Electron beam detection device and detection method

Abstract

The present invention provides an electron beam detection device, comprising: a Faraday cup having an opening; a porous carbon material layer disposed on the surface of the Faraday cup and suspended at the opening, the suspended length of the porous carbon material layer being greater than or equal to the maximum diameter of the electron beam to be measured; and an electric meter electrically connected to the porous carbon material layer, for measuring an electrical signal generated by charges in the porous carbon material layer during relative movement of the electron beam to be measured and the porous carbon material layer, and obtaining the size of the electron beam to be measured based on the change in the electrical signal as the distance of relative movement of the electron beam to be measured and the porous carbon material layer increases. The present invention also provides a detection method for detecting an electron beam using the above-mentioned electron beam detection device.

Description

Technical Field

[0001] The present invention relates to an electron beam detection device and a detection method, and in particular to an electron beam detection device and a detection method using a porous carbon material linear structure or strip structure. Background Art

[0002] Electrons are accelerated and their energy is increased by forces applied in an electric field. They converge into a beam in a vacuum, creating an electron beam. Electron beam technology has been widely applied in the forming, manufacturing, and refining of high-temperature alloys, as well as in welding, surface modification, and coating preparation. It is also increasingly finding applications in aerospace, defense, and nuclear industries. The shape and size of the electron beam directly influence its effectiveness in applications. Therefore, electron beam detection devices and methods are crucial.

[0003] Existing electron beam detection devices and methods using metal sheets simply differentiate the measured electrical curve to obtain the electron beam spot size. However, this method can cause the electron beam to scatter at the edges of the metal sheet, leading to inaccurate measurements. Therefore, providing an electron beam detection device and method that delivers accurate measurement results is of great significance. Summary of the Invention

[0004] In view of this, the present invention provides an electron beam detection device and a detection method with accurate measurement results.

[0005] An electron beam detection device, comprising:

[0006] a Faraday cup having an opening;

[0007] a porous carbon material layer, wherein the porous carbon material layer is a porous carbon material linear structure or a porous carbon material strip structure, the porous carbon material layer is disposed on the surface of the Faraday cup and suspended at the opening, the suspended length of the porous carbon material layer is greater than or equal to the maximum diameter of the electron beam to be measured, the diameter of the porous carbon material linear structure and the width of the porous carbon material strip structure are both less than the minimum diameter of the cross section of the electron beam to be measured, and the porous carbon material layer is composed of a plurality of carbon material particles, with nanometer-scale or micrometer-scale gaps between the plurality of carbon material particles; and

[0008] An electric meter is electrically connected to the porous carbon material layer.

[0009] An electron beam detection method comprises the following steps:

[0010] Step S1, providing an electron beam detection device according to any one of claims 1 to 7;

[0011] Step S2, moving the electron beam to be measured relative to the porous carbon material layer, so that the entire cross-section of the electron beam to be measured passes through the suspended portion of the porous carbon material layer, thereby achieving scanning of the porous carbon material layer by the electron beam to be measured, and during the movement, recording the distance moved by the electron beam to be measured or the porous carbon material layer and the electrical signal value in the ammeter to obtain a first curve, and obtaining a first diameter of the electron beam to be measured by analyzing the first curve; and

[0012] Step S3, rotate the electron beam to be measured or the porous carbon material layer by a certain angle, so that the electron beam to be measured moves relative to the porous carbon material layer, and the entire cross-section of the electron beam to be measured passes through the suspended part of the porous carbon material layer, thereby realizing the scanning of the porous carbon material layer by the electron beam to be measured, and in the process of movement, record the distance moved by the electron beam to be measured or the porous carbon material layer and the electrical signal value in the ammeter to obtain a second curve, and obtain the second diameter of the electron beam to be measured by analyzing the second curve.

[0013] Compared with the prior art, the electron beam detection device provided by the present invention adopts a porous carbon material layer suspended on a Faraday cup, and the porous carbon material layer includes a plurality of carbon material particles. There are nanometer-level or micrometer-level gaps between the plurality of carbon material particles. The electrons in the electron beam to be measured will be refracted and reflected multiple times in the gaps between the plurality of carbon material particles in the porous carbon material layer, and cannot be emitted from the porous carbon material layer. The absorption rate of the porous carbon material layer to electrons can reach more than 97%, almost 100%, and can be regarded as an absolute black body for electrons. Therefore, during detection, when the electron beam passes through the suspended portion of the porous carbon material layer and intersects the porous carbon material layer, all the electrons in the electron beam are absorbed by the porous carbon material layer, and various scatterings will not occur at the edge of the porous carbon material layer, reducing the detection accuracy. Therefore, the measurement results of the electron beam detection device and detection method provided by the present invention are more accurate. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a schematic structural diagram of an electron beam detection device provided in the first embodiment of the present invention.

[0015] Figure 2 This is a scanning electron microscope photograph of the non-twisted carbon nanotube wire provided by the first embodiment of the present invention.

[0016] Figure 3 This is a scanning electron microscope photograph of the twisted carbon nanotube wire provided by the first embodiment of the present invention.

[0017] Figure 4 The present invention adopts Figure 1 A scanning electron microscope photograph of the electron beam testing device when testing the electron beam.

[0018] Figure 5The present invention adopts Figure 1 A schematic top view of the movement of the electron beam to be tested relative to the carbon nanotube linear structure when the electron beam testing device is testing the electron beam.

[0019] Figure 6 To adopt Figure 1 When the electron beam testing device tests an electron beam, the electric meter measures a curve showing the change of current intensity with the moving distance of the electron beam to be tested.

[0020] Figure 7 This is a schematic structural diagram of an electron beam detection device provided by the second embodiment of the present invention.

[0021] Figure 8 This is a flow chart of an electron beam detection method provided by the second embodiment of the present invention.

[0022] Description of main component symbols

[0023]

[0024] The following specific embodiments will further illustrate the present invention in conjunction with the above-mentioned drawings. DETAILED DESCRIPTION

[0025] The electron beam detection device and detection method provided by the present invention will be described in detail below with reference to the accompanying drawings.

[0026] See also Figure 1 A first embodiment of the present invention provides an electron beam detection device 10. The electron beam detection device 10 includes a substrate 102, a porous carbon material layer 103, a Faraday cup 104, and an electric meter 105. One terminal of the electric meter 105 is electrically connected to the porous carbon material layer 103, and the other terminal is grounded.

[0027] The substrate 102 has a through hole 1021. The porous carbon material layer 103 is arranged on the surface of the substrate 102 and is suspended at the through hole 1031. The length of the suspended portion of the porous carbon material layer 103 is greater than or equal to the maximum diameter of the electron beam to be measured. The Faraday cup 104 has an opening 1041. The Faraday cup 104 is arranged below the substrate 102, and the opening 1041 is connected to the through hole 1021. The Faraday cup 104 is used to collect electrons that pass through the through hole 1031 and are not absorbed by the suspended porous carbon material layer 103, thereby preventing the electrons that are not absorbed by the suspended porous carbon material layer 103 from being reflected to generate secondary electrons that are again absorbed by the suspended porous carbon material layer 103, affecting the accuracy of electron beam detection.

[0028] The substrate 102 is preferably a flat structure. The material of the substrate 102 is an insulating material. Examples include glass, plastic, silicon wafer, silicon dioxide wafer, quartz wafer, polymethyl methacrylate (PMMA), polyethylene terephthalate (PET), silicon, silicon with an oxide layer, quartz, etc. The shape and size of the substrate 102 are designed according to actual needs. In this embodiment, the substrate 102 is a rectangular silicon substrate.

[0029] It is understood that the substrate 102 is an optional component and is not required. For example, in one embodiment, the electron beam detection device 10 does not include the substrate 102, and the porous carbon material layer 103 is directly disposed on the upper surface of the Faraday cup 104, and the porous carbon material layer 103 is suspended through the opening 1051 of the Faraday cup 105.

[0030] The porous carbon material layer 103 is a porous carbon material linear structure or a porous carbon material strip structure. When the porous carbon material layer 103 is a porous carbon material linear structure, the diameter of the porous carbon material linear structure is smaller than the minimum diameter of the cross section of the electron beam to be measured. Preferably, the diameter range of the carbon nanotube linear structure 103 is less than or equal to 20 microns. When the porous carbon material layer 103 is a porous carbon material strip structure, the width of the porous carbon material strip structure is less than the minimum diameter of the cross section of the electron beam to be measured. The diameter of the porous carbon material linear structure or the width of the porous carbon material strip structure is much smaller than the diameter of the cross section of the electron beam to be measured, and the smaller the diameter of the porous carbon material linear structure or the width of the porous carbon material strip structure, the higher the accuracy of the detection. Preferably, the width range of the porous carbon material strip structure is less than or equal to 20 microns.

[0031] The porous carbon material layer 103 is composed of a plurality of carbon material particles, and there are tiny gaps between the plurality of carbon material particles. The gaps between the plurality of carbon material particles are preferably nanometer-scale or micrometer-scale. The micrometer-scale refers to a size less than or equal to 1000 micrometers, and the nanometer-scale refers to a size less than or equal to 1000 nanometers. Furthermore, the micrometer-scale refers to a size less than or equal to 100 micrometers, and the nanometer-scale refers to a size less than or equal to 100 nanometers. The size of the gap is preferably 5 micrometers to 50 micrometers. More preferably, the size of the gap is 5 micrometers to 30 micrometers. The porous carbon material layer 103 is a self-supporting structure. The so-called "self-supporting" means that the porous carbon material layer 103 can maintain its own specific shape without being set on the surface of a substrate.

[0032] There are tiny gaps between the multiple carbon material particles in the porous carbon material layer 103. After the electron beam enters the porous carbon material layer 103, it will be refracted and reflected multiple times in the tiny gaps between the multiple carbon material particles in the porous carbon material layer 103, and cannot be emitted from the porous carbon material layer 103. The absorption rate of the porous carbon material layer 103 to electrons reaches more than 99.99%, and can almost reach 100%. In other words, the porous carbon material layer 103 can be regarded as an absolute black body for electrons. When the electron beam passes through the suspended portion in the porous carbon material layer 103 and the electron beam intersects the suspended portion of the porous carbon material layer 103, all the electrons in the electron beam are absorbed by the porous carbon material layer 103, and various scatterings will not occur at the edges in the porous carbon material layer 103, thereby reducing the detection accuracy.

[0033] The carbon material particles include one or both of linear particles and spherical particles. The maximum diameter of the cross section of the linear particles is less than or equal to 1000 microns. The linear particles may be carbon fibers, carbon microwires, carbon nanotubes, etc. The maximum diameter of the spherical particles is less than or equal to 1000 microns. The spherical particles may be carbon nanospheres or carbon microspheres, etc. Preferably, the carbon material particles are carbon nanotubes, and the porous carbon material layer 103 is a carbon nanotube linear structure or a carbon nanotube strip structure. The carbon nanotube linear structure or the carbon nanotube strip structure is preferably a pure carbon nanotube structure, which means that the carbon nanotube linear structure or the carbon nanotube strip structure only includes carbon nanotubes, does not contain other impurities, and the carbon nanotubes are also pure carbon nanotubes. In this embodiment, the porous carbon material layer 103 is a carbon nanotube linear structure.

[0034] The carbon nanotube linear structure may include one or more carbon nanotube wires. When multiple carbon nanotube wires are included, the multiple carbon nanotube wires may be twisted, stacked, or arranged in parallel on a coplanar surface. The carbon nanotube wires may be non-twisted carbon nanotube wires or twisted carbon nanotube wires.

[0035] See also Figure 2The non-twisted carbon nanotube wire comprises a plurality of carbon nanotubes aligned along the length of the non-twisted carbon nanotube wire. The non-twisted carbon nanotube wire can be obtained by treating a carbon nanotube film with an organic solvent. The so-called carbon nanotube film is a self-supporting carbon nanotube film obtained by directly drawing from a carbon nanotube array. Specifically, the carbon nanotube film comprises a plurality of carbon nanotube segments connected end-to-end by van der Waals forces. Each carbon nanotube segment comprises a plurality of parallel carbon nanotubes tightly bound by van der Waals forces. The carbon nanotube segments can have any length, thickness, uniformity, and shape. Specifically, the entire surface of the carbon nanotube film can be impregnated with an organic solvent. Under the action of surface tension generated by the evaporation of the volatile organic solvent, the parallel carbon nanotubes in the carbon nanotube film are tightly bound by van der Waals forces, thereby shrinking the carbon nanotube film into a non-twisted carbon nanotube wire. The organic solvent can be a volatile organic solvent such as ethanol, methanol, acetone, dichloroethane, or chloroform. Compared with the carbon nanotube film not treated with organic solvent, the non-twisted carbon nanotube wire treated with organic solvent has a smaller specific surface area and lower viscosity.

[0036] See also Figure 3 The twisted carbon nanotube wire is composed of a plurality of carbon nanotubes arranged substantially in parallel and twisted along the axial direction of the twisted carbon nanotube wire. The twisted carbon nanotube wire can be formed by relatively rotating the two ends of the non-twisted carbon nanotube wire. In the process of relatively rotating the two ends of the non-twisted carbon nanotube wire, the carbon nanotubes in the non-twisted carbon nanotube wire will be arranged in a spiral shape along the axial direction of the carbon nanotube wire, and connected end to end by van der Waals force in the extension direction, thereby forming the twisted carbon nanotube wire. The carbon nanotube single yarn is S-twisted or Z-twisted. In addition, in the process of relatively rotating the two ends of the non-twisted carbon nanotube wire, the spacing between the carbon nanotubes adjacent in the radial direction in the non-twisted carbon nanotube wire will become smaller, and the contact area will increase, thereby significantly increasing the van der Waals force between the carbon nanotubes adjacent in the radial direction in the twisted carbon nanotube wire, and closely connecting them.

[0037] The electric meter 104 is used to measure the charge generated in the porous carbon material layer 103 and convert the value into an electrical signal. The electric meter 104 can be an ammeter or a voltmeter. In this embodiment, the electric meter 104 is an ammeter, which is used to measure the current value generated by the charge in the porous carbon material layer 103.

[0038] When the electron beam detection device 10 is in use, the substrate 102, the porous carbon material layer 103, and the Faraday cup 104 are arranged in a vacuum chamber, and the vacuum chamber has an entrance, and the electron beam to be measured enters the vacuum chamber through the entrance. The electron beam to be measured is moved relative to the porous carbon material layer 103 to achieve the electron beam to be measured scanning the suspended part of the porous carbon material layer 103. The relative movement can be achieved by moving the electron beam to be measured, and can also be achieved by moving the porous carbon material layer 103. In this embodiment, the electron beam to be measured is moved so that the electron beam to be measured scans the suspended part of the porous carbon material layer 103. Preferably, the moving direction of the electron beam to be measured is perpendicular to the length direction of the porous carbon material layer 103. In the process of relative movement of the electron beam to be measured relative to the porous carbon material layer 103, the size of the electron beam hitting the porous carbon material layer 103 is changing, and therefore, the amount of charge generated by the porous carbon material layer 103 is also changing. According to the curve of the change of the electrical signal in the ammeter 104 as the distance of movement of the electron beam to be measured, a diameter of the electron beam to be measured can be obtained. By moving the electron beam to be measured perpendicular to the length direction of the porous carbon material layer 103 along a plurality of different diameter directions, a plurality of diameters of the electron beam to be measured can be obtained, and the average value of the plurality of diameters can be taken to obtain the size of the electron beam to be measured. In this embodiment, two diameters in the horizontal direction and the vertical direction are tested respectively. Preferably, when the electron beam to be measured moves relative to the porous carbon material layer 103, the electron beam to be measured hits the suspended portion of the porous carbon material layer 103, and no electron beam hits the two ends of the porous carbon material layer 103 in direct contact with the substrate 102.

[0039] After the electron beam to be measured moves perpendicularly to the length direction of the porous carbon material layer 103 along one diameter direction, the electron beam to be measured can be moved perpendicularly to the length direction of the porous carbon material layer 103 along another diameter direction by rotating the electron beam to be measured or rotating the porous carbon material layer 103. In other words, the electron beam to be measured can be moved perpendicularly to the length direction of the porous carbon material layer 103 along multiple diameter directions by rotating the electron beam to be measured or rotating the porous carbon material layer 103. In this embodiment, the porous carbon material layer 103 is provided on the substrate 102, and the direction of the porous carbon material layer 103 is changed by rotating the substrate 102. Please refer to Figure 4 , is a scanning electron microscope photo of the electron beam test device 10 used in this embodiment to test the electron beam, wherein, Figure 4 a is an electron microscope photograph of the electron beam being moved perpendicularly to the length of the carbon nanotube linear structure while maintaining the first diameter of the electron beam being parallel to the length of the carbon nanotube linear structure; and then the carbon nanotube linear structure is rotated 90 degrees. Figure 4b is an electron microscope photograph of the electron beam being moved perpendicular to the length direction of the carbon nanotube linear structure while keeping the second diameter of the electron beam parallel to the length direction of the carbon nanotube linear structure.

[0040] See also Figure 5 In the process of the electron beam to be measured moving relative to the carbon nanotube linear structure, the electron beam to be measured does not hit the suspended carbon nanotube linear structure at the beginning. At this time, no charge is generated in the carbon nanotube linear structure, and the electrical signal measured in the ammeter 104 is basically zero; the electron beam to be measured continues to move, and a small amount of electron beams will hit the suspended carbon nanotube linear structure. At this time, a small amount of charge is generated in the carbon nanotube linear structure, and as the movement proceeds, the number of electron beams hitting the suspended carbon nanotube linear structure increases, and the charge generated in the carbon nanotube linear structure increases, until the maximum diameter of the electron beam to be measured in the direction perpendicular to the moving direction coincides with the suspended carbon nanotube linear structure, the charge generated in the carbon nanotube linear structure reaches a maximum, and at this time, the electrical signal value measured in the ammeter 104 is also the maximum; as the movement continues, the charge generated in the carbon nanotube linear structure gradually decreases, and the electrical signal value measured in the ammeter 104 also gradually decreases. Therefore, the distance from the point where the current value starts to increase from zero to the point where the current value drops to zero again is the length of one diameter of the electron beam to be measured.

[0041] See also Figure 6 , shows a curve showing the variation of current intensity as measured by the ammeter with the travel distance of the electron beam under test when the electron beam testing device 10 is used to test an electron beam in this embodiment. As can be seen from the figure, the diameter of the electron beam in both directions is essentially the same, approximately 420 microns. The figure also shows that the curve showing the variation of current intensity as measured by the electron beam testing device 10 with the travel distance of the electron beam under test is substantially consistent with a standard curve showing the variation of current intensity with the travel distance of the electron beam under test, demonstrating the high detection accuracy of the electron beam testing device 10.

[0042] The porous carbon material layer in the electron beam testing device 10 provided by the present invention includes a plurality of carbon material particles, and there is a nanometer-level or micrometer-level gap between the plurality of carbon material particles. The electrons in the electron beam to be measured will be refracted and reflected multiple times in the gaps between the plurality of carbon material particles in the porous carbon material layer, and cannot be emitted from the porous carbon material layer. At this time, the absorptivity of the porous carbon material layer to electrons can reach more than 99.99%, almost 100%, and can be regarded as an absolute black body of electrons. When there is an electron beam to be measured that irradiates the suspended portion of the porous carbon material layer, the electrons irradiated on the porous carbon material layer are substantially all collected by the porous carbon material layer, and various scatterings will not occur at the edge of the porous carbon material layer, reducing the detection accuracy. Therefore, the method measures the multiple diameters of the electron beam to be measured more accurately, thereby making the accuracy of the electron beam detection device higher. The Faraday cup is used to collect electrons from the electron beam that pass through the through-hole and do not intersect the suspended porous carbon material layer. This prevents electrons not collected by the suspended carbon nanotube linear structure from being reflected and generating secondary electrons that are again collected by the suspended porous carbon material layer, thereby affecting the accuracy of electron beam detection. Furthermore, the electron beam detection device provided by the present invention utilizes a porous carbon material layer, and the size of the electron beam can be determined by the relative motion between the electron beam to be measured and the porous carbon material layer. The structure of the electron beam detection device is very simple.

[0043] See also Figure 7 The second embodiment of the present invention provides an electron beam detection device 20. This electron beam detection device 20 is substantially identical to the electron beam detection device 10 of the first embodiment, differing only in that the porous carbon material layer 203 of this embodiment is a carbon nanotube strip structure. In other words, this embodiment uses a carbon nanotube strip structure instead of the carbon nanotube linear structure of the first embodiment.

[0044] The carbon nanotube strip structure may include a strip of porous carbon nanofilm or a plurality of strips of carbon nanotube films stacked together, as long as the width of the strip of carbon nanotube film is less than the minimum diameter of the cross section of the electron beam to be measured. The strip of carbon nanotube film may be a carbon nanotube drawn film, a carbon nanotube flocculent film, or a carbon nanotube rolled film. The carbon nanotube strip structure may also include a strip of carbon nanotube paper or a plurality of strips of carbon nanotube paper stacked together, as long as the width of the strip of carbon nanotube film is less than the minimum diameter of the cross section of the electron beam to be measured. The width of the carbon nanotube strip structure 203 is much smaller than the diameter of the electron beam to be measured, and the smaller the width of the carbon nanotube strip structure, the higher the accuracy of the detection. Preferably, the width range of the carbon nanotube strip structure is less than or equal to 20 microns. The length of the suspended part of the carbon nanotube strip structure is greater than or equal to the maximum diameter of the electron beam to be measured. The carbon nanotube strip structure can also be a carbon nanotube network structure or a carbon nanotube array, as long as the width of the carbon nanotube network structure or carbon nanotube array is less than the minimum diameter of the cross section of the electron beam to be measured. In this embodiment, the carbon nanotube strip structure is composed of a plurality of stacked carbon nanotube films.

[0045] The carbon nanotube film comprises a plurality of carbon nanotubes arranged substantially parallel to each other and substantially parallel to the surface of the carbon nanotube film. Specifically, the carbon nanotube film comprises a plurality of carbon nanotubes connected end-to-end by van der Waals forces and preferentially oriented substantially in the same direction. The carbon nanotube film can be obtained by directly drawing from a carbon nanotube array and is a self-supporting structure. Because the numerous carbon nanotubes in the self-supporting carbon nanotube film are mutually attracted by van der Waals forces, the carbon nanotube film has a specific shape, forming a self-supporting structure. The thickness of the carbon nanotube film ranges from 0.5 nanometers to 100 microns, and the width is related to the size of the carbon nanotube array from which the film is drawn, but the length is not limited. The structure and preparation method of the carbon nanotube film are described in Chinese Published Patent Application No. CN101239712A, filed by Fan Shoushan et al. on February 9, 2007, and published on August 13, 2008. To save space, this is only cited here, but all technical disclosures of the aforementioned application should also be considered part of the technical disclosures of the present application. The majority of carbon nanotubes in the carbon nanotube drawn film are connected end-to-end by van der Waals forces. In one embodiment, the carbon nanotube film structure is formed by stacking and intersecting multiple layers of carbon nanotube drawn films. The carbon nanotubes in adjacent carbon nanotube drawn films have a crossing angle α, and the crossing angle α is greater than 0 degrees and less than or equal to 90 degrees. The carbon nanotubes in the multiple carbon nanotube drawn films are interwoven to form a network-like film structure.

[0046] The carbon nanotube flocculated membrane comprises a plurality of carbon nanotubes that are entangled and evenly distributed. The carbon nanotubes are attracted and entangled with each other through van der Waals forces, forming a network structure, thereby forming a self-supporting carbon nanotube flocculated membrane. The carbon nanotube flocculated membrane is isotropic. The carbon nanotube flocculated membrane can be obtained by flocculating a carbon nanotube array. For the structure and preparation method of the carbon nanotube flocculated membrane, please refer to Chinese Published Patent Application No. CN101284662A, filed by Fan Shoushan et al. on April 13, 2007, and published on October 15, 2008. To save space, this disclosure is cited only herein, but all technical disclosures of the aforementioned application should also be considered part of the technical disclosures of the present application.

[0047] The carbon nanotube rolled film includes a plurality of carbon nanotubes arranged in a disordered manner, preferentially oriented in one direction, or preferentially oriented in multiple directions, with adjacent carbon nanotubes bonded by van der Waals forces. The carbon nanotube rolled film can be obtained by using a flat press head to press the carbon nanotube array in a direction perpendicular to the substrate on which the carbon nanotube array grows. In this case, the carbon nanotubes in the carbon nanotube rolled film are arranged in a disordered manner, and the carbon nanotube rolled film is isotropic. The carbon nanotube rolled film can also be obtained by using a roller-shaped press head to roll the carbon nanotube array in a fixed direction. In this case, the carbon nanotubes in the carbon nanotube rolled film are preferentially oriented in the fixed direction. The carbon nanotube rolled film can also be obtained by using a roller-shaped press head to roll the carbon nanotube array in different directions. In this case, the carbon nanotubes in the carbon nanotube rolled film are preferentially oriented in different directions. The structure and preparation method of the carbon nanotube rolled film are described in Chinese Published Patent Application No. CN101314464A, filed by Fan Shoushan et al. on June 1, 2007, and published on December 3, 2008. To save space, this application is cited here only, but all technical disclosures in the aforementioned application should be considered part of the technical disclosures of the present application.

[0048] The carbon nanotube paper comprises a plurality of carbon nanotubes extending and aligned substantially in the same direction. The carbon nanotubes are connected end-to-end along their extension direction by van der Waals forces, and are arranged substantially parallel to the surface of the carbon nanotube paper. The structure and preparation method of the carbon nanotube paper are described in Chinese Patent Publication No. CN103172044B, filed by Fan Shoushan et al. on December 21, 2011, and published on July 1, 2015. To conserve space, this disclosure is cited only here, but all technical disclosures in the aforementioned application should be considered part of the technical disclosures of the present application.

[0049] Said carbon nanotube array is preferably super-ordered carbon nanotube array, and the extending direction of carbon nanotube in this super-ordered carbon nanotube array is basically the same.The carbon nanotubes in this super-ordered carbon nanotube array closely contact and form array by van der Waals force each other.The size, thickness and surperficial area of ​​this super-ordered carbon nanotube array are not limit, and are limited according to actual needs.The preparation method of said super-ordered carbon nanotube array has been open for numerous previous cases, for example can consult people such as Feng Chen at disclosed Chinese patent application CN101239712A on August 13, 2008.Certainly, said carbon nanotube array is not limited to said super-ordered carbon nanotube array, also can be other carbon nanotube array.

[0050] Since the higher the energy of the electron beam, the deeper its penetration depth in the carbon nanotube strip structure, and vice versa, the penetration depth is shallower. For an electron beam with an energy less than or equal to 20 keV, preferably, the thickness of the carbon nanotube strip structure ranges from 200 microns to 600 microns. Within this thickness range, the electron beam is not easy to penetrate the carbon nanotube strip structure, nor is it easy to be reflected from the carbon nanotube strip structure. Within this range, the carbon nanotube strip structure has a relatively high absorption rate for electrons. More preferably, the thickness of the carbon nanotube strip structure is 300-500 microns. More preferably, the thickness of the carbon nanotube strip structure is 250-400 microns.

[0051] Except for using a carbon nanotube strip structure to replace the carbon nanotube linear structure in the first embodiment, the other technical features of this embodiment are the same as those of the first embodiment, and are not described here for the sake of space.

[0052] It is understood that the porous nanomaterial strip structure is not limited to the carbon nanotube strip structure in this embodiment, and can also be a self-supporting porous nanomaterial strip structure formed by carbon fibers, carbon nanospheres or carbon nanowires.

[0053] See also Figure 8 The second embodiment of the present invention further provides a method for detecting an electron beam using the electron beam detection device 10. The detection method specifically includes the following steps:

[0054] Step S1, providing the electron beam detection device 10 or 20;

[0055] Step S2, moving the electron beam to be measured relative to the porous carbon material layer 103 or 203, so that the entire cross-section of the electron beam to be measured passes through the suspended portion of the porous carbon material layer 103 or 203, thereby achieving scanning of the suspended portion of the porous carbon material layer 103 or 203 by the electron beam to be measured, and during the movement, recording the distance moved by the electron beam to be measured or the porous carbon material layer 103 or 203 and the electrical signal value in the ammeter to obtain a first curve, and obtaining a first diameter of the electron beam to be measured by analyzing the first curve; and

[0056] Step S3, rotate the electron beam to be measured or the porous carbon material layer 103 or 203 by a certain angle, so that the electron beam to be measured moves relative to the porous carbon material layer 103 or 203, and the entire cross-section of the electron beam to be measured passes through the suspended part of the porous carbon material layer 103 or 203, thereby realizing the scanning of the suspended part of the porous carbon material layer 103 or 203 by the electron beam to be measured, and in the process of moving, record the distance moved by the electron beam to be measured or the porous carbon material layer 103 or 203 and the electrical signal value in the ammeter to obtain a second curve, and obtain the second diameter of the electron beam to be measured by analyzing the second curve.

[0057] In step S1, the electron beam detection device 10 is the electron beam detection device 10 in the first embodiment, which includes all the technical features of the electron beam detection device 10 in the first embodiment. The electron beam detection device 20 is the electron beam detection device 20 in the second embodiment, which includes all the technical features of the electron beam detection device 20 in the second embodiment, which are not repeated here.

[0058] In step S2, the electron beam to be measured preferably moves in a direction perpendicular to the length of the porous carbon material layer relative to the porous carbon material layer 103 or 203. Preferably, when the electron beam to be measured moves relative to the porous carbon material layer 103 or 203, the electron beam to be measured hits the suspended portion of the porous carbon material layer 103 or 203, and no electron beam hits the ends of the porous carbon material layer 103 that are in direct contact with the substrate 102.

[0059] According to the distance moved by the electron beam to be measured or the porous carbon material layer 103 or 203 and the electrical signal value in the ammeter, a curve of the distance moved by the electron beam to be measured or the porous carbon material layer and the electrical signal value is obtained. The distance from the point where the electrical signal value starts to increase from zero to the point where the current value drops to zero again in the changing curve is the length of the first diameter of the electron beam to be measured.

[0060] In step S3, the electron beam or the porous carbon material layer to be measured is rotated at an angle greater than 0 degrees and less than 180 degrees. In this embodiment, the porous carbon material layer is rotated at an angle of 90 degrees. Since the porous carbon material layer 103 or 203 is disposed on the substrate 102, the direction of the porous carbon material layer 103 or 203 can be changed by rotating the substrate 102.

[0061] After rotating the electron beam or the carbon nanotube linear structure by a certain angle, the electron beam preferably moves relative to the porous carbon material layer in a direction perpendicular to the length of the porous carbon material layer. Preferably, when the electron beam moves relative to the porous carbon material layer 103 or 203, the electron beam strikes the suspended portion of the porous carbon material layer 103 or 203, and no electron beam strikes the ends of the porous carbon material layer 103 or 203 that are in direct contact with the substrate 102.

[0062] After the electron beam or carbon nanotube linear structure to be measured rotates a certain angle, a change curve of the distance moved by the electron beam or porous carbon material layer to be measured and the electrical signal value is obtained according to the distance moved by the electron beam or porous carbon material layer to be measured and the electrical signal value in the ammeter. The distance from the point where the electrical signal value starts to increase from zero to the point where the current value drops to zero again in the change curve is the length of the second diameter of the electron beam to be measured.

[0063] During the electron beam detection method, the porous carbon material layer 103, substrate 102 and Faraday cup 104 in the electron beam detection device 10 are placed in a vacuum chamber, and the electron beam to be detected is projected into the vacuum chamber for detection.

[0064] It can be understood that in some embodiments, in order to increase the accuracy of the electron beam detection method, step S3 is further repeated multiple times after step S3 to obtain multiple diameters of the electron beam to be measured.

[0065] The electron beam detection device provided by the present invention adopts a porous carbon material layer, and the size of the electron beam can be obtained by the relative motion between the electron beam to be measured and the porous carbon material layer, and the electron beam detection method is very simple. The electron beam detection method provided by the present invention can obtain multiple diameters of the electron beam to be measured by the electron beam to be measured and the porous carbon material layer performing multiple relative motions, and then obtain the size of the electron beam to be measured, so the accuracy is relatively high. Moreover, the porous carbon material layer includes a plurality of carbon material particles, and there are nanometer-level or micrometer-level gaps between the plurality of carbon material particles. The electrons in the electron beam to be measured will be refracted and reflected multiple times in the gaps between the plurality of carbon material particles in the porous carbon material layer, and cannot be emitted from the porous carbon material layer. At this time, the absorption rate of the porous carbon material layer to electrons can reach more than 99.99%, and can almost reach 100%, which can be regarded as an absolute black body for electrons. When the electron beam to be measured is irradiated onto the porous carbon material layer, the electrons irradiated onto the porous carbon material layer are basically all absorbed by the carbon nanotube linear structure, and various scattering will not occur at the edge of the carbon nanotube linear structure, thereby reducing the detection accuracy. Therefore, the method measures the multiple diameters of the electron beam to be measured more accurately, thereby making the accuracy of the electron beam detection device higher. Moreover, during the detection process, the Faraday cup can collect electrons in the electron beam that passes through the through hole and does not intersect with the suspended porous carbon material layer, thereby avoiding the electrons that are not collected by the suspended porous carbon material layer from being reflected to generate secondary electrons that are again collected by the suspended porous carbon material layer, thereby improving the accuracy of the electron beam detection method.

[0066] In addition, those skilled in the art may also make other changes within the spirit of the present invention. Of course, these changes made according to the spirit of the present invention should be included in the scope of protection required by the present invention.

Claims

1. An electron beam detection device, comprising: a Faraday cup having an opening; a porous carbon material layer, wherein the porous carbon material layer is a porous carbon material linear structure or a porous carbon material strip structure, the porous carbon material layer is disposed on the surface of the Faraday cup and is suspended at the opening, the suspended length of the porous carbon material layer is greater than or equal to the maximum diameter of the electron beam to be measured, the diameter of the porous carbon material linear structure and the width of the porous carbon material strip structure are both less than the minimum diameter of the cross section of the electron beam to be measured, and the porous carbon material layer is composed of a plurality of carbon material particles, and nanometer-scale or micrometer-scale gaps exist between the plurality of carbon material particles; as well as An electric meter is electrically connected to the porous carbon material layer.

2. The electron beam detection device according to claim 1, wherein The carbon material particles are one or more of carbon nanotubes, carbon fibers, carbon nanowires, carbon microspheres or carbon nanospheres.

3. The electron beam detection device according to claim 1, wherein The porous carbon material linear structure is a carbon nanotube linear structure, which includes one or more carbon nanotube wires, and the carbon nanotube wires are non-twisted carbon nanotube wires or twisted carbon nanotube wires.

4. The electron beam detection device according to claim 1, wherein The porous carbon material strip structure is a carbon nanotube strip structure, which includes a strip of carbon nanotube film or a plurality of strips of carbon nanotube film stacked together; a strip of carbon nanotube paper or a plurality of strips of carbon nanotube paper stacked together; a carbon nanotube network structure; or a carbon nanotube array.

5. The electron beam detection device according to claim 1, wherein The diameter of the porous carbon material linear structure is less than or equal to 20 microns.

6. The electron beam detection device according to claim 1, wherein The electron beam detection device further includes a substrate having a through hole. The substrate is arranged between the Faraday cup and the porous carbon material layer, and the through hole is connected to the opening of the Faraday cup. The porous carbon material layer is arranged on the surface of the substrate and is suspended at the through hole of the substrate.

7. An electron beam detection method comprising the following steps: Step S1, providing an electron beam detection device according to any one of claims 1 to 6; Step S2, moving the electron beam to be measured relative to the porous carbon material layer, so that the entire cross-section of the electron beam to be measured passes through the suspended portion of the porous carbon material layer, thereby achieving the electron beam to be measured scanning the suspended portion of the porous carbon material layer, and during the movement, recording the distance moved by the electron beam to be measured or the porous carbon material layer and the electrical signal value in the ammeter to obtain a first curve, and obtaining a first diameter of the electron beam to be measured by analyzing the first curve; as well as Step S3, rotate the electron beam to be measured or the porous carbon material layer by a certain angle, so that the electron beam to be measured moves relative to the porous carbon material layer, and the entire cross-section of the electron beam to be measured passes through the suspended part of the porous carbon material layer, thereby realizing the electron beam to be measured scanning the suspended part of the porous carbon material layer, and in the process of moving, record the distance moved by the electron beam to be measured or the porous carbon material layer and the electrical signal value in the ammeter to obtain a second curve, and obtain the second diameter of the electron beam to be measured by analyzing the second curve.

8. The electron beam detection method according to claim 7, wherein: After step S3, the method further includes repeating step S3 multiple times to obtain multiple diameters of the electron beam to be measured.

9. The electron beam detection method according to claim 7, wherein: In step S2, a curve of the distance moved by the electron beam or porous carbon material layer to be measured and the value of the electrical signal is obtained according to the distance moved by the electron beam or porous carbon material layer to be measured and the value of the electrical signal in the ammeter. The distance from the point where the electrical signal value starts to increase from zero to the point where the current value drops to zero again in the change curve is the length of the first diameter of the electron beam to be measured.

10. The electron beam detection method according to claim 7, wherein: In steps S2 and S3, the electron beam to be measured moves vertically relative to the length direction of the porous carbon material layer.

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