Continuous electromagnetic characterization system for long length high-temperature superconductors at low temperature in high background magnetic fields

Abstract

Techniques for reel-to-reel assessment of a high-temperature superconducting (HTS) tape are provided. The techniques include a cryocooler-powered cryogenic system configured to cool the HTS tape in a background magnetic field. The cryocooler-powered cryogenic system may be free of liquid cryogenic. The cryocooler-powered cryogenic system may include a measurement zone, where the magnetic field is perpendicular to the path of the HTS tape. The techniques may also include a Hall sensor array within the measurement zone. The Hall sensor array may be configured to scan a magnetic field at a surface of the HTS tape to measure a screening-current-induced field and separate it from the background magnetic field. The techniques may also include a data acquisition (DAQ) module operably coupled to the Hall sensor array. The DAQ module may be configured to oversample Hall voltages.

Description

[0001] CONTINUOUS ELECTROMAGNETIC CHARACTERIZATION SYSTEM FOR LONG LENGTH HIGH-TEMPERATURE SUPERCONDUCTORS AT LOW TEMPERATURE IN HIGH BACKGROUND MAGNETIC FIELDS

[0002] CROSS-REFERENCE TO RELATED APPLICATIONS

[0003] The present application claims priority to U.S. Provisional Patent Application 63 / 573,220, filed April 2, 2024, the contents of which are incorporated by reference herein in its entirety.

[0004] STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

[0005] This invention was made with government support under Grant No. DE-AC02-09- CH 11466 awarded by the Department of Energy. The government has certain rights in the invention.

[0006] TECHNICAL FIELD

[0007] The present disclosure is drawn to systems and methods for reel-to-reel testing of high temperature superconducting tapes at very low temperatures (e.g. , below 77K, preferably about 20K) and high magnetic fields (e.g., above 5 T, preferably about 20 T).

[0008] BACKGROUND

[0009] This section is intended to introduce the reader to various aspects of art, which may be related to various aspects of the present disclosure that are described and / or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present disclosure. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art.

[0010] High-temperature superconductors (HTS), including rare-earth barium copper oxide (REBCO) coated conductors, stand as the conductor of choice for ultra-high-field superconducting magnets, next-generation accelerators, and compact fusion reactors. Coated conductors have become the dominant fusion industry choice because REBCO is the most performative of all present superconductors. Performance of coated conductors, however, are highly variable run-to-run, manufacturer to manufacturer. A primary challenge in HTS magnet technology lies in the nascent quench protection system. Notably, low-critical-current (7C) defects in HTS conductors, introduced during manufacturing and coiling processes, may act as localized hot spots, triggering quenches in HTS magnets. Most HTS magnets necessitate defect-free conductors, and even cable-wound magnets, which allow current sharing between REBCO tapes, require full identification of weak spots prior to cabling and winding processes.

[0011] Despite advancements in HTS conductor technology, the elimination of defects during manufacturing remains elusive. It is harder to make longer tapes without Icdefects / dropouts. Tens of thousands of kilometers of HTS conductors are needed for a single commercial magnetic confinement fusion power plant. T ens of hundreds of commercial fusion power plants are needed to bring fusion into the US electrical grid by the mid-century.

[0012] BRIEF SUMMARY

[0013] Various deficiencies in the prior art are addressed below by the disclosed systems and methods for reel-to-reel assessment of a high temperature superconducting (HTS) tape.

[0014] In various aspects, a system for reel-to-reel assessment of a high temperature superconducting (HTS) tape on a path between a first reel and a second reel may be provided. The system may include a cryocooler-powered cryogenic system. The cryocooler-powered cryogenic system may be configured to cool the HTS tape in a background magnetic field. The cryocooler-powered cryogenic system may be free of liquid cryogenic. The cryocooler- powered cryogenic system may define an internal volume of space in which the HTS tape may pass through. The internal volume of space may include a measurement zone. The background magnetic field in the measurement zone may be perpendicular to the path of the HTS tape in the measurement zone. A magnetic field strength of the background magnetic field in the measurement zone may be configured to overwrite a magnetization history of the HTS tape.

[0015] The system may also include a Hall sensor array within the measurement zone. The Hall sensor array may include a plurality of chips. The Hall sensor array may be configured to scan a magnetic field at a surface of the HTS tape to measure a screening-current-induced field (SCF) and separate it from the background magnetic field.

[0016] The system may also include a data acquisition (DAQ) module operably coupled to the Hall sensor array. The DAQ module may be configured to oversample Hall voltages.

[0017] In some embodiments, each chip of the plurality of chips forming the Hall sensor array may have an active area in a plane parallel to the path of the HTS tape in the measurement zone of no more than 20,000 pm2. The Hall sensor array may include at least two rows of chips in a direction perpendicular to the path of the HTS tape and at least two columns of chips in a direction parallel to the path of the HTS tape. In some embodiments, each chip may be separated from an adjacent chip by about 0.25 mm to 0.65 mm. The Hall sensor array may include at least 21 chips.

[0018] In some embodiments, a magnetic field strength in the measurement zone may be at least 8 T. In some embodiments a minimum temperature in the measurement zone may be about 20 K. A first resolution of the Hall sensor array in a direction perpendicular to the path of the HTS tape may be between about 0. 1 mm to 0.65 mm. A second resolution of the Hall sensor array in a direction parallel to the path of the HTS tape may be between about 0. 1 mm to 2 mm.

[0019] In some embodiments, the cryocooler-powered cryogenic system may be a single stage device. In some embodiments, the internal volume of space may be substantially cylindrical. The cryocooler-powered cryogenic system may include thermal and radiation disposed circumferentially around the internal volume of space. In some embodiments, the cryocooler- powered cryogenic system may include a thermal link coupled to a cold head.

[0020] In some embodiments, the system may further include at least one motor. The at least one motor may be configured to control a speed of the HTS tape moving from the first reel to the second reel. The speed may be controlled based on the length of the Hall sensor array in a direction parallel to the path of the HTS tape.

[0021] In some embodiments, the cryocooler-powered cryogenic system may include one or more conduction cooling plates and / or rods.

[0022] In various aspects, a method for reel-to-reel assessment may be provided. The method may include unwinding a high temperature superconducting (HTS) tape from a first reel. The method may also include cooling the HTS tape by exposing the HTS tape to a cryocooler- powered cryogenic system, wherein the HTS tape is exposed to a perpendicular background magnetic field. The method may further include scanning a magnetic flux at a surface of the HTS tape using a Hall sensor array to measure a screening-current-induced field (SCF) and separating it from the perpendicular background magnetic field by exciting the Hall sensor array with a precise and stable direct current source and measuring Hall voltages with a data acquisition (DAQ) module. The DAQ module may be configured to oversample the Hall voltages.

[0023] In some embodiments, the method may further include storing, in a dataset, the Hall voltages and / or SCF. The method may further include visually representing at least a portion of the SCF for at least part of the HTS tape.

[0024] In some embodiments, the method may further include determining, based on the Hall voltages and / or SCF, whether the HTS tape satisfies a predetermined quality metric. In some embodiments, the HTS tape may travel at a speed of at least 100 mm / sec while maintaining a first resolution of the Hall sensor array in a direction perpendicular to the path of the HTS tape of 0.1 mm to 0.65 mm, and a second resolution of the Hall sensor array in a direction parallel to the path of the HTS tape of 0. 1 mm to 2 mm.

[0025] In some embodiments, the magnetic field strength may be between about 8 T to 20 T. The temperature that the HTS tape is exposed to may be between about 20 K to 25K.

[0026] BRIEF DESCRIPTION OF FIGURES

[0027] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the present disclosure and, together with a general description of the present disclosure given above, and the detailed description of the embodiments given below, serve to explain the principles of the present disclosure.

[0028] Figure 1 shows a block diagram of an embodiment of a system for reel-to-reel assessment of a high temperature superconducting (HTS) tape.

[0029] Figures 2A-2C show various embodiments of a Hall sensor array.

[0030] Figure 3 shows an embodiment of a Hall sensor array chip and corresponding dimensions.

[0031] Figure 4 shows an embodiment of an implementation of a Hall sensor array.

[0032] Figure 5 shows an embodiment of a system for reel-to-reel assessment of a high temperature superconducting (HTS) tape.

[0033] Figure 6 shows an embodiment of a system for reel-to-reel assessment of a high temperature superconducting (HTS) tape.

[0034] Figures 7A-7B show an embodiment of an implementation of a Hall sensor array.

[0035] Figure 8 shows a flow diagram of a method.

[0036] Figure 9 depicts a graph of critical current measurement as a function of position of an HTS tape.

[0037] It should be understood that the appended drawings are not necessarily to scale, presenting a somewhat simplified representation of various features illustrative of the basic principles of the present disclosure. The specific design features of the sequence of operation as disclosed herein, including, for example, specific dimensions, orientations, locations, and shapes of various illustrated components, will be determined in part by the particular intended application and use environment. Certain features of the illustrated embodiments have been enlarged or distorted relative to others to facilitate visualization and clear understanding. In particular, thin features may be thickened, for example, for clarity or illustration. DETAILED DESCRIPTION

[0038] The following description and drawings merely illustrate the principles of the present disclosure. It will thus be appreciated that those skilled in the art will be able to devise various arrangements that, although not explicitly described or shown herein, embody the principles of the present disclosure and are included within its scope. Furthermore, all examples recited herein are principally intended expressly to be only for illustrative purposes to aid the reader in understanding the principles of the present disclosure and the concepts contributed by the inventor(s) to furthering the art and are to be construed as being without limitation to such specifically recited examples and conditions. Additionally, the term, "or," as used herein, refers to a nonexclusive or, unless otherwise indicated (e.g., “or else” or “or in the alternative”). Also, the various embodiments described herein are not necessarily mutually exclusive, as some embodiments can be combined with one or more other embodiments to form new embodiments.

[0039] The numerous innovative teachings of the present application will be described with particular reference to the presently preferred exemplary embodiments. However, it should be understood that this class of embodiments provides only a few examples of the many advantageous uses of the innovative teachings herein. In general, statements made in the specification of the present application do not necessarily limit any of the claims. Moreover, some statements may apply to some features but not to others. Those skilled in the art and informed by the teachings herein will realize that the present disclosure is also applicable to various other technical areas or embodiments.

[0040] The advent of high-temperature superconductors (HTS) has revolutionized the field of superconductivity, offering unprecedented opportunities for high-field applications in fusion, high energy physics (HEP) and other basic science research circumstances. These applications demand superconducting tapes that are not only longer but also exhibit uniform high- performance characteristics. However, the development and deployment of HTS technologies face significant challenges, particularly in the continuous characterization of these materials to ensure their performance under extreme working conditions.

[0041] Characterizing the properties of high-temperature superconducting (HTS) tape is crucial for ensuring the reliability and performance of superconducting systems. These tapes are typically used in applications such as power transmission, magnetic resonance imaging (MRI), and particle accelerators, where maintaining the integrity of the superconducting state is essential. One of the most critical properties to characterize is the critical current — the maximum current that the tape can cany without transitioning from its superconducting state to a normal resistive state. Manufacturing defects, such as impurities or inconsistencies in the tape’s composition or structure, can lead to localized variations in critical current, which can, in turn, increase the likelihood of quenching. Quenching refers to the sudden loss of the superconducting state, often triggered by exceeding the critical current or by the presence of defects that cause localized heating. This transition can cause a rapid rise in temperature, potentially leading to catastrophic damage or failure of the system.

[0042] To prevent quenching and ensure the smooth operation of HTS-based technologies, it is essential to detect these defects early in the manufacturing process. This requires advanced quality assurance systems and methods that can accurately measure the critical current across the entire length of the HTS tape. These systems must be capable of identifying regions of the tape that deviate from expected performance and flagging potential weak points before they can lead to operational failures. Effective quality control not only ensures that the HTS tape meets the required specifications for critical current and other properties but also helps maintain the overall integrity of the superconducting system, reducing the risk of failure and extending the lifespan of the device. Therefore, robust characterization and quality assurance methods are indispensable for the development of reliable and efficient HTS technologies.

[0043] Accurate testing for quality assurance of HTS tapes necessitates simulating the extreme conditions these tapes will encounter in real-world applications. Specifically, HTS tapes are expected to maintain their superconducting properties at very low temperatures (~20K) and in high magnetic fields (~20T). The present disclosure introduces techniques designed to test HTS tapes under these challenging conditions, ensuring they perform reliably in their intended environments.

[0044] In various aspects, a system for reel-to-reel assessment of a high temperature superconducting (HTS) tape on a path between a first reel and a second reel may be provided. Referring now to FIG. 1, a block diagram of a system (100) is shown. The system may include a cryocooler-powered cryogenic system (104). The cryocooler-powered cryogenic system (104) may be configured to cool an HTS tape (102). As shown in FIG. 1, the HTS tape may be relayed from a first reel (110) to a second reel (111). For instance, the HTS tape may be unwound from the first reel (110) and moved on a path (50) through the cryocooler-powered cryogenic system (104). The HTS tape may then exit the cryocooler-powered cryogenic system and be re-wound by the second reel. While FIG. 1 shows the HTS tape being relayed through a plurality of reels (110), (111), (112), (113), (114), (115), one skilled in the art and informed by the teachings herein will appreciate that the system may include any suitable number of reels. Also, while the path of the reels is shown going from the — x -» +x region, this path may also be reversed.

[0045] In some embodiments, the cryocooler-powered cryogenic system may operate as a single-stage cryocooler.

[0046] In some embodiments, the cryocooler-powered cryogenic system may include one or more conduction cooling plates and / or rods (170). The one or more conduction cooling plates and / or rods may be either directly or indirectly in contact with the HTS tape as it travels through the cryocooler-powered cryogenic system. For instance, the one or more conduction cooling plates and / or rods may be separated from the HTS tape by a material thermally coupled to the HTS tape. The one or more conduction cooling plates and / or rods may be formed by a high thermal conductivity material (such as copper or aluminum).

[0047] While the conduction cooling plates or rods are shown as a singular unit in FIG. 1, it is envisioned that there may be a plurality of conduction cooling plates and / or rods. For instance, the one or more conduction cooling plates and / or rods (170) may be broken into segments, e.g., a first, second, and third segment. The first segment may be configured to cool the HTS tape to a first temperature Ti. The second segment may be configured to cool the HTS tape to a second temperature 72. The third segment may be configured to cool the HTS tape to a third temperature 7s (77I>72>73). In this embodiment, the cryocooler-powered cryogenic system may operate as a multistage device. In some embodiments, the one or more conduction cooling plates and / or rods may operate in a single segment. In such embodiments, the cryocooler- powered cryogenic system may operate as a single-stage cryocooler.

[0048] The cryocooler-powered cryogenic system eliminates the need for liquid cryogens. Traditional reel-to-reel measurement systems typically rely on liquid cryogens, such as nitrogen or helium, for cooling the HTS tape. However, the use of liquid cryogens presents challenges, including their rapid depletion, which undermines the cost-effectiveness of the system. Additionally, maintaining precise temperature control with liquid cryogens can be difficult. By replacing liquid cryogens with a liquidless cryogenic system, both of these issues are effectively addressed.

[0049] Referring still to FIG. 1, the cryocooler-powered cryogenic system may define an internal volume of space (105). The internal volume of space may include a first zone (107) and a measurement zone (109). In some embodiments, the first zone may be in a region of a background magnetic field in which the background magnetic field is parallel to the path of the HTS tape. In some embodiments, the measurement zone may be in a region of a background magnetic field in which the background magnetic field is perpendicular to the path of the HTS tape. The magnetic field strength in the measurement zone may be at least 8 T. As shown in FIG. 1, the system may include a magnetic field generator (120). The magnetic field generator may be configured to generate and align a background magnetic field in a direction perpendicular to a path of the HTS tape in the measurement region.

[0050] In some embodiments the magnetic field generator may include a solenoid. In some embodiments, the solenoid may enclose the HTS tape, one or more conduction cooling plates and / or rods, and Hall sensor array. The solenoid may be configured to generate a background magnetic field in a direction perpendicular to the HTS tape in the measurement zone (in the y- direction according to the orientation in FIG. 1). In some embodiments, the solenoid may generate a magnetic field strength between about 0.5T and 20T. In some embodiments, the solenoid may generate a magnetic field strength between about 5T and 15T. In some embodiments, the solenoid may generate a magnetic field strength of about 20T. In some embodiments, the solenoid may generate a magnetic field strength of at least 8 T.

[0051] In some embodiments, the magnetic field strength of the background magnetic field may be strong enough to overwrite a magnetization history of the HTS tape.

[0052] Still referring to FIG. 1, the system may include a Hall sensor array (130) within the measurement zone. The Hall sensor array (130) may include a plurality of chips. The Hall sensor array may be configured to scan a magnetic field at the surface of the HTS tape to measure a screening-current-induced field (SCF) and separate it from the background magnetic field.

[0053] The system may also include a data acquisition (DAQ) module (140) operably coupled to the Hall sensor array. The DAQ module may be configured to oversample Hall voltages. In some embodiments, the DAQ module may be operably coupled to the Hall sensor array via a wired connection. In other embodiments, such as the one shown in FIG. 1, the DAQ module may be operably coupled to the Hall sensor array via a wireless connection. In wireless embodiments, the Hall sensor array and DAQ module may include wireless processor(s) and / or modules such as a Bluetooth communication module, wireless infrared (IR) interface, a wireless local area network (WLAN) interface, or a wireless cellular data interface to enable the communication of data between the DAQ module and the Hall sensor array.

[0054] The DAQ module (140) may also be operably coupled to a display interface (160). In this manner, the display interface may be configured to display measurements corresponding to the screening-current- induced field. In some embodiments, the display interface (160), may be configured to display the screening-current-induced field. The display interface may be configured to display a measured magnetic field strength. The display interface may be configured to alert a user if a manufacturing defect of the HTS tape is detected. The display interface may be configured to display critical current. The critical current may be determined by the screening-current induced field.

[0055] In some embodiments, the DAQ module and / or Hall sensor array may be operably coupled to a computer-readable storage means (not shown). The computer-readable storage means may include a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), a static random access memory (SRAM), a portable compact disc read-only memory (CD-ROM), a digital versatile disk (DVD), a memory stick, a floppy disk, and / or a mechanically encoded device, and any suitable combination of the foregoing.

[0056] In some embodiments, the system may further include at least one motor (150). As shown in FIG. 1, the at least one motor (150) may be operably coupled to the first reel. The at least one motor may be configured to control a speed of the HTS tape moving from the first reel to the second reel. In some embodiments, the speed is controlled based on a length of the Hall sensor array in a direction parallel to the path of the HTS tape. The speed of the motor may also be adjusted according to a desired resolution of the Hall sensor array. In some embodiments, the speed of the HTS tape may be between about 50 mm / sec to 150 mm / sec. In some embodiments, the speed of the HTS tape may be between about 75 mm / sec to 125 mm / sec. In some embodiments, the speed of the HTS tape may be about 100 mm / sec.

[0057] As shown in FIG. 1, the system of reels may be configured to move the HTS tape in a direction substantially in the x- and y-direction. FIG. 1 shows the HTS tape being moved substantially in the .v-direction by the first reel (110), before being moved in substantially the y- i recti on by a third reel (112). When the HTS tape (102) is being moved in substantially the y-direction, this path may be parallel to the background magnetic field.

[0058] As seen in FIG. 1 , the background magnetic field may be generated in the y-direction. In this configuration, the HTS tape will not experience any Hall effect voltages while it travels in a region with a background magnetic field parallel to the path of the HTS tape. This is explained by the Lorentz force equation F = q(E + v x B). Because the motion is parallel to the magnetic field, the Lorentz force is zero and thus the Hall effect voltage would also be zero. However, when the HTS tape is moved substantially in the x-direction within the cryocooler- powered cryogenic system, the perpendicular background magnetic field imparts a Lorentz force on the wire and gives rise to a Hall effect voltage.

[0059] In some embodiments, the internal volume of space (105) may be substantially cylindrical. While the cross-section of the system of FIG. 1 shows the internal volume of space being substantially rectangular, those skilled in the art will appreciate that the cross section may correspond to a cylindrical cryocooler-powered cryogenic system, like the one shown in FIGS. 5-6.

[0060] In some embodiments, a bend piece (180) may be included. The bend piece may be configured to adjust a path of the HTS tape in the measurement zone, such that the HTS tape is moved closer to the Hall sensor array for more precise measurement.

[0061] Referring now to FIG. 2A, a cross-sectional view of an embodiment of the Hall sensor array is shown. The Hall sensor array may include a plurality of chips (210) (hereinafter “chips” or singular “chip”). Each chip may form a sensor within the Hall sensor array. The chips may be operably coupled to a surface (205) of the Hall sensor array. In some embodiments, the surface of the Hall sensor array may be a printed circuit board (PCB). As shown in FIG. 2A, the Hall sensor array may include at least 21 chips. Although it is envisioned that the Hall sensor array may include more than 21 chips. For example, the Hall sensor array may include greater than 30 chips. The Hall sensor array may include greater than 35 chips. Although, it is also envisioned that the Hall sensor array may include less than 21 chips. For example, the Hall sensor array may include between 11-20 chips.

[0062] In some embodiments, each Hall sensor chip may be separated a distance D. In some embodiments, D may be between 0.1 mm and 0.9 mm. In some embodiments, D may be between 0.2 mm and 0.8 mm. In some embodiments, D may be between 0.25 mm and 0.65 mm (see FIG. 2B).

[0063] Although the Hall sensor array is shown as being substantially rectangular, those skilled in the art and informed by the present disclosure, will appreciate that the Hall sensor array may be a square, pentagonal, hexagonal, or a substantially circular shape. Similarly, the plurality of chips (210) are shown in FIG. 2A as forming a square shape. Although, the individual chips may be square, one skilled in the art and informed by the present disclosure will appreciate that the chips may be pentagonal, hexagonal, or substantially circular in shape.

[0064] Still referring to FIG. 2A, the Hall sensor array (130) is shown as being arranged in 3 rows, each row having an equal number of chips. While this configuration may be suitable in circumstances where the Hall sensor array forms a square or rectangular shape, it may not be suitable for arrangements where the Hall sensor array forms a pentagonal, hexagonal, or circular shape. In those configurations, the Hall sensor array may include a plurality of rows, each having N chips. In some embodiments, N may be the same for each row. In some embodiments, at least one row of the plurality of rows may have more chips than at least one other row. In some embodiments, at least one row of the plurality of rows may have less chips than at least one other row.

[0065] In some embodiments, the Hall sensor array may include only a singular column. In those embodiments, the Hall sensor array may include a singular column of a plurality of chips. In some embodiments, there may be greater than 21 chips. In some embodiments, there may be less than 21 chips. In some embodiments, the plurality of chips may include 21 chips. In singular column embodiments, the Hall sensor array may be aligned along a width of the HTS tape (i.e., the column of chips scans the entire width of the HTS tape as it passes through the measurement zone).

[0066] Still referring to FIG. 2A, the Hall sensor array (130) may have a width W. The width JV of the Hall sensor array may correspond to a width of the HTS tape. For example, where a width of the HTS tape is about 5 mm, the width of the Hall sensor array may also be about 5 mm.

[0067] Referring now to FIG. 2B, a cross-sectional view of a row of an embodiment of a singular row of a Hall sensor array is shown. Each chip may have a width w and may be separated by a diameter D. In some embodiments. D may be between about 0.25 mm and 0.65 mm. In this configuration, at least one chip has a size and shape different from at least one other chip. Similarly, according to some embodiments, the diameter between chips may be different for at least two chips.

[0068] Referring now to FIG. 2C. another embodiment of the Hall sensor array is shown. In this embodiment, the rows within the Hall sensor array are each offset by a distance d. In some embodiments, d may be greater than 0. 1 mm. In some embodiments, d may be greater than 0.2 mm. In some embodiments, d may be greater than 0.3 mm. In some embodiments, d may be greater than 0.4 mm. In some embodiments, d may be greater than 0.5 mm.

[0069] In some embodiments, each chip of the plurality of chips forming the Hall sensor array may have an active area in a plane parallel to the path of the HTS tape in the measurement zone of no more than 20,000 pm2. For instance, briefly referring to FIG. 4, the Hall sensor array may be aligned above the HTS tape in a plane (460) parallel to the HTS tape. In this circumstance, each chip may have an active area of no more than 20.000 pm2. As will be understood by those skilled in the art, the Hall sensor array may be aligned horizontally in a plane parallel with the HTS tape as in FIG. 6.

[0070] According to the various embodiments of the Hall sensor array configuration, the length of the Hall sensor array, the width of the chips, the offset between Hall sensor array rows, the row configuration, the Hall sensor array shape, and the diameter between chips may be adjusted, either individually, or in combination with one another to achieve a desired resolution. In some embodiments, a first resolution of the Hall sensor array in a direction perpendicular to the path of the HTS tape may be between about 0.1 mm to 0.65 mm. A first resolution off the Hall sensor array in a direction perpendicular to the path of the HTS tape may be between about 0.2 mm to 0.5 mm. A first resolution off the Hall sensor array in a direction perpendicular to the path of the HTS tape may be between about 0.3 mm to 0.4 mm.

[0071] A second resolution of the Hall sensor array in a direction parallel to the path of the HTS tape may be between about 0.1 mm to 2 mm. A second resolution off the Hall sensor array in a direction perpendicular to the path of the HTS tape may be between about 0. 12 mm to 0. 18 mm. A second resolution off the Hall sensor array in a direction perpendicular to the path of the HTS tape may be between about 0. 14 mm to 0. 16 mm.

[0072] As shown in FIGS. 2A and 2C, the Hall sensor array may include at least two rows of chips and at least two columns of chips. Although it will be appreciated that there may be more or less than two rows. Likewise, there may be more or less than two columns.

[0073] Referring now to FIG. 3, an embodiment of aHall sensor array chip (215) (alternatively referred to as “chip”) is shown. The chip may have a depth (330) of about 0.3 mm. In some embodiments, the chip may be separated from at least one other chip by a distance (320) between about 0.25 mm to 0.65 mm. In some embodiments, a length (310) may be between about 0.08 mm to 0. 15 mm.

[0074] The present disclosure uses a Hall Sensor array for higher spatial resolutions of critical current imaging compared to other technologies such as Scanning Hall Probe Microscopy (SHPM) and TapeStar (low resolution). Table I shows a comparison of various techniques for REBCO coated conductor performance inspection.

[0075] Table I

[0076] Referring now to FIG. 4, an embodiment of the Hall sensor array implementation is shown. The Hall sensor array may be operably coupled to a supporting surface (405), which, in this embodiment, is an L-shaped structure having an upper panel (415) and a lower panel (410). The Hall sensor array may be coupled to a horizontal extension (430) from the upper panel (415), while the lower panel may include bumpers (420) configured to create an entry point (442) and an exit point (444) for the HTS tape. In some embodiments, the HTS tape may configured to pass through the entry point and exit point, respectively. The Hall sensor arraymay be further configured to scan the HTS tape as it moves from the entry point to the exit point, allowing for continuous monitoring of the tape during its passage.

[0077] In the configuration depicted in FIG. 4, the Hall sensor array is shown scanning a top portion of the HTS tape. However, it is envisioned that FIG. 4 could be rearranged such that the Hall sensor array is positioned beneath the HTS tape and may measure a bottom portion of the HTS tape.

[0078] Additionally, while the horizontal extension is shown as substantially rectangular, it is envisioned that the horizontal extension may be pentagonal, hexagonal, heptagonal, circular, or any other shape necessary to support integration with the Hall sensor array.

[0079] The Hall sensor array may be disposed a distance L from the HTS tape as it enters the measurement zone. In some embodiments, the distance L may be between about 0.01 mm to 1 mm. In some embodiments the distance L may' be between about 0.05 mm and 0.75 mm. In some embodiments, the distance L may be less than about 0.2 mm.

[0080] Referring now to FIG. 5, another embodiment of the system for reel-to-reel assessment of a high temperature superconducting (HTS) tape is shown. As shown in FIG. 5, the internal volume of space is cylindrical. Although, as previously mentioned, the internal volume of space may be any suitable shape. Here, the cryocooler-powered cryogenic system includes outer and inner concentric cylinders. The outer concentric cylinder may form the magnetic field generator (120). The magnetic field generator may be configured to generate a background magnetic field. In some embodiments, the magnetic field generator may be a solenoid. The inner concentric cylinder may include one or more conduction cooling plates and / or rods (170).

[0081] The system may also include a cold head (520). The cold head may be from a standard industrial cryocooler. For example, the cold head may be from a 20K single stage commercial cryocooler such as Cryomech AL630 series (with 100 W cooling capacity at 20K). Alternatively, the cryocooler may be a dual stage cryocooler such as Cryomech pulsed tube series (PT425 or PT435 series of a cooling capacity ~ 3W at 4.2K and 55W at 45K). The cold head may be thermally coupled to the one or more conduction cooling plates and / or rods. The cold head may be configured to lower the temperature of the one or more conduction cooling plates and / or rods. The cold head (520) may be operably coupled to a base member (530). Although FIG. 5 only shows a single cold head, embodiments with multiple cold heads are also envisioned.

[0082] In some embodiments, a thermal link may be provided between the cold head (520) and the HTS tape (102). The thermal link (525) may be operably coupled to the HTS tape by one or more thermal straps (523). In some embodiments, the thermal link may be in direct contact with the HTS tape. In some embodiments, the thermal link may be in indirect contact with the HTS tape. For example, a thermal shield may provide an indirect contact point between the HTS tape and the thermal link. The thermal straps and / or thermal link may be formed by aluminum and / or copper, although those skilled in the art will appreciate that any suitable metal may be used such that the metal may achieve temperatures lower than 20 K. preferably lower than 4 K.

[0083] In some embodiments, the ciyocooler-powered cryogenic system may include thermal and radiation disposed circumferentially around the internal volume of space.

[0084] Referring now to FIG. 6, another embodiment of a system for reel-to-reel assessment of a high temperature superconducting (HTS) tape is shown. Similar to FIG. 5, one or more concentric cylinders are included. The outer concentric cylinder may form the magnetic field generator (120).

[0085] According to FIG. 6, one or more primary vertical support structures (622) may be operably coupled to a top horizontal support structure (632). The top horizontal structure may be operably coupled to a bottom horizontal support structure (634) by one or more secondary vertical support structures (624). AHall sensor array (130) may be operably coupled to the one or more secondary vertical support structures.

[0086] Still referring to FIG. 6, the cryocooler-powered cryogenic system may include a first cavity (642) and second cavity (644). One or more reels may direct an HTS tape through the first and second cavity. The HTS tape may be fed through the first cavity and vertically directed to a reel configured to redirect a path of the HTS tape. The HTS tape may be redirected at an angle of about 90°. Once redirected, the HTS tape may enter a measurement zone. The measurement zone may include a background magnetic field. The background magnetic field may be perpendicular to the path of the HTS tape.

[0087] Still referring to FIG. 6, the cryocooler-powered cryogenic system may include a cold head (520). The cold head may be operably coupled to a first conduction cooling plate (652) by one or more conduction current leads (656). The first conduction cooling plate may be cooled by the cold head to a first temperature Ti. The first conduction cooling plate may be operably coupled to a second conduction cooling plate (654). The second conduction cooling plate (654) may be cooled by the cold head and / or the first conduction cooling plate to a second temperature T . In some embodiments, 72<7i.

[0088] In some embodiments, the first and / or second conduction cooling plate may be operably coupled to the HTS tape. The first and second conduction cooling plate may be configured to cool the HTS tape.

[0089] Referring now to FIG. 7A, another embodiment of an implementation of the Hall sensor array is shown. In this embodiment, the Hall sensor array may be disposed horizontally and parallel to the HTS tape as it passes through the measurement zone.

[0090] Referring now to FIG. 7B, an alternative view of FIG. 7A is shown. The Hall sensor array may be disposed a distance r from the HTS tape as it enters the measurement zone. In some embodiments, the distance r may be between about 0.01 mm to 1 mm. In some embodiments the distance r may be between about 0.05 mm and 0.75 mm. In some embodiments, the distance r may be less than about 0.2 mm.

[0091] In some embodiments, a width of the HTS tape may be betw een about 1 to 30 mm. The width of the HTS tape may be between about 5 to 25 mm. The width of the HTS tape may be between about 10 to 20 mm. The width of the HTS tape may be about 13 mm. The width of the HTS tape may be about 16 mm.

[0092] In some embodiments, a minimum temperature in the measurement zone may be about 25 K. In some embodiments, a minimum temperature in the measurement zone may be about 20 K. A minimum temperature in the measurement zone may be less than 19 K. A minimum temperature in the measurement zone may be less than 15 K. A minimum temperature in the measurement zone may be less than 10 K. A minimum temperature in the measurement zone may be less than 5 K. In various aspects, a method (800) for reel-to-reel assessment may be provided. Referring now to FIG. 8, the method may include unwinding (810) a high temperature superconducting (HTS) tape from a first reel. The method may also include cooling (820) the HTS tape by exposing the HTS tape to a cryocool er-powered cryogenic system. The HTS tape may be exposed to a perpendicular background magnetic field. The method may also include scanning (830) a magnetic flux at a surface of the HTS tape using a Hall sensor array to measure a screening-current-induced field (SCF) and separate it from the background magnetic field by exciting the Hall sensor array with a precise and stable direct current source and measuring Hall voltages with a data acquisition (DAQ) module. The DAQ module may be configured to oversample the Hall voltages.

[0093] In some embodiments, the method may further include storing, in a dataset, the Hall voltages and / or SCF. For example, the DAQ module and / or Hall sensor array may be operably coupled to a computer-readable storage means. The computer-readable storage means may include a portable computer diskette, a hard disk, a random access memory (RAM), a readonly memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), a static random access memory (SRAM), a portable compact disc read-only memory (CD-ROM), a digital versatile disk (DVD), a memory stick, a floppy disk, and / or a mechanically encoded device, and any suitable combination of the foregoing.

[0094] The method may further include visually representing at least a portion of the SCF for at least part of the HTS tape. For example, the critical currents may be determined according to the Hall voltages and / or SCF. The determined critical currents may be utilized by visually mapping the critical current across the HTS tape. The mapping may present a clear representation of the tape's performance and can highlight areas that contain manufacturing defects. Such visualizations can aid manufacturers in identifying and addressing quality issues, optimizing production processes, and improving the overall rel iabi lity and efficiency of the HTS tape in practical applications.

[0095] In some embodiments, the method may further include determining, based on the Hall voltages and / or SCF, whether the HTS tape satisfies a predetermined quality metric. The predetermined quality metric may require less than 10 defects per 100 mm. The predetermined quality metric may require less than 8 defects per 100 mm. The predetermined quality metric may require less than 6 defects per 100 mm. The predetermined quality metric may require less than 4 defects per 100 mm. The predetermined quality metric may require less than 2 defects per 100 mm. The predetermined quality metric may require no defects. In some embodiments, the HTS tape may travel at a speed of at least 100 mm / sec while maintaining a first resolution of the Hall sensor array in a direction perpendicular to the path of the HTS tape of 0.1 mm to 0.65 mm, and a second resolution of the Hall sensor array in a direction parallel to the path of the HTS tape of 0. 1 mm to 2 mm. A first resolution off the Hall sensor array in a direction perpendicular to the path of the HTS tape may be between about 0.2 mm to 0.5 mm. A first resolution off the Hall sensor array in a direction perpendicular to the path of the HTS tape may be between about 0.3 mm to 0.4 mm.

[0096] A second resolution of the Hall sensor array in a direction parallel to the path of the HTS tape may be between about 0.1 mm to 2 mm. A second resolution off the Hall sensor array in a direction perpendicular to the path of the HTS tape may be between about 0. 12 mm to 0. 18 mm. A second resolution off the Hall sensor array in a direction perpendicular to the path of the HTS tape may be between about 0. 14 mm to 0. 16 mm.

[0097] In some embodiments, the speed of the HTS tape may be between about 25 mm / sec to 200 mm / sec. In some embodiments, the speed of the HTS tape may be between about 50 mm / sec to 175 mm / sec. In some embodiments, the speed of the HTS tape may be between about 75 mm / sec to 150 mm / sec. In some embodiments, the speed of the HTS tape may be between about 100 mm / sec to 125 mm / sec. The speed of the HTS tape may be greater than 200 mm / sec. For example, the speed of the HTS tape may be about 210 mm / sec. The speed of the HTS tape may be about 220 mm / sec.

[0098] In some embodiments, the magnetic field strength may be about 8T to 20T. The temperature that the HTS tape may be exposed to may be between about 1 OK to 30K. In some embodiments, the temperature that the HTS tape may be exposed to may be between about 20K to 25K. Additionally, the temperature may be at least 15K. The temperature may be at least 16K. In some embodiments, the temperature may be at least 17 K. In some embodiments, the temperature may be at least 18 K. The temperature may be at least 19 K. The temperature may be at least 20 K. The temperature may be at least 21 K. The temperature may be at least 22 K. The temperature may be at least 23 K. The temperature may be at least 24 K. The temperature may be at least 25 K. The temperature may be at least 26 K.

[0099] Ensuring that HTS tape is free from defects is crucial for its reliable performance. Users of high-temperature superconductors may require that their HTS tapes be defect-free to guarantee optimal functionality. Therefore, in some embodiments, the method may include providing a comprehensive mapping of any defects present in the high-temperature superconductor. This mapping can help identify potential weak points, allowing for early intervention and ensuring the integrity and performance of the HTS tape in its intended application.

[0100] Referring to FIG. 9, an exemplary graph showing the measurement of critical current for a section of HTS tape is presented. This graph illustrates the consistent measurement of critical current as the HTS tape is fed through the system described herein. Ideally, the critical current would remain nearly constant along the entire length of the HTS tape. However, as shown in FIG. 9, sharp drops indicate defects in the tape. In areas where the critical cunent significantly decreases compared to the rest of the tape, the tape behaves like a regular conductor. In these regions, the risk of burnout is significantly increased.

[0101] Various modifications may be made to the systems, methods, apparatus, mechanisms, techniques, and portions thereof described herein with respect to the various figures, such modifications being contemplated as being within the scope of the present disclosure. For example, while a specific order of steps or arrangement of functional elements is presented in the various embodiments described herein, various other orders / arrangements of steps or functional elements may be utilized within the context of the various embodiments. Further, while modifications to embodiments may be discussed individually, various embodiments may use multiple modifications contemporaneously or in sequence, compound modifications and the like.

[0102] Although various embodiments which incorporate the teachings of the present disclosure have been shown and described in detail herein, those skilled in the art can readily devise many other varied embodiments that still incorporate these teachings. Thus, while the foregoing is directed to various embodiments of the present disclosure, other and further embodiments of the present disclosure may be devised without departing from the basic scope thereof. As such, the appropriate scope of the present disclosure is to be determined according to the claims.

Claims

What is claimed is:

1. A system (100) for reel-to-reel assessment of a high temperature superconducting (HTS) tape (102) on a path (50) between a first reel (110) and a second reel (111), comprising: a cryocooler-powered cryogenic system (104) configured to cool the HTS tape in a background magnetic field, the cryocooler-powered cryogenic system being free of liquid cryogenic, where the cryocooler-powered cryogenic system defines an internal volume of space (105) in which the HTS tape may pass through, the internal volume of space including a measurement zone (109), where the background magnetic field in the measurement zone is perpendicular to the path of the HTS tape in the measurement zone, where a magnetic field strength of the background magnetic field in the measurement zone is configured to overwrite a magnetization history of the HTS tape; a Hall sensor array (130) within the measurement zone, the Hall sensor array comprising a plurality of chips (210), the Hall sensor array configured to scan a magnetic field at a surface of the HTS tape to measure a screening-current-induced field (SCF) and separate it from the background magnetic field; and a data acquisition (DAQ) module (140) operably coupled to the Hall sensor array, the DAQ module configured to oversample Hall voltages.

2. The system of claim 1, wherein each chip of the plurality of chips forming the Hall sensor array has an active area in a plane parallel to the path of the HTS tape in the measurement zone of no more than 20,000 pm2.

3. The system of claims 1 or 2, wherein the Hall sensor array comprises at least two rows of chips in a direction perpendicular to the path of the HTS tape and at least two columns of chips in a direction parallel to the path of the HTS tape.

4. The system of any one of claims 1-3, wherein each chip of the plurality of chips is separated from an adjacent chip by about 0.25 mm to 0.65 mm.

5. The system of any one of claims 1-4, wherein the Hall sensor array comprises at least 21 chips.

6. The system of any one of claims 1-5, wherein a magnetic field strength in the measurement zone is at least 8 T.

7. The system of any one of claims 1-6, wherein a minimum temperature in the measurement zone is about 20 K.

8. The system of any one of claims 1-7, wherein a first resolution of the Hall sensor array in a direction perpendicular to the path of the HTS tape is 0. 1 mm to 0.65 mm, and a second resolution of the Hall sensor array in a direction parallel to the path of the HTS tape is 0. 1 mm to 2 mm.

9. The system of any one of claims 1-8, wherein the cryocooler-powered cryogenic system is a single-stage cryocooler.

10. The system of any one of claims 1-9, wherein the internal volume of space is substantially cylindrical.

11. The system of any one of claims 1-10, wherein the cryocooler-powcred cry ogenic system includes thermal and radiation disposed circumferentially around the internal volume of space.

12. The system of any one of claims 1-11, wherein the cryocooler-powered cry ogenic system includes a thermal link (525) coupled to a cold head (520).

13. The system of any one of claims 1-12, further comprising at least one motor (150) configured to control a speed of the HTS tape moving from the first reel to the second reel, where the speed is controlled based on a length of the Hall sensor array in a direction parallel to the path of the HTS tape.

14. The system of any one of claims 1-13, wherein the cryocooler-powered cryogenic system comprises one or more conduction cooling plates and / or rods (170).

15. A method (800) for reel-to-reel assessment, comprising: unwinding (810) a high temperature superconducting (HTS) tape from a first reel;cooling (820) the HTS tape by exposing the HTS tape to a cryocooler-powered cryogenic system, wherein the HTS tape is exposed to a perpendicular background magnetic field; and scanning (830) a magnetic flux at a surface of the HTS tape using a Hall sensor array to measure a screening-current-induced field (SCF) and separating it from the perpendicular background magnetic field by exciting the Hall sensor array with a precise and stable direct current source and measuring Hall voltages with a data acquisition (DAQ) module, where the DAQ module is configured to oversample the Hall voltages.

16. The method of claim 15, further comprising storing, in a dataset, the Hall voltages and / or SCF.

17. The method of claims 15 or 16, further comprising visually representing at least a portion the SCF for at least part of the HTS tape.

18. The method of any one of claims 15-17. further comprising determining, based on the Hall voltages and / or SCF, whether the HTS tape satisfies a predetermined quality metric.

19. The method of any one of claims 15-18, wherein the HTS tape travels at a speed of at least 100 mm / sec while maintaining a first resolution of the Hall sensor array in a direction perpendicular to a path of the HTS tape of 0. 1 mm to 0.65 mm, and a second resolution of the Hall sensor array in a direction parallel to the path of the HTS tape of 0. 1 mm to 2 mm.

20. The method of any one of claims 15-19, wherein a magnetic field strength of the perpendicular background magnetic field is between 8T to 20T.

21. The method of any one of claims 15-20, wherein a temperature that the HTS tape is exposed to is 20K to 25K.

Images