Photon counting imaging detector with multiband composite detection capability

Abstract

The invention relates to a photon counting imaging detector, in particular to a photon counting imaging detector with multiband composite detection capability, and solves the technical problem that an existing position-sensitive anode detector cannot detect multiple bands at the same time. The photon counting imaging detector with the multiband composite detection capability comprises a vacuum packaging tube body array, and a position-sensitive anode assembly, a detector frame and a detector end cover which are sequentially connected from bottom to top, the receiving ends of the vacuum packaging tube bodies are upwards arranged in the mounting block, and the N * M receiving ends of the vacuum packaging tube bodies are respectively provided with the same or different photoelectric cathodes for receiving target optical signals of different wavebands and converting the target optical signals into photoelectrons; the output ends of the N * M vacuum packaging tube bodies are respectively provided with a high-resistance collecting layer for receiving the photoelectrons and converting the photoelectrons into electronic cloud cluster signals for outputting; and the position-sensitive anode assembly is used for sensing an electron cloud cluster signal and transmitting the electron cloud cluster signal to an external readout electronics system for processing.

Description

Technical Field

[0001] The present invention relates to a photon counting imaging detector, and more particularly to a photon counting imaging detector with multi-band composite detection capabilities. Background Art

[0002] Photon counting imaging detectors based on microchannel plates and position-sensitive anodes have the advantages of high signal-to-noise ratio, good anti-drift performance, and good time stability. At the same time, they have excellent time and space resolution capabilities and extremely high detection sensitivity, playing an important role in fields such as space astronomy, biomedicine, and quantum information. The main components of such detectors include an input window, a photoelectric conversion part (photoelectric cathode), an amplification and multiplication part (microchannel plate), and a position decoding part (position-sensitive anode and related external readout electronics system). Among them, the function of the photoelectric cathode in the detector is photoelectric conversion, which determines the detection band of the detector. Usually, photoelectric cathodes are distinguished according to different response ranges. For example, CsI cathodes are often used to detect the FUV band (100 - 200 nm), Cs2Te photocathodes are used to detect the NUV band (200 - 300 nm), and double-alkali or multi-alkali photocathodes (such as S20 and S25) can be used to detect the visible light band.

[0003] Space targets are relatively complex and usually contain multiple bands such as X-rays, ultraviolet rays, visible light, and infrared rays. Different detectors are required for different targets. A single position-sensitive anode photon counting imaging detector can only have one kind of photoelectric cathode. If the detection target needs to cover multiple bands and exceeds the detection band of a single position-sensitive anode photon counting imaging detector (such as detecting the FUV and visible light band ranges), multiple different position-sensitive anode photon counting imaging detectors need to be used. Therefore, each position-sensitive anode photon counting imaging detector must have a set of external readout electronics systems, which greatly increases the power consumption and complexity of the detection system. Summary of the Invention

[0004] The object of the present invention is to solve the technical problem that existing position-sensitive anode detectors cannot detect multiple bands simultaneously, and to provide a photon counting imaging detector with multi-band composite detection capabilities.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] A photon counting imaging detector with multi-band composite detection capabilities, characterized in that it includes an array of vacuum encapsulation tubes, and a position-sensitive anode assembly, a detector frame, and a detector end cover connected in sequence from bottom to top;

[0007] The detector frame is provided with N×M mounting partitions;

[0008] There are N×M mounting holes provided at positions corresponding to N×M mounting partitions on the detector end cap; N≥1, M≥1;

[0009] The vacuum encapsulation tube array includes N×M vacuum encapsulation tubes. The receiving ends of the vacuum encapsulation tubes are arranged upward inside the mounting partitions, and the receiving ends of the N×M vacuum encapsulation tubes are respectively provided with the same or different photocathodes for receiving target optical signals of different wavelength bands and converting them into photoelectrons; the output ends of the N×M vacuum encapsulation tubes are respectively provided with high-resistance collection layers for receiving photoelectrons and converting them into electron cloud signals for output;

[0010] The position-sensitive anode assembly is used to sense the electron cloud signal and transmit it to the external readout electronics system for processing.

[0011] Furthermore, the vacuum encapsulation tube includes a microchannel plate assembly and a housing; an input window is provided at the upper end of the housing, and a base is provided at the lower end. The base is attached to the upper surface of the position-sensitive anode assembly; the photocathode is provided on the lower surface of the input window; the microchannel plate assembly is arranged at the central position of the housing, and an electric field is formed between the microchannel plate assembly and the photocathode for multiplying and amplifying photoelectrons and then transmitting them to the high-resistance collection layer; the high-resistance collection layer is evaporated on the upper surface of the base, and the high-resistance collection layer and the position-sensitive anode assembly form a capacitive structure.

[0012] Furthermore, there is also a getter provided between the input window and the base for absorbing the gas released during the operation of the detector.

[0013] Furthermore, the position-sensitive anode assembly includes an anode substrate and a delay-line anode or a crossed-strip anode or a discrete multi-anode array provided on the anode substrate; the width of the lower-layer collection metal electrode of the delay-line anode and the crossed-strip anode is greater than that of the upper-layer collection metal electrode; both the lower-layer collection metal electrode and the upper-layer collection metal electrode are connected to the external readout electronics system through lead electrodes; each electrode of the discrete multi-anode array is square with a side length of 0.5 mm to 10 mm, and each electrode is connected with a lead electrode for connecting to the external readout electronics system.

[0014] Furthermore, the input windows of the N×M vacuum encapsulation tubes have the same thickness.

[0015] Furthermore, the microchannel plate assembly adopts 2 microchannel plates cascaded in a V shape or 3 microchannel plates cascaded in a Z shape to improve the gain performance.

[0016] Furthermore, the material of the high-resistance collection layer is Ge, and the base is made of alumina ceramic with a thickness of 0.5 to 4 mm;

[0017] Furthermore, the photocathode is a CsI cathode or a Cs2Te cathode or a multi-alkali cathode or a semiconductor cathode.

[0018] Further, lead-out holes are provided on the detector frame for passing high-voltage leads.

[0019] Further, both the detector frame and the detector end cap are made of insulating materials; N = 2, M = 2.

[0020] Advantages of the present invention:

[0021] 1. In the photon counting imaging detector with multi-band composite detection ability of the present invention, each vacuum encapsulation tube body can respectively adopt photocathodes for different detection bands. After being combined with the corresponding external readout electronics system, it can realize the detection and imaging of detection targets in multiple bands simultaneously.

[0022] 2. In the photon counting imaging detector with multi-band composite detection ability of the present invention, multiple vacuum encapsulation tube bodies share the same position-sensitive anode assembly. The position-sensitive anode assembly can simultaneously receive the electron cloud signals output by different vacuum encapsulation tube bodies. Therefore, the entire photon counting imaging detector only needs a set of external readout electronics systems, greatly reducing the power consumption and complexity of the external readout electronics system.

[0023] 3. In the photon counting imaging detector with multi-band composite detection ability of the present invention, each vacuum encapsulation tube body adopts the same photocathode, and a large-area mosaic detector array can be formed, expanding the effective area of the detector.

[0024] 4. The photon counting imaging detector with multi-band composite detection ability of the present invention can simultaneously perform high-time and high-space resolution multi-band composite detection, and has important application value in the fields of space astronomy, bioluminescence, etc. Description of the Drawings

[0025] Figure 1 is an exploded view of an embodiment of the photon counting imaging detector with multi-band composite detection ability of the present invention;

[0026] Figure 2 is an external view of the vacuum encapsulation tube body in an embodiment of the photon counting imaging detector with multi-band composite detection ability of the present invention;

[0027] Figure 3 is Figure 2 a cross-sectional view along A-A;

[0028] Figure 4 is a schematic structural view of the position-sensitive anode assembly formed by attaching the cross-bar anode to the anode substrate in an embodiment of the photon counting imaging detector with multi-band composite detection ability of the present invention;

[0029] Figure 5In an embodiment of a photon counting imaging detector with multi-band compound detection ability of the present invention, it is a schematic structural diagram of a position-sensitive anode assembly formed by attaching a delay line anode to an anode substrate;

[0030] Figure 6 In an embodiment of a photon counting imaging detector with multi-band compound detection ability of the present invention, it is a schematic structural diagram of a position-sensitive anode assembly formed by attaching a multi-anode array to an anode substrate.

[0031] Explanation of reference numerals:

[0032] 1 - Position-sensitive anode assembly, 2 - Vacuum encapsulation tube body, 21 - Input window, 22 - Photoelectric cathode, 23 - Microchannel plate assembly, 24 - Housing, 25 - High-resistance collection layer, 26 - Substrate, 27 - Getter, 3 - Detector frame, 4 - Detector end cap. Detailed implementation manners

[0033] As Figure 1 、 Figure 2 shown, a photon counting imaging detector with multi-band compound detection ability includes an array of vacuum encapsulation tube bodies, and a position-sensitive anode assembly 1, a detector frame 3, and a detector end cap 4 connected in sequence from bottom to top; N×M installation partitions are provided on the detector frame 3; N×M installation holes are provided at positions corresponding to the N×M installation partitions on the detector end cap 4; N≥1, M≥1.

[0034] The array of vacuum encapsulation tube bodies includes N×M vacuum encapsulation tube bodies 2. The receiving ends of the vacuum encapsulation tube bodies 2 are arranged upward inside the installation partitions, and the receiving ends of the N×M vacuum encapsulation tube bodies 2 are respectively provided with the same or different photoelectric cathodes 22 for receiving target optical signals of different bands and converting them into photoelectrons; the output ends of the N×M vacuum encapsulation tube bodies 2 are respectively provided with high-resistance collection layers 25 for receiving photoelectrons and converting them into electron cloud signals for output; the position-sensitive anode assembly 1 is used to sense the electron cloud signals and transmit them to an external readout electronics system for processing.

[0035] As Figure 3As shown in the figure, the vacuum encapsulation tube body 2 includes a getter 27, a microchannel plate assembly 23, and a housing 24; an input window 21 is provided at the upper end of the housing 24, and a base 26 is provided at the lower end. The base 26 is in contact with the upper surface of the position-sensitive anode assembly 1; a photocathode 22 is provided on the lower surface of the input window 21; the microchannel plate assembly 23 is provided at the central position of the housing 24, and an electric field is formed between the microchannel plate assembly 23 and the photocathode 22 for multiplying and amplifying photoelectrons and then transporting them to the high-resistance collection layer 25; the high-resistance collection layer 25 is evaporated on the upper surface of the base 26, and the high-resistance collection layer 25 and the position-sensitive anode assembly 1 form a capacitive structure. The high-resistance collection layer 25 reads out the electron cloud signal by means of mirror charge coupling. The getter 27 is provided between the input window 21 and the base 26 for absorbing the gas released during the operation of the detector.

[0036] The position-sensitive anode assembly 1 includes an anode substrate and a delay-line anode or a crossed-strip anode or a discrete multi-anode array provided on the anode substrate; the delay-line anode and the crossed-strip anode are perpendicularly crossed to form electrodes; the width of the lower-layer collection metal electrode on the receiving surface (upper surface) of the delay-line anode and the crossed-strip anode is greater than the width of the upper-layer collection metal electrode, so as to ensure that the number of electrons collected by the upper-layer collection metal electrode and the lower-layer collection metal electrode on the receiving surface of the delay-line anode and the crossed-strip anode is equivalent, so as to achieve the balance of the output induction signal. Both the lower-layer collection metal electrode and the upper-layer collection metal electrode are connected to an external readout electronics system through lead electrodes. The delay-line anode has 4 electrodes, all of which are connected with leads; the crossed-strip anode is adopted, which has the advantages of a compact form structure, good spatial resolution and time resolution. Each electrode of the discrete multi-anode array is square, with a side length of 0.5 mm to 10 mm, and each electrode is connected with a lead electrode for connecting to an external readout electronics system.

[0037] As Figure 4 shown in the figure, the crossed-strip anode is attached to the anode substrate, and its mutually insulated crossed electrode array is used to decode the centroid position of the induced electron cloud. Both the upper-layer collection electrode array and the lower-layer collection electrode array of the crossed electrode array are connected to an external readout electronics system through lead electrodes; the upper-layer collection electrode array and the lower-layer collection electrode array are isolated by an insulating material. The width of the lower-layer collection electrode is greater than the width of the upper-layer collection electrode, so that the amount of electric charge collected by the upper-layer collection electrode and the lower-layer collection electrode is equivalent, realizing the balance of the output signal.

[0038] As Figure 5As shown in the figure, the delay line anode is attached to the anode substrate to form upper and lower layers of vertically crossed serpentine metal electrodes. The upper and lower layers of vertically crossed serpentine metal electrodes are isolated by an insulating material. The width of the lower serpentine metal electrode is greater than that of the upper serpentine metal electrode, so that the amount of charge collected by the upper and lower serpentine metal electrodes is equivalent, and the balance of the output signal can be achieved. The outputs at both ends of the upper serpentine metal electrode and the lower serpentine metal electrode are connected to the external readout electronics system through lead electrodes.

[0039] As Figure 6 shown in the figure, the discrete multi-anode array is attached to the anode substrate to form a metal electrode array. Each metal electrode unit has a square structure, and the metal electrode units are isolated and insulated from each other. Each metal electrode unit needs to be connected to a lead electrode and is connected to the external readout electronics system through the lead electrode.

[0040] The photocathodes 22 of the N×M vacuum encapsulation tubes 2 are all the same or different, and can be selected according to the detection band to be detected. Specifically, a CsI cathode, a Cs2Te cathode, a multi-alkali cathode (such as S20 or S25), and a semiconductor cathode can be used. The microchannel plate assembly 23 uses 2 microchannel plates cascaded in a V shape or 3 microchannel plates cascaded in a Z shape. The single or multi-chip cascading of the microchannel plates can improve the gain performance. The detector frame 3 is provided with a lead-out hole for passing through the high-voltage lead. The material of the high-resistance collection layer 25 is Ge, and the substrate 26 uses 95% alumina (Al2O3) ceramic with a thickness of 0.5 - 4 mm; both the detector frame 3 and the detector end cap 4 use insulating materials, which fix the N×M vacuum encapsulation tubes 2 in the installation cavity.

[0041] In this embodiment, the position-sensitive anode assembly 1 is composed of a delay-line anode attached to an anode substrate to form two vertically intersecting serpentine metal electrodes in upper and lower layers. The wavelength bands to be detected are the far-ultraviolet band and the visible light band. The input windows 21 of the 2×2 vacuum encapsulation tubes 2 have the same thickness, and magnesium fluoride and quartz are respectively used for the input windows 21; photocathodes 22 are fabricated on the lower surfaces of the input windows 21 to form transmissive cathodes, so as to ensure that the photosensitive surfaces of the vacuum encapsulation tubes 2 are consistent, which is convenient for matching with an external electronic learning system; the photocathode 22 for detecting far-ultraviolet light can be selected as a CsI cathode, and the photocathode 22 for detecting visible light can be selected as an S20 cathode; the receiving area of the photocathode 22 is 30 mm×30 mm, and the 2×2 vacuum encapsulation tubes 2 share the same large-area position-sensitive anode assembly 1, and the electron cloud signals output by different vacuum encapsulation tubes 2 can be received by the same large-area position-sensitive anode assembly 1; the effective area of the large-area position-sensitive anode assembly 1 is 100 mm×100 mm; the effective area of a single vacuum encapsulation tube array is 30 mm×30 mm, and the distance between the cathode surface of the input window 21 and the upper surface of the microchannel plate assembly 23 is 0.2 mm. In the vacuum encapsulation tube 2, the microchannel plate assembly 23 is composed of two cascaded microchannel plates in a V-shaped structure. The high-resistance collection layer 25 is made of a semiconductor film layer (such as Ge), and the high-resistance collection layer 25 is fabricated on a ceramic substrate 26, and the thickness of the ceramic substrate 26 is 3 mm.

[0042] First, fix the large-area position-sensitive anode assembly 1 to the detector frame 3, reliably connect each high-voltage electrode in the vacuum encapsulation tube 2 to the high-voltage lead wire, then install the 2 vacuum encapsulation tubes 2 above the receiving surface of the position-sensitive anode assembly 1, and then make the substrate 26 of the vacuum encapsulation tube 2 closely adhere to the upper surface of the position-sensitive anode assembly 1; lead out the high-voltage lead wire from the side lead-out hole position of the detector frame 3, after inspection and confirmation, install the detector end cap 4 on the detector frame 3, and form an independent detection unit with the vacuum encapsulation tube 2 and the position-sensitive anode assembly 1, thus completing the assembly of the detector with multi-band composite detection capabilities.

Claims

1. A photon counting imaging detector with multi-band compound detection ability, characterized in that: It includes a vacuum encapsulated tube array, and a position-sensitive anode assembly (1), a detector frame (3), and a detector end cap (4) connected in sequence from bottom to top; There are N×M mounting partitions provided on the detector frame (3); There are N×M mounting holes provided at positions corresponding to the N×M mounting partitions on the detector end cap (4); N≥1, M≥1; The vacuum encapsulated tube array includes N×M vacuum encapsulated tubes (2). The receiving ends of the vacuum encapsulated tubes (2) are arranged upward inside the mounting partitions, and the receiving ends of the N×M vacuum encapsulated tubes (2) are respectively provided with the same or different photocathodes (22) for receiving target optical signals of different wavelength bands and converting them into photoelectrons; the output ends of the N×M vacuum encapsulated tubes (2) are respectively provided with high-resistance collection layers (25) for receiving photoelectrons and converting them into electron cloud signals for output; The position-sensitive anode assembly (1) is used to sense the electron cloud signal and convey it to an external readout electronics system for processing.

2. The photon counting imaging detector with multi-wavelength band composite detection ability according to claim 1, characterized in that: The vacuum encapsulated tube (2) includes a microchannel plate assembly (23) and a housing (24); The upper end of the housing (24) is provided with an input window (21), and the lower end is provided with a substrate (26). The substrate (26) is attached to the upper surface of the position-sensitive anode assembly (1); The photocathode (22) is arranged on the lower surface of the input window (21); The microchannel plate assembly (23) is arranged at the central position of the housing (24), and an electric field is formed between the microchannel plate assembly (23) and the photocathode (22) for multiplying and amplifying photoelectrons and then conveying them to the high-resistance collection layer (25); The high-resistance collection layer (25) is evaporated on the upper surface of the substrate (26), and the high-resistance collection layer (25) and the position-sensitive anode assembly (1) form a capacitive structure.

3. The photon counting imaging detector with multi-wavelength band composite detection ability according to claim 2, characterized in that: It further includes a getter (27) arranged between the input window (21) and the substrate (26) for absorbing the gas released during the operation of the detector.

4. The photon counting imaging detector with multi-wavelength band composite detection ability according to claim 3, characterized in that: The position-sensitive anode assembly (1) includes an anode substrate and a delay line anode or a cross-strip anode or a discrete multi-anode array arranged on the anode substrate; The width of the lower-layer collection metal electrode of the receiving surface of the delay line anode and the cross-strip anode is greater than the width of its upper-layer collection metal electrode; both the lower-layer collection metal electrode and the upper-layer collection metal electrode are connected to the external readout electronics system through lead electrodes; Each electrode of the discrete multi-anode array is square, with a side length of 0.5 mm to 10 mm, and each electrode is connected with a lead.

5. The photon counting imaging detector with multi-wavelength band composite detection ability according to claim 4, characterized in that: The thicknesses of the input windows (21) of the N×M vacuum encapsulated tubes (2) are the same.

6. The photon counting imaging detector with multi - band composite detection ability according to claim 5, characterized in that: The microchannel plate assembly (23) is composed of two microchannel plates cascaded in a V - shape or three microchannel plates cascaded in a Z - shape, which is used to improve the gain performance.

7. The photon counting imaging detector with multi - band composite detection ability according to claim 6, characterized in that: The material of the high - resistance collection layer (25) is Ge, and the substrate (26) is made of alumina ceramic with a thickness of 0.5 - 4 mm.

8. The photon counting imaging detector with multi - band composite detection ability according to claim 7, characterized in that: The photocathode (22) is a CsI cathode or a Cs2Te cathode or a multi - alkali cathode or a semiconductor cathode.

9. The photon counting imaging detector with multi - band composite detection ability according to claim 8, characterized in that: The detector frame (3) is provided with lead - out holes for passing through high - voltage leads.

10. The photon counting imaging detector with multi - band composite detection ability according to claim 9, characterized in that: Both the detector frame (3) and the detector end - cap (4) are made of insulating materials; where N = 2 and M = 2.

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