Deflection compensation system for improving dynamic space distortion of small streak image converter tube

Abstract

The invention discloses a deflection compensation system for improving dynamic space distortion of a small streak image converter tube, and belongs to the field of streak cameras. According to the deflection compensation system, the high-voltage pulse falling edge is loaded on the compensation plate, and the feasibility of improving dynamic space distortion and improving spatial resolution uniformity is discussed. Research results show that V-type high-voltage pulses with the rising edge slope of 12.68 kV / ns and the falling edge slope of 15.22 kV / ns can be generated through the Marx circuit and the LC high-pass filter, the V-type high-voltage pulses are applied to the small streak image converter tube, before and after the deflection compensation technology is adopted, the electron offset range in the area 15 mm away from the axis is reduced to 5.87-6.58 mm from 6.01-8.15 mm, the maximum offset difference value on the relative axis is reduced to 0.71 mm from 2.14 mm, and the maximum offset difference value in the area 15 mm away from the axis is reduced to 5.87-6.58 mm. The maximum relative error is reduced to 12.09% from 35.61%; and the range of the maximum difference value relative to the dynamic spatial resolution on the axis is reduced from 109.37 lp / mm to 103.36 lp / mm, and the maximum relative error is reduced from 75.19% to 71.05%. According to the method, the imaging deflection degree and the dynamic spatial resolution uniformity in the detection area are quantified, the deflection compensation technology can reduce the influence of dynamic spatial distortion and improve the spatial resolution uniformity, and an effective thought and method are provided for the streak camera field.

Description

Technical Field

[0001] The present invention relates to the field of streak cameras, and more particularly to a deflection compensation system for improving dynamic spatial distortion of a small streak image converter tube. Background Art

[0002] A streak camera is an ultrafast diagnostic instrument based on a scanning image converter tube. Its core component, the streak converter tube, converts the temporal information of an optical signal into spatial position information. In conjunction with a spectral spectrometer (e.g., a grating or prism), it records the spectral intensity. As a complete diagnostic instrument, the streak camera can effectively acquire three-dimensional spatial-intensity-temporal information about transient plasma processes during inertial confinement fusion (ICF) experiments. In recent years, with the advancements and breakthroughs in ICF experiments, the detection area of ​​streak converter tubes has been expanded to meet the demand for collecting comprehensive soft X-ray information across a wide spectrum. However, as the detection area increases, the inherent dynamic spatial distortion of streak converter tubes becomes increasingly significant. This not only severely impacts the uniformity of dynamic spatial resolution within the detection area, but also affects the temporal distribution of the streak converter electrons, temporal distortion, spherical aberration, and deflection defocus. This significantly reduces image quality and dynamic spatial resolution at the edges of the detection area, hindering the development of compact streak converter tubes with large detection areas. Therefore, the improvement of dynamic spatial distortion has important theoretical and practical significance for the design and research of large-area, high-performance small-scale stripe image converter tubes.

[0003] In small streak image converter tubes, dynamic spatial distortion (DSD) is caused by the influence of axially symmetrical non-uniform electric fields and deflection scanning pulses, resulting in different off-axis electron imaging deflections. Methods for improvement include curved cathodes, spherical phosphor screens, and electric lens correction. In the method using curved cathodes and spherical phosphor screens, researchers calculated the optimal curvature radius of the cathode and image plane to improve dynamic spatial distortion. However, since the curvature radius of the cathode and image plane varies across tube types, it is difficult to obtain a universal solution. In the electric lens correction method, researchers designed a correction lens in front of the anode entrance based on the off-axis electric field distribution. This improved dynamic spatial distortion by changing the electric field and field curvature. However, because the correction lens uses a thick lens, it increases the length of the focusing zone and restricts further improvements in temporal resolution.

[0004] To explore a universal method for improving dynamic spatial distortion with minimal negative impact, a small-scale streak image converter model was first established to analyze the formation principle of dynamic spatial distortion in the streak image converter and its impact on dynamic spatial resolution performance. Then, a compensation plate was designed, the deflection and its compensation sensitivity were calculated, and the basic principle of deflection compensation technology in improving dynamic spatial distortion was analyzed. Finally, a V-shaped high-voltage pulse was designed using a Marx circuit and an LC high-pass filter. Based on the deflection compensation technology, the electric pulse was simultaneously applied to the deflection plate and the deflection compensation system to achieve improvement in dynamic spatial distortion. The improvement effect was quantified based on the relative error principle. Summary of the Invention

[0005] The deflection electric field in small streak converter tubes not only causes electronic imaging deflection and curvature of the fringe image, but also creates dynamic spatial distortion, which reduces spatial resolution uniformity and hinders the development of large-area small streak converter tubes. While the use of curved cathodes, spherical phosphor screens, and electric lens correction can improve distortion characteristics, they also pose challenges in generalization and restrict improvements in temporal resolution. To further address this issue, the present invention provides a deflection compensation system for use in small streak converter tubes. By applying the trailing edge of a high-voltage pulse to the deflection compensation system, this system addresses the prior art's inability to meet the requirements of high temporal resolution, high spectral resolution, and continuous two-dimensional imaging for streak converter tubes.

[0006] The technical solutions of the present invention are as follows:

[0007] The small streak image converter provided by the present invention mainly comprises an acceleration area, a focusing area, an anode, a scanning deflection plate, a compensation plate and a fluorescent screen.

[0008] The total tube length of the small stripe image converter tube is 120 mm.

[0009] The acceleration zone includes a photocathode and a grid. The photocathode voltage is -15 kV and the grid voltage is -14.7 kV.

[0010] The focusing area includes a first focusing electrode and a second focusing electrode. The voltage of the first focusing electrode is -14.2 kV, and the voltage of the second focusing electrode is -13.0 kV.

[0011] The anode is grounded and the voltage is 0 kV.

[0012] Preferably, the voltage difference between the photocathode and the anode is 15 kV.

[0013] The axial width of the scanning deflection plate is 18.2 mm, the heights of the entrance and exit are 2 mm and 18.4 mm respectively, and the distance between the exit and the fluorescent screen is 33 mm.

[0014] Preferably, a pair of rectangular deflection plates tilted up and down are designed between the scanning deflection plate and the fluorescent screen as compensation plates.

[0015] The axial width of the compensation plate is 13.8 mm, the heights of the inlet and outlet are 14 mm and 25.4 mm respectively, and the distance between the outlet and the fluorescent screen is 5 mm.

[0016] Preferably, a V-shaped high-voltage pulse is designed using a Marx circuit and an LC high-pass filter for application to the compensation plate of a small streak image converter tube. Its rising and falling edge times are 0.33ns and 0.275ns, respectively, with a peak value of -4.186kV, and average slopes of 12.68kV / ns and 15.22kV / ns, respectively.

[0017] The DC power supply HV in the Marx circuit is 1.6kV, the amplitude and frequency of the trigger signals T1~T5 are 12V and 10kHz respectively, the resistors R1~R10 are 100kΩ, R11~R20 are 10Ω, the charging capacitors C1~C5 are 3nF, C6~C10 are 0.1μF, the avalanche diodes D1~D5 are IN4007, and the avalanche transistors Q1~Q10 are 2N5551.

[0018] In the LC high-pass filter, the inductors L1 and L2 are 440 nH and 16 nH respectively, the inductors C11 and C12 are 1 pF, and the load resistor R is 200 Ω.

[0019] The phosphor screen voltage is 3.4 kV.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] 1. This invention achieves dynamic compensation for off-axis electron deflection by adding a compensation plate between the scanning deflection plates and the phosphor screen of a small streak image converter tube and applying a V-shaped high-voltage pulse (rising slope of 12.68 kV / ns, falling slope of 15.22 kV / ns). Compared with existing technologies, the electron deflection range within a 15 mm off-axis region is reduced from 6.01 to 8.15 mm to 5.87 to 6.58 mm, the maximum offset difference on the relative axis is reduced from 2.14 mm to 0.71 mm, and the maximum relative error is reduced from 35.61% to 12.09%, effectively suppressing the curvature of the fringe image.

[0022] 2. The dynamic spatial distortion of existing streak image converters can significantly reduce off-axis resolution. However, the present invention utilizes deflection compensation technology to reduce the maximum difference in dynamic spatial resolution from 109.37 lp / mm to 103.36 lp / mm in the off-axis region within 15mm, and the maximum relative error from 75.19% to 71.05%. This significantly reduces the resolution degradation in edge regions and improves spatial resolution uniformity within the detection area, meeting the requirements of large-area imaging.

[0023] 3. Unlike solutions like curved cathodes and spherical screens that rely on customized tube curvature, this invention utilizes an independent compensation plate structure and adjustable-slope V-shaped pulses, eliminating the need to modify the curvature of the fringe converter tube's core electrode, allowing it to adapt to detection areas of varying sizes. Furthermore, it avoids the degradation in temporal resolution caused by thick lenses during electric lens correction, ensuring unrestricted ultimate temporal resolution.

[0024] 4. A V-shaped pulse generator, combining a Marx circuit with an LC high-pass filter, produces ultrafast pulses with a rising edge of 0.33ns and a falling edge of 0.275ns. Dynamic compensation is achieved through the rising / falling slope difference (2.54kV / ns). Compared to traditional linear pulses, this waveform dynamically adjusts the compensation voltage based on the timing of off-axis electron deflection, enabling differentiated compensation for electrons at different off-axis positions in the streak image converter tube, improving compensation accuracy by over 30%.

[0025] 5. In the miniaturized streak image converter design with a total tube length of 120mm, the axial width of the compensation plate is only 13.8mm, and the distance between the outlet and the phosphor screen is 5mm, which does not increase the additional space. It is suitable for ultrafast diagnostic scenarios such as inertial confinement fusion (ICF) that are sensitive to device size.

[0026] 6. While improving spatial distortion, the present invention avoids the negative impact of existing correction technologies on temporal resolution. Combined with a strong acceleration field design (cathode-anode voltage difference of 15kV), it can simultaneously achieve high-performance indicators of temporal resolution better than 5ps and spatial resolution of 145lp / mm, meeting the requirements for high-precision acquisition of "space-intensity-time" three-dimensional information during plasma transient processes. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a schematic diagram of a small streak image converter tube model of a deflection compensation system for improving dynamic spatial distortion of a small streak image converter tube according to the present invention;

[0028] Figure 2 This is a schematic diagram of the electric field distribution on the axis and 15 mm off the axis of a deflection compensation system for improving the dynamic spatial distortion of a small streak image converter tube according to the present invention;

[0029] Figure 3The invention relates to a deflection compensation system for improving the dynamic spatial distortion of a small-sized stripe image converter tube, and discloses an imaging distribution center position on a fluorescent screen and a fitting stripe curve thereof.

[0030] Figure 4 This is a dynamic spatial resolution curve of a deflection compensation system for improving dynamic spatial distortion of a small-sized streak image converter tube according to the present invention;

[0031] Figure 5 This is a schematic diagram of a model of a small stripe image converter tube deflection compensation system for improving the dynamic spatial distortion of a small stripe image converter tube according to the present invention;

[0032] Figure 6 This is a schematic diagram of the electronic deflection amount of the deflection plate of the deflection compensation system for improving the dynamic spatial distortion of a small-sized streak image converter tube according to the present invention;

[0033] Figure 7 This is a schematic diagram of the electronic deflection amount of the compensation plate by loading a deflection compensation pulse in a deflection compensation system for improving the dynamic spatial distortion of a small-sized streak image converter tube according to the present invention;

[0034] Figure 8 This is a schematic diagram of the electronic deflection amount of the scanning and deflection compensation pulses loaded simultaneously in a deflection compensation system for improving the dynamic spatial distortion of a small-sized fringe image converter tube according to the present invention;

[0035] Figure 9 This is a sensitivity fitting curve of a stripe image converter deflection plate of a deflection compensation system for improving dynamic spatial distortion of a small stripe image converter according to the present invention;

[0036] Figure 10 This is a sensitivity fitting curve of a stripe image converter compensation plate of a deflection compensation system for improving dynamic spatial distortion of a small stripe image converter tube according to the present invention;

[0037] Figure 11 This is a schematic diagram of the design of a high-voltage pulse generator for a deflection compensation system for improving dynamic spatial distortion of a small-sized streak image converter tube according to the present invention;

[0038] Figure 12 This is a schematic diagram of a V-shaped high-voltage pulse waveform of a deflection compensation system for improving dynamic spatial distortion of a small-sized streak image converter tube according to the present invention;

[0039] Figure 13 The invention discloses a deflection compensation system for improving dynamic spatial distortion of a small-sized streak image converter tube, which uses deflection compensation technology to improve imaging offset comparison of dynamic spatial distortion results.

[0040] Figure 14The present invention discloses a deflection compensation system for improving the dynamic spatial distortion of a small-sized streak image converter tube, which uses a deflection compensation technique to improve the relative error comparison between the dynamic spatial distortion result and the on-axis imaging offset.

[0041] Figure 15 The invention discloses a deflection compensation system for improving the dynamic spatial distortion of a small-sized streak image converter tube, which uses a deflection compensation technique to improve the dynamic spatial resolution comparison of the dynamic spatial distortion result.

[0042] Figure 16 The present invention is a deflection compensation system for improving the dynamic spatial distortion of a small streak image converter tube, and compares the relative error of the dynamic spatial distortion result improved by the deflection compensation technology with the on-axis dynamic spatial resolution.

[0043] Description of reference numerals:

[0044] 1. Photocathode; 2. Slit; 3. Grid; 4. Focusing electrode; 5. Discrete port; 6. Scanning deflection plate; 7. Scanning pulse; 8. Matching resistor; 9. Anode; 10. Compensation plate; 11. Deflection compensation pulse; 12. Fluorescent screen. DETAILED DESCRIPTION

[0045] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, Figure 1 To the attached Figure 16 The present invention is described in detail.

[0046] Figure 1 It is a schematic structural diagram of the small-sized streak image converter tube of the present invention.

[0047] Specifically, the streak image converter system includes an acceleration zone (photocathode 1 and grid 3), a focusing zone (first and second focusing electrodes 4), a scanning deflection plate 6, an anode 9, a compensation plate 10 and a fluorescent screen 12. The total tube length is 120 mm, the axial width of the deflection plate is 18.2 mm, the heights of the entrance and exit are 2 mm and 18.4 mm respectively, and the distance between the exit and the fluorescent screen is 33 mm.

[0048] Figure 2 Schematic diagram of the electric field distribution on axis and 15 mm off axis of the small fringe image converter tube of the present invention.

[0049] Specifically, when the photocathode voltage and grid voltage are -15 kV and -14.7 kV respectively, the two focusing electrodes are -14.2 kV and -13.0 kV respectively, the anode is 0 kV, and the screen voltage is 3.4 kV, the following electric field distribution will appear on the axis and 15 mm off the axis. At this time, the peak values ​​of the focusing area are -8.7×10 5 VM -1 and -7.6×10 5 VM-1 .

[0050] Figure 3 The diagram is a schematic diagram of the imaging distribution center position and the fitting fringe curve on the fluorescent screen of the small-sized fringe image converter tube of the present invention.

[0051] Specifically, based on the above electric field distribution, 10,000 photoelectrons were emitted from different off-axis positions within the 15mm area of ​​the cathode. Due to the influence of the deflection plate scanning pulse, as the off-axis distance increases, the imaging deflection range relative to the ideal imaging position is 6.01 to 8.15mm, and the relative deflection based on the on-axis electron imaging gradually increases to 2.14mm, and the curvature of the fringe image gradually becomes obvious.

[0052] Figure 4 It is a schematic diagram of the dynamic spatial resolution curve of the small-sized streak image converter tube of the present invention.

[0053] Specifically, in terms of spatial resolution, the imaging distribution of each emission position is used as a benchmark, and the spatial resolution method is calculated according to the Rayleigh criterion. Electrons are repeatedly emitted at different adjacent positions. By statistically analyzing the resolution distance and modulation index between the two imaging distribution peaks, a spatial modulation transfer function (MTF) curve is constructed, and the resolution distance when the modulation index is 0.1 is calibrated as the ultimate spatial resolution at a certain off-axis position. Preferably, the dynamic spatial resolution curve is calculated using the Rayleigh criterion. As the off-axis position changes, the dynamic spatial resolution gradually decreases from 145.44 lp / mm to 36.07 lp / mm, and the spatial resolution uniformity decreases significantly. It should be noted that the analysis results show that when the scanning pulse is applied to the deflection plate, since electrons at different off-axis positions are synchronized at different positions on the rising edge of the scanning pulse, they are subjected to different deflection forces. Therefore, the deflection amount of the electrons on the imaging surface is different, resulting in a dynamic spatial distortion phenomenon of fringe bending, and causing the dynamic spatial resolution uniformity within the detection area to deteriorate.

[0054] Figure 5 It is a schematic diagram of a model of a small-sized streak image converter tube deflection compensation system of the present invention.

[0055] Specifically, a pair of compensating plates, arranged in a vertically tilted configuration, are placed between the deflection plates and the screen. The plates have an axial width of 13.8 mm, entrance and exit heights of 14 mm and 25.4 mm, respectively, and a 5 mm distance between the exit and the screen. U1 represents a time-varying upward ramp pulse (with slope and intercept k1 and b1, respectively), while U2 represents a downward ramp pulse (with slope and intercept k2 and b2, respectively).

[0056] Figure 6Schematic diagram of the electronic deflection amount when a scanning pulse is loaded on the deflection plate of the small-sized streak image converter tube of the present invention.

[0057] Specifically, when only U1 is loaded on the deflection plate, the deflection difference Δy1 between on-axis and off-axis electron imaging is shown in the figure, where P1 is the deflection sensitivity of the deflection plate, t1 and t2 are the moments when the two electrons enter the deflection plate, and V1 and V2 are the deflection voltages received by the two electrons.

[0058] Figure 7 Schematic diagram of the electronic deflection amount when a deflection compensation pulse is loaded on the compensation plate of the small streak image converter tube of the present invention.

[0059] Specifically, when only U2 is loaded on the compensation plate, the electron imaging deflection difference Δy2 is shown in the figure, where P2 is the deflection sensitivity of the compensation plate, t3 and t4 are the moments when the two electrons enter the compensation plate, and V3 and V4 are the compensation voltages received by the two electrons.

[0060] Figure 8 Schematic diagram of the electronic deflection amount when the small-sized streak image converter tube of the present invention is loaded with scanning and deflection compensation pulses simultaneously.

[0061] Specifically, combining the principle of pulse deflection and compensation, when the deflection plate and compensation plate are loaded with U1 and U2 at the same time, the difference in electron deflection amount y c As shown in the figure, preferably, first, the scanning pulse on the deflection plate generates an upward deflection electric field force on both on-axis and off-axis electrons, causing the difference in deflection between the two to gradually increase when they reach the compensation plate. Then, under the action of the ramped downward pulse on the compensation plate, the two electrons are subjected to a downward electric field force, with the electrons farther from the axis being subjected to a greater compensation electric field force, and a certain amount of compensation is obtained. Finally, the difference in deflection between the on-axis and off-axis electron images is correspondingly reduced.

[0062] Further analysis shows that because the rising edge of the pulse is first applied to the deflection plates, electrons maintain their original deflection state as they pass through the plates. When electrons enter the compensation plate, their compensation effect is relatively small due to the synchronization with the initial position of the compensation pulse. However, off-axis electrons, affected by the electron deflection, are in the falling phase of the pulse's falling edge when entering the compensation plate, resulting in a gradually increasing compensation effect from the increasing voltage. This dynamic compensation method, which uses different voltages for different off-axis electrons, ensures that the overall scan slope of the small streak image converter tube is not a linear difference between the deflection plate and compensation plate scan slopes, but rather a dynamic value. This ultimately improves the curvature of the fringe image caused by varying degrees of curvature of off-axis electron imaging and enhances spatial resolution uniformity.

[0063] Figure 9Schematic diagram of the fitting curve of the sensitivity of the deflection plate of the small-sized streak image converter tube of the present invention.

[0064] Specifically, the sensitivity of a streak image converter refers to the degree of deviation of electrons from the ideal imaging position on the fluorescent screen when the deflection plates are loaded with different static voltages. It has a certain influence on its dynamic performance and is represented by the slope of a linear curve of static deflection voltage and electron offset. In a small streak image converter with a compensation plate, the sensitivity is divided into deflection and compensation. The calculation method follows the following process: first, different voltages are loaded on the deflection plate or the compensation plate, and a number of electrons are emitted from the cathode axis; then, by counting the electron imaging position, the deflection distance from the ideal imaging position is obtained; finally, the relationship between the deflection distance and voltage is established, and a deflection linear equation is constructed by linear fitting, and the deflection sensitivity is the slope of the curve. Preferably, based on Figure 1 The model parameters and electric field distribution conditions of the small streak image converter are shown in the figure. When the deflection plate loading voltage ranges from 0 to 1 kV, the fitting relationship between the on-axis electronic imaging deflection distance and the voltage is shown in the figure. The deflection linear equation is constructed, where the abscissa is the deflection plate voltage, the ordinate is the deflection amount, and 3.5 mm / kV is the deflection sensitivity.

[0065] Figure 10 Schematic diagram of the fitting curve of the sensitivity of the compensation plate of the small streak image converter tube of the present invention.

[0066] Specifically, when only a voltage ranging from -1 to 0 kV is applied to the compensation plate, the fitted relationship between the on-axis electron imaging deflection distance and voltage is shown in the figure. The constructed deflection linear equation has the compensation plate voltage on the abscissa and the deflection amount on the ordinate, with 0.302 mm / kV being the compensation plate's deflection sensitivity. It should be noted that because sensitivity is affected by the accelerating voltage, as well as the length and height of the deflection and compensation plates, the deflection and compensation sensitivities are relatively low in small streak converter tubes with high accelerating voltages and short tube lengths.

[0067] Figure 11 This is a schematic diagram of the design of a small-sized streak image converter tube high-voltage pulse generator according to the present invention.

[0068] Specifically, when using deflection compensation technology to improve the dynamic spatial distortion of a small streak image converter, it's necessary not only to apply an upward-sloping high-voltage pulse to the deflection plates, but also to apply a downward-sloping pulse to the compensation deflection plates. To avoid idealizing linear pulses, improve the reliability of the improvement, and better adapt to practical applications, a V-shaped high-voltage pulse design is employed using a Marx circuit and an LC high-pass filter. The circuit structure is shown in the figure.

[0069] Specifically, when the circuit system is working, the DC power supply HV first fully charges the charging capacitors C1 to C5 and then prepares for discharge, and then uses the trigger signals T1 to T5 to synchronously trigger the avalanche transistors Q1 to Q 10 After the avalanche transistor is turned on, the circuit system's operating state immediately changes from high voltage and low current to low voltage and high current. At this time, the current flows through the entire loop. When the current increases to the secondary breakdown critical value, all avalanche transistors will be secondary broken down. At this time, the Marx circuit outputs nanosecond ultra-fast high-voltage pulses; then, the pulse passes through the avalanche diodes D1~D5 and outputs a negative high-voltage pulse with opposite polarity; finally, the pulse passes through L1 and C 11 and L2, C 12 After the double-stage LC high-pass filter circuit is formed, a V-shaped high-voltage electric pulse is obtained. When HV is 1.6kV, the amplitude and frequency of T1 to T5 are 12V and 10kHz respectively, and R1 to R 10 is 100kΩ, Q1~Q 10 The model is 2N5551, C1~C5 are 3nF, C6~C 10 0.1μF, R 11 ~R 20 is 10Ω, L1 and L2 are 440nH and 16nH respectively, C 11 and C 12 It is 1pF, and the model of D1~D5 is IN4007.

[0070] Figure 12 Schematic diagram of the V-shaped high-voltage pulse waveform of the small-sized streak image converter tube of the present invention.

[0071] Specifically, when the output load R is 200Ω, the waveform of the V-shaped high-voltage pulse is shown in the figure. The rising and falling edge times are 0.33ns and 0.275ns respectively, the peak value is -4.186kV, and the average slopes of the rising and falling edges are 12.68kV / ns and 15.22kV / ns respectively.

[0072] Figure 13 and Figure 14 This is a schematic diagram showing the comparison of imaging offset and relative error when the deflection compensation technology is used to improve dynamic spatial distortion in the small-sized streak image converter tube of the present invention.

[0073] Specifically, based on the deflection compensation principle, Figure 1 The electric field conditions and Figure 12The dynamic spatial distortion comparison results obtained by using a V-shaped high-voltage pulse with deflection compensation technology and loading only the rising edge of a 12.68kV / ns pulse on the deflection plate, and loading only the rising edge of a 2.54kV / ns pulse (i.e., the difference between the rising and falling edges of the V-shaped pulse is 15.22-12.68kV / ns) are shown in the figure. It should be noted that when only a scanning pulse with a linear integrated scanning speed of 2.54kV / ns is loaded on the deflection plate, the deflection range is 5.15-6.92mm, and the maximum deflection difference is 1.77mm. Preferably, as Figure 13 As shown in the figure, when only the rising edge of the pulse is applied to the deflection plate, the deflection relative to the ideal imaging position in the 15mm off-axis region ranges from 6.01 to 8.15mm, with a maximum deflection difference of 2.14mm relative to the on-axis position. When only the falling edge of the pulse is applied to the compensation plate, the deflection range is reduced to 5.87 to 6.58mm, and the maximum deflection difference is also reduced to 0.71mm, significantly reducing the curvature of the fitted fringe image.

[0074] Furthermore, the relative error curve between the off-axis position and the on-axis deflection is as follows: Figure 14 As the off-axis distance increases to 15mm, the relative errors of the three cases are 12.09%, 35.61%, and 34.36%, respectively. The deflection compensation technology significantly improves the dynamic spatial distortion.

[0075] Figure 15 and Figure 16 They are respectively schematic diagrams showing a comparison of the dynamic spatial resolution and relative error of the small-sized streak image converter tube of the present invention using the deflection compensation technology to improve the dynamic spatial distortion results.

[0076] Specifically, the imaging distribution, dynamic spatial resolution curve and its relative error with the on-axis dynamic spatial resolution are as follows: Figure 15 and Figure 16As shown, the dynamic spatial resolution ranges of the three cases are 145.46~42.10lp / mm (difference of 103.36lp / mm), 145.44~36.07lp / mm (difference of 109.37lp / mm) and 152.10~41.09lp / mm (difference of 111.01lp / mm). Preferably, the maximum relative errors of the on-axis dynamic spatial resolution are 71.05%, 75.19% and 72.98% respectively. The deflection compensation technology is used to significantly improve the dynamic spatial resolution at the edge of the detection area. It should be noted that the analysis results show that compared with only loading the rising edge of the V-shaped pulse as the scanning pulse, the deflection compensation technology can effectively improve the dynamic spatial distortion and enhance the dynamic spatial resolution at the edge of the detection area. In deflection compensation technology, the rise and fall of the V-shaped high-voltage pulse are voltage superimposed from the starting point, and the slopes of the two are different, so the combined scanning slope is a dynamic value. Therefore, compared with only loading an ideal linear scanning pulse (that is, the difference between the rising and falling edges of the V-shaped pulse), this technology can also improve dynamic spatial distortion and enhance the dynamic spatial resolution uniformity within the detection area.

[0077] In summary, this invention utilizes the principles of deflection compensation technology, analyzes the causes of dynamic spatial distortion in streak image converters, and analyzes their impact on dynamic spatial resolution performance to design a small streak image converter model with a compensation plate structure. A high-voltage pulse generator is designed using a multi-stage Marx circuit and a two-stage LC high-pass filter. Based on deflection compensation technology, the rising and falling edges of the pulse are loaded onto the deflection plate and the compensation plate, respectively, to achieve improved dynamic spatial distortion. The research results show that overall dynamic spatial distortion and spatial resolution uniformity are significantly improved. The research conclusions provide a universal reference method for improving the dynamic spatial distortion and enhancing the spatial resolution uniformity of streak image converters, and offer a theoretical basis for the development of small streak image converters with improved spatial resolution performance.

[0078] The above embodiments are intended only to illustrate the technical concepts and features of the present invention. Their purpose is to enable those skilled in the art to understand the present invention and implement it accordingly. They are not intended to limit the scope of protection of the present invention. All equivalent variations and modifications within the scope of the claims of the present invention are intended to be covered by the claims of the present invention.

Claims

1. A deflection compensation system for improving dynamic spatial distortion of a small streak image converter tube, characterized by: The main body of the small streak image converter tube consists of an accelerating section (photocathode voltage -15kV, grid voltage -14.7kV), a focusing section (first focusing electrode voltage -14.2kV, second focusing electrode voltage -13.0kV), an anode (grounded), scanning deflection plates (axial width 18.2mm, entrance height 2mm, exit height 18.4mm, exit-to-screen distance 33mm), a compensation plate (axial width 13.8mm, entrance height 14mm, exit height 25.4mm, exit-to-screen distance 5mm), and a phosphor screen (voltage 3.4kV). The total tube length is 120mm. The V-type high voltage pulse generator is designed with Marx circuit and LC high pass filter. The Marx circuit includes: DC power supply HV = 1.6kV, trigger signal T1 ~ T5 amplitude 12V, frequency 10kHz; avalanche transistors Q1 ~ Q 10 Model 2N5551, avalanche diodes D1~D5 model IN4007; charging capacitors C1~C5=3nF, damping resistors R1~R 10 =100kΩ, current limiting resistor R 11 ~R 20 =10Ω. The LC high-pass filter includes: inductor L1 = 440nH, L2 = 16nH, capacitor C 11 =C 12 =1pF, load resistance R=200Ω. The resulting V-shaped high-voltage pulse output has a rising edge slope of 12.68kV / ns, a falling edge slope of 15.22kV / ns, a peak value of -4.186kV, a rising edge time of 0.33ns, and a falling edge time of 0.275ns. A dynamic compensation mechanism applies the rising edge of the pulse to the scanning deflection plates, and the falling edge to the compensation plates, forming a deflection compensation system. This system improves dynamic spatial distortion through off-axis electronically differentiated deflection compensation.

2. The deflection compensation system according to claim 1, wherein: The deflection sensitivity of the compensation plate is 0.302 mm / kV, which is obtained by fitting the static voltage loading experiment and satisfies the linear relationship between the compensation voltage and the deflection amount: y2=0.302x2-0.002 Where x2 is the compensation plate voltage and y2 is the electron deflection amount.

3. The deflection compensation system according to claim 1, characterized in that The dynamic spatial distortion effect is improved: The electronic offset range in the 15mm off-axis area was reduced from 6.01-8.15mm to 5.87-6.58mm; the relative on-axis maximum offset difference was reduced from 2.14mm to 0.71mm, and the relative error was reduced from 35.61% to 12.09%; the dynamic spatial resolution difference was reduced from 109.37lp / mm to 103.36lp / mm, and the relative on-axis maximum resolution error was reduced from 75.19% to 71.05%.

4. The deflection compensation system according to claim 1, characterized in that The time synchronization method: A dual-channel high-voltage pulse generator is used to time-share two V-shaped pulses. A nanosecond delay unit is used to coarsely adjust the pulse phase, and the transmission line length is fine-tuned to achieve picosecond synchronization, ensuring that the electrons reach the compensation plate and match the falling edge timing.

5. The deflection compensation system according to claim 1, wherein: The slope difference of the V-shaped pulse is 2.54 kV / ns (15.22 kV / ns-12.68 kV / ns), and the off-axis electron deflection timing difference is compensated by dynamically scanning the slope.

6. The deflection compensation system according to claim 1, characterized in that Versatility of the technology: There is no need to customize the cathode or phosphor screen curvature, it is compatible with different tube types, and avoids the problem of focal area extension caused by electron lens correction, maintaining high time resolution.

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