CN107402401B - Multichannel hard X-ray imaging detector with time gating - Google Patents
Multichannel hard X-ray imaging detector with time gating Download PDFInfo
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- 238000003384 imaging method Methods 0.000 title claims abstract description 17
- 238000001514 detection method Methods 0.000 claims abstract description 90
- 239000000758 substrate Substances 0.000 claims description 34
- 239000000843 powder Substances 0.000 claims description 14
- 229910052783 alkali metal Inorganic materials 0.000 claims description 12
- 150000001340 alkali metals Chemical class 0.000 claims description 11
- 239000011248 coating agent Substances 0.000 claims description 9
- 238000000576 coating method Methods 0.000 claims description 9
- 238000007747 plating Methods 0.000 claims description 9
- 229910052751 metal Inorganic materials 0.000 claims description 7
- 239000002184 metal Substances 0.000 claims description 7
- 230000000149 penetrating effect Effects 0.000 claims description 6
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 claims description 3
- 229910052790 beryllium Inorganic materials 0.000 claims description 3
- ATBAMAFKBVZNFJ-UHFFFAOYSA-N beryllium atom Chemical compound [Be] ATBAMAFKBVZNFJ-UHFFFAOYSA-N 0.000 claims description 3
- 230000000630 rising effect Effects 0.000 claims description 3
- 239000010936 titanium Substances 0.000 claims description 3
- 229910052719 titanium Inorganic materials 0.000 claims description 3
- 239000011148 porous material Substances 0.000 claims description 2
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 11
- 239000000126 substance Substances 0.000 description 6
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- 238000010586 diagram Methods 0.000 description 3
- 230000005284 excitation Effects 0.000 description 3
- 238000002474 experimental method Methods 0.000 description 3
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- 230000009286 beneficial effect Effects 0.000 description 1
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- G01T—MEASUREMENT OF NUCLEAR OR X-RADIATION
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Abstract
The invention discloses a hard X-ray imaging detector, which solves the problems that the time resolution and the space resolution are low and the field of view is small so as not to meet the actual detection requirement in the prior art when detecting hard X-rays. The invention comprises a sealed vacuum cavity formed by the joint enclosing of a detector frame body, a ray filter window and a fluorescent screen, a multichannel hard X-ray detection photocathode and a microchannel plate which are all arranged in the vacuum cavity, and a pulse high-voltage power supply; the pulsed high voltage power supply provides working voltages for the multichannel hard X-ray detection photocathode and the microchannel plate respectively, and loads voltages between the multichannel hard X-ray detection photocathode and the microchannel plate and between the microchannel plate and the fluorescent screen. The invention has simple structure, scientific and reasonable design and convenient use, can effectively improve the time resolution, optimize the spatial resolution and the object space resolution when detecting the hard X-rays, has the time gating function and has a large detection view field.
Description
Technical Field
The invention relates to the field of plasma physics and nuclear detection, in particular to a multichannel hard X-ray imaging detector with time gating.
Background
The hard X-rays interact with matter mainly by the photoelectric effect and compton effect, and each effect produces a corresponding high energy primary electron. These primary electrons continue to interact with the species, causing ionization and excitation of atoms, molecules of the species. If the ionization and excitation signals generated in a substance can be extracted from the substance and collected and amplified to become the electric pulse signals for analysis and recording, the substance can be used as the detection medium of a hard X-ray detector.
The hard X-rays may have a photoelectric effect and a compton effect in any substance, but not any substance may be used as a detection medium for the hard X-rays. Ionization and excitation of secondary electrons in a substance is the generation of electron ion pairs, flashes, electron hole pairs, and the like. It is apparent that these signals cannot be extracted in opaque insulating materials and thicker conductors. Whereas very thin metal film detection cathodes can only detect soft X-rays, current hard X-ray imaging detectors are typically scintillator detectors. Because scintillators have long afterglow times (several ns to hundreds of ns), they are far from meeting the time resolution requirements and gating time requirements in certain scientific experiments. Therefore, designing a multi-channel hard X-ray imaging detector with time gating to improve the time resolution, optimize the spatial resolution and the object space resolution when detecting the hard X-rays with the energy range of 10keV-300keV becomes a technical problem to be solved by those skilled in the art.
Disclosure of Invention
The invention aims to solve the technical problems that: the multichannel hard X-ray imaging detector with time gating is provided, and the problems that in the prior art, when hard X-rays with the energy range of 10keV-300keV are detected, the time resolution and the spatial resolution are low, and the detection field of view is small, so that the actual detection requirement cannot be met are solved.
In order to achieve the above purpose, the technical scheme adopted by the invention is as follows:
a multichannel hard X-ray imaging detector with time gating comprises a sealed vacuum cavity, a multichannel hard X-ray detection photocathode, a microchannel plate and a pulse high-voltage power supply, wherein the vacuum cavity is mainly formed by the joint surrounding of a detector frame body, a ray filter window and a fluorescent screen;
the ray filter window, the multichannel hard X-ray detection photocathode, the microchannel plate and the fluorescent screen are sequentially arranged in parallel, and the ray filter window and the fluorescent screen are respectively positioned at the front end and the rear end of the vacuum cavity; the multi-channel hard X-ray detection photocathode is used for detecting the hard X-rays entering the vacuum cavity through the ray filter window and converting detected hard X-ray signals into electronic signals to be output, the micro-channel plate is used for gaining electrons from the multi-channel hard X-ray detection photocathode, and the fluorescent screen is used for converting the electronic signals after gain of the micro-channel plate into visible light signals;
the pulse high-voltage power supply is positioned outside the vacuum cavity and is respectively and electrically connected with the multichannel hard X-ray detection photocathode, the microchannel plate and the fluorescent screen and is used for providing working voltages for the multichannel hard X-ray detection photocathode and the microchannel plate, and meanwhile, the pulse high-voltage power supply also loads voltages between the multichannel hard X-ray detection photocathode and the microchannel plate and between the microchannel plate and the fluorescent screen, and the loaded voltages play roles of guiding electron propagation and increasing electron energy so as to enhance visible light signals.
Further, the vacuum degree of the vacuum cavity is higher than 1×10 -2 Pa, the ray filter window is a titanium window or a beryllium window, and the thickness is 0.1mm-1mm.
Further, the multi-channel hard X-ray detection photocathode comprises a cathode substrate which reacts with the irradiated hard X-ray photons under the irradiation of the hard X-ray photons to generate primary photoelectrons, and more than two cathode channels which are equidistantly arranged on the cathode substrate, wherein each cathode channel inner wall is provided with an alkali metal plating layer, all the cathode channels are penetrating pore channels penetrating through the front side and the back side of the cathode substrate, when the primary photoelectrons generated on the cathode substrate reach the cathode channels, the alkali metal plating layers on the inner wall of the cathode channels are ionized to generate low-energy secondary electrons, and the secondary electrons are amplified in the cathode channels through avalanche and then are discharged to the microchannel plate under the action of voltage between the multi-channel hard X-ray detection photocathode and the microchannel plate; all the cathode channels have the same diameter of 3 μm to 30 μm, all the adjacent cathode channels have the same spacing of 5 μm to 35 μm, and all the cathode channels have the same included angle with the normal of the cathode substrate of 0.1 ° to 15 °.
Further, the cathode substrate comprises Pb, si and O elements, wherein the mass percentage of the lead element is not less than 40%.
Further, the working gain of the multichannel hard X-ray detection photocathode is 5-100, the thickness of the cathode substrate is 0.5-3mm, the secondary electrons are electrons with energy smaller than 50eV, and the alkali metal coating is preferably a metal Na coating or a metal K coating.
Further, the distance between the multichannel hard X-ray detection photocathode and the ray filter window is 1mm-30mm, the distance between the micro-channel plate and the multichannel hard X-ray detection photocathode is 0.3mm-2mm, and the distance between the fluorescent screen and the micro-channel plate is 0.8mm-3mm.
Further, the thickness of the microchannel plate is 0.4mm-2mm, and the gain of electrons is 200-10000; the fluorescent powder layer on the fluorescent screen is positioned in the vacuum cavity, the thickness of the fluorescent powder layer is 3-8 mu m, and the fluorescent powder adopted by the fluorescent powder layer is P11 type fluorescent powder or P46 type fluorescent powder.
Further, the voltage between the front and rear end faces of the multichannel hard X-ray detection photocathode is 200V-2000V, the voltage between the front and rear end faces of the microchannel plate is 500V-2000V, the voltage between the multichannel hard X-ray detection photocathode and the microchannel plate is 50V-500V, and the voltage between the microchannel plate and the fluorescent screen is 3000V-8000V.
Further, the voltage between the front end face and the rear end face of the microchannel plate is pulse voltage, the pulse width is 3ns-20ns, and the rising time and the falling time of the pulse voltage are both smaller than 1.5ns; the voltage between the microchannel plate and the phosphor screen is a pulsed voltage and its pulse width is 5 μs-20 μs.
Further, the hard X-rays are hard X-rays with energy ranges of 10keV-300 keV.
Compared with the prior art, the invention has the following beneficial effects:
(1) The invention has simple structure, scientific and reasonable design and convenient use, can effectively improve the time resolution and optimize the spatial resolution when detecting the hard X-rays with the energy range of 10keV-300keV, has the time gating function and has a large detection view field.
(2) The invention arranges the ray filter, the multichannel hard X-ray detection photocathode, the micro-channel plate and the fluorescent screen in parallel in sequence, the ray filter and the fluorescent screen are arranged at the front end and the rear end of the vacuum cavity, the multichannel hard X-ray detection photocathode adopts a plurality of cathode channels which are distributed in an equidistant array on a cathode substrate, an alkali metal plating layer is plated on the inner wall of the cathode channel, the thickness of the multichannel hard X-ray detection photocathode (namely the cathode substrate) is set to be 0.5mm-3mm, an included angle of 0.1-15 DEG is arranged between all the cathode channels and the normal line of the cathode substrate, and the thickness of a fluorescent powder layer on the fluorescent screen is 3 mu m-8 mu m; meanwhile, the distance between the multichannel hard X-ray detection photocathode and the ray filter window is set to be 1mm-30mm, the distance between the micro-channel plate and the multichannel hard X-ray detection photocathode is set to be 0.3mm-2mm, and the distance between the fluorescent screen and the micro-channel plate is set to be 0.8mm-3mm; and a voltage of 200V-2000V is loaded between the front end face and the rear end face of the multichannel hard X-ray detection photocathode, a voltage of 500V-2000V is loaded between the front end face and the rear end face of the microchannel plate, a voltage of 50V-500V is loaded between the multichannel hard X-ray detection photocathode and the microchannel plate, and a voltage of 3000V-8000V is loaded between the microchannel plate and the fluorescent screen; through the special compact design, when the invention detects the hard X-rays with the energy range of 10keV-300keV, the time resolution can be effectively improved by at least one order of magnitude, the spatial resolution is optimized to 0.6mm, the spatial resolution of an object space can reach 10 mu m through proper experimental layout, and meanwhile, the invention also has a time gating function and a large detection view field.
(3) When the detected rays irradiate the ray filter window, the ray filter window shields soft X rays and beta rays in the detected rays, the hard X rays with the energy band range of 10keV-300keV in the detected rays can pass through the ray filter window to enter the vacuum cavity and irradiate the multichannel hard X-ray detection photocathode, the hard X-ray signals entering the vacuum cavity are converted into electronic signals after passing through the multichannel hard X-ray detection photocathode, the gain of the converted electronic signals is obtained in the cathode channel of the multichannel hard X-ray detection photocathode, the electronic signals converted and gained by the multichannel hard X-ray detection photocathode come to the microchannel plate under the voltage action between the multichannel hard X-ray detection photocathode and the microchannel plate, and the signals are enhanced by the microchannel plate, the enhanced electronic signal comes to the fluorescent screen under the action of the voltage between the micro-channel plate and the fluorescent screen, and the unique multi-channel hard X-ray detection photocathode converts the hard X-ray signal with the energy range of 10keV-300keV into the electronic signal and gains the electronic signal, meanwhile, the micro-channel plate gains the electronic signal greatly again, under the action of the high voltage between the micro-channel plate and the fluorescent screen, the electronic signal is enhanced again, and the electronic signal with the great gain is converted into a visible light signal which is convenient for recording and detection by the fluorescent screen, so the detector has better detection efficiency, can be used for weak light detection, and can meet the time resolution requirement and the gating time technical requirement in scientific experiments.
Drawings
FIG. 1 is a schematic diagram of the structure of the present invention.
FIG. 2 is a schematic diagram of a multi-channel hard X-ray detection photocathode structure according to the present invention.
Fig. 3 is a sectional view A-A in fig. 2.
FIG. 4 is a block diagram of the external circuit of the pulse high voltage power supply of the present invention.
Wherein, the names corresponding to the reference numerals are:
1-detector frame, 2-ray filter, 3-multichannel hard X-ray detection photocathode, 4-microchannel plate, 5-fluorescent screen, 6-pulse high voltage power supply, 7-vacuum cavity, 31-cathode substrate, 32-cathode channel, 33-alkali metal coating.
Detailed Description
The invention will be further illustrated by the following description and examples, which include but are not limited to the following examples.
As shown in figures 1-4, the multichannel hard X-ray imaging detector with time gating provided by the invention has the advantages of simple structure, scientific and reasonable design and convenience in use, can effectively improve the time resolution and optimize the spatial resolution when detecting the hard X-rays with the energy range of 10keV-300keV, has the time gating function, and simultaneously has a large detection view field. The invention comprises a sealed vacuum cavity 7 mainly formed by the joint enclosing of a detector frame body 1, a ray filter 2 and a fluorescent screen 5, a multichannel hard X-ray detection photocathode 3 and a microchannel plate 4 which are both arranged in the vacuum cavity 7, and a pulse high-voltage power supply 6, wherein the vacuum cavity 7 is in a vacuum environment; the vacuum degree of the vacuum cavity 7 is higher than 1 multiplied by 10 -2 Pa, the ray filter window 2 is a titanium window or a beryllium window, and the thickness is 0.1mm-1mm,the hard X-rays are hard X-rays with energy ranges of 10keV-300 keV.
According to the invention, the ray filter 2, the multichannel hard X-ray detection photocathode 3, the microchannel plate 4 and the fluorescent screen 5 are sequentially arranged in parallel, and the ray filter 2 and the fluorescent screen 5 are respectively positioned at the front end and the rear end of the vacuum cavity 7; the radiation filter 2 is used for allowing hard X-rays to pass through and shoot into the vacuum cavity 7 when receiving radiation irradiation, and shielding soft X-rays and beta-rays, the multichannel hard X-ray detection photocathode 3 is used for detecting hard X-rays entering the vacuum cavity 7 through the radiation filter 2, and converting detected hard X-ray signals into electronic signals for output, the microchannel plate 4 is used for gaining electrons from the multichannel hard X-ray detection photocathode 3, and the fluorescent screen 5 is used for converting the electronic signals obtained after gain of the microchannel plate 4 into visible light signals.
The pulse high-voltage power supply 6 is positioned outside the vacuum cavity 7 and is respectively and electrically connected with the multichannel hard X-ray detection photocathode 3, the microchannel plate 4 and the fluorescent screen 5 and is used for providing working voltages for the multichannel hard X-ray detection photocathode 3 and the microchannel plate 4, and meanwhile, the pulse high-voltage power supply 6 also loads voltages between the multichannel hard X-ray detection photocathode 3 and the microchannel plate 4 and between the microchannel plate 4 and the fluorescent screen 5.
When the detected rays irradiate the ray filter window, the ray filter window shields soft X rays and beta rays in the detected rays, the hard X rays with the energy band range of 10keV-300keV in the detected rays can pass through the ray filter window to enter the vacuum cavity and irradiate the multichannel hard X-ray detection photocathode, the hard X-ray signals entering the vacuum cavity are converted into electronic signals after passing through the multichannel hard X-ray detection photocathode, the gain of the converted electronic signals is obtained in the cathode channel of the multichannel hard X-ray detection photocathode, the electronic signals converted and gained by the multichannel hard X-ray detection photocathode come to the microchannel plate under the voltage action between the multichannel hard X-ray detection photocathode and the microchannel plate, and the signals are enhanced by the microchannel plate, the enhanced electronic signal comes to the fluorescent screen under the action of the voltage between the micro-channel plate and the fluorescent screen, and the unique multi-channel hard X-ray detection photocathode converts the hard X-ray signal with the energy range of 10keV-300keV into the electronic signal and gains the electronic signal, meanwhile, the micro-channel plate gains the electronic signal greatly again, under the action of the high voltage between the micro-channel plate and the fluorescent screen, the electronic signal is enhanced again, and the electronic signal with the great gain is converted into a visible light signal which is convenient for recording and detection by the fluorescent screen, so the detector has better detection efficiency, can be used for weak light detection, and can meet the time resolution requirement and the gating time technical requirement in scientific experiments.
The multichannel hard X-ray detection photocathode 3 comprises a cathode substrate 31 which reacts with the irradiated hard X-ray photons under the irradiation of the hard X-ray photons to generate primary photoelectrons, and more than two cathode channels 32 which are equidistantly arranged on the cathode substrate 31, wherein the components of the cathode substrate 31 are Pb, si and O elements, and the mass percentage of the Pb elements is not less than 40 percent. An alkali metal coating 33 is arranged on the inner wall of each cathode channel 32, all the cathode channels 32 are penetrating channels penetrating through the front surface and the back surface of the cathode substrate 31, when primary photoelectrons generated on the cathode substrate 31 reach the cathode channels 32, the alkali metal coating 33 on the inner wall of the cathode channels 32 are ionized to generate low-energy secondary electrons, and the secondary electrons are amplified in the cathode channels 32 through avalanche and then are applied to the microchannel plates 4 under the action of voltage between the multichannel hard X-ray detection photocathodes 3 and the microchannel plates 4; all the cathode channels 32 have the same diameter of 3 μm to 30 μm, all the adjacent cathode channels 32 have the same pitch of 5 μm to 35 μm, and all the cathode channels 32 are aligned with the normal line of the cathode substrate 31 at an angle of 0.1 ° to 15 °.
The working gain of the multichannel hard X-ray detection photocathode 3 is 5-100, the thickness of the cathode substrate 31 is 0.5-3mm, the secondary electrons are electrons with energy smaller than 50eV, and the alkali metal plating layer 33 is preferably a metal Na plating layer or a metal K plating layer.
The thickness of the multichannel hard X-ray detection photocathode (namely the cathode substrate) is 0.5-3mm, the shape can be formulated according to practical conditions, the diameter of the cathode channel is 3-30 mu m, the distance between adjacent cathode channels is 5-35 mu m, and an included angle of 0.1-15 DEG is formed between the cathode channel and the normal line of the cathode substrate; the spacing between adjacent cathode channels forms a wall thickness between the adjacent cathode channels, and the cathode substrate can be thick to detect hard X-rays with the energy range of 10-300keV because the cathode substrate is provided with a plurality of cathode channels in an array at equal intervals, so that the high-energy primary photoelectrons can reach the inside of the cathode channels only by passing through the wall thickness between the cathode channels; meanwhile, when the invention detects the hard X-ray with the energy range of 10-300keV, the generated primary photoelectrons and secondary electrons are ionized, and the ionization process can be regarded as a transient physical process, and the time scale is about 1 multiplied by 10 -21 s is far smaller than the flyback relaxation time of the scintillator, so that the aim of short afterglow time is effectively fulfilled; the time resolution can thus be increased by at least one order of magnitude compared to the prior art, while the spatial resolution can also be optimized to 0.06mm.
The distance between the multichannel hard X-ray detection photocathode 3 and the ray filter window 2 is 1mm-30mm, the distance between the micro-channel plate 4 and the multichannel hard X-ray detection photocathode 3 is 0.3mm-2mm, and the distance between the fluorescent screen 5 and the micro-channel plate 4 is 0.8mm-3mm.
The thickness of the microchannel plate 4 is 0.4mm-2mm, and the gain of electrons is 200-10000; the phosphor layer on the fluorescent screen 5 is located in the vacuum cavity 7, the thickness of the phosphor layer is 3 μm-8 μm, and the phosphor used in the phosphor layer can be selected to be a proper type of phosphor according to the requirement, and the preferred type of phosphor in this embodiment is P11 type (ZnS: ag) phosphor or P46 type (YAG: ce) phosphor.
The voltage between the front and rear end faces of the multi-channel hard X-ray detection photocathode 3 of the present invention is 200V-2000V, that is, the voltage between the front and rear end faces of the cathode substrate 31 is 200V-2000V, the voltage between the front and rear end faces of the micro-channel plate 4 is 500V-2000V, the voltage between the multi-channel hard X-ray detection photocathode 3 (that is, the cathode substrate 31) and the micro-channel plate 4 is 50V-500V, and the voltage between the micro-channel plate 4 and the phosphor screen 5 is 3000V-8000V.
The voltage between the front end face and the rear end face of the microchannel plate 4 is pulse voltage, the pulse width is 3ns-20ns, and the rising time and the falling time of the pulse voltage are both less than 1.5ns; the voltage between the microchannel plate 4 and the phosphor screen 5 is a pulse voltage, and the pulse width thereof is 5 μs to 20 μs.
The invention arranges the ray filter, the multichannel hard X-ray detection photocathode, the micro-channel plate and the fluorescent screen in parallel in sequence, the ray filter and the fluorescent screen are arranged at the front end and the rear end of the vacuum cavity, the multichannel hard X-ray detection photocathode adopts a plurality of cathode channels which are distributed in an equidistant array on a cathode substrate, an alkali metal plating layer is plated on the inner wall of the cathode channel, the thickness of the cathode substrate is set to be 1mm-3mm, an included angle of 0.1-15 DEG is arranged between all the cathode channels and the normal line of the cathode substrate, and the thickness of a fluorescent powder layer on the fluorescent screen is 3 mu m-8 mu m; meanwhile, the distance between the multichannel hard X-ray detection photocathode and the ray filter window is set to be 1mm-30mm, the distance between the micro-channel plate and the multichannel hard X-ray detection photocathode is set to be 0.3mm-2mm, and the distance between the fluorescent screen and the micro-channel plate is set to be 0.8mm-3mm; and a voltage of 200V-2000V is loaded between the front end face and the rear end face of the multichannel hard X-ray detection photocathode, a voltage of 500V-2000V is loaded between the front end face and the rear end face of the microchannel plate, a voltage of 50V-500V is loaded between the multichannel hard X-ray detection photocathode and the microchannel plate, and a voltage of 3000V-8000V is loaded between the microchannel plate and the fluorescent screen; through the special compact design, when the invention detects the hard X-rays with the energy range of 10keV-300keV, the time resolution can be effectively improved by at least one order of magnitude, the spatial resolution is optimized to 0.6mm, the spatial resolution of an object reaches 10 mu m, and meanwhile, the invention has a time gating function and a strong view field effect.
The above embodiment is only one of the preferred embodiments of the present invention, and should not be used to limit the scope of the present invention, but all the insubstantial modifications or color changes made in the main design concept and spirit of the present invention are still consistent with the present invention, and all the technical problems to be solved are included in the scope of the present invention.
Claims (8)
1. A multi-channel hard X-ray imaging detector with time gating, characterized by: the detector comprises a vacuum cavity (7) which is sealed by being enclosed by a detector frame body (1), a ray filter window (2) and a fluorescent screen (5), a multichannel hard X-ray detection photocathode (3) and a microchannel plate (4) which are arranged in the vacuum cavity (7), and a pulse high-voltage power supply (6);
the ray filter (2), the multichannel hard X-ray detection photocathode (3), the microchannel plate (4) and the fluorescent screen (5) are sequentially arranged in parallel, and the ray filter (2) and the fluorescent screen (5) are respectively positioned at the front end and the rear end of the vacuum cavity (7); the multi-channel hard X-ray detection photocathode (3) is used for detecting the hard X-rays entering the vacuum cavity (7) through the ray filter (2) and converting detected hard X-ray signals into electronic signals to be output, the micro-channel plate (4) is used for gaining electrons from the multi-channel hard X-ray detection photocathode (3), and the fluorescent screen (5) is used for converting the electronic signals gained by the micro-channel plate (4) into visible light signals;
the pulse high-voltage power supply (6) is positioned outside the vacuum cavity (7) and is respectively electrically connected with the multichannel hard X-ray detection photocathode (3), the microchannel plate (4) and the fluorescent screen (5) and is used for providing working voltages for the multichannel hard X-ray detection photocathode (3) and the microchannel plate (4), and meanwhile, the pulse high-voltage power supply (6) also loads voltages between the multichannel hard X-ray detection photocathode (3) and the microchannel plate (4) and between the microchannel plate (4) and the fluorescent screen (5), and the loaded voltages play roles of guiding electron propagation and increasing electron energy so as to enhance visible light signals;
the multi-channel hard X-ray detection photocathode (3) comprises a cathode substrate (31) which reacts with the irradiated hard X-ray photons under the irradiation of the hard X-ray photons to generate primary photoelectrons, and more than two cathode channels (32) which are equidistantly arranged on the cathode substrate (31), wherein each cathode channel (32) is provided with an alkali metal plating layer (33) on the inner wall, all the cathode channels (32) are penetrating pore channels penetrating through the front surface and the back surface of the cathode substrate (31), when the primary photoelectrons generated on the cathode substrate (31) reach the cathode channels (32), the alkali metal plating layers (33) on the inner wall of the cathode channels (32) ionize to generate low-energy secondary electrons, and the secondary electrons are subjected to the voltage action between the multi-channel hard X-ray detection photocathode (3) and the micro-channel plate (4) after the secondary electrons are amplified in the cathode channels (32); all the cathode channels (32) have the same diameter of 3-30 μm, all the adjacent cathode channels (32) have the same spacing of 5-35 μm, and all the cathode channels (32) have an included angle consistent with the normal of the cathode substrate (31) of 0.1-15 °;
the cathode substrate (31) comprises Pb, si and O elements, wherein the mass percentage of the lead element is not less than 40%.
2. A multi-channel hard X-ray imaging detector with time gating according to claim 1, wherein: the vacuum degree of the vacuum cavity (7) is higher than 1 multiplied by 10 -2 Pa, the ray filter window (2) is a titanium window or a beryllium window, and the thickness is 0.1mm-1mm.
3. A multi-channel hard X-ray imaging detector with time gating according to claim 2, wherein: the working gain of the multichannel hard X-ray detection photocathode (3) is 5-100, the thickness of the cathode substrate (31) is 0.5-3mm, the secondary electrons are electrons with energy smaller than 50eV, and the alkali metal coating (33) is a metal Na coating or a metal K coating.
4. A multi-channel hard X-ray imaging detector with time gating according to claim 3, wherein: the distance between the multichannel hard X-ray detection photocathode (3) and the ray filter window (2) is 1mm-30mm, the distance between the microchannel plate (4) and the multichannel hard X-ray detection photocathode (3) is 0.3mm-2mm, and the distance between the fluorescent screen (5) and the microchannel plate (4) is 0.8mm-3mm.
5. A multi-channel hard X-ray imaging detector with time gating according to claim 4, wherein: the thickness of the microchannel plate (4) is 0.4mm-2mm, and the gain of electrons is 200-10000; the fluorescent powder layer on the fluorescent screen (5) is positioned in the vacuum cavity (7), the thickness of the fluorescent powder layer is 3-8 mu m, and the fluorescent powder adopted by the fluorescent powder layer is P11 type fluorescent powder or P46 type fluorescent powder.
6. A multi-channel hard X-ray imaging detector with time gating according to claim 5, wherein: the voltage between the front end face and the rear end face of the multichannel hard X-ray detection photocathode (3) is 200V-2000V, the voltage between the front end face and the rear end face of the microchannel plate (4) is 500V-2000V, the voltage between the multichannel hard X-ray detection photocathode (3) and the microchannel plate (4) is 50V-500V, and the voltage between the microchannel plate (4) and the fluorescent screen (5) is 3000V-8000V.
7. A multi-channel hard X-ray imaging detector with time gating according to claim 6, wherein: the voltage between the front end face and the rear end face of the microchannel plate (4) is pulse voltage, the pulse width is 3ns-20ns, and the rising time and the falling time of the pulse voltage are both less than 1.5ns; the voltage between the microchannel plate (4) and the fluorescent screen (5) is a pulse voltage, and the pulse width thereof is 5-20 mu s.
8. A multi-channel hard X-ray imaging detector with time gating according to any one of claims 1-7, wherein: the hard X-rays are hard X-rays with energy ranges of 10keV-300 keV.
Priority Applications (1)
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| CN107765506B (en) * | 2017-11-29 | 2023-11-14 | 中国工程物理研究院激光聚变研究中心 | Hard X-ray framing camera and method for detecting hard X-rays by using same |
| CN107807377A (en) * | 2017-11-29 | 2018-03-16 | 中国工程物理研究院激光聚变研究中心 | Multichannel hard X ray position sensitive detector and its detection hard X ray method |
| CN108020325B (en) * | 2017-12-13 | 2023-06-30 | 深圳大学 | Flight time measurement system based on microchannel plate gating technology |
| CN109991652B (en) * | 2019-04-12 | 2022-08-02 | 中国科学院合肥物质科学研究院 | Built-in remote control photoelectric detection system |
| CN111190216B (en) * | 2020-01-23 | 2023-03-24 | 中国工程物理研究院激光聚变研究中心 | Radiation flow detector array |
| CN112116795B (en) * | 2020-08-04 | 2021-12-17 | 中国原子能科学研究院 | Method and device for testing instantaneous response of nuclear critical accident alarm |
| CN114088755B (en) * | 2021-11-03 | 2023-09-01 | 西北核技术研究所 | Time resolution X-ray diffraction measurement device and method |
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