Patent ID: 12230453

DETAILED DESCRIPTION

The following disclosure provides many different embodiments, or examples, for implementing different features of the subject matter. Specific examples of components and arrangements are described below to simplify the present disclosure. These are, of course, merely examples and are not intended to be limiting. In addition, the present disclosure may repeat reference numerals and/or letters in the various examples. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed.

Before various embodiments are described in greater detail, it should be understood that the embodiments are not limiting, as elements in such embodiments may vary. It should likewise be understood that a particular embodiment described and/or illustrated herein has elements which may be readily separated from the particular embodiment and optionally combined with any of several other embodiments or substituted for elements in any of several other embodiments described herein. It should also be understood that the terminology used herein is for the purpose of describing the certain concepts, and the terminology is not intended to be limiting. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood in the art to which the embodiments pertain.

In some embodiments, the device may be a pulsed power machine and it may include a plurality of capacitive energy modules. To generate X-rays, the device includes a Marx bank (also referred to capacitor bank), with an output section that contains an anode-cathode gap in vacuum. It is appreciated that energy being discharged from the capacitor bank into the anode-cathode gap generates X-rays. Applications requiring higher X-ray dose that require higher output voltage, e.g., 2.4 MV, 1 MV, etc., may require more capacitive energy modules while lower X-ray dose that require lower output voltage, e.g., 100 kV, 450 kV, etc., may require fewer capacitive energy modules.

As described above, there is a need to create a stack of capacitive energy modules in X-ray generating devices that is serviceable and repairable when one or more of the modules within the stack fails. In other words, one or more failed modules may be replaced/serviced independent of the other modules. The proposed stack of capacitive energy modules allows the modules that have failed to be repaired/replaced while the remaining modules within the stack are reused. Although some of the embodiments described herein describe the use of modules in an X-ray generating device, in other embodiments, the modules may be used in other devices such as electron beam generating devices.

It is appreciated that certain applications may need higher X-ray dose, e.g., for deeper penetration into objects being imaged, while other applications require more dose on target, e.g., for radiation effects characterization. Applications such as these may need an increase in output capacity of the stack of capacitive energy modules. Accordingly, replacing the capacitive energy modules with higher capacity modules, as needed, enables the stack to be used even for higher output applications, e.g., a stack of 70-74 modules may be used to generate 25%-30% more X-ray dose, while retaining the same form factor as the conventional system. Alternatively, higher capacity modules may be used to shorten the length of the stack of capacitive energy modules, thus reducing the form factor of the entire X-ray generating device, e.g., a stack of 55-60 modules may be used to output the same level of X-ray dose as 80 modules of the conventional system. In some embodiments, higher output may also be achieved by using a two-stage electrode within a given capacitive energy module. For example, within the same capacitive energy module two pairs of electrodes may be used where a first set of capacitive energy components (i.e., first stage) are connected to one another through a top and a bottom connection that discharge first before causing a second set of capacitive energy components (i.e., second stage) that are connected to one another through another top and bottom connection to discharge second. Once the second set of capacitive energy components discharge, the result is output from the capacitive energy module and input to a next capacitive energy module in the stack. As such, the output results in an increased voltage output in comparison to a single staged electrode module.

In order to improve the efficiency (by causing discharge to occur in the correct sequence), in some embodiments, the electrodes in each capacitive energy module are positioned in a ladder configuration as opposed to linear configuration. In the ladder configuration the distance between adjacent electrode pairs is less than the distance between adjacent electrode pairs that are in a linear configuration. As such, it is ensured that adjacent electrode pairs discharge in sequence prior to causing the next capacitive energy module to discharge. As such, the output efficiency of the stack of capacitive energy modules is increased.

Each capacitive energy module may include a tray for housing the capacitive energy components that are connected to one another using a plate or connector (top and bottom) to enable the capacitive energy components to charge in parallel and discharge simultaneously (i.e., in series) to generate high energy output. According to some embodiments, the top and the bottom connectors that electrically connect the capacitive energy components to their respective polarity may be positioned in an offset position with respect to one another, therefore reducing the likelihood of accidental breakdown of dielectric medium, e.g., air, between the plates, by increasing the distance between the edges of the plates in comparison to the no offset configuration. It is appreciated that the increase in the distance between the edges of the top and bottom plates with respect to one another reduces arcing between the top plate and the bottom plate as they are held at opposite high voltage polarities.

It is appreciated that in one aspect of the present embodiments the capacitive energy components of each module are connected to two electrodes rather than four electrodes of the conventional system. It is appreciated that the modules are connected to one another to form a stack of capacitive energy modules using plugs connectors that makes a solid contact as opposed to spring loaded contacts of the conventional device. It is appreciated that in some embodiments, high wattage resistors are used in the electrical charging and discharging path instead of bare, thin wire inductors that are used in the conventional system and are better suited than the inductors to withstand the reflection due to impedance mismatch caused by changing length of the output anode-cathode gap.

Referring now toFIG.1A, an example of a housing110for capacitive energy modules according to one aspect of the present embodiments is shown. In some embodiments, the stack of capacitive energy module housing110may be cylindrical in shape having an output120. According to some embodiments, the housing110is configured to house a set of capacitive energy modules. It is appreciated that the housing110is shown and described as being cylindrical for illustrative purposes and should not be construed as limiting the scope of the embodiments. For example, a rectangular shape housing may also be used. Referring now toFIG.1B, an example of a housing for capacitive energy modules100connected to an output section130according to one aspect of the present embodiments is shown. In this embodiment, the output120is connected to the output section130. When the energy from the stack of modules in housing110is coupled to the output section130, X-rays are generated towards the target (not shown).

Referring now toFIG.2, a plurality of capacitive modules210according to one aspect of the present embodiments is shown. A stack of capacitive modules200may include a plurality of capacitive modules210, as shown. The number of capacitive modules210may differ from one application to the next. For example, 70-74 capacitive modules210may be stacked together in a 2.4 MV pulsed power machine, in some embodiments.

Referring now toFIG.3, an example of a housing110with a stack of capacitive energy modules200according to one aspect of the present embodiments is shown. The stack of capacitive modules200are housed within the module housing110. As illustrated the stack200is shown outside the housing110for clarity.

Referring now toFIG.4A, an example of a tray410A configured to house one or more energy capacitive components according to one aspect of the present embodiments is shown. The tray410may be manufactured from any suitable plastic material, a non-limiting example including Delrin® (an acetal homopolymer) or Acrylonitrile Butadiene Styrene (ABS), for ease of machining and excellent electrical insulating characteristics. Various components of the module may be assembled within the tray410A. The tray410A may include a plurality of recesses/pockets machined for housing each capacitive energy component, e.g., capacitor. The tray410A may also include certain indentations for placement of electrodes where the capacitors are connected thereto. The tray410A may further include indentation/housing to place the plug or connector for connecting one module of the stack to the next.

Referring now toFIG.4B, a tray410B configured to house one or more energy capacitive components according to one aspect of the present embodiments is shown. It is appreciated that the tray410B is similar to that ofFIG.4Aexcept that the tray410B is used for two-stage capacitive energy module (described later below).

Referring now toFIG.5A, an example of a capacitive energy module according to one aspect of the present embodiments is shown. In this nonlimiting example, the tray410A may be used to assemble various components within. For example, in this embodiment, 12 capacitive energy components540A, e.g., capacitors, may be housed within the tray410A. It is appreciated that the capacitive energy components540A are connected to one another by two plates530A (i.e., a top plate for making electrical connection for one polarity and a bottom plate for making electrical connection for the opposite polarity) connected on either side of the capacitive energy components540A. In this nonlimiting example, the plates530A (top and bottom) are positioned to aligned with respect to one another. The plates530A provide the charging and discharging path for the energy in capacitive energy components540A. The plates530A may be brass plates. It is appreciated that the use of the plate530A is for illustration purposes only and should not be construed as limiting the scope of the embodiments. For example, finger connectors, e.g., brass finger connectors, may be used to make the electrical connection for charging and discharging.

It is appreciated that the capacitive energy components540A may be coupled to electrodes520A (only two in this nonlimiting example as opposed to four electrodes in the conventional device). It is appreciated that the energy output from the capacitive energy components540A is output through the electrodes520A. It is further appreciated that in some embodiments, high wattage resistors545A are used instead of thin, bare wire inductors of the conventional device. The high wattage resistors are used for charging and discharging and better suited to withstand the reflections due to impedance mismatch than thin bare-wire inductors in the conventional system.

It is appreciated that each capacitive energy module may be connected to another module using plugs/connectors550A. The plugs/connectors550A makes solid contact between the modules as opposed to spring loaded contact in the conventional system that may jam and cause electrical arcing leading to corrosion and pitting over time. The table below shows some nonlimiting examples of the parameters associated with the proposed module of some embodiments in comparison to the conventional module.

Referring now toFIG.5B, an example of a two-stage capacitive energy module according to one of the present embodiments is shown. In this nonlimiting example, the tray410B may be used to assemble various components within. This nonlimiting example shows that two sets of 6 capacitive energy components540B each can be housed within a tray410B. Each set of 6 capacitive energy components are connected to each other with plates530B (i.e., a top plate for making electrical connection for one polarity and a bottom plate for making electrical connection for the opposite polarity) connected on either side of the capacitive energy components540B, in this nonlimiting example, the plates may be brass plates. It is appreciated that the top plate and bottom plate may be offset from each other, in this nonlimiting example. It is appreciated that the use of the plate530B is for illustration purposes only and should not be construed as limiting the scope of the embodiments. In other embodiments, the plates may be replaced by strips, for example. In some embodiments, finger connectors, e.g., brass finger connectors, may be used to make the electrical connection for charging and discharging. The top plate and bottom plate are connected to opposite polarities. Each set of 6 capacitive energy components540B may be coupled to two electrodes520B. It is further appreciated that the energy output from one set of 6 capacitive energy components540B is output through one pair of electrodes520B and the energy output from the second set of 6 capacitive energy components540B is output from the second pair of electrodes520B, thus doubling the energy output in this nonlimiting example of a two-stage capacitive energy module. It is further appreciated that in some embodiments, high wattage resistors545B are used instead of thin, bare wire inductors of the conventional device. The high wattage resistors are used for charging and discharging and better suited to withstand the reflections due to impedance mismatch than thin bare-wire inductors in the conventional system.

It is appreciated that each capacitive energy module may be connected to another module using plugs/connectors550B. The plugs/connectors550B makes solid contact between the modules as opposed to spring loaded contact in the conventional system that may jam and cause electrical arcing leading to corrosion and pitting over time. The table below shows some nonlimiting examples of the parameters associated with the proposed module of some embodiments in comparison to the conventional module.

ConventionalProposedParameterModuleModuleNumber of Marx stages per module21 or 2Number of capacitors per module8 (4 per12 (in 1 stage orstage)2 × 6 in 2 stage)Rated voltage of each capacitor30[kV]50[kV]Rated capacitance of each capacitor2300[pF]2100[pF]Energy stored per module8.3 [J] at31.5 [J] at30 [kV]50 [kV]Form factor1.25 inch1.4 inchthickthickNumber of modules in one 2.3 MV8065-70(estimated)

It is also appreciated that 6 (six) proposed capacitive energy modules were tested for X-ray dose by connecting their output to an anode-cathode gap in vacuum for illustrative purposes that should not be construed as limiting the scope of the embodiments. The anode was a 2.4 mm diameter tungsten needle and the cathode was a 9 mm diameter annulus. Each stage of the module was charged to 40 kV and the dose output was monitored with an ion chamber at 1 meter distance away from the cathode plane. Below is a table illustrating the test measurements for illustrative purposes only. The values given under the “Dose (millirad)” column, as shown below, correspond to X-ray output dose measurements as the distance between the node and cathode, i.e., the “A-K gap” increases as the needle erodes. The initial and final values of the A-K gap, in millimeters, is shown in the column labeled “A-K gap”. Each needle eventually wore out and had to be replaced. As such, multiple set of columns are shown for dose measurement with replacement needles. All needles used were identical in shape and size for illustration purposes only.

Dose Measurements Using SixProposed Modules in an X-Ray DeviceNeedle 1Needle 2Needle 3DoseA-KDoseA-KDoseA-KFile #(mrad)gapFile #(mrad)gapFile #(mrad)gap734.50 mm807.462 33916.213 mm746.44|817.24|927.4|759.46|825.65|935.77|767.95|837.54|949.76|777.28|847.61|959.46|787.1↓855.87|96***|797.533 mm868.44|97***|879.06|988.44|887.19|998.9|896.07↓10010.4|907.517 mm101***|102***|1039.21|1049.75|1056.84↓1068.568 mm

It is appreciated that the results of testing of 6 (six) conventional capacitive energy modules in the same X-ray device are also shown below for comparison. It is appreciated that the anode and cathode were similar to the previous tests with the proposed module.

Dose Measurements Using SixConventional Modules in an X-Ray DeviceNeedle 1Needle 2DoseA-KDoseA-KFile #(mrad)gapFile #(mrad)gap07.150 mm163.30 mm16.27|176|26.26|186.1|36.22|196.02|46.12|205.8|pf56.23|215.71|66.01|225.73|75.9|236.06|85.17|245.35|95.78|255.64|10***|265.62|115.3|275.38|125.28|285.27|135.22|295.22|145.27↓305.43|155.173 mm315.25|325.2|335.14|344.88|354.95|364.83|374.73↓384.033 mmpf

It is appreciated that since the assembly in embodiments is not epoxied, each component within the capacitive energy module may be serviced, repaired and replaced without having to replace the entire module. It is appreciated that using plates530A or530B for example for making the electrical connections for polarities of the capacitive energy components540A or540B results in a robust electrical connection, lower time lag (instantaneous discharge), and lower inductance in comparison to other types of connections, e.g., strip connection (discussed in FIGS.7A and7B). It is appreciated that in some embodiments, the plates530A and/or540B may be electrical connected to the capacitive energy components540A and/or540B using screws or a similar attachment mechanism. As such, various components in the capacitive energy module may be disassembled, serviced/repaired, or replaced without having to replace the entire module because various components are assembled in a detachable manner (can be taken apart for example by unscrewing). It is further appreciated that each capacitive energy module (as shown inFIGS.5A/5B) serves as a cover for its adjacent capacitive energy module. In other words, removing one capacitive energy module exposes the adjacent capacitive energy module that was previously covered with the capacitive energy module that is removed, enabling each capacitive energy module to be serviceable/repairable/replaceable.

Referring now toFIGS.6A and6B, a top view of a capacitive energy module according to one aspect of the embodiments is shown. InFIG.6A, similar toFIG.5A, 12 capacitive energy components540are used whereas inFIG.6B, similar toFIG.5B, 6 capacitive energy components540are used. One polarity of the capacitive energy components540is electrically connected using a top plate532(similar to plate530A/530B) and the opposite polarity of the capacitive energy components540is electrically connected using a bottom plate534(similar to plate530A/530B). It is appreciated that in this embodiment, the top plate532and the bottom plate534are offset with respect to one another. Offsetting the top plate532from the bottom plate534increases the distance between the edges of the top and bottom plates532and534respectively, as shown inFIG.6C. It is appreciated that increasing the distance, as illustrated by offsetting the plates532and534with respect to one another, reduces arcing between the top plate532and the bottom plate534as they are held at opposite high voltage polarities. Moreover, increasing the distance between the two plates prevents accidental breakdown of the dielectric medium, e.g., air, that is in between the plates. In other words, the top and the bottom plates may be identical in shape but positioned in a staggered configuration with respect to one another within the same capacitive energy module. It is appreciated that increasing the distance is directly proportional to the high voltage stand-off between the plates, thereby reducing the chance of accidental electrical breakdown of the dielectric medium between the two plates, e.g., air in this case.

Referring now toFIG.7A, an alternative embodiments of capacitive energy module according to one aspect of the present embodiments is shown.FIG.7Ais substantially similar to that ofFIG.5Bwhere two stage electrodes are used. The two-staged electrode and operation thereof is described in great detail inFIG.9. In this embodiment instead of using two plates530(as shown inFIG.5B) to connect the capacitive energy components540, four connectors560A and560B (top connectors) are used (two on top as shown and two on the bottom not shown). The connectors560may be referred to as strip connectors because they are configured as a strip rather than a plate. The connector560A and its bottom connector (not shown) connects the first stage of the capacitive energy components540to the first set of two electrodes520while the connector560B connects the second stage of the capacitive energy components540to the second set of two electrodes520. In this example, the top connector560A and its bottom connector (not shown) cause the four capacitive energy components540that they are connected to discharge first through the first pair of electrodes causing the connector560B and its corresponding bottom connector (not shown) to cause the capacitive energy components540that they connect to discharge to the next capacitive energy module (described in greater detail inFIG.9). It is appreciated thatFIG.7Ashows the top capacitive energy module that is adjacent the rest of the modules that form the stack as shown inFIG.7B. It is further appreciated thatFIG.7Amay include the proposed capacitive energy module in this one aspect of the embodiment having four electrodes (two sets of two) in a ‘ladder configuration’ or ‘linear configuration’ of the four electrodes (two sets of two). The ladder configuration is described in great detail inFIGS.8A-8B.

It is appreciated that the capacitive energy modules, as described above, regardless of whether a single staged electrodes are used or two-staged electrodes, whether a plate is used or a strip connector is used to connect the capacitive energy components, etc., may use banana plugs and jacks for electrical connections to connect the capacitive energy modules to one another. Moreover, the capacitive energy modules may use high wattage resistors, as described above.

Referring now toFIGS.8A and8B, a ladder configuration of a two-staged electrode according to some embodiments is shown. It is appreciated that this ‘ladder configuration’ may be more efficient in the discharge process of the energy from the stack of capacitive energy modules.FIG.8Aillustrates the ‘ladder configuration’ of the electrodes whileFIG.8Billustrates the discharge path forFIG.8Afor illustrative purposes. It is appreciated that only 3 modules are shown inFIGS.8A-8Bfor illustrative purposes and that any number of modules may be present. In order to improve the efficiency (by causing discharge to occur in the correct sequence), in some embodiments, the electrodes in each capacitive energy module are positioned in a ladder configuration as opposed to linear configuration. In ladder configuration the pairs of electrodes are not within the same plane (i.e., not coplanar) but rather are on different planes creating the ladder configuration. In the ladder configuration the distance between adjacent electrode pairs is less than the distance between adjacent electrode pairs in linear configuration. As such, it is ensured that adjacent electrode pairs discharge in sequence prior to causing the next capacitive energy module to discharge. For example, the top pair of electrodes in module3discharges first followed by the second pair of electrodes after which the discharge causes the first pair of electrodes in module2to discharge followed by the second pair of electrodes in module2and a similar process continues with module1and beyond. As such, the output efficiency of the stack of capacitive energy modules is increased. One of the advantages of the ladder configuration for the electrodes is to ensure that adjacent stages in a stack of capacitive energy modules discharge their energies in a consecutive manner, i.e., without skipping intermediate stages. The linear configuration may be allowing non-consecutive stages to discharge out of sequence, thereby reducing output efficiency. Moreover, the distance between the adjacent electrode pairs in ladder configuration is less than the distance between adjacent electrode pairs in the linear configuration that further ensures consecutive discharge within each module.

FIG.9shows the operation of a two-staged electrode within a single capacitive energy module according to one aspect of the embodiments is shown. In this nonlimiting example, a top plate910A (similar to plate530B) electrically connects the capacitive energy components940A (similar to capacitive energy components540B) to one polarity while a bottom plate912A (similar to plate530B) electrically connects the capacitive energy components940A to its opposite polarity. It is appreciated that a first stage electrode module920A (comprising a pair of electrodes) may be connected to the top plate910A. It is appreciated that the top plate910A, the bottom plate912A, the capacitive energy components940A, and the first stage electrode module920A may form a first stage of the two-staged electrode within a single capacitive energy module. Similarly, a top plate910B (similar to plate530B) electrically connects the capacitive energy components940B (similar to capacitive energy components540B) to one polarity while a bottom plate912B (similar to plate530B) electrically connects the capacitive energy components940B to its opposite polarity. It is appreciated that a second stage electrode module920B (comprising a pair of electrodes) may be connected to the top plate910B. It is appreciated that the top plate910B, the bottom plate912B, the capacitive energy components940B, and the second stage electrode module920B may form a second stage of the two-staged electrode within a single capacitive energy module. It is appreciated that in this embodiment, the plates are shown in an offset configuration (as described above) for illustrative purposes and should not be construed as limiting the scope of the embodiments. For example, a non-offset configuration may be used instead. Moreover, it is appreciated that the connection for the polarities of the capacitive energy components are described with respect to a plate for illustrative purposes only and should not be construed as limiting the scope of the embodiments. For example, a strip connector may be used instead.

In this example, the first stage electrode module920causes a discharge of the capacitive energy components940A. The discharge goes through the bottom plate912A and to the second stage electrode module920connected to the top plate910B of the capacitive energy components940B. The discharge from the first stage causes a discharge by the capacitive energy components940B that goes through the bottom plate912B and out to the next capacitive module in the stack. As a result, the voltage output is increased in comparison to a single staged electrode module.

Referring now toFIGS.10A-10B, examples of banana connectors and receptacles are shown in some non-limiting configurations of the present embodiments in comparison to conventional modules for illustrative purposes. It is appreciated that the configuration of the plug and receptacle in adjacent modules have a single geometry, as shown inFIG.10B, as opposed to a ‘left’ and ‘right’ orientation of the conventional module, as shown inFIG.10A. It is appreciated that this single geometry allows for any damaged module in the stack to be replaced with a new module. Moreover, it is appreciated that only 4 modules are shown inFIGS.10A-10Bfor illustrative purposes and that any number of modules may be present.

Referring now toFIGS.11A-11F, examples of connectors for connecting capacitive energy modules to one another according to some non-limiting embodiments are shown. FIG.11A shows a banana connector1152whileFIG.11Bshows another banana connector1154.FIG.11Cshows a hollow pin banana connector1156whileFIG.11Dshows a banana jack1159connector.FIG.11Eshows the bullet connector1157whileFIG.11Fshows spade connector1158. It is appreciated that the connectors as shown inFIGS.11A-11F, may be used to connect one capacitive energy module of the stack to another capacitive energy module of the stack. Moreover, it is appreciated that use of the connectors as shown is for illustrations purposes and should not be construed as limiting the scope of the embodiments. For example, any connector that makes a solid contact may be used instead of a spring loaded contact.

Referring now toFIGS.12A-12B, examples of stacked modules according to some embodiments are shown. Referring toFIG.12A, a stack of capacitive modules210A-C is shown. Referring toFIG.12B, another stack of capacitive modules is shown.FIG.12Bshows more capacitive energy modules in one stack in comparison toFIG.12A. As such, if each capacitive energy module is configured to generate the same amount of energy, then inFIG.12Bmore energy can be generated and as such can be used for higher X-ray dose allowing for applications that require deeper penetration into objects for imaging. It is further appreciated that the form factor of the X-ray generating device may become smaller by using higher energy generating modules.

It is appreciated that the conventional stack of modules that are epoxied use two orientations between the modules connecting pins and receptacles. As such, in order to make a complete Marx, left and right modules must be stacked alternatingly in order to pass the electrical connections. Thus, when one module fails, e.g., left module, it cannot be replaced with a right module and vice versa. In contrast, the proposed stack of modules use a single design and orientation, thus making each module serviceable and replaceable (i.e., any module can be replaced without regards of its orientation since they all have the same design and orientation).

The foregoing description of various embodiments of the claimed subject matter has been provided for the purposes of illustration and description. It is not intended to be exhaustive or to limit the claimed subject matter to the precise forms disclosed. Many modifications and variations will be apparent to the practitioner skilled in the art. Embodiments were chosen and described in order to best describe the principles of the invention and its practical application, thereby enabling others skilled in the relevant art to understand the claimed subject matter, the various embodiments and the various modifications that are suited to the particular use contemplated.