CN112880974A

CN112880974A - Detection device, clamp and method for influence of MCP reflectivity on cathode sensitivity

Info

Publication number: CN112880974A
Application number: CN202110046945.7A
Authority: CN
Inventors: 李磊; 杨玺文; 宋奇庚; 高海鹏; 李臻; 李金沙; 马怀超; 许有毅; 谭远航; 夏晓娇; 李娇娇; 高兵祥; 朱航; 许灵吉; 郑林涛; 唐顺达; 李家保; 尹昌娟
Original assignee: North Night Vision Technology Co Ltd
Current assignee: North Night Vision Technology Co Ltd
Priority date: 2021-01-14
Filing date: 2021-01-14
Publication date: 2021-06-01
Anticipated expiration: 2041-01-14
Also published as: CN112880974B

Abstract

The invention discloses a detection device, a clamp and a method for the influence of MCP reflectivity on cathode sensitivity. The front assembly consists of a cathode ring, a contact ring, a grid assembly ring, an isolation ring and a ceramic cylinder, and is mainly used for collecting electrons, bearing and sealing a cathode window, a glass window and other parts and forming a micro sealed container. The cathode ring is in a concentric circle shape, the inner ring and the outer ring form a height difference, and the height of the cathode ring is consistent with the thickness of the cathode window body and used for sealing the cathode window. The clamp is integrally in the shape of an inverted concave hollow cylinder and is used for sheathing the lower part of the detection device and ensuring that the input surface of the MCP is tightly attached to the high-transmittance glass window. The method of the invention obtains the measurement value of the sensitivity by calculating the ratio of the photocurrent to the input light flux by means of the device and the clamp. The invention can ensure the influence of MCP on the cathode sensitivity under high vacuum degree inside the tube core.

Description

Detection device, clamp and method for influence of MCP reflectivity on cathode sensitivity

Technical Field

The invention relates to the field of low-light-level image intensifiers, in particular to a device, a clamp and a method for detecting influence of MCP reflectivity on cathode sensitivity.

Background

The low-light-level image intensifier is an imaging device capable of reproducing images and enhancing brightness of extremely weak visible light rays, and is widely applied to the fields of military affairs and scientific research. The sensitivity of the photocathode is an important index of the low-light-level image intensifier, and determines the visual range and the definition of the low-light-level image intensifier under low illumination.

The micro-optical image intensifier consists of a tube core and a special high-voltage power supply, wherein the tube core consists of a photocathode, a micro-channel plate MCP and a fluorescent screen as shown in figure 1 (left). When weak light is incident on the photocathode, the photocathode generates photoelectrons. The electrons are multiplied by the MCP and excite the phosphor screen to produce an image. However, the photocathode has a certain transmittance, and based on the light reflection theory, as shown in fig. 1 (right), if the incident light falling on the end face between the microchannel plate holes can be reflected onto the photocathode again, the photocathode will generate photoelectrons again, and the sensitivity of the image intensifier photocathode can be improved. The reflectivity of the microchannel plate can be increased by coating the microchannel plate, and the need of how to compare the influence of the coated microchannel plate on the sensitivity of the photocathode is urgent in the face of various coated microchannel plates.

On the one hand, the sensitivity of the photo-cathode of the image intensifier is directly influenced by the photo-cathode film layer, so that the same photo-cathode is required to be ensured when the influence of different coated MCPs on the sensitivity of the photo-cathode is compared. However, because the inside of the tube core needs to be kept in a high-vacuum environment, the tube core cannot be disassembled for MCP replacement, and therefore the detection device which can ensure high vacuum degree inside the tube core and can replace the microchannel plate is designed.

On the other hand, the cathode sensitivity of the image intensifier is defined as the ratio of the generated photocurrent to the input light flux of the photocathode under the irradiation of a 2856K standard a light source under the saturated operating voltage of the image tube. The traditional image intensifier detection method is to collect the current on the metal film layer electrode on the input surface of the MCP as the photocurrent generated by the photocathode. However, due to the design reasons, different MCPs need to be replaced, and the photocurrent acquisition mode needs to be considered again, so that a method and a device for acquiring photocurrent, which do not depend on the MCP input surface metal film layer electrode, are needed.

Disclosure of Invention

The invention aims to provide a detection device and a detection method for detecting the influence of MCP reflectivity on cathode sensitivity, which can ensure that the influence of different MCPs on the cathode sensitivity is compared under the condition of high vacuum degree in a tube core. Meanwhile, the requirement of collecting the cathode sensitivity photocurrent of the image intensifier can be met, and effective help is provided for scientific research and production.

The technical scheme of the invention is as follows:

a detection device for detecting the influence of MCP reflectivity on cathode sensitivity comprises a cathode window, a front component and a high-transmittance glass window which are sequentially sealed along the direction of a light path. The front assembly mainly comprises a cathode ring, a contact ring, a grid assembly ring, an isolation ring and a ceramic cylinder, and is mainly used for collecting electrons, bearing and sealing components such as a cathode window, a glass window and the like and forming a micro sealed container as a main channel for the movement of internal electrons. Specifically, the cathode ring and the contact ring, the contact ring and the grid assembly ring, and the grid assembly ring and the isolation ring are separated by a ceramic cylinder and sealed to form a micro sealed container. Along the light path direction, encapsulation is in a ceramic section of thick bamboo both sides around negative pole ring and the contact ring are, and encapsulation is in a ceramic section of thick bamboo both sides around contact ring and the net assembly ring are, and the net assembly ring is the both sides of sealing respectively in a ceramic section of thick bamboo around with the spacing ring.

The cathode ring is in a concentric circle shape, the inner ring and the outer ring form a height difference, the height is consistent with the thickness of a cathode window body, and the cathode ring is mainly used for sealing the cathode window.

In order to ensure that the MCP is replaceable, the MCP is arranged outside the shell of the image intensifier, and the grid assembly ring is designed to replace an MCP input surface electrode to collect electrons generated by a photocathode. The grid assembly ring is in a hollow annular shape, and six strip bulges are arranged on the annular surface and originally used for being in contact with the output surface of the MCP. Four metal wires are welded on the annular surface of the grid assembly ring, and a square metal wire is designed at the annular hollow part and is connected with the annular surface through the four metal wires. The grid mounting ring is designed with contact pins that can be connected to an external sensitive galvanometer. The isolating ring is a hollow circular ring, and is I-shaped in side view, and the isolating ring is sealed with a high-transmittance glass window. In order to eliminate the influence of the overall structure change of the tube shell on the detection result of the influence of the MCP on the cathode sensitivity of the image intensifier, the original designs of a contact ring and the like are reserved.

In order to meet the requirement of a sensitivity test process, the invention is provided with an MCP fixture, wherein the fixture is a hollow cylinder which is integrally in an inverted concave shape, the height of the outer ring of the fixture is about 4cm, and the radius of the fixture is consistent with that of an isolation ring; the middle cylinder was about 2cm high with a radius of about 1/2 f of the outer circle radius.

By means of the device and the clamp, the detection method for detecting the influence of MCP reflection on the cathode sensitivity of the image intensifier comprises the following steps:

during measurement, the MCP input surface is tightly attached to the high-transmittance glass window of the device, and the shell is sleeved by using a clamp. After the glass window is sleeved, the middle cylinder of the clamp supports the output surface of the MCP, so that the input surface of the MCP can be kept close to the high-transmittance glass window.

The grid assembly ring contact pins were connected to a sensitive galvanometer and the device cathode ring was connected to an external power source and applied with-180V as shown in fig. 10. The photocathode generates electrons under the irradiation of a 2856K standard A light source, and the electrons move to the grid assembly ring under the action of an electric field and are captured by the grid. The sensitive photoelectric current meter measures the current on the grid mounting ring as the photocurrent, and calculates the ratio of the photocurrent to the input light flux as the sensitivity measurement. And evaluating the influence of the MCP reflectivity on the cathode sensitivity according to the measured value of the sensitivity obtained by detection, wherein the larger the measured value is, the higher the sensitivity is, and the larger the influence of the MCP reflectivity on the cathode sensitivity is.

The working principle of the invention for realizing detection is as follows:

when the invention is tested, light rays pass through the cathode window to enter the shell and pass through the high-transmittance glass window to irradiate the input surface of the coated MCP. The light is reflected at the input surface of the coated MCP, passes through the glass window again, returns to the interior of the shell and enters the photocathode, and the photocathode can generate photoelectrons again. Therefore, the design can replace different coated MCPs for testing during detection, and can compare the influence of different MCPs on the cathode sensitivity under the conditions of ensuring the consistency of the photocathode and keeping the high vacuum degree in the tube core.

The beneficial effects of the invention include:

1. the invention designs a detection device for detecting the influence of MCP reflectivity on cathode sensitivity, and solves the problem of testing by replacing MCP under the condition of keeping the interior of the device in a vacuum environment through the design of a device structure, a grid assembly ring, a high-transmittance glass window and the like.

2. The design of the device ensures that the same photocathode is used for achieving the premise of controlling variables, the function of collecting electrons is realized through the design of the grid assembly ring, the MCP is arranged outside the high-transmittance glass window of the shell, the purpose of replacing the MCP is realized, and the possibility is provided for comparison test.

3. The invention provides a detection method, designs related clamps, realizes the function of detecting the influence of MCP on the cathode sensitivity of an image intensifier, and provides a test basis for product design and process management.

4. The shell and the test method are greatly adaptive to the existing image intensifier assembly, reliability is high, appearance practicability is good, and product test efficiency is improved.

Drawings

FIG. 1: schematic diagram of principle of low-light level image intensifier (wherein, the left is the principle of common low-light level image intensifier, and the right is the principle of low-light level image intensifier based on light reflection theory).

FIG. 2: and the structural diagram of the shell is used for detecting the influence of the MCP reflectivity on the cathode sensitivity of the image intensifier.

FIG. 3: the cathode ring for the casing is shown schematically in plan view.

FIG. 4: the structure of the image intensifier is schematically shown.

FIG. 5: grid assembly ring schematic view from above.

FIG. 6: the isolation ring seals the high transmittance glass window.

FIG. 7: schematic cross-sectional view of a fixture holding an MCP.

FIG. 8: fixture schematic for holding MCPs.

FIG. 9: schematic diagram of the operation method of the component in the measurement process.

FIG. 10: the MCP has a wiring diagram for measuring the influence of the cathode sensitivity of the image intensifier.

In the figure:

1-cathode window for making photocathode.

2-microchannel plate (MCP). The photocathode generates photoelectrons, the photoelectrons move to the input surface of the MCP under the action of an electric field, are multiplied by the MCP and penetrate out of the output surface of the MCP.

3-microchannel plate (MCP) input face.

4-output surface of micro-channel plate (MCP).

5-fluorescent screen.

6-cathode ring for sealing the cathode window.

7-contact ring. The method is used for collecting the photoelectric current of the MCP input surface electrode in the conventional image intensifier sensitivity measurement process.

8-grid assembly ring. The metal grid is designed for collecting the trapped photoelectrons during sensitivity measurement. As shown in fig. 5.

And 9, forming a ceramic cylinder.

10-spacer ring, used for sealing high-transmittance glass window, fluorescent screen, etc.

11-high transmittance glazing. Light inside the housing reaches the input face of the MCP through the high transmittance glass window. The light is reflected at the input surface, passes through the glass window again, returns to the interior of the shell and is incident to the photocathode.

12-assembly ring. A mounting ring for a conventional image intensifier.

13-touch nail. And the photoelectric current meter is positioned at the edge of the grid assembly ring and is externally connected with a sensitive photoelectric current meter during measurement.

14-a wire. Spot-welding on the assembling ring surface to form the grid assembling ring. For collecting the trapped photoelectrons during measurement.

15-a holder for supporting the MCP.

16-clamp middle cylinder. For supporting the MCP against the high transmittance glazing.

17-sensitive galvanometer. For metering the photocurrent.

Detailed Description

Example 1:

the invention discloses a device for detecting the influence of MCP reflectivity on the cathode sensitivity of an image intensifier, which is shown in figures 1-6.

The device of the invention consists of a front component and a high-transmittance glass window. The front assembly is mainly composed of a cathode ring 6, a contact ring 7, a grid assembly ring 8, a spacer ring 10 and a plurality of ceramic cylinders 9, as shown in fig. 2. It is mainly used for collecting electrons, bearing and sealing cathode window 1, glass window and other parts to form a micro sealed container as the main channel for the movement of internal electrons.

As shown in fig. 3, the cathode ring 6 is concentric, and the inner ring and the outer ring form a height difference, and the height of the inner ring and the outer ring is consistent with the thickness of the cathode window, and the cathode ring is mainly used for sealing the cathode window.

In order to ensure that the MCP is replaceable, the MCP is designed to be arranged outside an image intensifier shell, and a grid assembly ring 8 is designed to replace an MCP input surface electrode to collect electrons generated by a photocathode. The grid assembly ring is designed as shown in fig. 5, and is in a hollow circular ring shape, and six strip bulges are arranged on the annular surface and originally used for being in contact with the output surface of the MCP. Four metal wires 14 are welded on the mesh assembling ring surface, and square metal wires are designed at the annular hollow part and are connected with the ring surface through the four metal wires. The grid mounting ring is designed with contact pins 13 which can be connected to an external sensitive galvanometer 17. The spacer 10 is a hollow circular ring, and has an i-shape in side view, and is sealed with a high transmittance glass window 11, as shown in fig. 6. In order to eliminate the influence of the overall structure change of the tube shell on the detection result of the influence of the MCP on the cathode sensitivity of the image intensifier, the design reserves the original designs of a contact ring and the like.

In order to meet the requirement of the sensitivity testing process, the invention designs a clamp 15 for clamping the MCP. The clamp structure is shown in figures 7 and 8, the whole clamp is an inverted concave hollow cylinder, the height of the outer ring is about 4cm, and the radius of the outer ring is consistent with that of the isolation ring. The middle cylinder 16 is about 2cm high and has a radius of about 1/2 times the radius of the outer ring.

The device of the invention comprises the following components in the manufacturing process:

1. the cathode ring, the contact ring, the isolation ring, the assembly ring, the ceramic cylinder and the high-transmittance glass window are manufactured according to relevant sizes of the image intensifier, and the image intensifier is matched with the existing image intensifier assembly to a great extent.

2. According to the size requirement, the clamp for clamping the MCP is made of rubber materials.

3. Preparing a latticed metal wire, and spot-welding the metal wire on the assembly ring surface to form a latticed assembly ring.

4. And sealing the components according to the sequence of the cathode ring, the ceramic cylinder, the contact ring, the ceramic cylinder, the grid assembly ring, the ceramic cylinder and the isolation ring, and sealing the high-transmittance glass window on the isolation ring.

5. And manufacturing a photocathode on the cathode window in a vacuum environment, and sealing the photocathode on the cathode ring to ensure that the inside of the shell is in a high-vacuum environment.

6. The input surface of the coated MCP is tightly attached to a high-transmittance glass window of the device, and a clamp for clamping the MCP is used for sleeving the shell. The middle cylinder of the clamp supports the output surface of the MCP, and the input surface of the MCP is ensured to be tightly attached to the high-transmittance glass window.

7. The cartridge nested in the fixture was placed in the dark box of the sensitivity meter and a voltage of-180V was applied to the cathode ring using the meter's external power supply. A sensitive galvanometer is attached to the grid fitting ring contact pin.

8. The dark box was turned off, the photocathode was illuminated with a 2856K standard a light source, the sensitive galvanometer was statistically read and the corresponding cathode sensitivity was calculated.

9. And taking out the measured tube shell, taking down the clamp for clamping the MCP, and replacing the MCP for measurement again.

The effect of MCP on image intensifier cathode sensitivity was counted versus cathode sensitivity measured with different or no MCPs. Higher sensitivity indicates a greater influence of MCP reflectivity on cathode sensitivity.

Example 2:

the invention discloses a detection method for detecting influence of MCP reflection on cathode sensitivity of an image intensifier, which comprises the following steps:

step 1, the MCP input surface 3 is tightly attached to the high-transmittance glass window 11, and the shell is sleeved by using a clamp 15. After being sleeved, the middle cylinder 16 of the clamp supports the output surface 4 of the MCP, and ensures that the input surface of the MCP is kept close to the high-transmittance glass window.

Step 2, connecting the grid assembly ring contact pin 13 with a sensitive photoelectric current meter 17, connecting the cathode ring with an external power supply and applying a voltage of-180V, as shown in FIG. 10. The photocathode generates electrons under the irradiation of a 2856K standard A light source, and the electrons move to the grid assembly ring under the action of an electric field and are captured by the grid.

And 3, measuring the current on the grid assembly ring by using a sensitive photoelectric current meter to serve as a photocurrent, and calculating the ratio of the photocurrent to the input luminous flux to serve as a sensitivity measurement value.

And 4, evaluating the influence of the MCP reflectivity on the cathode sensitivity according to the measured value of the detected sensitivity, wherein the larger the measured value is, the higher the sensitivity is, and the larger the influence of the MCP reflectivity on the cathode sensitivity is.

Claims

1. A detection device for detecting influence of MCP reflectivity on cathode sensitivity is characterized in that:

consists of a cathode window (1), a front component and a high-transmittance glass window (11); along the direction of the light path, the cathode window (1) is sealed in front of the front component, and the high-transmittance glass window (11) is sealed in back of the front component;

the front assembly mainly comprises a cathode ring (6), a contact ring (7), a grid assembly ring (8), an isolation ring (10) and a ceramic cylinder (9); the cathode ring (6) and the contact ring (7), the contact ring (7) and the grid assembly ring (8), and the grid assembly ring (8) and the isolation ring (10) are separated by a ceramic cylinder (9), sealed and connected together to form a micro sealed container which is used as a main channel for internal electron movement;

the cathode ring (6) is concentric and used for sealing the cathode window (1), and the inner ring and the outer ring form a height difference which is consistent with the thickness of the cathode window (1).

2. The detection device according to claim 1, wherein:

along the light path direction, encapsulation in a ceramic section of thick bamboo (9) both sides around negative pole ring (6) and contact ring (7) are, encapsulation in a ceramic section of thick bamboo (9) both sides around contact ring (7) and net assembly ring (8) are, seal respectively in the both sides of a ceramic section of thick bamboo (9) around net assembly ring (8) and spacing collar (10) are.

3. The detection device according to claim 1 or 2, wherein:

the grid assembly ring (8) is in a hollow circular ring shape, and six strip bulges are arranged on the annular surface of the grid assembly ring and are used for being in contact with the MCP output surface.

4. The detection device according to claim 3, wherein:

the annular surface of the grid assembling ring (8) is welded with four metal wires (14), a square metal wire is arranged at the annular hollow part of the grid assembling ring, and the grid assembling ring is connected with the annular surface of the grid assembling ring (8) through the four metal wires.

5. The detection device according to claim 1 or 2, wherein:

the isolating ring (10) is a hollow circular ring, is I-shaped in side view, and is sealed with a high-transmittance glass window (11).

6. The detection device according to claim 4, wherein:

the grid assembly ring (8) is also provided with a contact pin (13) connected with an external sensitive photoelectric current meter (17).

7. A jig for fixing the detecting device according to any one of claims 1 to 6, characterized in that:

the clamp (15) is a hollow cylinder which is integrally in an inverted concave shape, a middle cylinder (16) is arranged on the inner bottom surface of the hollow cylinder, the height of the outer ring of the clamp (15) is 4cm, and the radius of the clamp is consistent with that of the isolation ring (10); the height of the middle cylinder (16) is 2cm, and the radius of the middle cylinder is 1/2 of the radius of the outer ring.

8. Method for detecting the influence of MCP reflectivity on the sensitivity of a cathode using a detection device according to any one of claims 1 to 6 and a holder according to claim 7, characterized in that it comprises the following steps:

step 1, an MCP input surface (3) is tightly attached to a high-transmittance glass window (11), the lower part of a detection device for detecting the influence of MCP reflectivity on cathode sensitivity is sleeved by a clamp (15), and a middle cylinder (16) of the clamp (15) supports an MCP output surface (4) to ensure that the input surface of the MCP output surface is tightly attached to the high-transmittance glass window (11);

step 2, connecting the grid assembly ring contact nail (13) with a sensitive photoelectric current meter (17), connecting the cathode ring (6) with an external power supply and applying-180V voltage; the photocathode generates electrons under the irradiation of a 2856K standard A light source, and the electrons move to and are captured by the grid assembly ring (8) under the action of an electric field;

step 3, a sensitive photoelectric current meter (17) measures the current on the grid assembly ring (8) to be used as the photocurrent, and the ratio of the photocurrent to the input light flux is calculated to be used as the measured value of the sensitivity;