High-temporal-spatial-resolution curved-surface cathode long-slit streak image converter tube

Abstract

The invention relates to a high-temporal-spatial-resolution curved-surface cathode long-slit streak image converter tube which is mainly used for solving the technical problems that an existing streak tube with a large cathode detection area cannot meet the requirements of high temporal resolution, high spectral resolution, continuous two-dimensional imaging and the like at the same time. The invention discloses a high-temporal-spatial-resolution curved-surface cathode long-slit streak image converter tube which comprises an insulating shell, a signal input window and an image output window which are arranged on the two sides of the insulating shell, and a spherical photoelectric cathode, a spherical grid electrode, a focusing electrode, an anode, a deflection plate, a conductive cylinder and a fluorescent screen which are sequentially arranged in the insulating shell along an optical axis. The photoelectric cathode and the grid electrode are both spherical sheets, namely, the curved surface photoelectric cathode structure and the curved surface grid electrode are adopted, the problem that the long-slit streak tube is low in spatial resolution is solved, and meanwhile the long-slit streak tube has high brightness gain and a large dynamic range and can be suitable for multiple research fields.

Description

Technical Field

[0001] The invention relates to a stripe image converter tube, in particular to a stripe image converter tube with high temporal and spatial resolution and curved cathode with long slits. Background Art

[0002] Streak cameras can be used for ultrafast diagnosis of strong laser-induced plasma, laser radar, ultrafast spectroscopy and other research. Streak image converters are the core components of streak cameras. The process of strong laser physics has the characteristics of fast evolution, small spatial scale, wide spectral range, etc., and the plasma radiation intensity is low at the beginning of the interaction between laser and matter, while the radiation intensity at the peak and the beginning is quite different. Therefore, streak cameras are required to have long cathodes (cathode length ≥ 30mm), high temporal resolution (<10ps), high spatial resolution (more than ten microns) and large dynamic range.

[0003] In the streak tube imaging lidar (STIL) system, the streak tube serves as the core detector for echo reception. The larger the effective cathode size of the streak tube and the higher the spatial resolution, the larger the field of view of the STIL. The higher the temporal resolution, the higher the detection distance accuracy. Theoretically, a temporal resolution of 10ps can provide a high distance resolution of 1.5mm.

[0004] Traditional streak cameras are generally narrow slit imaging, which can only obtain one-dimensional spatial information of the target, and the other one-dimensional spatial information is lost. However, in some experimental observations, it is necessary to obtain the continuous two-dimensional evolution information of the plasma (two-dimensional space + time + intensity) to provide data for the study of the evolutionary symmetry of the observed target during the plasma evolution process. The use of streak cameras combined with compressed ultrafast photography (CUP) can expand the streak camera from one dimension to continuous two-dimensional spatial imaging, which is a common technical means to achieve ultrafast two-dimensional imaging.

[0005] CUP technology achieves high-resolution imaging, which requires the streak camera to have a large detection cathode (cathode width not less than 5mm) while ensuring high temporal and spatial resolution. The larger the cathode detection area, the higher the spatial resolution of the restored image. Therefore, in order to meet the needs of laser plasma ultrafast diagnosis, laser radar and two-dimensional ultrafast imaging, a high-gain, high-temporal and high-resolution large-area streak tube is needed to see a wider spectral range. The effective size of the cathode is required to be ≥30mm×5mm, the time resolution is <10ps, and the spatial resolution is ≥30lp / mm.

[0006] At present, the long slit stripe image converter tubes with continuous two-dimensional imaging technology are typically the British Photek company ST-Y, the French Photonis company P510, and the Xi'an Institute of Optics and Precision Mechanics 6200. Their cathode length can reach 35mm and the width is 3-5mm, but the time resolution is low (50-300ps). Therefore, the existing long slit stripe image converter tubes with large cathode area and high spectral resolution cannot meet the technical requirements of high time resolution and high spatial resolution at the same time. Summary of the invention

[0007] The purpose of the present invention is to solve the technical problem that the existing long slit stripe image converter tube with large cathode area and high spectral resolution cannot simultaneously meet high temporal resolution and high spatial resolution, and to propose a high temporal and spatial resolution curved cathode long slit stripe image converter tube.

[0008] To solve the above technical problems, the technical solutions provided by the present invention are as follows:

[0009] A high time-space resolution curved cathode long slit fringe image converter tube, which is special in that it comprises a signal input window, an insulating shell and an image output window; the signal input window and the image output window are respectively arranged on two opposite sides of the insulating shell along the optical axis, and the insulating shell, the signal input window and the image output window form a closed vacuum body;

[0010] The invention also includes a slit, a photocathode, a grid, a focusing electrode, an anode, a deflection plate, a conductive cylinder and a fluorescent screen which are sequentially arranged in the vacuum body along the optical axis; the photocathode, the grid and the focusing electrode are used to load a working voltage; the anode, the conductive cylinder and the fluorescent screen are all grounded;

[0011] The signal input window is used to receive the optical signal; the slit is located between the signal input window and the photocathode and is used to pass the optical signal;

[0012] The photocathode is a spherical sheet, which is arranged near the inner surface of the signal input window, and its outer spherical surface protrudes toward the signal input window; a photoelectric emission material is arranged on the inner spherical surface of the photocathode, which is used to convert the photons of the optical signal into photoelectrons;

[0013] The gate is a spherical sheet, the outer spherical surface of which protrudes toward the photocathode, and a gap is provided between the gate and the photocathode; the inner spherical surface of the photocathode has the same curvature radius as the outer spherical surface of the gate; a rectangular opening is provided at the center of the gate, the long side direction of the opening is consistent with the direction of the slit length, and is used for photoelectrons to pass through; a working voltage is applied between the photocathode and the gate to form a cathode field strength, which is used for accelerating the photoelectrons;

[0014] The focusing electrode is a thin-walled cylindrical electrode, which is used to focus the accelerated photoelectrons to form an electron beam; a gap is provided between the focusing electrode and the grid;

[0015] The anode includes an anode cap and a cone section; the anode cap extends into the rear end of the focusing electrode, and a circular or rectangular aperture hole is provided on the anode cap for passing the electron beam; the anode cap is connected to the small end of the cone section;

[0016] The deflection plate is arranged in the cone section and is parallel to the slit direction; the deflection plate is used to control the landing position of the electron beam on the fluorescent screen; a linear time-varying ramp voltage is loaded on the deflection plate; the front end of the conductive cylinder is connected to the large end of the cone section; the fluorescent screen is connected to the rear end of the conductive cylinder and is used to receive the electron beam and form an image, and the image output window is used to output the light image generated on the fluorescent screen.

[0017] Further, the deflection plate comprises two trapezoidal bifold plates symmetrically arranged along the signal propagation direction;

[0018] Each of the trapezoidal two-fold plates comprises a parallel section and a deflection section, and the two parallel sections are arranged in parallel;

[0019] The front end of each parallel segment is close to the aperture and has a gap with the aperture, and the rear end of the parallel segment is connected to the front end of the deflection segment;

[0020] The distance between the two deflection segments gradually increases in the direction from the optical axis toward the conductive cylinder, forming a trapezoidal structure.

[0021] Furthermore, the focusing electrode comprises a first focusing electrode and a second focusing electrode sequentially arranged along the transmission direction of the photoelectrons; the first focusing electrode and the second focusing electrode are both thin-walled cylindrical electrodes, and a gap is provided between them; the first focusing electrode is used to preliminarily adjust the divergence degree of the photoelectrons, and the second focusing electrode is used to further focus;

[0022] The axial length of the first focusing electrode is smaller than the axial length of the second focusing electrode;

[0023] The radius of the first focusing electrode is smaller than the radius of the second focusing electrode.

[0024] Furthermore, the photocathode, the grid, the first focusing electrode and the second focusing electrode are isolated and sealed from each other by using ceramic rings and Kovar alloy; the anode, the conductive cylinder and the fluorescent screen are electrically connected.

[0025] Furthermore, the cathode grid field strength is greater than 0.25 kV / mm;

[0026] The size of the opening on the grid is ≥36mm×6mm.

[0027] Furthermore, the insulating shell is composed of ceramic, glass and metal;

[0028] The signal input window material is optical fiber panel or quartz glass;

[0029] The conductive cylinder is a metal cylinder or a glass shell with aluminum-plated inner surface.

[0030] Furthermore, the anode also includes a cylindrical section connected between the anode cap and the conical section, and the cylindrical section is used to provide a relatively stable electric field environment; the deflection plate is arranged in the cylindrical section and the conical section.

[0031] Furthermore, the voltage difference between the photocathode and the anode is 10-15 kV.

[0032] Furthermore, the fluorescent screen is a spherical structure, and the outer spherical surface protrudes toward the image output window.

[0033] Furthermore, the fluorescent screen is in a planar form.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] 1. The high temporal and spatial resolution curved cathode long slit stripe image converter tube of the present invention comprises an insulating shell, a signal input window and an image output window arranged on both sides of the insulating shell, and a spherical photocathode, a spherical grid, a focusing electrode, an anode, a deflection plate, a conductive cylinder and a fluorescent screen arranged in sequence in the insulating shell along the optical axis. The photocathode and the grid of the present invention are both spherical thin sheets, that is, the curved photocathode structure and the curved grid are adopted, which solves the problem of low spatial resolution of the long slit stripe tube, and at the same time has high brightness gain and a large dynamic range, and can be applied to multiple research fields.

[0036] 2. The high time and space resolution curved cathode long slit stripe image converter tube of the present invention has a rectangular opening size of ≥36mm×6mm on the grid, so that the effective size of the photocathode can reach 36mm×6mm; the ultimate time resolution is better than 5ps, the cathode grid field strength is higher than 0.25kV / mm, and the center spatial resolution of the stripe image converter tube can be higher than 40lp / mm, and the edge spatial resolution can be higher than 12lp / mm.

[0037] 3. In the high time-space resolution curved cathode long slit stripe image converter tube of the present invention, the light signal is accelerated for the first time from the photocathode to the grid, and from the grid to the first focusing electrode, which can quickly increase the electron running speed and reduce physical time dispersion; the electron beam is accelerated for the second time from the second focusing electrode to the anode, thereby ensuring that the ultimate time resolution of the stripe tube is better than 5ps.

[0038] 4. In the high time-space resolution curved cathode long slit fringe image converter tube of the present invention, there is a voltage difference of 10 to 15 kV between the photocathode and the anode, forming a strong acceleration field, so that the electron beam bombards the fluorescent screen at high speed, thereby improving the electroluminescent efficiency of the fluorescent screen.

[0039] 5. In the high time-space resolution curved cathode long slit fringe image converter tube of the present invention, the deflection plates adopt a symmetrically arranged trapezoidal two-fold plate structure, which can ensure a larger deflection sensitivity and electron beam deflection angle; the distance between the deflection segments gradually increases along the signal propagation direction to form a trapezoidal structure, which can prevent the electron beam from being affected by the edge field effect at the tail end of the deflection segment, thereby improving the consistency of the deflection sensitivity.

[0040] 6. In the high time-space resolution curved cathode long slit fringe image converter tube of the present invention, the anode includes an anode cap, which can intercept the large-angle photoelectrons generated by the photocathode to avoid the secondary electron noise generated at the anode entrance, and can also reduce the influence of the straight-through light on the imaging in practical applications. The aperture on the anode cap can ensure the passage of the electron beam, and at the same time can isolate the focusing area from the deflection area to reduce the mutual influence between the focusing field and the deflection field.

[0041] 7. In the high time-space resolution curved cathode long slit stripe image converter tube of the present invention, the opening size on the grid is greater than 36x6mm, so as to obtain a larger effective cathode length. The long side direction of the opening is the slit length direction, and the short side direction of the opening is the scanning direction. The electron beam converges twice in the slit length direction and the scanning direction, and the electron beam spot distribution in the convergence area is linear. The convergence point in the slit length direction is near the entrance of the deflection plate, and the convergence point in the scanning direction is at the middle or rear end of the deflection plate.

[0042] 8. In the high time-space resolution curved cathode long slit stripe image converter of the present invention, the axial length of the first focusing electrode is smaller than the axial length of the second focusing electrode, and the radius of the first focusing electrode is smaller than the radius of the second focusing electrode. By adjusting the radius, length, spacing and voltage of the first focusing electrode and the second focusing electrode, the beam spot distribution and image magnification of the electron beam on the fluorescent screen can be adjusted. The magnification of the stripe image converter of the present invention is 0.75 to 0.82, and the image is reduced, which has a convergence effect on the detection target and can improve the brightness gain. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 It is a structural schematic diagram of Embodiment 1 of the high temporal and spatial resolution curved cathode long slit fringe image converter tube of the present invention;

[0044] Figure 2 It is a schematic diagram of the structure of the photocathode and the grid in the embodiment of the high time and space resolution curved cathode long slit fringe image converter tube of the present invention;

[0045] Figure 3 It is a structural schematic diagram of Embodiment 2 of the high temporal and spatial resolution curved cathode long slit fringe image converter tube of the present invention;

[0046] Figure 4 It is a static spatial modulation transfer function curve diagram when y=0 in the first embodiment of the high temporal and spatial resolution curved cathode long slit fringe image converter tube of the present invention;

[0047] Figure 5 This is a relationship diagram between different Y-axis distances and static spatial resolution in Example 1 of the high temporal and spatial resolution curved cathode long slit fringe image converter tube of the present invention;

[0048] Figure 6 The distribution diagram of the electronic pulses with an interval of 5ps on the fluorescent screen in the first embodiment of the invention of the high time and space resolution curved cathode long slit fringe image converter tube;

[0049] Figure 7 for Figure 6 Normalized probability distribution curve of .

[0050] Description of reference numerals:

[0051] 1. Photocathode; 2. Grid; 3. First focusing electrode; 4. Second focusing electrode; 5. Anode; 6. Deflection plate; 7. Conductive cylinder; 8. Fluorescent screen; 9. Signal input window; 10. Insulating shell; 11. Image output window. DETAILED DESCRIPTION

[0052] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0053] Embodiment 1

[0054] The invention provides a high temporal and spatial resolution curved cathode long slit fringe image converter tube, such as Figure 1 As shown, it includes an insulating shell 10, a signal input window 9 and an image output window 11 respectively arranged on opposite sides of the insulating shell 10 along the optical axis, and a photocathode 1, a grid 2, a first focusing electrode 3, a second focusing electrode 4, an anode 5, a deflection plate 6, a conductive cylinder 7 and a fluorescent screen 8 located inside the insulating shell 10 and arranged in sequence along the optical axis.

[0055] The insulating shell 10, the signal input window 9 and the image output window 11 form a closed vacuum body, and the insulating shell 10 is made of ceramic, glass and metal.

[0056] The signal input window 9 is the entrance of the optical signal, and the material of the signal input window 9 is an optical fiber panel or quartz glass.

[0057] like Figure 2 As shown, the photocathode 1 is a spherical sheet, which is arranged on the inner surface of the signal input window 9. The photocathode 1 is a protruding outer spherical surface facing the signal input window 9, and a photoelectric emission material that receives an external incident light signal and emits photoelectrons is arranged on the inner spherical surface of the photocathode 1, which is used to convert the photons of the incident light signal into photoelectrons, thereby realizing the conversion of the light signal into the electrical signal. The photoelectric emission material can be selected according to the input light band.

[0058] The grid 2 is a spherical thin sheet, and the side thereof protruding toward the photocathode 1 is an outer spherical surface, which is adjacent to the photocathode 1 with a gap therebetween. A rectangular hole is provided at the center of the spherical surface of the grid 2, and the size of the rectangular hole is ≥36mm×6mm. By adjusting the working voltage of the grid 2, the electric field strength between the photocathode 1 and the grid 2, i.e., the cathode grid field strength, can be adjusted to control the number and speed of photoelectrons passing through the rectangular hole, thereby accelerating the photoelectrons emitted by the photocathode 1. The inner spherical curvature radius of the photocathode 1 is the same as the outer spherical curvature radius of the grid 2. In this embodiment, the cathode grid field strength is higher than 0.25kV / mm.

[0059] The first focusing electrode 3 and the second focusing electrode 4 are both thin-walled cylindrical electrodes, which are used to focus the photoelectrons accelerated by the grid 2 to form a fine electron beam. The first focusing electrode 3 is adjacent to the grid 2 on one side and adjacent to the second focusing electrode 4 on the other side, and a gap is maintained between the first focusing electrode 3 and both. The axial length of the first focusing electrode 3 is smaller than the axial length of the second focusing electrode 4. The first focusing electrode 3 is used to preliminarily adjust the divergence of the photoelectrons, and the second focusing electrode 4 is used for further fine focusing to focus the electron beam to a smaller spot size to meet the requirements of high spatial resolution. The radius of the first focusing electrode 3 is smaller than the radius of the second focusing electrode 4. The light signal undergoes two acceleration processes from the photocathode 1 to the fluorescent screen 8. The first acceleration is carried out between the photocathode 1-grid 2-first focusing electrode 3, which can quickly increase the running speed of the electrons and reduce the physical time dispersion; the electrons are accelerated for the second time from the second focusing electrode 4 to the anode 5, and the streak tube limit time resolution is better than 5ps.

[0060] The anode 5 is a three-section structure, including an anode cap, a cylindrical section and a conical section connected in sequence. The anode cap extends into the rear end of the second focusing electrode 4, and a circular or rectangular aperture is provided on the anode cap for passing the electron beam. The anode cap can intercept the large-angle electrons generated by the photocathode 1 to avoid secondary electron noise at the entrance of the anode 5, and can also reduce the influence of direct light on imaging in actual use. The aperture can ensure the passage of the electron beam, and at the same time, the focusing area can be isolated from the deflection area to reduce the mutual influence between the focusing field and the deflection field. The cylindrical section is connected to the small end of the conical section. The cylindrical section can provide a more stable electric field environment, which helps the electron beam to accelerate and move more smoothly therein. The conical section helps to further focus the electron beam, so that the electrons can bombard a specific area on the fluorescent screen 8 more concentratedly, thereby improving the spatial resolution and brightness of the imaging. In other embodiments, the anode 5 can be a two-section structure, including an anode cap and a conical section.

[0061] The deflection plate 6 is arranged in the conical section or the cylindrical section and the conical section of the anode 5, and is used to accurately control the landing position of the electron beam on the fluorescent screen 8. The deflection plate 6 includes two trapezoidal two-fold plates symmetrically arranged along the signal propagation direction. The trapezoidal two-fold plate includes a parallel section and a deflection section. The front end of the parallel section is close to the aperture and maintains a gap, and the rear end is connected to the front end of the deflection section. The distance between the deflection sections of the two trapezoidal two-fold plates gradually increases along the signal propagation direction to form a trapezoidal structure. The deflection plate 6 can ensure a larger deflection sensitivity and electron beam deflection angle; the distance between the rear ends of the two trapezoidal two-fold plates is increased, which can prevent the electron beam from being affected by the edge field effect of the tail end of the deflection plate 6, which helps to improve the consistency of the deflection sensitivity.

[0062] The slit is located before the photocathode. The light signal needs to pass through the slit before being irradiated on the photocathode. The slit limits the direction and range of light propagation, so that only light from a specific direction and area can reach the photocathode. Define the direction of light signal propagation, that is, the direction of the optical axis is the z-axis; Figure 2 As shown, the long side direction of the opening of the grid 2 is the direction of the slit length, which is defined as the x-axis; the short side direction of the opening is the scanning direction, which is defined as the y-axis. The electron beam converges twice in the slit length and scanning direction, and the electron beam spot distribution in the convergence area is linear. By adjusting the radius, length, spacing and voltage of the first focusing electrode 3 and the second focusing electrode 4, the intersection position of the electron beam in the slit length and scanning direction, as well as the beam spot distribution and image magnification of the electron beam on the fluorescent screen 8 can be adjusted. The convergence point of the electron beam along the slit length direction is near the entrance of the deflection plate 6, and the convergence point along the scanning direction is at the middle or rear end of the deflection plate 6.

[0063] The front end of the conductive cylinder 7 is connected to the large end of the conical cylinder section of the anode 5. The conductive cylinder 7 is a metal cylinder. In other embodiments, the conductive cylinder may also be a glass shell with an aluminum-plated inner surface. The conductive cylinder 7 mainly uses a shielding effect to keep its internal space from being affected by the electric field of other external electrodes and maintain the potential at 0V. Usually, this internal area is called a drift region. The electron beam drifts in the conductive cylinder 7 by itself and is not affected by the external electric field.

[0064] The fluorescent screen 8 is connected to the rear end of the conductive cylinder 7 and is used to receive the electron beam and form an image. In this embodiment, the fluorescent screen 8 is in the form of a spherical surface.

[0065] The image output window 11 is used to output the optical image generated on the fluorescent screen 8 .

[0066] The photocathode 1, the grid 2, the first focusing electrode 3, the second focusing electrode 4 and the deflection plate 6 are all loaded with working voltage; the anode 5, the conductive cylinder 7 and the fluorescent screen 8 are all grounded. There is a voltage difference of 10 to 15 kV between the photocathode 1 and the anode 5, forming a strong acceleration field, so that electrons bombard the fluorescent screen 8 at high speed, thereby improving the electroluminescent efficiency of the fluorescent screen 8.

[0067] The photocathode 1, the grid 2, the first focusing electrode 3, the second focusing electrode 4 and the anode 5 which are spaced a certain distance apart in sequence are isolated and sealed from each other by ceramic rings and Kovar alloy; the anode 5, the conductive cylinder 7 and the fluorescent screen 8 are electrically connected; the photocathode 1, the grid 2, the first focusing electrode 3, the second focusing electrode 4, the anode 5, the deflection plate 6, the conductive cylinder 7 and the fluorescent screen 8 are assembled by precision-machined jigs to ensure the concentricity and parallelism of each electrode.

[0068] The specific working process of the high time-space resolution curved cathode long slit fringe image converter is as follows: the target signal to be detected enters through the signal input window 9 and reaches the photocathode 1. The photocathode 1 generates photoelectrons under the action of the photoelectric effect; the photoelectrons carry the time, space, intensity, spectrum, temperature, density and other information of the target signal; the photoelectrons are accelerated by the gate 2, and then after the focusing modulation of the first focusing electrode 3 and the second focusing electrode 4, they are output from the aperture of the anode 5 and run to the deflection plate 6. The deflection plate 6 is loaded with a linear time-varying ramp voltage. Under the action of the ramp voltage, the electron beam deflects in the running direction, then drifts through the conductive cylinder 7, and finally forms an image on the fluorescent screen 8. Multiple target signals form fringe information on the fluorescent screen 8 according to the time before and after entering the signal input window 9, and finally output from the image output window 11. By collecting the image on the image output window 11 and analyzing its characteristics, the time, space, intensity, spectrum, temperature, density and other information carried by the detected target information can be obtained.

[0069] The three-dimensional electromagnetic simulation software CST is used to perform numerical simulation calculations on the electronic optics of the high time-space resolution curved cathode long slit stripe image converter tube of the present invention, wherein the z-axis is the optical axis, that is, the direction in which the cathode center points to the center of the fluorescent screen; the x-axis is the slit direction, that is, the direction of the long side of the grid opening; the y-axis is the scanning direction, that is, the direction of the short side of the grid opening. The deflection plate is parallel to the slit direction and perpendicular to the scanning direction. A point is taken at y=0, 1, 2, 3 mm, and at 0, 3, 6, 9, 12, 15, 16, 18 mm on the x-axis, and 3000 electrons are emitted from each point.

[0070] like Figure 4 As shown in the figure, it is a static spatial modulation transfer function (SMTF) curve when y=0. It is a function used to describe the transmission ability of the fringe image converter for signals of different spatial frequencies. When the SMTF value drops to a certain threshold (usually 0.1), the corresponding Figure 4 The horizontal spatial frequency in is considered to be the limiting spatial resolution of the fringe image converter. Figure 5 The figure shows the relationship between different axis distances and static spatial resolution.

[0071] Depend on Figure 4It can be seen that within the range of the effective area of ​​the photocathode of 36mm×6mm, the curves corresponding to y=0mm, x=0, 3, 6, 9, 12, 15, 16, and 18mm are Figure 4 When the vertical axis drops to 0.1, the corresponding values ​​of the horizontal axis are all greater than 15lp / mm, that is, the corresponding spatial resolution is higher than 15lp / mm. According to the magnification of 0.8, it is converted to 12lp / mm to the photocathode.

[0072] Depend on Figure 5 It can be seen that within the effective area of ​​the photocathode of 20mm×6mm, the spatial resolution at the edge point x=10, y=3, that is, the curve represented by y=3mm, is Figure 5 When the horizontal axis is 10, the corresponding vertical axis value is greater than 50lp / mm, that is, the spatial resolution is higher than 50lp / mm. According to the magnification of 0.8, it is converted to 40lp / mm on the cathode surface.

[0073] A sequence of electron pulses with a time interval of 5 ps (pulse width of 1 ps) is emitted from the center of the photocathode 1, and a ramp voltage is applied to the deflection plate 6, with a scanning speed of v = 0.144 × 108 m / s. Figure 6 As shown in FIG. 1 , it is a distribution diagram of electron pulses with an interval of 5 ps on the fluorescent screen 8, such as Figure 7 As shown, Figure 6 The normalized probability distribution curve of the photoelectron in the scanning direction has a saddle-peak ratio of about 0.46, which is less than the 0.7 required by the Rayleigh criterion, that is, the temporal resolution of the streak tube is better than 5ps.

[0074] The central spatial resolution of the high temporal and spatial resolution curved cathode long slit stripe image converter of the present invention is higher than 40lp / mm, and the edge spatial resolution is higher than 12lp / mm; the magnification of the present invention is 0.75-0.82, forming a reduced image, having a converging effect on the detection target, and improving the brightness gain.

[0075] Embodiment 2

[0076] The difference between this embodiment and the first embodiment is that Figure 3 As shown, the phosphor screen 8 is in a planar form.

Claims

1. A high temporal and spatial resolution curved cathode long slit fringe image converter tube, characterized in that: The device comprises a signal input window (9), an insulating shell (10) and an image output window (11); the signal input window (9) and the image output window (11) are respectively arranged on two opposite sides of the insulating shell (10) along the optical axis, and the insulating shell (10), the signal input window (9) and the image output window (11) form a sealed vacuum body; It also includes a slit, a photocathode (1), a grid (2), a focusing electrode, an anode (5), a deflection plate (6), a conductive cylinder (7) and a fluorescent screen (8) which are sequentially arranged in the vacuum body along the optical axis; the photocathode (1), the grid (2) and the focusing electrode are used to load a working voltage; the anode (5), the conductive cylinder (7) and the fluorescent screen (8) are all grounded; The signal input window (9) is used to receive light signals; the slit is located between the signal input window (9) and the photocathode (1) and is used to pass the light signal; the photocathode (1) is a spherical sheet, which is arranged close to the inner surface of the signal input window (9), and its outer spherical surface protrudes toward the signal input window (9); a photoelectric emission material is arranged on the inner spherical surface of the photocathode (1) and is used to convert the photons of the light signal into photoelectrons; The gate (2) is a spherical thin sheet, the outer spherical surface of which protrudes toward the photocathode (1), and a gap is provided between the gate and the photocathode (1); the inner spherical surface of the photocathode (1) has the same curvature radius as the outer spherical surface of the gate (2); a rectangular opening is provided at the center of the gate (2), the long side direction of the opening is consistent with the direction of the slit length, and is used for photoelectrons to pass through; an operating voltage is applied between the photocathode (1) and the gate (2) to form a cathode field strength, which is used for accelerating photoelectrons; The focusing electrode is a thin-walled cylindrical electrode, which is used to focus the accelerated photoelectrons to form an electron beam; a gap is provided between the focusing electrode and the grid (2); The anode (5) comprises an anode cap and a cone section; the anode cap extends into the rear end of the focusing electrode, and a circular or rectangular aperture is provided on the anode cap for passing the electron beam; the anode cap is connected to the small end of the cone section; The deflection plate (6) is arranged in the cone section and is parallel to the slit direction; the deflection plate (6) is used to control the landing point position of the electron beam on the fluorescent screen (8); a linear time-varying slope voltage is loaded on the deflection plate (6); the front end of the conductive cylinder (7) is connected to the large end of the cone section; the fluorescent screen (8) is connected to the rear end of the conductive cylinder (7) and is used to receive the electron beam and form an image; the image output window (11) is used to output the light image generated on the fluorescent screen (8).

2. The high temporal and spatial resolution curved cathode long slit fringe image converter tube according to claim 1, characterized in that: The deflection plate (6) comprises two trapezoidal bifold plates symmetrically arranged along the signal propagation direction; Each of the trapezoidal two-fold plates comprises a parallel section and a deflection section, and the two parallel sections are arranged in parallel; The front end of each parallel segment is close to the aperture and has a gap with the aperture, and the rear end of the parallel segment is connected to the front end of the deflection segment; The distance between the two deflection segments gradually increases in the direction from the optical axis toward the conductive cylinder (7), forming a trapezoidal structure.

3. The high temporal and spatial resolution curved cathode long slit fringe image converter tube according to claim 2, characterized in that: The focusing electrode comprises a first focusing electrode (3) and a second focusing electrode (4) which are sequentially arranged along the transmission direction of the photoelectrons; the first focusing electrode (3) and the second focusing electrode (4) are both thin-walled cylindrical electrodes, and a gap is provided between them; the first focusing electrode (3) is used to preliminarily adjust the divergence degree of the photoelectrons, and the second focusing electrode (4) is used to further focus; The axial length of the first focusing electrode (3) is smaller than the axial length of the second focusing electrode (4); The radius of the first focusing electrode (3) is smaller than the radius of the second focusing electrode (4).

4. The high temporal and spatial resolution curved cathode long slit fringe image converter tube according to claim 3, characterized in that: The photocathode (1), grid (2), first focusing electrode (3) and second focusing electrode (4) are isolated and sealed from each other by ceramic rings and Kovar alloy; the anode (5), conductive cylinder (7) and fluorescent screen (8) are electrically connected.

5. The high temporal and spatial resolution curved cathode long slit fringe image converter tube according to claim 4, characterized in that: The cathode grid field strength is greater than 0.25 kV / mm; The size of the opening on the grid (2) is ≥36 mm×6 mm.

6. The high temporal and spatial resolution curved cathode long slit fringe image converter tube according to claim 5, characterized in that: The insulating shell (10) is made of ceramic, glass and metal; The signal input window (9) is made of optical fiber panel or quartz glass; The conductive cylinder (7) is a metal cylinder or a glass shell with an aluminum-plated inner surface.

7. The high temporal and spatial resolution curved cathode long slit fringe image converter tube according to claim 6, characterized in that: The anode (5) further comprises a cylindrical section connected between the anode cap and the conical section, the cylindrical section being used to provide a relatively stable electric field environment; the deflection plate (6) is arranged inside the cylindrical section and the conical section.

8. The high temporal and spatial resolution curved cathode long slit fringe image converter tube according to claim 7, characterized in that: The voltage difference between the photocathode (1) and the anode (5) is 10 to 15 kV.

9. The high temporal and spatial resolution curved cathode long slit fringe image converter tube according to claim 8, characterized in that: The fluorescent screen (8) is a spherical structure, and the outer spherical surface protrudes toward the image output window (11).

10. The high temporal and spatial resolution curved cathode long slit fringe image converter tube according to claim 8, characterized in that: The fluorescent screen (8) is in a planar form.

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