CN111982394A - Vacuum degree measuring device, method and system of X-ray tube - Google Patents
Vacuum degree measuring device, method and system of X-ray tube Download PDFInfo
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- CN111982394A CN111982394A CN202010841645.3A CN202010841645A CN111982394A CN 111982394 A CN111982394 A CN 111982394A CN 202010841645 A CN202010841645 A CN 202010841645A CN 111982394 A CN111982394 A CN 111982394A
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Abstract
The present disclosure relates to a vacuum measurement device, method and system for an X-ray tube. The vacuum degree measuring device of the X-ray tube is characterized by comprising: a pulse power supply unit, which is arranged to apply positive pulse voltage to an anode of an X-ray tube to be detected and generate current ionized by collision between free charged particles existing in residual gas in the X-ray tube and residual gas molecules; a measurement circuit unit including a sampling module configured to be connected to the cathode and configured to measure a magnitude of the current; and a processing unit configured to compare the measured magnitude of the current with an a priori ion current-vacuum reference curve to obtain a vacuum degree of the X-ray tube. Therefore, the X-ray tube can be used for measuring the vacuum degree without damage, and has high accuracy and sensitivity.
Description
Technical Field
The invention relates to the technical field of medical instruments, in particular to a vacuum degree measuring technology in an X-ray tube.
Background
An X-ray tube is a vacuum tube that converts a power input into X-rays. The availability of controllable sources of X-rays led to the birth of a new imaging technique for radiology, a technique that images partially opaque objects by penetrating radiation. Unlike other sources of ionizing radiation, X-rays are only generated when the X-ray tube is energized. X-ray tubes are widely used in the fields of Computed Tomography (CT) apparatuses, X-ray diffraction apparatuses, X-ray medical imaging apparatuses, and industrial inspection. The development of high-performance medical X-ray tubes is driven by the ever-increasing demand for high-performance CT scanning devices and angiographic systems.
A vacuum tube used in an X-ray tube includes a cathode filament for emitting electrons to a vacuum, and an anode tube for receiving the emitted electrons, thereby forming a stream of electrons called a beam in the X-ray tube. A high voltage power supply, referred to as the tube voltage, is connected between the anode and cathode filaments to accelerate the electrons. The tube voltage is typically between 30 and 200 kV.
The traditional method for testing the vacuum degree of the X-ray tube needs to destroy the external form of the original X-ray tube, then carries out leak source detection on the tube core after vacuumizing the tube core of the X-ray tube, and needs to vacuumize and seal the X-ray tube again after detecting that no leak source exists, so that the steps are complex. For non-destructive measurements, a common method is to qualitatively measure the vacuum by means of a high frequency electric spark. The electric spark method judges the degree of vacuum by observing the fluorescent color of an electric spark in the tube core of the X-ray tube under high pressure with naked eyes, so that the vacuum level in the X-ray tube can be only roughly estimated, the applicable vacuum range is limited to a low vacuum area, and the method is only applicable to X-ray tube products with transparent glass shells.
Disclosure of Invention
In view of the above, the present disclosure provides, in one aspect, a vacuum degree measuring apparatus of an X-ray tube that can accurately measure a vacuum degree inside the X-ray tube without damage. The vacuum degree measuring device of the X-ray tube comprises: a pulse power supply unit, which is arranged to apply positive pulse voltage to an anode of an X-ray tube to be detected and generate current ionized by collision between free charged particles existing in residual gas in the X-ray tube and residual gas molecules; the measuring circuit unit comprises a sampling module, and the sampling module is arranged to measure the current of the cathode end; and a processing unit configured to compare the measured magnitude of the current with an a priori current-vacuum reference curve to derive a vacuum level of the X-ray tube.
Optionally, the vacuum degree measuring apparatus of the X-ray tube further includes: and the coil unit comprises an excitation coil which is arranged at a position between a cathode and an anode of the X-ray tube and applies a magnetic field to the direction which is intersected with the anode and points to the cathode, so that the free charged particles do spiral motion in a closed area between the cathode and the anode under the action of Lorentz force.
Optionally, the pulse width of the pulse voltage of the vacuum degree measuring device of the X-ray tube ranges from 20 ms to 100ms, and the voltage ranges from 8 kV to 15 kV.
Optionally, the pulse power supply unit of the vacuum measurement device of the X-ray tube further includes a pulse modulator for generating the pulse voltage.
Optionally, the measurement circuit unit of the vacuum degree measurement device of the X-ray tube further comprises an amplifier configured to amplify a signal related to the current; and the sampling module is configured to sample the amplified signal to obtain discrete current values of the current.
Optionally, the measurement circuit unit of the vacuum degree measurement apparatus for an X-ray tube further includes a first power supply, and the sampling module includes a current meter, wherein the first power supply is connected to the sampling module and configured to supply power to the sampling module, and the first power supply is at least set to be electromagnetically isolated from the pulse power supply unit.
Optionally, the value of the magnetic induction intensity of the magnetic field applied by the exciting coil of the vacuum degree measuring device of the X-ray tube ranges from 0.2T to 0.3T.
Optionally, the coil unit of the vacuum degree measuring apparatus of the X-ray tube further includes: and a second power supply configured to be connected to the exciting coil and supply power to the exciting coil.
Optionally, the vacuum degree measuring apparatus of the X-ray tube further includes: and the protection circuit comprises a switch, and the switch is at least respectively connected to the pulse power supply unit and the power supply input end of the second power supply so as to trigger the switching-off or switching-on of the pulse power supply unit and the second power supply.
Another aspect of the present disclosure provides a vacuum degree measuring method of an X-ray tube. The vacuum degree measuring method of the X-ray tube comprises the following steps: applying positive voltage to an anode of an X-ray tube to be detected by utilizing a pulse power supply so as to generate current for ionization caused by collision between free charged particles existing in residual gas in the X-ray tube and residual gas molecules; applying a magnetic field at a location between a cathode and an anode of the X-ray tube in a direction transverse to the direction in which the anode points towards the cathode; comparing the measured magnitude of the current with a priori current-vacuum reference curve to obtain the vacuum of the X-ray tube.
Another aspect of the present disclosure provides a vacuum measurement system for an X-ray tube. This vacuum measurement system includes: the vacuum degree measuring device of the X-ray tube as described above; and an X-ray tube including a cathode, an anode, and a housing portion sealing the cathode and the anode.
Preferably, the X-ray tube vacuum measurement system further comprises a protective cabinet provided for accommodating the X-ray tube and a vacuum measurement device of the X-ray tube, and having a protective cabinet door serving as a safety switch of the system, wherein the safety switch is connected to a protective circuit including a relay connected at least to the pulse power supply unit and a power supply input terminal of a second power supply provided to be connected to and supply power to an exciting coil, respectively, and configured to trigger turning off of the pulse power supply unit and the second power supply when the protective cabinet door is opened, and to trigger turning on of the pulse power supply unit and the second power supply when the protective cabinet door is closed, wherein the exciting coil is provided at a position between a cathode and an anode of the X-ray tube, and applying a magnetic field transverse to the direction of the anode pointing to the cathode.
One advantage of the vacuum measurement device for an X-ray tube provided by the present disclosure is that by applying a pulse voltage with a certain high voltage and pulse width to an anode of an X-ray tube to be measured, collisions between free charged particles in residual gas in the X-ray tube and residual rarefied gas molecules are ionized, and an ion current that can be observed is generated, so that the vacuum in the X-ray tube can be measured at low cost and nondestructively.
Another advantage of the present disclosure is that a transverse magnetic field is applied between the anode and the cathode of the X-ray tube by the coil unit, so that the residual free charged particles make a spiral motion between the two electrodes under the action of the lorentz force, thereby lengthening the stroke of the free charged particles, increasing the probability of collision between the free charged particles and the residual gas molecules, and increasing the measurability of the ion current, so as to sensitively detect the small change of the ion current, improve the measurement sensitivity, and simultaneously reduce the technical requirements for high voltage and pulse width provided by the pulse power supply unit, and reduce the design difficulty. Can measure 10-4Pa～10-1Pa, i.e. 10-6mbar～10-3Vacuum in the mbar range.
Another advantage of the present disclosure is that the vacuum measurement device, method and system can be applied to quality monitoring of daily production, finding the condition of bad products in the early period, avoiding a large amount of rework man-hours and rework scrapped materials caused by bad products flowing to the back end, improving production efficiency and saving cost.
Drawings
The above and other features and advantages of the present invention will become more apparent to those of ordinary skill in the art by describing in detail embodiments thereof with reference to the attached drawings in which:
FIG. 1 is a block diagram illustrating a vacuum measurement device of an X-ray tube according to one exemplary embodiment;
FIG. 2 is a block diagram illustrating a vacuum measurement device of an X-ray tube according to another exemplary embodiment;
FIG. 3 is a flow chart illustrating a method of vacuum measurement of an X-ray tube according to an exemplary embodiment;
FIG. 4 is a block diagram illustrating a vacuum measurement system of an X-ray tube according to an exemplary embodiment;
FIG. 5 is a circuit diagram illustrating a vacuum measurement device of an X-ray tube according to one exemplary embodiment;
fig. 6 is a schematic diagram illustrating a current-vacuum reference curve for measuring the vacuum of an X-ray tube according to an exemplary embodiment.
Wherein the reference numbers are as follows:
vacuum degree measuring device for 100X-ray tube
101 pulse power supply unit
102 measurement circuit unit
1021 sampling module
1022 first power supply
1023 galvanometer
1024 amplifier
103 coil unit
1031 exciting coil
1032 second power supply
104 processing unit
1041 display device
105 protective circuit
1051 switch
Vacuum degree measuring system of 300X-ray tube
301X-ray tube
303 cathode
305 Anode
307 housing part
Detailed Description
In order to more clearly understand the technical features, objects, and effects of the present invention, embodiments of the present invention will now be described with reference to the accompanying drawings, in which like reference numerals refer to like parts throughout.
"exemplary" means "serving as an example, instance, or illustration" herein, and any illustration, embodiment, or steps described as "exemplary" herein should not be construed as a preferred or advantageous alternative.
For the sake of simplicity, the drawings only schematically show the parts relevant to the present invention, and they do not represent the actual structure as a product. In addition, in order to make the drawings concise and understandable, components having the same structure or function in some of the drawings are only schematically illustrated or only labeled.
In this document, "one" means not only "only one" but also a case of "more than one". In this document, "first", "second", and the like are used only for distinguishing one from another, and do not indicate the degree of importance and order thereof, and the premise that each other exists, and the like.
The operating performance of an X-ray tube is closely related to the parameters of the vacuum environment of its vacuum tube. During manufacture and use of X-ray tubes, vacuum failure of the X-ray tube is a common failure condition. Because the product performance can be greatly influenced by insufficient vacuum degree, the phenomena of ignition, oxidation of internal components, reduction of service life and even failure to cause scrapping can be caused. Particularly, after the X-ray tube is sealed, the reworking or scrapping of the X-ray tube under many conditions can be avoided through a technology of nondestructively and accurately measuring the internal vacuum degree of the X-ray tube.
The invention provides a vacuum degree measuring device of an X-ray tube, which lengthens the stroke of electrons between vacuum tubes by applying a magnetic field between a cathode and an anode of the X-ray tube, and measures the ion current generated after partial free charged ions existing in residual gas in the vacuum tubes of the X-ray tube collide with rarefied gas molecules remained in the vacuum tubes to be ionized through a measuring circuit, so that the size of the formed measurable ion current can be measured, and the vacuum degree measuring device can be compared with a current-vacuum degree reference curve to obtain the vacuum degree of the X-ray tube. The method for measuring the vacuum degree of the X-ray tube can be used for measuring the vacuum degree of the X-ray tube rapidly and accurately without damage.
Fig. 1 is a block diagram illustrating a vacuum degree measuring apparatus of an X-ray tube according to an exemplary embodiment.
As shown in fig. 1, the vacuum measuring apparatus 100 for an X-ray tube includes: the measurement circuit unit 102 comprises a sampling module 1021, the sampling module 1021 is used for measuring the current of the cathode end, and the processing unit 104 is configured to compare the measured current with a priori current-vacuum reference curve so as to obtain the vacuum degree of the X-ray tube.
A pulse voltage is applied to the anode end of the X-ray tube to be measured, so that a strong electric field (electrostatic field) can be applied between the cathode and the anode of the X-ray tube. The strong electric field can be directed to the cathode from the anode of the X-ray tube, and under the action of the strong electric field, free charged particles existing in residual gas in the X-ray tube collide with residual rarefied gas molecules in the process of moving in the electric field to generate ionization, so that electrons and ions are generated, and current is formed. The lower the vacuum degree in the X-ray tube is, the more rarefied gas molecules in the X-ray tube are, the more electrons and ions are generated by bombardment of charged particles and gas molecules, and the larger the current is.
It should be noted that the method for obtaining the current-vacuum reference curve may use a plurality of X-ray tubes with different vacuum values as the X-ray tube to be measured, and the vacuum values of the X-ray tubes are determined. The current magnitude of the X-ray tube may be measured by applying a positive pulse voltage to the X-ray tube using a vacuum measurement device of the X-ray tube, thereby obtaining a priori current-vacuum reference curve as a reference curve. In addition, the values of the current generated by the collision between the charged particles and the residual gas molecules measured for a plurality of X-ray tubes with different vacuum values are discrete, and a continuous current-vacuum reference curve can be obtained by using a fitting algorithm, an interpolation algorithm, or the like, in order to obtain a continuous current-vacuum reference curve. When the current-vacuum degree reference curve is used, the corresponding vacuum degree value can be found only according to the measured current value, so that the vacuum degree of the X-ray tube is confirmed. In this regard, the present embodiment does not limit this.
The sampling module 1021 may measure the magnitude of the current, particularly the discrete value of the current, by sampling the current signal.
The processing unit 104 may include a memory that may store a current-vacuum reference curve. In addition, the processing unit may further include a display device 1041, and the display device 1041 may display the vacuum degree value corresponding to the current value measured by the relevant X-ray tube. Further, the display device 1041 may also be configured to display the measured current value for the X-ray tube. Here, the processing unit 104 may be a single chip or a central processing unit (MCU), and the like, which is not limited in this embodiment.
Fig. 2 is a block diagram illustrating a vacuum degree measuring apparatus of an X-ray tube according to another exemplary embodiment.
According to some embodiments, as shown in fig. 2, in order to increase the probability of collision between the residual free charged particles and the residual gas molecules in the X-ray tube, the stroke of the free charged particles in the X-ray tube may be increased, and the vacuum measurement apparatus of the X-ray tube further includes: the coil unit 103, which includes an excitation coil, is disposed at a position between the cathode and the anode of the X-ray tube, and applies a magnetic field in a direction transverse to the direction of the anode toward the cathode, so that electrons and ions generated by ionization of the freely charged particles and gas molecules make a spiral motion in the vacuum tube region of the cathode and the anode under the action of the magnetic field. Wherein the direction of the generated current movement is from the anode to the cathode.
According to some embodiments, the coil unit may comprise an excitation coil 1031, the magnetic field applied by the excitation coil 1031 in a direction transverse to the direction in which the anode is directed towards the cathode causing free charged particles to spiral under the influence of lorentz forces in the vacuum region of the X-ray tube. In addition, the magnetic field applied by the excitation coil 1031 may also be understood as being simultaneously transverse to the direction of motion of the free charged particles under the influence of the electrostatic field. Therefore, under the action of the magnetic field applied by the excitation coil 1031, the probability of collision between the charged particles and the gas molecules is increased, so that the charged particles and the gas molecules in the X-ray tube are sufficiently collided, and thus the actual current can be obtained, and the degree of vacuum in the X-ray tube can be more accurately reflected. In some embodiments, there may be a plurality of excitation coils 1031 that may be arranged in opposition between the cathode and anode of the X-ray tube to provide for application of a magnetic field transverse to the direction of current movement. One advantage of the above concept is that the requirements of pulse voltage and pulse width applied by the pulse power supply unit 101 are reduced, the current signal is clearer, the interference resistance is better, and the measurement of the actual current is easier and more accurate.
According to some embodiments, in order to enable the pulse power supply unit 101 to apply a suitable strong electric field between the anode and the cathode of the X-ray tube, the pulse width of the pulse voltage may be set to a range of 20 to 100ms and the voltage may be 8 to 15 kV.
According to some embodiments, the pulse power supply unit 101 further comprises a pulse modulator for modulating the generated pulse voltage. The pulse modulator can modulate the pulse voltage to have the pulse width with the value range of 20-100 ms and the voltage of 8-15 kV.
According to some embodiments, the ionization is generated due to collisions between free charged particles in the residual gas in the X-ray tube and residual rarefied gas molecules, the current-related signal generated by the ionization is weak, for which purpose the measurement circuit unit 102 further comprises an amplifier 1024, the amplifier 1024 being arranged to amplify the current-related signal, and the sampling module 1021 being arranged to acquire the amplified signal for obtaining discrete current values with respect to the current.
According to some embodiments, in order to enable the measurement circuit unit 102 to obtain a value for measuring the current and avoid interference of a pulse voltage and a high voltage signal when sampling the current to measure its current value, an independent power supply may be provided for the measurement circuit unit 102 to improve accuracy and robustness of measuring the current, for this reason, the measurement circuit unit 102 further includes a first power supply 1022, and a sampling module 1021, and the first power supply 1022 is connected to the sampling module 1021 and configured to supply power to the sampling module 1021. Wherein the first power source 1022 may be at least arranged to be electromagnetically isolated from the pulsed power supply unit 101, and wherein the sampling module 1021 comprises a current meter 1023 for measuring the current at the cathode terminal. Accordingly, the first power source 1022 may be disposed in an electromagnetically shielded housing to prevent signal interference of the high voltage part of the pulse power source unit 101.
According to some embodiments, in order to enable the excitation coil 1031 to generate a magnetic field with appropriate magnetic induction intensity, so that the moving trajectory of the free charged particles in the residual gas in the X-ray tube forms a spiral trajectory during the movement of the free charged particles in the X-ray tube, the collision between the free charged particles and gas molecules is increased to generate sufficient ionization, so as to truly reflect the vacuum degree of the X-ray tube, for this reason, the magnetic induction intensity of the magnetic field applied by the excitation coil 1031 ranges from 0.2T to 0.3T.
According to some embodiments, in order for the excitation coil 1031 to generate a magnetic field of appropriate magnetic induction, a certain voltage is supplied to the excitation coil 1031, i.e., may be determined according to the magnetic induction of the magnetic field, the number of turns of the excitation coil 1031, and the like. For this purpose, the coil unit 103 further includes: and a second power supply 1032 that is connected to the excitation coil 1031 and supplies power to the excitation coil 1031. The second power supply 1032 may provide a more suitable and stable voltage value, which may range from approximately 100V to 1000V. Therefore, the second power supply 1032 is required to independently supply power to the excitation coil 1031.
According to some embodiments, since the pulse power supply unit 101 and the second power supply 1032 operate at higher voltage values, there is a certain risk that the vacuum degree measuring apparatus of the X-ray tube further optionally includes: the protection circuit 105, the protection circuit 105 may include at least one switch 1051, and the switch 1051 is configured to be connected to at least the power input terminals of the pulse power supply unit 101 and the second power supply 1032, respectively, so as to trigger turning off or turning on of the pulse power supply unit 101 and the second power supply 1032. Certain trigger conditions and conditions may be set to trigger the turning off of the pulse power supply unit 101 and the second power supply 1032, for example, during the measurement of the vacuum degree of the X-ray tube to be measured, the situation that a positive pulse voltage is applied to the anode of the X-ray tube to be measured by the pulse power supply unit 101 in an open environment, and/or a certain high voltage is applied to the exciting coil 1031 by the second power supply 1032 is judged. Here, the on/off triggering of the switch 1051 may be implemented by a relay.
According to another aspect of the present disclosure, there is also provided a vacuum degree measuring method of an X-ray tube.
Fig. 3 shows a flow chart of a method of vacuum measurement of an X-ray tube according to an exemplary embodiment.
As shown in fig. 3, a vacuum degree measuring method of an X-ray tube according to an embodiment of the present disclosure includes:
s201: a positive pulse voltage is applied to an anode of an X-ray tube to be tested by utilizing a pulse power supply so as to generate current for ionization caused by collision between free charged particles existing in residual gas in the X-ray tube and residual rarefied gas molecules.
S202: a magnetic field is applied at a location between a cathode and an anode of the X-ray tube in a direction transverse to the direction in which the anode points towards the cathode.
S203: the magnitude of the measured current is compared to an a priori current-vacuum reference curve to obtain the vacuum of the X-ray tube.
It should be noted that, the method for obtaining the current-vacuum degree reference curve may use a plurality of X-ray tubes with different vacuum degrees as the X-ray tube to be measured, and the vacuum degree value of the X-ray tube is determined. The magnitude of the current can be measured by the above steps S201 to S203 for a plurality of X-ray tubes with different known vacuum values, respectively, and the current is generated by applying a positive pulse voltage to the anode end of the X-ray tube to form a strong electric field so that the residual free charged particles in the X-ray tube move under the action of the electric field and collide with the residual gas molecules to ionize. By measuring this current value and the known corresponding vacuum value, an a priori current-vacuum reference curve is obtained/plotted as a reference curve. A continuous current-vacuum reference curve can be obtained based on the discrete current-vacuum values using a fitting algorithm, an interpolation algorithm, and the like. The above-mentioned method is not described herein in detail.
According to another aspect of the present disclosure, there is also provided a vacuum measurement system of an X-ray tube.
FIG. 4 illustrates a vacuum measurement system of an X-ray tube according to one exemplary embodiment.
As shown in fig. 4, the vacuum degree measurement system 300 of the X-ray tube 301 includes: a vacuum degree measuring apparatus 100 of an X-ray tube 301, and the X-ray tube 301 include a cathode (filament) 303, an anode 305, and a casing portion 307 enclosing the cathode and the anode. The cathode 303 may include a cathode filament, among other things.
Wherein, the positive terminal of the pulse power supply unit in the vacuum degree measuring device 100 of the X-ray tube 301 is connected with the anode 305 of the X-ray tube 301, the negative terminal of the pulse power supply unit is connected with the cathode (filament) 303 of the X-ray tube 301, after the pulse power supply unit provides positive pulse voltage to the anode 305 of the X-ray tube 301, a strong electric field is applied between the cathode 303 and the anode 305 of the X-ray tube 301, so that free charged particles existing in residual gas in the X-ray tube 301 collide with residual gas molecules to generate ionization, electrons and ions are generated, and the current generated due to the collision moves to the cathode, so that the current can be measured by the cathode terminal, and the vacuum degree of the X-ray tube 301 is obtained by comparing/searching a current-vacuum degree reference curve.
Therefore, in the above manner, a strong electric field is applied between the cathode and the anode in the X-ray tube by applying a positive pulse voltage to the anode without destroying the X-ray tube 301, so that the free charged particles in the residual gas collide with the gas molecules to be ionized, and therefore, the vacuum degree of the X-ray tube 301 can be obtained only by measuring the current value generated by the ionization at the anode of the X-ray tube 301, which is highly economical.
According to some illustrated embodiments, to protect the safety of the user during the measurement of the vacuum level of the X-ray tube 301, a safety switch needs to be provided for the pulse power supply unit and the second power supply 1032 for this purpose. For this, the vacuum measuring system 300 of the X-ray tube further includes: and a protection cabinet which is arranged to accommodate the X-ray tube 301 and the vacuum degree measuring device 100 of the X-ray tube and has a protection cabinet door used as a safety switch of the system, wherein the protection cabinet door is connected to a protection circuit, the protection circuit comprises a switch 1051, the switch 1051 at least acts on the power input ends of the pulse power supply unit 101 and the second power supply 1032 respectively, and the switch 1051 is configured to trigger the turn-off of the pulse power supply unit 101 and the second power supply 1032 when the protection cabinet door is opened and trigger the turn-on of the pulse power supply unit 101 and the second power supply 1032 when the protection cabinet door is closed. The protection cabinet door is opened corresponding to the X-ray tube 301 and the vacuum degree measuring device 100 of the X-ray tube in the protection cabinet and communicated with the external environment, and the protection cabinet door is closed corresponding to the protection cabinet and the external environment. In addition, in order to ensure that the protection cabinet door ensures the locking of the protection cabinet during the measurement of the vacuum degree of the X-ray tube 301, the protection cabinet may further include an electromagnetic lock (not shown), the electromagnetic lock acts on the protection cabinet door, and the electromagnetic lock may be configured to be triggered to lock the protection cabinet door when the switch 1051 triggers the opening of the pulse power supply unit 101 and the second power supply 1032 and the X-ray tube vacuum degree measurement apparatus 100 starts to measure the vacuum degree of the X-ray tube 301 after the alternating current is supplied to the pulse power supply unit 101 and the second power supply 1032. Here, the off/on triggering of the switch 1051 may be implemented by a relay.
In addition, the power input terminals of the pulse power supply unit 101 and the second power supply 1032 can represent receiving 220V ac power. Here, the 220V ac power can be fed to the pulse power supply unit 101 and the second power supply 1032 through a pair of the zero line N and the live line L, which is not described in detail in this embodiment.
Fig. 5 shows a circuit diagram of a vacuum measurement device of an X-ray tube according to an exemplary embodiment.
As shown in fig. 5, the pulse power supply unit 101 and the X-ray tube 301 to be measured in vacuum degree form a loop, specifically, the positive pole of the pulse power supply unit 101 is connected to the anode 305 of the X-ray tube 301, the negative pole of the pulse power supply unit 101 is connected to the cathode 303 of the X-ray tube 301, by applying a positive pulse voltage to the anode 305, the free charged particles of the residual gas in the X-ray tube 301 are excited under the action of the strong electric field to move in the X-ray tube 301 under the action of the electric field, and collide with the residual gas molecules to generate ionization during the movement, and the ionization particles form an observable current to determine the vacuum degree in the X-ray tube.
Further, a second power supply 1032 constitutes another circuit together with the X-ray tube 301 whose degree of vacuum is to be measured and the exciting coil 1031, and the second power supply 1032 can be connected to the exciting coil 1031 through a cable wire and feeds a certain high voltage to the exciting coil 1031. In particular, the excitation coil 1031 may be arranged at a position between the anode and the cathode of the X-ray tube and applies a magnetic field transverse to the direction of movement of the free charged particles such that the free charged particles make a helical movement in the region of the anode and the cathode under the influence of the magnetic field. Here, a plurality of excitation coils 1031 may be oppositely arranged along the cathode and the anode of the X-ray tube 301. For this, the second power source 1032 may feed a high voltage to the corresponding excitation coil 1031 through a plurality of cable wires, and the high voltage provided by the second power source 1032 may make the excitation coil 1031 generate a magnetic field of 0.2T to 0.3T, so that the free charged particles and the residual gas molecules sufficiently collide to generate ionization-related current, thereby obtaining an accurate measurement of the vacuum degree.
Furthermore, the measurement circuit unit 102 may be connected to the cathode 303 of the X-ray tube 301 under test to measure the observable current magnitude generated by ionization of free charged particles due to collision with gas molecules through the sampling module 1021, and in particular, to collect the current value of the current dispersion through the sampling module 1021. Here, the sampling module 1021 includes a current meter 1023, and the current meter 1023 can be connected in series with the cathode of the X-ray tube 301 to be measured to measure the current value of the current.
In addition, the protection circuit 105 may form a protection loop with a protection cabinet of the vacuum measuring device 100 accommodating the X-ray tube 301 and the X-ray tube. According to an embodiment, the protection circuit 105 may be connected to a protection cabinet door, and the protection cabinet door may be used as a safety switch, so that the opening and closing of the protection cabinet door is used as a trigger for the protection circuit 105 to act on the pulse power supply unit 101 and the second power supply 1032 to turn on and off to protect the measurement safety of the user. Specifically, the protection circuit 105 may include at least one switch 1051, where the switch 1051 is configured to be connected to at least the power input terminals of the pulse power supply unit 101 and the second power supply 1032, respectively, so as to trigger the turn-off or turn-on of the pulse power supply unit 101 and the second power supply 1032, and is configured to trigger the turn-off of the pulse power supply unit 101 and the second power supply 1032 when the protection cabinet door is opened. In addition, in order to ensure that the protection cabinet door ensures the locking of the protection cabinet during the measurement of the vacuum degree of the X-ray tube 301, the protection cabinet may further include an electromagnetic lock (not shown), the electromagnetic lock acts on the protection cabinet door, and the electromagnetic lock may be configured to be triggered to lock the protection cabinet door when the switch 1051 triggers the opening of the pulse power supply unit 101 and the second power supply 1032 and the X-ray tube vacuum degree measurement apparatus 100 starts to measure the vacuum degree of the X-ray tube 301 after the pulse power supply unit 101 and the second power supply 1032 are supplied with alternating current, so as to ensure the locking of the protection cabinet. Here, the off/on triggering of the switch 1051 may be implemented by a relay.
Fig. 6 is a schematic diagram illustrating a current-vacuum reference curve for measuring the vacuum of an X-ray tube according to an exemplary embodiment.
As shown in fig. 6, the current-vacuum reference curve may be obtained based on the measurement of the vacuum degree measuring apparatus 100 of the X-ray tube for a plurality of X-ray tubes with different vacuum degrees, and specifically, the setting of the measurement environment of the vacuum degree measuring apparatus 100 of the X-ray tube may be as follows: the pulse power supply unit 101 can provide a pulse voltage with a voltage of 8-15 kV and a pulse width of 20-100 ms, and the second power supply 1032 can provide a certain suitable voltage, which is about 100-1000V, so that the exciting coil 1031 can generate a magnetic field of 0.2T-0.3T.
As seen from the current-vacuum reference curve shown in FIG. 6, the current-vacuum reference curve is at 10 under the above measurement conditions-7mbar～10- 3The vacuum degree in the mbar range has an accurate one-to-one correspondence relationship with the current value, wherein the range of the accurately corresponding current value is between 10 muA and 10000 muA.
In the above embodiments of the present application, the descriptions of the respective embodiments have respective emphasis, and for parts that are not described in detail in a certain embodiment, reference may be made to related descriptions of other embodiments.
In the embodiments provided in the present application, it should be understood that the disclosed technology can be implemented in other ways. The above-described embodiments of the apparatus are merely illustrative, and for example, the division of the units or modules is only one logical division, and there may be other divisions when the actual implementation is performed, for example, a plurality of units or modules or components may be combined or integrated into another system, or some features may be omitted or not executed.
In addition, functional units or modules in the embodiments of the present application may be integrated into one processing unit or module, or each unit or module may exist alone physically, or two or more units or modules are integrated into one unit or module. The integrated unit or module may be implemented in the form of hardware, or may be implemented in the form of a software functional unit or module.
The foregoing is only a preferred embodiment of the present application and it should be noted that those skilled in the art can make several improvements and modifications without departing from the principle of the present application, and these improvements and modifications should also be considered as the protection scope of the present application.
Claims (12)
1. A vacuum measuring apparatus of an X-ray tube, comprising:
a pulse power supply unit (101) configured to apply a positive pulse voltage to an anode of an X-ray tube to be tested, and generate an electric current ionized by collision between free charged particles present in residual gas in the X-ray tube and residual gas molecules;
a measurement circuit unit (102) comprising a sampling module (1021), the sampling module (1021) being arranged to measure the magnitude of the current at the cathode terminal; and
a processing unit (104) configured to compare the measured magnitude of the current with an a priori current-vacuum reference curve to derive a vacuum level of the X-ray tube.
2. The vacuum degree measuring apparatus of the X-ray tube according to claim 1, further comprising:
coil unit (103) comprising an excitation coil (1031), said excitation coil (1031) being arranged at a position between a cathode and an anode of said X-ray tube and applying a magnetic field in a direction transverse to the direction of said anode directed towards said cathode such that said free charged particles are caused to spiral under the influence of lorentz forces in a closed area between said cathode and said anode.
3. The vacuum degree measuring device of the X-ray tube according to claim 1, wherein the pulse width of the pulse voltage ranges from 20 ms to 100ms, and the voltage ranges from 8 kV to 15 kV.
4. The vacuum measurement device of an X-ray tube according to claim 1, wherein the pulsed power supply unit (101) further comprises a pulse modulator for generating the pulsed voltage.
5. The vacuum measurement device of an X-ray tube according to claim 1, wherein the measurement circuit unit (102) further comprises an amplifier arranged to amplify the signal related to the current; and
the sampling module (1021) is configured to sample the amplified signal to obtain a current value of the current.
6. The vacuum measurement device of an X-ray tube according to claim 1, wherein the measurement circuit unit (102) further comprises a first power supply (1022) and the sampling module (1021) comprises a current meter (1023), wherein,
the first power supply (1022) is connected to the sampling module (1021) and configured to power the sampling module (1021), and the first power supply (1022) is at least arranged to be electromagnetically isolated from the pulsed power supply unit (101).
7. The X-ray tube vacuum measurement apparatus according to claim 2, wherein the magnetic induction of the magnetic field applied by the excitation coil (1031) ranges from 0.2T to 0.3T.
8. The vacuum measurement device of the X-ray tube according to claim 2, wherein the coil unit (103) further comprises:
a second power supply (1032) arranged in connection with the excitation coil (1031) and supplying power to the excitation coil (1031).
9. The vacuum measuring apparatus of the X-ray tube according to claim 8, further comprising:
a protection circuit (105) comprising a switch connected at least to the power supply inputs of the pulsed power supply unit (101) and the second power supply (1032), respectively, to trigger the switching off or on of the pulsed power supply unit (101) and the second power supply (1032).
10. A method of measuring a degree of vacuum of an X-ray tube, comprising:
applying positive voltage to an anode of an X-ray tube to be detected by utilizing a pulse power supply so as to generate current for ionization caused by collision between free charged particles existing in residual gas in the X-ray tube and residual gas molecules;
applying a magnetic field at a location between a cathode and an anode of the X-ray tube transverse to a direction pointing toward the cathode transverse to the anode;
comparing the measured magnitude of the current with a priori current-vacuum reference curve to obtain the vacuum of the X-ray tube.
11. A vacuum measurement system for an X-ray tube, comprising:
a vacuum degree measuring device of the X-ray tube according to any one of claims 1 to 9; and
an X-ray tube (301) comprising a cathode (303), an anode (305), and a housing portion (307) sealing the cathode (303) and the anode (305).
12. The vacuum measurement system of the X-ray tube according to claim 11, further comprising: a protective cabinet arranged for accommodating the X-ray tube (301) and a vacuum measuring device (100) of the X-ray tube and having a protective cabinet door serving as a safety switch of the system, wherein,
the protection cabinet door is connected to a protection circuit (105) comprising a switch connected at least to the pulsed power supply unit and to a power input of a second power supply arranged to be connected to and to supply power to an excitation coil, respectively, and configured to trigger the switching off of the pulsed power supply unit and the second power supply when the protection cabinet door is open, and to trigger the switching on of the pulsed power supply unit and the second power supply when the protection cabinet door is closed, wherein the excitation coil is arranged in a position between a cathode and an anode of the X-ray tube and applies a magnetic field in a direction transverse to the direction of the anode directed to the cathode.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010841645.3A CN111982394A (en) | 2020-08-20 | 2020-08-20 | Vacuum degree measuring device, method and system of X-ray tube |
| DE102021121570.6A DE102021121570A1 (en) | 2020-08-20 | 2021-08-19 | Apparatus, method and system for measuring the degree of vacuum of an X-ray tube |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010841645.3A CN111982394A (en) | 2020-08-20 | 2020-08-20 | Vacuum degree measuring device, method and system of X-ray tube |
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| CN111982394A true CN111982394A (en) | 2020-11-24 |
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| CN202010841645.3A Withdrawn CN111982394A (en) | 2020-08-20 | 2020-08-20 | Vacuum degree measuring device, method and system of X-ray tube |
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| DE (1) | DE102021121570A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113959632A (en) * | 2021-11-29 | 2022-01-21 | 华北电力大学 | Vacuum degree detection method for vacuum electrical equipment based on low-energy X-ray ionization |
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| DE102021121570A1 (en) | 2022-02-24 |
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Application publication date: 20201124 |