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

Abstract

The present invention relates to the technical field of photomultiplier tube processing, and more specifically to an evaporation device for photomultiplier tube coating, a method for manufacturing the device, and an evaporation method and device for light window coating, comprising: an evaporation electrode, including a positive electrode and a negative electrode; an evaporation source structure, wherein 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; an evaporation material layer is connected to the evaporation source structure; wherein the evaporation source structure comprises an evaporation surface, and the evaporation material layer is connected to the evaporation surface. The advantages of the surface evaporation source are utilized to improve the uniformity of its coating, thereby improving the uniformity of the quantum efficiency of the device. Moreover, the coating direction of the sheet-shaped surface evaporation device is only toward the glass light window, and the other directions are blocked by its own evaporation source sheet, so that it will not evaporate to positions such as ceramics where coating is not required, thereby improving the noise characteristics of the entire tube.

Description

Technical Field

[0001] The present invention relates to the technical field of photomultiplier tube processing, and in particular to an evaporation device for photomultiplier tube coating and a manufacturing method and device thereof, as well as an evaporation method and device for optical window coating. Background Art

[0002] The film layer on the photomultiplier tube light window includes an anti-reflection film and a photocathode film. The cathode quantum efficiency is one of the key performance indicators that determine its photoelectric detection capability. The key to the production of the photomultiplier tube cathode is the coating of the optical anti-reflection film and the photoelectric emission film. The film thickness of the anti-reflection film and the photoelectric emission film largely determines the cathode quantum efficiency, so the uniformity of the film thickness of the anti-reflection film and the photoelectric emission film also determines the uniformity of the cathode quantum efficiency.

[0003] Combination Figure 1 As shown in the figure, the traditional cathode antireflection film preparation method is: a tantalum wire loaded with a metal manganese ball is used as an evaporation device, and a current is applied to the tantalum wire to heat it so that the metal ball is evaporated onto the glass window of the photomultiplier tube, and oxygen is passed through to oxidize it to obtain a metal oxide antireflection film. Similarly, the preparation of the photoelectric emission film layer uses a nickel wire or a platinum-coated molybdenum wire loaded with a metal antimony ball as an evaporation device, and a current is applied to evaporate the antimony ball onto the glass window.

[0004] The above-mentioned antireflection film and antimony film evaporation methods all use a point evaporation source as the evaporation device. This evaporation method often produces a thicker film at a location closer to the point evaporation source, so there is a large difference in film thickness uniformity. Secondly, the coating direction of the spherical evaporation source is non-selective, and often the film is plated on the ceramic sheet, glass wall, focusing electrode, etc. of the photomultiplier tube while being plated on the glass window, causing problems such as inter-electrode ohmic leakage and increased thermal electron emission noise of the device.

[0005] Furthermore, when metal balls are used as evaporation materials for coating, the evaporation rate is often uncontrollable, and metal balls often evaporate explosively or burst, resulting in uncontrollable coating thickness of antireflection film and metal antimony film. More seriously, when metal wires are used as evaporation devices, after the antimony film is evaporated, most of the metal antimony beads will often remain. In the subsequent photocathode activation process, the remaining metal antimony balls will absorb potassium, sodium, and cesium alkali metals and expand rapidly and become loose, and cannot be firmly adhered to the metal wires. When the photomultiplier tube is subjected to impact and vibration, the loose antimony balls will peel off the metal wires, forming foreign matter in the tube and causing a short circuit between the electrodes, which will cause the device to fail. Summary of the invention

[0006] The present invention proposes a technical solution in a first aspect, a vapor deposition device for photomultiplier tube coating, comprising:

[0007] Evaporation electrodes, including a positive electrode and a negative electrode;

[0008] an evaporation source structure, wherein 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;

[0009] an evaporation material layer connected to the evaporation source structure;

[0010] Wherein, the evaporation source structure comprises 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, and the thickness of the evaporation material layer is the same;

[0011] When the positive electrode and the negative electrode are connected to the driving circuit, the evaporation source structure generates heat, so that the evaporation material layer evaporates to form a coating on the surface of the structure to be coated.

[0012] Preferably, the shape of the evaporation material layer matches the shape of the structure to be coated.

[0013] Preferably, the evaporation source structure is constructed in a sheet shape, 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, and the thickness of the evaporation source structure is uniform.

[0014] Preferably, the evaporation source structure is configured in a semicircular ring shape or a right-angled bar shape.

[0015] Preferably, the evaporation source structures are provided as a pair and are arranged symmetrically, and the two evaporation source structures are connected to the driving circuit in parallel.

[0016] Preferably, the evaporation source structure comprises tantalum, tungsten or platinum material.

[0017] Preferably, the evaporation material layer is evaporated onto the evaporation surface of the evaporation source structure by magnetron sputtering or electron beam evaporation.

[0018] The second aspect of the present invention provides a technical solution, a method for manufacturing a vapor deposition device for photomultiplier tube coating, characterized in that it comprises the following steps:

[0019] S1. Making evaporation source structure:

[0020] S11, forming a metal sheet matching the shape of the structure to be coated according to the shape of the structure to be coated;

[0021] S2. Making evaporation material layer:

[0022] Step S21, according to the coating process thickness of the structure to be coated, pre-evaporating the evaporation material onto the surface of the metal sheet by a high-precision coating method to form a predetermined thickness;

[0023] Among them, high-precision coating methods include magnetron sputtering or electron beam evaporation.

[0024] Preferably, in step S21, controlling the thickness of the evaporated material includes the following steps:

[0025] Create a vacuum environment and fill it with argon gas;

[0026] Controlling the magnetron sputtering target to emit the coating material to a predetermined area;

[0027] The evaporation source structure reciprocates through the target sputtering area at a predetermined speed;

[0028] The speed and number of times of the evaporation source structure passing through the target material sputtering are controlled so that the thickness of the evaporation material layer formed on the surface of the evaporation source structure reaches the target thickness.

[0029] The third aspect of the present invention provides a technical solution, a manufacturing device for a vapor deposition device for photomultiplier tube coating, comprising:

[0030] A coating machine cavity, wherein the coating machine cavity is used to construct a coating environment;

[0031] 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;

[0032] A track, arranged in the coating machine cavity and passing through the sputtering area;

[0033] A tray, used for holding a plurality of the evaporation source structures, the tray being connected to a track, and the tray being able to reciprocate along the track to enter or leave a sputtering area of ​​a magnetron sputtering target;

[0034] The track is configured to drive the tray to pass through the sputtering area at a predetermined speed to control the time the evaporation source structure is in the sputtering area.

[0035] A fourth aspect of the present invention provides a technical solution, a vapor deposition method for photomultiplier tube optical window coating, comprising the following steps:

[0036] Step a, manufacturing a first film layer evaporation device and a second film layer evaporation device according to the above-mentioned method for manufacturing an evaporation device for photomultiplier tube coating;

[0037] Step b, connecting 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, and connecting the negative electrodes of the first film layer evaporation device and the second film layer evaporation device to the focusing electrode of the photomultiplier tube;

[0038] Step c, applying current to the first positive electrode terminal and the focusing electrode of the photomultiplier tube to form a first film layer on the surface of the light window, and then applying current to the second positive electrode terminal and the focusing electrode of the photomultiplier tube to form a second film layer on the surface of the light window;

[0039] 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.

[0040] Preferably, when preparing the first film layer evaporation device, the following process is used: the manganese target sputtering power is set to 15-20 W / cm 2 , the movement speed of the workpiece disc is 6mm / s, and the number of reciprocating times is 4~5 times;

[0041] When preparing the second film layer evaporation device, the following process is followed: 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 reciprocating times is 3~4 times.

[0042] The fifth aspect of the present invention provides a technical solution, a vapor deposition device for photomultiplier tube optical window coating, comprising:

[0043] The focusing electrode of the photomultiplier tube;

[0044] Glass light windows;

[0045] The first film layer evaporation device comprises a pair of the above-mentioned evaporation devices for photomultiplier tube coating;

[0046] The second film layer evaporation device comprises a pair of the above-mentioned evaporation devices for photomultiplier tube coating;

[0047] two positive electrode terminals connected to the focusing electrodes of the photomultiplier tube;

[0048] The first end of the first film layer evaporation device is connected to the first positive electrode terminal through a positive electrode lead, and the second end is connected to the focusing electrode of the photomultiplier tube;

[0049] The first end of the second film layer evaporation device is connected to the second positive electrode terminal through the positive electrode lead, and the second end is connected to the focusing electrode of the photomultiplier tube;

[0050] 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;

[0051] A pair of evaporation devices for photomultiplier tube coating in the second film layer evaporation device are symmetrically distributed around the axis of the glass light window.

[0052] Compared with the prior art, the advantages of the present invention are:

[0053] The present invention proposes a sheet-shaped surface evaporation device, which can flexibly adjust the shape of the sheet-shaped surface evaporation device according to the geometric shape of the photomultiplier tube light window, and use the advantages of the surface evaporation source to improve the uniformity of its coating, thereby improving the uniformity of the quantum efficiency of the device. In addition, the coating direction of the sheet-shaped surface evaporation device is only toward the glass light window, and the other directions are blocked by its own evaporation source sheet, so that it will not evaporate to the position where the coating is not required, such as ceramics, and the noise characteristics of the whole tube can be improved.

[0054] In addition, the evaporation material on the sheet surface evaporation device is pre-quantitatively deposited on the evaporation source sheet by magnetron sputtering or electron beam evaporation, and is in a thin film state. Therefore, when using the sheet surface evaporation device for coating, there will be no explosion problems similar to antimony bead coating, and its evaporation rate and film thickness are controllable and adjustable; after the coating is completed, the evaporation material on the thin sheet will be almost completely evaporated, so there will be no problem of evaporation material falling to form foreign matter or causing inter-electrode short circuit, ensuring that the device has good shock and vibration resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] The drawings are not intended to be drawn to scale. In the drawings, each identical or nearly identical component shown in various figures may be represented by the same reference numeral. For clarity, not every component is labeled in every figure. Embodiments of various aspects of the present invention will now be described by way of example and with reference to the accompanying drawings, in which:

[0056] Figure 1 It is a schematic diagram of coating a glass window using a point evaporation source as an evaporation device in the prior art;

[0057] Figure 2 is a schematic cross-sectional structural diagram of the evaporation device shown in the present invention;

[0058] Figure 3 is a schematic diagram showing that the evaporation device shown in the present invention is constructed into a double semicircular ring structure;

[0059] Figure 4 is a schematic diagram showing that the evaporation device shown in the present invention is constructed into a double right-angled bar structure;

[0060] Figure 5 is a schematic structural diagram of a manufacturing device for a vapor deposition device shown in the present invention;

[0061] Figure 6 It is a structural schematic diagram of a vapor deposition device for photomultiplier tube optical window coating shown in the present invention;

[0062] Figure 7a This is the distribution diagram of quantum efficiency of photomultiplier tube prepared by metal wire loaded spherical evaporation source device;

[0063] Figure 7bThis is a distribution diagram of the quantum efficiency of the photomultiplier tube prepared in this embodiment. DETAILED DESCRIPTION

[0064] In order to better understand the technical content of the present invention, specific embodiments are given and described as follows in conjunction with the accompanying drawings.

[0065] Combination Figure 1 As shown in the figure, the traditional cathode antireflection film preparation method is: a tantalum wire loaded with a metal manganese ball is used as an evaporation device, and a current is applied to the tantalum wire to heat it so that the metal ball is evaporated onto the glass window of the photomultiplier tube, and oxygen is passed through to oxidize it to obtain a metal oxide antireflection film. Similarly, the preparation of the photoelectric emission film layer uses a nickel wire or a platinum-coated molybdenum wire loaded with a metal antimony ball as an evaporation device, and a current is applied to evaporate the antimony ball onto the glass window.

[0066] The above-mentioned antireflection film and antimony film evaporation methods all use a point evaporation source as the evaporation device. This evaporation method often produces a thicker film at a location closer to the point evaporation source, so there is a large difference in film thickness uniformity. Secondly, the coating direction of the spherical evaporation source is non-selective, and often the film is plated on the ceramic sheet, glass wall, focusing electrode, etc. of the photomultiplier tube while being plated on the glass window, causing problems such as inter-electrode ohmic leakage and increased thermal electron emission noise of the device.

[0067] Therefore, the first aspect of the present application proposes an evaporation device for coating photomultiplier tubes, which is a sheet-shaped surface evaporation device that mainly utilizes the characteristics of a surface evaporation source to improve the coating uniformity of the structure to be coated, especially the photomultiplier tube light window, thereby improving the quantum efficiency uniformity of the photomultiplier tube.

[0068] In addition, the sheet-shaped surface evaporation device can flexibly adjust the shape of the sheet-shaped surface evaporation device according to the shape of the photomultiplier tube light window to adapt to different light window shapes, such as a circular or rectangular light window.

[0069] Secondly, the coating direction of the sheet surface evaporation device is only toward the glass light window, and the other directions are blocked by its own evaporation source sheet. It will not evaporate to the positions such as ceramics that do not need coating, which can improve the noise characteristics of the whole tube.

[0070] In addition, the evaporation material on the sheet surface evaporation device is pre-quantitatively deposited onto the evaporation source sheet by magnetron sputtering or electron beam evaporation. Therefore, when the sheet surface evaporation device is used for coating, the evaporation rate and film thickness are controllable and adjustable.

[0071] More importantly, after this sheet-shaped surface evaporation device completes the coating of the photomultiplier tube, the evaporation material will be almost completely evaporated, so there will be no problem of evaporation material falling to form foreign matter or causing inter-electrode short circuit, ensuring that the device has good impact and vibration resistance.

[0072]

Evaporation device for photomultiplier tube coating

[0073] Combination Figure 2-4 As shown, the present invention proposes a technical solution in the first aspect, a 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 a positive electrode and a 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.

[0074] Specifically, the evaporation source structure 11 is intended to provide the heat required for evaporation of the evaporation material layer 12. 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, which are made into a thin sheet with electrodes formed at both ends. When a certain current is loaded at both ends, the evaporation source structure 11 generates heat, and the heat is used to evaporate the evaporation material layer 12 attached to the surface of the evaporation source structure 11.

[0075] The evaporation source structure 11 includes 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 from the evaporation surface to the direction of the structure to be coated.

[0076] In this way, when the positive electrode and the negative electrode are connected to the driving circuit, the evaporation source structure 11 generates heat, so that the evaporation material layer 12 evaporates to form a coating on the surface of the structure to be coated.

[0077] It can be understood that this form of surface evaporation has the advantages of controllable direction and controllable evaporation amount compared to the spherical evaporation source in the prior art.

[0078] In addition, depending on the different materials to be coated, the material of the evaporation material layer 12 is different. For the light window coating, it generally includes an anti-reflection film layer and a photoelectric emission layer. Among them, the anti-reflection film layer generally uses manganese, titanium, aluminum and other materials, and the photoelectric emission layer generally uses antimony, tellurium, iodine and other materials. In this application, the evaporation device used to manufacture the anti-reflection film layer is referred to as the first film layer evaporation device, and the evaporation device used to manufacture the photoelectric emission layer is referred to as the second film layer evaporation device.

[0079] Furthermore, in order to control the evaporation material to be accurately attached 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 structure to be coated in the direction corresponding to the evaporation surface and adheres to the corresponding area of ​​the structure to be coated. In this way, the evaporation material can be accurately controlled to form a coating coverage on the surface of the structure to be coated.

[0080] Furthermore, in order to control the evaporation material layer 12 to evaporate evenly by heating, the evaporation source structure 11 is constructed in a sheet shape. The sheet-shaped evaporation source structure is provided with an evaporation surface whose shape matches the shape of the structure to be coated. The thickness of the evaporation source structure 11 is uniform.

[0081] 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 evaporated uniformly.

[0082] In an optional embodiment, for a circular or spherical light window of a photomultiplier tube, the evaporation source structure 11 and the evaporation material layer 12 on its surface are in the shape of a double semicircular ring, such as Figure 3 As shown in the figure, for the square window coating of the photomultiplier tube, the evaporation source structure 11 and the evaporation material layer 12 on its surface are in the shape of right-angled strips, such as Figure 4 shown.

[0083] Figure 3 The figure shows a pair of semicircular first film layer evaporation devices 100a and 100b, with a positive electrode 101 and a negative electrode 102 formed at two ends thereof, respectively. Figure 4 Shown is a pair of right-angled bar-shaped first film layer evaporation devices 200a and 200b, with a positive electrode 201 and a negative electrode 202 formed at two ends thereof respectively.

[0084] Preferably, the evaporation source structures 11 are provided in a pair and arranged symmetrically, and the two evaporation source structures 11 are connected in parallel to the driving circuit.

[0085] In this way, the heat of the two evaporation source structures 11 can be made consistent, and the evaporation material layer 12 can be evaporated efficiently onto the surface of the light window to form a coating.

[0086] 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 onto the evaporation surface of the evaporation source structure 11 by magnetron sputtering or electron beam evaporation.

[0087] In this way, the evaporation material layer 12 is pre-quantitatively deposited on the evaporation source structure 11 by magnetron sputtering or electron beam evaporation, and is in a thin film state. Therefore, when using a sheet-shaped surface evaporation device for coating, there will be no explosion problem similar to antimony bead coating, and the evaporation rate and film thickness are controllable and adjustable. After the coating is completed, the evaporation material on the thin sheet will be almost completely evaporated, so there will be no problem of evaporation material falling to form foreign matter or causing inter-electrode short circuit, ensuring that the device has good shock and vibration resistance.

[0088] [Method for manufacturing a vapor deposition device for photomultiplier tube coating]

[0089] The second aspect of the present invention provides a technical solution, a method for manufacturing a vapor deposition device for photomultiplier tube coating, characterized in that it comprises the following steps:

[0090] S1. Making an evaporation source structure 11:

[0091] S11, forming a metal sheet matching the shape of the structure to be coated according to the shape of the structure to be coated;

[0092] S2, making evaporation material layer 12:

[0093] Step S21, according to the coating process thickness of the structure to be coated, pre-evaporating the evaporation material onto the surface of the metal sheet by a high-precision coating method to form a predetermined thickness;

[0094] Among them, high-precision coating methods include magnetron sputtering or electron beam evaporation.

[0095] It can be understood that according to the shape of the structure to be coated (such as window glass), a thin film structure of a corresponding shape is made using a high melting point metal (tantalum, tungsten, platinum, etc.), and then multiple thin films are placed together on a tray, and the tray as a whole is passed through the evaporation area of ​​magnetron sputtering or electron beam evaporation.

[0096] Magnetron sputtering or electron beam evaporation are both means of high-precision coating. In this way, the thickness of the evaporation material layer 12 on the evaporation source structure 11 can be accurately controlled to ensure that after the evaporation is completed, there will be no problem of evaporation material falling to form foreign matter or causing inter-electrode short circuit, ensuring that the device has good impact and vibration resistance.

[0097] Preferably, in step S21, controlling the thickness of the evaporated material includes the following steps:

[0098] Create a vacuum environment and fill it with argon gas, which provides an Ar ion source;

[0099] Controlling the magnetron sputtering target to emit the coating material to a predetermined area;

[0100] The evaporation source structure 11 reciprocates through the target sputtering area at a predetermined speed;

[0101] The speed and number of times that the evaporation source structure 11 passes through the target material sputtering 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.

[0102] Specific, combined Figure 5As shown, the sheet 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. The vacuum acquisition system of the coating machine is started, and the vacuum is pre-evacuated to a vacuum degree better than 1E-3Pa. Ar is injected to maintain the vacuum in the coating machine chamber at 0.2 Pa~0.8 Pa. The movement speed of the workpiece tray is set to 6~18mm / s, and the workpiece tray moves along the slide rail to the bottom of the target material 300 for reciprocating sputtering coating, thereby coating a layer of thin film evaporation material on the surface of the sheet evaporation source 100.

[0103] It can be understood that, under the same sputtering power, the faster the movement speed of the workpiece disk is, the thinner the coating layer is.

[0104] Therefore, the coating thickness can be precisely controlled by adjusting the movement speed of the workpiece disk and the number of reciprocating movements of the workpiece disk. Optionally, the coating thickness is generally 50nm~300nm.

[0105]

Equipment for manufacturing evaporation device for photomultiplier tube coating

[0106] Combination Figure 5 As shown, the third aspect of the present invention proposes a technical solution, a manufacturing device for a vapor deposition device for photomultiplier tube coating, comprising:

[0107] The coating machine cavity 600 is used to construct a coating environment, such as a vacuum degree of 0.2 Pa to 0.8 Pa;

[0108] A magnetron sputtering target 300 is disposed in a coating machine chamber 600, and the magnetron sputtering target 300 is used to emit coating material to a sputtering area;

[0109] A track 500 is disposed in a coating machine chamber 600 and passes through a sputtering area;

[0110] A tray 400 is used to hold a plurality of sheet evaporation sources 100. The tray 400 is connected to a track 500. The tray 400 can reciprocate along the track 500 to enter or leave the sputtering area of ​​the magnetron sputtering target.

[0111] The track 500 is configured to drive the tray 400 to pass through the sputtering area at a predetermined speed to control the time that the evaporation source structure 11 is in the sputtering area.

[0112] In a specific embodiment, a semicircular sheet-shaped evaporation device is manufactured for use in coating circular light windows, wherein a first film layer evaporation device 100a and a second film layer evaporation device 100c need to be manufactured.

[0113] The semicircular ring-shaped sheet surface evaporation device is made by magnetron sputtering. The preparation process is as follows:

[0114] Lay the sheet evaporation source 100 to be coated on the workpiece tray 400, and install the workpiece tray 400 on the slide rail 500 of the coating machine. Start the vacuum acquisition system of the coating machine and pre-evacuate to a vacuum degree better than 1E-3 Pa. Inject Ar to maintain the vacuum in the coating machine chamber at 0.2 Pa~0.8 Pa. Set the movement speed of the workpiece tray to 6~18mm / s, and move the workpiece tray along the slide rail to the bottom of the target material 300 for reciprocating sputtering coating, so as to coat a layer of thin film evaporation material on the surface of the sheet evaporation source 100.

[0115] Optional, the coating thickness is generally 50nm~300nm.

[0116] (a) Preparation of sheet-shaped surface evaporation device for antireflection film preparation

[0117] When manufacturing a sheet-shaped surface evaporation device for preparing an antireflection film, the magnetron sputtering target 300 is made of a metal target such as manganese or titanium. Taking a manganese target as an example, the sputtering power is set to 15-20 W / cm 2 Set the workpiece disk's movement speed to 6mm / s and the number of reciprocating times to 4 to 5 times.

[0118] (b) Preparation of a sheet-shaped surface evaporation device for the cathode photoemission layer

[0119] When manufacturing a sheet-shaped surface evaporation device for preparing a cathode photoelectric emission layer, the magnetron sputtering target 300 is made of antimony, tellurium and other target materials. Taking the antimony target as an example, the sputtering power is set to 10~15W / cm 2 Set the movement speed of the workpiece disk to 8mm / s and the number of reciprocating times to 3~4 times.

[0120] [Evaporation method for photomultiplier tube optical window coating]

[0121] A fourth aspect of the present invention provides a technical solution, a vapor deposition method for photomultiplier tube optical window coating, comprising the following steps:

[0122] Step a, manufacturing a first film layer evaporation device and a second film layer evaporation device according to the above-mentioned method for manufacturing an evaporation device for photomultiplier tube coating;

[0123] Step b, connecting 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, and connecting the negative electrodes of the first film layer evaporation device and the second film layer evaporation device to the focusing electrode of the photomultiplier tube;

[0124] Step c, applying current to the first positive electrode terminal and the focusing electrode of the photomultiplier tube to form a first film layer on the surface of the light window, and then applying current to the second positive electrode terminal and the focusing electrode of the photomultiplier tube to form a second film layer on the surface of the light window;

[0125] The metal target material of the first evaporation device includes manganese, titanium, etc., and the metal target material of the second evaporation device includes antimony, tellurium, etc.

[0126] Optionally, when preparing the first film layer evaporation device, the following process is used: the manganese target sputtering power is set to 15-20 W / cm 2 , the movement speed of the workpiece disc is 6mm / s, and the number of reciprocating times is 4~5 times;

[0127] When preparing the second film layer evaporation device, the following process is followed: 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 reciprocating times is 3~4 times.

[0128] [Evaporation device for photomultiplier tube optical window coating]

[0129] Combination Figure 6 As shown, the fifth aspect of the present invention proposes a technical solution, a vapor deposition device for coating a light window of a photomultiplier tube, comprising a first film layer vapor deposition device 100a, a second film layer vapor deposition device 100c, a focusing electrode 700 of a photomultiplier tube, a glass light window 800, a positive electrode lead 900, and a positive electrode terminal 901. The first film layer vapor deposition device 100a is used to vapor-deposit an antireflection film on the inner surface of the glass light window 800, and the second film layer vapor deposition device 100c is used to vapor-deposit a metal antimony film on the inner surface of the glass light window 800.

[0130] Combination Figure 6 As shown, the first film layer evaporation device 100a and the second film layer evaporation device 100c are arranged to be nested with each other, and are located on the inner side or the outer side of each other, which can ensure the uniformity of the two layers of coating. In addition, 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, so that it can be ensured that after the two evaporation source structures 11 are powered on, the evaporation material layer 12 on the surface thereof is uniformly evaporated to the predetermined area of ​​the glass light window 800, so that the formed coating is uniform and the coating range falls within the predetermined range.

[0131] The assembly and deposition process of the deposition device are explained in detail using the antireflection film deposition device.

[0132] 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 through the positive electrode lead 900 tantalum wire, and is led out to the outside of the photomultiplier tube through the lead. The other end of the first film layer 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 layer evaporation device 100a.

[0133] A certain current is loaded through the positive electrode terminal 901 and the focusing electrode 700 of the photomultiplier tube, and the first film layer evaporation device 100a is heated by the electrothermal effect so as to evaporate the evaporation material on the surface onto the glass window 800 to form the first film layer, namely the anti-reflection film.

[0134] The coating structure and principle of the second film layer metal antimony film 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 anti-reflection film evaporation through the positive electrode lead 900 tantalum wire, and is led out to the outside of the photomultiplier tube through the lead wire. The other end of the second film layer 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 layer evaporation device 100c.

[0135] A certain current is loaded through the positive electrode terminal 901 and the focusing electrode 700 of the photomultiplier tube, and the second film layer evaporation device 100c is heated by the electrothermal effect to evaporate the evaporation material on the surface onto the glass window 800 to form a second film layer, namely a metal antimony film.

[0136] Further, the coating and cathode activation comprises the following steps:

[0137] 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. Manganese is first evaporated according to the photomultiplier tube manufacturing process, the evaporation current is set to 5~10A, and the size is evaporated for 1~2min; then oxygen is flushed into the photomultiplier tube to oxidize manganese into a manganese oxide antireflection film.

[0138] After the antireflection film is prepared, the vacuum degree in the photomultiplier tube is evacuated to below 1E-4Pa, and then antimony and alkali metal activation are performed. The antimony evaporation current is 2~4A, and the evaporation lasts for 2~5min, and then alkali metal K and Cs are activated in turn.

[0139] Furthermore, the cathode quantum efficiency of 16 points on the cathode surface of the photomultiplier tube manufactured by different evaporation devices was measured. Figure 7a This is a distribution diagram of the quantum efficiency of the photomultiplier tube of the surface evaporation device using the solution disclosed in this embodiment. Figure 7b This is the quantum efficiency distribution diagram of the photomultiplier tube prepared using a traditional conventional metal wire-loaded spherical evaporation source device.

[0140] It can be seen that the quantum efficiency of each point of the photomultiplier tube manufactured by the surface evaporation source evaporation device using the solution disclosed in this patent is relatively high, both ranging from 31.4% to 31.7%, while the quantum efficiency of the photomultiplier tube made by the conventional metal wire-loaded spherical point evaporation source device is between 23.3% and 30.2%.

[0141] Therefore, the quantum efficiency and quantum efficiency uniformity of the photomultiplier tube manufactured using the surface evaporation source evaporation device of this patent are significantly better than the performance of the photomultiplier tube manufactured using the conventional metal wire-loaded spherical point evaporation source device.

[0142] 20 PMTs made by two coating processes were randomly selected for appearance inspection and dark current test. The qualified rate of PMTs made by sheet surface evaporation device was 100%, and the average dark current was 1.5nA. Among the PMTs made by traditional spherical point evaporation source, one had antimony beads falling off and slag falling off, and the qualified rate was 95%, and the average dark current was 5.3nA.

[0143] In combination with the above embodiments, the present invention proposes a sheet-shaped surface evaporation device, which can flexibly adjust the shape of the sheet-shaped surface evaporation device according to the geometric shape of the photomultiplier tube light window, and use the advantages of the surface evaporation source to improve the uniformity of its coating, thereby improving the uniformity of the quantum efficiency of the device. In addition, the coating direction of the sheet-shaped surface evaporation device is only toward the glass light window, and the other directions are blocked by its own evaporation source sheet, so that it will not evaporate to the position where the coating is not required, such as ceramics, which can improve the noise characteristics of the whole tube.

[0144] In addition, the evaporation material on the sheet surface evaporation device is pre-quantitatively deposited on the evaporation source sheet by magnetron sputtering or electron beam evaporation, and is in a thin film state. Therefore, when using the sheet surface evaporation device for coating, there will be no explosion problems similar to antimony bead coating, and its evaporation rate and film thickness are controllable and adjustable; after the coating is completed, the evaporation material on the thin sheet will be almost completely evaporated, so there will be no problem of evaporation material falling to form foreign matter or causing inter-electrode short circuit, ensuring that the device has good shock and vibration resistance.

[0145] Although the present invention has been disclosed as above with preferred embodiments, it is not intended to limit the present invention. A person with ordinary knowledge in the technical field to which the present invention belongs may make various changes 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 definition of the claims.

Claims

1. A vapor deposition device for photomultiplier tube coating, characterized in that: include: Evaporation electrodes, including a positive electrode and a negative electrode; an evaporation source structure (11), wherein a first end of the evaporation source structure (11) is connected to the positive electrode, and a second end of the evaporation source structure (11) is 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 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 a driving circuit, the evaporation source structure (11) generates heat, causing the evaporation material layer (12) to evaporate and form a coating on the surface of the structure to be coated; The evaporation source structure (11) is constructed in a sheet shape, 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, and the thickness of the evaporation source structure (11) is uniform; The evaporation source structure (11) comprises tantalum, tungsten or platinum material; The evaporation material layer (12) comprises manganese, titanium, aluminum, antimony, tellurium or iodine material; The evaporation material layer (12) is quantitatively evaporated onto the evaporation surface of the evaporation source structure (11) by means of magnetron sputtering or electron beam evaporation, so that after the coating is completed, the evaporation material layer (12) on the evaporation source structure (11) is almost completely evaporated.

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

3. The evaporation device for photomultiplier tube coating according to claim 1, characterized in that: The evaporation source structure (11) is constructed in a semicircular ring shape or a right-angled strip shape.

4. The evaporation device for photomultiplier tube coating according to claim 1, characterized in that: The evaporation source structures (11) are arranged in a pair and symmetrically, and the two evaporation source structures (11) are connected in parallel to the drive circuit.

5. The method for manufacturing a vapor deposition device for photomultiplier tube coating according to any one of claims 1 to 4, characterized in that: The following steps are involved: S1. Fabrication of evaporation source structure (11): S11, forming a metal sheet matching the shape of the structure to be coated according to the shape of the structure to be coated; S2. Making an evaporation material layer (12): Step S21, according to the coating process thickness of the structure to be coated, pre-evaporating the evaporation material onto the surface of the metal sheet by a high-precision coating method to form a predetermined thickness; Among them, high-precision coating methods include magnetron sputtering or electron beam evaporation.

6. The method for manufacturing a vapor deposition device for photomultiplier tube coating according to claim 5, characterized in that: In step S21, controlling the thickness of the evaporated material includes the following steps: Create a vacuum environment and fill it with argon gas; Controlling the magnetron sputtering target to emit the coating material to a predetermined area; The evaporation source structure (11) reciprocates through the target sputtering area at a predetermined speed; The speed and number of times that the evaporation source structure (11) passes through the target material sputtering are 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.

7. A manufacturing device for the evaporation device for photomultiplier tube coating as claimed in any one of claims 1 to 6, characterized in that: include: A coating machine cavity, wherein 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, arranged in the coating machine cavity and passing through the sputtering area; A tray, used for holding a plurality of the evaporation source structures (11), the tray being connected to a track, and the tray being able to reciprocate along the track to enter or leave a sputtering area of ​​a magnetron sputtering target; The track is configured to drive the tray to pass through the sputtering area at a predetermined speed, so as to control the time the evaporation source structure (11) is in the sputtering area.

8. A vapor deposition method for photomultiplier tube optical window coating, characterized in that: The following steps are involved: Step a, manufacturing a first film layer evaporation device and a second film layer evaporation device according to the manufacturing method of the evaporation device for photomultiplier tube coating according to claim 7; Step b, connecting 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, and connecting the negative electrodes of the first film layer evaporation device and the second film layer evaporation device to the focusing electrode of the photomultiplier tube; Step c, applying current to the first positive electrode terminal and the focusing electrode of the photomultiplier tube to form a first film layer on the surface of the light window, and then applying current to the second positive electrode terminal and the focusing electrode of the photomultiplier tube to form a second film layer on the surface of the light window; 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.

9. The evaporation method for photomultiplier tube optical window coating according to claim 8, characterized in that: When preparing the first film layer evaporation device, the following process is followed: the manganese target sputtering power is set to 15~20 W / cm 2 , the movement speed of the workpiece disc is 6mm / s, and the number of reciprocating times is 4~5 times; When preparing the second film layer evaporation device, the following process is followed: 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 reciprocating times is 3~4 times.

10. An evaporation device for coating a photomultiplier tube optical window, characterized in that: include: The focusing pole of the photomultiplier tube; Glass light windows; The first film layer evaporation device comprises a pair of evaporation devices for photomultiplier tube coating according to any one of claims 1 to 4; The second film layer evaporation device comprises a pair of evaporation devices for photomultiplier tube coating according to any one of claims 1 to 4; two positive electrode terminals connected to the focusing electrodes of the photomultiplier tube; The first end of the first film layer evaporation device is connected to the first positive electrode terminal through a positive electrode 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 electrode terminal through the positive electrode 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; A pair of evaporation devices for photomultiplier tube coating in the second film layer evaporation device are symmetrically distributed around the axis of the glass light window.

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