Miniature cathode-less X-ray generator for space X-ray detector calibration

Abstract

The present invention belongs to the technical field of X-ray tube sources, and in particular relates to a miniature cathodeless X-ray generator for calibrating space X-ray detectors, comprising: a high-voltage transformer (1), a high-voltage multiplier rectifier (2), a miniature cathodeless X-ray tube (3) and a structural shielding box (5); the high-voltage transformer (1) is electrically connected to the high-voltage multiplier rectifier (2), and the high-voltage multiplier rectifier (2) is electrically connected to the miniature cathodeless X-ray tube (3); the high-voltage transformer (1), the high-voltage multiplier rectifier (2) and the miniature cathodeless X-ray tube (3) are all arranged in the structural shielding box (5) and are potted with high-voltage insulating potting glue (4) to form a sealed structure.

Description

Technical Field

[0001] The present invention belongs to the technical field of X-ray tube sources, and in particular relates to a miniature cathodeless X-ray generator for calibrating space X-ray detectors. Background Art

[0002] X-ray astronomy is a discipline that uses X-rays to conduct astrophysical research. X-rays from celestial bodies are absorbed and attenuated by the Earth's atmosphere. Therefore, X-ray detection requires satellite platforms in space. To accurately determine the energy spectrum of X-rays from celestial bodies, precise on-orbit calibration of X-ray detectors is required. This includes calibration of the detector's linearity, energy resolution, gain, and the temporal evolution of these parameters.

[0003] At present, the calibration of space X-ray detectors mainly relies on portable radioactive sources. For example, the proportional counter (PCA) on the Rossi X-ray Timing Detector (RXTE) satellite and the High Energy X-ray Timing Detector (HEXTE) satellite both carry 241 Am radioactive source, Am 241 During the decay process, high-energy X-rays of 59.5keV, 26.35keV, and 13.9keV are emitted. 241 Ammonium is a good choice for calibrating hard X-ray detectors. In addition, the X-ray spectrometer on my country's Chang'e 2 satellite also carries 1μCi 55 Fe radioactive source, used to monitor the performance changes of the X-ray spectrometer on orbit. 55 Fe emits 5.899keV Mn-K during decay α rays and 6.497keV Mn-K β These two monoenergetic spectral lines can be used to calibrate detector gain and linearity, as well as their temporal variations. While onboard radioactive sources can calibrate X-ray detectors on satellites, the continuous X-ray emission from these sources in orbit introduces a high noise floor to the detectors, impacting the quality of scientific data. Furthermore, radioactivity poses a health hazard to humans, posing a risk of ionization damage to non-professionals. Therefore, the use of radioactive sources onboard space instruments is strictly controlled, and in many cases, onboard calibration of satellite X-ray detectors is foregone.

[0004] Therefore, the existing X-ray detectors have certain limitations in the on-orbit radioactive source calibration, and have the problems of large size, heavy weight, high power consumption and short life.

[0005] In view of this situation, the present invention provides a cathode-free micro X-ray closed tube that can provide K-ray X-rays of tungsten target and manganese target. αOr characteristic X-rays from other target materials meet the requirements for on-orbit calibration of space X-ray detectors. Furthermore, the micro X-ray tube lacks an electron-emitting cathode and relies on leakage current across a negative high voltage to generate X-rays, preventing the cathode filament from burning out. Furthermore, the micro X-ray tube generates X-rays only when calibration is required, eliminating background noise in the detector and the risk of ionization damage to non-professionals. Therefore, the present invention overcomes the limitations of existing radioactive source calibration methods for on-orbit X-ray detectors, offering advantages such as small size, light weight, low power consumption, and long life, making it a viable alternative to on-orbit radioactive source calibration methods. Summary of the Invention

[0006] In order to solve the above-mentioned defects of the prior art, the present invention proposes a miniature cathodeless X-ray generator for space X-ray detector calibration. The X-ray generator is a miniature cathodeless X-ray tube, which serves as a long-life, low-power miniature X-ray generator for space X-ray detector energy spectrum calibration.

[0007] The present invention provides a miniature cathodeless X-ray generator for calibrating space X-ray detectors, which comprises: a high-voltage transformer, a high-voltage multiplier rectifier, a miniature cathodeless X-ray tube and a structural shielding box;

[0008] The high-voltage transformer is electrically connected to the high-voltage multiplier rectifier, and the high-voltage multiplier rectifier is electrically connected to the miniature cathodeless X-ray tube;

[0009] The high-voltage transformer, high-voltage multiplier rectifier and miniature cathodeless X-ray tube are all arranged in a structural shielding box and are potted with high-voltage insulating potting glue to form a sealed structure; among them, the grounding electrode in the miniature cathodeless X-ray tube passes through the opening opened on the structural shielding box, extends outward from the opening, and is connected to the structural shielding box; the high-voltage electrode in the miniature cathodeless X-ray tube is encapsulated in the high-voltage insulating potting glue.

[0010] As one of the improvements of the above technical solution, the high-voltage transformer and the high-voltage multiplier rectifier together constitute a high-voltage power supply, which is connected to the high-voltage pole of the miniature cathodeless X-ray tube.

[0011] As one of the improvements to the above technical solution, the high-voltage multiplier rectifier adopts a Cockcroft-Walton circuit in a ladder-shaped structure, which specifically includes: a first cylindrical capacitor component, a second cylindrical capacitor component, a plurality of first cylindrical diodes, and a plurality of second cylindrical diodes;

[0012] The first cylindrical capacitor component and the second cylindrical capacitor component serve as waists of the ladder structure, and the plurality of first cylindrical diodes and the plurality of second cylindrical diodes serve as beams of the ladder structure;

[0013] The first cylindrical capacitor assembly and the second cylindrical capacitor assembly are both composed of a plurality of cylindrical capacitors stacked and welded together in series; there are equally spaced welds between the cylindrical capacitors, each first cylindrical diode and each second cylindrical diode are relatively parallel welded on both sides of the weld of the cylindrical capacitor, and each first cylindrical diode and each second cylindrical diode are relatively cross-arranged.

[0014] As one of the improvements of the above technical solution, the miniature cathodeless X-ray tube is a cathodeless X-ray closed tube suitable for space use, which includes: a high-voltage electrode, a sealed ceramic, a ground electrode and a ray target;

[0015] The sealing ceramic is a hollow cylindrical structure, with a high-voltage electrode and a grounding electrode placed at either end of the sealing ceramic. The high-voltage electrode is a disc structure, and the grounding electrode is a ring structure, and is connected to the ground of the high-voltage power supply. The target is placed in the center of the grounding electrode ring, with its metal-coated surface placed inside the X-ray tube, opposite the high-voltage electrode.

[0016] The high voltage electrode, sealing ceramic, ground electrode and target are brazed together by vacuum, and the atmospheric pressure inside is 10 -1 to 10 -3 Between Pa;

[0017] When the high-voltage electrode is connected to a negative DC high voltage, the residual gas in the tube discharges, and eventually the electrons hit the target to produce X-rays.

[0018] As one of the improvements of the above technical solution, the high-voltage electrode is made of Kovar steel material and has a disc-shaped structure with uniform thickness, and its thickness is 0.5-2 mm.

[0019] As one of the improvements of the above technical solution, the sealing ceramic is alumina ceramic, which is used to isolate the high voltage electrode and the grounding electrode, and the height of the sealing ceramic is between 5-20 mm.

[0020] As one of the improvements of the above technical solution, the grounding electrode is made of an annular Kovar steel material with uniform thickness, and the thickness is in the range of 0.5-2 mm.

[0021] As one of the improvements of the above technical solution, the substrate of the ray target is a beryllium sheet, and tungsten is plated on either side of the beryllium sheet to generate X-rays. The coating thickness is greater than 0.1 micron; the thickness of the beryllium sheet is greater than 0.2 mm.

[0022] The beneficial effects of the present invention compared with the prior art are:

[0023] 1. The cathodeless miniature X-ray closed tube of the present invention can provide characteristic X-rays of tungsten target K-ray series, manganese target K-ray series, or other target materials, meeting the on-orbit calibration requirements of space X-ray detectors. Moreover, the miniature cathodeless X-ray tube does not have an electron emission cathode and relies on leakage current at both ends of the negative high voltage to generate X-rays, which will not cause the cathode filament to burn out.

[0024] 2. The micro X-ray device generates X-rays only when calibration is required, which does not generate background noise for the detector and does not pose the risk of ionization damage to non-professionals. It overcomes the limitations of existing X-ray detectors calibrated with on-orbit radioactive sources and has the advantages of small size, light weight, low power consumption, and long life, making it a substitute for on-orbit radioactive source calibration. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a schematic structural diagram of a miniature cathodeless X-ray generator for calibrating space X-ray detectors according to the present invention;

[0026] Figure 2 This is a schematic structural diagram of a Cockcroft-Walton high-voltage multiplier rectifier in a miniature cathodeless X-ray generator for calibrating space X-ray detectors according to the present invention;

[0027] Figure 3 The present invention is a schematic structural diagram of a miniature cathodeless X-ray tube in a miniature cathodeless X-ray generator for calibrating a space X-ray detector.

[0028] Reference numerals:

[0029] 1. High-voltage transformer 2. High-voltage multiplier rectifier

[0030] 3. Micro cathodeless X-ray tube 4. High-voltage insulation potting compound

[0031] 5. Structural shielding box 6. Columnar capacitor

[0032] 7. Welding seam of cylindrical capacitor 8. First cylindrical diode

[0033] 9. Second cylindrical diode 10. High voltage pole

[0034] 11. Sealing ceramic 12. Grounding electrode

[0035] 13. Radiation target DETAILED DESCRIPTION

[0036] The present invention will now be further described with reference to the accompanying drawings and examples.

[0037] like Figure 1As shown, the present invention provides a miniature cathodeless X-ray generator for space X-ray detector calibration, specifically a miniature cathodeless X-ray tube for space X-ray detector energy spectrum calibration, which can provide K-line series X-rays of tungsten target and K-line series X-rays of manganese target. α The miniature X-ray tube, which produces characteristic X-rays from other target materials, meets the requirements for on-orbit calibration of space X-ray detectors. Furthermore, the miniature X-ray tube lacks an electron-emitting cathode and relies on leakage current across a negative high voltage to generate X-rays, preventing the cathode filament from burning out. Furthermore, the miniature X-ray tube generates X-rays only when calibration is required, eliminating background noise in the detector and the risk of ionization damage to non-professionals. Therefore, the generator of the present invention overcomes the limitations of existing radioactive source calibration methods for on-orbit X-ray detectors, offering advantages such as small size, light weight, low power consumption, long life, and high safety, making it a viable alternative to on-orbit radioactive source calibration.

[0038] like Figure 1 As shown, the present invention provides a miniature cathodeless X-ray generator for space X-ray detector calibration, which includes: a high-voltage transformer 1, a high-voltage multiplier rectifier 2, a miniature cathodeless X-ray tube 3 and a structural shielding box 5;

[0039] The high-voltage transformer 1 is electrically connected to the high-voltage multiplier rectifier 2, and the high-voltage multiplier rectifier 2 is electrically connected to the miniature cathodeless X-ray tube 3;

[0040] The high-voltage transformer 1, the high-voltage multiplier rectifier 2, and the micro cathodeless X-ray tube 3 are all arranged in a structural shielding box 5 and are potted with a high-voltage insulating potting compound 4 to form a sealed structure. Among them, the grounding electrode 12 in the micro cathodeless X-ray tube 3 passes through an opening in the structural shielding box, extends outward from the opening, and is connected to the structural shielding box 5. The high-voltage electrode 10 in the micro cathodeless X-ray tube 3 is encapsulated in the high-voltage insulating potting compound 4.

[0041] Among them, the high-voltage transformer 1 and the high-voltage multiplier rectifier 2 together constitute a high-voltage power supply. The high-voltage transformer 1 modulates the low-voltage DC power supply from the battery or other low-voltage DC power supply into an AC high-voltage power supply of hundreds to thousands of volts, and transmits the AC high-voltage power supply to the high-voltage multiplier rectifier 2. After further amplification and rectification by the high-voltage multiplier rectifier 2, it becomes a DC high-voltage power supply of more than 10,000 volts. The high-voltage DC power supply is connected to the high-voltage pole 10 of the miniature cathodeless X-ray tube 3.

[0042] like Figure 2 As shown, the high-voltage multiplier rectifier 2 adopts the Cockcroft-Walton circuit form and has a ladder-shaped structure, which specifically includes: a first cylindrical capacitor component, a second cylindrical capacitor component, a plurality of first cylindrical diodes 8 and a plurality of second cylindrical diodes 9;

[0043] The first cylindrical capacitor assembly and the second cylindrical capacitor assembly serve as the waist of the ladder structure, and the plurality of first cylindrical diodes 8 and the plurality of second cylindrical diodes 9 serve as the crossbeams of the ladder structure;

[0044] The first cylindrical capacitor assembly and the second cylindrical capacitor assembly are both composed of a plurality of cylindrical capacitors 6 stacked and welded together in series; there are equally spaced cylindrical capacitor welds 7 between the cylindrical capacitors 6, and each first cylindrical diode 8 and each second cylindrical diode 9 are relatively parallel welded on both sides of the cylindrical capacitor weld 7, and each first cylindrical diode 8 and each second cylindrical diode 9 are relatively cross-arranged.

[0045] like Figure 2 As shown in the figure, in order to achieve miniaturization, the capacitors in the Cockcroft-Walton circuit are cylindrical capacitors 6. When welding, the various components in the Cockcroft-Walton circuit adopt a ladder-shaped structure layout. The two sides of the ladder structure adopt a series stacking welding method to weld multiple cylindrical capacitors selected. The two sides of the ladder structure use the same number of cylindrical capacitors and the welding height is kept equal. Figure 2 In the middle, 6 is a cylindrical capacitor, and 7 is a weld between the cylindrical capacitors.

[0046] The diodes in the Cockcroft-Walton circuit are cylindrical diodes with pin-shaped pins. The cylindrical diodes act as the crossbars of the ladder structure of the Cockcroft-Walton circuit. They are evenly distributed along the front and back sides of the waist of the ladder structure and welded in parallel. The two pin-shaped pins of the diodes are welded to the weld seams 7 of the corresponding cylindrical capacitors on the two waists. Figure 2 Reference numeral 8 represents the first cylindrical diode on the front, and reference numeral 9 represents the second cylindrical diode on the back, arranged crosswise. This welding method ensures the overall structural stability of the high-voltage multiplier rectifier without a circuit board, while significantly reducing the volume of the Cockcroft-Walton circuit and achieving miniaturization. The high-voltage multiplier rectifier can increase the number of stages to meet specific needs, and the polarity of the output high voltage can also be adjusted by changing the grounding method.

[0047] like Figure 3 As shown, the miniature cathodeless X-ray tube 3 is a cathodeless X-ray closed tube suitable for space use, which includes: a high-voltage electrode 10, a sealing ceramic 11, a grounding electrode 12 and a ray target 13;

[0048] The sealing ceramic 11 is a hollow cylindrical structure, with a high-voltage electrode 10 and a ground electrode 12 placed at either end of the sealing ceramic 11. The high-voltage electrode 10 is a disc-shaped structure, and the ground electrode is a ring-shaped structure, and is connected to the ground of the high-voltage power supply. The radiation target 13 is placed in the center of the ring of the ground electrode 12, with its metal-coated surface placed inside the X-ray tube, opposite the high-voltage electrode 10.

[0049] The high voltage electrode 10, the sealing ceramic 11, the ground electrode 12 and the radiation target 13 are brazed together by vacuum, and the atmospheric pressure inside is 10 -1 to 10 -3 Between Pa;

[0050] When the high-voltage electrode 10 is connected to a negative DC high voltage, the residual gas in the tube is discharged, and eventually the electrons hit the radiation target 13 to generate X-rays.

[0051] like Figure 3 As shown, the high-voltage electrode 10 is made of Kovar steel and has a disc-shaped structure with uniform thickness of 0.5-2 mm. The high-voltage electrode 10 needs to be connected to an external DC negative high voltage.

[0052] The sealing ceramic 11 is made of aluminum oxide ceramic and is mainly used to isolate the high voltage electrode 10 and the ground electrode 12. The sealing ceramic 11 is a hollow cylindrical structure with a height of 5-20 mm.

[0053] The grounding electrode 12 is made of an annular Kovar steel material with uniform thickness, and its thickness is within the range of 0.5-2 mm. The grounding electrode 12 is connected to the ground of the high voltage power supply.

[0054] The substrate of the radiation target 13 is a beryllium sheet, and tungsten or other metal materials are plated on either side of the beryllium sheet to generate X-rays. The coating thickness is greater than 0.1 micron. The thickness of the beryllium sheet is greater than 0.2 mm, and the diameter is determined according to needs, generally greater than 3 mm.

[0055] like Figure 3 As shown, the ray target 13 is placed in the center of the ground electrode 12 , and the side coated with the metal film is placed inside the X-ray tube and opposite to the high-voltage electrode 10 .

[0056] The structural shielding box 5 is used to place the high-voltage transformer 1, the high-voltage multiplier rectifier 2 and the miniature cathodeless X-ray tube 3, and high-voltage insulating glue or high-voltage insulating oil is poured into the structural shielding box 5 to prevent high voltage from discharging with the air or the shielding shell. The outer shell of the structural shielding box is aluminum alloy or other metals and is connected to the power ground.

[0057] Finally, it should be noted that the above embodiments are intended only to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions to the technical solutions of the present invention do not depart from the spirit and scope of the technical solutions of the present invention and are intended to be encompassed by the claims of the present invention.

Claims

1. A miniature cathodeless X-ray generator for space X-ray detector calibration, characterized in that: It comprises: a high-voltage transformer (1), a high-voltage multiplier rectifier (2), a miniature cathodeless X-ray tube (3) and a structural shielding box (5); The high-voltage transformer (1) is electrically connected to the high-voltage multiplier rectifier (2), and the high-voltage multiplier rectifier (2) is electrically connected to the miniature cathodeless X-ray tube (3); The high-voltage transformer (1), the high-voltage multiplier rectifier (2) and the miniature cathodeless X-ray tube (3) are all arranged in a structural shielding box (5) and are filled with a high-voltage insulating potting glue (4) to form a sealed structure; The high-voltage multiplier rectifier (2) adopts a Cockcroft-Walton circuit form and has a ladder-shaped structure, which specifically includes: a first cylindrical capacitor component, a second cylindrical capacitor component, a plurality of first cylindrical diodes (8) and a plurality of second cylindrical diodes (9); The first columnar capacitor component and the second columnar capacitor component serve as the waist of the ladder structure, and the plurality of first cylindrical diodes (8) and the plurality of second cylindrical diodes (9) serve as the crossbeams of the ladder structure; The first cylindrical capacitor assembly and the second cylindrical capacitor assembly are both composed of a plurality of cylindrical capacitors (6) stacked and welded together in series; there are cylindrical capacitor welds (7) with equal spacing between the cylindrical capacitors (6); the two pin-shaped pins of each first cylindrical diode (8) and each second cylindrical diode (9) are respectively welded at the corresponding cylindrical capacitor welds (7) on the two waists; the first cylindrical diode (8) and the second cylindrical diode (9) are respectively evenly distributed along the front and back sides of the waist of the ladder structure and welded in parallel; the first cylindrical diode is located on the front side of the waist of the ladder structure, and the second cylindrical diode is located on the back side of the waist of the ladder structure; and each first cylindrical diode (8) and each second cylindrical diode (9) are relatively cross-arranged; The miniature cathodeless X-ray tube (3) comprises a high-voltage electrode (10), a ground electrode (12) and a ray target (13). When the high-voltage electrode (10) is connected to a negative DC high voltage, residual gas in the tube is discharged, and eventually electrons hit the ray target (13) to generate X-rays.

2. The miniature cathodeless X-ray generator for space X-ray detector calibration according to claim 1, characterized in that: The high-voltage transformer (1) and the high-voltage multiplier rectifier (2) together form a high-voltage power supply, which is connected to the high-voltage pole (10) of the miniature cathodeless X-ray tube (3).

3. The miniature cathodeless X-ray generator for space X-ray detector calibration according to claim 1, characterized in that: The miniature cathodeless X-ray tube (3) is a cathodeless X-ray closed tube suitable for space use, and further comprises: sealing ceramics (11); The sealing ceramic (11) is a hollow cylindrical structure, and the high-voltage electrode (10) and the grounding electrode (12) are respectively placed at both ends of the sealing ceramic (11); the high-voltage electrode (10) is a disc structure, and the grounding electrode is a ring structure and is connected to the ground of the high-voltage power supply; the ray target (13) is placed in the center of the ring of the grounding electrode (12), and the side of the ray target (13) coated with a metal film is placed inside the X-ray tube, opposite to the high-voltage electrode (10); The high voltage electrode (10), the sealing ceramic (11), the ground electrode (12) and the ray target (13) are brazed together by vacuum, and the atmospheric pressure inside the electrode is between 10<-1 > and 10<-3 >Pa.

4. The miniature cathodeless X-ray generator for space X-ray detector calibration according to claim 3, characterized in that: The high voltage pole (10) is made of Kovar steel and is in the shape of a disc structure with uniform thickness, and the thickness is 0.5-2 mm.

5. The miniature cathodeless X-ray generator for space X-ray detector calibration according to claim 3, characterized in that: The sealing ceramic (11) is aluminum oxide ceramic and is used to isolate the high voltage electrode (10) and the grounding electrode (12). The height of the sealing ceramic (11) is between 5 and 20 mm.

6. The miniature cathodeless X-ray generator for space X-ray detector calibration according to claim 3, characterized in that: The grounding electrode (12) is made of an annular Kovar steel material with uniform thickness, and its thickness is within the range of 0.5-2 mm.

7. The miniature cathodeless X-ray generator for space X-ray detector calibration according to claim 3, characterized in that: The base material of the ray target (13) is a beryllium sheet, and tungsten is plated on either side of the beryllium sheet for generating X-rays. The thickness of the coating is greater than 0.1 micrometers; the thickness of the beryllium sheet is greater than 0.2 mm.

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