A gain-free microchannel plate two-dimensional framing imaging system

Abstract

The present application relates to a kind of gainless microchannel plate two-dimensional framing imaging system.The system includes vacuum drift tube, long-short magnetic combination lens, gainless electron beam time amplifier, gated microchannel plate detector and pulse generator, long-short magnetic combination lens is surrounded outside vacuum drift tube, gainless electron beam time amplifier is located at the incident end of vacuum drift tube, gated microchannel plate detector is located at the exit end of vacuum drift tube, the region between the incident end and the exit end in vacuum drift tube is electron drift region.The present application uses electron beam time amplification technology to improve the time resolution of framing imaging camera, and uses gainless microchannel plate electron beam time amplifier to improve the uniformity of time resolution and gain uniformity, and uses long-short magnetic combination lens to improve spatial resolution and its uniformity, and uses two-way broadening pulse transmission mode to increase effective picture size, so as to improve the performance indicators of framing imaging camera.

Description

Technical Field

[0001] This invention relates to the field of ultrafast diagnostic technology, and more specifically, to a gain-free microchannel plate two-dimensional framing imaging system. Background Technology

[0002] Ultrafast diagnostic technology is mainly used in basic frontier science and large-scale scientific projects, and is an important and unique two-dimensional ultrafast diagnostic device. For example, it is used in laser inertial confinement fusion (ICF) research to detect X-ray radiation processes of 1-2 ns. X-ray framing imaging cameras can obtain the two-dimensional spatial distribution and temporal characteristics of X-ray radiation from ICF plasma, and improving the temporal resolution is a continuous pursuit in the industry. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a gain-free microchannel plate two-dimensional framing imaging system.

[0004] The technical solution adopted by this invention to solve its technical problem is as follows: a gain-free microchannel plate two-dimensional framing imaging system is constructed, including a vacuum drift tube, a long and short magnetic combination lens, a gain-free electron beam time amplifier, a gated microchannel plate detector, and a pulse generator. The long and short magnetic combination lens surrounds the outside of the vacuum drift tube, the gain-free electron beam time amplifier is located at the incident end of the vacuum drift tube, the gated microchannel plate detector is located at the exit end of the vacuum drift tube, and the region between the incident end and the exit end inside the vacuum drift tube is the electron drift region.

[0005] The gain-free electron beam time amplifier includes a microstrip cathode, a gain-free microchannel plate, and a grounded anode. The gain-free microchannel plate includes a first input surface, a first output surface, and multiple gain-free channels. The first input surface and the first output surface of the gain-free microchannel plate are parallel, and the gain-free channels penetrate the gain-free microchannel plate. The microstrip cathode is deposited on the first input surface of the gain-free microchannel plate, and the grounded anode is deposited on the entire first output surface of the gain-free microchannel plate. A negative DC voltage and a broadened pulse generated by the pulse generator are superimposed on the microstrip cathode, and two broadened pulses are transmitted simultaneously from both ends of the microstrip cathode, with the two broadened pulses having the same waveform. The grounded anode is grounded.

[0006] The gated microchannel plate detector includes an impedance gradient line, a microstrip line, a gain microchannel plate, a fluorescent screen, and a CCD camera. The gain microchannel plate includes a second input surface, a second output surface, and multiple gain channels, which penetrate the gain microchannel plate. The microstrip line is deposited in a strip shape on the second input surface of the gain microchannel plate, and a preset metal layer is deposited on the entire second output surface of the gain microchannel plate. The pulse generator is connected to the microstrip line through the impedance gradient line, and the pulse generator samples and multiplies the electron beam on the microstrip line through a gated pulse. The first surface of the fluorescent screen is parallel to and spaced apart from the second output surface of the gain microchannel plate, and the second surface of the fluorescent screen is in close contact with the CCD camera.

[0007] Furthermore, in the gain-free microchannel plate two-dimensional framing imaging system of the present invention, the outer diameter of the gain-free microchannel plate is 106 mm and the thickness is 1 mm; the diameter of the gain-free channel is 35 μm, the channel chamfer angle ranges from 6° to 8°, and the spacing between adjacent gain-free channels is 39 μm.

[0008] Three microstrip cathodes are deposited on the first input surface of the gain-free microchannel plate. Each microstrip cathode has a width of 12 mm and the spacing between adjacent microstrip cathodes is 10 mm.

[0009] Furthermore, in the gain-free microchannel plate two-dimensional framing imaging system of the present invention, the outer diameter of the gain microchannel plate is 106 mm and the thickness is 0.5 mm; the channel diameter of each gain channel is 12 μm, the channel chamfer angle ranges from 6° to 8°, and the spacing between adjacent gain channels is 14 μm;

[0010] Three microstrip lines are deposited on the second input surface of the gain microchannel board. Each microstrip line is 12mm wide and the spacing between adjacent microstrip lines is 10mm.

[0011] Furthermore, in the gain-free microchannel plate two-dimensional framing imaging system of the present invention, copper and gold layers of a preset depth are deposited into the input and output ports of each gain channel, with the copper layer located at the bottom layer and the gold layer located at the surface layer.

[0012] Furthermore, in the gain-free microchannel plate two-dimensional framing imaging system of the present invention, the microstrip cathode of the gain-free microchannel plate includes a copper layer at the bottom and a gold layer at the surface.

[0013] The ground anode of the gain-free microchannel plate includes a copper layer at the bottom and a gold layer at the top.

[0014] The microstrip line of the gated microchannel plate detector includes a copper layer at the bottom and a gold layer at the top.

[0015] The pre-deposited metal layer on the entire second output surface of the gain microchannel plate includes a copper layer at the bottom and a gold layer at the top.

[0016] Furthermore, in the gain-free microchannel plate two-dimensional framing imaging system of the present invention, the thickness of the copper layer is 500 nm and the thickness of the gold layer is 100 nm.

[0017] Furthermore, in the gain-free microchannel plate two-dimensional framing imaging system of the present invention, the long and short magnetic combination lens includes a long magnetic lens, a first short magnetic lens and a second short magnetic lens. The first short magnetic lens surrounds the incident end of the vacuum drift tube, the second short magnetic lens surrounds the exit end of the vacuum drift tube, and the long magnetic lens surrounds between the incident end and the exit end of the vacuum drift tube.

[0018] Furthermore, in the gain-free microchannel plate two-dimensional framing imaging system of the present invention, the first short magnetic lens is composed of a ring-shaped soft iron and a copper coil, the copper coil being located inside the soft iron, and the inner side of the first short magnetic lens having a slit with a width of 4mm; the outer diameter of the first short magnetic lens is 410mm, the inner diameter is 360mm, and the axial length is 100mm.

[0019] The second short magnetic lens is composed of a ring-shaped soft iron and a copper coil. The copper coil is located inside the soft iron. There is a 4mm wide slit on the inner side of the second short magnetic lens. The outer diameter of the second short magnetic lens is 410mm, the inner diameter is 360mm, and the length in the axial direction is 100mm.

[0020] Furthermore, in the gain-free microchannel plate two-dimensional framing imaging system of the present invention, the long magnetic lens is composed of copper enameled wire wound between the incident end and the exit end of the vacuum drift tube.

[0021] Furthermore, the gainless microchannel plate two-dimensional framing imaging system of the present invention also includes an imaging pinhole array located on the input side of the gainless electron beam time amplifier. The captured X-ray image is then processed by the imaging pinhole array to generate photoelectron images at different positions on the microstrip cathode.

[0022] The present invention provides a gainless microchannel plate two-dimensional framing imaging system with the following advantages: The present invention uses electron beam time magnification technology to improve the temporal resolution of the framing imaging camera, uses a gainless microchannel plate electron beam time amplifier to improve the uniformity of temporal resolution and gain, uses a combination of long and short magnetic lenses to improve spatial resolution and its uniformity, and uses a two-way stretching pulse counter-transmission method to increase the effective image size, thereby improving the various performance indicators of the framing imaging camera. Attached Figure Description

[0023] The present invention will be further described below with reference to the accompanying drawings and embodiments. In the accompanying drawings:

[0024] Figure 1 This is a schematic diagram of the structure of the gain-free microchannel plate two-dimensional framing imaging system provided in an embodiment of the present invention;

[0025] Figure 2a This is a schematic diagram of the structure of the gain-free microchannel plate provided in an embodiment of the present invention;

[0026] Figure 2b This is a schematic diagram of the structure of a gain-free channel provided in an embodiment of the present invention;

[0027] Figure 3 This is a schematic diagram of the gated pulse transmission and gating of the gated microchannel plate detector provided in an embodiment of the present invention;

[0028] Figure 4 This is a schematic diagram of the structure of the first short magnetic lens and the second short magnetic lens provided in an embodiment of the present invention;

[0029] Figure 5 This is a schematic diagram of the structure of the long magnetic lens provided in an embodiment of the present invention;

[0030] Figure 6a This is a schematic diagram of single-path stretched pulse unidirectional transmission of a microstrip cathode provided in an embodiment of the present invention;

[0031] Figure 6b This is a schematic diagram of the simultaneous opposite transmission of two broadened pulses from a microstrip cathode according to an embodiment of the present invention. Detailed Implementation

[0032] To provide a clearer understanding of the technical features, objectives, and effects of the present invention, specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0033] The ICF fusion combustion stage requires a camera temporal resolution better than 30 ps, ​​while current practical cameras have a temporal resolution of 60-100 ps. To improve temporal resolution, a gain-free microchannel plate two-dimensional framing imaging system is proposed, combining electron beam temporal amplification technology with microchannel plate (MCP) gated framing imaging technology. The electron beam temporal amplification system broadens the temporal width of the electron beam, achieving temporal amplification. Then, a gated microchannel plate detector is used to measure the broadened electron beam, thereby improving temporal resolution. Theoretical studies show that electron beam temporal amplification technology can improve camera temporal resolution to within 10 ps.

[0034] High-precision time-magnification ultrafast two-dimensional framing imaging technology was proposed in response to the urgent needs of ICF research. It can improve temporal resolution and enable framing imaging cameras to meet engineering and precision requirements, thus addressing the needs of ICF research and possessing significant scientific and application value. Furthermore, electron beam time-magnification technology also has application value in ultrafast X-ray diodes and picosecond CMOS.

[0035] refer to Figures 1 to 6b This embodiment will be described in detail below.

[0036] refer to Figure 1 This embodiment provides a gain-free microchannel plate two-dimensional framing imaging system. The system includes a vacuum drift tube 10, a long-short magnetic combination lens 20, a gain-free electron beam time amplifier 30, a gated microchannel plate detector 40, and a pulse generator 50. The vacuum drift tube 10 is a closed vacuum tube, preferably a cylindrical vacuum tube in this embodiment. The long-short magnetic combination lens 20 surrounds the outside of the vacuum drift tube 10 to generate the required magnetic field. The gain-free electron beam time amplifier 30 is located at the incident end of the vacuum drift tube 10, and the gated microchannel plate detector 40 is located at the exit end of the vacuum drift tube 10. The region between the incident and exit ends within the vacuum drift tube 10 is the electron drift region. It can be understood that both the gain-free electron beam time amplifier 30 and the gated microchannel plate detector 40 are located on the longitudinal axis of the vacuum drift tube 10 to facilitate electron propagation and detection.

[0037] refer to Figure 1 As shown in Figure 2, the gainless electron beam time amplifier 30 includes a microstrip cathode 301, a gainless microchannel plate 302, and a grounded anode 303. The microstrip cathode 301 serves two purposes: first, it converts incident light into photoelectrons; second, it transmits a broadened pulse, creating a time-varying electric field between the microstrip cathode and the anode to achieve electron beam time amplification. Existing electron beam time amplifiers consist of a microstrip cathode and an anode grid. A gold layer is deposited on polyimide to form a transmission-type microstrip cathode. Due to the need to balance quantum efficiency, the gold layer thickness is relatively small, approximately 80 nm. The thin microstrip cathode causes significant attenuation of the broadened pulse, resulting in a gradually decreasing pulse slope and inconsistent electron beam time amplification at different positions on the microstrip cathode, leading to poor time resolution and gain uniformity. Furthermore, the polyimide and grid thicknesses are only tens of micrometers. When fabricating large planar surfaces, their poor flatness hinders the application of high voltages between the cathode and grid. High voltages between the cathode and grid can improve spatial resolution, reduce electron transit time dispersion, and improve the limiting time resolution.

[0038] To address the problems in the prior art, this embodiment uses a gain-free microchannel plate 302 instead of polyimide and a grid in the prior art to fabricate an electron beam time amplifier. A reflective cathode structure is used to increase the thickness of the microstrip cathode conductive layer, reducing attenuation of the broadened pulse while maintaining high quantum efficiency. Furthermore, the two end faces of the gain-free microchannel plate 302 are very flat, allowing for the application of higher voltages. Therefore, this structure can simultaneously achieve high quantum efficiency, high anode-cathode voltage, high time resolution uniformity, and gain uniformity. The gain-free microchannel plate 302 is a semi-finished product of a gain microchannel plate, which becomes a gain microchannel plate after hydrogen reduction treatment. Before hydrogen reduction treatment, the channel walls of the gain-free microchannel plate 302 do not have a secondary electron emission layer, as shown in the schematic diagram below. Figure 2a and Figure 2b As shown. Therefore, the non-gain microchannel board 302 is only used as a channel and does not have a gain function.

[0039] Specifically, the gain-free microchannel plate 302 of this embodiment includes a first input surface 3021, a first output surface 3022, and a plurality of gain-free channels 3023. The first input surface 3021 and the first output surface 3022 of the gain-free microchannel plate 302 are parallel, with the first input surface 3021 facing the outside of the vacuum drift tube 10 and the first output surface 3022 facing the inside of the vacuum drift tube 10. The gain-free channels 3023 penetrate the gain-free microchannel plate 302, that is, the gain-free channels 3023 penetrate the first input surface 3021 and the first output surface 3022. The microstrip cathode 301 is deposited on the first input surface 3021 of the gain-free microchannel plate 302, and the grounded anode 303 is deposited on the entire first output surface 3022 of the gain-free microchannel plate 302.

[0040] The gated microchannel plate detector 40 is the core component of the gain-free microchannel plate two-dimensional framing imaging system. Its temporal resolution is determined by the ratio of its temporal resolution to the electron beam temporal magnification. The gated microchannel plate detector 40 includes an impedance gradient line 401, a microstrip line 402, a gain microchannel plate 403, a fluorescent screen 404, and a CCD camera. The gain microchannel plate 403 is a high spatial resolution, high-gain electron multiplier device, consisting of a thin glass sheet with numerous tiny vias (gain channels 4033). Each via acts as an independent electron multiplier, amplifying the electronic signal. Copper and gold layers, approximately 12 μm in length, are deposited at the input and output ports of each gain channel 4033, with the copper layer at the bottom and the gold layer at the top. Photons or electron signals are input to the channel wall surface of the gain channel 4033, generating primary electrons. When a large voltage is applied between the two end faces of the gain microchannel plate 403 through electrodes, an electric field is generated within each microchannel. This electric field accelerates primary electrons, causing them to propagate forward along the channel and collide with the inner wall of the channel to generate new secondary electrons. These secondary electrons are then accelerated and collide with the channel wall, repeating this process until they are emitted from the channel outlet, thus forming electron multiplication. Electrons are accelerated under the influence of the electric field between the output surface of the gain microchannel plate 403 and the fluorescent screen 404. The high-speed electrons bombard the phosphors of the fluorescent screen 404, emitting light and achieving electro-optic spatial and intensity conversion, producing a visible light image output. When there is no voltage or the voltage is too small to generate differential gain between the two end faces of the gain microchannel plate 403, all signals input to the gain microchannel plate 403 will be absorbed, and no image output will occur.

[0041] At a certain moment, the gated microchannel plate detector 40 samples and multiplies the time-amplified electron beam imaging a certain area of ​​the gain microchannel plate 403 using a gated pulse, and transmits it in a traveling wave manner on the microstrip line 402. At another moment, it samples and multiplies the electron beam in another area, such as... Figure 3 As shown, this allows for the acquisition of multiple images at different times.

[0042] Specifically, the gain microchannel plate 403 includes a second input surface 4031, a second output surface 4032, and multiple gain channels 4033, which penetrate the gain microchannel plate 403. A microstrip line 402 is deposited in a strip shape on the second input surface 4031 of the gain microchannel plate 403, and a preset metal layer is deposited on the entire second output surface 4032 of the gain microchannel plate 403. A pulse generator 50 is connected to the microstrip line 402 via an impedance gradient line 401, and the pulse generator 50 samples and multiplies the electron beam on the microstrip line 402 using gated pulses. The first surface of the fluorescent screen 404 is parallel to and spaced apart from the second output surface 4032 of the gain microchannel plate 403, and the second surface of the fluorescent screen 404 is in close contact with the CCD camera.

[0043] Furthermore, in the gain-free microchannel plate two-dimensional framing imaging system of this embodiment, the gain-free microchannel plate 302 has an outer diameter of 106 mm and a thickness of 1 mm. The gain-free channel 3023 has a diameter of 35 μm, the channel chamfer angle ranges from 6° to 8°, and the spacing between adjacent gain-free channels 3023 is 39 μm.

[0044] Three microstrip cathodes 301 are deposited on the first input surface 3021 of the gainless microchannel plate 302. The width of each microstrip cathode 301 is 12mm, and the interval between adjacent microstrip cathodes 301 is 10mm.

[0045] Furthermore, in the two-dimensional framing imaging system without gain microchannels in this embodiment, the gain microchannel plate 403 has an outer diameter of 106 mm and a thickness of 0.5 mm. Each gain channel 4033 has a channel diameter of 12 μm, a channel chamfer angle ranging from 6° to 8°, and a spacing of 14 μm between adjacent gain channels 4033.

[0046] Three microstrip lines 402 are deposited on the second input surface 4031 of the gain microchannel board 403. Each microstrip line 402 has a width of 12mm and the spacing between adjacent microstrip lines 402 is 10mm.

[0047] Furthermore, in the gain-free microchannel plate two-dimensional framing imaging system of this embodiment, copper and gold layers of a preset depth are deposited into the input and output ports of each gain channel 4033, with the copper layer located at the bottom layer and the gold layer located at the surface layer.

[0048] Furthermore, in the gain-free microchannel plate two-dimensional framing imaging system of this embodiment, the microstrip cathode 301 of the gain-free microchannel plate 302 includes a copper layer at the bottom and a gold layer at the top.

[0049] The ground anode 303 of the gainless microchannel plate 302 includes a copper layer at the bottom and a gold layer at the top.

[0050] The microstrip line 402 of the gated microchannel plate detector 40 includes a copper layer at the bottom and a gold layer at the top.

[0051] The pre-deposited metal layers on the entire second output surface 4032 of the gain microchannel board 403 include a copper layer at the bottom and a gold layer at the top.

[0052] Furthermore, in the gain-free microchannel plate two-dimensional framing imaging system of this embodiment, the thickness of the copper layer is 500 nm and the thickness of the gold layer is 100 nm.

[0053] refer to Figure 1 , Figure 4 and Figure 5In the gain-free microchannel plate two-dimensional framing imaging system of this embodiment, considering that the long magnetic lens has the advantage of good spatial resolution uniformity, while the short magnetic lens has the advantage of high spatial resolution, the two types of lenses are combined to form a long-short magnetic combined lens 20 to improve spatial resolution and uniformity. This allows the electron beam from the microstrip cathode 301 to be imaged at the same size on the gain microchannel plate 403, with an imaging magnification of 1:1. Alternatively, the long-short magnetic combined lens 20 of this embodiment includes a long magnetic lens 201, a first short magnetic lens 202, and a second short magnetic lens 203. The first short magnetic lens 202 surrounds the incident end of the vacuum drift tube 10, i.e., the first short magnetic lens 202 surrounds the gain-free electron beam time amplifier 30. The second short magnetic lens 203 surrounds the exit end of the vacuum drift tube 10, i.e., the second short magnetic lens 203 surrounds the gated microchannel plate detector 40. The long magnetic lens 201 surrounds between the incident end and the exit end of the vacuum drift tube 10.

[0054] In the gain-free microchannel plate two-dimensional framing imaging system of this embodiment, the first short magnetic lens 202 is composed of a ring-shaped soft iron and a copper coil. The copper coil is located inside the soft iron. There is a 4mm wide slit on the inner side of the first short magnetic lens 202, through which the magnetic field enters the electron drift region. The outer diameter of the first short magnetic lens 202 is 410mm, the inner diameter is 360mm, and the axial length is 100mm.

[0055] The second short magnetic lens 203 consists of a ring-shaped soft iron and a copper coil, with the copper coil located inside the soft iron. The inner side of the second short magnetic lens 203 has a 4mm wide slit through which the magnetic field enters the electron drift region. The outer diameter of the second short magnetic lens 203 is 410mm, the inner diameter is 360mm, and the axial length is 100mm.

[0056] Furthermore, in the gain-free microchannel plate two-dimensional framing imaging system of this embodiment, the long magnetic lens 201 is composed of copper enameled wire wound between the incident end and the exit end of the vacuum drift tube 10.

[0057] Furthermore, in the gainless microchannel plate two-dimensional framing imaging system of this embodiment, an imaging pinhole array 60 located on the input side of the gainless electron beam time amplifier 30 is also included. After the captured X-ray image passes through the imaging pinhole array 60, photoelectron images are generated at different positions of the microstrip cathode 301.

[0058] Furthermore, a negative DC voltage and a broadened pulse generated by the pulse generator 50 are superimposed on the microstrip cathode 301, and the two ends of the microstrip cathode 301 are simultaneously transmitted in opposite directions by two broadened pulses, and the waveforms of the two broadened pulses are the same. The grounded anode 303 is grounded.

[0059] like Figure 6aAs shown, the broadened pulse (cathode pulse 1) propagates from left to right in the microstrip cathode 301 at a propagation speed of v≈2×10⁻⁶. 8 m / s. At a certain moment, points A and B on the microstrip cathode 301 are synchronized at point A1 of the broadened pulse, and point B is synchronized at point B1. The voltage difference between points A1 and B1 is t·G, where t is the time required for the broadened pulse to travel from point B to point A, and G is the slope of the broadened pulse. Photoelectrons emitted at points A and B at the same moment have different transit times from the microstrip cathode 301 to the gain microchannel plate 403 due to the different accelerating voltages. To ensure that the two photoelectrons are within the same image, their transit time difference must be less than or equal to the time resolution T of the gain microchannel plate 403. MCP Then t≤T MCP / M, where M is the electron beam temporal magnification, and the camera temporal resolution is T≈T MCP Since the distance between points A and B is L = v·t ≤ v·T, the maximum image size is v·T. If the time resolution is 10 ps, ​​the image size is within 2 mm.

[0060] To increase the image size, a two-way stretching pulse counter-transmission method is adopted to ensure that the voltage of the entire microstrip cathode 301 is consistent.

[0061] like Figure 6b As shown, two pulse broadening signals (cathode pulse 1 and cathode pulse 2) are transmitted simultaneously from both ends of the microstrip cathode 301. At a certain moment, the voltage at point C on the microstrip cathode 301 is the sum of the voltage at point C1 of pulse broadening 1 and the voltage at point C2 of pulse broadening 2. Figure 6b As can be seen, since the two broadening pulses are transmitted simultaneously from both ends of the microstrip cathode 301, the voltage of the entire microstrip cathode 301 is consistent. Therefore, the photoelectron transit time from the microstrip cathode 301 to the gain microchannel plate 403 is the same, and the image size is not limited by the camera's temporal resolution, thus increasing the image size. It should be noted that when synchronized with the light pulse, the starting points O1 and O2 of the broadening pulse have both passed through the ending points of the microstrip cathode 301 in their respective transmission directions.

[0062] Alternatively, the gainless microchannel plate two-dimensional framing imaging system also includes an oscilloscope, an attenuator, and a capacitor. The oscilloscope is connected to one end of the capacitor via the attenuator, and the other end of the capacitor is connected to the microstrip cathode 301, which has acquired and displayed the waveform of the microstrip cathode 301.

[0063] Furthermore, the working principle of this gain-free microchannel plate two-dimensional framing imaging system is as follows:

[0064] Plasma X-ray radiation serves as the X-ray image to be captured. This captured X-ray image is then processed by an imaging pinhole array 60, generating photoelectron images at different positions on a microstrip cathode 301. A negative DC high voltage is applied to the microstrip cathode 301 and a broadened pulse is superimposed on it. The grounded anode 303 is grounded, synchronizing the X-rays at the rising edge of the broadened pulse. This ensures that the photoelectrons emitted earlier receive greater energy than those emitted later, thus causing the earlier electrons to travel faster.

[0065] After the photoelectrons propagate through the drift region from the ground anode 303 to the gain microchannel plate 403, the temporal width of the electron beam is broadened. The broadened electron beam is then imaged onto the microstrip line 402 corresponding to the input surface of the gain microchannel plate 403 by the long and short magnetic combination lens 20. If the electron beam is not synchronized with the gating pulse, the electron image will be absorbed by the gain microchannel plate 403, and no image will be output. When a very narrow gating pulse propagates along the microstrip line, only a section of the microstrip has voltage at a certain moment. The electron image imaged in this region by the long and short magnetic combination lens 20 will be enhanced by the gain microchannel plate 403 and projected onto the fluorescent screen 404 to form a visible light image. After a certain transmission time, the gating pulse reaches another electron image region, at which point the image is output. In this way, these electron images will be selected sequentially, and the output image will be recorded by a CCD camera. Because the electron beam is amplified in time, a very high camera temporal resolution can be obtained by using a gated microchannel plate detector 40 with a lower temporal resolution.

[0066] This embodiment uses electron beam time magnification technology to improve the temporal resolution of the framing camera, and uses a gainless microchannel plate electron beam time amplifier to improve the uniformity of temporal resolution and gain. It also uses a combination of long and short magnetic lenses to improve spatial resolution and its uniformity, and uses a two-way widened pulse counter-transmission method to increase the effective image size, thereby improving the various performance indicators of the framing camera.

[0067] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.

[0068] Those skilled in the art will further recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of the various examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this invention.

[0069] The steps of the methods or algorithms described in conjunction with the embodiments disclosed herein can be implemented directly by hardware, a software module executed by a processor, or a combination of both. The software module can be located in random access memory (RAM), main memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disk, removable disk, CD-ROM, or any other form of storage medium known in the art.

[0070] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They do not limit the scope of protection of the present invention. All equivalent changes and modifications made within the scope of the claims of the present invention should fall within the scope of the claims of the present invention.

Claims

1. A gain-free microchannel plate two-dimensional framing imaging system, characterized in that, The device includes a vacuum drift tube (10), a long and short magnetic combination lens (20), a gainless electron beam time amplifier (30), a gated microchannel plate detector (40), and a pulse generator (50). The long and short magnetic combination lens (20) surrounds the outside of the vacuum drift tube (10). The gainless electron beam time amplifier (30) is located at the incident end of the vacuum drift tube (10). The gated microchannel plate detector (40) is located at the exit end of the vacuum drift tube (10). The area between the incident end and the exit end inside the vacuum drift tube (10) is the electron drift region. The gainless electron beam time amplifier (30) includes a microstrip cathode (301), a gainless microchannel plate (302), and a grounded anode (303). The gainless microchannel plate (302) includes a first input surface (3021), a first output surface (3022), and a plurality of gainless channels (3023). The first input surface (3021) and the first output surface (3022) of the gainless microchannel plate (302) are parallel, and the gainless channels (3023) penetrate the gainless microchannel plate (302). The microstrip cathode (301) is deposited on the first input surface (3021) of the gainless microchannel plate (302), and the grounded anode (303) is deposited on the entire first output surface (3022) of the gainless microchannel plate (302). A negative DC voltage and a broadened pulse generated by the pulse generator (50) are superimposed on the microstrip cathode (301), and the two ends of the microstrip cathode (301) are transmitted simultaneously to each other by two broadened pulses, and the waveforms of the two broadened pulses are the same. The grounded anode (303) is grounded. The gated microchannel plate detector (40) includes an impedance gradient line (401), a microstrip line (402), a gain microchannel plate (403), a fluorescent screen (404), and a CCD camera. The gain microchannel plate (403) includes a second input surface (4031), a second output surface (4032), and multiple gain channels (4033), which penetrate the gain microchannel plate (403). The microstrip line (402) is deposited in a strip shape on the second input surface (4031) of the gain microchannel plate (403). A preset metal layer is deposited on the entire second output surface (4032) of the gain microchannel plate (403); the pulse generator (50) is connected to the microstrip line (402) through the impedance gradient line (401), and the pulse generator (50) samples and multiplies the electron beam on the microstrip line (402) through a gated pulse; the first surface of the fluorescent screen (404) is parallel to and spaced apart from the second output surface (4032) of the gain microchannel plate (403), and the second surface of the fluorescent screen (404) is in close contact with the CCD camera.

2. The gain-free microchannel plate two-dimensional framing imaging system according to claim 1, characterized in that, The gain-free microchannel plate (302) has an outer diameter of 106 mm and a thickness of 1 mm; the gain-free channel (3023) has a diameter of 35 μm, the channel bevel angle ranges from 6° to 8°, and the spacing between adjacent gain-free channels (3023) is 39 μm. Three microstrip cathodes (301) are deposited on the first input surface (3021) of the gain-free microchannel plate (302). Each microstrip cathode (301) has a width of 12 mm and a spacing of 10 mm between adjacent microstrip cathodes (301).

3. The gain-free microchannel plate two-dimensional framing imaging system according to claim 1, characterized in that, The gain microchannel plate (403) has an outer diameter of 106 mm and a thickness of 0.5 mm; each gain channel (4033) has a channel diameter of 12 μm, a channel chamfer angle ranging from 6° to 8°, and a spacing of 14 μm between adjacent gain channels (4033). Three microstrip lines (402) are deposited on the second input surface (4031) of the gain microchannel plate (403). Each microstrip line (402) has a width of 12 mm and the spacing between adjacent microstrip lines (402) is 10 mm.

4. The gain-free microchannel plate two-dimensional framing imaging system according to claim 3, characterized in that, Each of the gain channels (4033) has a copper layer and a gold layer of a preset depth deposited into its input and output ports, with the copper layer located at the bottom layer and the gold layer located at the top layer.

5. The gain-free microchannel plate two-dimensional framing imaging system according to claim 1, characterized in that, The microstrip cathode (301) of the gain-free microchannel plate (302) includes a copper layer at the bottom and a gold layer at the top. The ground anode (303) of the gain-free microchannel plate (302) includes a copper layer at the bottom and a gold layer at the top. The microstrip line (402) of the gated microchannel plate detector (40) includes a copper layer at the bottom and a gold layer at the top. The preset metal layer deposited on the entire second output surface (4032) of the gain microchannel plate (403) includes a copper layer at the bottom and a gold layer at the top.

6. The gain-free microchannel plate two-dimensional framing imaging system according to claim 5, characterized in that, The copper layer has a thickness of 500 nm, and the gold layer has a thickness of 100 nm.

7. The gain-free microchannel plate two-dimensional framing imaging system according to claim 1, characterized in that, The combined long and short magnetic lens (20) includes a long magnetic lens (201), a first short magnetic lens (202), and a second short magnetic lens (203). The first short magnetic lens (202) surrounds the incident end of the vacuum drift tube (10), the second short magnetic lens (203) surrounds the exit end of the vacuum drift tube (10), and the long magnetic lens (201) surrounds between the incident end and the exit end of the vacuum drift tube (10).

8. The gain-free microchannel plate two-dimensional framing imaging system according to claim 7, characterized in that, The first short magnetic lens (202) is composed of a ring-shaped soft iron and a copper coil. The copper coil is located inside the soft iron. There is a 4mm wide slit on the inner side of the first short magnetic lens (202). The outer diameter of the first short magnetic lens (202) is 410mm, the inner diameter is 360mm, and the length in the axial direction is 100mm. The second short magnetic lens (203) is composed of a ring-shaped soft iron and a copper coil. The copper coil is located inside the soft iron. There is a 4mm wide slit on the inner side of the second short magnetic lens (203). The outer diameter of the second short magnetic lens (203) is 410mm, the inner diameter is 360mm, and the length in the axial direction is 100mm.

9. The gain-free microchannel plate two-dimensional framing imaging system according to claim 7, characterized in that, The long magnetic lens (201) is composed of copper enameled wire wound between the incident end and the exit end of the vacuum drift tube (10).

10. The gain-free microchannel plate two-dimensional framing imaging system according to claim 1, characterized in that, It also includes an imaging pinhole array (60) located on the input side of the gainless electron beam time amplifier (30), through which the captured X-ray image is generated as a photoelectron image at different positions on the microstrip cathode (301).

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