Kit and apparatus for generating a predetermined magnetic field distribution

Abstract

The invention refers to a kit for generating a predetermined magnetic field distribution in a predetermined volume in relation to a device, comprising: a plurality of sensor-source units configured to be placed around the device, wherein each sensor-source unit includes a magnetic field generating element for generating a respective magnetic field in the volume, the respective magnetic field being configured to contribute to the predetermined magnetic field distribution generated by the kit, a magnetic field sensing element for sensing the magnetic field at a surface of the volume, and a bracket to which the magnetic field generating element and the magnetic field sensing element are fixedly attached.

Description

[0001] Kit and apparatus for generating a predetermined magnetic field distribution Field of the Invention

[0002] The present invention relates to a kit for generating a predetermined magnetic field distribution in a predetermined volume in relation to a device. The kit comprises a plurality of sensor-source units configured to be placed around the device.

[0003] The invention further refers to an apparatus for generating a predetermined magnetic field distribution in a predetermined volume in relation to a device, comprising the kit.

[0004] The invention also relates to a use of the kit or the apparatus for a satellite and / or an instrument containing a magnetic field sensor.

[0005] Finally, the invention refers to methods for generating a predetermined magnetic field distribution in a predetermined volume in relation to a device. The methods comprise the step of arranging plurality of sensor-source units around the device.

[0006] Background

[0007] Magnetoencephalography (MEG) is a well-established medical technique for mapping brain electrical activity by recording magnetic fields that this activity generates. The magnetic fields generated by a brain are very weak and an environment in which there is effectively no (or negligible) ambient magnetic field environment is necessary to make them detectable. The magnetic field detecting sensors used in MEG are often based on superconducting quantum interference devices (SQUID). These devices require liquid helium cooling what is very costly. An alternative sensor technology is optically pumped magnetometers (OPM) that do not need cooling thereby reducing cost of the MEG apparatus.

[0008] An environment in which there is effectively no (or negligible) ambient magnetic field (e.g., for MEG applications) is usually delivered using large and very costly magnetically shielded rooms (MSR). These rooms typically comprise walls, floors and ceilings formed from a magnetically shielding material.

[0009] Additionally, MSRs may be equipped with additional systems to cancel any remaining magnetic fields present within the MRS which may arise from limitations of the MSR or from equipment within it. The cost of MSRs is so significant that few institutions can effort MEG devices.

[0010] For MEG measurements, the patient must come to an MSR because the MEG device cannot be moved together with MSR to the patient. Inside the MSR, preferably only non-magnetic objects should be used to reduce additional ambient magnetic fields within the MSR. In addition, and MSR has very limited space and no windows. That limits possibility of bringing tools that can be used to interact with the patient, which is important for checking brain response. The static nature of the MSR prevents one from investigating patients in different environments, for example outside a building or in different environment bringing with it psychical comfort. This is particularly significant if an MSR environment is not comfortable for patients with claustrophobia or is scary for children. Mewburn Ref: 008669863

[0011] 2

[0012] Long-time patient monitoring, for example during sleep is very difficult within an MSR. In addition, an MSR prevents one from combining MEG measurements with other concurrent measurements requiring large devices for other techniques. For example, if one can remove the need for an MSR, this permits a concurrent measurement of MEG and low field MRL In addition, within an MSR one cannot avoid certain time varying magnetic field sources such as a patient’s beating heart or power lines supplying power to MEG equipment within the MSR (e.g., a computer or the like). Where MSR itself needs additional compensation of such remaining internal magnetic fields, that may be delivered using Helmholtz coils or bi-planar coils placed inside the MSR.

[0013] WO 2023 / 079081 A1 refers to improvements in and relating to magnetic field nulling.

[0014] The present invention has been devised in light of the above considerations. The present invention has been devised in light of the above considerations.

[0015] Summary of the Invention

[0016] In a first aspect, a kit for generating a predetermined magnetic field distribution or a predetermined magnetic field in a predetermined volume in relation to a device. The kit comprises a plurality of sensorsource units configured to be placed around the device. Each sensor-source unit includes a magnetic field generating element, a magnetic field sensing, and a bracket. The magnetic field generating element is provided for generating a respective magnetic field in the volume. The respective magnetic field is configured to contribute to the predetermined magnetic field distribution generated by the kit. The magnetic field sensing element is provided for sensing the magnetic field at a surface of the volume. The magnetic field generating element and the magnetic field sensing element are fixedly attached to the bracket.

[0017] In a second aspect, an apparatus for generating a predetermined magnetic field distribution or a predetermined magnetic field in a predetermined volume in relation to a device is provided. The apparatus comprises the kit as described herein and a feedback control unit for controlling the respective magnetic fields generated by each of the plurality of magnetic field generating elements in response to the magnetic field sensed by the plurality of magnetic field sensing elements by controlling the magnetic field generating elements such that the magnetic field values detected by respective magnetic field sensing elements are within a value range corresponding the predetermined magnetic field distribution. In a third aspect, there is provided a use of the kit as described herein and / or the apparatus as described herein for a satellite and / or an instrument containing a magnetic field sensor.

[0018] In a fourth aspect, a method for generating a predetermined magnetic field distribution or a predetermined magnetic field in a predetermined volume in relation to a device is provided. The method comprises the steps of (i) arranging plurality of sensor-source units around the device, (ii) setting a distance between the between a magnetic field generating element and a magnetic field sensing element using an adjustable bracket for each sensor-source unit, (iii) measuring a current magnetic field using the magnetic field sensing elements, and (iv) controlling the magnetic field generating elements based on the measured Mewburn Ref: 008669863

[0019] 3

[0020] current magnetic field such that the magnetic field detected by respective magnetic field sensing elements is within a range corresponding the predetermined magnetic field distribution. Each sensorsource unit includes the magnetic field generating element for generating a respective magnetic field extending into the volume, the respective magnetic fields contributing to the predetermined magnetic field distribution generated by the kit, the magnetic field sensing element for sensing a magnetic field at a surface of the volume, and the adjustable bracket to which the magnetic field generating element and the magnetic field sensing element are fixedly attached.

[0021] In a fifth aspect, a method for generating a predetermined magnetic field distribution or a predetermined magnetic field in a predetermined volume in relation to a device using sensor-source units is provided. Each sensor-source unit includes a magnetic field generating element for generating a respective magnetic field extending into the device, the respective magnetic fields contributing to the predetermined magnetic field distribution generated by the kit, a magnetic field sensing element for sensing a magnetic field at a surface of the volume, and a bracket to which the magnetic field generating element and the magnetic field sensing element are fixedly attached. The method comprises the steps of (i) calculating a distance between the magnetic field generating element and the magnetic field sensing element for each sensor-source unit at their respective locations, (ii) arranging the plurality of sensor-source units at their respective locations, wherein each sensor-source unit has a distance between the between the magnetic field generating element and the magnetic field sensing element based on the calculated distance, (iii) measuring a current magnetic field using the magnetic field sensing elements, and (iv) controlling the magnetic field generating elements based on the measured current magnetic field such that the magnetic field detected by respective magnetic field sensing elements is within a range of variation from the predetermined magnetic field distribution.

[0022] The kit, the apparatus, and the methods described herein provide the advantage that a predetermined magnetic field distribution or a predetermined magnetic field can be generated in a volume of any shape. For example, the shape of the volume is defined by the shape of the device or based on the shape of the device. Thus, the kit, the apparatus, and the methods described herein can be applied to devices of various shapes and / or sizes while providing a predetermined magnetic field distribution in the volume. This allows to apply to the solution described herein to a plurality of devices of various shapes and / or sizes. At the same time, the predetermined magnetic field distribution can be generated using the same algorithms and / or sensor-source units. This may reduce costs and / or for generating the predetermined magnetic field distribution because the same setup and / or approach for generating the magnetic field can be used irrespective of the shape and / or size of the device / volume.

[0023] The device may include any instrument, apparatus, and / or unit that may be shielded from external magnetic fields. Further, the device may include any instrument, apparatus, and / or unit that generates a magnetic field, whereby the surrounding of the device should be shielded from the magnetic field generated by the device. The device may have any size and / or shape.

[0024] The device may be an electron microscopes, an X-ray photoelectron spectroscopy (XPS) system, a satellite and / or an instrument that measures magnetic fields. In this case, the kit and / or the apparatus Mewburn Ref: 008669863

[0025] 4

[0026] may be provided for shielding the device from external magnetic fields which would disturb and / or prevent the device from measuring magnetic fields. In other words, the device may be an instrument for measuring small magnetic fields which may be impossible in the presence of an external magnetic field. For example, the device is an instrument for Magnetoencephalography (MEG).

[0027] The term “external magnetic field” may refer to any magnetic field that is not generated by the kit and / or the apparatus. As explained above, this may include a magnetic field generated by the device or magnetic field that penetrates the device (e.g. the magnetic field of the earth or generated by instrument in the proximity of the device).

[0028] In some examples, the term “predetermined magnetic field distribution” may be considered a distribution of a predetermined magnetic field in the predetermined volume. Further, the term “predetermined magnetic field distribution” may refer to the superposition or addition of the external magnetic field and the magnetic fields that are generated by all magnetic field generating elements. The kit, the apparatus, and the methods described herein may vary or modify the magnetic field generated by the kit (e.g. generated all by magnetic field generating elements) such that the superposition of the external magnetic field with the generated magnetic field corresponds to the predetermined magnetic field or the predetermined magnetic field distribution. Thus, if the external magnetic field is temporally constant, the generated magnetic field is also temporally constant. If the external magnetic field changes of the time, the generated magnetic field changes accordingly over time.

[0029] The predetermined volume in which the predetermined magnetic field distribution or the predetermined magnetic field is generated may correspond to the volume of the device. In other words, an outer surface of the device may correspond to the surface of the volume. In this example, the predetermined magnetic field distribution or the predetermined magnetic field is generated inside the predetermined volume and / or the device. In this case, the predetermined magnetic field distribution or the predetermined magnetic field may be used for generating a bespoke magnetic field inside the device and / or shielding the device from external magnetic fields which may correspond to nulling the external magnetic field.

[0030] Alternatively, the predetermined volume may surround the device. In other words, the predetermined magnetic field distribution or the predetermined magnetic field is generated outside a volume of the device. In this case, the predetermined magnetic field distribution or the predetermined magnetic field may be used for generating a bespoke magnetic field outside device and / or shielding the surroundings of the device from the magnetic field generated by the device which may correspond to nulling the magnetic field generated by the device.

[0031] As described above, the device and / or the volume may have a non-spherical or non-cuboid shape. With prior art solutions, the magnetic field generating element and the magnetic field sensing element may be attached to a scaffold that surrounds the device. The shape of the scaffold is adapted to the shape of the device. Thus, when using the scaffold for a different device having a different shape, the magnetic field generating elements and the magnetic field sensing element may not be arranged at an ideal position. This can be circumvented by the solution described herein in which a kit of sensor-source units is used which can be attached to the device and / or placed around the device. Thus, the respective magnetic field Mewburn Ref: 008669863

[0032] 5

[0033] generating elements and magnetic field sensing elements follow the shape of the device. Further, no scaffold is required that is uniquely made for the respective device. Rather, the plurality of sensor-source units can be produced in high quantities for generating the predetermined magnetic field distribution or the predetermined magnetic field. As the sensor-source units can be identical or similar to each other, the cost for producing the kit may be significantly lower compared to preparing a bespoke scaffold.

[0034] In some examples, the sensor-source units may be identical to each other. Further, the number of sensor-source units of a particular kit can vary. For example, 5, 10, 15, 20, 25, 30, 50, or 100 sensorsource units are provided for respective kit. The number of sensor-source units may depend on the size and / or the size of the volume and / or the device. For example, a larger device may require more sensorsource units compared to a device of smaller size.

[0035] The sensor-source units may be placed around a surface of the device. For example, the source units, optionally the bracket, may be attached to the outer surface of the device. If the volume corresponds to the volume of the device, arranging the sensor-source units at an outer surface of the device simultaneously arranges the sensor-source units at a surface of the volume. Alternatively, if the volume corresponds to surrounding of the device, arranging the sensor-source units at an outer surface of the device simultaneously arranges the sensor-source units at a surface of the volume.

[0036] The sensor-source units may be equally distributed around the device and / or the volume. For example, a distance between any two of the sensor-source unit may be equal. However, it is possible that the distance between respective sensor-source units may vary. For example, the distance may be reduced at the edges and / or corners of the outer surface of the device and / or volume. This may be done because at edges and / or corners the magnetic field may vary more compared to a flat surface. Thus, increasing the number and / or intensity of the sensor-source unit at corners and / or edges may help to generate the predetermined magnetic field at the respective locations which may be considered to correspond to the predetermined magnetic field distribution.

[0037] In an optional embodiment, the magnetic field generating element comprises one or more electrically conductive coils for generating the magnetic field.

[0038] Each magnetic field generating element may be electrically connected (for example using wires and / or a cable) to the feedback control unit. The feedback control unit may control the supply of electrical current to the magnetic field generating element for setting an intensity and / or amplitude of the magnetic field. By controlling each magnetic field generating element, a plurality of magnetic fields is generated by the kit. The sum of the individual magnetic fields may correspond to the predetermined magnetic field distribution or the predetermined magnetic field.

[0039] If two or more coils are provided with the magnetic field generating element, axes of the coils may be parallel to, colinear, or inclined to each other. The orientations of the coils can be set with regard to the magnetic field that is intended to be generated with the sensor-source unit. For example, the magnetic field generating element includes three coils whose axes are each perpendicular to each other. Thus, the magnetic field to be generated can be controlled in three dimensions. Mewburn Ref: 008669863

[0040] 6

[0041] In some examples, the magnetic field sensing element may include one or more sensors configured to measure a strength and / or orientation of the magnetic field. Each magnetic field sensing element may be electrically connected (for example using wires and / or a cable) to the feedback control unit. The feedback control unit may therefore be configured to measure the magnetic field at the surface of the volume, optionally at the outer surface of the device.

[0042] The magnetic field sensing element may be configured to measure the strength of the magnetic field in three dimensions. For example, the magnetic field sensing element is configured to measure the magnetic field strength in three orthogonal directions. In some examples, the magnetic field sensing element includes three sensors. Each sensor is arranged to measure the magnetic field strength in a single dimension. To this end, the magnetic field sensing element may include one or more magnetoresistive sensors. The capability of measuring the magnetic field strength in three dimensions may be helpful for the orthogonal projection method described further below.

[0043] The measured magnetic field may be used for generating the predetermined magnetic field distribution or the predetermined magnetic field. For example, the predetermined magnetic field distribution or the predetermined magnetic field may be the sum of the measured magnetic field and the magnetic field generated by plurality of the magnetic field generating elements. If the predetermined magnetic field distribution or the predetermined magnetic field may correspond to nulling an external magnetic field (e.g. the predetermined magnetic field is a zero magnetic field), the magnetic field to be generated by the plurality of the magnetic field sensing elements is set to cancel the external magnetic field measured by the magnetic field sensing elements. In more general, the magnetic fields generated by the plurality of the magnetic field generating elements may be set such that the superposition of the generated magnetic fields with the external magnetic field (or the magnetic field generated by the device) corresponds to the predetermined magnetic field distribution or the predetermined magnetic field.

[0044] An exemplary algorithm for generating the predetermined magnetic field distribution using a plurality of magnetic field generating elements and a plurality of magnetic field sensing element (orthogonal projection method) is described in WO 2023 / 079081 A1 the entirety of which is incorporated by reference. Of course, other known algorithms and / or method may be used for generating the predetermined magnetic field distribution. In this case, the magnetic field sensing element may be configured to only measure the magnetic field strength and not the orientation of the magnetic field.

[0045] It is to be noted that the magnetic sensing elements are not located within the volume in which the predetermined magnetic field is to be generated. Rather, the magnetic field sensing elements are arranged on the surface of the volume in which the predetermined magnetic field is to be generated. However, measurements of the magnetic field on the surface of the volume are sufficient for generating the predetermined magnetic field distribution inside the entire volume. This is further explained in WO 2023 / 079081 A1 . In other words, the magnetic field is measured only at the surface of the volume by the magnetic field sensing elements. This is sufficient for controlling the magnetic field inside the volume. When generating the predetermined magnetic field distribution or the predetermined magnetic field, the superposition of the measured magnetic field and the magnetic field generated by the plurality of the Mewburn Ref: 008669863

[0046] 1

[0047] magnetic generating elements may be within a predetermined range. An example of the predetermined range may be a range between 0 T and an upper threshold of the magnetic field strength. This example may correspond to nulling an external magnetic field below the upper threshold. Of course, the predetermined magnetic field distribution or the predetermined magnetic field may also correspond to homogeneous magnetic field inside the volume. In this case, the range may correspond to an amount of deviation from the predetermined homogeneous magnetic field strength. Again, the plurality of magnetic field generating element may be used for smoothing inconsistencies of an external magnetic field inside the volume.

[0048] For example, the range of variation from the predetermined magnetic field distribution can be 0.1 %, 0.5 %, 1%, 2 %, 3%, 4%, 5%, 10%, 15, or 20 %, between 0.1% to 20%, or between 0.1% to 10% of the strength and / or orientation of the predetermined magnetic field distribution. The predetermined magnetic field distribution may describe the strength and / or orientation of the predetermined magnetic field at any point inside the volume and / or on the surface of the volume. The predetermined magnetic field distribution may be provided a by continuous function or a discrete function that links each location (as an input of the function) with corresponding strength and / or orientation of the predetermined magnetic field (as output of the function).

[0049] The feedback control unit may include one or more processors and one or more memories storing programs and / or algorithms that are executed by the one and more processors. The feedback control unit may be provided for controlling each magnetic field generating element based on data and / or signals received from the magnetic field sensing elements. For example, each magnetic field sensing element can measure a strength and / or orientation of the magnetic field at the location of the respective magnetic field sensing element. This measured magnetic field may be the superposition of an external magnetic field and the magnetic field generated by the magnetic field generating elements. Each magnetic field sensing element may be configured to generate a signal and / or data indicative of the measured strength and / or orientation of the magnetic field at the location of the respective magnetic field sensing element. The feedback control unit may use the magnetic field as measured by the magnetic field sensing elements to appropriately control the magnetic field generating elements such that the measured magnetic field corresponds to the predetermined magnetic field or the predetermined magnetic field distribution in a predetermined range of variation. In this way, a feedback loop can be provided for adjusting the generated magnetic field to the predetermined magnetic field distribution. For example, the feedback control unit may use the magnetic field as measured by a magnetic field sensing element of each sensor-control unit to appropriately control corresponding one or more magnetic field generating elements (e.g. the magnet field generating element of the same sensor-source unit and / or the magnet field generating elements of adjacent sensor-source units) such that the measured magnetic field corresponds to the predetermined magnetic field (distribution) in a predetermined range of variation at the location of the magnetic field sensing element.

[0050] The bracket may be formed as any mechanical or structural component that is configured to support the magnetic field generating element and the magnetic field sensing element. The magnetic field sensing Mewburn Ref: 008669863

[0051] 8

[0052] element and the magnet field generating element may be permanently attached to the bracket. The bracket may be used for permanently or removably setting the distance between the magnetic field generating element and the magnetic field sensing element.

[0053] The bracket may be made from a material that does not interact with a magnetic field such that the bracket does not disturb the magnetic field that is generated by the magnetic field generating element and / or the bracket does not disturb the magnetic field that is measured by the magnetic field sensing element. The bracket may be made from a plastic material and / or a ceramic material.

[0054] The bracket may include a housing. The magnetic field generating element and / or the magnetic field sensing element may be arranged inside the housing. Thus, the bracket, optionally the housing of the bracket, may shield the magnetic field generating element and / or magnetic field sensing element from the environment of the bracket. The bracket may further include one or more wires for connecting the magnetic field generating element and / or magnetic field sensing element to the feedback control unit. The magnetic field generating element may be arranged on the housing and / or fixed to an outer surface of the housing.

[0055] The bracket may be configured to be attached to the outer surface of the device. In this way, the bracket can be used for attaching both the magnetic field sensing element and the magnetic field generating element to the device. The bracket may be attached to the device using an adhesive and / or welding. The bracket may also be attached to the device using one or more mechanical fastening means, such as screws.

[0056] The brackets and / or the sensor-source units may be completely separate from each other. Thus, there may not be any mechanical connections between individual brackets and / or sensor-source units. Thus, any sensor-source unit and / or any bracket may be individually placed around and / or attached to the device.

[0057] Optionally, the sensor-source units are orientated in such a way that the magnetic field sensing element is arranged between the volume and magnetic field generating element. For example, if the predetermined magnetic field is to be generated inside the volume and / or the device, the magnetic field sensing element is closer to the surface of the volume and / or the outer surface of the device compared to the magnetic field generating element. Alternatively, if the predetermined magnetic field is to be generated outside the device (e.g. for shielding the surroundings of the device from the magnetic field generated inside the device), the magnetic field generating element is arranged closer to the outer surface of the device compared to the magnetic field sensing element. In this case, the magnetic field sensing element is also arranged closer to the surface of the volume compared to the magnetic field generating element because the volume surrounds the outer surface of the device.

[0058] In an optional embodiment, the bracket includes an attachment portion for attaching the sensor-source unit to the device. Optionally, the magnetic field sensing element is arranged close to the attachment portion, e.g. closer to the attachment portion than the magnetic field generating element. Mewburn Ref: 008669863

[0059] 9

[0060] The attachment portion may include any surface and / or structure of the bracket with which the bracket can be attached to the device and / or placed around the device. For example, the attachment portion includes a flat surface of the bracket which can be used to attach the bracket to the device using an adhesive. Further, the attachment portion may include a flange for mechanically attaching the bracket to the device, for example using mechanical fastening means such as screws or the like.

[0061] Optionally, the magnetic field sensing element is arranged closer to the attachment portion compared to magnetic field generating element. This option may be used if the predetermined magnetic field is to be generated inside the device. Alternatively, the magnetic field generating element is arranged closer to the attachment portion compared to magnetic field sensing element. This option may be used if the predetermined magnetic field is to be generated outside the device.

[0062] The bracket may be an elongate component having a longitudinal axis. The attachment portion, the magnetic field generating element, and the magnetic field sensing element may be spaced from each other along the longitudinal axis.

[0063] In an optional embodiment, the bracket is adjustable and includes a movement mechanism and a locking mechanism. Optionally, the movement mechanism is configured to vary the distance between the magnetic field generating element and the magnetic field sensing element and / or the locking mechanism being configured to lock the distance between the magnetic field generating element and the magnetic field sensing element.

[0064] The inventors have found that the generation of the predetermined magnetic field (distribution) can be improved if the distance between the magnetic field generating element and the magnetic field sensing element for each sensor-source unit is at or close to an optimal distance. This optimal distance can be calculated using the same method as used for calculating the magnetic field to be generated by the plurality of sensor-source units. However, in this case, a further parameter of this optimisation process is the distance between the magnetic field sensing element and the magnetic field generating element. In other words, the algorithm for generating the magnetic field to be generated by the plurality of sensorsource units is optimised with regard to the distance between magnetic field generating element and a magnetic field sensing element.

[0065] Of course, other optimisation methods are possible. Such optimisation methods may vary the distance between the magnetic field generating element and the magnetic field sensing element for finding a maximum of conformity between the generated magnetic field and the predetermined magnetic field (distribution).

[0066] For example, when calculating the distance between the magnetic field generating element and the magnetic field sensing element for each sensor-source unit, no external magnetic field is assumed. Thus, the optimisation varies the generated magnetic field to match the predetermined magnetic field (distribution) by varying the distance between the magnetic field generating element and the magnetic field sensing element for each sensor-source unit. Mewburn Ref: 008669863

[0067] 10

[0068] The distance between the magnetic field generating element and the magnetic field sensing element may be set only once (for example after the installation of the plurality of sensor-source units) or at certain intervals. It is possible that the distance between the magnet defeat generating element and magnet field sensing element is not changed every time the predetermined field is generated. Rather, the method for generating the predetermined magnetic field distribution uses the distances set for each sensor-source unit for periodically or continuously calculating the magnetic field to be generated by the plurality of sensor-source units. For example, the feedback control unit may continuously or intermittently measure the magnetic field, runs the algorithm for determining the magnetic fields to be generated by each of the sensor-source units of the kit, and control the plurality of sensor-source units accordingly.

[0069] The movement mechanism of the bracket allows to vary the distance between the magnet field sensing element and magnetic field generating element. For example, the movement mechanism allows a change of the distance between the magnetic field generating element and magnetic field sensing element within a predetermined range which may correspond to the expected range of distances.

[0070] The locking mechanism may include any mechanical or any other means for removably or permanently setting / locking the distance between the magnetic field generating element and a magnetic field sensing element. For example, the locking mechanism may prevent the movement mechanism from further movement. For example, the locking mechanism may provide friction fit and / or include any other fastening means. Alternatively, the locking means may include an adhesive for locking the distance between the magnetic field generating element and the magnetic field sensing element.

[0071] In an optional embodiment, the movement mechanism is configured to linearly move the magnetic field generating element and the magnetic field sensing element relative to each other.

[0072] In this example, the distance between the magnetic field sensing element and the magnetic field generating element may be varied along a line which may correspond to the longitudinal axis of the bracket. In this way, there is only one dimension for changing the distance between the magnetic field sensing element and the magnetic field generating element. This may simplify the calculation of the distance between the magnetic field sensing element and the magnetic field generating element.

[0073] For example, the magnetic field generating element is movable relative to the attachment portion and the magnetic field sensing element is fixedly arranged relative to the attachment portion. This exemplary embodiment of the bracket can be used if the predetermined magnetic field (distribution) is to be generated inside the device such that the magnetic field sensing element is arranged close to or at the outer surface of the device. Thus, for setting the distance between the magnetic field sensing element and the magnetic field generating element, it is sufficient to vary the distance between the magnetic field generating element and the outer surface of the device.

[0074] In an alternative example, the magnetic field sensing element is movable relative to the attachment portion and the magnetic field generating element is fixedly arranged relative to the attachment portion. This exemplary embodiment of the bracket can be used if the predetermined magnetic field (distribution) is to be generated outside the device such that the magnetic field generating element is arranged close to Mewburn Ref: 008669863

[0075] 11

[0076] or at the outer surface of the device. Thus, for setting the distance between the magnetic field sensing element and the magnetic field generating element, it is sufficient to vary the distance between the magnetic field sensing element and the outer surface of the device.

[0077] In an optional embodiment, the movement mechanism includes two tubes telescopically movable relative to each other.

[0078] The bracket may include two tubes which each can be closed at one or both ends of a respective tube. The magnetic field sensing element and / or the magnetic field generating element can be arranged inside the tubes. For example, the magnetic field sensing element may be arranged inside a first tube of the two tubes and magnetic field generating element is arranged in or on a second tube of the two tubes. For example, each tube includes a bottom surface at which the magnetic field sensing element or the magnetic field generating element is arranged.

[0079] When varying the distance, the first tube may be telescopically inserted into the second tube or vice versa. The telescopic movement of the tubes may define the longitudinal direction of the bracket. The first tube and the second tube may form a common internal cavity in which the magnetic field sensing element and the magnet field generating element can be arranged.

[0080] In an optional embodiment, the plurality of sensor-source units includes various types of sensor-source units. Optionally, each type of sensor-source unit has a different fixed distance between the magnetic field generating element and the magnetic field sensing element.

[0081] In an optional embodiment, the step of arranging the plurality of sensor-source units includes selecting the type of sensor-source units that has a distance between the magnetic field generating element and the magnetic field sensing element that is closest to the calculated distance.

[0082] These optional embodiments refer to an alternative of the bracket having a movement mechanism.

[0083] Instead, the sensor-source units, optionally the brackets, provide a set of fixed distances between the magnetic field generating element and the magnetic field sensing element. For providing the possibility to vary the distance between respective magnetic field generating elements and magnet field sensing elements over the entire kit, several types of sensor-source units are provided. Each type of sensorsource unit has a distance between the magnetic field generating element and the magnetic field sensing element that is different to the distance of any other type of sensor-source unit of the kit. By choosing the appropriate type of sensor-source unit, the distance between the magnetic generating element and magnetic field sensing element can be set in accordance with the calculated distance as outlined above. Each kit may include 2, 3, 4, 5, 10, 15, 20, more different types of sensor-source units. For example, the difference in the distance between one type of sensor-source unit and another type of sensor-source unit may be 1 mm, 5 mm, 1 cm, 2 cm, or 5 cm. By providing a plurality of different types of sensor-source units, the distance between the magnetic field generating element and the magnetic field sensing element can be set in small intervals. This may provide a sufficiently close approximation of the actual distance compared to the calculated distance. Mewburn Ref: 008669863

[0084] 12

[0085] This embodiment has the advantage that no movement mechanism and locking mechanism is required for setting the distance. Instead, each sensor-source unit has a fixed distance while the entire kit may cover various distances. For example, each type of sensor-source unit may be labelled with a different colour, number, and / or letter.

[0086] The distance and / or location of each sensor-source unit may be calculated as outlined above. Then, when arranging each sensor-source unit, the appropriate type is chosen. This may be done in choosing that type of sensor-source unit whose distance is closest to the calculated distance. Thereafter, a sensorsource unit of the selected type is arranged around and / or attached to the device.

[0087] The distance may be calculated after each sensor-source unit is positioned and the position of each sensor-source unit is recorded and input into the feedback control unit. In this case, the distance is calculated for each sensor-source unit based on the information where each sensor-source unit is located.

[0088] Alternatively, the calculation of the distance may be simultaneously done to the calculation of the position of each sensor-source unit. In this case, the sensor-source units have not been placed around the device. Rather, the position and the distance are calculated for each sensor-source unit prior to the positioning thereof. This calculation may include the same method as outlined above with the modification that the distance and the position are parameters for optimisation. This approach may result in an improved predetermined magnetic field distribution. However, this approach requires a precise positioning of the sensor-source units.

[0089] The sensor-source units may be manufactured prior to the positioning around the device and / or the calculation of the position and / or distance of each sensor-source unit. The sensor-source units may be standardized components that can be mass-produced and / or irrespective of their application.

[0090] In an optional embodiment, the step of arranging the plurality of sensor-source units includes preparing the plurality of sensor-source units. Optionally, each sensor-source unit has a distance between the magnetic field generating element and the magnetic field sensing element that is equal to the calculated distance.

[0091] This is a further alternative and / or additional embodiment for setting the distance between the magnetic field sensing element and the magnetic field generating element. In this case, the sensor-source units are not prefabricated, i.e. the sensor-source units are manufactured after the calculation of the respective distances and / or positions. The sensor-source unit are prepared and / or manufactured after the distance between the magnetic field sensing elements and magnetic field generating elements is calculated for each sensor-source unit. In other words, each sensor-source unit may be bespoke. For example, the sensor-source units may be identical except for the distance between the magnetic field sensing element and magnetic field generating element. Each sensor-source unit may have the same shape or basic configuration while differing in the distance between the magnetic field generating element and the magnetic field sensing element. Mewburn Ref: 008669863

[0092] 13

[0093] In some examples, the sensor-source units may be manufactured by 3D printing. In this example, the attachment portion may be shaped and sized to match to respective outer surface section of the device. In an optional embodiment, the kit further includes a source unit comprising one or more magnetic field generating elements and the bracket to which the magnetic field generating element is fixedly attached. The source unit may be another component of the kit that differs from the sensor-source unit in that it only includes the magnetic field generating element but is free from the magnetic field sensing element. The source unit may be provided at locations where an additional magnetic field generating element is required or helpful for generating the predetermined magnetic field distribution. However, an additional magnetic field sensing element may not be required or may not provide an improved measurement of the magnetic field. In other words, the source unit is a component of the kit that may be provided for improving the generation of the predetermined magnetic field distribution without providing additional sensing capabilities.

[0094] The source unit may have the same optional features, characteristics and / or variants as discussed in connection with the sensor-source unit. For example, the source unit may have a fixed distance between the magnetic field generating element and the attachment portion. The distance may be individually set for each source unit as described above and / or different types of source units may be provided wherein each type of source unit has a different distance between the magnetic field generating element and the attachment portion. Further, the source unit may include the movement mechanism and the locking mechanism for varying the distance between the magnetic field generating element and the attachment portion.

[0095] The distance between the magnetic field generating element and the attachment portion may be calculated as described above, for example similar to the calculation of the distance between the magnetic field generating element and the magnetic field sensing element. This is because the distance between the magnetic field generating element and the magnetic field sensing element can be approximately equal to the distance between the magnetic generating element and the attachment portion.

[0096] In an optional embodiment, the kit further includes a second sensor-source unit comprising the magnetic field sensing element, at least two magnetic field generating elements, and the bracket to which the magnetic field generating elements and the magnetic field sensing element are fixedly attached.

[0097] The second sensor-source unit may be another component of the kit that differs from the sensor-source unit in that it includes two or more magnetic field generating elements. However, the second sensorsource unit includes only a single magnetic field sensing element. The second sensor-source unit may be provided at locations where an additional magnetic field generating element is required or helpful for generating the predetermined magnetic field distribution. However, an additional magnetic field sensing element (e.g. by providing two sensor-source units) may not be required or may not provide an improved measurement of the external magnetic field. In other words, the second sensor-source unit is a Mewburn Ref: 008669863

[0098] 14

[0099] component of the kit that may be provided for improving the generation of the predetermined magnetic field distribution without providing additional sensing capabilities.

[0100] The second sensor-source unit may have the same optional features, characteristics and / or variants as discussed in connection with the sensor-source unit. For example, the second sensor-source unit may have a fixed distance between the magnetic field generating element and the magnetic field sensing element. The distance may be individually set for each second sensor-source unit as described above and / or different types of second sensor-source units may be provided wherein each type of the second sensor-source unit has a different distance between the magnetic field generating element and the magnetic field sensing element. Further, the second sensor-source unit may include the movement mechanism and the locking mechanism for varying the distance between the magnetic field generating element and the magnetic field sensing element.

[0101] The distance between the magnetic field generating element and the magnetic field sensing element may be calculated as described above, for example similar to the calculation of the distance between the magnetic field generating element and the magnetic field sensing element of the sensor-source unit. In an optional embodiment, one or more sensor-source units, one or more of the second sensor-source units, and / or one or more of the source units are connected to each other.

[0102] With the other examples, the sensor-source units, the second sensor-source units and / or the source units are separate components, e.g. none of these components is mechanically connected to another component. However, with this example, the sensor-source units, the second sensor-source units, and / or the second sensor-source units are mechanically connected to each other. Optionally, all units of the kit are mechanically connected to each other. For example, the kit forms a web, carpet, layer or single structure that is made up of the plurality of the sensor-source units, the second sensor-source units and / or the source units. This single structure of the kit may be arranged to cover the device.

[0103] Each unit of the kit may be connected to 1 , 2, 3, 4, 5, 6, or more other units of the kit. For example each bracket may include a connection portion with which the respective unit is connected to another unit. 1 , 2, 3, 4, 5, 6, or more connection portions may be provided with each bracket. The connection portion may be arranged close to the magnetic field sensing element, the magnetic field generating element, or the attachment portion.

[0104] The connection portion may provide a permanent or removable connection of the unit to a respective other unit. In this way, not every unit may be attached to the device. Rather, some of the units may be only supported by the connection to other units that are attached to the device.

[0105] The magnetic field sensing elements of the various types of units may form a first layer and / or the magnetic field generating elements of the various types of units may form a second layer that may extend approximately parallel to the first layer. The distance between the first layer and the second layer and / or the distance between the magnetic field sensing element and the magnetic field generating element can be varied, for example using the movement mechanism and the locking mechanism. Mewburn Ref: 008669863

[0106] 15

[0107] In an optional embodiment, the magnetic field generating elements of one or more sensor-source units, one or more of the second sensor-source units, and / or one or more of the source units are connected to each other and each magnetic field sensing element is movable relative to the connected magnetic field generating elements.

[0108] With this optional embodiment, the units of the kit are connected to each other close to or at the magnetic field generating elements. For example, the connection portion is arranged close to or at the magnetic field generating element. The units may include the movement mechanism and the locking mechanism such that the magnetic field sensing elements are movable relative to the magnetic generating elements. In other words, the layer of magnetic field sensing elements is movable relative to the layer of magnetic field generating elements. In this way, the distance between the magnetic field generating elements and the magnetic field sensing elements can be appropriately set while the units are connected to each other. As the units are connected to each other close to the magnetic field generating elements, only the magnetic field sensing elements can be moved while the magnetic field generating elements may remain at the same position (or vice versa).

[0109] In an optional embodiment, the magnetic field generating elements are pivotably connected to each other. The connection portion may include a hinge for allowing pivoting the units relative to each other. The connection portion may be pivotable and arranged or located close to or at the magnetic field generating element. In this way, the second layer of the magnetic field generating elements may be flexible. Further, the kit of interconnected units may be configured to be wrapped around the device because the individual units pivotably connected to each other. The kit can be configured to adapt to the surface of the device and / or the volume.

[0110] In an optional embodiment, the magnetic field generating elements are rigidly connected to each other for providing a scaffold around the device.

[0111] In this example, the kit is not configured to adapt to the surface of the device and / or the volume. Rather, the rigid connection between the individual units provides a rigid scaffold which can be arranged to cover or to be put over the device. However, it is still possible to vary the distance between the magnetic field sensing elements and the magnetic field generating elements to optimise the generation of the predetermined magnetic field distribution.

[0112] The shape and size of the scaffold may be adapted and / or varied depending on the use case.

[0113] An example of the invention will be summarized in the following:

[0114] Unlike examples of the prior art, the volume which is shielded from an external magnetic field (more generally the volume in which the predetermined magnetic field (distribution) is generated) is not a sphere, rather a complex shape. In some examples, the feedback sensors (an example of the magnetic field sensing element) need to be with a certain distance from the coil (an example of the magnetic field generating element) for improving the shielding properties. This consideration is used to create a universal module (an example of the sensor-source unit) that includes the feedback sensor and an adjustable coil support (an example of the bracket). This type of shielding can be easily applied to Mewburn Ref: 008669863

[0115] 16

[0116] different types of equipment like electron microscopes, XPS systems, or even to shield satellites from magnetic storms. Magnetic storms can damage powerlines, communication satellites (including GPS) leading to billion dollars magnitude losses. The magnetic field variation during magnetic storm can range from tens of nT to pT.

[0117] The proposed kit can be applied to a device with complex shapes and size, which makes it suitable as magnetic storm protection.

[0118] Similar to the compensation of a magnetic field (e.g. shielding an external magnetic field), the kit could be also used to generate a magnetic field on demand. Electron microscopes and / or XPS system might use magnetic fields as a part of ion beam optics, for example to work with spin polarised ions or electrons, where the magnetic field is used to keep polarisation state. Thus, the kit may be a tool for generating bespoke magnetic fields.

[0119] To generate the predetermined magnetic field distribution within defined volume, the magnetic feedback sensors are placed offset to the coils for generating a uniform magnetic field. It was experimentally discovered by the inventors that a gradient field is generated if there is offset from an ideal position. This magnetic field gradient may be caused by magnetisation of the amorphous metal inside the sensor. When the array of coils was moved and / or rotated, the gradient remained the same. After correct positioning of the sensors, the gradient was removed. Thus, placing the sensors at the correct position and / or setting the correct distance between the sensors and coils can be an important factor for generating the predetermined magnetic field distribution.

[0120] One of the important application of the kit described herein are Magnetic resonance imaging (MRI) gradient coils. The proposed kit can not only deliver precise predetermined magnetic field gradients inside the MRI but also can shield it from the environmental distortion.

[0121] The kit can also be used to generate on demand magnetic fields as a protection for spaceships. In this case superconducting coils may be used to generate strong magnetic field around the spaceship to deflect ionized particles, essentially in the same way as the earth magnetic field protects the earth from ionized particles. The kit can provide smaller and more efficient protection compared to existing solutions. The way how the shielding is applied includes distributing universal modules having of feedback sensor and coil, whereby the distance between the feedback sensor and the coil is adjustable. The distance is within a certain distance for solution to be optimal. The kit allows to distribute shielding coils over complex shapes, then adjust distance to the feedback sensors distances.

[0122] One exemplary purpose of the kit is to cover general shielding applications. There is a broad application of the invention as a protection from magnetic storms, for power lines, telecommunication satellites. The kit can also be used to generate magnetic field or / and magnetic field gradient in complex shapes.

[0123] The invention includes the combination of the aspects and preferred features described except where such a combination is clearly impermissible or expressly avoided. Any (optional) method step disclosed herein may be understood as a process and / or feature that the feedback control unit and / or the apparatus Mewburn Ref: 008669863

[0124] 17

[0125] is configured to carry out. Conversely, any optional feature of the kit and / or the apparatus may be understood as being a corresponding method step.

[0126] Summary of the Figures

[0127] Embodiments and experiments illustrating the principles of the invention will now be discussed with reference to the accompanying figures in which:

[0128] Figure 1 shows a schematic view of an apparatus for generating a predetermined magnetic field distribution in a predetermined volume.

[0129] Figure 2 shows a cross-sectional view (left), a cross-sectional and perspective view (middle), and a perspective views of a sensor-source unit of the apparatus of Figure 1 .

[0130] Figure 3 shows perspective views of a device (left) and a kit of sensor-source units attached to the device (right).

[0131] Figure 4 shows perspective views of magnetic field generating elements (left) and of magnetic field sensing elements (right) of the sensor-source units of Figure 3.

[0132] Figure 5 shows results of calculations of a magnetic field at the device of Figure 3 in two orientations with respect to a geomagnetic field of 50 pT.

[0133] Figure 6 shows results of calculations of a magnetic field at the device of Figure 3 wherein the top left graph shows the magnetic field in a range between 0 to 100 pT in a geomagnetic field of 50 pT, the bottom left graph shows the corresponding vector plot of the magnetic fields, the top right graph shows the magnetic field in a range between 0 to 100 pT without the geomagnetic field, and the bottom right graph shows the corresponding vector plot of the magnetic fields.

[0134] Figure 7 shows a block diagram illustrating steps of a method for generating a predetermined magnetic field in a predetermined volume.

[0135] Figure 8 shows a block diagram illustrating steps of another method for generating a predetermined magnetic field distribution in a predetermined volume.

[0136] Figure 9 shows a further embodiment of the kit in which the magnetic field generating elements are connected to each other.

[0137] Figure 10 shows results of calculations of a magnetic field at the kit of Figure 9.

[0138] Figure 11 shows a mesh of polygons, wherein each polygon defines a position of the magnetic field generating element of the kit of Figure 7 (top left) and each polygon defines a position of the magnetic field sensing element of the kit of Figure 7 (top right).

[0139] Figure 12 shows a cross-sectional view of a source unit of the apparatus of Figure 1. Mewburn Ref: 008669863

[0140] 18

[0141] Figure 13 shows a cross-sectional view a second sensor-source unit of the apparatus of Figure 1 .

[0142] Detailed Description of the Invention

[0143] Aspects and embodiments of the present invention will now be discussed with reference to the accompanying figures. Further aspects and embodiments will be apparent to those skilled in the art. All documents mentioned in this text are incorporated herein by reference.

[0144] Figure 1 shows an apparatus 10 for generating a predetermined magnetic field distribution in a predetermined volume in relation to a device 20 (not shown in Figure 1). The apparatus 10 includes a kit 12 and a feedback control unit 14. The kit 12 includes a plurality of sensor-source units 100 each of which is connected to the feedback control unit 14 by a respective cable 110.

[0145] As apparent from Figure 2, the sensor-source unit 100 includes a magnetic field generating element 102, a magnetic field sensing element 104, and a bracket 106. The magnetic field generating element 102 is provided for generating a magnetic field and / or may include one or more coils which are connected to the cable 110 for supplying electric currents to the magnetic field generating element 102. The magnetic field sensing element 104 is configured to detect the strength and / or orientation of the magnetic field at the location of the magnetic field sensing element 104. The magnetic field sensing element 104 may include one or more detectors which are capable of measuring a magnetic field, e.g. a Hall detector and / or a magneto-resistive sensor. In some examples the magnetic field sensing element 104 is capable of measuring the magnetic field in three dimensions, such as the x-, y-, and z-coordinate of the magnetic field. To this end, the magnetic field sensing element 104 may include one or more giant magnetoresistance (GMR) sensors and / or one or more tunnel magnetoresistance (TMR) sensors.

[0146] The magnetic field generating element 102 and magnetic field sensing element 104 are each permanently or non-removably attached to the bracket 106. Thus, the bracket 106 supports both the magnetic field generating element 102 and magnetic field sensing element 104. The bracket 106 includes an attachment portion 108 for connecting the bracket 106 to the device 20. For example, an adhesive may be provided at the attachment portion 108 for attaching the bracket 106 to the device 20.

[0147] Alternatively, welding, such as spot welding, may be used for attaching the bracket 106 to the device 20. In the embodiment shown in Figure 2, the bracket 106 is configured to linearly move the magnetic field generating element 102 relative to the magnetic field sensing element 104. In words, the bracket 106 is configured to vary the distance between the magnetic field generating element 102 and the magnetic field sensing element 104. As an example, the bracket 106 includes two tubes that can be telescopically moved relative to each other. The two tubes are an example of a movement mechanism which allows to move the magnetic field generating element 102 and magnetic field sensing element 104 relative to each other. The tubes may be fixed to each other at a desired position for setting the distance between the magnetic field generating element 102 and magnetic field sensing element 104. For example, an Mewburn Ref: 008669863

[0148] 19

[0149] adhesive and / or a mechanical fastening element (such as a screw) can be used (not shown in Figure 2). The adhesive and / or a mechanical fastening element are examples of a locking mechanism for permanently or removably locking the movement mechanism. The magnetic field generating element 102 is attached to one of the tubes and the magnetic field sensing element 104 is attached to the other one the tubes.

[0150] The magnetic field sensing element 104 can be arranged inside the bracket 106, optionally the tube. The magnetic field generating element 102 be arranged on the outer surface of the bracket 106, optionally the tube.

[0151] Turning back to Figure 1 , each magnetic field generating element 102 and each magnetic field sensing element 104 is electrically and / or electronically connected to the feedback control unit 14 via a respective cable 110. In this way, the feedback control unit 14 can read the strength and / orientation of the magnetic field at the location of a respective magnetic field sensing element 104. Further, the feedback control unit 14 can selectively supply electrical currents to each of the magnetic field generating elements 102. In particular, the feedback control unit 14 is configured to vary the strength of the electric current to be supplied to each magnetic field generating element 102 for varying the magnetic fields generated by each magnetic field generating element 102. The sum or superposition of each generated magnetic field may be considered as the magnetic field that is generated by the kit 12 of the sensor-source units 100.

[0152] The strength and / or orientation of the generated magnetic field may be determined based on the magnetic field measured by the magnetic field sensing elements 104. The feedback control unit 14 may be configured to generate a predetermined magnetic field or predetermined magnetic field distribution within a predetermined volume. The predetermined magnetic field distribution may be defined by the strength and / orientation of the magnetic field at all points within the volume or at certain sections or areas within the volume. The predetermined magnetic field distribution may be the superposition of the magnetic field generated by the apparatus 10 and an external magnetic field, such as a magnetic field generated by an instrument close to the apparatus 10 or the magnetic field of the earth (geomagnetic field). The predetermined magnetic field (distribution) may be essentially a magnetic field free volume. In other words, the predetermined magnetic field (distribution) may be a magnetic field in a range close to 0. Thus, the apparatus 10 may be used for nulling the external magnetic field inside the volume. In this case, the magnetic field generated by the apparatus 10 is intended to cancel the external magnetic field. In other embodiments, the apparatus 10 may be provided to generate a predetermined magnetic field distribution inside the device 20 or cancel a magnetic field that is generated by the device 20.

[0153] The feedback control unit 14 may apply an orthogonal projection method for calculating the magnetic fields generated by the plurality of magnetic field generating elements 102 based on the readings of the magnetic field sensing elements 104. An example of such an orthogonal projection method is described in WO 2023 / 079081 A1 . It is also possible that other methods or algorithms are used for calculating the magnetic field to be generated and to control the magnetic field generating elements 102 based on the calculated magnetic field. Mewburn Ref: 008669863

[0154] 20

[0155] The feedback control unit 14 can include a connection box 112, an analog-to-digital (ADC) converter 114, a central processing unit (CPU) 116, a current source 118, and / or a digital-to-analog (DAC) converter 120. The connection box 112 can be configured to route the readings of the various magnetic field sensing elements 104 to the central processing unit 116 via the analog-to-digital 114. Further, the connection box 112 can also be configured to route the electrical currents for powering the magnetic field generating elements 102 generated by the current source 118 to the respective magnetic field generating elements 102. The connection box 112 may include one or more mechanical or electrical switches for appropriately connecting and disconnecting the sensor-source units 100 with the feedback control unit 14. The analog-to-digital converter 114 may be configured to convert analog signals generated by the magnetic field sensing elements 104 into digital signals which can be processed by the central processing unit 116. Conversely, the digital-to-analog converter 120 can be configured to convert digital signals generated by the central processing unit 116 into analog signals for controlling the current source 118. The central processing unit 116 may include one or more processors and one or more memories which store programs and / or algorithms that are executed by the one or more processors. The programs and / or algorithms may specify the method for generating the magnetic field based on the readings of the magnetic field sensing elements 104. Exemplary methods will be further described in connection with Figures 7 and8. Commonly known central processing units, such as a computer, may be used.

[0156] The current source 118 may include one or more components that generate an electric current based on an analog signal from the digital-to-analog converter 120 which is generated in response to a digital signal from the central processing unit 116.

[0157] Figure 3 shows an example of the device 20 - an Ultra High Vacuum chamber that requires magnetic shielding, for example for an XPS electron microscope. As apparent from Figure 3, the outer surface of the device 20 is not flat. Rather, the outer surface of the device 20 includes several edges. For nulling external magnetic fields, the plurality of sensor-source units 100 are attached to the outer surface of the device 20. To this end, the brackets 106 are attached to the outer surface of the device 20 via the attachment portion 108.

[0158] As apparent from Figure 4, the magnetic field generating elements 102 and the magnetic field sensing elements 104 follow or mimic the outer surface of the device 20. Further, it is apparent from Figure 4 that each magnetic field generating element 102 is set at a specific distance from the respective magnetic field sensing element 104.

[0159] Figure 5 shows a heat map of the magnetic field strength in and around the device 20 of Figure 3.

[0160] Thereby, the dark colour corresponds to 50% of geomagnetic field ( 25 pT) and the white-grey colour corresponds to no magnetic field. It is apparent from Figure 5 that the geomagnetic field (as represented by the arrow 204) outside the device 20 is effectively cancelled inside the device 20 or in a volume that corresponds to the volume of the device (an example of the predetermined volume). The predetermined magnetic field (distribution) is the magnetic field inside the device 20 and, in this case, includes a range Mewburn Ref: 008669863

[0161] 21

[0162] around 0 T. It is further apparent from Figure 5 that effective cancellation of the geomagnetic field is provided irrespective of the orientation of the device 20 with regard to the geomagnetic field.

[0163] Figure 6 shows heat maps of the magnetic field generated by the magnetic field generating elements 102 of Figure 5 with a geomagnetic field of 50 pT (top left map) and without the geomagnetic field (top right map). In the top left map, the dark colour corresponds to magnetic field strength of 100 pT and the whitegrey colour corresponds no magnetic field. It is apparent from the top left map of Figure 6 that the magnetic field generated by the magnetic field generating elements 102 is generated in an area that follows the outer surface of the device 20. Further, the generated magnetic field is approximately constant inside the device 20 and little or no magnetic field of the generated magnetic field is present outside the device 20 (as it is cancelled by the external magnetic field). As the geomagnetic field is approximately homogeneous inside the device 20 and the magnetic field generating elements 102 generate an approximately homogeneous magnetic field inside the device 20, an effective cancellation of the external magnetic field can be achieved inside the device 20. This is readily apparent from the graph on the bottom which shows a vector stream plot of the magnetic fields. The external magnetic field, for example geomagnetic field, does not penetrate the device 20 providing effective shielding of the external magnetic field. This is due the generated magnetic fields which shield the device 20 by guiding the external magnetic field around the device 20.

[0164] In the top right map of Figure 6, the dark colour corresponds to magnetic field strength of 100 pT and the white-grey colour corresponds no magnetic field. This heat map is based on the consideration of no external magnetic field and refers to the generation of a bespoke magnetic field inside the device 20. It is apparent from the top right map of Figure 6 that the magnetic field generated by the magnetic field generating elements 102 is generated in an area that follows the outer surface of the device 20. Further, the generated magnetic field is approximately constant inside the device 20.

[0165] A method for generating a predetermined magnetic field distribution in a predetermined volume, for example inside device 20, using the apparatus 10 of Figure 1 is described in connection with Figure 7. In step S1 , the sensor-source units 100 of the kit 12 are arranged around the device 20, for example by attaching the sensor-source units 100 to the outer surface of the device 20 using the attachment portion 108 as described above. Step S1 may include recording the positions where each sensor-source unit 100 is located.

[0166] In step S2, the distance between the magnetic field generating element 102 and the magnetic field sensing element 104 is set for each sensor-source unit 100. The distance can be set by telescopically moving the tubes of the brackets 106 relative to each other and fixing the relative position once the desired distance between the magnetic field generating element 102 and the magnetic field sensing element 104 is reached, for example using an adhesive.

[0167] The distance to be set in step S2 may be calculated using the above-described method for calculating the magnetic field whereby the method is modified in that the distance between the magnetic field generating element 102 and the magnetic field sensing element 104 is a parameter for the calculation. In other Mewburn Ref: 008669863

[0168] 22

[0169] words, the magnetic field to be generated is optimised with regard to the distance between the magnetic field generating element 102 and the magnetic field sensing element 104. For this calculation, a constant or no external magnetic field can be used. Thus, the optimisation relates to varying the magnetic field to be generated by the magnetic field generating elements 102 to match the predetermined magnetic field distribution by varying the distance between the magnetic field generating element 102 and the magnetic field sensing element 104 for each sensor-source unit 100.

[0170] Steps S1 and S2 may be considered corresponding to the preparation of the apparatus 10 prior to the generation of the magnetic field which is done in steps S3 and S4.

[0171] In step S3, the current magnetic field is measured using the magnetic field sensing elements 104. The measured magnetic field strength and / or orientation is forwarded to the feedback control unit 14 as described above.

[0172] The feedback control unit 14 may execute step S4 in which the magnetic field to be generated by the plurality of sensor-source units 100 is calculated as outlined above. In one example, the magnetic fields that are generated by each of the magnetic field generating elements 102 is calculated and converted into an electric current with which the corresponding magnetic field generating element 102 is to be powered. Subsequently, the electrical currents are supplied to the respective magnetic field generating elements 102.

[0173] Steps S3 and S4 may be continuously or periodically executed / repeated to maintain the predetermined magnetic field distribution inside the device 20 over the time of operation.

[0174] Another method for generating a predetermined magnetic field distribution in a predetermined volume, for example inside device 20, using the apparatus 10 of Figure 1 is described in connection with Figure 8. In step S1 , the distance between the magnetic field generating element 102 and the magnetic field sensing element 104 is calculated for each sensor-source unit 100 at their respective locations on the device 20. The distance may be calculated using the above-described method for calculating the magnetic field whereby the method is modified in that distance between the magnetic field generating element 102 and the magnetic field sensing element 104 is a parameter for the calculation. In other words, the magnetic field to be generated is optimised with regard to the distance between the magnetic field generating element 102 and the magnetic field sensing element 104. For this approach, the positions of the magnetic field generating element 102 can be predetermined, e.g. by providing an even distribution of the magnetic field generating element 102 on the outer surface of the device 20.

[0175] In step S2, the sensor-source units 100 of the kit 12 are arranged around the device 20, for example by attaching the sensor-source units 100 to the outer surface of the device 20 using the attachment portion 108 as described above. Step S2 also includes setting the distance between the magnetic field generating element 102 and the magnetic field sensing element 104 as calculated in step S1. The distance can be set by telescopically moving the tubes of the brackets 106 relative to each other and fixing the relative position once the desired distance between the magnetic field generating element 102 and the magnetic field sensing element 104 is reached, for example using an adhesive. Mewburn Ref: 008669863

[0176] 23

[0177] In a variant of the method of Figure 8, both the position of the sensor-source units 100 on the surface of the device 20 and the distance between the magnetic field generating element 102 and the magnetic field sensing element 104 are calculated prior to the arrangement of the sensor-source units 100 on the surface of the device 20. Thus, the optimisation of the distance can be simultaneously executed with the calculation of the position of the respective sensor-source units 100. In this case, the distance between the magnetic field generating element 102 and the magnetic field sensing element 104 as well as the positions of the respective sensor-source units 100 are two parameters that are optimised using the method described above. In this case, this step S1 is executed before the sensor-source units 100 are attached to the device 20.

[0178] Step S2 of arranging the sensor-source units 100 on the surface of the device 20 may include preparing the plurality of sensor-source units 100 having a distance between the respective magnetic field generating elements 102 and the respective magnetic sensing elements 104 instead of setting this distance. To this end, each one of the sensor-source units 100 may be specifically manufactured with the distance between the magnetic field generating element 102 and the magnetic field sensing element 104 as calculated in step S1 . For example, the brackets 106 may be 3D printed having a size and configuration such that the bracket 106 provides the calculated distance between the magnetic field generating element 102 and the magnetic field sensing element 104 when the elements are attached to the bracket 106. In this case, the bracket 106 may not include the movement mechanism as described in connection with Figure 2.

[0179] Alternatively, the kit 12 includes a plurality of different types of sensor-source units 100. Each type of sensor-source unit 100 includes a different distance between the magnetic field generating element 102 and the magnetic field sensing element 104. For example, each sensor-source unit 100 includes the same magnetic field sensing element 104, the same magnetic field generating element 102, and the bracket 106 of the same basic configuration. However, the length of the bracket 106 varies with each type of sensor-source unit 100. In this case, step S2 includes selecting the type of sensor-source unit 100 whose distance between the magnetic field generating element 102 and the magnetic field sensing element 104 is closest to the calculated distance.

[0180] Steps S1 and S2 may be considered corresponding to the preparation of the apparatus 10 prior to the generation of the magnetic field which is done in steps S3 and S4.

[0181] In step S3, the current magnetic field is measured using the magnetic field sensing elements 104. The management magnetic field strength and / or orientation is forwarded to the feedback control unit 14 as described above.

[0182] The feedback control unit 14 may execute step S4 in which the magnetic field to be generated by the plurality of sensor-source units 100 is calculated as outlined above. In one example, the magnetic fields that are generated by each of the magnetic field generating elements 102 is calculated and converted into an electric current with which the corresponding magnetic field generating element 102 is to be powered. Subsequently, the electrical currents are supplied to the respective magnetic field generating elements 102. Mewburn Ref: 008669863

[0183] 24

[0184] Steps S3 and S4 may be continuously or periodically executed to maintain the predetermined magnetic field distribution inside the device 20 over the time of operation.

[0185] Figure 9 shows another embodiment of the kit 12. With this embodiment, the sensor-source units 100 are connected to each other and form a blanket or layer of sensor-source units 100. In Figure 9, the magnetic field generating elements 102 are connected to each other and / or overlap with each other. The bracket 106 and the magnetic field sensing elements 104 are not readily visible in Figure 9. Rather, the positions of the magnetic field sensing elements 104 are schematically shown in right-hand drawing in Figure 11 wherein each polygon 272 shows the position of a single magnetic field sensing element 104. The lefthand drawing in Figure 11 shows the positions of the magnetic field generating elements 102 wherein each polygon 270 shows the positions of a single magnetic field generating element 102. It is apparent from Figure 11 that the plurality of magnetic field sensing elements 104 form a layer that extends parallel to a layer formed by the plurality of magnetic field generating elements 102. The layer of magnetic field generating elements 102 covers the layer of the magnetic field sensing elements 104. The distance between the layer of the magnetic field generating elements 102 and layer of the magnetic field sensing elements 104 is set by the respective brackets 106 supporting the magnetic field generating elements 102 and the magnetic field sensing elements 104.

[0186] The individual sensor-source units 100 are connected to each other. In some examples, the individual magnetic field generating elements 102 are connected to each other. In the example of Figure 9, the connection between individual sensor-source units 100 is rigid such that the plurality of sensor-source units 100 form a rigid structure which may be positioned to cover the device 20 (not shown in Figure 9). Alternatively, the connection between individual sensor-source units 100 is flexible. For example, the respective magnetic field generating elements 102 are pivotable relative to each other. In this case, the kit 12 of interconnected sensor-source units 100 can be wrapped around the device 20.

[0187] Figure 10 shows a heatmap of the magnetic field strength of the kit 12 of Figure 9 which includes 1134 magnetic field generating elements 102. The dark colour indicates a magnetic field strength of 100 pT and white-grey colour indicates no magnetic field. The magnetic field generating elements 102 and the magnetic field sensing elements 104 are not arranged with high precision. For example, the positions of the magnetic field generating elements 102 and the magnetic field sensing elements 104 are not calculated prior to their arrangement. Nevertheless, a relatively homogeneous magnetic field can be generated using the calculation method described herein. This demonstrates the flexibility and wide applicability of the kit 12 and the methods for generating the predetermined magnetic field distribution described herein.

[0188] The features disclosed in the foregoing description, or in the following claims, or in the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for obtaining the disclosed results, as appropriate, may, separately, or in any combination of such features, be utilised for realising the invention in diverse forms thereof.

[0189] Figure 12 shows a source unit 130 which may also be a component of the kit 12. The source unit 130 may include the magnetic field generating element 102 and the bracket 106. The source unit 130 may not Mewburn Ref: 008669863

[0190] 25

[0191] include the magnetic field sensing element 104. In the example shown in Figure 12, the source unit 130 has the same configuration as the sensor-source unit 100 except for the presence of the magnetic field sensing element 104. The source unit 130 may be provided at positions on the outer surface of the device 20 where the generation of the magnetic field is helpful for providing the predetermined magnetic field distribution. However, the presence of a further magnetic field sensing element 104 may not be necessary for increasing the precision of the measurement of the magnetic field. For example, the magnetic field at the position of the source unit 130 may be approximated by the measurements of the magnetic field by adjacent sensor-source units 100.

[0192] Figure 13 shows a second sensor-source unit 140 which may also be a component of the kit 12. The second sensor-source unit 140 may include two magnetic field generating elements 102, a single magnetic field sensing element 104, and / or the bracket 106. In the example shown in Figure 13, the source unit 130 has the same configuration as the sensor-source unit 100 except for the presence of a second magnetic field generating element 102. The two magnetic field generating elements 102 may be arranged on the same side of the second sensor-source unit 140.

[0193] The second sensor-source unit 140 may be provided at positions on the outer surface of the device 20 where the generation of two magnetic fields is helpful for providing the predetermined magnetic field distribution. However, the presence of a further magnetic field sensing element 104 may not be necessary for increasing the precision of the measurement of the magnetic field. For example, the magnetic field at the position of the source unit 140 may be approximated by the measurements of the magnetic field by adjacent sensor-source units 100. Thus, the second sensor-source unit 140 may be provided instead of two sensor-source units 100 in circumstances where a single magnetic field sensing element 104 suffices and / or is simpler to attach two magnetic field generating elements 102 to the device 20 using a single bracket 106.

[0194] While the invention has been described in conjunction with the exemplary embodiments described above, many equivalent modifications and variations will be apparent to those skilled in the art when given this disclosure. Accordingly, the exemplary embodiments of the invention set forth above are considered to be illustrative and not limiting. Various changes to the described embodiments may be made without departing from the spirit and scope of the invention.

[0195] For the avoidance of any doubt, any theoretical explanations provided herein are provided for the purposes of improving the understanding of a reader. The inventors do not wish to be bound by any of these theoretical explanations.

[0196] Any section headings used herein are for organizational purposes only and are not to be construed as limiting the subject matter described herein.

[0197] Throughout this specification, including the claims which follow, unless the context requires otherwise, the word “comprise” and “include”, and variations such as “comprises”, “comprising”, and “including” will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps. Mewburn Ref: 008669863

[0198] 26

[0199] It must be noted that, as used in the specification and the appended claims, the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise. Ranges may be expressed herein as from “about” one particular value, and / or to “about” another particular value. When such a range is expressed, another embodiment includes from the one particular value and / or to the other particular value. Similarly, when values are expressed as approximations, by the use of the antecedent “about,” it will be understood that the particular value forms another embodiment. The term “about” in relation to a numerical value is optional and means for example + / - 10%.

[0200] References

[0201] A number of publications are cited above in order to more fully describe and disclose the invention and the state of the art to which the invention pertains. Full citations for these references are provided below. The entirety of each of these references is incorporated herein.

[0202] WO 2023 / 079081 A1

Claims

Mewburn Ref: 00866986327Claims:1 . A kit for generating a predetermined magnetic field distribution in a predetermined volume in relation to a device, comprising:a plurality of sensor-source units configured to be placed around the device,wherein each sensor-source unit includesa magnetic field generating element for generating a respective magnetic field in the volume, the respective magnetic field being configured to contribute to the predetermined magnetic field distribution generated by the kit,a magnetic field sensing element for sensing a magnetic field at a surface of the volume, anda bracket to which the magnetic field generating element and the magnetic field sensing element are fixedly attached.

2. The kit of claim 1 , wherein the bracket is adjustable and includes a movement mechanism and a locking mechanism, the movement mechanism being configured to vary the distance between the magnetic field generating element and the magnetic field sensing element and the locking mechanism being configured to lock the distance between the magnetic field generating element and the magnetic field sensing element.

3. The kit of claim 2, wherein the movement mechanism is configured to linearly move the magnetic field generating element and the magnetic field sensing element relative to each other.

4. The kit of claim 3, wherein the movement mechanism is configured to linearly move the magnetic field generating element and the magnetic field sensing element in a telescopic manner.

5. The kit of claim 4, wherein the movement mechanism includes two or more tubes telescopically movable relative to each other.

6. The kit of any one of the claims 2 to 5, wherein the bracket includes an attachment portion for attaching the sensor-source unit to the device,wherein the magnetic field sensing element is arranged close to the attachment portion, and wherein the magnetic field generating element is movable relative to the attachment portion.Mewburn Ref: 008669863287. The kit of claim 1 , wherein the plurality of sensor-source units includes various types of sensorsource units,wherein each type of sensor-source unit has a different fixed distance between the magnetic field generating element and the magnetic field sensing element.

8. The kit of any preceding claim, wherein the magnetic field generating element comprises one or more electrically conductive coils for generating the magnetic field.

9. The kit of claim 8, wherein the conductive coil includes a longitudinal axis,wherein the magnetic field sensing element is arranged on the longitudinal axis.

10. The kit of any preceding claim, wherein the kit further includes a source unit comprising the magnetic field generating element and the bracket to which the magnetic field generating element is fixedly attached.

11. The kit of any preceding claim, wherein the kit further includes a second sensor-source unit comprising the magnetic field sensing element, at least two magnetic field generating elements, and the bracket to which the magnetic field generating elements and the magnetic field sensing element are fixedly attached.

12. The kit of any preceding claim, wherein one or more of the sensor-source units, one or more of the second sensor-source units, and / or one or more of the source units are connected to each other.

13. The kit of claim 12 when depending on any one of the claims 2 to 5, wherein the magnetic field generating elements of the sensor-source units, one or more of the second sensor-source units, and / or one or more of the source units are connected to each other and each magnetic field sensing element is movable relative to the connected magnetic field generating elements.

14. The kit of claim 13, wherein the magnetic field generating elements are pivotably connected to each other.Mewburn Ref: 0086698632915. The kit of claim 13, wherein the magnetic field generating elements are rigidly connected to each other for providing a scaffold around the device.

16. An apparatus for generating predetermined magnetic field distribution in a predetermined volume in relation to a device, comprisingthe kit of any preceding claim,a feedback control unit for controlling the respective magnetic fields generated by each of the plurality of magnetic field generating elements in response to the magnetic field sensed by the plurality of magnetic field sensing elements by controlling the magnetic field generating elements such that the magnetic field detected by respective magnetic field sensing elements is within a range corresponding the predetermined magnetic field distribution.

17. The apparatus of claim 16, wherein the feedback control unit is configured to reduce an external magnetic field for not exceeding a pre-set threshold value corresponding to a pre-set nulling of the external magnetic field within the volume.

18. Use of the kit of any one of the claims 1 to 15 or the apparatus of claim 16 or 17 for a satellite and / or an instrument containing a magnetic field sensor.

19. Method for generating a predetermined magnetic field distribution in a predetermined volume in relation to a device, comprising the steps ofarranging a plurality of sensor-source units around the device, each sensor-source unit including a magnetic field generating element for generating a respective magnetic field in the volume, the respective magnetic fields contributing to the predetermined magnetic field distribution generated by the kit,a magnetic field sensing element for sensing a magnetic field at a surface of the volume, andan adjustable bracket to which the magnetic field generating element and the magnetic field sensing element are fixedly attached,setting a distance between the between the magnetic field generating element and the magnetic field sensing element using the adjustable bracket for each sensor-source unit,measuring a magnetic field using the magnetic field sensing elements, andMewburn Ref: 00866986330controlling the magnetic field generating elements based on the measured magnetic field such that the magnetic field detected by respective magnetic field sensing elements is within a range of variation from the predetermined magnetic field distribution.

20. Method for generating a predetermined magnetic field distribution in a predetermined volume in relation to a device using sensor-source units,wherein each sensor-source unit includesa magnetic field generating element for generating a respective magnetic field in the volume, the respective magnetic fields contributing to the predetermined magnetic field distribution generated by the kit,a magnetic field sensing element for sensing a magnetic field at a surface of the volume, anda bracket to which the magnetic field generating element and the magnetic field sensing element are fixedly attached,wherein the method comprises the steps ofcalculating a distance between the magnetic field generating element and the magnetic field sensing element for each sensor-source unit at their respective locations,arranging the plurality of sensor-source units at their respective locations, wherein each sensorsource unit has a distance between the between the magnetic field generating element and the magnetic field sensing element based on the calculated distance,measuring a magnetic field using the magnetic field sensing elements, andcontrolling the magnetic field generating elements based on the measured magnetic field such that the magnetic field detected by respective magnetic field sensing elements is within a range of variation from the predetermined magnetic field distribution.

21. The method of claim 20, wherein the step of arranging the plurality of sensor-source units includes preparing the plurality of sensor-source units, wherein each sensor-source unit has a distance between the magnetic field generating element and the magnetic field sensing element that is equal to the calculated distance.

22. The method of claim 20, wherein the plurality of sensor-source units includes various types of sensor-source units,wherein each type of sensor-source units has a different fixed distance between the magnetic field generating element and the magnetic field sensing element, andMewburn Ref: 00866986331wherein the step of arranging the plurality of sensor-source units includes selecting the type of sensor-source units that has a distance between the magnetic field generating element and the magnetic field sensing element that is closest to the calculated distance.

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