CN116770231A - Evaporation device for photomultiplier tube coating and its manufacturing method and device, as well as evaporation method and device for optical window coating - Google Patents

Abstract

The present invention relates to the technical field of photomultiplier tube processing, and specifically to an evaporation device for photomultiplier tube coating and its manufacturing method and device, as well as an evaporation method and device for optical window coating, including: evaporation electrodes, including positive electrodes and negative electrodes. ; Evaporation source structure, the first end of the evaporation source structure is connected to the positive electrode, and the second end of the evaporation source structure is connected to the negative electrode; the evaporation material layer is connected to the evaporation source structure; wherein, The evaporation source structure includes an evaporation surface, and the evaporation material layer is connected to the evaporation surface. The advantages of the surface evaporation source are used to improve the uniformity of the coating, thereby improving the uniformity of the quantum efficiency of the device. Moreover, the coating direction of the sheet surface evaporation device only faces the glass light window, and other directions are blocked by its own evaporation source sheet. It will not evaporate to locations such as ceramics that do not require coating, which can improve the noise characteristics of the entire tube.

Description

Evaporation device for photomultiplier tube coating and its manufacturing method, device and light Evaporation method and device for window coating

Technical field

The present invention relates to the technical field of photomultiplier tube processing, and specifically to an evaporation device for photomultiplier tube coating and its manufacturing method and device, as well as an evaporation method and device for optical window coating.

Background technique

The coating layer on the light window of the photomultiplier tube includes anti-reflection coating and photocathode film. Cathode quantum efficiency is one of the key performance indicators that determines its photodetection capabilities. The key to the production of photomultiplier tube cathodes is the plating of optical anti-reflection coatings and photoelectric emission coatings. The thickness of the antireflection coating and the photoelectric emission coating largely determines the cathode quantum efficiency. Therefore, the uniformity of the thickness of the antireflection coating and the photoelectric emission coating also determines the uniformity of the cathode quantum efficiency.

As shown in Figure 1, the traditional anti-reflection film preparation method for cathode production: using tantalum wire loaded with metal manganese balls as an evaporation device, loading the tantalum wire with current to cause it to heat up, and evaporating the metal balls onto the glass window of the photomultiplier tube. And oxygen is passed through for oxidation to obtain a metal oxide antireflection coating. Similarly, the production of photoelectric emission film layer uses nickel wire or platinum-coated molybdenum wire to load metal antimony balls as an evaporation device, and a current is applied to evaporate the antimony beads onto the glass light window.

The above antireflection coating and antimony film evaporation methods all use point evaporation sources as evaporation devices. In this evaporation method, the film layer is often thicker at locations closer to the point evaporation source, so there is a large difference in film thickness uniformity. Secondly, the direction of the coating of the spherical evaporation source is not selective. When the film is coated on the glass window, the film is also coated on the ceramic sheet, glass wall, focusing pole and other positions of the photomultiplier tube, resulting in Problems such as inter-electrode ohmic leakage of the device and increased thermal electron emission noise.

Contents of the invention

The first aspect of the present invention proposes a technical solution, an evaporation device for photomultiplier tube coating, including:

Evaporation electrodes, including positive and negative electrodes;

An evaporation source structure, a first end of the evaporation source structure is connected to the positive electrode, and a second end of the evaporation source structure is connected to the negative electrode;

a layer of evaporation material connected to the evaporation source structure;

Wherein, the evaporation source structure includes an evaporation surface, the evaporation material layer is connected to the evaporation surface, the evaporation surface faces the direction of the structure to be coated, and the evaporation surface faces the direction of the structure to be coated, the evaporation material layer The thickness is the same;

When the positive electrode and the negative electrode are connected to the driving circuit, the evaporation source structure generates heat, causing the evaporation material layer to evaporate to form a coating layer on the surface of the structure to be coated.

Preferably, the shape of the evaporated material layer matches the shape of the structure to be coated.

Preferably, the evaporation source structure is constructed in a sheet shape, and the sheet-shaped evaporation source structure is provided with the evaporation surface. The shape of the evaporation surface matches the shape of the structure to be coated. The evaporation source structure has Uniform thickness.

Preferably, the evaporation source structure is configured in a semicircular ring shape or a right-angled strip shape.

Preferably, the evaporation source structures are arranged in a pair and are arranged symmetrically, and two evaporation source structures are connected to the driving circuit in parallel.

Preferably, the evaporation source structure includes tantalum, tungsten or platinum materials.

Preferably, the evaporation material layer is evaporated onto the evaporation surface of the evaporation source structure by magnetron sputtering or electron beam evaporation.

A second aspect of the present invention proposes a technical solution, a method for manufacturing an evaporation device for photomultiplier tube coating, which is characterized in that it includes the following steps:

S1. Make the evaporation source structure:

S11. According to the shape of the structure to be coated, form a metal sheet that matches the shape of the structure to be coated;

S2. Make the evaporation material layer:

Step S21: Pre-evaporate the evaporation material onto the surface of the metal sheet through a high-precision coating method according to the thickness of the coating process of the structure to be coated, and form a predetermined thickness;

Among them, high-precision coating methods include magnetron sputtering or electron beam evaporation.

Preferably, in step S21, controlling the thickness of the evaporated material includes the following steps:

Create a vacuum environment and fill it with argon;

Control the magnetron sputtering target to emit coating material to a predetermined area;

The evaporation source structure reciprocates through the target sputtering area at a predetermined speed;

Among them, the speed and number of sputtering of the evaporation source structure through the target material are controlled so that the thickness of the evaporation material layer formed on the surface of the evaporation source structure reaches the target thickness.

The third aspect of the present invention proposes a technical solution, a manufacturing device for an evaporation device for photomultiplier tube coating, including:

Coating machine cavity, the coating machine cavity is used to construct a coating environment;

A magnetron sputtering target is arranged in the coating machine cavity, and the magnetron sputtering target is used to emit coating material to the sputtering area;

A track is set into the coating machine cavity and passes through the sputtering area;

A tray for holding a plurality of the evaporation source structures, the tray is connected to a track, and the tray can reciprocate along the track to enter or leave the sputtering area of the magnetron sputtering target;

Wherein, the track is configured to drive the tray through the sputtering area at a predetermined speed to control the length of time the evaporation source structure is in the sputtering area.

The fourth aspect of the present invention proposes a technical solution, an evaporation method for photomultiplier tube optical window coating, which includes the following steps:

Step a. Manufacture and form a first film layer evaporation device and a second film layer evaporation device according to the above-mentioned manufacturing method of an evaporation device for photomultiplier tube coating;

Step b. Connect the positive electrodes of the first film layer evaporation device and the second film layer evaporation device to the first positive electrode terminal and the second positive electrode terminal respectively. The first film layer evaporation device and the second film layer evaporation device The negative electrode of the device is connected to the focusing electrode of the photomultiplier tube;

Step c. Load current to the first positive terminal and the focusing electrode of the photomultiplier tube to form a first film layer on the surface of the light window, and then load current to the second positive terminal and the focusing electrode of the photomultiplier tube to form a first film layer on the surface of the light window. Form a second film layer;

Wherein, the metal target material of the first evaporation device includes manganese and titanium, and the metal target material of the second evaporation device includes antimony and tellurium.

Preferably, when preparing the first film layer evaporation device, the following process is followed: the manganese target sputtering power is set to 15-20W/cm ² , the movement speed of the workpiece disk is 6mm/s, and the number of reciprocations is 4-5 times;

When preparing the second film layer evaporation device, follow the following process: the antimony target sputtering power is set to 10-15W/cm ² , the movement speed of the workpiece disk is 8mm/s, and the number of reciprocations is 3-4 times.

The fifth aspect of the present invention proposes a technical solution, an evaporation device for photomultiplier tube optical window coating, including:

The focusing electrode of the photomultiplier tube;

glass light windows;

The first film layer evaporation device includes a pair of the above-mentioned evaporation devices for photomultiplier tube coating;

The second film layer evaporation device includes a pair of the above-mentioned evaporation devices for photomultiplier tube coating;

Two positive terminals, connected to the focusing electrode of the photomultiplier tube;

The first end of the first film layer evaporation device is connected to the first positive terminal through the positive lead, and the second end is connected to the focusing electrode of the photomultiplier tube;

The first end of the second film layer evaporation device is connected to the second positive terminal through the positive lead, and the second end is connected to the focusing electrode of the photomultiplier tube;

Wherein, a pair of evaporation devices for photomultiplier tube coating in the first film layer evaporation device are symmetrically distributed around the axis of the glass light window;

Among the second film layer evaporation devices, a pair of evaporation devices for photomultiplier tube coating are symmetrically distributed around the axis of the glass light window.

Compared with the prior art, the advantages of the present invention are:

The present invention proposes a sheet surface evaporation device, which can flexibly adjust the shape of the sheet surface evaporation device according to the geometric shape of the photomultiplier tube light window, and utilizes the advantages of the surface evaporation source to improve the uniformity of its coating, thereby improving the quantum performance of the device. Efficiency uniformity. Moreover, the coating direction of the sheet surface evaporation device only faces the glass light window, and other directions are blocked by its own evaporation source sheet. It will not evaporate to locations such as ceramics that do not require coating, which can improve the noise characteristics of the entire tube.

In addition, the evaporation material on the sheet surface evaporation device is pre- quantitatively deposited on the evaporation source sheet through magnetron sputtering or electron beam evaporation, and is in a thin film state. Therefore, when using a sheet surface evaporation device for coating, there will be no explosion problems like antimony bead coating, and the evaporation rate and film thickness are controllable and adjustable; after the coating is completed, the evaporation material on the sheet is almost All will be evaporated, so there will be no problem of evaporated materials falling to form foreign matter or causing short circuit between electrodes, ensuring that the device has good impact and vibration resistance.

Description of drawings

The drawings are not intended to be drawn to scale. In the drawings, each identical or approximately identical component shown in various figures may be designated by the same reference numeral. For clarity, not every component is labeled in each figure. Embodiments of various aspects of the invention will now be described by way of example and with reference to the accompanying drawings, in which:

Figure 1 is a schematic diagram of using a point evaporation source as an evaporation device to coat a glass light window in the prior art;

Figure 2 is a schematic cross-sectional structural diagram of the evaporation device shown in the present invention;

Figure 3 is a schematic diagram of the evaporation device shown in the present invention configured as a double semicircular ring structure;

Figure 4 is a schematic diagram of the evaporation device shown in the present invention configured as a double right-angled strip structure;

Figure 5 is a schematic structural diagram of the manufacturing device of the evaporation device shown in the present invention;

Figure 6 is a schematic structural diagram of an evaporation device used for photomultiplier tube light window coating according to the present invention;

Figure 7a is a quantum efficiency distribution diagram of a photomultiplier tube prepared by a metal wire-loaded spherical evaporation source device;

Figure 7b is a quantum efficiency distribution diagram of the photomultiplier tube prepared in this embodiment.

Detailed ways

In order to better understand the technical content of the present invention, specific embodiments are described below along with the accompanying drawings.

As shown in Figure 1, the traditional anti-reflection film preparation method for cathode production: using tantalum wire loaded with metal manganese balls as an evaporation device, loading the tantalum wire with current to cause it to heat up, and evaporating the metal balls onto the glass window of the photomultiplier tube. And oxygen is passed through for oxidation to obtain a metal oxide antireflection coating. Similarly, the production of photoelectric emission film layer uses nickel wire or platinum-coated molybdenum wire to load metal antimony balls as an evaporation device, and a current is applied to evaporate the antimony beads onto the glass light window.

The above antireflection coating and antimony film evaporation methods all use point evaporation sources as evaporation devices. In this evaporation method, the film layer is often thicker at locations closer to the point evaporation source, so there is a large difference in film thickness uniformity. Secondly, the direction of the coating of the spherical evaporation source is not selective. When the film is coated on the glass window, the film is also coated on the ceramic sheet, glass wall, focusing pole and other positions of the photomultiplier tube, resulting in Problems such as inter-electrode ohmic leakage of the device and increased thermal electron emission noise.

Furthermore, when metal balls are used as the evaporation material for coating, the evaporation rate is often uncontrollable, and the metal balls often evaporate or explode explosively, resulting in uncontrollable coating thicknesses of antireflection coatings and metal antimony films. What's more serious is that when metal wire-coated metal antimony balls are used as evaporation devices, more than half of the metal antimony balls are often left after the antimony film evaporation is completed. During the subsequent photocathode activation process, the remaining metal antimony balls It will absorb potassium, sodium, and cesium alkali metals and expand rapidly and become loose, unable to adhere firmly to its metal wires. When the photomultiplier tube is subjected to impact and vibration, the loose antimony balls will peel off from the metal wire, forming foreign matter in the tube and causing a short circuit between the electrodes, resulting in device failure and failure.

Therefore, the first aspect of this application proposes an evaporation device for photomultiplier tube coating. It is a sheet-shaped evaporation device that mainly uses the characteristics of the surface evaporation source to improve the structure to be plated, especially the photomultiplier tube. The uniformity of the coating of the light window, thereby improving the uniformity of the quantum efficiency of the photomultiplier tube.

In addition, the shape of the sheet-shaped surface evaporation device can be flexibly adjusted according to the shape of the photomultiplier tube light window to adapt to different light window shapes, such as circular or rectangular light windows.

Secondly, the coating direction of the sheet surface evaporation device only faces the glass light window, and other directions are blocked by its own evaporation source sheet. It will not evaporate to locations such as ceramics that do not require coating, which can improve the noise characteristics of the entire tube.

In addition, the evaporation material on the sheet surface evaporation device is pre- quantitatively deposited on the evaporation source sheet through magnetron sputtering or electron beam evaporation. Therefore, when using the sheet surface evaporation device for coating, the evaporation rate and film The thickness is controllable and adjustable.

What's more important is that with this sheet-shaped surface evaporation device, after completing the photomultiplier tube coating, the evaporation material will almost all be evaporated, so there will be no problem of the evaporation material falling to form foreign matter or causing an inter-electrode short circuit. Ensure that the device has good impact and vibration resistance.

[Evaporation device for photomultiplier tube coating]

As shown in Figures 2-4, the present invention proposes a technical solution in the first aspect, an evaporation device for photomultiplier tube coating, including an evaporation electrode, an evaporation source structure 11 and an evaporation material layer 12. The evaporation electrode includes The positive electrode and the negative electrode, the first end of the evaporation source structure 11 is connected to the positive electrode, the second end of the evaporation source structure 11 is connected to the negative electrode, and the evaporation material layer 12 is connected to the evaporation source structure 11 .

Specifically, the evaporation source structure 11 is intended to provide the evaporation material layer 12 with the heat required for evaporation. Therefore, the evaporation source structure 11 is usually made of a metal material with a high melting point, such as tantalum, tungsten, platinum and other metal materials. into a thin sheet, with electrodes formed at both ends. When a certain current is applied to both ends, the evaporation source structure 11 generates heat, and the evaporation material layer 12 attached to the surface of the evaporation source structure 11 is evaporated using the heat.

The evaporation source structure 11 includes an evaporation surface, and the evaporation material layer 12 is connected to the evaporation surface. The evaporation surface faces the direction of the structure to be coated, and the thickness of the evaporation material layer is the same from the evaporation surface to the direction of the structure to be coated.

In this way, when the positive electrode and the negative electrode are connected to the driving circuit, the evaporation source structure 11 generates heat, causing the evaporation material layer 12 to evaporate to form a coating on the surface of the structure to be coated.

It can be understood that compared with the spherical evaporation source in the prior art, this form of surface evaporation has the advantages of controllable direction and controllable evaporation amount.

In addition, the evaporation material layer 12 is made of different materials depending on the coating material. For optical window coating, it generally includes an anti-reflection coating layer and a photoelectric emission layer. Among them, the anti-reflection coating layer generally uses manganese, titanium, aluminum and other materials. , the photoelectric emission layer generally uses antimony, tellurium, iodine and other materials. In this application, the evaporation device used to manufacture the anti-reflection coating layer is called the first film layer evaporation device, and the evaporation device used to manufacture the photoelectric emitting layer is called the third film layer evaporation device. Two-layer evaporation device.

Further, in order to control the evaporation material to accurately adhere to a predetermined area of the structure to be coated, the shape of the evaporation material layer 12 matches the shape of the structure to be coated. In this way, after the evaporation source structure 11 generates heat, the evaporation material layer 12 moves toward the direction corresponding to the evaporation surface toward the structure to be coated, and adheres to the corresponding area of the structure to be coated. In this way, the evaporation material can be accurately controlled on the surface of the structure to be coated. Create coating coverage.

Further, in order to control the evaporation material layer 12 to be uniformly heated and evaporate, the evaporation source structure 11 is constructed in a sheet shape. The sheet-shaped evaporation source structure is provided with an evaporation surface, and the shape of the evaporation surface matches the shape of the structure to be coated. The evaporation source The thickness of structure 11 is uniform.

In this way, when the evaporation source structure 11 is powered on, the heat generated on its surface is uniform, and the evaporation material layer 12 on the entire evaporation surface can be uniformly evaporated.

In an optional embodiment, for the circular or spherical light window of the photomultiplier tube, the shape of the evaporation source structure 11 and the evaporation material layer 12 on its surface is a double semicircular ring shape, as shown in Figure 3 for the photomultiplier tube For the square light window coating, the shape of the evaporation source structure 11 and the evaporation material layer 12 on its surface is a right-angled strip, as shown in Figure 4.

Figure 3 shows a pair of semi-circular ring-shaped first film layer evaporation devices 100a and 100b, with positive electrodes 101 and negative electrodes 102 respectively formed at both ends. Figure 4 shows a pair of right-angled strip-shaped first film layer evaporation devices. The two ends of the plating devices 200a and 200b are respectively formed with a positive electrode 201 and a negative electrode 202.

Preferably, the evaporation source structures 11 are arranged in a pair and are arranged symmetrically, and the two evaporation source structures 11 are connected to the driving circuit in parallel.

In this way, the heat of the two evaporation source structures 11 can be consistent, and the evaporation material layer 12 can be efficiently evaporated to the surface of the light window to form a coating.

In the above embodiment, in order to accurately control the thickness of the evaporation material layer 12, that is, the amount of evaporation material required for coating, the evaporation material layer 12 is evaporated to the evaporation source structure by magnetron sputtering or electron beam evaporation. 11 evaporation surface.

In this way, the evaporation material layer 12 is quantitatively deposited on the evaporation source structure 11 in advance through magnetron sputtering or electron beam evaporation, and is in a thin film state. Therefore, when using a sheet surface evaporation device for coating, there will be no antimony bead coating. Such an explosion problem, the evaporation rate and film thickness are both controllable and adjustable. And after the coating is completed, almost all the evaporated materials on the sheet will be evaporated, so there will be no problems of the evaporated materials falling to form foreign objects or causing short circuits between electrodes, ensuring that the device has good impact and vibration resistance.

[Method for manufacturing evaporation device for photomultiplier tube coating]

A second aspect of the present invention proposes a technical solution, a method for manufacturing an evaporation device for photomultiplier tube coating, which is characterized in that it includes the following steps:

S1. Make the evaporation source structure 11:

S11. According to the shape of the structure to be coated, form a metal sheet that matches the shape of the structure to be coated;

S2. Make the evaporation material layer 12:

Step S21: Pre-evaporate the evaporation material onto the surface of the metal sheet through a high-precision coating method according to the thickness of the coating process of the structure to be coated, and form a predetermined thickness;

Among them, high-precision coating methods include magnetron sputtering or electron beam evaporation.

It can be understood that according to the shape of the structure to be coated (such as optical window glass), high melting point metals (tantalum, tungsten, platinum, etc.) are used to make sheet structures of corresponding shapes, and then multiple sheets are jointly placed on a tray. The tray as a whole is passed through the evaporation area of magnetron sputtering or electron beam evaporation.

Magnetron sputtering or electron beam evaporation are both high-precision coating methods. In this way, the thickness of the evaporation material layer 12 on the evaporation source structure 11 can be accurately controlled to ensure that no evaporation material will fall off after the evaporation is completed. It prevents foreign matter from falling or causing short circuit between poles, ensuring that the device has good impact and vibration resistance.

Preferably, in step S21, controlling the thickness of the evaporated material includes the following steps:

Create a vacuum environment and fill it with process gas argon, which provides the Ar ion source;

Control the magnetron sputtering target to emit coating material to a predetermined area;

The evaporation source structure 11 reciprocates through the target sputtering area at a predetermined speed;

Among them, the speed and number of times that the evaporation source structure 11 is sputtered by the target material is controlled so that the thickness of the evaporation material layer 12 formed on the surface of the evaporation source structure 11 reaches a target thickness.

Specifically, as shown in FIG. 5 , the sheet-shaped evaporation source 100 to be coated is laid flat on the workpiece tray 400 , and the workpiece tray 400 is installed on the slide rail 500 of the coating machine. Start the vacuum acquisition system of the coating machine and pre-evacuate until the vacuum degree is better than 1E-3Pa. Pour in Ar and keep the vacuum in the coating machine cavity at 0.2Pa ~ 0.8Pa. The movement speed of the workpiece disk is set to 6 to 18 mm/s, and the workpiece disk moves along the slide rail to the bottom of the target 300 for reciprocating sputtering coating, thereby depositing a layer of thin film evaporation material on the surface of the sheet evaporation source 100 .

It can be understood that under the same sputtering power, the faster the movement speed of the workpiece disk, the thinner the coating layer.

Therefore, precise control of coating thickness can be achieved by adjusting the movement speed of the workpiece disk and the number of reciprocating movements of the workpiece disk. Optional, the coating thickness is generally 50nm~300nm.

[Fabrication device for evaporation device for photomultiplier tube coating]

As shown in FIG. 5 , the third aspect of the present invention proposes a technical solution, a manufacturing device for an evaporation device for photomultiplier tube coating, including:

Coating machine chamber 600. The coating machine chamber 600 is used to construct a coating environment, such as a vacuum degree of 0.2Pa to 0.8Pa;

The magnetron sputtering target 300 is arranged in the coating machine cavity 600. The magnetron sputtering target 300 is used to emit coating materials to the sputtering area;

The track 500 is set in the coating machine chamber 600 and passes through the sputtering area;

The tray 400 is used to hold multiple sheet evaporation sources 100. The tray 400 is connected to the track 500. The tray 400 can reciprocate along the track 500 to enter or leave the sputtering area of the magnetron sputtering target;

The track 500 is configured to drive the tray 400 through the sputtering area at a predetermined speed to control the length of time the evaporation source structure 11 is in the sputtering area.

In a specific embodiment, a semicircular annular sheet surface evaporation device is produced for coating of circular light windows, wherein a first film layer evaporation device 100a and a second film layer evaporation device need to be produced. 100c.

Magnetron sputtering is used to produce a semicircular annular sheet surface evaporation device. The preparation process is as follows:

The sheet-shaped evaporation source 100 to be coated is laid flat on the workpiece tray 400, and the workpiece tray 400 is installed on the slide rail 500 of the coating machine. Start the vacuum acquisition system of the coating machine and pre-evacuate until the vacuum degree is better than 1E-3Pa. Pour in Ar and keep the vacuum in the coating machine cavity at 0.2Pa ~ 0.8Pa. The movement speed of the workpiece disk is set to 6 to 18 mm/s, and the workpiece disk moves along the slide rail to the bottom of the target 300 for reciprocating sputtering coating, thereby depositing a layer of thin film evaporation material on the surface of the sheet evaporation source 100 .

Optional, the coating thickness is generally 50nm~300nm.

(a) Preparation of sheet surface evaporation device for anti-reflection coating preparation

When making a sheet surface evaporation device for preparing an anti-reflection film, the material of the magnetron sputtering target 300 is a metal target such as manganese or titanium. Taking the manganese target as an example, the sputtering power is set to 15~20W/ ^cm2 , the movement speed of the workpiece disk is set to 6mm/s, and the number of reciprocations is 4~5 times.

(b) Preparation of sheet surface evaporation device for cathode photoemitting layer

When making a sheet surface evaporation device for preparing a cathode photoemitting layer, the magnetron sputtering target 300 is made of target materials such as antimony and tellurium. Taking the antimony target as an example, the sputtering power is set to 10~15W/ ^cm2 , the movement speed of the workpiece disk is set to 8mm/s, and the number of reciprocations is 3~4 times.

[Vapor deposition method for photomultiplier tube optical window coating]

The fourth aspect of the present invention proposes a technical solution, an evaporation method for photomultiplier tube optical window coating, which includes the following steps:

Step a. Manufacture and form a first film layer evaporation device and a second film layer evaporation device according to the above-mentioned manufacturing method of an evaporation device for photomultiplier tube coating;

Step b. Connect the positive electrodes of the first film layer evaporation device and the second film layer evaporation device to the first positive electrode terminal and the second positive electrode terminal respectively. The first film layer evaporation device and the second film layer evaporation device The negative electrode of the device is connected to the focusing electrode of the photomultiplier tube;

Step c. Load current to the first positive terminal and the focusing electrode of the photomultiplier tube to form a first film layer on the surface of the light window, and then load current to the second positive terminal and the focusing electrode of the photomultiplier tube to form a first film layer on the surface of the light window. Form a second film layer;

The metal target of the first evaporation device includes manganese, titanium, etc., and the metal target of the second evaporation device includes antimony, tellurium, etc.

Optionally, when preparing the first film layer evaporation device, follow the following process: the manganese target sputtering power is set to 15~20W/cm ² , the movement speed of the workpiece disk is 6mm/s, and the number of reciprocations is 4~5 times. ;

When preparing the second film layer evaporation device, follow the following process: the antimony target sputtering power is set to 10-15W/cm ² , the movement speed of the workpiece disk is 8mm/s, and the number of reciprocations is 3-4 times.

[Evaporation device for photomultiplier tube optical window coating]

As shown in FIG. 6 , the fifth aspect of the present invention proposes a technical solution, an evaporation device for photomultiplier tube light window coating, including a first film layer evaporation device 100 a and a second film layer evaporation device 100 c , the focusing electrode 700 of the photomultiplier tube, the glass light window 800, the positive lead 900 and the positive terminal 901. Among them, the first film layer evaporation device 100a is used to evaporate and form an anti-reflection film on the inner surface of the glass light window 800, and the second film layer evaporation device 100c is used to evaporate and form a metal antimony film on the inner surface of the glass light window 800.

As shown in FIG. 6 , the first film layer evaporation device 100a and the second film layer evaporation device 100c are arranged to be nested inside or outside each other, which can ensure the uniformity of the two layers of coating. Moreover, a pair of evaporation devices in the first film layer evaporation device 100a and the second film layer evaporation device 100c are symmetrically distributed around the glass light window 800. In this way, it can be ensured that after the two evaporation source structures 11 are energized, their surfaces The evaporation material layer 12 is uniformly evaporated to a predetermined area of the glass light window 800, so that the formed coating film is uniform and the coating range falls into a predetermined range.

The assembly and evaporation process of the evaporation device are explained in detail using the antireflection film evaporation device.

The first end of the first film layer evaporation device 100a is connected to the positive electrode terminal 901 of the anti-reflection film evaporation deposition through the positive electrode lead 900 tantalum wire, and is led out of the photomultiplier tube through the lead wire. The other end of the first film evaporation device 100a is welded to the focusing electrode 700 of the photomultiplier tube, and the focusing electrode 700 of the photomultiplier tube is used as the negative electrode of the first film evaporation device 100a.

A certain current is loaded through the positive terminal 901 and the focusing electrode 700 of the photomultiplier tube, and the electrothermal effect is used to cause the first film layer evaporation device 100a to heat itself, thereby evaporating the evaporation material on the surface onto the glass light window 800, forming a third film layer evaporation device 100a. One film layer is the anti-reflection coating.

The coating structure and principle of the metal antimony film of the second film layer are the same as those of the first film layer. The first end of the second film layer evaporation device 100c is connected to the positive electrode terminal 901 of the antireflection film evaporation through the positive electrode lead 900 tantalum wire. , and lead out to the outside of the photomultiplier tube through leads. The other end of the second film evaporation device 100c is welded to the focusing electrode 700 of the photomultiplier tube, and the focusing electrode 700 of the photomultiplier tube is used as the negative electrode of the second film evaporation device 100c.

A certain current is loaded through the positive terminal 901 and the focusing electrode 700 of the photomultiplier tube, and the electrothermal effect is used to cause the second film layer evaporation device 100c to heat itself, thereby evaporating the evaporation material on the surface onto the glass light window 800, forming a second film layer evaporation device 100c. The second film layer is the metal antimony film.

Further, coating and cathode activation include the following steps:

The first film layer evaporation device 100a and the second film layer evaporation device 100c are assembled into the photomultiplier tube to replace the original manganese and antimony spherical evaporation devices respectively. According to the photomultiplier tube manufacturing process, the manganese is first evaporated, the evaporation current is set to 5 to 10A, and the size is evaporated for 1 to 2 minutes; then oxygen is injected into the photomultiplier tube to oxidize the manganese into a manganese oxide antireflection film.

After completing the preparation of the antireflection film, the vacuum in the photomultiplier tube is evacuated to below 1E-4Pa, and then antimony and alkali metal activation are performed. The antimony evaporation current is 2 to 4 A, and the evaporation is continued for 2 to 5 minutes, and then the alkali metal K and Cs are activated in sequence.

Furthermore, the cathode quantum efficiency at 16 points on the cathode surface of the photomultiplier tube manufactured using different evaporation devices was measured. Figure 7a is a photomultiplier tube quantum efficiency distribution diagram using the surface evaporation device disclosed in this embodiment. Figure 7b is a photomultiplier tube quantum efficiency distribution diagram using a traditional conventional metal wire loaded spherical evaporation source device.

It can be seen that the quantum efficiency of the photomultiplier tube manufactured by the surface evaporation source evaporation device disclosed in this patent is relatively high, ranging from 31.4% to 31.7%, while the quantum efficiency of the photomultiplier tube manufactured by the conventional metal wire loaded spherical point evaporation source device The quantum efficiency of the photomultiplier tube is between 23.3% and 30.2%.

Therefore, the quantum efficiency and quantum efficiency uniformity of photomultiplier tubes manufactured using the patented surface evaporation source evaporation device are significantly better than those of photomultiplier tubes manufactured using conventional metal wire-loaded spherical point evaporation source devices.

Randomly select 20 photomultiplier tubes produced by two coating processes for appearance inspection and dark current testing. The photomultiplier tubes produced using a sheet surface evaporation device have a pass rate of 100% and an average dark current of 1.5nA. One of the photomultiplier tubes produced using a traditional spherical point evaporation source had an antimony bead falling off and falling off, with a pass rate of 95% and an average dark current of 5.3nA.

Combined with the above embodiments, the present invention proposes a sheet surface evaporation device that can flexibly adjust the shape of the sheet surface evaporation device according to the geometry of the photomultiplier tube light window, and utilizes the advantages of the surface evaporation source to improve the uniformity of its coating. Thereby improving the quantum efficiency uniformity of the device. Moreover, the coating direction of the sheet surface evaporation device only faces the glass light window, and other directions are blocked by its own evaporation source sheet. It will not evaporate to locations such as ceramics that do not require coating, which can improve the noise characteristics of the entire tube.

In addition, the evaporation material on the sheet surface evaporation device is pre- quantitatively deposited on the evaporation source sheet through magnetron sputtering or electron beam evaporation, and is in a thin film state. Therefore, when using a sheet surface evaporation device for coating, there will be no explosion problems like antimony bead coating, and the evaporation rate and film thickness are controllable and adjustable; after the coating is completed, the evaporation material on the sheet is almost All will be evaporated, so there will be no problem of evaporated materials falling to form foreign matter or causing short circuit between electrodes, ensuring that the device has good impact and vibration resistance.

Although the present invention has been disclosed above in terms of preferred embodiments, these are not intended to limit the present invention. Those with ordinary skill in the technical field to which the present invention belongs can make various modifications and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be determined by the claims.

Claims (13)

1. An evaporation device for plating a film on a photomultiplier tube, comprising:

an evaporation electrode including a positive electrode and a negative electrode;

an evaporation source structure (11), a first end of the evaporation source structure (11) being connected to the positive electrode, a second end of the evaporation source structure (11) being connected to the negative electrode;

an evaporation material layer (12) connected to the evaporation source structure (11);

the evaporation source structure (11) comprises an evaporation surface, the evaporation material layer (12) is connected to the evaporation surface, the evaporation surface faces the direction of the structure to be coated, and the thickness of the evaporation material layer is the same;

when the positive electrode and the negative electrode are connected to the driving circuit, the evaporation source structure (11) heats, so that the evaporation material layer (12) evaporates to form a plating layer on the surface of the structure to be plated.

2. The evaporation device for photomultiplier coating according to claim 1, characterized in that the shape of the layer of evaporation material (12) matches the shape of the structure to be coated.

3. The evaporation device for photomultiplier coating according to claim 1, characterized in that the evaporation source structure (11) is constructed in a sheet shape, which is provided with the evaporation surface, the shape of which matches the shape of the structure to be coated, and the thickness of the evaporation source structure (11) is uniform.

4. The vapor deposition device for photomultiplier tube plating film according to claim 3, wherein the evaporation source structure (11) is configured in a semicircular ring shape or a rectangular bar shape.

5. The evaporation device for photomultiplier coating film according to claim 1, wherein the evaporation source structures (11) are provided in a pair and symmetrically arranged, and two of the evaporation source structures (11) are connected in parallel to the driving circuit.

6. The evaporation device for photomultiplier coating according to claim 1, wherein the evaporation source structure (11) comprises tantalum, tungsten or platinum material.

7. The evaporation device for photomultiplier tube coating according to claim 1, wherein the evaporation material layer (12) is evaporated onto the evaporation surface of the evaporation source structure (11) by means of magnetron sputtering or electron beam evaporation.

8. The method for manufacturing an evaporation device for a photomultiplier tube plating film according to any one of claims 1 to 7, comprising the steps of:

s1, manufacturing an evaporation source structure (11):

s11, forming a metal sheet matched with the shape image of the structure to be coated according to the shape of the structure to be coated;

s2, manufacturing an evaporation material layer (12):

step S21, evaporating an evaporating material on the surface of the metal sheet in advance by a high-precision film coating method according to the thickness of a film coating process of a structure to be coated, and forming a preset thickness;

the high-precision coating method comprises magnetron sputtering or electron beam evaporation.

9. The method for manufacturing a deposition apparatus for a photomultiplier tube plating film according to claim 8, wherein in step S21, the thickness control of the evaporation material comprises the steps of:

manufacturing a vacuum environment, and filling argon;

controlling the magnetron sputtering target material to emit coating material to a preset area;

the evaporation source structure (11) passes through the sputtering area of the target material reciprocally at a preset speed;

the speed and the times of sputtering the evaporation source structure (11) through the target material are controlled, so that the thickness of the evaporation material layer (12) formed on the surface of the evaporation source structure (11) reaches the target thickness.

10. A manufacturing apparatus for an evaporation apparatus for a photomultiplier tube plating film according to any one of claims 1 to 7, comprising:

the coating machine cavity is used for constructing a coating environment;

the magnetron sputtering target is arranged in the film plating machine cavity and is used for emitting film plating materials to a sputtering area;

the track is arranged in the film plating machine cavity and passes through the sputtering area;

a tray for holding a plurality of the evaporation source structures (11), the tray being connected to a track along which the tray can reciprocate to enter or leave a sputtering region of a magnetron sputtering target;

wherein the track is arranged to drive the tray through the sputtering zone at a predetermined speed to control the length of time the evaporation source structure (11) is located in the sputtering zone.

11. The evaporation method for the photomultiplier light window coating film is characterized by comprising the following steps of:

a, manufacturing and forming a first film layer vapor deposition device and a second film layer vapor deposition device according to the manufacturing method of the vapor deposition device for plating a film of a photomultiplier according to claim 8;

b, connecting anodes of the first film evaporation device and the second film evaporation device to the first positive terminal and the second positive terminal respectively, and connecting cathodes of the first film evaporation device and the second film evaporation device to a focusing electrode of a photomultiplier;

step c, loading current to the first positive terminal and the focusing electrode of the photomultiplier to form a first film layer on the surface of the light window, and loading current to the second positive terminal and the focusing electrode of the photomultiplier to form a second film layer on the surface of the light window;

wherein, the metal target material of the first vapor deposition device comprises manganese and titanium, and the metal target material of the second vapor deposition device comprises antimony and tellurium.

12. The evaporation method for photomultiplier tube window coating according to claim 11, wherein,

when the first film evaporation device is prepared, the following process is adopted: the sputtering power of the manganese target is set to be 15-20W/cm ² The movement speed of the workpiece disc is 6mm/s, and the reciprocating times are 4-5 times;

when the second film evaporation device is prepared, the following process is adopted: the sputtering power of the antimony target is set to be 10-15W/cm ² The movement speed of the workpiece disc is 8mm/s, and the reciprocating times are 3-4 times.

13. An evaporation device for plating a film on a light window of a photomultiplier tube, comprising:

a focusing electrode of the photomultiplier;

a glass light window;

a first film vapor deposition apparatus comprising a pair of vapor deposition apparatuses for photomultiplier film plating according to any one of claims 1 to 7;

a second film vapor deposition apparatus comprising a pair of vapor deposition apparatuses for photomultiplier film plating according to any one of claims 1 to 7;

two positive terminal posts connected to the focusing electrode of the photomultiplier;

the first end of the first film evaporation device is connected to a first positive terminal through a positive lead, and the second end of the first film evaporation device is connected to a focusing electrode of the photomultiplier;

the first end of the second film evaporation device is connected to a second positive terminal through a positive lead, and the second end of the second film evaporation device is connected to a focusing electrode of the photomultiplier;

wherein, a pair of vapor deposition devices for plating films of the photomultiplier in the first film vapor deposition device are symmetrically distributed around the axis of the glass light window;

and a pair of evaporation devices for plating films of the photomultiplier in the second film evaporation device are symmetrically distributed around the axis of the glass light window.