Electron beam current control method, circuit and control system

Abstract

The invention discloses an electron beam current control method, circuit and system, and the method comprises the steps: adjusting the electron beam current of an electron beam application device through controlling a current control circuit of a laser system and a front feedback amplification circuit of the laser system; the method comprises the following steps: acquiring a first relevant parameter of the electron beam current; controlling the current control circuit to adjust the electron beam current to fluctuate in a first range based on the first related parameter; and controlling the front feedback amplification circuit to adjust the electron beam current to fluctuate in a second range based on the first related parameter. According to the electron beam current control method provided by the embodiment of the invention, the electron beam current is sampled to obtain the first relevant parameter, and the laser system is adjusted through the first feedback control unit and the second feedback control unit based on the first relevant parameter, so that the laser driving electron beam can be corrected in time; and the stability and the accuracy of the laser driving electron beam are ensured.

Description

Technical Field

[0001] The invention belongs to the field of electron beam current control, and in particular relates to an electron beam current control method, circuit and control system. Background Art

[0002] Electron beams can be used directly in fields such as material analysis, welding, and tumor treatment, and can also generate X-rays through bremsstrahlung radiation for nondestructive testing and material analysis. Electron guns are electron beam sources. Mainstream thermal emission electron guns generally use external current to directly heat the cathode, or use wire-wound heater heat conduction to heat the emitter. In the above heating methods, there is a transverse magnetic field on the cathode surface that is perpendicular to the electron beam current direction. This transverse magnetic field will affect the direction of electron movement, resulting in poor beam quality, and cannot meet the product requirements of small focus, especially micro focus.

[0003] The method of using electron beam or laser to heat the cathode can effectively eliminate the magnetic field. Among them, the method of electron beam back heating the cathode requires additional devices such as the cathode, insulation structure or acceleration power supply, and the structure is relatively complex, while the method of using laser back heating the cathode is relatively simple. In the electron gun with laser heating cathode, the greater the laser power and the higher the cathode temperature, the greater the electron beam current intensity that the electron gun can emit.

[0004] During the use of electron beams, it is usually necessary to stabilize the electron beam current at a certain value. Currently, the laser output is mainly controlled by sampling the sampling resistor of the laser and feeding it back to the front feedback amplifier circuit. However, this method of controlling the stable output of the laser still has the following problems: Even if the laser power output of the laser is stable, the response of the laser output to the electron beam current is not linear, because as the working time increases, the laser output of the laser is affected by temperature drift and the aging of semiconductor devices, which will cause the electron beam current to be unstable; in addition, even if the laser power output of the laser is stable, the performance of the light-heating cathode itself will fluctuate with the influence of factors such as working time, pollution, and extraction electric field adjustment. Summary of the invention

[0005] The purpose of the embodiments of the present invention is to provide an electron beam current control method, circuit and control system to solve the problem in the prior art that the electron beam current of the electron beam application device is unstable and difficult to control when the laser back heats the cathode.

[0006] A first aspect of the present invention provides an electron beam current control method, which adjusts the electron beam current of an electron beam application device by controlling a current control circuit of a laser system and a forward feedback amplifier circuit of the laser system. The method includes: Acquiring a first related parameter of the electron beam current; Based on the first related parameter, controlling the current control circuit to adjust the electron beam current to fluctuate within a first range; The feedforward amplifier circuit is controlled based on the first related parameter to adjust the electron beam current to fluctuate within a second range.

[0007] Further, controlling the current control circuit to adjust the electron beam current to fluctuate within a first range based on the first related parameter includes: Controlling the current control circuit to adjust the laser power of the laser system based on the first related parameter to control the electron beam current to fluctuate within a first range; The controlling the forward feedback amplifier circuit to adjust the electron beam current to fluctuate within a second range based on the first related parameter comprises: Based on the first related parameter, the forward feedback amplifier circuit is controlled to adjust the laser power of the laser system to control the electron beam current to fluctuate within a second range; The laser power P and the electron beam current I e The following relations are satisfied: Among them, the electron beam is emitted by the cathode, T is the cathode temperature, is the cathode overflow work, is the Boltzmann constant, is the thermal radiation coefficient, is the blackbody radiation constant, is the equivalent heat radiation area of ​​the entire cathode based on the heating surface temperature, is the thermal conductivity, is the temperature coefficient of thermal conductivity, is a function of the equivalent area or equivalent length of the cathode insulation and support structure, is the cathode emission surface area, Take 120A / cm for the thermal emission constant 2 , C is the calibration coefficient.

[0008] Furthermore, the electron beam application device further comprises an emitter, the emitter is used to emit an electron beam to form an electron beam current, the first related parameter comprises a voltage parameter, and the first related parameter for obtaining the electron beam current comprises: The voltage parameter is obtained through a loop where the induced current generated in the circumferential direction of the electron beam current resides.

[0009] Furthermore, the electron beam application device further comprises a target, the electron beam bombards the target and causes the target to generate a target current, and the first related parameter for obtaining the electron beam current comprises: The voltage parameter is obtained through the loop where the target current is located.

[0010] Furthermore, a temperature parameter of the laser system is obtained, and the forward feedback amplifier circuit is controlled based on the temperature parameter to adjust the temperature of the laser in the laser system.

[0011] According to a second aspect of the present invention, an embodiment provides a control circuit for electron beam current, which is used to be connected to a current control circuit of a laser system and a forward feedback amplifier circuit of the laser system respectively to adjust the electron beam current of an electron beam application device, and the control circuit for electron beam current includes: A first sampling unit, used for acquiring a first relevant parameter of the electron beam current; A first feedback control unit, used to be connected to the first sampling unit and the current control circuit respectively, and to control the current control circuit to adjust the electron beam current to fluctuate within a first range based on the first related parameter; The second feedback control unit is used to be connected to the first sampling unit and the front feedback amplifier circuit respectively, and to control the front feedback amplifier circuit to adjust the electron beam current to fluctuate within a second range based on the first related parameter.

[0012] Further, the electron beam application device includes an emitter, the emitter is used to emit the electron beam, the first related parameter includes a voltage parameter, and the control circuit includes: The induction coil is used to be arranged on the circumference of the electron beam current loop to generate an induced current. The first sampling unit is respectively connected to the induction coil, the first feedback control unit and the second feedback control unit to obtain the voltage parameter through the loop where the induced current is located and feed the voltage parameter back to the first feedback control unit or the second feedback control unit.

[0013] Furthermore, the electron beam application device also includes a target, the electron beam bombards the target and causes the target to generate a target current, and the first sampling unit is respectively connected to the target, the first feedback control unit and the second feedback control unit to obtain the voltage parameter through the loop where the target current is located and feed back the voltage parameter to the first feedback control unit or the second feedback control unit.

[0014] Furthermore, the laser system further includes a power amplifier circuit, and the control circuit further includes: The second sampling unit is used to be connected to the power amplifier circuit and the second feedback control unit respectively to obtain a second related parameter, and adjust the first indicator of the laser system based on the second related parameter.

[0015] According to a third aspect of the present invention, an electron beam current control system is provided, comprising: Electron beam application device; A laser system, wherein the laser system has a current control circuit and a forward feedback amplifier circuit; The electron beam current control circuit described in the above embodiment.

[0016] According to the electron beam current control method of the embodiment of the present invention, by sampling the electron beam current to obtain the first relevant parameter, and adjusting the laser system respectively through the first feedback control unit and the second feedback control unit based on the first relevant parameter, it is possible to achieve timely correction of the long-term instability or short-term fluctuation of the laser-driven electron beam, thereby ensuring the accuracy and stability of the laser-driven electron beam. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a flow chart of an electron beam current control method according to an embodiment of the present invention; Figure 2 is a control principle diagram of a control circuit for electron beam current according to an embodiment of the present invention; Figure 3 is a schematic diagram of the electron beam current adjustment range according to an embodiment of the present invention; Figure 4 A physical principle diagram of laser heating cathode feedback according to an embodiment of the present invention; Figure 5 is a schematic diagram of the connection between the electron gun and the first sampling unit according to an embodiment of the present invention; Figure 6 FIG. 4 is another schematic diagram of the connection between the ray tube and the first sampling unit according to an embodiment of the present invention.

[0018] Reference numerals The electron beam current control circuit 100; the first sampling unit 110; the first feedback control unit 120; the second feedback control unit 130; the second sampling unit 140; Laser system 200; voltage reference 210; control panel 220; current limiting circuit 230; current control circuit 240; soft start circuit 250; forward feedback amplifier circuit 260; power amplifier circuit 270; semiconductor laser 280; Electron beam application device 300; emitter 310; insulating shell 320; induction coil 330; electron beam 340; target 350; High voltage power supply 400. DETAILED DESCRIPTION

[0019] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] The terms "first", "second", etc. in the specification and claims of the present invention are used to distinguish similar objects, and are not used to describe a specific order or sequence. It should be understood that the terms used in this way are interchangeable under appropriate circumstances, so that the embodiments of the present invention can be implemented in an order other than those illustrated or described herein. In addition, the term "and / or" in the specification and claims means at least one of the connected objects, and the character " / " generally indicates that the objects associated with each other are in an "or" relationship.

[0021] Combine the following Figures 1 to 6 , the electron beam current control method provided by the embodiment of the present invention is described in detail through specific embodiments and application scenarios.

[0022] In addition, the technical features involved in the different embodiments of the present application described below can be combined with each other as long as they do not conflict with each other.

[0023] According to the electron beam current control method of the embodiment of the present invention, the electron beam current of the electron beam application device 300 is adjusted by controlling the current control circuit 240 of the laser system 200 and the forward feedback amplifier circuit 260 of the laser system 200, such as Figure 1 and Figure 2 As shown, the method includes the following: S10, obtaining a first relevant parameter of the electron beam current; S20, controlling the current control circuit 240 to adjust the electron beam current to fluctuate within a first range based on the first related parameter; S30, controlling the forward feedback amplifier circuit 260 based on the first related parameter to adjust the electron beam current to fluctuate within the second range.

[0024] Specifically, the electron beam application device 300 can be an electron gun or a ray tube, and the electron beam current is the tube current generated by the electron beam 340. Due to the influence of the environment and the device itself, the output voltage of the semiconductor laser 280 (referred to as the laser) and the electron beam current emitted by its heated cathode (emitter 310) are not in an accurate linear correspondence. The traditional adjustment method of sampling and feeding back the forward feedback amplifier circuit 260 of the laser system 200 to adjust the laser output can achieve the adjustment of the laser output voltage and current, but it cannot adapt to the nonlinear fluctuation characteristics of the semiconductor laser 280 and the load itself, and cannot accurately control the laser-driven electron beam current. Therefore, the present application proposes a dual feedback control method for electron beam current.

[0025] The control method can be implemented by the electron beam current control circuit 100, such as Figure 2 As shown, the laser system 200 includes a voltage reference 210, a control panel 220, a current limiting circuit 230, a current control circuit 240, a soft start circuit 250, a front feedback amplifier circuit 260, a power amplifier circuit 270 and a semiconductor laser 280. Among them, the current limiting circuit 230 is connected to the voltage reference 210 and the current control circuit 240, the current control circuit 240 is connected to the control panel 220 and the soft start circuit 250, the soft start circuit 250 is connected to the front feedback amplifier circuit 260, the front feedback amplifier circuit 260 is connected to the power amplifier circuit 270, the power amplifier circuit 270 is connected to the semiconductor laser 280, and the semiconductor laser 280 is used to heat the cathode (emitter 310), and the electron beam 340 generated by the cathode bombards the target 350 after being accelerated by the high voltage power supply 400. The control circuit 100 of the electron beam current includes a first sampling unit 110, a first feedback control unit 120 and a second feedback control unit 130. The first sampling unit 110 is used to obtain a first related parameter of the electron beam current. The first feedback control unit 120 and the second feedback control unit 130 are respectively connected to the first sampling unit 110, and the first feedback control unit 120 is connected to the current control circuit 240, and the second feedback control unit 130 is connected to the front feedback amplifier circuit 260.

[0026] Specifically, the reference value I0 of the electron beam current and the voltage value of the high-voltage power supply 400 required to be obtained are set according to the factory data through the control panel 220, the current control circuit 240 outputs the reference value signal, the semiconductor laser 280 starts to work, the semiconductor laser 280 heats the emitter 310 and after preheating is completed, the high-voltage power supply 400 is started, and the cathode emits the electron beam 340 under the drive of the high voltage. At this time, the first relevant parameter of the electron beam current is obtained through the first sampling unit 110, and the first feedback control unit 120 adjusts the current control circuit 240 based on the first relevant parameter. The current control circuit 240 directly corrects the current reference value I0 by adjusting the output of the laser 280 to ensure that the electron beam current is adjusted from the reference value I0 to the set value I s A wider first range (I pp1 ) internal fluctuations, such as Figure 3 As shown, the horizontal axis is time and the vertical axis is current. For example, to ensure that the electron beam current is within the set value I s The current control circuit 240 is a primary setting, which can be adjusted by software and algorithms, and the adjustment speed is relatively slow.

[0027] When the electron beam current is within the first range, the semiconductor laser 280 can be in a normal working state. However, due to the performance fluctuation of the semiconductor laser 280 and the cathode, the nonlinear effect of the device, the fluctuation of the power supply and other factors, the electron beam current may fluctuate. At this time, based on the first related parameter, the second feedback control unit 130 adjusts the front feedback amplifier circuit 260, thereby fine-tuning the output of the semiconductor laser 280 to further correct the electron beam current within the set value I s A smaller area nearby (I pp2 ) to promptly respond to hardware performance fluctuations, reduce the amplitude of electron beam current fluctuations around the set value, and improve the stability of electron beam current. For example, ensure that the electron beam current is within the set value I s The feedback amplifier circuit 260 is a hardware at the back end. Once it is made according to the requirements, it cannot be changed. If it is not suitable, the only option is to replace the components.

[0028] That is to say, after the cathode preheating is completed, if Figure 2 and Figure 3As shown, the main feedback adjustment is performed by the first feedback control unit 120 during the time t1-t2, and the adjustment time is relatively long (s order of magnitude), and the secondary feedback adjustment is performed by the second feedback control unit 130 during the time t3-t4, and the adjustment time is relatively short (10ms order of magnitude). It should be noted that the first feedback control unit 120 and the second feedback control unit 130 are two independent feedback control units, and the first feedback control unit 120 and the second feedback control unit 130 can simultaneously feed back to their respective corresponding adjustment circuits according to the first related parameters, thereby adjusting the electron beam current respectively.

[0029] Therefore, according to the electron beam current control method of the embodiment of the present invention, by sampling the electron beam current to obtain the first relevant parameter, and adjusting the laser system 200 respectively through the first feedback control unit 120 and the second feedback control unit 130 based on the first relevant parameter, it is possible to achieve timely correction of the long-term instability or short-term fluctuation of the laser-driven electron beam 340, thereby ensuring the accuracy and stability of the laser-driven electron beam 340.

[0030] Furthermore, if Figure 4 As shown in the figure, the cathode temperature, gate control voltage, acceleration voltage and other parameters jointly determine the electron beam current emitted by the cathode. The relevant parameters of the electron beam current are detected by the sampling resistor. According to the difference between the current and the target value, the feedback adjustment method and step size are determined, and the laser control parameters are automatically adjusted. The laser power P (average power) is corrected to adjust the cathode temperature.

[0031] Specifically, the cathode saturation emission current I e for: Current I e The differential relationship with the cathode temperature T is: When the cathode works stably, it reaches thermal equilibrium and the input power P in And the output power P out Equivalent, output power P in For the conduction output P cdt and radiation output P rad sum. P in =P out =P cdt +P rad (3) The conducted output and radiated output powers are: P cdt =εσST 4 (4) P rad =K T G(TTR )=K0G(1+k K T)T (5) Therefore, the relationship between input power and temperature and their differential relationship are: P in =εσST 4 +K0G(1+k K T)T (6) Combining (2) and (7), the differential relationship model between the saturated emission current and the input laser power can be obtained as follows: In formulas (1) to (9), the electron beam is emitted by the cathode, T is the cathode temperature, φ is the cathode overflow work, k is the Boltzmann constant, ε is the thermal radiation coefficient, σ is the blackbody radiation constant (Stefan-Boltzmann constant), S is the equivalent thermal radiation area of ​​the entire cathode based on the heating surface temperature, K0 is the thermal conductivity, and k K is the temperature coefficient of thermal conductivity, G is the geometric characteristic, i.e., the function of the equivalent area or equivalent length of the cathode insulation and support structure, S c is the cathode emission surface area, A is the thermal emission constant, which is 120A / cm 2 , C is the calibration coefficient.

[0032] Formula (9) reflects the proportional relationship between the electron beam current and the laser power when the cathode is at temperature T. Based on this formula model, experimental fitting is performed for a specific electron gun structure to obtain a physically meaningful fitting numerical model for control feedback.

[0033] According to one embodiment of the present invention, the electron beam application device 300 also includes an emitter 310, which is used to emit an electron beam 340 to form an electron beam current. The first related parameter includes a voltage parameter. Obtaining the first related parameter of the electron beam current includes: obtaining the voltage parameter through a loop where the induced current generated in the circumferential direction of the electron beam current is located.

[0034] Specifically, Figure 5 As shown, the electron beam application device 300 may be an electron gun, such as Figure 6As shown, the electron beam application device 300 may also be a ray tube. The electron gun and the ray tube respectively include structures such as an emitter 310 and an insulating shell 320. A vacuum chamber is defined in the insulating shell 320. The emitter 310 emits an electron beam 340 in the vacuum chamber. An induction coil 330 is sleeved on the periphery of the electron gun or the ray tube, or an induction coil 330 is sleeved on a specific circuit loop structure of the electron beam current. The induced current generated in the induction coil 330 is in direct proportion to the electron beam current. The first sampling unit 110 is connected to the loop where the induced current is located to obtain a voltage parameter. The first sampling unit 110 feeds back the voltage parameter to the first feedback control unit 120 or the second feedback control unit 130. The first feedback control unit 120 or the second feedback control unit 130 adjusts the electron beam current according to the voltage parameter.

[0035] Furthermore, when the electron beam application device 300 is a ray tube, Figure 6 As shown, the ray tube further includes a target 350. The electron beam bombards the target 350 and causes the target 350 to generate a target current. Acquiring the first relevant parameter of the electron beam current includes: acquiring a voltage parameter through a loop where the target current is located.

[0036] In other words, in addition to obtaining voltage parameters by means of induction current, the ray tube can also obtain voltage parameters by means of target current. Specifically, the first sampling unit 110 is connected to the loop where the target current is located, wherein the target current is equivalent to the electron beam current, and the first sampling unit 110 adjusts and controls the electron beam current by obtaining voltage parameters and feeding them back to the first feedback control unit 120 and the second feedback control unit 130. The first sampling unit 110 may include a sampling load and a specific voltage sampling device or circuit.

[0037] That is to say, there are two ways to obtain the electron beam current voltage parameters through the first sampling unit 110. One is for the electron gun, by performing voltage sampling on the induced current formed by the electron beam current emitted by the electron gun; the other is for the ray tube, by performing voltage sampling on the target current generated by the electron beam bombarding the target 350, and by performing voltage sampling on the induced current generated by the electron beam current.

[0038] In one embodiment of the present invention, the electron beam current control method further includes: acquiring a temperature parameter of the laser system 200 , and adjusting the temperature of the laser in the laser system 200 based on the temperature parameter.

[0039] In other words, the laser system 200 also includes a power amplifier circuit 270, and the electron beam current control circuit 100 also includes a second sampling unit 140. The second sampling unit 140 can also be a sampling unit of the laser system 200. The second sampling unit 140 is connected to the power amplifier circuit 270 and the second feedback control unit 130 respectively to obtain the temperature parameters inside the laser and convert the temperature parameters into a voltage signal. The second feedback control unit 130 controls the front feedback amplifier circuit 260 based on the voltage signal to adjust the temperature inside the laser to ensure that the laser can operate within a normal temperature range.

[0040] In addition, the second sampling unit 140 may also be used to obtain other parameters of the laser system 200 to adjust other indicators of the laser system 200 to meet the working conditions of the laser system 200 .

[0041] The electron beam current control circuit 100 according to the second aspect of the present invention is used to be connected to the current control circuit 240 of the laser system 200 and the front feedback amplifier circuit 260 of the laser system 200, respectively, and the electron beam current control circuit 100 includes a first sampling unit 110, a first feedback control unit 120 and a second feedback control unit 130. The electron beam current control circuit 100 according to the embodiment of the present invention can work based on the electron beam current control method described in the above embodiment.

[0042] Specifically, the first sampling unit 110 is used to obtain the first relevant parameters of the electron beam current, the first feedback control unit 120 is used to be connected to the first sampling unit 110 and the current control circuit 240 respectively, and to control the current control circuit 240 to adjust the electron beam current to fluctuate within the first range based on the first relevant parameters, and the second feedback control unit 130 is used to be connected to the first sampling unit 110 and the front feedback amplifier circuit 260 respectively, and to control the front feedback amplifier circuit 260 to adjust the electron beam current to fluctuate within the second range based on the first relevant parameters.

[0043] That is to say, Figure 2As shown, the laser system 200 includes a voltage reference 210, a control panel 220, a current limiting circuit 230, a current control circuit 240, a soft start circuit 250, a front feedback amplifier circuit 260, a power amplifier circuit 270 and a semiconductor laser 280. Among them, the current limiting circuit 230 is connected to the voltage reference 210 and the current control circuit 240, the current control circuit 240 is connected to the control panel 220 and the soft start circuit 250, the soft start circuit 250 is connected to the front feedback amplifier circuit 260, the front feedback amplifier circuit 260 is connected to the power amplifier circuit 270, the power amplifier circuit 270 is connected to the semiconductor laser 280, the semiconductor laser 280 is used to heat the emitter 280, and the electron beam 340 generated by the cathode (i.e., the emitter 280) bombards the target 350 after being accelerated by the high voltage power supply 400. The control circuit 100 of the electron beam current includes a first sampling unit 110, a first feedback control unit 120 and a second feedback control unit 130. The first sampling unit 110 is used to obtain a first related parameter of the electron beam current. The first feedback control unit 120 and the second feedback control unit 130 are respectively connected to the first sampling unit 110, and the first feedback control unit 120 is connected to the current control circuit 240, and the second feedback control unit 130 is connected to the front feedback amplifier circuit 260.

[0044] Specifically, the reference value I0 of the electron beam current and the voltage value of the high-voltage power supply required to be obtained are set through the control panel 220 according to the factory data, the current control circuit 240 outputs the reference value signal, the semiconductor laser 280 starts to work, the semiconductor laser 280 heats the cathode and completes the preheating, and then starts the high-voltage power supply 400, and the cathode emits an electron beam 340 under the drive of the high voltage. At this time, the first relevant parameter of the electron beam current is obtained through the first sampling unit 110, and the first feedback control unit 120 adjusts the current control circuit 240 based on the first relevant parameter. The current control circuit 240 directly corrects the current reference value I0 by adjusting the output of the laser 280 to ensure that the electron beam current is adjusted from the reference value I0 to the set value I s A wider first range (I pp1 ), for example, to ensure that the electron beam current is within the set value I s Fluctuates within a range of one thousandth.

[0045] When the electron beam current is within the first range, the semiconductor laser 280 can be in a normal working state. However, due to the performance fluctuation of the laser system 200 and the cathode, the nonlinear effect of the device, the fluctuation of the power supply and other factors, the electron beam current may fluctuate. At this time, based on the first related parameter, the second feedback control unit 130 adjusts the front feedback amplifier circuit 260, thereby fine-tuning the output of the semiconductor laser 280 to further correct the electron beam current within the set value I s A smaller area nearby (I pp2) to promptly respond to hardware performance fluctuations and reduce the amplitude of electron beam current fluctuations around the set value. For example, ensure that the electron beam current is within the set value I s It fluctuates within a range of one ten-thousandth.

[0046] That is to say, after the cathode preheating is completed, if Figure 2 and Figure 3 As shown, the main feedback adjustment is performed by the first feedback control unit 120 during the time t1-t2, and the adjustment time is relatively long (s order of magnitude), and the secondary feedback adjustment is performed by the second feedback control unit 130 during the time t3-t4, and the adjustment time is relatively short (10ms order of magnitude). It should be noted that the first feedback control unit 120 and the second feedback control unit 130 are two independent feedback control units, and the first feedback control unit 120 and the second feedback control unit 130 can simultaneously feed back to their respective corresponding adjustment circuits according to the first related parameters, thereby adjusting the electron beam current respectively.

[0047] Therefore, the electron beam current control circuit 100 according to the embodiment of the present invention can achieve timely correction of long-term instability or short-term fluctuation of the laser-driven electron beam 340 by sampling the electron beam current to obtain the first relevant parameter, and adjusting the laser system 200 through the first feedback control unit 120 and the second feedback control unit 130 based on the first relevant parameter, thereby ensuring the accuracy and stability of the laser-driven electron beam 340.

[0048] Preferably, the electron beam application device 300 includes an emitter 310, which is used to emit an electron beam 340. The first related parameter includes a voltage parameter. The control circuit 100 of the electron beam current includes: an induction coil 330, which is used to be arranged in the circumferential direction of the electron beam current loop to generate an induced current. The first sampling unit 110 is respectively connected to the induction coil 330, the first feedback control unit 120 and the second feedback control unit 130 to obtain the voltage parameter through the induced current and feed the voltage parameter back to the first feedback control unit 120 or the second feedback control unit 130.

[0049] That is to say, when the electron beam application device 300 is an electron gun or a ray tube, voltage sampling can be performed through the induced current generated by the electron beam current. The electron beam current and the induced current are in direct proportion. The voltage parameters are fed back to the first feedback control unit 120 and the second feedback control unit 130 through the first sampling unit 110, so that the electron beam current can be regulated and controlled, wherein the first sampling unit 120 may include a sampling load and a specific voltage sampling device or circuit.

[0050] Optionally, the electron beam application device 300 also includes a target 350, the electron beam 340 bombards the target 350 and causes the target 350 to generate a target current, and the first sampling unit 110 is respectively connected to the target 350, the first feedback control unit 120 and the second feedback control unit 130 to obtain voltage parameters through the target current and feed the voltage parameters back to the first feedback control unit 120 or the second feedback control unit 130.

[0051] In other words, when the electron beam application device 340 is a ray tube, Figure 6 As shown, voltage sampling can also be performed through the target current, and the first sampling unit 110 feeds back the voltage parameter to the first feedback control unit 120 and the second feedback control unit 130 to achieve control of the electron beam current.

[0052] The load-based second feedback control unit 130 reflects the nonlinear physical model of the entire process from electron beam current sampling to semiconductor laser 280 adjustment, embodies the overall performance of the hardware series connection, omits the measurement and feedback hardware of parameters such as optical power, light spot, cathode temperature, cathode emission performance, etc., and reduces the complexity and cost of the feedback process.

[0053] According to one embodiment of the present invention, the laser system 200 further includes a power amplifier circuit 270, and the electron beam current control circuit 100 further includes a second sampling unit 140, and the second sampling unit 140 is used to be connected to the power amplifier circuit 270 and the second feedback control unit 130 respectively to obtain a second related parameter of the laser system 200, and the second feedback control unit 130 adjusts the first index of the laser system 200 based on the second related parameter. Among them, the second related parameter can be a temperature parameter, and the first index can be the temperature inside the laser. By adjusting the temperature inside the laser, the normal working environment of the laser system 200 is guaranteed. In addition, the second sampling unit 140 can also be used to obtain other parameters of the laser system 200 to adjust other indicators of the laser system 200, for example, to adjust the working current of the laser system 200 itself, so as to meet the normal working conditions of the laser system 200.

[0054] The electron beam current control system according to the third aspect of the present invention comprises an electron beam application device 300, a laser system 200 and the electron beam current control circuit 100 in the above embodiment, wherein the laser system 200 comprises a current control circuit 240 and a forward feedback amplifier circuit 260.

[0055] Since the electron beam current control circuit 100 according to the embodiment of the present invention has the beneficial effect of ensuring the accuracy and stability of the laser-driven electron beam 340, the electron beam current control system according to the embodiment of the present invention also has the beneficial effect of ensuring the accuracy and stability of the laser-driven electron beam 340.

[0056] Other structures and operations of the electron beam current control system are known to those skilled in the art and will not be described in detail here.

[0057] The embodiments of the present invention are described above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned specific implementation modes, which are merely illustrative rather than restrictive. Under the guidance of the present invention, ordinary technicians in this field can also make many forms without departing from the scope of protection of the present invention and the claims, all of which are within the protection of the present invention.

Claims

1. A method for controlling electron beam current, characterized in that: The method comprises: adjusting the electron beam current of the electron beam application device by controlling the current control circuit of the laser system and the forward feedback amplifier circuit of the laser system. Acquiring a first related parameter of the electron beam current; Based on the first related parameter, controlling the current control circuit to adjust the electron beam current to fluctuate within a first range; The feedforward amplifier circuit is controlled based on the first related parameter to adjust the electron beam current to fluctuate within a second range.

2. The electron beam current control method according to claim 1, characterized in that: The controlling the current control circuit to adjust the electron beam current to fluctuate within a first range based on the first related parameter comprises: Controlling the current control circuit to adjust the laser power of the laser system based on the first related parameter to control the electron beam current to fluctuate within a first range; The controlling the forward feedback amplifier circuit to adjust the electron beam current to fluctuate within a second range based on the first related parameter comprises: Based on the first related parameter, the forward feedback amplifier circuit is controlled to adjust the laser power of the laser system to control the electron beam current to fluctuate within a second range; The laser power P and the electron beam current I e The following relations are satisfied: Among them, the electron beam is emitted by the cathode, T is the cathode temperature, is the cathode overflow work, is the Boltzmann constant, is the thermal radiation coefficient, is the blackbody radiation constant, is the equivalent heat radiation area of ​​the entire cathode based on the heating surface temperature, is the thermal conductivity, is the temperature coefficient of thermal conductivity, is a function of the equivalent area or equivalent length of the cathode insulation and support structure, is the cathode emission surface area, Take 120A / cm for the thermal emission constant 2 , C is the calibration coefficient.

3. The electron beam current control method according to claim 1, wherein the electron beam application device further comprises an emitter, wherein the emitter is used to emit an electron beam to form an electron beam current, wherein: The first related parameter includes a voltage parameter, and the first related parameter for obtaining the electron beam current includes: The voltage parameter is obtained through a loop where the induced current generated in the circumferential direction of the electron beam current resides.

4. The electron beam current control method according to claim 3, wherein the electron beam application device further comprises a target, and the electron beam bombards the target to cause the target to generate a target current, wherein: The obtaining of the first related parameter of the electron beam current comprises: The voltage parameter is obtained through the loop where the target current is located.

5. The electron beam current control method according to claim 3 or 4, characterized in that: The temperature parameter of the laser system is acquired, and the forward feedback amplifier circuit is controlled based on the temperature parameter to adjust the temperature of the laser in the laser system.

6. A control circuit for electron beam current, characterized in that: The control circuit is used to be connected to the current control circuit of the laser system and the forward feedback amplifier circuit of the laser system respectively to adjust the electron beam current of the electron beam application device, and the control circuit of the electron beam current includes: A first sampling unit, used for acquiring a first relevant parameter of the electron beam current; A first feedback control unit, used to be connected to the first sampling unit and the current control circuit respectively, and to control the current control circuit to adjust the electron beam current to fluctuate within a first range based on the first related parameter; The second feedback control unit is used to be connected to the first sampling unit and the front feedback amplifier circuit respectively, and to control the front feedback amplifier circuit to adjust the electron beam current to fluctuate within a second range based on the first related parameter.

7. The electron beam current control circuit according to claim 6, wherein the electron beam application device comprises an emitter, and the emitter is used to emit the electron beam, characterized in that: The first related parameter includes a voltage parameter, and the control circuit includes: The induction coil is used to be arranged on the circumference of the electron beam current loop to generate an induced current. The first sampling unit is respectively connected to the induction coil, the first feedback control unit and the second feedback control unit to obtain the voltage parameter through the loop where the induced current is located and feed the voltage parameter back to the first feedback control unit or the second feedback control unit.

8. The electron beam current control circuit according to claim 7, wherein the electron beam application device further comprises a target, and the electron beam bombards the target to cause the target to generate a target current, wherein: The first sampling unit is connected to the target, the first feedback control unit and the second feedback control unit respectively, so as to obtain the voltage parameter through the loop where the target current is located and feed the voltage parameter back to the first feedback control unit or the second feedback control unit.

9. The electron beam current control circuit according to claim 8, characterized in that: The laser system further includes a power amplifier circuit, and the control circuit further includes: The second sampling unit is used to be connected to the power amplifier circuit and the second feedback control unit respectively to obtain a second related parameter, and adjust the first indicator of the laser system based on the second related parameter.

10. An electron beam current control system, characterized in that: include: Electron beam application device; A laser system, wherein the laser system has a current control circuit and a forward feedback amplifier circuit; The electron beam current control circuit according to any one of claims 6 to 9.

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