Device, method and system for measuring the vacuum level of an X-ray tube

Abstract

Device for measuring the vacuum level of an X-ray tube, characterized in that it comprises: a pulse voltage supply unit (101) configured to apply a positive pulse voltage to an anode of an X-ray tube to be measured in order to generate a current resulting from ionization as a result of a collision between free charged particles present in a residual gas inside the X-ray tube and remaining gas molecules, a measuring circuit unit (102) comprising a scanning module (1021), wherein the scanning module (1021) is configured to measure the magnitude of the current at the cathode, and to compare the magnitude of the current with a priori current-vacuum degree reference curve and thus determine the vacuum degree of the X-ray tube.

Description

TECHNICAL FIELD

[0001] The present invention relates to the technical field of medical devices, in particular to a technique for measuring the degree of vacuum within an X-ray tube. STATE OF THE ART

[0002] An X-ray tube is a vacuum tube that converts the input of a power supply into X-rays. Controllable sources of usable X-rays contribute to the creation of a new radioactive imaging technique, in which an image of a partially opaque object is created using transmitted radiation. Unlike other sources of ionizing radiation, X-rays are only generated after an X-ray tube is energized. X-ray tubes are widely used in computed tomography (CT) systems, X-ray diffraction systems, medical X-ray imaging systems, and industrial defect detection. The ever-increasing demand for high-performance CT scanning systems and angiography systems is driving the development of high-performance X-ray tubes for medical applications.

[0003] The vacuum tube used in an X-ray tube consists of a cathode wire for emitting electrons into the vacuum and an anode tube for receiving the emitted electrons, creating a stream of electrons called a beam within the X-ray tube. A high-voltage power supply, called the tube voltage, is connected between the anode and cathode wire to accelerate the electrons. The tube voltage is typically between 30 and 200 kV.

[0004] Conventional methods for measuring the vacuum level of an X-ray tube require destroying the outer structure of the X-ray tube, evacuating the core of the X-ray tube, and then detecting a leak at the core. If no leak is detected, the X-ray tube must be evacuated and sealed again. This requires more complicated steps. For non-destructive measurement, conventional methods qualitatively measure the vacuum level using high-frequency electrical sparks. The electric spark method determines the vacuum level by observing the fluorescent color of the electric sparks inside the core of the X-ray tube at a high voltage with the naked eye, which is why the vacuum level inside the X-ray tube can only be roughly estimated. Furthermore, its applicability is limited to low-vacuum applications and X-ray tube products with transparent glass enclosures.

[0005] According to JP 2016 - 146 288 A, an X-ray tube device comprises a negative electrode formed by a bundle for bundling an electron-emitting electron source and the electrons emitted from the electron source, a positive electrode arranged at a prescribed distance from the negative electrode and emitting X-rays by being impinged upon by the electrons emitted from the electron source, a vacuum envelope internally enclosing the negative electrode and the positive electrode and maintaining an inner part in a vacuum state, an ammeter measuring a current value flowing between the negative electrode and the positive electrode or the negative electrode and the vacuum envelope, a first power supply applying a voltage to the electron source, and a second power supply applying the voltage to the electron source and the bundle.

[0006] KR 10 2016 0 118 613 A relates to a method and apparatus for measuring the vacuum level of a manufactured X-ray source. The apparatus comprises a power source connected to a cathode and an anode of the X-ray source, and an ion measuring device connected to the anode. The method comprises a step of indicating a relationship between ion concentration and vacuum level, and a step of measuring the ion concentration of the X-ray source and calculating the vacuum level of the X-ray source using a relationship between ion concentration and vacuum level.

[0007] DE 11 2018 005 680 T5 discloses an X-ray tube with a shell that maintains a predetermined pressure in its interior and contains an electron-emitting cathode and an anode facing the cathode, the anode generating X-rays. The shell comprises a shell body and an X-ray window portion that has a higher transmittance for X-rays and a higher electrical conductivity than the shell body. If one part of the X-ray window portion or the anode is set to a lower electrical potential than another part of the X-ray window portion or the anode, detection of an ion current or an electron current through the other part is possible. DISCLOSURE OF THE INVENTION

[0008] In this regard, according to one aspect of the present disclosure, an apparatus for measuring the degree of vacuum of an X-ray tube is provided, with which the degree of vacuum within an X-ray tube can be measured accurately and non-destructively.The device for measuring the degree of vacuum of an X-ray tube comprises: a pulse voltage supply unit configured to apply a positive pulse voltage to an anode of an X-ray tube to be measured in order to generate a current resulting from ionization due to a collision between free charged particles present in a residual gas within the X-ray tube and remaining gas molecules; a measuring circuit unit comprising a sampling module configured to measure the magnitude of the current at the cathode; and a processing unit configured to compare the measured magnitude of the current with an a priori current-degree of vacuum reference curve and thus determine the degree of vacuum of the X-ray tube.

[0009] The device for measuring the degree of vacuum of an X-ray tube optionally further comprises: a coil unit comprising an excitation coil arranged between the cathode and the anode of the X-ray tube and applying a magnetic field in a direction transverse to the anode and pointing towards the cathode, so that the free charged particles perform a spiral movement within a closed region between the cathode and the anode under the action of a Lorentz force.

[0010] Optionally, the device for measuring the degree of vacuum of an X-ray tube is provided with a pulse width of the pulse voltage between 20 and 100 ms and a voltage between 8 and 15 kV.

[0011] Optionally, in the device for measuring the degree of vacuum of an X-ray tube, the pulse voltage supply unit further comprises a pulse modulator for generating the pulse voltage.

[0012] Optionally, in the device for measuring the degree of vacuum of an X-ray tube, the measuring circuit unit further comprises an amplifier configured to amplify a signal associated with the current, wherein the sampling module is configured to sample the amplified signal to obtain a discrete current value of the current.

[0013] Optionally, in the device for measuring the degree of vacuum of an X-ray tube, the measuring circuit unit further comprises a first power supply and the scanning module comprises an ammeter, wherein the first power supply is connected to the scanning module and is configured to supply power to the scanning module, wherein the first power supply is configured to be electromagnetically isolated at least from the pulse voltage supply unit.

[0014] Optionally, in the device for measuring the degree of vacuum of an X-ray tube, the magnetic field applied by the excitation coil has a magnetic flux density of 0.2 T to 0.3 T.

[0015] The coil unit of the device for measuring the degree of vacuum of an X-ray tube optionally further comprises a second power supply connected to the excitation coil and supplying power to the excitation coil.

[0016] The device for measuring the degree of vacuum of an X-ray tube optionally further comprises a protection circuit comprising a switch connected at least to the pulse voltage supply unit and a current input of the second power supply in order to trigger the switching on and off of the pulse voltage supply unit and the second power supply.

[0017] According to another aspect of the present disclosure, a method for measuring the vacuum degree of an X-ray tube is provided. The method for measuring the vacuum degree of an X-ray tube comprises: applying a positive voltage to an anode of an X-ray tube to be measured using a pulse voltage supply to generate a current resulting from ionization due to a collision between free charged particles present in a residual gas within the X-ray tube and remaining gas molecules; and applying a magnetic field between the cathode and the anode of the X-ray tube in a direction transverse to the anode and pointing toward the cathode, and comparing the measured magnitude of the current with an a priori current-vacuum degree reference curve to determine the vacuum degree of the X-ray tube.

[0018] According to another aspect of the present disclosure, a system for measuring the vacuum level of an X-ray tube is provided. The vacuum level measuring system comprises: the above-described device for measuring the vacuum level of an X-ray tube and an X-ray tube including a cathode, an anode, and a housing portion sealing the cathode and the anode.

[0019] Preferably, the system for measuring the degree of vacuum further comprises a protective cabinet configured to accommodate the X-ray tube and the device for measuring the degree of vacuum of an X-ray tube, wherein the protective cabinet has a protective cabinet door serving as a safety switch of the system, wherein the safety switch is connected to a protective circuit comprising a relay connected at least to the pulse voltage supply unit and a current input of a second power supply connected to an excitation coil and supplying current to the excitation coil, wherein the relay is configured to trigger the switching off of the pulse voltage supply unit and the second power supply upon opening of the protective cabinet door and to trigger the switching on of the pulse voltage supply unit and the second power supply upon closing of the protective cabinet door.wherein the excitation coil is arranged between the cathode and the anode of the X-ray tube and applies a magnetic field in a direction transverse to the anode and pointing towards the cathode.

[0020] An advantage of the device for measuring the degree of vacuum of an X-ray tube according to the present disclosure is that by applying a pulse voltage with a specific high voltage and a specific pulse width to the anode of an X-ray tube to be measured, ionization occurs as a result of a collision between free charged particles in a residual gas within the X-ray tube and molecules of the remaining thin gas, thereby generating an observable ion current. Thus, a cost-effective and non-destructive measurement of the degree of vacuum within the X-ray tube is achieved.

[0021] Another advantage of the present disclosure is that, by applying a transverse magnetic field between the anode and the cathode of the X-ray tube by the coil unit, the remaining free charged particles perform a spiral movement between the two electrodes under the action of a Lorentz force, thereby lengthening the movement path of the free charged particles and increasing the probability of collision between the free charged particles and the remaining gas molecules, which in turn provides increased measurability of the ion current for sensitive detection of a minute change in the ion current, improved measurement sensitivity, reduced technical requirements for the high voltage and the pulse width provided by the pulse voltage supply unit, and thus reduced design difficulty. Thus, a vacuum degree of 10 -4 Pa to 10 -1Pa, namely in a range of 10 -6 mbar to 10 -3 mbar, can be measured.

[0022] Another advantage of the present disclosure is that the vacuum level measuring apparatus, method, and system can be used in quality control during everyday production to detect product defects at an early stage and avoid causing significant rework time and wasteful materials during rework due to defective products being passed to downstream operations. This provides increased production efficiency and reduced costs. BRIEF DESCRIPTION OF THE CHARACTERS

[0023] Hereinafter, the preferred embodiments of the present disclosure will be described in more detail with reference to the figures so that the prescribed and other features and advantages of the invention will become more apparent to those skilled in the art. Fig. 1 is a block diagram of an apparatus for measuring the degree of vacuum of an X-ray tube according to an embodiment, Fig. 2 is a block diagram of the device for measuring the degree of vacuum of an X-ray tube according to another embodiment, Fig. 3 is a flowchart of a method for measuring the degree of vacuum of an X-ray tube according to an embodiment, Fig. 4 is a block diagram of a system for measuring the degree of vacuum of an X-ray tube according to an embodiment, Fig. 5 is a circuit diagram of the device for measuring the degree of vacuum of an X-ray tube according to an embodiment, Fig. 6 a schematic representation of a current-vacuum degree reference curve for measuring the vacuum degree of an X-ray tube according to an embodiment. DETAILED EMBODIMENTS

[0024] For a better understanding of the technical features, objects and effects of the present invention, specific embodiments of the invention will be described in more detail with reference to the accompanying drawings, wherein like reference numerals designate like parts throughout the individual drawings.

[0025] In the description, "schematic" means use as embodiments, examples, or explanations. The figures and embodiments explained "schematically" in the description should not be interpreted as a more preferred technical solution or a technical solution with more advantages.

[0026] For the sake of clarity, only those parts related to the invention are shown schematically in the respective drawings, which do not represent the actual structure of the respective product. Furthermore, in some drawings, for the sake of clarity, only one of the parts with the same structure or function is shown schematically or provided with reference symbols for better understanding.

[0027] Here, "a" does not mean "just one"; rather, "more than one" is conceivable. The terms "first," "second," etc., serve merely to distinguish them from one another and in no way indicate, among other things, the importance, order, or prerequisite for their existence in relation to one another.

[0028] The operating performance of an X-ray tube is closely related to the parameters of its vacuum environment. Insufficient vacuum within the X-ray tube is a common failure scenario during the manufacturing and use of an X-ray tube. An insufficient vacuum level significantly affects product performance and could cause sparking, oxidation of internal parts, shortened service life, and even failure, necessitating product scrapping. Especially for sealed X-ray tubes, a technique for non-destructive, accurate measurement of the internal vacuum level can often avoid reworking or scrapping the X-ray tube.

[0029] The present disclosure provides an apparatus for measuring the vacuum degree of an X-ray tube, in which the movement path of the electrons between the vacuum tube is extended by applying a magnetic field between a cathode and an anode of the X-ray tube. By measuring an ion current generated after ionization as a result of a collision between a portion of the free charged ions present in the residual gas in the vacuum tube of the X-ray tube and molecules of the remaining thin gas within the vacuum tube, the magnitude of a measurable ion current is determined by means of a measuring circuit. By comparing it with a current-vacuum degree reference curve, the vacuum degree of the X-ray tube can be determined. With such a method for measuring the vacuum degree of an X-ray tube, the vacuum degree of an X-ray tube can be measured non-destructively, quickly, and accurately.

[0030] Fig. 1 shows a block diagram of an apparatus for measuring the degree of vacuum of an X-ray tube according to an embodiment.

[0031] As can be seen from Fig. 1, the device 100 for measuring the degree of vacuum of an X-ray tube comprises: a pulse voltage supply unit 101 configured to apply a positive pulse voltage to the anode of an X-ray tube to be measured in order to generate a current resulting from ionization due to a collision between free charged particles present in a residual gas within the X-ray tube and remaining gas molecules; a measuring circuit unit 102 comprising a scanning module 1021, the scanning module 1021 being configured to measure the magnitude of the electric current at the cathode; and a processing unit 104 configured to compare the measured magnitude of the current with an a priori current-degree of vacuum reference curve and thus determine the degree of vacuum of the X-ray tube.

[0032] By applying a pulsed voltage to the anode of the X-ray tube being measured, a strong electric field (an electrostatic field) can be created between the cathode and the anode of the X-ray tube. The strong electric field can point from the anode to the cathode of the X-ray tube. Under the influence of the strong electric field, ionization occurs as a result of a collision between free charged particles present in the residual gas inside the X-ray tube and molecules of the remaining thin gas while moving in the electric field, generating electrons and ions and thus an electric current. The lower the degree of vacuum inside the X-ray tube, the higher the number of thin gas molecules inside the X-ray tube, so more electrons and ions are generated by the collision between the charged particles and the gas molecules, resulting in a larger electric current.

[0033] It should be noted that the current-vacuum degree reference curve can be determined in advance by using several X-ray tubes with different vacuum degrees as the X-ray tubes to be measured, wherein the X-ray tubes have specific vacuum degrees. By applying a positive pulse voltage to the X-ray tubes using the X-ray tube vacuum degree measuring device and measuring the electric current magnitude of the X-ray tubes, an a priori current-vacuum degree reference curve can be determined as a reference curve. Furthermore, discrete current values ​​generated by a collision between free charged particles and residual gas molecules are measured for several X-ray tubes with different vacuum degrees, and a continuous current-vacuum degree reference curve can be determined using a fitting algorithm and an interpolation algorithm, among others, to obtain a continuous current-vacuum degree reference curve.By using the current-vacuum degree reference curve, a corresponding vacuum degree value can be found based on the measured current value, thus confirming the vacuum degree of the X-ray tube. There is no limitation in this regard in the present embodiment.

[0034] The sampling module 1021 can measure the magnitude of the electric current, in particular a discrete value of the electric current, by sampling a current signal.

[0035] The processing unit 104 may include a memory that can store a current-vacuum degree reference curve. Furthermore, the processing unit may further include a display device 1041. The display device 1041 may display a vacuum degree value corresponding to the measured current value of the X-ray tube. Furthermore, the display device 1041 may further be configured to display the measured current value of the X-ray tube. Here, the processing unit 104 may be, among other things, a single-chip computer or a central microprocessor unit (MCU). There is no limitation in the present embodiment.

[0036] Fig. 2 shows a block diagram of the apparatus for measuring the degree of vacuum of an X-ray tube according to another embodiment.

[0037] As from Fig. 2, according to some embodiments, in order to increase the probability of a collision between the remaining free charged particles within the X-ray tube and the remaining gas molecules, and thus to extend the path of movement of the free charged particles in the X-ray tube, the device for measuring the degree of vacuum of an X-ray tube further comprises: a coil unit 103 comprising an excitation coil arranged between the cathode and the anode of the X-ray tube and applying a magnetic field in a direction transverse to the anode and pointing towards the cathode, so that the free charged particles as well as the electrons and ions generated by ionization of the gas molecules execute a spiral movement within a vacuum tube region between the cathode and the anode under the influence of the magnetic field. The generated electric current flows from the anode to the cathode.

[0038] According to some embodiments, the coil unit may comprise an excitation coil 1031. The excitation coil 1031 applies a magnetic field in a direction transverse to the anode and pointing toward the cathode, so that the free charged particles, under the influence of a Lorentz force, execute a spiral motion within a vacuum region of the X-ray tube. Furthermore, the magnetic field applied by the excitation coil 1031 can be understood to simultaneously run transversely to the direction of motion of the free charged particles under the influence of the electrostatic field.Thus, under the influence of the magnetic field applied by the excitation coil 1031, the probability of a collision between the charged particles and the gas molecules is increased, thus achieving a complete collision between the charged particles and the gas molecules within the X-ray tube, which allows the actual current to be determined and the degree of vacuum within the X-ray tube to be more accurately reflected. In some embodiments, multiple excitation coils 1031 may be provided, which may be arranged opposite one another between the cathode and the anode of the X-ray tube to apply a magnetic field in a direction transverse to the electric current direction.An advantage of the above configuration is that it reduces the requirement for the voltage and the pulse width of the pulse voltage applied by the pulse voltage supply unit 101, enables a clearer current signal, achieves improved noise immunity, and realizes a simpler and more accurate measurement of the actual current.

[0039] According to some embodiments, in order to apply a suitable strong electric field between the anode and the cathode of the X-ray tube by the pulse voltage supply unit 101, the pulse width of the pulse voltage may be between 20 and 100 ms and the voltage may be between 8 and 15 kV.

[0040] According to some embodiments, the pulse voltage supply unit 101 further comprises a pulse modulator for modulating the generated pulse voltage. The pulse modulator can modulate the pulse voltage such that the pulse width is between 20 and 100 ms and the voltage is between 8 and 15 kV.

[0041] Since the current-related signal generated by ionization resulting from a collision between the free charged particles in the residual gas within the X-ray tube and the molecules of the remaining thin gas is weak, according to some embodiments, to increase the measurement sensitivity, the measurement circuit unit 102 further comprises an amplifier 1024. The amplifier 1024 is configured to amplify the current-related signal. The sampling module 1021 is configured to acquire the amplified signal to obtain a discrete current value related to the current.

[0042] According to some embodiments, the measuring circuit unit 102 can be powered by a separate power supply to measure the value of the electrical current through the measuring circuit unit 102 and to avoid interference with a pulse voltage and a high-voltage signal when sampling the current and measuring the current value, thus increasing the accuracy and robustness of the measured current. To this end, the measuring circuit unit 102 further comprises a first power supply 1022 and the sampling module 1021. The first power supply 1022 is connected to the sampling module 1021 and configured to supply power to the sampling module 1021. The first power supply 1022 is configured to be electromagnetically isolated at least from the pulse voltage supply unit 101. The sampling module 1021 includes an ammeter 1023 for measuring the current at the cathode.For this purpose, the first power supply 1022 can be arranged in an electromagnetically shielded housing in order to avoid signal interference of the pulse voltage supply unit 101 in the high voltage range.

[0043] According to some embodiments, the magnetic field applied by the excitation coil 1031 has a magnetic flux density of 0.2 T to 0.3 T, so as to achieve that the excitation coil 1031 generates a magnetic field with a suitable magnetic flux density and the free charged particles in the residual gas of the X-ray tube move along a spiral movement track when moving in the X-ray tube, thereby causing complete ionization due to an increased probability of collision between the free charged particles and the gas molecules to faithfully reflect the degree of vacuum of the X-ray tube.

[0044] According to some embodiments, in order to generate a magnetic field with a suitable magnetic flux density through the excitation coil 1031, the excitation coil 1031 is supplied with a specific voltage, which can therefore be determined, among other things, as a function of the magnetic flux density of the magnetic field and the number of turns of the excitation coil 1031. For this purpose, the coil unit 103 further comprises a second power supply 1032, which is connected to the excitation coil 1031 and supplies the excitation coil 1031 with power. The second power supply 1032 can provide a suitable and stable voltage value, which can be approximately between 100 V and 1,000 V. Therefore, the excitation coil 1031 should be supplied with power separately by the second power supply 1032.

[0045] Since the pulse voltage supply unit 101 and the second power supply 1032 operate at a high voltage value and thus pose a certain risk, the device for measuring the degree of vacuum of an X-ray tube according to some embodiments optionally further comprises a protection circuit 105, wherein the protection circuit 105 may comprise at least one switch 1051, wherein the switch 1051 is configured to be connected at least to the pulse voltage supply unit 101 and a current input of the second power supply 1032 in order to trigger the switching on and off of the pulse voltage supply unit 101 and the second power supply 1032. A specific trigger condition and a specific scenario may be provided to trigger the switching off of the pulse voltage supply unit 101 and the second power supply 1032.For example, when measuring the degree of vacuum of the X-ray tube to be measured, it may be determined that, in an open environment, a positive pulse voltage is applied to the anode of the X-ray tube to be measured by the pulse voltage supply unit 101 and / or a certain high voltage is applied to the excitation coil 1031 by the second power supply 1032. The triggering of the switching off and on of the switch 1051 can be achieved via a relay.

[0046] According to another aspect of the present disclosure, a method for measuring the degree of vacuum of an x-ray tube is further provided.

[0047] Fig. 3 shows a flowchart of a method for measuring the degree of vacuum of an X-ray tube according to an embodiment.

[0048] As can be seen from Fig. 3, the method for measuring the degree of vacuum of an X-ray tube includes: S201: Applying a positive pulse voltage to an anode of an X-ray tube to be measured by means of a pulse power supply in order to generate a current resulting from ionisation as a result of a collision between free charged particles present in a residual gas within the X-ray tube and molecules of the remaining thin gas. S202: Applying a magnetic field between the cathode and the anode of the X-ray tube in a direction transverse to the anode and pointing towards the cathode. S203: Comparing the measured electric current with an a priori current-vacuum degree reference curve to determine the vacuum degree of the X-ray tube.

[0049] It should be noted that the current-vacuum degree reference curve can be determined in advance by using multiple X-ray tubes with different vacuum degrees as the X-ray tube to be measured, wherein the X-ray tubes have specific vacuum degree values. Through the above steps S201 to S203, the magnitude of the electric current is measured for each of multiple X-ray tubes with different known vacuum degrees. Due to a positive pulse voltage applied to the anode of the X-ray tube, a strong electric field is generated, so that the free charged particles remaining within the X-ray tube move under the action of the electric field and generate the electric current through ionization due to collision with the remaining gas molecules. By measuring the current value, an a priori current-vacuum degree reference curve is determined / created as a reference curve based on the corresponding known vacuum degree values.Based on the above discrete current-vacuum degree values, a continuous current-vacuum degree reference curve is obtained using, among other things, the fitting algorithm and the interpolation algorithm. A detailed description of this is omitted here.

[0050] According to another aspect of the present disclosure, a system for measuring the degree of vacuum of an x-ray tube is further provided.

[0051] Fig. 4 shows a system for measuring the degree of vacuum of an X-ray tube according to an embodiment.

[0052] As from Fig. As can be seen from Figure 4, the system 300 for measuring the degree of vacuum of the X-ray tube 301 comprises a device 100 for measuring the degree of vacuum of the X-ray tube 301 and the X-ray tube 301, which includes a cathode (wire) 303, an anode 305, and a housing portion 307 that encloses the cathode and anode. The cathode 303 may include a cathode wire.

[0053] In the device 100 for measuring the degree of vacuum of the X-ray tube 301, a positive pole of the pulse voltage supply unit is connected to the anode 305 of the X-ray tube 301, while a negative pole of the pulse voltage supply unit is connected to the cathode (wire) 303 of the X-ray tube 301. After the pulse voltage supply unit supplies the anode 305 of the X-ray tube 301 with a positive pulse voltage, a strong electric field is applied between the cathode 303 and the anode 305 of the X-ray tube 301, so that ionization occurs due to a collision between the free charged particles present in the residual gas inside the X-ray tube 301 and the remaining gas molecules, thereby generating electrons and ions.The electric current thus generated flows in the direction of the cathode, so that the electric current at the cathode can be measured and thus the vacuum level of the X-ray tube 301 can be determined by comparing / searching against the current-vacuum level reference curve.

[0054] Thus, without destroying the X-ray tube 301, a strong electric field is created between the cathode and the anode within the X-ray tube by means of the positive pulse voltage applied to the anode, causing ionization due to collisions between the free charged particles in the residual gas and the remaining gas molecules. Thus, the vacuum level of the X-ray tube 301 can be determined solely by measuring the current value resulting from ionization at the anode of the X-ray tube 301, which provides significant economic advantages. Furthermore, the above measurement method imposes no restrictions on the material of the X-ray tube casing. Thus, the casing material can include, but is not limited to, metal, glass, and ceramic.

[0055] According to some illustrated embodiments, a safety switch is to be provided for the pulse voltage supply unit and the second power supply 1032 in order to ensure user safety during the measurement of the vacuum level of the X-ray tube 301. To this end, the system 300 for measuring the vacuum level of an X-ray tube further comprises a protective cabinet configured to accommodate the X-ray tube 301 and the device 100 for measuring the vacuum level of an X-ray tube, wherein the protective cabinet has a protective cabinet door that serves as a safety switch of the system. The protective cabinet door is connected to a protective circuit that includes a switch 1051. The switch 1051 acts at least on the pulse voltage supply unit 101 and a current input of the second power supply 1032.The switch 1051 is configured to trigger the switching off of the pulse voltage supply unit 101 and the second power supply 1032 when the protective cabinet door is opened, and to trigger the switching on of the pulse voltage supply unit 101 and the second power supply 1032 when the protective cabinet door is closed. Opening the protective cabinet door thereby connects the X-ray tube 301 and the device 100 for measuring the degree of vacuum of an X-ray tube, which are arranged inside the protective cabinet, to the outside environment, while closing the protective cabinet door corresponds to sealing the protective cabinet from the outside environment.Furthermore, to ensure the locking of the protective cabinet by the protective cabinet door during the measurement of the vacuum level of the X-ray tube 301, the protective cabinet may further comprise an electromagnetic lock (not shown) that acts on the protective cabinet door and can be configured to be triggered and lock the protective cabinet door, thus ensuring the locking of the protective cabinet when, after triggering the switching on of the pulse voltage supply unit 101 and the second power supply 1032 by the switch 1051 and after supplying the pulse voltage supply unit 101 and the second power supply 1032 with an alternating voltage, the device 100 for measuring the vacuum level of an X-ray tube starts a measurement of the vacuum level of the X-ray tube 301. The triggering of the switching off and switching on of the switch 1051 may also be achieved via a relay.

[0056] Furthermore, the pulse voltage supply unit 101 and the power input end of the second power supply 1032 can receive an AC voltage of 220 V. Here, a 220 V AC voltage can be fed into the pulse voltage supply unit 101 and the second power supply 1032 via a neutral conductor N and a live conductor L arranged in pairs. In the present embodiment, a detailed description of this is omitted.

[0057] Fig. 5 shows a circuit diagram of the device for measuring the degree of vacuum of an X-ray tube according to an embodiment.

[0058] As from Fig. As can be seen from Figure 5, the pulse voltage supply unit 101 and the X-ray tube 301, whose vacuum level is to be measured, form a circuit. Specifically, the positive pole of the pulse voltage supply unit 101 is connected to the anode 305 of the X-ray tube 301, while the negative pole of the pulse voltage 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 within the X-ray tube 301 are caused to move under the influence of a strong electric field. Ionization occurs as a result of a collision with the remaining gas molecules during the movement. The ionizing particles generate an observable electric current, which is used to determine the vacuum level within the X-ray tube.

[0059] In addition, the second power supply 1032, the X-ray tube 301, whose vacuum level is to be measured, and the excitation coil 1031 form another circuit. The second power supply 1032 can be connected to the excitation coil 1031 via a power cable and feed a specific high voltage into the excitation coil 1031. Specifically, the excitation coil 1031 can be arranged between the cathode and the anode of the X-ray tube and apply a magnetic field in a direction perpendicular to the direction of movement of the free charged particles, so that the free charged particles, under the influence of the magnetic field, perform a spiral movement within a region of the cathode and the anode. In this case, several excitation coils 1031 can be arranged opposite one another between the cathode and the anode of the X-ray tube 301. For this purpose, the second power supply 1032 can feed a high voltage into the respective excitation coils 1031 via several power cables.The high voltage provided by the second power supply 1032 can cause the generation of a magnetic field of 0.2 T to 0.3 T from the excitation coil 1031, so that an electric current associated with ionization is generated by a complete collision between the free charged particles and the remaining gas molecules, thus achieving an accurate measurement of the degree of vacuum.

[0060] Furthermore, the measuring circuit unit 102 can be connected to the cathode 303 of the X-ray tube 301 to be measured in order to measure, via the scanning module 1021, the magnitude of the observable electric current generated by the ionization resulting from the collision between the free charged particles and the gas molecules. Specifically, a discrete current value of the electric current is detected via the scanning module 1021. Here, the scanning module 1021 includes an ammeter 1023, and the ammeter 1023 can be connected to the cathode of the X-ray tube 301 in series with it to measure the current value of the electric current.

[0061] Furthermore, the protection circuit 105 and a protective cabinet accommodating the X-ray tube 301 and the device 100 for measuring the vacuum level of an X-ray tube can form a protective circuit. According to an illustrated embodiment, the protection circuit 105 can be connected to the protective cabinet door, which can serve as a safety switch, so that the opening and closing of the protective cabinet door serve as a trigger condition to cause the pulse voltage supply unit 101 and the second power supply 1032 to be switched on and off by the protection circuit 105, thus ensuring measurement safety for the user. Specifically, the protection circuit 105 can include at least one switch 1051.The switch 1051 is connected at least to the pulse voltage supply unit 101 and the current input of the second power supply 1032 to trigger the switching on and off of the pulse voltage supply unit 101 and the second power supply 1032. Furthermore, the switching off of the pulse voltage supply unit 101 and the second power supply 1032 is triggered when the protective cabinet door is opened.Furthermore, to ensure the locking of the protective cabinet by the protective cabinet door during the measurement of the vacuum level of the X-ray tube 301, the protective cabinet may further comprise an electromagnetic lock (not shown) that acts on the protective cabinet door and can be configured to be triggered and lock the protective cabinet door, thus ensuring the locking of the protective cabinet when, after triggering the switching on of the pulse voltage supply unit 101 and the second power supply 1032 by the switch 1051 and after supplying the pulse voltage supply unit 101 and the second power supply 1032 with an alternating voltage, the device 100 for measuring the vacuum level of an X-ray tube starts a measurement of the vacuum level of the X-ray tube 301. The triggering of the switching off and switching on of the switch 1051 may also be achieved via a relay.

[0062] Fig. 6 shows a schematic representation of a current-vacuum degree reference curve for measuring the vacuum degree of an X-ray tube according to an embodiment.

[0063] As can be seen from Fig. 6, the current-vacuum degree reference curve can be obtained by measuring a plurality of X-ray tubes with different vacuum degrees by the X-ray tube vacuum degree measuring device 100. Specifically, the measurement environment of the X-ray tube vacuum degree measuring device 100 can be configured as follows: The pulse voltage supply unit 101 can supply a pulse voltage with a voltage of 8 to 15 kV and a pulse width of 20 to 100 ms. The second power supply 1032 can supply a suitable voltage approximately 100 to 1000 V, so that the excitation coil 1031 can generate a magnetic field of 0.2 T to 0.3 T.

[0064] As can be seen from the current-vacuum degree reference curve according to Fig.As can be seen from Figure 6, under the above measurement conditions there is a precise and unambiguous correlation between the degree of vacuum in the range of 10 -7 mbar to 10 3 mbar and the current value, with the precisely assigned current value being in the range from 10 µA to 10,000 µA.

[0065] In the above embodiments of the present application, individual embodiments with different focuses were described. For parts not explained in detail in a specific embodiment, reference can be made to the description of other embodiments.

[0066] In the embodiments of the present application, it is understood that the disclosed technical content can be implemented in other ways. The above device embodiments have been described only schematically. For example, the subdivision of the units or modules is based solely on their logical functions. In practical implementation, the subdivision can be implemented in other ways. For example, several units, modules, or assemblies can be combined with one another or integrated into another system. Alternatively, some features can be omitted or need not be implemented.

[0067] Furthermore, in the embodiments of the present application, individual functional units can be integrated into a processing unit or module, alternatively, they can be physically separate, or they can be integrated two or more at a time into a unit or module. The integrated units or modules can be implemented both in the form of hardware and as software functional units or modules.

[0068] Thus far, only preferred embodiments of the present application have been explained. It should be noted that various improvements and modifications are possible for those of ordinary skill in the art without departing from the principle of the present application, which should also be considered within the scope of the application. List of reference symbols: 100 Device for measuring the degree of vacuum of an X-ray tube 101 Pulse voltage supply unit 102 Measuring circuit unit 1021 scanning module 1022 first power supply 1023 ammeters 1024 amplifiers 103 Coil unit 1031 Excitation coil 1032 second power supply 104 processing unit 1041 Display device 105 Protection circuit 1051 switches 300 System for measuring the degree of vacuum of an X-ray tube 301 X-ray tube 303 Cathode 305 Anode 307 Housing section

Claims

[1] Device for measuring the degree of vacuum of an X-ray tube, characterized by that it includes: a pulse voltage supply unit (101) configured to apply a positive pulse voltage to an anode of an X-ray tube to be measured in order to generate a current resulting from ionization as a result of a collision between free charged particles present in a residual gas within the X-ray tube and remaining gas molecules, a measuring circuit unit (102) comprising a sampling module (1021), wherein the sampling module (1021) is configured to measure the magnitude of the current at the cathode, and to compare the magnitude of the current with an a priori current-vacuum degree reference curve and thus determine the vacuum degree of the X-ray tube. [2] Apparatus for measuring the degree of vacuum of an X-ray tube according to claim 1, characterized by that it also includes: a coil unit (103) comprising an excitation coil (1031), wherein the excitation coil (1031) is arranged between the cathode and the anode of the X-ray tube and applies a magnetic field in a direction transverse to the anode and pointing towards the cathode, so that the free charged particles execute a spiral movement within a closed region between the cathode and the anode under the action of the Lorentz force. [3] An X-ray tube vacuum degree measuring device according to claim 1 or 2, wherein the pulse width of the pulse voltage is between 20 and 100 ms and the voltage is between 8 and 15 kV. [4] An X-ray tube vacuum degree measuring device according to any one of claims 1-3, wherein the pulse voltage supply unit (101) further comprises a pulse modulator for generating the pulse voltage. [5] The apparatus for measuring the degree of vacuum of an X-ray tube according to any one of claims 1-4, wherein the measuring circuit unit (102) further comprises an amplifier configured to amplify a signal associated with the current, and wherein the sampling module (1021) is configured to sample the amplified signal to obtain a current value of the current. [6] The apparatus for measuring the degree of vacuum of an X-ray tube according to any one of claims 1-5, wherein the measuring circuit unit (102) further comprises a first power supply (1022) and the scanning module (1021) comprises an ammeter (1023), the first power supply (1022) being connected to the scanning module (1021) and configured to supply power to the scanning module (1021), the first power supply (1022) being configured to be electromagnetically isolated at least from the pulse voltage supply unit (101). [7] An X-ray tube vacuum degree measuring apparatus according to any one of claims 2-6, wherein the magnetic field applied by the excitation coil (1031) has a magnetic flux density of 0.2 T to 0.3 T. [8] An apparatus for measuring the degree of vacuum of an X-ray tube according to any one of claims 2-7, wherein the coil unit (103) further comprises: a second power supply (1032) connected to the excitation coil (1031) and supplying power to the excitation coil (1031). [9] Apparatus for measuring the degree of vacuum of an X-ray tube according to claim 8, characterized by that it also includes: a protection circuit (105) comprising a switch connected at least to the pulse voltage supply unit (101) and a current input of the second power supply (1032) in order to trigger the switching on and off of the pulse voltage supply unit (101) and the second power supply (1032). [10] Method for measuring the degree of vacuum of an X-ray tube, characterized by that it includes: Applying a positive voltage to an anode of an X-ray tube to be measured by means of a pulsed voltage supply in order to generate a current resulting from ionisation as a result of a collision between free charged particles present in a residual gas within the X-ray tube and remaining gas molecules; Applying a magnetic field between the cathode and the anode of the X-ray tube in a direction transverse to the anode and pointing towards the cathode; and Comparing the measured current magnitude with an a priori current-vacuum degree reference curve to determine the vacuum degree of the X-ray tube. [11] System for measuring the degree of vacuum of an X-ray tube, characterized by that it includes: a device for measuring the degree of vacuum of an X-ray tube according to 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] System for measuring the degree of vacuum of an X-ray tube according to claim 11, characterized bythat it further comprises a protective cabinet configured to accommodate the X-ray tube (301) and the device (100) for measuring the degree of vacuum of an X-ray tube, wherein the protective cabinet has a protective cabinet door serving as a safety switch of the system, wherein the protective cabinet door is connected to a protective circuit (105) comprising a switch connected at least to the pulse voltage supply unit and a current input of a second power supply connected to an excitation coil and supplying current to the excitation coil, wherein the switch is configured to trigger the switching off of the pulse voltage supply unit and the second power supply when the protective cabinet door is opened and to trigger the switching on of the pulse voltage supply unit and the second power supply when the protective cabinet door is closed,and wherein the excitation coil is arranged between the cathode and the anode of the X-ray tube and applies a magnetic field in a direction transverse to the anode and pointing towards the cathode.,

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