Ribbon coating by pulsed magnetron sputtering

Abstract

A radial magnetron system for plasma surface modification and high quality film deposition of multi-dimensional structures is described. The system includes an axial electrode, a target material disposed on a portion of the axial electrode, an applied potential from an external power source, and a high current contact attached to the axial electrode for the applied potential. The system also includes a main permanent magnet assembly including individual magnetic material elements configured to generate a target region magnetic field for generating a Hall effect dense plasma region with the applied potential applied to the axial electrode, and a magnet base plate supporting the main permanent magnet assembly within the axial electrode. The magnet base plate is configured to provide a channel for cooling the main permanent magnet assembly and the axial electrode.

Description

[0001] Cross-references to related applications

[0002] This application is a non-provisional application filed on January 20, 2021, entitled “Bellows Coating by Magnetron Sputtering with Kick Pulse”, the entire contents of which are expressly incorporated herein by reference, including any references thereto.

[0003] This application relates to and claims priority to U.S. Application Serial No. 16 / 848,353, which is a partial continuation of U.S. Application Serial No. 15 / 803,320 (USP 10,624,199), filed November 3, 2017, entitled “A COMPACT SYSTEM FOR COUPLING RF POWER DIRECTLY INTO RF LINACS,” which is a non-provisional application of U.S. Provisional Application Serial No. 62 / 416,900, filed November 3, 2016, the contents of each of the above applications are expressly and integrally incorporated herein by reference, including any references herein.

[0004] This application relates to and claims priority to U.S. Application No. 16 / 848,353, which is a partial continuation of U.S. Application Serial No. 16 / 006,357, entitled “PULSEDPOWER MODULE WITH PULSE AND ION FLUX CONTROL FOR MAGNETRON SPUTTERING,” filed June 12, 2018, and which is a non-provisional application of U.S. Provisional Application Serial No. 62 / 518,362, entitled “PULSED POWER MODULE WITH PULSE AND ION FLUX CONTROL FOR MAGNETRON SPUTTERING,” filed June 12, 2017, the contents of each of the above applications being expressly and entirely incorporated herein by reference, including any references herein.

[0005] This application relates to and claims priority to U.S. Application Serial No. 16 / 848,353, which is a partial continuation of U.S. Application Serial No. 16 / 801,002, filed February 25, 2020, entitled “METHOD AND APPARATUS FOR METAL AND CERAMIC NANOLAYERING FOR ACCIDENT TOLERANT NUCLEARFUEL, PARTICLE ACCELERATORS & AEROSPACE LEADING EDGES,” which is a non-provisional application of U.S. Provisional Patent Application Serial No. 62 / 810,230, filed February 25, 2019, entitled “METHOD AND APPARATUS FOR METAL AND CERAMIC NANOLAYERING FOR ACCIDENT TOLERANT NUCLEARFUEL,” the contents of each of the above applications are expressly and entirely incorporated herein by reference, including any references herein. Technical Field

[0006] This disclosure generally relates to injecting power into accelerator devices, and more specifically to relatively compact high-power radio frequency linear accelerator (RF LINAC) systems. More specifically, this additional disclosure, provided in the form of a set of seventeen (17) slides, relates to systems and methods for applying the techniques described herein to provide extremely high-quality coatings on the inner surface of bellows. Background Technology

[0007] High-power RF cavities, such as those found in low-temperature superconducting radio frequency (SRF) LINAC, require not only enormous RF power (approximately 10 to 100 kW and above) but also a vacuum environment to prevent arcing and sparking within the RF cavity due to the strong electric fields associated with such high power. The RF power required to achieve a specific electric field within the resonant cavity is determined by the mass factor (Q), which is the stored integral energy divided by the energy lost per cycle. For resonant RF cavities, this formula simplifies to... This is because RF energy propagates along the surface and is a function of the surface resistance, which is proportional to the square root of the RF frequency. Higher mass factors lead to higher efficiency, higher achievable voltages, and higher acceleration gradients. SRF cavities utilize very high mass factors (on the order of 1E8 to 1E9) to achieve extreme acceleration fields with moderate power input and moderate power consumption. This allows very large-scale particle accelerators, such as the Large Hadron Collider at CERN (European Organization for Nuclear Research) and the Continuous Electron Beam Accelerator Facility at Thomas Jefferson National Accelerator Laboratory, to operate cost-effectively. However, due to the skin depth on the order of micrometers for GHz frequencies, there are engineering trade-offs in cavity design and operation. Cryogenic RF cavities, beamlines, bellows, and waveguide sections are typically made of vacuum-grade stainless steel and plated with copper for lower surface resistivity, or they are made of solid bulk matrix materials such as ultrapure high residual resistivity (RRR) niobium to achieve low-loss superconducting properties. Electroplating and / or machining ultrapure materials into complex vacuum components for accelerator applications is challenging and costly. As accelerators scale up to achieve higher energies (e.g., >10TeV) and devices transition to commercial and industrial applications (e.g., electron beam sources), improvements to existing technologies are needed.

[0008] Wet electroplating is being phased out due to its destructive environmental impact, handling of hazardous chemicals, high costs, and a lack of experienced businesses in the field. The EU has proposed a timeline for the complete phasing out of all electroplating in the coming years, making investment in alternative technologies crucial. After years of decline, only a handful of companies in the US are capable of performing this type of plating. Often, multiple customer parts will be processed using the same tanks, electrodes, and circulating chemical baths, resulting in embedded impurities, non-conformal deposition, and delamination, leading to component scrap, rework, additional costs, and increased timelines. Replacing the error-prone wet electroplating with physical vapor deposition (PVD) is one approach. However, working on the interior and three-dimensional surfaces of parts is difficult and challenging.

[0009] Furthermore, due to the skin depth effect, superconducting fields conduct only on the material surface. When the goal is to deposit or coat only a thin layer of superconducting material on a vacuum surface and design SRF properties, fabricating the entire structure from a solid blank of ultrapure material is a major waste and cost driver. The accelerator community is particularly interested in large-area, conformal SRF coatings because they can be used to construct SRF cavity structures with properties equivalent to or even superior to currently used bulk Nb elliptical cavities, and potentially at a lower cost. In some cases, the focus is on replacing Nb cavities with Nb-coated Cu to reduce costs and improve thermal properties, while in others, the emphasis is on surpassing the RF and / or thermal performance of bulk Nb by using other materials (e.g., Nb3Sn coatings) and / or multilayer structures. A significant challenge here is depositing SRF films onto these cavities: film deposition on curved, complex surfaces is much more difficult than on wafers or test specimens, especially when film parameters (e.g., thickness) need to fall within a set window for the entire cavity structure. This is especially true for multilayer (e.g., SIS) structures, where even small variations in layer thickness can have a profound impact on the final result. Further complicating the process is the presence of particles and defects within the film, whether introduced before, during, or after the coating process. The result of these inclusions is a degradation of the overall film performance, often to an extreme degree.

[0010] This disclosure uses conformal ionization physical vapor deposition (iPVD) instead of wet chemical plating (e.g., Cu) for stainless steel bellows and other specialized vacuum components used in accelerator structures. Summary of the Invention

[0011] This disclosure relates to a radial magnetron system for plasma surface modification and high-quality film deposition of multidimensional structures. The system includes an axial electrode, a target material disposed on a portion of the axial electrode, an applied potential from an external power source, and high-current contacts attached to the axial electrode for the applied potential. The system also includes a main permanent magnet assembly and a magnet substrate. The main permanent magnet assembly includes various magnetic material elements configured to generate a target magnetic field for generating Hall-effect dense plasma regions when the applied potential is applied to the axial electrode, and the magnet substrate supports the main permanent magnet assembly within the axial electrode. The magnet substrate is configured to provide channels for cooling the main permanent magnet assembly and the axial electrode.

[0012] This disclosure also relates to a batch deposition system for depositing high-quality films on multiple surface-treated structures. The system includes a vacuum chamber assembly, a radial magnetron comprising a target material, an external power supply, and a mounting structure for holding the multiple surface-treated structures. The mounting structure is situated between the radial magnetron and the vacuum chamber. During operation, the multiple surface-treated structures are treated using plasma generated in a plasma generation region near the radial magnetron. Furthermore, the external power supply includes field-generating electronics configured to perform: generating a high-power pulsed plasma magnetron discharge using a large-current negative DC pulse applied to an axial electrode; and generating a configurable continuous positive voltage kick pulse supplied to the axial electrode after terminating the negative DC pulse. During generation, logic circuitry configured by a program processor issues control signals to control at least one kick pulse attribute of the continuous positive voltage kick pulse, the kick pulse attribute being derived from the group consisting of a start delay, duration, amplitude, and frequency (including its modulation).

[0013] This disclosure also relates to a roll-to-roll web coating system for simultaneously depositing high-quality films on multiple flexible substrate surfaces from a single radial magnetron. The system includes a vacuum chamber assembly, a radial magnetron comprising a target material, an external power supply, and a roll-to-roll transport system for simultaneously transporting the substrates into a plasma processing zone. During operation, the radial magnetron generates a plasma field for producing the plasma processing zone. The external power supply also includes field generation electronics configured to: generate a high-power pulsed plasma magnetron discharge using a large-current negative DC pulse applied to an axial electrode; and, after terminating the negative DC pulse, generate a configurable continuous positive voltage kick pulse supplied to the axial electrode. During generation, logic circuitry configured by a program processor issues control signals to control at least one kick pulse attribute of the continuous positive voltage kick pulse, the kick pulse attribute being derived from a group consisting of a start delay, duration, amplitude, and frequency including its modulation.

[0014] Additional features and advantages of the invention will become apparent from the following detailed description of illustrative examples with reference to the accompanying drawings. Attached Figure Description

[0015] While the appended claims particularly set forth the features of the invention, the invention, its objects and advantages, may be best understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

[0016] Figure 1A This is an axial schematic diagram applicable to a radial magnetron system incorporating the features of this disclosure;

[0017] Figure 1BThis is a cross-sectional schematic diagram applicable to a radial magnetron system incorporating the features of this disclosure;

[0018] Figure 1C This is a photograph of a radial magnetron system operating under IMPULSE+Positive Kick HiPIMS operation without magnetic rotation.

[0019] Figure 1D This is a photograph of a radial magnetron system operating under IMPULSE+Positive Kick with magnetic rotation, with similar etching process parameters.

[0020] Figure 1E This is a photograph of a radial magnetron system operating under IMPULSE+Positive Kick with magnetic rotation, under similar deposition process parameters.

[0021] Figure 2A A side cross-sectional view along the axis of a high-current radial magnetron system with an internally rotating master sputtering / etching permanent magnet assembly is depicted, which generates a moving target magnetic field coupled to an air-side external magnetic actuator.

[0022] Figure 2B A side cross-sectional view of an illustrative solid model of a radial magnetron is shown, featuring an internal flow channel, a primary magnet placement on the vacuum side for sputtering / etching, a secondary magnet placement on the air side for independent magnetic rotation, a PTFE (polytetrafluoroethylene) bushing for rotation, and an insulator.

[0023] Figure 2C It has IMPULSE +Positive Kick TM Photograph of a high-current radial magnetron system operating in a rotating magnetic field for copper sputtering etching / deposition;

[0024] Figure 3 A cross-sectional view of an illustrative example of a radial magnetron system is depicted, in which a main sputtering / etching permanent magnet assembly partially surrounds the circumference of the radial magnetron, thereby confining a dense plasma region to a discrete region that moves under rotation and / or axial displacement.

[0025] Figure 4A A schematic cross-sectional view along the axis of a high-current radial magnetron system with a vacuum-side master sputtering / etching permanent magnet assembly capable of axial displacement to generate a moving target magnetic field coupled to an air-side external magnetic actuator is depicted.

[0026] Figure 4BThe axial displacement of the main sputtering / etching permanent magnet assembly in a radial magnetron configured for axial movement of the target region magnetic field to generate a dense plasma region for sputtering and etching is further described.

[0027] Figure 4C In Impulse +Positive Kick TM Photograph of a high-current radial magnetron operating under axial displacement, which employs a master sputtering / etching permanent magnet assembly capable of axial displacement;

[0028] Figure 5A This is an illustrative example of the construction of a large radial magnetron axial cylindrical electrode having multiple outward-facing target material portions for sputtering / etching of a long substrate.

[0029] Figure 5B The photograph highlights the use of heat-shrink fitting assembly technology to bond segmented niobium targets to copper axial electrodes;

[0030] Figure 5C This is a photo of an electrode, which is a one-meter-long radial magnetron target, before it is assembled with internal magnetic components and a coolant flow structure.

[0031] Figure 6A The illustration depicts the formation of deep "V" grooves on the surface of sputtered target material without magnet-target rotation;

[0032] Figure 6B The image shows a radial magnetron after operation without magnet-target rotation, revealing a deep "racetrack" pattern of target erosion and inhomogeneity.

[0033] Figure 6C The illustration depicts a more uniform target material erosion pattern on the target surface resulting from magnet-target rotation (relative motion between the dense plasma region and the sputtered target material) and the elimination of the deep “V” groove, leading to better utilization and process uniformity.

[0034] Figure 6D The image shows a radial magnetron after operation with the magnet and target rotating, demonstrating uniform target erosion, elimination of deep "V" grooves, and increased target utilization.

[0035] Figure 7A These are photographs of the prior art, showing copper plating and fading caused by embedded defects on a vacuum bellows made of stainless steel hydroformed for cryogenic particle accelerator applications and impurities in the plating solution.

[0036] Figure 7BBased on existing technologies, the regions in the cryogenic module of a large superconducting RF particle accelerator where high-purity PVD coatings may be used are depicted, namely the long axis, short bellows, long bellows, beamline section, SRF elliptical cavity, etc.

[0037] Figure 7C Based on existing technology, this paper illustrates RF power loss and heat dissipation due to the poor conductivity of electroplated copper, and shows the relationship between temperature rise and coating thickness in a low-temperature cooled vacuum bellows section for two different RRR values, highlighting the need for high-purity thin-film coatings.

[0038] Figure 7D These are prior art photographs showing embedded defects and impurities in the copper plating solution and their impact on stainless steel bellows.

[0039] Figure 7E This is an overview of the prior art regarding defect materials and sizes in typical electroplated copper used in particle accelerator applications, which contribute to lower RRR, surface defects that can lead to sparking and electron emission under high electric fields, and poor performance.

[0040] Figure 8A Descriptions of conventional DC sputtering, pulsed DC, conventional HiPIMS, and IMPULSE +Positive Kick TM Comparison between them;

[0041] Figure 8B It is an illustrative pulse waveform that highlights IMPULSE. +Positive Kick TM Specific characteristics, particularly the generation of a strong, high-current main negative pulse region with significant target sputtering and target material ionization, and PositiveKick. TM The voltage reversal ejects the plasma from the target magnetic field in the form of high-energy ions (short kick) and transfers the bulk plasma to the substrate (long kick) – the oscilloscope waveform shows Cu plasma achieving a peak current of 2kA within 20 microseconds, followed by a +200V positive pulse lasting 50 microseconds;

[0042] Figure 9A A schematic diagram of the first of the three stages during IMPULSE operation is shown—the ultrafast HiPIMS stage;

[0043] Figure 9B A schematic diagram of the second of the three phases during the IMPULSE operation is shown – the short kick phase;

[0044] Figure 9CA schematic diagram of the third of the three phases during the IMPULSE operation is shown—the long kick phase;

[0045] Figure 10 The use of IMPULSE without disrupting the vacuum, interrupting, or segmenting the process is described. +PositiveKick TM A schematic diagram of the continuous process;

[0046] Figure 11A It is depicted in expressing IMPULSE +Positive Kick TM Schematic diagram of the effect on a substrate with 3D or high aspect ratio features, including high-energy ion bombardment from the short kick phase, substrate immersion in bulk plasma expansion and subsequent quasi-conformal and ion bombardment from the long kick phase.

[0047] Figure 11B It is processed by Radial Magnetron TM +IMPULSE +Positive Kick TM Processed traditional W and Photographs of the high aspect ratio stainless steel bellows interface, which exhibits quasi-conformal Cu coverage, high strength and withstands low-temperature immersion, heat treatment, plastic deformation tension and cyclic fatigue without buckling, delamination or film failure.

[0048] Figure 11C Is using IMPULSE? +Positive Kick TM Photographs of HiPIMS etched and deposited insertable radial magnetrons coating the inner diameter of a stainless steel hydroformed bellows section.

[0049] Figure 11D yes Figure 11C Another photograph of the same bellows with the inner hole facing downwards highlights the uniformity of the coverage;

[0050] Figure 11E These are photographs of a destructive test performed on a wire EDM (wire-EDM) machine that cross-cuts a copper-plated film, showing... Figure 11C and 11D The bellows shown in the diagram provide continuous coverage without material failure.

[0051] Figure 12 Depicting with IMPULSE A high-level schematic diagram of the thin film deposition, etching, and surface modification system for the pulse module and power supply;

[0052] Figure 13A It is IMPULSE Photos of the pulse module and related power supply;

[0053] Figure 13B It is used in conjunction with / with IMPULSE A schematic diagram of a single radial magnetron in-line deposition system for surface modification, etching, and deposition of vacuum bellows and accelerator components by a pulse module / operation.

[0054] Figure 13C This is a schematic diagram of a multi-radial magnetron inline deposition system for surface modification, etching, and deposition of an example Cu cavity for superconducting coating. The superconducting coating is composed of more than one material, such as radial magnetron A and radial magnetron B.

[0055] Figure 14A It is a side view schematic diagram of a radial magnetron batch deposition system including a vacuum chamber, at least one radial magnetron, and at least one substrate mounting structure between the radial magnetron and the vacuum chamber, wherein the substrate is etched or deposited with plasma and materials generated at or near the radial magnetron.

[0056] Figure 14B This is a top-down schematic diagram of a radial magnetron batch deposition system, highlighting the placement of one or more radial magnetrons, multiple substrate mounting structures, auxiliary anodes, and the vacuum chamber boundary;

[0057] Figure 14C This is a side profile schematic of a radial magnetron batch deposition system, highlighting the exchange system used for inserting / removing multiple radial magnetrons, shielding caps, and auxiliary anodes;

[0058] Figure 15 This is a schematic diagram of a radial magnetron applied to a traditional inline transport substrate processing station, highlighting the IMPULSE. +Positive Kick TM Enhanced plasma transport to the substrate;

[0059] Figure 16A This is a schematic diagram of the application of a radial magnetron for inline roll-to-roll coating, wherein the substrate is transported relative to the radial magnetron and can be guided to a position close to the radial magnetron to achieve higher utilization efficiency.

[0060] Figure 16B The application of several radial magnetrons is further described to provide high-rate continuous roll-to-roll thin film deposition and potentially add auxiliary anode return electrodes for insulating or large-area substrates.

[0061] Figure 16CThe routing of the flexible substrate around the single radial magnetron is further described to maximize the use of sputtered material and to enable daisy-chain connection with additional radial magnetrons for multilayer coating and inline radial magnetron exchange.

[0062] Figure 17 An example structural region diagram with two independent axes, effective temperature (T*) and effective sputtered particle energy (E*), is illustrated and is available for IMPULSE. and Positive Kick TM To solve the problem. Detailed Implementation

[0063] The detailed description of the following figures should not be considered limiting, but is merely for the purpose of illustrating the principles of the described embodiments.

[0064] Traditional structures and systems used to manufacture superconducting radio frequency (SRF) accelerator systems involve using large blanks of special-grade materials or alloys (such as niobium, beryllium, or ultra-high purity oxygen-free copper) and precision machining to achieve the precise dimensional tolerances of the narrowband resonant cavities for RF acceleration. For many accelerator components, only a small fraction (i.e., a few percent) of the bulk material is used, resulting in significant losses of material, time, and labor. This comes at a great cost to maintaining material properties and minimizing defective interfaces, tolerance / stack errors, hermeticity interruptions, and mismatches. Typically, substrate materials are used for their superior structural properties, but at the expense of their electrical or thermal properties. Trade-offs include using stainless steel instead of copper, or conversely, choosing niobium instead of copper. Since electrical properties dominate the skin depth of electromagnetic propagation in high-frequency (e.g., MHz) materials, composite structures with surface layers exhibiting excellent electrical and vacuum properties are used. For wet chemical processes such as electroplating, challenges exist regarding coating thickness uniformity, impurities in the solution, sacrificial anodes, batch-to-batch non-manufacturability, and the purity of the material supply. This is particularly challenging for copper plating on stainless steel used at low temperatures to simply minimize resistive losses in vacuum systems, accelerator beamlines, and transmission tubes spanning hundreds of meters.

[0065] For composite material structures, different materials can be selected for different components to address thermal properties, structural support, expansion and contraction, shock absorption, and other factors. The ability to form composite material structures enables new methods for fabrication, alignment, fixing, and segmentation, helping to reduce costs and increase design flexibility, decrease weight, size, and power, and facilitate integration. In particular, desired surface material properties (e.g., low electron emission), material purity (e.g., low inclusions, low field concentration), cavity smoothness (e.g., lower field emission, higher gradient), near-surface morphology (e.g., limited whisker growth, spark initiation), and vacuum tolerance (e.g., low vapor pressure, surface mobility) can be designed to improve the characteristics of RF LINACs.

[0066] The manufacturing operations and techniques described herein also allow for the use of more robust, thermally conductive, and easier-to-form / process / operate materials; the use of thin layers for superconducting cavities instead of bulk, solid niobium materials; or the complete replacement of environmentally challenging wet chemical processes. This technology offers greater options and choices for accelerator cavities and components due to the diversity of materials that can be deposited on a range of substrates. Traditional wet chemical and electroplating techniques are limited by substrate material selection, substrate shape, contamination, surface finish, and adhesion strength. The innovative manufacturing features currently disclosed herein are based on the combination of conformal physical vapor deposition with surface etching, preparation, and modification techniques for a wide range of materials.

[0067] Physical vapor deposition (PVD) coatings can be customized to produce desired physical, thermal, and electronic properties, especially considering the new IMPULSE. +Positive Kick TM High-power pulsed magnetron sputtering (HiPIMS) technology offers precise ion energy control and improved deposition rates. See US 11,069,515 and related applications. However, PVD deposition on the inner diameter of small tubes or complex shapes (such as 3D bellows, elliptical SRF cavities, and beamforming elements) has been challenging due to limitations in the physical mounting of PVD sputtering hardware into space, providing sufficient uniformity, limiting dust / particles / arcs, and managing a variety of materials. Standard magnetron sputtering is accomplished using planar rectangular magnetrons for large-area depositions and planar circular magnetrons for small-area depositions. These systems typically achieve target utilization rates of 15–40% and are used in inline production for glass windows, solar panels, and semiconductor coatings. Improved target utilization rates are achieved by rotating a cylindrical target around a fixed planar rectangular magnetic field to increase utilization to 90% through directional sputtering processes (i.e., downward sputtering). However, these shapes are very limiting for precise coating on the internal dimensions of parts, especially for objects with a diameter of less than 0.5 meters.

[0068] The innovations in this disclosure specifically relate to a novel radial magnetron configuration that incorporates a geometry suitable for small-sized and relatively long cylindrical target materials, within which a movable permanent magnet structure is incorporated. This structure enables the movement of a localized target magnetic field around the target surface to generate a dense plasma region for etching and sputtering. The cylindrical shape is ideally suited for small diameters in small-ID coatings and has also been extended to larger diameters for high-volume coating applications.

[0069] The illustrative example described herein differs from the use of cylindrical magnetrons developed over 30 years ago, which employed a large set of external electromagnets to generate a uniform axial B-field volume to set the Hall current for sputtering. The radial magnetron of this disclosure uses a high-gradient (sharp-angled) field near the target surface, with internal permanent magnets to control and confine a dense plasma region suitable for HiPIMS operation. Target homogenization is achieved through rotational or axial displacement of the magnetic field. Furthermore, conventional cylindrical cathode magnetrons widely used in the semiconductor and web-coating industries employ physically rotating target electrodes with brushed contacts, which are unsuitable for the pulsed current handling capabilities of HiPIMS operation. Starfire's technology features hard metal contacts capable of handling currents far exceeding those typical for HiPIMS operation, enabling positive voltage reversal and rotation of the plasma region for homogenization. (Ultrafast IMPULSE) The technology can routinely drive current densities >10 A / cm² (more than 10 times that of standard HiPIMS), resulting in ionization rates >90% for directional iPVD. This characteristic is achieved using a rigid, high-current contact with a rotating / displacement permanent magnet assembly. Furthermore, particle generation is further minimized because there is no surface / component movement facing the vacuum; only the internal magnet assembly of the radial magnetron, which does not see a vacuum, is rotating or moving. This is crucial for many thin-film applications.

[0070] Accelerators are large and expensive, and are typically located in national laboratories, medical centers, and research universities. Direct sputtering coatings on the interior can seal interfaces between components such as blades, diaphragms, tuning rods, bellows, etc. However, the sputtering coating methods and structures described herein are widely applicable to a variety of applications beyond coating the internal surfaces of accelerator components. Examples include ID coatings for production pipes in oil and gas applications to resist corrosion and erosion, and coatings for gun barrels to enhance wear resistance. This disclosure can also be used for coating 3D turbine blades for thermal protection, coating 3D cutting tools with hardened layers, roll-to-roll coatings for polymer metallization, and coating inline glass substrates.

[0071] Figure 1AThe image shows a cross-section of such an exemplary radial magnetron. The illustrative example has all cooling, mechanical, and electrical connections at one end, allowing cylindrical components (e.g., bellows or tube sections) to be conveniently placed around the magnetron, as will be discussed later. Figure 13B As shown in the figure. In addition, it also employs a rotating internal magnet assembly, which has the following effects: 1) significantly improves the utilization rate of the target material; 2) minimizes the drift of operating parameters as the target material ages.

[0072] Figure 1A This is an axial schematic diagram applicable to a radial magnetron system incorporating the features of this disclosure. Figure 1A A schematic axial inward cross-sectional view of the endcap radial magnetron emitting ions and neutrons is depicted, highlighting the internal coolant flow, magnetic components, and plasma generation on the exterior. The sputtering target axial electrode 1001 is fitted with an internal cooling channel 1007 that allows coolant to flow through the individual permanent magnet materials (such as NdFeB or SmCo), encompassing and forming the main sputtering / etching permanent magnet assembly 1005. The sputtering target material 1013 is placed on the exterior of the axial electrode 1001. A magnetic substrate 1004 holder, flux yoke / shunting, and physical spacing between the individual permanent magnets may be present to form the main sputtering / etching permanent magnet assembly 1005. The main sputtering / etching permanent magnet assembly is configured to generate a Hall effect electron trapping region near the target material 1013 to generate and maintain a dense plasma region 1009 when a potential is applied to the axial electrode. Cooling fluid inlet 1007 and cooling fluid outlet 1008 provide a means of directly cooling the target material 1013 via the axial electrode 1001 and the main sputtering / etching permanent magnet assembly 1005. This is necessary to maintain the magnetic flux density of the target region's magnetic field to form a suitable plasma for sputtering and etching when a voltage is applied to the axial electrode 1001. The axial electrode 1001 can be hollow and pass through the vacuum chamber through two ports, or it can have an end cap 1002 at one end, making the radial magnetron a single-sided device that can be inserted into the vacuum chamber from one port. Furthermore, the main sputtering / etching permanent magnet assembly 1005 can be mounted to a structure that facilitates rotation or movement, such as an internal coolant channel 1003 or other such injection element. Rotation or movement of the magnet-target magnetic field is used to distribute a dense plasma region 1009 around the axial electrode 1001 to balance the erosion and removal of the target material 1013.

[0073] Figure 1B This is a cross-sectional schematic diagram of a radial magnetron system applicable to the features of this invention. Figure 1AIn the orthogonal cross-sectional view of the depicted structure, sputtering axial electrode 1001 is shown, with target material 1013 moving relative to the main sputtering / etching permanent magnet assembly 1005, highlighting the relative rotation. Magnet-target rotation 1012 allows the target region magnetic field 1011 from the magnetic material within the main sputtering / etching permanent magnet assembly 1005 to move relative to the target material 1013, causing the dense plasma region 1009 to shift around / along the circumference of the target material and generating a particle flux 1010 for processing a substrate 1030 (not shown). In the illustrative example, the main sputtering / etching permanent magnet assembly 1005 is mounted on a magnet substrate 1004 that holds the individual magnetic materials in one orientation to generate a Hall effect volume near the target material 1013, where the dense plasma region 1009 is formed. The dense plasma region 1009 generates a flux of high-energy ions and neutral particles 1010, which points outward from the sputtering target material 1013 toward the surface to be coated, etched, and modified.

[0074] Figure 1C This is a photograph of a radial magnetron system operating under IMPULSE+Positive Kick HiPIMS operation without magnetic rotation. The photograph depicts an embodiment of a 1.5-meter-long axial electrode 1001 with a magnetic field arranged to generate a single serpentine dense plasma region 1009 around a sputtering target material 1013. Electrons travel along a continuous serpentine track via a Hall effect ExB force (also known as the “magnetron effect”) generated by applying a voltage to the axial electrode 1001 of the sputtering target, resulting in the generation of a strong plasma region at the dense plasma region 1009. Because this is a single track, the plasma density can be balanced across the radial magnetron surface, resulting in better uniformity over its entire length. In this particular example, a 1.5-meter-long plasma region with good uniformity over its entire length is formed, suitable for azimuth rotation. Figure 1C Only an illustrative, non-limiting example of a single, continuous radial magnetron without end caps is shown, which can be supported across a vacuum chamber from both sides, with power injection at both sides to achieve greater power handling capacity.

[0075] Figure 1D This is a photograph of a radial magnetron system operating under IMPULSE+Positive Kick with magnetic rotation at similar etching process parameters. This is another embodiment in which the radial magnetron 1002 with end caps operates together with a single serpentine raceway dense plasma region 1009 on a sputtering target electrode 1013. Figure 7D In the middle, the radial magnetron 1002 with end caps adopts IMPULSE +Positive / Super KickTM The technology is used to generate electromagnetic fields for performing cleaning, etching, and surface modification—as demonstrated by the blue-pink-violet color of the etching-mode plasma 1014 on a copper sputtering target electrode (when viewed in actual operation). In this etching-mode plasma 1014, a radially capped magnetron 1002 generates high-energy Ar+ ions and directs them radially outward to clean the surface of the object to be treated (e.g., the high aspect ratio features of an accelerator cavity wall or a bellows).

[0076] Figure 1E This is a photograph of a radial magnetron system operating under magnetically rotating IMPULSE+Positive Kick with similar deposition process parameters. Advantageously, the IMPULSE can be changed in less than one second during surface preparation and processing operations. Operating parameters to switch the component's operation from performing cleaning / etching operations to deposition / implantation operations. Figure 1E yes Figure 1D The photograph shown is of the same system and uses the IMPULSE image. +Positive Kick TM The technology generates electromagnetic fields to perform injection, mixing, bonding, stress control, morphology control, diffusion barriers, and capping—as evidenced by the bright green copper plasma color of the plasma 1015 used for deposition mode from the sputtering target electrodes (when viewed in actual operation).

[0077] Figure 2A A cross-sectional view along the axis of a high-current radial magnetron system with an internally rotating master sputtering / etching permanent magnet assembly is depicted, which generates a moving target magnetic field coupled to an external magnetic actuator on the air side. The master sputtering / etching permanent magnet assembly 2005 is mounted on a magnet substrate 2004, which serves as an internal coolant channel from a cooling input pipe 2021 that generates an input flow 2007. A coolant transition or perforation 2006 facilitates flow redirection, allowing the flow to subsequently pass over the inner surface of the axial electrode 2001 while maintaining concentric orientation and allowing rotation of the master sputtering / etching permanent magnet assembly. Sputtering target material 2013 is fixed to the axial electrode 2001, and an end cap 2002 closes the unit if the radial magnetron 2029 is confirmed to be "end-type". The high-current return line 2023 is attached to the axial electrode, which features hard contacts and a high surface area to provide impulsive operation under pulsed conditions. +Positive Kick TMHiPIMS provides good conductivity. A secondary internal moving permanent magnet assembly 2017 is mounted on the magnet substrate 2004 to provide magnetic coupling to the primary sputtering / etching permanent magnet assembly 2005 via physical and / or magnetic connection. A secondary external moving permanent magnet assembly 2018 is placed outside the secondary internal moving permanent magnet assembly 2017 and isolated with insulating material sufficient to prevent high-voltage conditions near the high-current return line 2023. The secondary external moving permanent magnet assembly 2018 can be physically rotated by external actuation (such as a belt driver or a stepper motor with appropriate gears (not shown)) to rotate the magnetic assembly, thereby achieving the desired motion on the primary sputtering / etching permanent magnet assembly 2005. Similarly, the high-current return line 2023 provides robust pulsed current capability through the additional length of the axial electrode 2001 on the air side of the external isolation / vacuum seal 2020. The external isolation / support 2019 can be used to electrically isolate the primary sputtering / etching permanent magnet assembly 2005 from the secondary internal permanent magnet assembly 2017, and to allow for the manufacture of a separate component regardless of the length of the axial electrode 2001. It should be noted that the external isolation / vacuum seal 2020 can be used to secure the radial magnetron 2029 to a vacuum system for operation.

[0078] Figure 2B An illustrative solid model of a radial magnetron is depicted, featuring internal flow channels, a primary magnet placement on the vacuum side for sputtering / etching, a secondary magnet placement on the air side for independent magnetic rotation, a PTFE bushing for rotation, and an insulator. Similarly, a coolant inlet pipe 2021 feeds through a PTFE slotted sleeve 2016 into a secondary internal magnetic assembly 2017 fixed to a magnetic substrate 2004, and may also feed into an internal isolation / support 2019 for current isolation and / or coolant transition or perforation 2006. An axial electrode 2001 extends the entire length of the radial magnetron 2029 through an external isolation / vacuum seal 2020. Another embodiment (not shown) places the entire radial magnetron 2029 within a vacuum chamber having a protective layer or housing on the "air-side" component, and uses flexible cables and hoses for power and coolant.

[0079] Figure 2C It has IMPULSE +Positive Kick TM The rotating magnetic field of operation Figure 2B A photograph of a high-current radial magnetron system shown, used for sputter etching / deposition of copper. A dense plasma region 2009 rotates relative to the target material 2013, etching / depositing the material onto the substrate 2030 at a distance.

[0080] Figure 3A cross-sectional view is shown, in which the main sputtering / etching permanent magnet assembly partially surrounds the circumference of the radial magnetron, thereby confining the dense plasma region to a discrete region that moves under rotation and / or axial displacement. The main sputtering / etching permanent magnet assembly 3005 is divided into discrete individual magnetoplasm regions 3022 and is mounted on a common magnet substrate 3004 undergoing magnet-target rotation 3012. Within each individual magnetoplasm region 3022, a dense plasma region 3009 formed by the target region magnetic field 3011 sputters target material 3013 from the axial electrode 3001. By using smaller individual magnetoplasm regions 3022, the active plasma region formed by the sum of each dense plasma region 3009 can remain smaller relative to the surface area of ​​the target material 3013 and the axial electrode 3001. This is advantageous for several reasons—primarily because it enables the achievement of the plasma current density required for localized HiPIMS ionization, such as >0.3 A / cm², while satisfying the maximum thermal properties of the target material 3013, preventing melting or thermal shock. Alternatively, it allows for the deposition of larger objects with larger diameter radial magnetrons within thermal or power budgets. By using a smaller, individual magnetic plasma region 3022, the advantages of IMPULSE+Positive Kick HiPIMS can be achieved for many difficult-to-use materials or deposition configurations—while maintaining spatial homogeneity and the target utilization advantages derived from target rotation or axial displacement.

[0081] Figure 4A A schematic cross-sectional view along the axis of a high-current radial magnetron system with a vacuum-side main sputtering / etching permanent magnet assembly capable of axial displacement to generate a moving target magnetic field coupled to an air-side external magnetic actuator is depicted. The main sputtering / etching permanent magnet assembly 4005 is mounted to a magnet substrate 4004, which serves as an internal coolant channel from a cooling input pipe 4021 that generates an input flow 4007. A coolant transition or perforation 4006 facilitates fluid diversion, allowing the fluid to pass over the inner surface of the axial electrode 4001 while maintaining concentric orientation and allowing movement of the main sputtering / etching permanent magnet assembly through a slotted sleeve 4016. Sputtering target material 4013 is fixed to the axial electrode 4001, and an end cap 4002 closes the unit if the radial magnetron 4029 is confirmed to be "end-type". The high-current return line 4023 is attached to the axial electrode, which has hard contacts and a high surface area to provide impulsive operation under pulse conditions. +Positive Kick TMHiPIMS provides good conductivity. A secondary internal moving permanent magnet assembly 4017 is mounted on the magnet substrate 4004 to provide magnetic coupling to the primary sputtering / etching permanent magnet assembly 4005 via physical and / or magnetic connection. A secondary external moving permanent magnet assembly 4018 is placed outside the secondary internal moving permanent magnet assembly 4017 and isolated with insulating material sufficient to prevent high-voltage conditions near the high-current return line 4023. The secondary external moving permanent magnet assembly 4018 can be physically moved by external actuation (not shown) to move the magnetic components, thereby achieving the desired movement on the primary sputtering / etching permanent magnet assembly 4005. Similarly, the high-current return line 4023 provides robust pulsed current capability.

[0082] Figure 4B The axial displacement of the main sputtering / etching permanent magnet assembly in the radial magnetron is further described. This radial magnetron is configured for axial movement of the target magnetic field to generate a dense plasma region for sputtering and etching. A magnetoplasmic reference point 4024 on a component of the main sputtering / etching permanent magnet assembly 4005 facilitates the target magnetic field 4011, enabling the formation of a dense plasma region 4009 for sputtering and transferring material from the target material 4013 to a substrate (not shown). The axial-longitudinal magnet-plasma displacement 4025 is achieved by physically moving a component of the main sputtering / etching permanent magnet assembly 4005 to displace the target magnetic field 4011, which moves the dense plasma region 4009 to sputter and transfer material from the target material 4013. The axial magnet-plasma displacement 4025 serves to promote target uniformity, extended lifetime, stable process conditions, and high-power operation.

[0083] Figure 4C In Impulse +Positive Kick TM A photograph of a high-current radial magnetron operating below ground, employing a main sputtering / etching permanent magnet assembly capable of axial displacement. Here is a 6.3 mm diameter radial magnetron 4002 with end caps, featuring a main sputtering / etching permanent magnet assembly arranged to generate multiple dense plasma regions 4009 around a sputtering target electrode 4013, which can be axially translated 4025. This configuration is suitable for processing the inner surfaces of structures with very small diameters and for coating the interiors of tubes and hard-to-reach locations. The radial magnetron has hard electrical contacts with a pulsed power module to maintain strong pulsed currents for HiPIMS and ionized PVD, as well as a Positive Kick function. Although Figure 4C A system with a very small diameter is shown, but the radial magnetron can be scaled up to a larger diameter to handle larger items while modifying the main sputtering / etching permanent magnet assembly.

[0084] Figure 5A This is an illustrative example of the construction of a large radial magnetron with an axial cylindrical electrode having multiple outward-facing target material portions for sputtering / etching long substrates. Here, the axial electrode 5001 material is bonded to the target material 5013 via a segmented target structure 5026. Individual segmented joints have customized target overlap areas 5027 to minimize seams and achieve better uniformity in target operation and sputtering.

[0085] Figure 5B This photograph highlights the use of a heat-shrink fitting assembly technique to bond a segmented niobium target to a copper axial electrode. Here, the axial electrode 5001 material can be a highly expandable, highly conductive material, such as copper, and it is bonded to the target material 5013, such as niobium, using a segmented target structure 5026. The axial electrode is cooled in a cold bath, for example, liquid nitrogen, and then the segmented target structure 5026 is continuously shrink-fitted on top for bonding. This produces a robust joint with good thermal contact for operation.

[0086] Figure 5C This is a photograph of an electrode, one meter long, attached to a radial magnetron target, before assembly with internal magnetic components and a coolant flow structure. Alternative embodiments include using axial electrodes as the target material, using elastomers or indium bonding media, brazing, etc. Furthermore, conventional cylindrical rotating cathode structures using cold spraying, atmospheric plasma spraying, and other sintering / pressing techniques are also suitable.

[0087] Figure 6A The formation of a deep "V" groove on the sputtered target material surface is illustrated in the absence of magnet-target rotation. The sputtering V-groove 6033 is highlighted, formed by the erosion of the target material 6013 by the impact of dense plasma 6009 on the sputtering region 6032. This results in the sputter distribution 6034 escaping only partially through the sputtering V-groove 6033, leading to a sputter emission angle 6035. Over time, this effect limits the particle flux 6010 to the substrate (not shown) to be coated. The magnetic flux density increases within the target material 6013 closer to the main sputtering / etching permanent magnet assembly (not shown), promoting greater ionization and erosion, resulting in a deeper sputtering V-groove 6033 and consequently a shorter target lifetime. The deeper the sputtering V-groove 6033, the smaller the solid angle of material escape and the higher the amount of material recovery that occurs, reducing the overall deposition efficiency of the system. For multiple runways, some may have deeper runway grooves than others. This speeds up maintenance cycles.

[0088] Figure 6BThis is a photograph of a radial magnetron after operation without magnet-target rotation, showing deep "runway" patterns of target erosion and inhomogeneity.

[0089] Figure 6C The illustration depicts a more uniform target material erosion pattern on the target surface, resulting from the magnet-target rotation (relative motion between the dense plasma region and the sputtered target material) and the minimization of the sputtering V-groove 6033 to the axial target edge, leading to better utilization and process uniformity. It should be noted that the sputtering emission angle 6035 is significantly larger with an approximately normal sputtering distribution 6034. This not only greatly improves target utilization but also ensures more stable plasma operating conditions as the target ages, as the erosion does not wear increasingly deeper grooves into the target.

[0090] Figure 6D This is a photograph of a radial magnetron after operation with the magnet and target rotating, showing a uniform target erosion profile 6036, elimination of deep "V" grooves, and increased target utilization. (Comparison) Figure 6B and Figure 6D This demonstrates the relative differences of the present invention in terms of erosion pattern and practicality. Improved uniformity and sputtering V-groove 6033 can be achieved by adjusting the rotation or axial direction of the magnetic field relative to the target, resulting in a larger solid angle emission and target utilization.

[0091] Figure 7A These are photographs of existing technology showing fading of copper plating, including for low-temperature particle accelerator applications, caused by embedded defects and impurities from the plating solution in stainless steel hydroformed vacuum bellows. Figure 7A This is an example of a bellows structure, which uses existing techniques for surface treatment / forming of stainless steel low-temperature bellows used in RF accelerators via electroplating. Figure 7A The images provided show inconsistent copper plating quality, and due to difficulties in masking and nickel impact layering, plating material could not be deposited on the sidewalls of the vacuum bellows section. The deposition / sputtering operation of this disclosure can replace existing methods, resulting in better surface treatment / electroplating outcomes.

[0092] Figure 7B Based on existing technologies, the regions in the cryogenic module of a large superconducting RF particle accelerator where high-purity PVD coatings may be used are depicted, namely the long axis, short bellows, long bellows, beamline section, SRF elliptical cavity, etc. Figure 7B An exemplary arrangement of a superconducting RF accelerator section, comprising multiple spools, bellows, and RF cavities requiring specific material properties, is depicted in the prior art. This disclosure relates to multiple sections with broad applications.

[0093] The radial magnetron disclosed in this paper enables conformal coating on accelerator surfaces, including RF cavities, RF seals, bellows and actual blade tips, IH structures, dielectric load structures, tuning elements, and electrodes. Impulse is tuned for a given radial magnetron configuration. +Positive Kick TM The properties of the material can be tuned around the Thornton / Anders structural region map to achieve different electrical, thermal, grain structure, mechanical, and stoichiometric / composition properties. For accelerator requirements, properties such as secondary electron emission, smoothness, and high-field emission limiting materials can be deposited and well-adheded at high-stress locations, while high-conductivity bulk materials can be coated in regions requiring low resistance. High-quality copper with high RRR can be obtained for spools, straight sections, and bellows. Similarly, for SRF cavities, a preferred-oriented Cu substrate can be deposited with a thin insulating NbN layer, with the main Nb coating on top, to optimize superconductivity. Radial magnetrons can have other combinations, materials, composite structures, and locations. For linear electron beam cavities, the leading-edge disk aperture is coated with one type of coating for high-field regions, and the cavity region is coated with different types of film structures. For example, ultra-smooth, nanocrystalline, or amorphous high-gradient materials on blade tips, and preferred-oriented high-conductivity copper in the cavity region.

[0094] Figure 7C Based on existing technology, this paper illustrates RF power loss and heat dissipation due to the poor conductivity of electroplated copper, shows the relationship between temperature rise and coating thickness in a cryogenically cooled vacuum bellows section for two different RRR values, and highlights the need for coating high-purity thin films. Figure 7C This paper illustratively describes the performance properties of existing technologies, demonstrating RF power loss and heat dissipation due to the poor conductivity of electroplated copper. The film thickness determines both the magnitude of RF loss and the structure's ability to conduct deposited thermal energy outwards. This is important not only for accelerator cavities but also for bellows sections, transmission tubes, and other beam structures. Notch-filter RF modes are heat sources present in accelerator structures such as bellows. For cold-deposited modules in superconducting accelerators maintained at liquid He temperatures, any thermal energy deposited here will be removed solely through conduction along the bellows surface to its edges. Thickness is crucial for these applications to minimize heating. A near-pure copper film (e.g., high RRR). Starfire's Impulse +PositiveKick TM The technology addresses this issue by enabling stress control within the deposited film. This allows process engineers to deposit films with little or no internal stress, which is crucial for thick, large-area films.

[0095] Figure 7D These are prior art photographs of structures including embedded defects and impurities in the copper plating solution, as well as their impact on stainless steel bellows. Surfaces treated according to prior art exhibit surface defects, corrosion, trapped material, inclusions, and surface roughness in conventional copper plating, leading to poor accelerator performance. +Positive Kick TM and Super Kick TM Pattern control allows for net deposition, etching, or simultaneous smoothing / roughness filling. Re-smoothing the surface is beneficial for high-gradient (i.e., spark-resistant or resistant) accelerator films. Initial spark resistance results in smoothness, but overall tolerances stem more from the absence of inclusions provided by depositing controlled films in an atom-by-atom process rather than batch casting and machining. After the initial smoothing, localized surfaces will no longer be smooth. Therefore, film impurities / defects / inclusions determine the properties of the post-processed surface.

[0096] Figure 7E This is a priori overview of the defective materials and dimensions in typical electroplated copper used in particle accelerator applications, which contribute to lower RRR, surface defects that can lead to sparking and electron emission under high electric fields, and poor performance. Figure 7E This is an illustrative overview of the properties of surfaces treated according to existing techniques. This overview illustrates the presence of inclusions in electroplated copper through size and material impurities. According to this disclosure, the surface treatments and formation operations and structures described herein enable control of material deposition on an atom-by-atom basis, greatly limiting the size and composition of inclusions, thereby suppressing local field enhancement, secondary electron multiplication, and sparks.

[0097] The illustrative examples presented use conformal ionization physical vapor deposition to replace wet chemical plating (e.g., Cu) for stainless steel bellows and specialized vacuum components used in accelerator structures. Wet chemical plating is being phased out due to its destructive environmental impact, handling of hazardous chemicals, high costs, and a lack of experienced businesspeople in the field. In the EU, recommendations and timelines for the complete phasing out of all plating have been proposed in the coming years, making investment in alternative technologies crucial. Known problems include: surface finish / roughness (including visible streaks in the plating layer), inclusions, particles from the plating itself, and particles that may be introduced during plating or subsequent surface smoothing steps (e.g., molybdenum polishing or shot peening).

[0098] Figure 8AThe text illustratively describes conventional DC magnetron sputtering (low current, low ionization), pulsed DC (low current, low ionization but more suitable for reactive gases), conventional HiPIMS (high current, high ionization but low deposition rate), and IMPULSE. +Positive Kick TM A comparison of (higher current, higher ionization rate, and higher deposition rate). Typically, the HiPIMS plasma current density is approximately 0.3 A / cm². 2 The ultrafast pulse following the Positive Kick pulse can exceed 3 A / cm. 2 It has good film properties and is used as a factor in designing reverse magnetron structures to obtain higher peak power for stronger ionization, conformal plasma etching, and deposition.

[0099] Figure 8B It is the illustrative pulse waveform 8040, which highlights IMPULSE. +Positive Kick TM Specific characteristics, particularly the region of strong large main pulse current 8041 and main pulse negative voltage 8042 that generates significant target sputtering and target ionization, and the Positive Kick TM The inversion of voltage 8045 ejects plasma from the target magnetic field in the form of high-energy ions (short kick 8043) and transfers bulk plasma to the substrate (long kick 8044)—the oscilloscope waveform shows Cu plasma achieving a peak current of 2kA within 20 microseconds, followed by a +200V positive pulse lasting 50 microseconds. Ultrafast IMPULSE The technology can routinely drive current densities >10 A / cm² (more than 10 times that of standard HiPIMS), resulting in an ionization rate >90% for directional iPVD. The extremely high current magnitude necessitates hard electrical contact with the physical area where the pulsed current propagates. The radial magnetron features fixed axial electrodes with a high surface area for hard metal contact, capable of handling IMPULSE pulsed currents. Figure 2A and Figure 4A The radial magnetron in the diagram shows the enabled hard, high-current contact 4023. Furthermore, particle generation is further minimized due to the fact that there is no movement of the vacuum-facing surface / component; only the internal magnet assembly of the radial magnetron, which does not see a vacuum, is rotating or moving.

[0100] Continue to refer to Figure 8BAdditional details are provided on oscilloscope waveform 8040, including Cu sputtering plasma achieving a peak current of 2 kA within 20 microseconds during the ultrafast HiPIMS phase, where the subsequent +200V positive pulse shows short-kick and long-kick phases. Voltage waveform 8042 and current waveform 8041 for the -750V, 2kA peak current HiPIMS pulse achieve a plasma current density of 5 A / cm² on a cylindrical magnetron of a copper sputtering target with a positive kick pulse of +200V, 125A peak current (highlighting short-kick 8043 and long-kick 8044). The technology drives plasma generation at high dI / dt to achieve rapid ionization for subsequent voltage reversal and positive kick. TM This accelerates the entry of ions and plasma into the substrate, enabling excellent cleaning, etching, preferred orientation deposition, and deposition with stress and morphology control. As taught in US20180358213A1, this technique also allows for synchronization with a pulsed DC bias power supply for time-window acceleration into the substrate for additional control.

[0101] Depending on local factors such as pre-ionization, target material, magnetic field, pressure, geometric curvature, sputtering gas, surface chemistry, and adsorbed gas, the main negative pulse on voltage waveform 8042 typically ranges from -400V to -1200V. Using an ultrafast switching topology, the typical high-current pulse width is less than 100 µsc, with a typical range of 20-50 µsc. Positive Kick on voltage waveform 8045 TM The amplitude is typically in the range of +0-600V. For users who do not want short-kick ion clusters to be accelerated away from the sputtering target (as shown in the current waveform for short-kick 8043), the onset delay of the positive kick will be set after this time period, which is typically set to 20-40 µsec. The ionization rate and plasma density near the sputtering target are highly coupled with the effective current density. Depending on the material, the effective current density is typically in the range of 0.1-10 A / cm². 2 Within the range.

[0102] One aspect of this disclosure is the ability to control the flux and energy of ions deposited / impacted onto a substrate during operation of the apparatus described herein in order to prepare and deposit thin films with engineered properties. Figure 9A A schematic diagram of the first of the three stages during IMPULSE operation is shown – the ultrafast HiPIMS stage. Figure 9A Adapted from U.S. Patent Application Publication US20180358213A1, and illustratively depicts ultrafast high-power pulsed magnetron sputtering and the potential distribution between the sputtering target and the substrate.

[0103] Figure 9B Depicting in A diagram illustrating the second of the three phases during the operation – the short kick phase. Figure 9B Adapted from US20180358213A1, it illustratively describes the ultrafast switching and positive voltage reversal on the target electrode, as well as the evolution of the potential distribution across the magnetically confined region near the target electrode—short-kick accelerated ions moving away from the target electrode from the dense HiPIMS plasma region, typically perpendicular to the magnetic field lines.

[0104] Figure 9C Depicting in A diagram illustrating the third of the three phases during the operation – the long kick phase. Figure 9C Adapted from US20180358213A1, it illustratively describes the evolution of the positive potential to the long kick stage, where the bulk plasma potential increases and a conformal sheath is formed on the substrate and other surfaces where the bulk plasma is exchanged.

[0105] By combining ultrafast high-current pulses with rapid positive voltage inversion and cylindrical magnetron configurations, a high level of customization is achieved, enabling outstanding new thin films, including advanced nanolayer composites and functionally graded materials with specific properties, such as high electrical gradient spacing, high voltage tolerance, high conductivity, ultra-smooth surfaces, oxidation resistance, thermal fracture toughness, crack resistance, diffusion barriers, and wear resistance, corrosion resistance, toughness and stiffness, and lubrication properties. Specifically, the deposition of superconductor-insulator-superconductor layers with low overall temperatures is highly sought after by engineers in superconducting wires, magnetic tapes, RF cavities, and accelerators.

[0106] Figure 10 The use of IMPULSE without disrupting the vacuum, interrupting, or segmenting the process is described. +PositiveKick TM A schematic diagram of the continuous process of adjusting IMPULSE parameter 10054. This is important in terms of the interface quality and cleanliness of substrate 10030. At a base pressure of 2e-6 Torr (typical base pressure for high vacuum systems), a monolayer of atoms will roughly cover the surface within 1 second. Minimal pauses are required from cleaning to etching to implantation to bulk deposition, significantly improving the fidelity of coating and surface modification. Core advantages are achieved in combining cleaning 10046, etching 10047, ion implantation 10048, adhesion control 10049, stress management 10050, bulk material deposition 10051, diffusion barrier or insulating layer 10052, and reactive / capping layer 10053 deposition. Ultrafast IMPULSE with positive voltage reversal is achieved through precise ion energy control. It can remove surface contaminants, etch near-surface damage, and gradually form a hybrid interface for a good adhesion layer to support one or more stress control layers, thereby enabling the overall film to grow together with one or more capping layers through a suitable interface.

[0107] Figure 11A It is depicted in expressing IMPULSE +Positive Kick TM Schematic illustrations of the effects on substrates with 3D or high aspect ratio features, including high-energy ion bombardment from the short-kick phase, substrate immersion in bulk plasma expansion, and subsequent quasi-conformal and long-kick phase ion bombardment. Using the radial magnetron configuration discussed herein, IMPULSE Ultrafast high-power pulsed magnetron sputtering (HiPIMS) technology can be used to generate dense metallic plasmas and perform ultrafast voltage inversion to execute positive kicks. TM and Super Kick TM The technology allows ions and plasma to be accelerated onto the substrate for modification. Figure 11A Depicting the use of IMPULSE +Positive Kick TM An illustration of an example of conformal coating on a substrate. During HiPIMS pulses, the current can be 10-1000 times higher than that of conventional DC sputtering. Combined with ultrafast IMPULSE... Pulse technology can achieve This results in a peak power density, thus producing a very high plasma density. (Positive Kick) TM Voltage reversal and positive bias push ions and plasma away from the dense magnetic field region on the magnetron to increase the local plasma density near the substrate during the pulse. This high-density bulk plasma expansion from the positive kick 11056 will have a shorter Debye length, which allows the 3D structured plasma to penetrate 11059 to the substrate 11030. Applying the positive kick initially accelerates ions from the magnetically confined region, whose orientation energy 11055 follows gradient B, and eventually causes the bulk plasma potential to rise, so that a conformal sheath 11057 will appear around the substrate 11030 and accelerate additional ions 11058 to reach the substrate. If the feature is larger than several Debye lengths, conformal deposition will occur. Another result of the positive kick is the improved ion trapping efficiency, which is important from an economic perspective.

[0108] Figure 11B Using Radial Magnetron TM +IMPULSE +Positive Kick TMProcessed traditional W and A photograph of a high aspect ratio stainless steel bellows section exhibiting quasi-conformal Cu coating, demonstrating high strength and withstanding cryogenic impregnation, heat treatment, plastic deformation tensile testing, and cyclic fatigue without buckling, delamination, or film failure, is presented as a replacement for conventional electroplating and wet electrochemical processes for stainless steel cryogenic accelerator bellows. In the foreground, the bellows structure specimen 11060 to be coated is made of hydroformed stainless steel suitable for cryogenic applications. The received material is inserted into a cylindrical magnetron system and impulse is applied. Positive Kick TM Used for bonding and surface adsorption atomic mobility, and Super Kick TM Used for etching / cleaning. Continuous thin / thick films are conformally formed deep within the high aspect ratio feature 11061 that forms the bellows expansion channel. Adhesion and film quality are sufficient to withstand... Air baking and immediate immersion in LN2 do not result in peeling, delamination, or material failure. The material is cycled through >1000 full-range expansion-compression strokes without causing membrane failure.

[0109] Figure 11C Is using IMPULSE? +Positive Kick TM Photograph of HiPIMS etched and deposited insertable radial magnetron coated on the inner diameter of stainless steel hydroformed bellows section 11062. Figure 11D yes Figure 11A Another photograph of the inner bore 11063 of the same corrugated pipe highlights the uniformity of the coverage. Figure 11E These are photographs of a destructive test performed on a wire EDM machine during the cross-section cutting of a copper-plated film, showing continuous coverage without material failure. Radial magnetron +IMPULSE +Positive Kick TM Reliability was demonstrated by performing in-situ cleaning / etching and shallow injection to achieve excellent film adhesion. A wire EDM machine is required to perform a cross-section cut on the 11061 to inspect the film's properties and cross-section, as it cannot be separated from the stainless steel substrate without damaging the part.

[0110] This disclosure allows for the achievement of very thick, stress-controlled, fully dense, highly conductive, and well-bonded coatings to address bellows and SRF challenges. Low-temperature deposition using PositiveKick and IMPUSLE allows for higher effective T* and E*, resulting in correct orientation, without higher overall temperatures leading to interlayer interdiffusion. The addition of a knob for the start-up voltage / duration is meaningful. T* on the Thornton zone map can be changed without directly heating the substrate. Lower actual substrate temperatures prevent diffusion in nanolayer materials (e.g., SIS structures). For low-defect applications, tunable surface mobility is crucial for SC films.

[0111] Figure 12 Depicting with IMPULSE A high-level schematic diagram of the thin film deposition, etching, and surface modification system for the pulse module and power supply. Figure 12 This is a schematic block diagram illustrating a sputtering target electrode, a return electrode, a substrate, plasma in a vacuum environment, and one or more [elements not specified]. Pulse module (its main power supply and reverse power supply) and any An illustrative example of the electrical component / circuit arrangement between the bias pulse module power supplies. Figure 12 The schematic diagram in the image outlines the methods used for deposition and etching. System general setup. High-voltage electrical pulses are directly supplied to the sputtering target from an external pulsed power module via appropriate insulation and low-impedance connections. This allows for low-impedance electrical connection with the sputtering target support via a rotating magnetic assembly, enabling efficient power transfer and coupling. The module is designed for both parallel synchronous and asynchronous operation. Therefore, multiple units can pulse in parallel, delivering the required power, rise time, and plasma density to the sputtering target electrode configuration.

[0112] The following shows a typical radial magnetron system setup. Figure 13A It is IMPULSE Photos of the pulse module and related power supply. Figure 13B It is for use with IMPULSE A schematic diagram of a single radial magnetron inline deposition system 13064 for surface modification, etching, and deposition of vacuum bellows and accelerator components. Figure 13C This is a schematic diagram of a multi-radial magnetron inline deposition system 13065 for surface modification, etching, and deposition of an example Cu cavity for superconducting coating. The superconducting coating is composed of more than one material, such as radial magnetron A and radial magnetron B. The schematic diagram reflects additional details specific to the radial magnetron arrangement type (single, multiple, end cap, through, etc.). Figure 12 .for Figure 13CEspecially for multiple radial magnetrons, one radial magnetron can be primarily used for the initial substrate cleaning and etching steps to collect the etched / removed material. Additional methods for removing non-volatile impurities include embedding them in the chamber walls, sacrificial anodes, or other electrodes, or allowing the impurities to fall onto the inactive areas of the etched radial magnetron and be buried during the deposition steps. Figure 13C In the example configuration highlighted in the diagram, a copper radial magnetron is able to deposit a clean, pure interface layer on the substrate to produce known electrical, physical, and morphological properties (such as a preferred Cu orientation for growing Nb thereon), and then a second radial magnetron is able to deposit a niobium or nitride layer, such as NbN, for superconducting properties. This illustrates the coating of the SRF cavity.

[0113] Beyond simple inline systems that extend the processing range to coating cavities, bellows, or sleeves / pipes, radial magnetrons can be extended for batch coating applications. Figure 14A A schematic side profile of a radial magnetron batch deposition system 14066 is shown, comprising a vacuum chamber 14068, at least one radial magnetron 14029, and at least one substrate mounting structure 14067 between the radial magnetron and the vacuum chamber. The substrate 14030 is used for etching or deposition of plasma and material generated at or near the radial magnetron 14029, resulting in 14010. A key advantage of the radial magnetron batch deposition system 14066 is that one or more target material sources can be interspersed within the substrate 14030 and the mounting structure 14067 to achieve greater target utilization. The vacuum chamber wall 14068 can be located away from the mounting structure 14067 and the substrate 14030, minimizing the specific debris 14077 formed after repeated deposition and degassing cycles on the batch deposition machine. This is an additional benefit compared to conventional batch deposition machines employing planar magnetrons and rotating cylindrical magnetrons on the outer wall of the container. The substrate is typically located near the wall, where particulate debris 14077 can accumulate.

[0114] Figure 14B This is a schematic diagram of a radial magnetron batch deposition system 14066, highlighting the placement of one or more radial magnetrons 14029, multiple substrate mounting structures 14067, auxiliary anodes 14069, and vacuum chamber boundaries 14068.

[0115] Figure 14CThis is a side profile schematic of the radial magnetron batch deposition system 14066, highlighting the exchange system 14070 for inserting / removing multiple radial magnetrons 14029, shielding caps 14074, and auxiliary anodes 14069. The shielding caps 14074 serve two purposes: protecting one magnetron target material in the presence of another, and for anode current recirculation in ambient plasma or potential bias. The radial magnetron batch deposition system 14066 enables large-volume batch processing of the multiplexed substrate mounting structure 14067 to handle large-volume substrates 14030. (With IMPULSE) +Positive Kick TM When combined, the bulk plasma generated by the coordinated operation of multiple radial magnetrons can lead to enhanced plasma immersion, enabling near-conformal deposition and etching.

[0116] Figure 15 This is a schematic diagram of a radial magnetron applied to a traditional inline transport substrate processing station, highlighting the IMPULSE. +Positive Kick TM Enhanced plasma transport to the substrate. A radial magnetron 15029 is placed on an inline transport device of a substrate 15076 with discrete transport. (This is due to its origin from IMPULSE.) The high ionization rate caused by the operation allows a portion of the particle flux 15010 to be guided 15077 toward the discrete transport substrate 15076 by appropriate electric field orientation, bias, and vacuum chamber ground plane position.

[0117] Figure 16A This is a schematic diagram illustrating the application of radial magnetrons for inline roll-to-roll coating, wherein the substrate is transported relative to the radial magnetron and can be guided close to the radial magnetron to achieve higher utilization efficiency. Figure 16A In this configuration, a radial magnetron 16029 is located between roll-to-roll substrate systems 16071 that guide substrate 16030 along a roll-to-roll coating machine path 16075. Movement 16072 approaches the radial magnetron 16029 to guide particle flux 16010 onto substrate 16030 to produce surface modification and thin film coating 16031.

[0118] Figure 16B The application of multiple radial magnetrons 16029 is further described to provide high-rate continuous roll-to-roll thin film deposition 16031, and potentially an auxiliary anode 16070 return electrode is added for insulating or large-area substrates.

[0119] Figure 16CThe roll-to-roll coating path 16075, which routes around a single radial magnetron 16029 to a flexible substrate 16030, is further described to maximize the use of sputtered material and to be daisy-chained with additional radial magnetrons for multilayer coating and inline radial magnetron exchange. Figure 16C The system shown can be extended to more radial magnetrons for large-scale printing and coating applications of thin films such as plastics, glass, and metals.

[0120] Figure 17 An example structural region diagram with two independent axes, effective temperature (T*) and effective sputtered particle energy (E*), is illustrated and is available for IMPULSE. and Positive Kick TM Let's solve it. Figure 17 This is an illustration of the Thornton structure region diagram for generalized energy condensation, improved by Andre-Anders, which expands the control over the microstructure and morphology of thin films. Adjustments to the HiPIMS pulse amplitude, pulse width, timing, peak current density, repetition rate, and pressure for a given substrate-to-sputter target distance, magnetic field geometry, and magnetic field distribution allow control of the main pulse particle flux (T*) to approximate a thermal spike. Stronger short pulses with higher particle loading over shorter durations exhibit a high-temperature effect, allowing the deposited material to reach equilibrium and be tuned towards fibrous transition grains (region T), columnar grains (region 2), and recrystallized grain structures (region 3). For a given magnetic field, cusp magnetic null geometry, pressure, and main pulse... The available plasma generated by the pulse, through adjustments to the positive kick pulse amplitude, short / long kick pulses, onset delay, and any super-kick effect used for similar RF oscillations, will allow for tuning of the effective energy (E*) and, consequently, the microstructure and morphology of the thin film. This essentially controls... The positive kick allows for movement across the entire Anders / Thornton SZD, even enabling the production of fine-grained nanocrystalline films with preferred orientations and regions for low-temperature, low-energy ion-assisted epitaxial growth, as well as dense amorphous glass films. Process engineers can move around the SZD to achieve tensile / compressive stress control, the relationship between columnar growth and nanocrystals with preferred orientations, etc.

[0121] Given that the principles of this disclosure can be applied to many possible embodiments, it should be understood that the examples described herein with reference to the accompanying drawings are merely illustrative and should not be considered as limiting the scope of this disclosure. For example, those skilled in the art will recognize that the elements of the illustrative examples depicted as functional blocks and in the depicted structures can be implemented in a wide variety of electronic circuits and physical structures as understood by those skilled in the art. Therefore, modifications in arrangement and detail are possible in the illustrative examples without departing from the spirit of the invention. Thus, the invention as described herein contemplates all such embodiments falling within the scope of the following claims and their equivalents.

[0122] All references cited in this article, including publications, patent applications and patents, are incorporated herein by reference to the same extent that each reference is individually and explicitly cited and fully elaborated in this article.

[0123] The terms “a,” “an,” and “the,” and similar pronouns used in the context of describing this invention (particularly in the context of the following claims) should be interpreted to cover both singular and plural forms, unless otherwise stated herein or clearly contradicted by the context. Unless otherwise stated, the terms “comprising,” “having,” “including,” and “containing” should be interpreted as open-ended terms (i.e., meaning “including but not limited to”). Unless otherwise stated herein, descriptions of numerical ranges herein are intended only as a shorthand method of individually referring to each individual value within the range, and each individual value is incorporated into the specification as if it were individually described herein. Unless otherwise stated herein or clearly contradicted by the context, all methods described herein may be performed in any suitable order. The use of any and all example or exemplary language (e.g., “such as”) provided herein is intended only to better illustrate the invention and does not constitute a limitation on the scope of the invention unless otherwise required. No language in the specification should be construed as indicating that any element not protected by the claims is essential to the implementation of the invention.

[0124] Exemplary embodiments are described herein as embodiments known to the inventors for carrying out the invention. Variations of these embodiments will be apparent to those skilled in the art upon reading the foregoing description. The inventors expect those skilled in the art to appropriately employ such variations, and the inventors intend to practice the invention in ways different from those specifically described herein. Therefore, the invention includes all modifications and equivalents of the subject matter described in the appended claims as permitted by applicable law. Furthermore, unless otherwise indicated herein or otherwise clearly contradicted by the context, any combination of the foregoing elements in all possible variations is included in the invention.

Claims

1. A radial magnetron system for plasma surface modification and high-quality film deposition of multidimensional structures, the radial magnetron comprising: Axial electrode; Target material, said target material being disposed on a portion of the axial electrode; The applied potential from an external power source; High-current contact, which is attached to the axial electrode for the applied potential; A main permanent magnet assembly, comprising various magnetic material elements configured to generate a target magnetic field for generating a Hall effect dense plasma region when the applied potential is applied to the axial electrode. A magnet substrate that supports the main permanent magnet assembly within the axial electrode. The magnet substrate is configured to provide channels for cooling the main permanent magnet assembly and the axial electrode. The system further includes a secondary internal permanent magnet assembly and a secondary external permanent magnet assembly. The secondary internal permanent magnet assembly is coupled to the magnet substrate to provide magnetic coupling to the primary permanent magnet assembly via physical and / or magnetic connection. The secondary internal permanent magnet assembly is further configured to allow motion to be applied from the secondary external permanent magnet assembly, which is placed outside the secondary internal permanent magnet assembly and physically rotated by external actuation to rotate the secondary internal permanent magnet assembly, thereby achieving the desired motion of the main permanent magnet assembly.

2. The system according to claim 1, wherein, The system further includes at least one slotted sleeve that maintains the concentric orientation of the main permanent magnet assembly relative to the axial electrode.

3. The system according to claim 1, wherein, The magnet substrate is configured to allow rotation of the main permanent magnet assembly.

4. The system according to claim 1, wherein, The magnet substrate is configured to allow axial-longitudinal displacement of the main permanent magnet assembly.

5. The system according to claim 1, wherein, The system further includes an isolation support configured to isolate the primary permanent magnet assembly from the secondary internal permanent magnet assembly current.

6. The system of claim 1, further comprising an end cap, wherein the end cap is configured to rotatably support the magnet substrate.

7. The system of claim 1 further includes an end cap, wherein the end cap is configured to receive a coolant return channel.

8. The system according to claim 1, wherein, The axial electrode is essentially a hollow cylindrical container.

9. The system according to claim 1, wherein, The main permanent magnet assembly includes discrete permanent magnet magnetic field sources separated by gaps along the outer periphery of the axial electrode.

10. The system according to claim 3, wherein, The system supports in-process rotation of the main permanent magnet assembly.

11. The system according to claim 4, wherein, The system supports in-process axial-longitudinal displacement of the main permanent magnet assembly.

12. The system according to claim 1, wherein, The external power supply also includes field-generating electronic circuitry, which is configured to perform: High-power pulsed plasma magnetron discharge is generated by applying a large current negative direct current (DC) pulse to the axial electrode, and After terminating the negative DC pulse, a configurable continuous positive voltage kick pulse is generated and supplied to the axial electrode. and The logic circuit configured by the program processor issues a control signal to control at least one kick pulse attribute of the configurable continuous positive voltage kick pulse, the kick pulse attribute being taken from a group consisting of a start delay, duration, amplitude, and frequency including its modulation.

13. The system according to claim 12, wherein, The system is configured to modify a surface by material etching and material deposition during a single continuous production process.

14. The system according to claim 1, further comprising: Vacuum chamber, gas management, pumping, fixtures for holding the substrate to be coated relative to the radial magnetron, thermal management system, and control electronics.

15. The system of claim 14, further comprising: An actuator is used to influence the position of the radial magnetron relative to the vacuum chamber.

16. A batch coating system for depositing high-quality films on multiple surface-treated structures, the system comprising: Vacuum chamber assembly, including vacuum chamber, gas management system and vacuum pumping system; Radial magnetron, including target material; External power supply, and Mounting structure for holding multiple surface treatment structures; The mounting structure is located between the radial magnetron and the vacuum chamber. During operation, the plurality of surface-treated structures are treated using plasma generated in a plasma generation region near the radial magnetron. The external power supply also includes field-generating electronic circuitry, which is configured to perform: High-power pulsed plasma magnetron discharge is generated by using a large-current negative direct current (DC) pulse applied to the axial electrode, and After terminating the negative DC pulse, a configurable continuous positive voltage kick pulse is generated and supplied to the axial electrode; and During the generation process, logic circuitry configured by the program processor issues control signals to control at least one kick pulse attribute of the continuous positive voltage kick pulse, the kick pulse attribute being derived from a group consisting of a start delay, duration, amplitude, and frequency including its modulation. The system further includes a secondary internal permanent magnet assembly and a secondary external permanent magnet assembly. The secondary internal permanent magnet assembly is coupled to a magnet substrate to provide magnetic coupling to the main permanent magnet assembly via physical and / or magnetic connections. The secondary internal permanent magnet assembly is further configured to allow motion to be applied from the secondary external permanent magnet assembly, which is placed outside the secondary internal permanent magnet assembly and physically rotated by external actuation to rotate the secondary internal permanent magnet assembly, thereby achieving the desired motion of the main permanent magnet assembly.

17. A roll-to-roll coating system for simultaneously depositing high-quality films from a single radial magnetron on multiple flexible substrate surfaces, the system comprising: Vacuum chamber assembly, including vacuum chamber, gas management system and vacuum pumping system; Radial magnetron, including target material; External power supply; as well as A roll-to-roll winding conveyor system is used to simultaneously transport substrates to the plasma processing zone. In operation, the radial magnetron generates a plasma field for producing the plasma processing zone. The external power supply also includes field-generating electronic circuitry, which is configured to perform: High-power pulsed plasma magnetron discharge is generated by using a large-current negative direct current (DC) pulse applied to the axial electrode, and After terminating the negative DC pulse, a configurable continuous positive voltage kick pulse is generated and supplied to the axial electrode; and During the generation process, logic circuitry configured by the program processor issues control signals to control at least one kick pulse attribute of the continuous positive voltage kick pulse, the kick pulse attribute being derived from a group consisting of a start delay, duration, amplitude, and frequency including its modulation. The system further includes a secondary internal permanent magnet assembly and a secondary external permanent magnet assembly. The secondary internal permanent magnet assembly is coupled to a magnet substrate to provide magnetic coupling to the main permanent magnet assembly via physical and / or magnetic connections. The secondary internal permanent magnet assembly is further configured to allow motion to be applied from the secondary external permanent magnet assembly, which is placed outside the secondary internal permanent magnet assembly and physically rotated by external actuation to rotate the secondary internal permanent magnet assembly, thereby achieving the desired motion of the main permanent magnet assembly.

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