CN207149522U - The control circuit of small-sized on-radiation electron source with fast-pulse mode of operation - Google Patents

Abstract

It the utility model is related to vacuum electronics technology field and high voltage circuit field,The control circuit of small-sized on-radiation electron source with fast-pulse mode of operation,The filament controller in filament heating current source,Current inductor I,Voltage sensor I is all connected with microprocessor respectively,And voltage sensor I connection filaments,Microprocessor difference output reference voltage I,Control source port I and control source port II in reference voltage II to grid voltage impulse generator,And input voltage amplifier,Current inductor II,Voltage sensor II is all connected with microprocessor respectively,And voltage sensor II connects the compensation amplifying circuit for extracting grid and impulse compensation amplifier simultaneously,Compensate amplifying circuit connection emission current measurement module,And the offset voltage connection microprocessor of compensation amplifier,The compensation control circuit of emission current measurement module,Integrating circuit is all connected with microprocessor respectively,Emission current measurement module input is sequentially connected high-voltage power supply,Insulating power supply.

Description

The control circuit of small-sized on-radiation electron source with fast-pulse mode of operation

Technical field

Vacuum electronics technology field and high voltage circuit field are the utility model is related to, especially a kind of simple structure is effective The small-sized on-radiation electron source with fast-pulse mode of operation control circuit.

Background technology

Existing on-radiation electron source defect is, first, focusing system volume is big, second, the method for pulsed electron transmitting, Electronic beam current is complete blank between two ionization pulses, and emission current only measures within the time of ionization pulse. But in some applications such as ionic migration spectrometer, ionization times can be short to 1 microsecond, and electronic current is less than 1nA, is Direct measurement this current impulse, transimpedance amplifier need the bandwidth more than 1MHz, and noise current is in below 100pA.On The hardly possible realization of such condition is stated, prior art is to measure one using a relatively slow current amplifier Fix time the average value of interior emission current, by known dutycycle, the emission current during actual transmission can be calculated. But the duration can be smaller by 10000 than the emission current of reality in 10ms magnitudes, average emitted electric current in ion mobility spectrometry Times, which results in the decline of signal to noise ratio, and a slower control system is needed, it is extremely slow to further cause system response. The control circuit of the small-sized on-radiation electron source with fast-pulse mode of operation can solve this problem.

Utility model content

In order to solve the above problems, the utility model provides a kind of electricity of the Highgrade integration using only single control grid Component, device are mainly a small-sized glass tube with vacuum, and its supply lead and metal electrode for including, simple structure have Effect.

Technical scheme is used by the utility model：

The control circuit of the small-sized on-radiation electron source with fast-pulse mode of operation mainly includes accelerating electricity Potential source, ammeter, the filament heating current for extracting voltage source, being made up of filament controller, current inductor I, voltage sensor I Source, filament, extract grid, silicon nitride film, glass tube with vacuum, by control source port I, control source port II, voltage source, light Fine I, voltage amplifier, current inductor II, grid voltage impulse generator, microprocessor, the COM of voltage sensor II compositions Module, computer, the impulse compensation amplifier being made up of offset voltage, compensation amplifying circuit, put by compensation control circuit, electric current The isolation electricity of big device, the high-voltage power supply of the emission current measurement module of integrating circuit composition including rectifier I including rectifier II Source and optical fiber II, the compensation amplifying circuit include a differential amplifier circuit, and the integrating circuit includes one 16 Position diclinic rate digital analog converter, the bleeding point of glass tube with vacuum is sealing, and the filament of tungsten material is located at glass tube with vacuum Interior one end, thermoelectron is produced after electrified regulation, and the extraction grid is located at before the filament in glass tube with vacuum and can Thermal electron stream is controlled by changing the field strength of filament surface, the glass tube with vacuum other end, which is provided with made of a copper, to be added Fast electrode and its center have the hole of 1 millimeter of a diameter, and the silicon nitride film of the Kong Youyi 250 nanometer thickness seals, Electron source inside is vacuum environment, outside is atmospheric environment, and electronics of the kinetic energy more than 7keV can pass through the silicon nitride film, institute It is all -10kV to state filament and extract grid relative to the potential of acceleration electrode, and the electric field as caused by electrical potential difference makes the electronics of transmitting Accelerate to kinetic energy 10keV, can enter atmospheric environment through the silicon nitride film, have in the glass tube with vacuum getter with Vacuum environment can be kept.

In the control circuit, filament controller, current inductor I, the voltage sensor in the filament heating current source I is all connected with microprocessor and the voltage sensor I connections filament respectively, and the microprocessor exports with reference to electricity respectively I, control source port I and control source port II in reference voltage II to the grid voltage impulse generator are pressed, and it is defeated Enter voltage amplifier, the current inductor II, voltage sensor II are all connected with microprocessor and the voltage sensor respectively II connects the compensation amplifying circuit of the extraction grid and the impulse compensation amplifier, the compensation amplifying circuit connection simultaneously The offset voltage of the emission current measurement module and the impulse compensation amplifier connects microprocessor, the emission current Compensation control circuit, the integrating circuit of measurement module are all connected with microprocessor and integrating circuit connection optical fiber II, institute respectively State emission current measurement module input and be sequentially connected high-voltage power supply, insulating power supply, the microprocessor is connected by COM modules and counted Calculation machine.

It is the consideration based on following effects that the utility model, which produces pulse method, that is, controls the voltage of the extraction grid Realize, be easy to and quickly switch in order that the voltage can be realized, completed by designing suitable circuit have Body, the method for producing pulse is that the decay factor is by switching between two voltages with the differential declines factor The ratio between external emission electronic current and internal emission electronic current of electron source, one of voltage cause part to focus on electronics and arrive On the silicon nitride film, another voltage defocuses electron beam completely, reaches silicon nitride film without electronics, then external emission electric current In opening and closing, the two states switch over can, can because decay factor is constant for some specific voltage It is readily available with the measurement by static state.

Because no matter external emission electric current is in unlatching or closed mode or during switching, internal emission electricity Stream keeps constant, and continuously it can be measured, and can be controlled it by adjusting heater current；Also be exactly because Electron source for the present invention can continuously measure internal emission electric current, combined with increased internal emission electric current, realize ion The raising of signal to noise ratio in migration spectrum, therefore, external emission electric current can either be accurately controlled, and can is enough within the very short time A repeatable afterbody emission current is obtained, or even in low-down value.

Insulating power supply is the electronic component power supply for working in high potential；High-voltage power supply is the power supply for producing accelerating potential ,- Adjustable between 3kV to -15kV, the stability of this voltage is most important for current measurement；It is described by compensation control circuit, The emission current measurement module of current amplifier, integrating circuit composition, it, which is inputted, terminates the high-voltage power supply, and this is high-voltage power supply and its Uniquely coupled between his circuit, the ground of high-tension circuit is consistent with the potential of high-voltage power supply, so, it is any from high-voltage potential to The electric current on ground can all pass through the current amplifier, add so as to which current amplifier measures to be emitted by the filament and reached The electronic current of fast electrode, i.e. internal emission electric current.The electronic current flowed back to by the extraction grid is not measured, because The emission current measurement module only forms loop in high-tension circuit.Advantage is：In the measurement of less internal emission electric current In, relatively large grid electric current will not cause skew, and still, current amplifier circuit must have complete guarantor to overload current Shield, overload current are possible to produce in fault and normal opening process；The output signal quilt of the current amplifier Enter the microcontroller after one sixteen bit diclinic rate digital analog converter digitlization, a resistance is the resistant series of 1G ohms In the input of current amplifier, its effect is so that the input signal of diclinic rate digital analog converter always remains at its scope Center, so, regardless of the size of emission current and leakage current, electric current of the diclinic rate digital analog converter in both direction Transition has the reservation of maximum.In addition, the constant conversion time of diclinic rate digital analog converter greatly simplifies digitial controller Work, using this measurement apparatus, the resolution ratio of internal emission electric current is about 400fA, corresponding external emission electric current point Resolution is about 20fA.Filament heating current source is the controllable current source of a voltage, and the temperature coefficient of the resistance of tungsten filament is just Number, when temperature is relatively low, if with voltage fed, can cause a high inrush current, cause device damage, so will Use current source；The grid voltage impulse generator effect is the voltage of switching control grid, and electricity is opened and closed to reach The purpose of son transmitting, big voltage range is obtained by bipolar current source, changes the voltage of control grid using power supply feedback, When providing positive and negative 250V, any two voltage of the voltage of control grid in several microseconds between positive and negative 240V can be caused Switch between value；The impulse compensation amplifier effect is to compensate the extraction grid in current measurement to add pulse voltage process In due to Capacitance Coupled caused error.

The reason in view of safety and electromagnetic compatibility, all connections are all using shielding between control circuit and electron source High-voltage line, because the screen layer of high-voltage line is ground connection, therefore an obvious electricity can be produced between the extraction grid and ground Hold, and parasitic capacitance existing for script can be increased, as a result, applying pulse to the extraction grid can cause have electric current Ground is flowed to from above-mentioned electric capacity, cocurrent crosses high-voltage power supply, and the electric current can make rectified current measurement overload, the control of resultant interference emission current Circuit, in order that the influence of this electric current minimizes, add a compensation amplifier and can solve the problem that problem.Due to the electric capacity of cable Depending on the length of cable, different parasitic capacitances can be presented in different thermionic emitters devices in addition, and it is therefore necessary to change Become the gain of compensation amplifier, using two NPN transistors, connect into difference amplifier, the transmitting electricity of the difference amplifier Stream and gain can be adjusted by the microcontroller.

The beneficial effects of the utility model are：

The utility model is a kind of small low-cost electronic emitter with fast-pulse, while it is suitable to propose one kind Control circuit, it utilizes a single control grid, and the potential of grid only needs 10V difference, can make electron beam portion Divide and focus on or defocus；Only when Electron Beam Focusing, electronics emits from source, and the electronic current in source can be surveyed continuously Amount, it is of the invention compared with general commercial electronic emitter, hence it is evident that to have and simplify structure, improve to the excellent of emission current control Gesture.

Brief description of the drawings

Further illustrated with reference to figure of the present utility model：

Fig. 1 is non-radioactive electron source schematic diagram；

Fig. 2 is the control circuit schematic diagram of electron source.

In figure, 1. acceleration voltage sources, 2. ammeters, 3. extract voltage source, 4. filament heating current sources, the control of 4-1. filaments Device, 4-2. current inductors I, 4-3. voltage sensor I, 5. filaments, 6. extraction grids, 7. silicon nitride films, 8. glass tube with vacuums, 9. grid voltage impulse generator, 9-1. control sources port I, 9-2. control sources port II, 9-3. voltage sources, 9-4. optical fiber I, 9-5. voltage amplifier, 9-6. current inductors II, 9-7. voltage sensor II, 10. microprocessors, 11.COM modules, 12. computer, 13. impulse compensation amplifiers, 13-1. offset voltages, 13-2. compensation amplifying circuits, 14, emission current measurement mould Block, 14-1. compensation control circuits, 14-2. current amplifiers, 14-3. integrating circuit, 15. high-voltage power supplies, 15-1. rectifier I, 16. insulating power supply, 16-1. rectifiers II, 17. optical fiber II.

Embodiment

If Fig. 1 is non-radioactive electron source schematic diagram, if Fig. 2 is the control circuit schematic diagram of electron source, at work, electricity The control circuit of component will provide accelerating potential, filament heating current, control grid voltage, and measure emission current.

The control circuit of the small-sized on-radiation electron source with fast-pulse mode of operation mainly includes accelerating electricity Potential source 1, ammeter 2, extract voltage source 3, be made up of filament controller 4-1, current inductor I4-2, voltage sensor I4-3 Filament heating current source 4, filament 5, extract grid 6, silicon nitride film 7, glass tube with vacuum 8, by control source port I 9-1, Control source port II9-2, voltage source 9-3, optical fiber I9-4, voltage amplifier 9-5, current inductor II9-6, voltage sensor II9-7 composition grid voltage impulse generator 9, microprocessor 10, COM modules 11, computer 12, by offset voltage 13-1, Compensate the impulse compensation amplifier 13 of amplifying circuit 13-2 compositions, by compensation control circuit 14-1, current amplifier 14-2, integration The high-voltage power supply 15 of the emission current measurement module 14 including rectifier I15-1 of circuit 14-3 compositions including rectifier II16-1's Insulating power supply 16 and optical fiber II17, the compensation amplifying circuit 13-2 include a differential amplifier circuit, the integrating circuit 14-3 includes a sixteen bit diclinic rate digital analog converter, and the bleeding point of glass tube with vacuum 8 is sealing, tungsten material it is described Filament 5 is located at one end in glass tube with vacuum 8, and thermoelectron is produced after electrified regulation, and the extraction grid 6 is located at glass tube with vacuum 8 Before the interior filament 5 and thermal electron stream, glass tube with vacuum 8 can be controlled by changing the field strength of filament surface The other end is provided with acceleration electrode made of a copper and its center has the hole of 1 millimeter of a diameter, and the Kong Youyi opens 250 The silicon nitride film 7 of nanometer thickness seals, and electron source inside is vacuum environment, outside is atmospheric environment, and kinetic energy is more than 7keV's Electronics can pass through the silicon nitride film 7, the filament 5 and to extract grid 6 relative to the potential of electrode is accelerated all be -10kV, The electric field as caused by electrical potential difference makes the electronics of transmitting accelerate to kinetic energy 10keV, the silicon nitride film 7 can be passed through to enter big compression ring Border, the glass tube with vacuum 8 is interior, and there is getter can keep vacuum environment.

In the control circuit, filament controller 4-1, current inductor I4-2, the voltage in the filament heating current source 4 Inductor I4-3 is all connected with microprocessor 10 and the voltage sensor I4-3 connections filament 5, the microprocessor respectively Control source port I 9-1 in 10 difference output reference voltage I, reference voltage II to the grid voltage impulse generator 9 With control source port II9-2, and input voltage amplifier 9-5, the current inductor II9-6, voltage sensor II9-7 Microprocessor 10 is all connected with respectively and the voltage sensor II9-7 while connects the extraction grid 6 and impulse compensation The compensation amplifying circuit 13-2 of amplifier 13, the compensation amplifying circuit 13-2 connections emission current measurement module 14 and The offset voltage 13-1 connections microprocessor 10 of the impulse compensation amplifier 13, the compensation of the emission current measurement module 14 Control circuit 14-1, integrating circuit 14-3 are all connected with microprocessor 10 and the integrating circuit 14-3 connection optical fiber II respectively 17, the input of emission current measurement module 14 is sequentially connected high-voltage power supply 15, insulating power supply 16, and the microprocessor 10 passes through COM modules 11 connect computer 12.

It is the consideration based on following effects that the utility model, which produces pulse method, that is, controls the voltage of the extraction grid 6 To realize, it is easy to and quickly switches in order that the voltage can be realized, is completed by designing suitable circuit, Specifically, the method for producing pulse is the decay factor by switching between two voltages with the differential declines factor That is the ratio between the external emission electronic current of electron source and internal emission electronic current, one of voltage cause part to focus on electronics Onto the silicon nitride film 7, another voltage defocuses electron beam completely, reaches silicon nitride film without electronics, then external emission In opening and closing, the two states switch over electric current can, because decay factor is normal for some specific voltage Number, it can be readily available by the measurement of static state.

Because no matter external emission electric current is in unlatching or closed mode or during switching, internal emission electricity Stream keeps constant, and continuously it can be measured, and can be controlled it by adjusting heater current；Also be exactly because Electron source for the present invention can continuously measure internal emission electric current, combined with increased internal emission electric current, realize ion The raising of signal to noise ratio in migration spectrum, therefore, external emission electric current can either be accurately controlled, and can is enough within the very short time A repeatable afterbody emission current is obtained, or even in low-down value.

The insulating power supply 16 is the electronic component power supply for working in high potential；The high-voltage power supply 15 is to produce accelerating potential Power supply, -3kV arrive -15kV between it is adjustable, the stability of this voltage is most important for current measurement；It is described by compensating Control circuit 14-1, current amplifier 14-2, the emission current measurement module 14 of integrating circuit 14-3 compositions, it inputs termination institute High-voltage power supply 15 is stated, this is uniquely coupled between the high-voltage power supply 15 and other circuits, the ground of high-tension circuit and the high-voltage power supply 15 potential is consistent, and so, any electric current from high-voltage potential to ground can all pass through the current amplifier 14-2, so as to Current amplifier 14-2 measures the electronic current for being emitted by the filament 5 and being reached and accelerate electrode, i.e. internal emission electricity Stream.The electronic current flowed back to by the extraction grid 6 is not measured, because the emission current measurement module 14 is only in height Loop is formed in volt circuit.Advantage is：In the measurement of less internal emission electric current, relatively large grid electric current will not draw Skew is played, still, current amplifier 14-2 circuits there must be complete protection to overload current, and overload current is possible in circuit event Produced in barrier and normal opening process；The output signal of the current amplifier is by a sixteen bit diclinic rate digital analog converter Entering the microcontroller after digitlization, a resistance is the input of the resistant series in current amplifier 14-2 of 1G ohms, Its effect is so that the input signal of diclinic rate digital analog converter always remains at the center of its scope, so, no matter hair How is the size of radio stream and leakage current, and diclinic rate digital analog converter has the reservation of maximum in the current transients of both direction. In addition, the constant conversion time of diclinic rate digital analog converter greatly simplifies the work of digitial controller, this measurement is used Device, the resolution ratio of internal emission electric current is about 400fA, and the resolution ratio of corresponding external emission electric current is about 20fA.Filament adds Thermocurrent source is the controllable current source of a voltage, and the temperature coefficient of the resistance of tungsten filament is positive number, when temperature is relatively low, if With voltage fed, a high inrush current can be caused, cause device damage, so to use current source；The grid The effect of voltage impulse generator 9 is the voltage of switching control grid, to reach the purpose for opening and closing electron emission, by double Electrode current source obtains big voltage range, changes the voltage of control grid using power supply feedback, when providing positive and negative 250V, can To switch between any two magnitude of voltage of the voltage of control gate lattice in several microseconds between positive and negative 240V；The pulse Compensation amplifier 13 effect be compensated in current measurement it is described extraction grid 6 plus pulse voltage during due to Capacitance Coupled And caused error.

The reason in view of safety and electromagnetic compatibility, all connections are all using shielding between control circuit and electron source High-voltage line, because the screen layer of high-voltage line is ground connection, therefore an obvious electricity can be produced between the extraction grid 6 and ground Hold, and parasitic capacitance existing for script can be increased, as a result, applying pulse to the extraction grid 6 can cause have electricity Stream flows to ground from above-mentioned electric capacity, and cocurrent crosses high-voltage power supply, and the electric current can make rectified current measurement overload, resultant interference emission current control Circuit processed, in order that the influence of this electric current minimizes, add a compensation amplifier and can solve the problem that problem.Due to the electricity of cable Hold the length depending on cable, different parasitic capacitances can be presented in different thermionic emitters devices in addition, it is therefore necessary to Change the gain of compensation amplifier, using two NPN transistors, connect into difference amplifier, the transmitting of the difference amplifier Electric current and gain can be adjusted by the microcontroller.

Claims (1)

1. the control circuit of the small-sized on-radiation electron source with fast-pulse mode of operation, mainly including acceleration voltage source (1), ammeter (2), extract voltage source (3), by filament controller (4-1), current inductor I (4-2), voltage sensor I (4- 3) composition filament heating current source (4), filament (5), extract grid (6), silicon nitride film (7), glass tube with vacuum (8), by electricity Press input port I (9-1), control source port II (9-2), voltage source (9-3), optical fiber I (9-4), voltage amplifier (9-5), Current inductor II (9-6), voltage sensor II (9-7) composition grid voltage impulse generator (9), microprocessor (10), COM modules (11), computer (12), the impulse compensation amplification being made up of offset voltage (13-1), compensation amplifying circuit (13-2) Device (13), the emission current being made up of compensation control circuit (14-1), current amplifier (14-2), integrating circuit (14-3) measure The insulating power supply (16) and optical fiber of module (14) including rectifier I (15-1) high-voltage power supply (15) including rectifier II (16-1) II (17), the compensation amplifying circuit (13-2) include a differential amplifier circuit, and the integrating circuit (14-3) includes One sixteen bit diclinic rate digital analog converter, the bleeding point of glass tube with vacuum (8) are to seal, the filament (5) of tungsten material Positioned at glass tube with vacuum (8) interior one end, thermoelectron is produced after electrified regulation, the extraction grid (6) is located at glass tube with vacuum (8) Before the interior filament (5) and thermal electron stream, glass tube with vacuum can be controlled by changing the field strength of filament surface (8) other end is provided with acceleration electrode made of a copper and its center has the hole of 1 millimeter of a diameter, and the Kong Youyi opens The silicon nitride film (7) sealing of 250 nanometer thickness, electron source inside is vacuum environment, outside is atmospheric environment, and kinetic energy is more than 7keV electronics can pass through the silicon nitride film (7), and the filament (5) and extraction grid (6) are relative to the electricity for accelerating electrode Gesture is all -10kV, and the electric field as caused by electrical potential difference makes the electronics of transmitting accelerate to kinetic energy 10keV, can pass through the silicon nitride Film (7) enters atmospheric environment, has getter in the glass tube with vacuum (8) can keep vacuum environment,

It is characterized in that：In the control circuit, filament controller (4-1), the current inductor of the filament heating current source (4) I (4-2), voltage sensor I (4-3) are all connected with described in microprocessor (10) and the voltage sensor I (4-3) connections respectively Filament (5), microprocessor (10) the difference output reference voltage I, reference voltage II to the grid voltage impulse generator (9) control source port I (9-1) and control source port II (9-2) in, and input voltage amplifier (9-5), the electric current Inductor II (9-6), voltage sensor II (9-7) are all connected with microprocessor (10) and the voltage sensor II (9-7) respectively The compensation amplifying circuit (13-2) of the extraction grid (6) and the impulse compensation amplifier (13), the compensation are connected simultaneously Amplifying circuit (13-2) connects the offset voltage of the emission current measurement module (14) and the impulse compensation amplifier (13) (13-1) connection microprocessor (10), compensation control circuit (14-1), the integrating circuit of the emission current measurement module (14) (14-3) is all connected with microprocessor (10) and the integrating circuit (14-3) connection optical fiber II (17), the emission current respectively Measurement module (14) input is sequentially connected high-voltage power supply (15), insulating power supply (16), and the microprocessor (10) passes through COM modules (11) computer (12) is connected.