Hybrid photomultiplier coaxial output structure based on microstrip line

Abstract

The invention discloses a hybrid photomultiplier coaxial output structure based on a microstrip line. The hybrid photomultiplier coaxial output structure comprises a semiconductor detector, a bonding wire, the microstrip line, a ground electrode, a lead pin, a medium, an outer conductor base and a detector lead pin. The semiconductor detector is used for receiving the photoelectrons converted by the photoelectric cathode and generating a current signal; the bonding wire is used for electrically connecting the semiconductor detector and the microstrip structure; the microstrip line and the ground electrode adopt gold-plated kovar alloy parts to form an in-tube microstrip structure; the guide pin and the detector guide pin are kovar alloy guide pins and form an inner conductor with a coaxial structure; the outer conductor base is a kovar alloy disc and forms an outer conductor with a coaxial structure; the medium is glass or ceramic. According to the coaxial output structure, a vacuum tube is of a 50-ohm microstrip structure, the exterior of the vacuum tube is of a 50-ohm SMA coaxial structure, and a complete 50-ohm coaxial line is formed by connecting a microstrip line and a guide pin together. The structure provided by the invention has the advantages of high transmission speed, small signal reflection and oscillation and the like, and is more beneficial to detection of ultrafast optical pulse signals.

Description

Technical Field

[0001] This invention belongs to the field of vacuum photoelectric detection technology, and in particular to a coaxial output structure of a hybrid photomultiplier tube based on microstrip lines. Background Technology

[0002] Hybrid photomultiplier tubes combine the advantages of vacuum devices and solid-state devices while overcoming the shortcomings and deficiencies of both types of devices. They are widely used in fields such as high-energy pulsed radiation field measurement, time-correlated fluorescence afterglow testing, laser spectroscopy testing, quantum communication, astronomical observation, and laser ranging.

[0003] A hybrid photomultiplier tube (HMT) is an electrovacuum device that converts weak optical signals into electrical signals, which are then amplified and output by an anode semiconductor detector. When the device operates, the light being measured is incident on the photocathode, exciting valence band electrons in the cathode material. These electrons transition, diffuse, and escape from the cathode surface to form photoelectrons. These photoelectrons from the cathode surface are focused and accelerated by an electric field, bombarding the surface of the semiconductor detector and generating a large number of electron-hole pairs, achieving electron bombardment gain. These electron-hole pairs are collected by the semiconductor detector and output as an amplified electrical signal corresponding to the optical signal.

[0004] Currently, hybrid photomultiplier tube devices, both domestically and internationally, generally employ a connection method where the anode output is directly connected to the semiconductor detector and the pin via a bonding wire, and then the pin is connected to an external SMA interface via a metal wire. This output method suffers from impedance mismatches between the SMA interface and the pin, and between the pin and the bonding wire, leading to problems such as signal distortion, reflection, and oscillation. For example, the R10467U series recently developed by a certain company has a sub-nanosecond response time, and a reflection peak of a certain amplitude appears after the signal response ends. Summary of the Invention

[0005] The purpose of this invention is to address the defects or deficiencies of the existing technology by providing a coaxial output structure that can be used for hybrid photomultiplier tubes, high-speed signals with low reflection and low oscillation.

[0006] The technical solution to achieve the purpose of this invention is as follows: a coaxial output structure of a hybrid photomultiplier tube based on a microstrip line, wherein the hybrid photomultiplier tube includes a cathode window, a photocathode, a first ceramic ring, a focusing electrode, and a second ceramic ring; the coaxial output structure includes a semiconductor detector and a microstrip structure located inside the photomultiplier tube, and a coaxial structure located outside the photomultiplier tube; the semiconductor detector and the microstrip structure are electrically connected.

[0007] The semiconductor detector is used to receive photoelectrons converted by photocathode and generate current signals;

[0008] The microstrip structure is used to achieve impedance matching in order to reduce signal reflection and oscillation;

[0009] The coaxial structure is used to power the semiconductor detector and output signals.

[0010] Furthermore, the microstrip structure impedance is 50Ω, and the coaxial structure impedance is 50Ω.

[0011] Furthermore, the coaxial structure includes a lead pin, an anode base, and a detector lead pin; the anode base is mounted on the bottom of the second ceramic ring, and the lead pin and the detector lead pin are mounted on the anode base.

[0012] Furthermore, the anode base includes a dielectric and an outer conductor base. The outer conductor base is installed at the bottom of the second ceramic ring. The detector pin is sealed in a first through hole on the outer conductor base through the dielectric. Several second through holes are provided around the first through hole. The pin is sealed in the second through holes through the dielectric. The pin and the detector pin constitute a coaxial inner conductor, and the outer conductor base constitutes a coaxial outer conductor.

[0013] Furthermore, the number of the second through holes and the number of pins are consistent with the number of semiconductor detector output ports, and there is a one-to-one correspondence.

[0014] Furthermore, the microstrip structure includes a microstrip line and a ground electrode, the microstrip line being fixed on the pin and the ground electrode being fixed on the outer conductor base.

[0015] Furthermore, the semiconductor detector and the microstrip structure are electrically connected via bonding wires.

[0016] Furthermore, the semiconductor detector is fixed on the detector pin, and the electrodes of the semiconductor detector are connected to the microstrip line through bonding wires. The signal collected and amplified on the semiconductor detector is finally output with a 50Ω impedance through the bonding wires, microstrip line, pin, and detector pin.

[0017] Furthermore, the semiconductor detector is a PN junction diode, Schottky junction diode, or avalanche photodiode made of silicon, silicon carbide, or other semiconductor materials.

[0018] Furthermore, the microstrip structure is made of nickel- and gold-plated Kovar alloy material, and the coaxial structure is made of Kovar alloy material.

[0019] Compared with the prior art, the significant advantages of this invention are:

[0020] (1) It can effectively suppress reflection and oscillation caused by high-speed signals, and the coaxial structure based on microstrip lines has universality and low manufacturing cost.

[0021] (2) The coaxial structure uses a 50Ω impedance-matched microstrip line inside the hybrid photomultiplier tube, which greatly reduces the length of the bonding wire and effectively suppresses the impedance mismatch caused by the bonding wire.

[0022] (3) A coaxial output structure was designed at the connection between the inside and outside of the tube, and the coaxial structure was encapsulated by glass or ceramic fusion to ensure compatibility with the manufacturing process of the hybrid photomultiplier tube. It is also designed to withstand high temperatures and not generate gas during the high-temperature degassing process. Ultimately, this achieves high-performance transmission of the hybrid photomultiplier tube output signal without oscillation or reflection.

[0023] (4) The microstrip structure is made of nickel-plated and gold-plated Kovar alloy material, and the coaxial structure is made of Kovar alloy material. This satisfies the requirement of no gas release under high temperature conditions required in the high-temperature preparation process of the hybrid photomultiplier tube, and also satisfies the conditions of bonding wire bonding and glass or ceramic sealing.

[0024] (5) The overall microstrip-based hybrid photomultiplier tube coaxial output structure adopts an internal microstrip structure and an external coaxial structure. The microstrip line and coaxial pin are connected by laser welding to form an integrated 50Ω coaxial line, achieving impedance matching. This structure has the advantages of high versatility, simple processing, convenient assembly, low cost, and high reliability.

[0025] The present invention will now be described in further detail with reference to the accompanying drawings. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of a coaxial output structure of a hybrid photomultiplier tube based on microstrip lines in one embodiment.

[0027] Figure 2 This is a schematic diagram of a coaxial structure in one embodiment. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0029] It should be noted that if the embodiments of the present invention involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicators will also change accordingly.

[0030] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. If the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0031] In one embodiment, combined Figures 1 to 2 A coaxial output structure based on a microstrip line hybrid photomultiplier tube is provided. The hybrid photomultiplier tube includes a cathode window 2, a photocathode 3, a first ceramic ring 4, a focusing electrode 5, and a second ceramic ring 6. The coaxial output structure includes a semiconductor detector 13 and a microstrip structure 7 located inside the photomultiplier tube, and a coaxial structure 9 located outside the photomultiplier tube. The semiconductor detector 13 and the microstrip structure 7 are electrically connected.

[0032] The semiconductor detector 13 is used to receive photoelectrons converted by photocathode and generate current signals;

[0033] The microstrip structure 7 is used to achieve impedance matching in order to reduce signal reflection and oscillation;

[0034] The coaxial structure 9 is used to power the semiconductor detector 13 and output signals.

[0035] Furthermore, in one embodiment, the microstrip structure 7 has an impedance of 50Ω, and the coaxial structure 9 has an impedance of 50Ω.

[0036] Furthermore, in one embodiment, the coaxial structure 9 includes a lead pin 14, an anode base 8, and a detector lead pin 16; the anode base 8 is mounted on the bottom of the second ceramic ring 6, and the lead pin 14 and the detector lead pin 16 are mounted on the anode base 8.

[0037] Preferably, in some embodiments, the anode base 8 includes a dielectric 15 and an outer conductor base 17. The outer conductor base 17 is installed at the bottom of the second ceramic ring 6. The detector pin 16 is sealed in a first through hole on the outer conductor base 17 through the dielectric 15. Several second through holes are provided around the first through hole. The pin 14 is sealed in the second through hole through the dielectric 15. The pin 14 and the detector pin 16 constitute a coaxial inner conductor, and the outer conductor base 17 constitutes a coaxial outer conductor.

[0038] Preferably, in some embodiments, the medium 15 is, but not limited to, a sealing material such as glass or ceramic.

[0039] Preferably, in some embodiments, the major and minor dimensions of the medium 15 are calculated based on a 50Ω impedance and material parameters.

[0040] Furthermore, in some embodiments, the number of the second vias and the number of pins 14 are consistent with the number of output ports of the semiconductor detector 13, and there is a one-to-one correspondence. By adopting the scheme of this embodiment, the present invention can be applied to different types of semiconductor detectors 13.

[0041] Furthermore, in one embodiment, the microstrip structure includes a microstrip line 10 and a ground electrode 11, the microstrip line 10 being fixed to the pin 14 and the ground electrode 11 being fixed to the outer conductor base 17.

[0042] Preferably, in some embodiments, the semiconductor detector 13 and the microstrip structure 7 are electrically connected by a bonding wire 12.

[0043] Preferably, in some embodiments, the semiconductor detector 13 is fixed on the detector pin 16, and the electrodes of the semiconductor detector 13 are connected to the microstrip line 10 through the bonding wire 12. The signal collected and amplified on the semiconductor detector 13 is finally output with a 50Ω impedance through the bonding wire 12, the microstrip line 10, the pin 14 and the detector pin 16.

[0044] Preferably, in some embodiments, the microstrip line 10 is fixed to the pin 14 by means of, but not limited to, welding or solder sintering, and the ground electrode 11 is fixed to the outer conductor base 17 by means of, but not limited to, welding or solder sintering. The semiconductor detector 13 is fixed to the detector pin 16 by means of, but not limited to, solder sintering.

[0045] Preferably, in some embodiments, the microstrip line 10, ground electrode 11, pin 14, and detector pin 16 are made of gold-plated Kovar alloy parts, which is beneficial for low-loss signal transmission and meets the degassing requirements of the hybrid photomultiplier tube. The outer conductor base 17 is a Kovar alloy disk, which serves as a support for the anode base 8 and meets the degassing requirements of the hybrid photomultiplier tube.

[0046] Preferably, in some embodiments, the semiconductor detector 13 is a PN junction diode, Schottky junction diode or avalanche photodiode made of silicon, silicon carbide or other semiconductor materials.

[0047] Preferably, in some embodiments, the bonding wire length is less than 2 mm.

[0048] Preferably, in some embodiments, the diameter of the pin portion of the pin 14 and the detector pin 16 is 0.7~1.3mm, which is compatible with 50-ohm coaxial cables.

[0049] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention without departing from its spirit and scope should be included within the protection scope of the present invention.

Claims

1. A coaxial output structure of a hybrid photomultiplier tube based on microstrip lines, wherein the hybrid photomultiplier tube includes a cathode window (2), a photocathode (3), a first ceramic ring (4), a focusing electrode (5), and a second ceramic ring (6), characterized in that, The coaxial output structure includes a semiconductor detector (13) and a microstrip structure (7) located inside the photomultiplier tube, and a coaxial structure (9) located outside the photomultiplier tube; the semiconductor detector (13) and the microstrip structure (7) are electrically connected. The semiconductor detector (13) is used to receive photoelectrons converted by the photocathode and generate a current signal; The microstrip structure (7) is used to achieve impedance matching in order to reduce signal reflection and oscillation; The coaxial structure (9) is used to power the semiconductor detector (13) and output the signal.

2. The coaxial output structure of the microstrip-based hybrid photomultiplier tube according to claim 1, characterized in that, The microstrip structure (7) has an impedance of 50Ω, and the coaxial structure (9) has an impedance of 50Ω.

3. The coaxial output structure of the microstrip-based hybrid photomultiplier tube according to claim 1, characterized in that, The coaxial structure (9) includes a lead pin (14), an anode base (8), and a detector lead pin (16); the anode base (8) is mounted on the bottom of the second ceramic ring (6), and the lead pin (14) and the detector lead pin (16) are mounted on the anode base (8).

4. The coaxial output structure of the microstrip-based hybrid photomultiplier tube according to claim 3, characterized in that, The anode base (8) includes a dielectric (15) and an outer conductor base (17). The outer conductor base (17) is installed at the bottom of the second ceramic ring (6). The detector pin (16) is sealed in a first through hole on the outer conductor base (17) through the dielectric (15). Several second through holes are provided around the first through hole. The pin (14) is sealed in the second through hole through the dielectric (15). The pin (14) and the detector pin (16) constitute a coaxial inner conductor, and the outer conductor base (17) constitutes a coaxial outer conductor.

5. The coaxial output structure of the microstrip-based hybrid photomultiplier tube according to claim 4, characterized in that, The number of the second through holes and the number of pins (14) are consistent with the number of output ports of the semiconductor detector (13), and there is a one-to-one correspondence.

6. The coaxial output structure of the microstrip-based hybrid photomultiplier tube according to claim 4, characterized in that, The microstrip structure includes a microstrip line (10) and a ground electrode (11). The microstrip line (10) is fixed on the pin (14), and the ground electrode (11) is fixed on the outer conductor base (17).

7. The coaxial output structure of the microstrip-based hybrid photomultiplier tube according to claim 6, characterized in that, The semiconductor detector (13) and the microstrip structure (7) are electrically connected by a bonding wire (12).

8. The coaxial output structure of the microstrip-based hybrid photomultiplier tube according to claim 7, characterized in that, The semiconductor detector (13) is fixed on the detector pin (16), and the electrodes of the semiconductor detector (13) are connected to the microstrip line (10) through the bonding wire (12). The signal collected and amplified on the semiconductor detector (13) is finally output with a 50Ω impedance through the bonding wire (12), the microstrip line (10), the pin (14) and the detector pin (16).

9. The coaxial output structure of the hybrid photomultiplier tube based on microstrip lines according to claim 1, characterized in that, The semiconductor detector (13) is a PN junction diode, Schottky junction diode or avalanche photodiode made of silicon, silicon carbide or other semiconductor materials.

10. The coaxial output structure of the microstrip-based hybrid photomultiplier tube according to claim 1, characterized in that, The microstrip structure (7) is made of nickel- and gold-plated Kovar alloy material, and the coaxial structure (9) is made of Kovar alloy material.

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