accelerators may have additional components (besides insulators) that are sensitive to and susceptible to overvoltage events. For example, electrostatic accelerators utilize high-voltage power supply components that can be severely damaged by overvoltage events. Unlike the alternating current and dynamic potentials used in linear accelerators (linear particle accelerators), magnetic induction accelerators, and cyclotron accelerators, electrostatic accelerators use DC voltages to accelerate particles. However, generating sufficiently high DC voltages within the accelerator to accelerate particles to the necessary energy levels typically involves complex circuitry and sensitive components such as diodes and capacitors to amplify the voltage. One example of this is the Cockcroft-Walton circuit, or multiplier. In some embodiments, a Cockcroft-Walton multiplier may include chains or ladders of high-voltage diodes to amplify the voltage level. Components in the high-voltage power supply may also be susceptible to overvoltage events and electrical breakdown. Many attempts to protect sensitive components (such as insulating materials) in accelerator assemblies fail to protect the high-voltage power supply; these attempts often involve only a single, large high-voltage power supply. Therefore, in addition to being unable to protect a single high-voltage power supply, these attempts are even less effective at protecting multiple high-voltage power supplies in the same system.

[0031] Metal oxide varistors (MOVs) can be used as overvoltage protection devices in electrostatic accelerators. MOVs have resistance that varies with voltage, preventing other components from receiving excessive current. MOVs can have a positive region with high resistance and conduct very small currents at low voltages. However, when the voltage increases beyond the varistor voltage, the resistance of the MOV can decrease significantly, greatly increasing the current flowing through it. The inherent response time of MOV materials can be on the order of 500 picoseconds, and MOV devices can operate in the range of 1–10 nanoseconds. The use of MOVs can also provide accurate voltage thresholds where overvoltages will activate accelerator components and protect insulators from environmental changes. The resistive characteristics of MOVs and the rate at which they can release stored energy within the system during overvoltage conditions can help suppress the discharge of stored energy, protecting insulators and high-voltage power supplies within accelerator components. When an MOV is turned on, connecting it in series between the power supply output and the power supply's relative ground can cause a short circuit. This short circuit can then release energy stored in capacitors within the power supply. Although not all the stored energy in the system is in the power supply capacitor, the capacitance of the entire structure system can be discharged through the MOV chain.

[0032] Figure 1 This is a system 100 for protecting a high-voltage power supply in an accelerator, according to some embodiments of the present disclosure. System 100 may also protect insulators. System 100 may include an accelerator support structure 101 (sometimes referred to as a column) and an accelerator tube 103. Accelerator support structure 101 may include power supplies 102a-102b (generally referred to herein as power supply 102), a first plurality of structural insulators 110a-110n (generally structural insulator 110), and a second plurality of structural insulators 112a-112n (generally structural insulator 112).

[0033] Accelerator support structure 101 can provide structural support and various voltage levels to accelerator tube 103. During operation, accelerator tube 103 can be used to accelerate charged particles or charged particle beams to desired energy levels. Accelerator tube 103 may also be referred to as a vacuum tube. Each power supply unit 102 can include the required electrical charge to the component. For example, each power supply 102 can provide 10 kW, or 200 kV and 50 mA to the component. Each power supply 102 can include various sensing circuits to control the power supply. The sensing circuits may also be susceptible to damage from overvoltage events and can therefore be protected by the MOV device of this disclosure. Note that system 100 is not limited to two power supplies 102a and 102b, and therefore not limited to two voltage levels. In some embodiments, accelerator support structure 101 can include fifteen or more power supplies or stages to create fifteen or more voltage levels. In some embodiments, each power supply can be uniformly spaced along accelerator structure 101. In some embodiments, power supply 102 can include a Cockcroft-Walton multiplier. A certain voltage level can be provided from a standard voltage source, and each stage of the power supply circuit (e.g., power supply 102a, power supply 102b, etc.) can increase the voltage by a predetermined amount. For example, assuming an input voltage of 100kV, each power supply can subsequently increase the voltage by 100kV. As further described below, the continuous increase in voltage level can generate an electric field within the accelerating tube 103, which can then be used to accelerate particles. The voltage level of each power supply 102 can be determined based on the desired final energy level of the particles.

[0034] In some embodiments, the accelerator tube 103 may include a plurality of voltage setting electrodes 104a-104n (typically voltage setting electrodes 104), a plurality of MOVs 106a-106n (typically MOV 106), a plurality of electrical insulators 108a-108n (typically insulator 108), and a plurality of secondary electrodes 114a-114n (typically secondary electrodes 114). In some embodiments, the secondary electrodes 114 may transmit, shape, and control the trajectory of protons (or other charged particles) traveling within the accelerator tube 103. The secondary electrodes 114 may also grade the electric field to help provide linear acceleration. In some embodiments, the placement of the MOV 106 may protect the power supply 102, structural insulators 110 and 112, and insulator 108 from electrical breakdown and / or flashover during overvoltage events. For example, as previously described, when the voltage across a rheostat (e.g., an MOV or any other type of rheostat) increases, the resistance of the material decreases. For rheostats, there exists a threshold voltage at which the rheostat can switch from high resistance to high conductivity (i.e., the rheostat switches from low current operation to extremely high current operation). Therefore, in response to overvoltage events and large surges in high voltage, the resistance of each MOV may decrease, thereby increasing the current flowing through the MOV. This benefit can also come from the parallel arrangement of the MOV and the insulator. Because the total current through the parallel components (e.g., the sum of the currents through the two parallel components) will remain consistent and the rheostat is configured (e.g., in response to overvoltage events) to absorb a large amount of current, this prevents excessive current from flowing through the insulator. Excessive current through the insulator can cause serious damage and failure, especially at particle accelerator operating levels. The response time of the MOV enables it to quickly and effectively prevent current from damaging these components.

[0035] In some embodiments, each voltage setting electrode 104 can be electrically connected to a power supply 102 and operate at the voltage level of the power supply 102. For example, the voltage at point A can be 100 kV; conversely, the voltage at voltage setting electrode 104a will also be 100 kV. Power supply 102a can increase the voltage from 100 kV to 200 kV, thereby setting the voltage at point B and voltage setting electrode 104b to 200 kV. Similarly, power supply 102b can increase the voltage from 200 kV to 300 kV, thereby setting the voltage at point C and voltage setting electrode 104n to 300 kV. Although in Figure 1 The accelerating tube is not explicitly and / or figuratively shown, but the voltage setting electrode 104 creates a uniform or nearly uniform voltage difference along the internal region of the tube, thereby inducing a uniform or nearly uniform electric field in the horizontal direction of the accelerating tube. The resulting electric field can be used to accelerate particles.

[0036] The power supply and associated voltage setting electrodes may be referred to herein as a stage. A stage may further include an MOV and a secondary electrode between the associated voltage setting electrode and the voltage setting electrode of the preceding stage. For example, power supply 102a and voltage setting electrode 104b may form a first stage, and power supply 102b and voltage setting electrode 104n may form a second stage. The first stage may include MOVs 106a-106g, secondary electrodes 114a-114f, and insulators 108a-108g. The second stage may include MOVs 106h-106n, secondary electrodes 114g-114n, and insulators 108h-108n. In some embodiments, secondary electrodes 114 and MOV 106 may be connected alternately. Note that... Figure 1 This is merely illustrative in nature, and the accelerator system is not limited to two stages. In some embodiments, the accelerator may include up to 15 or more stages. Each stage may include alternating MOVs and secondary electrodes. In some embodiments, each stage may also include an insulator connected in parallel with each MOV. In some embodiments, MOV106 may be an MOV component, such as... Figure 4A and Figure 4B Component 400. In other words, MOV106 may include one or more individual MOVs. In embodiments where each MOV106 includes multiple MOVs, the MOVs may be arranged in series or in a linear chain.

[0037] Figure 2 This is a perspective view of an accelerating tube with an overvoltage protection system 200 according to some embodiments of the present disclosure. System 200 may include an accelerating tube 103 and stages 206a-206g (typically stage 206). Note that these are not shown in this figure. Figure 1 The accelerator structure 101. Each stage 206 may include a voltage setting electrode 104 and multiple alternating MOVs and secondary electrodes 204 (e.g., Figure 1 (Secondary electrode 114 and MOV 106). In some embodiments, each stage may further include an insulator connected in parallel with the MOV, such as... Figure 1 Insulator 108. For example, stage 206a may include voltage setting electrode 104a and multiple alternating MOV and secondary electrodes 204a. Each voltage setting electrode 104 may be configured to be electrically coupled to a separate high-voltage power supply (e.g., a separate Cockcroft-Walton multiplier and power supply) and thus set at a specific voltage level, as per [reference to...]. Figure 1 As described, each voltage setting electrode 104 can be configured to set the voltage level within the acceleration tube 103, thereby generating a uniform or nearly uniform electric field within the acceleration tube 103. Particles can then be accelerated within the acceleration tube 103.

[0038] Figure 3This is a side view of an accelerator with an overvoltage protection system 300 according to some embodiments of the present disclosure. System 300 may include an accelerator structure 101, an accelerator tube 103, and a plurality of electrical insulators 302a-302n (e.g., ...). Figure 1 Insulators 110a-110n in some embodiments. In some embodiments, accelerator structure 101 may include insulators 110a-110n in some embodiments. Figure 1 Multiple high-voltage power supplies 102a-102e, similar or identical to those described herein, are used. The accelerating tube 103 can be configured to accelerate particles via a DC electric field. Voltage setting electrodes 104a-104d can be electrically coupled to the power supply 102 at a relevant voltage, thereby setting various voltage levels within the accelerating tube 103. (The remaining text appears to be unrelated and possibly a fragment from another document.) Figure 1 and Figure 2 The stage is defined as described. For example, a power source 102b and a voltage setting electrode 104b can form a stage; the stage may also include MOVs 106a-106c and at least secondary electrodes 114a-114c. The stage may also include an electrical insulator. For example, a stage including power source 102a and voltage setting electrode 104a may also include an electrical insulator 302b. The electrical insulator 302b may physically cover the secondary electrode 114.

[0039] Figure 4A This is a perspective view of an MOV component 400 according to some embodiments of the present disclosure. Figure 4B This is an exploded view of an MOV component according to some embodiments of the present disclosure. In some embodiments, the MOV component 400 can be used as... Figures 1 to 3 MOV 106 in any of these. MOV assembly 400 may include MOV disks 402a-402h, tie rods 404a-404d, end mounts 406a-406b, and center mount 408. In some embodiments, MOV disks 402a-402h may be arranged in a “stacked” configuration. This stacked arrangement can ensure good electrical connection during conduction. Because each rheostat disk in the stack may be “forced” to come closer together, the increased mechanical stress can help increase the electrical connection. In some embodiments, the MOV disks may be arranged in other geometries. In some embodiments, each MOV (e.g., MOV 402) may be a shape other than a disk; for example, each MOV may be a cube, prism, or any other cross-sectional shape. Center mount 408 and end mounts 406a-406b may be configured to receive tie rods 404, thereby structurally securing the MOV assembly to an acceleration tube, such as acceleration tube 103. The middle mounting 408 and the end mountings 406a-406b can also be configured to receive the MOV disk 402 and hold the MOV disk 402 in place.

[0040] MOV disk 402 can comprise any metal oxide material. In some embodiments, the voltage trigger point of the rheostat assembly can be 24 kV per electrode / insulator. An example MOV disk could be the Dean Technologies BHD1375-AL. For instance, this rheostat could provide a total rated voltage V of 24 kV per insulator. rms In some embodiments, a single MOV disk may include electrical characteristics / ratings, such as 6kV and 55kA. In some embodiments, the diameter of the MOV disk may be 32mm and the length may be 42mm. In some embodiments, the MOV assembly 400 may include fewer or more than eight MOV disks, depending on the desired protection level for each component. In some embodiments, the MOV disks 402 may be arranged in series. The total resistance of the series-connected components is the sum of the resistances of each individual component. Therefore, regarding Figure 4A and Figure 4B The total resistance of MOV component 400 can be the sum of the resistances of each of MOV402a-402h.

[0041] In some embodiments, the MOV assembly 400 may span three electrodes. The center of the assembly 400 may have a built-in clamp for attachment to the electrodes. The assembly can be positioned at a small angle such that each end of the MOV assembly 400 can be attached to an adjacent electrode using an aluminum rod and clamps for electrode connection. The MOV assembly 400 can protect two insulators connected in series.

[0042] Figure 5 This is a front perspective view of an accelerating tube with an overvoltage protection system 500 according to some embodiments of the present disclosure. System 500 may include an accelerating tube 103 and multiple stages 206a-206d, the multiple stages 206a-206d being similar to those described in relation to... Figure 2 The described level 206 or as about Figure 2 The described stage 206 is the same. In some embodiments, each stage 206 may include a plurality of alternating MOVs and secondary electrodes 204 (e.g., Figure 1 (Secondary electrodes 114 and MOV 106). Although not visible, each MOV can be arranged in parallel with insulating material to protect the insulating material. In the event of an overvoltage event, one or more MOVs can respond to a voltage surge by reducing their resistance and increasing the amount of current flowing through the MOVs. Essentially, one or more MOVs may start operating as an electrical short circuit and can prevent the protected components (e.g., insulating material or high-voltage power supply) from receiving excessive current and being damaged.

[0043] Figure 6This is another system 600 for protecting a high-voltage power supply in an accelerator, according to some embodiments of the present disclosure. Similar to system 100, system 600 may include an accelerator support structure 101 and an accelerator tube 103. The accelerator support structure 101 may include a power supply 102, a first plurality of structural insulators 110, and a second plurality of structural insulators 112.

[0044] Similar to Figure 1 In system 100, accelerator support structure 101 can provide structural support and different voltage levels to accelerator tube 103. During operation, accelerator tube 103 can be used to accelerate charged particles to a desired energy level. Power supply 102 can include circuitry for boosting and generating various levels of DC voltage up to a desired level. Note that system 600 is not limited to two power supplies 102a and 102b, and therefore not limited to two voltage levels. In some embodiments, accelerator support structure 101 can include fifteen or more power supplies or stages to create fifteen or more voltage levels. In some embodiments, each power supply can be evenly spaced along accelerator structure 101. In some embodiments, power supply 102 can include Cockcroft-Walton multipliers. A certain voltage level can be provided from a standard voltage source, and each stage of the power supply circuitry (e.g., power supply 102a, power supply 102b, etc.) can boost the voltage by a predetermined amount. For example, assuming an input voltage of 100 kV, each power supply can subsequently boost the voltage by 100 kV. As further described below, a continuous increase in voltage level can generate an electric field within the accelerating tube 103, which can then be used to accelerate particles. The voltage level of each power source 102 can be determined based on the desired final energy level of the particles.

[0045] System 600 may include a plurality of power resistors 601a-601n (generally referred to herein as power resistor 601). In some embodiments, each power resistor 601 may be electrically positioned between a voltage setting electrode 104 and an associated power source. For example, power resistor 601b may be positioned between voltage setting electrode 104b and power source 102a (a power source that provides a voltage level to voltage setting electrode 104b). In some embodiments, during an overvoltage event, each power resistor 601 may prevent a voltage surge between accelerator structure 101 and accelerator tube 103. Power resistors are typically designed to withstand and dissipate large amounts of power and may comprise materials with high thermal conductivity.

[0046] Figure 7This is another system 700 for protecting a high-voltage power supply in an accelerator, according to some embodiments of the present disclosure. Similar to system 100, system 700 may include an accelerator support structure 101 and an accelerator tube 103. The accelerator support structure 101 may include a power supply 102, a first plurality of structural insulators 110, and a second plurality of structural insulators 112.

[0047] System 700 may include multiple MOVs 106a-106n and multiple electrical insulators 108a-108n. As described above, the placement of MOVs 106 can protect power supply 102, structural insulators 110 and 112, and insulator 108 from electrical breakdown and / or flashover during overvoltage events. In some embodiments, system 700 may also include multiple water resistors 701a-701n (typically 701 as described herein). In some embodiments, each water resistor 701 may operate as a variable resistor (e.g., a rheostat) and may have a resistance that varies with voltage. In addition to MOVs 106, water resistors 701 can also help protect power supply 102, structural insulators 110 and 112, and insulator 108 from electrical breakdown and / or flashover during overvoltage events. In some embodiments, water resistors 701 can ensure uniform voltage gradation across insulator 108. In some embodiments, each of the MOV (e.g., 106a), the electrical insulator (e.g., 108a), and the water resistor (e.g., 701a) may be connected in parallel between the two electrodes (e.g., 104a and 114a). In some embodiments, this helps to ensure uniform gradation and protection along the length of the accelerating tube 103.

[0048] Figure 8 This is another system 800 for protecting a high-voltage power supply in an accelerator, according to some embodiments of the present disclosure. Similar to system 100, system 800 may include an accelerator support structure 101 and an accelerator tube 103. The accelerator support structure 101 may include a power supply 102, a first plurality of structural insulators 110, and a second plurality of structural insulators 112.

[0049] Similar to the above about Figure 7 As described, system 800 may include multiple MOVs 106a-106n, multiple electrical insulators 108a-108n, and multiple water resistors 701a-701n. Furthermore, system 800 may include multiple power resistors 601a-601n. (As described above regarding...) Figure 6As described, each power resistor 601 can be electrically positioned between the voltage setting electrode 104 and the associated power source. For example, a power resistor 601b can be positioned between the voltage setting electrode 104b and the power source 102a (which provides a voltage level to the voltage setting electrode 104b). In some embodiments, during an overvoltage event, each power resistor 601 can prevent a voltage surge between the accelerator structure 101 and the accelerator tube 103. Power resistors are typically designed to withstand and dissipate large amounts of power and can comprise materials with high thermal conductivity.

[0050] Figure 9 This is another system 900 for protecting a high-voltage power supply in an accelerator, according to some embodiments of this disclosure. System 900 may include multiple electrical insulators 108a-108n and multiple water resistors 701a-701n. Furthermore, system 900 may include multiple MOVs 901 and 902. (See also: Regarding...) Figure 7 and Figure 8 As described, water resistors 701a-701n can be connected in series with insulator 108 between electrodes 114. In some embodiments, the water resistors can provide protection against electrical breakdown and / or flashover during overvoltage events and can grade the voltage across insulator 108. In some embodiments, MOVs 901 and 902 can provide protection for insulators 110 and 112 and power supplies 102a-102b. Note that system 900 is not limited to two MOVs 901 and 902 and can include MOVs for each power supply. For example, if the accelerator has 15 power supplies creating 15 voltage levels within the accelerating tube 103, the system can include 15 MOVs, each connected in parallel with a power supply and an insulator. In some embodiments, power supply-side MOVs 901 and 902 can protect sensitive components included within each power supply 102.

[0051] Figure 10 This is another system 1000 for protecting a high-voltage power supply system in an accelerator, according to some embodiments of this disclosure. Similar to what has been described above. Figure 9 System 1000 may include multiple electrical insulators 108a-108n, multiple water resistors 701a-701n, multiple power-side MOVs 901 and 902, and multiple power resistors 601a-601n, similar to the description of... Figure 6 Those described. In some embodiments, in addition to the protection and voltage grading characteristics that can be provided by the water resistors 701a-701n, the combination of MOVs 901 and 901 and power resistors 601a-601n can provide improved protection for the power supply 102.

[0052] Figure 11This is another system 1100 for protecting a high-voltage power supply system in an accelerator, according to some embodiments of this disclosure. System 1100 may include... Figure 1 , Figure 7 and Figure 9 The combination of various components described. In some embodiments, system 1100 may include multiple MOVs 106a-106n, multiple electrical insulators 108a-108n, multiple water resistors 701a-701n, and multiple power-side MOVs 901 and 902. Similar to the foregoing figures, MOV 106, electrical insulator 108, and water resistor 701 may be connected in parallel between the electrodes and may provide protection against electrical breakdown and / or flashover during overvoltage events. Water resistor 701 may also aid in voltage grading within insulator 108.

[0053] Figure 12 This is another system 1200 for protecting a high-voltage power supply system in an accelerator, according to some embodiments of this disclosure. System 1200 may include... Figure 11 The components described are similar to those described, but may also include multiple power resistors 601a-601n. In some embodiments, the power resistor 601 may be related to... Figure 6 It operates in a similar or identical manner as described. Each power resistor 601 can be electrically positioned between the voltage setting electrode 104 and the associated power source. For example, power resistor 601b can be positioned between voltage setting electrode 104b and power source 102a (a power source that provides a voltage level to voltage setting electrode 104b). In some embodiments, during an overvoltage event, each power resistor 601 can prevent a voltage surge between accelerator structure 101 and accelerator tube 103. Power resistors are typically designed to withstand and dissipate large amounts of power and may comprise materials with high thermal conductivity.

[0054] It should be understood that the disclosed subject matter is not limited in its application to the construction details and arrangement of components described in the following description or shown in the accompanying drawings. The disclosed subject matter can be practiced and implemented in various ways in other embodiments. Furthermore, it should be understood that the wording and terminology used herein are for descriptive purposes and should not be considered limiting. Therefore, those skilled in the art will understand that the concepts on which this disclosure is based can be readily used as the basis for designing other structures, methods, and systems for performing several purposes of the disclosed subject matter. Therefore, it is important that the claims be considered to include such equivalent constructions as long as they do not depart from the spirit and scope of the disclosed subject matter.

[0055] Although the disclosed subject matter has been described and explained in the foregoing illustrative embodiments, it should be understood that this disclosure is by way of example only, and many changes may be made to the details of the implementation of the disclosed subject matter without departing from the spirit and scope of the disclosed subject matter.

Claims

1. An overvoltage protection system for an accelerator, comprising: Multiple DC power supplies, the multiple DC power supplies being configured to provide multiple voltage levels up to a desired voltage level; as well as An accelerating tube, electrically connected to the plurality of DC power supplies and configured to accelerate charged particles, the accelerating tube comprising multiple stages, each stage comprising: Multiple electrodes, wherein one of the multiple electrodes is electrically coupled to one of the multiple voltage levels; and Multiple rheostats, the multiple rheostats being configured to release energy in response to an overvoltage event; The plurality of electrodes and the plurality of rheostats are electrically coupled to each other and arranged in an alternating manner; Each stage includes multiple insulators, and each insulator is arranged in parallel with a rheostat.

2. The overvoltage protection system according to claim 1, wherein, Each stage includes multiple water resistors, each of which is arranged in parallel with a rheostat and an insulator.

3. The overvoltage protection system according to claim 1, wherein, Each rheostat is connected between the output of the DC power supply and the relative ground of the DC power supply.

4. The overvoltage protection system according to claim 1, wherein, Each rheostat is a metal oxide rheostat.

5. The overvoltage protection system according to claim 1, wherein, Each rheostat includes a rheostat assembly, which comprises a linear stack of rheostat elements.

6. The overvoltage protection system according to claim 5, wherein, Each rheostat element is disc-shaped.

7. The overvoltage protection system according to claim 1, wherein, Each of the plurality of DC power supplies is connected in parallel with a variable resistor.

8. The overvoltage protection system according to claim 1, wherein, Each of the plurality of DC power supplies includes a Cockcroft-Walton multiplier.

9. The overvoltage protection system according to claim 1, wherein, Each of the plurality of DC power supplies is connected in series.

10. The overvoltage protection system according to claim 1, wherein, Each rheostat includes a threshold voltage, wherein each rheostat is configured to limit current to a DC power supply in response to a voltage across the rheostat exceeding the threshold voltage.

11. The overvoltage protection system according to claim 10, wherein, Limiting current to the DC power source includes releasing energy stored in at least one capacitor within the plurality of DC power sources.

12. A protection system for an accelerator, comprising: Multiple DC power supplies, the multiple DC power supplies being configured to provide multiple voltage levels up to a desired voltage level; Multiple rheostats, wherein each of the multiple rheostats is connected in parallel with a DC power supply; as well as An accelerating tube, electrically connected to the plurality of DC power supplies and configured to accelerate charged particles, the accelerating tube comprising multiple stages, each stage comprising: Multiple electrodes, wherein one of the multiple electrodes is electrically coupled to one of the multiple voltage levels; Multiple insulators; and Multiple water resistors are configured to release energy and grade the voltage across the multiple insulators in response to an overvoltage event; The plurality of insulators and the plurality of water resistors are connected in parallel.

13. The protection system according to claim 12, wherein, Each rheostat includes a rheostat assembly, which comprises a linear stack of rheostat elements.

14. The protection system according to claim 12, wherein, Each DC power supply includes a Cockcroft-Walton multiplier.

15. The protection system according to claim 12, wherein, Each rheostat includes a threshold voltage, wherein each rheostat is configured to release energy stored in at least one capacitor within the plurality of DC power supplies in response to a voltage across the rheostat exceeding the threshold voltage.

16. A method for protecting components of an accelerator, comprising: Multiple voltage levels, up to the desired voltage level, can be provided via multiple DC power supplies; One or more charged particles are accelerated via accelerating tubes electrically connected to the plurality of DC power supplies, wherein the accelerating tubes comprise multiple stages, each stage comprising: Multiple electrodes, wherein one of the multiple electrodes is electrically coupled to one of the multiple voltage levels; and Multiple rheostats, the multiple rheostats being configured to release energy in response to an overvoltage event; The plurality of electrodes and the plurality of rheostats are electrically coupled to each other and arranged in an alternating manner; Each stage includes multiple insulators, each of which is connected in parallel with a rheostat; and Energy stored in at least one capacitor within the plurality of DC power supplies is released via the plurality of rheostats.

17. The method according to claim 16, wherein, In response to an overvoltage event, energy stored in at least one capacitor within the plurality of DC power supplies is released.

18. The method according to claim 16, wherein, Each rheostat includes a rheostat assembly, which comprises a linear stack of rheostat elements.

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