一种高性能多碱阴极侧窗型光电倍增管

Abstract

本实用新型涉及一种高性能多碱阴极侧窗型光电倍增管，属于光电倍增管技术领域。该高性能多碱阴极侧窗型光电倍增管，采用Na2KSb(Cs)合金作为阴极的光电转换材料和倍增系统的二次电子发射材料，高透紫合成石英玻璃作为玻壳主体材料兼作光线入射窗口材料，高纯镍金属片作为阴极和倍增极基底材料，高纯铝膜作为电子阻挡层材料，高纯铬膜作为陶瓷定位片的电子反射层材料。本实用新型产品的设计光谱响应范围为160～900nm，增益倍数达到1×107，阳极暗电流小于3nA。该产品可作为检测器用于原子吸收和紫外‑可见分光光度计等科学分析仪器，因其宽光谱响应范围、高增益倍数和低暗电流特点而拓展仪器的检测对象范围和应用领域。

Claims

1. A high performance multi-alkali photocathode side-on photomultiplier tube, characterized in that, Na2KSb(Cs) alloy is used as the photoelectric conversion material of the cathode and the secondary electron emission material of the multiplication system. High-transmittance ultraviolet synthetic quartz glass is used as the main material of the glass shell and also as the light incident window material. High-purity nickel metal sheet is used as the cathode and multiplication electrode substrate material. High-purity aluminum film is used as the electron blocking layer material and high-purity chromium film is used as the electron reflective layer material of the ceramic positioning sheet.

2. The high performance multialkali photocathode side-on photomultiplier tube of claim 1, wherein, It employs a side-light incident method and operates at 1000V, using a ring-shaped focusing multiplier system composed of 9 electrodes.

3. The high performance multialkali photocathode side-on photomultiplier tube of claim 2, wherein, The device mainly comprises a glass shell, a core column, a cathode, a dynode, an anode, a grid, a ceramic positioning plate, and a tube base. The glass shell and core column are connected to form an integral tube shell. The cathode, dynode, anode, and grid are fixed in position by inserting nickel rods at both ends into positioning holes on the ceramic positioning plate. One end of the cathode, dynode, anode, and grid is connected to the inner end of the core column's lead-out electrode via electrode leads. The outer end of the core column's lead-out electrode is then connected to a pin on the tube base. The main material of the glass shell is high-transmittance ultraviolet synthetic quartz glass. The substrate material of the cathode and dynode is a high-purity nickel metal sheet. An electron blocking layer, made of high-purity aluminum, is set on the arc-shaped inner surface of the cathode and dynode substrate. A photoelectric conversion functional film layer is set on the electron blocking layer of the cathode, and a secondary electron emission functional film layer is set on the electron blocking layer of the dynode. The photoelectric conversion functional film layer and the secondary electron emission functional film layer are made of Na2KSb(Cs) alloy. An electron reflective layer, made of high-purity chromium, is set on the surface of the ceramic positioning plate.

4. The high performance multialkali photocathode side-on photomultiplier tube of claim 3, wherein, The glass shell is a hollow tubular structure with one end sealed in an arc shape. The outer diameter of the tube is 28±0.3mm, and the wall thickness is 0.67±0.3mm. It is made of high-transmittance ultraviolet synthetic quartz glass with a light transmittance ≥90%@193nm and a coefficient of thermal expansion of 5.5×10⁻⁶. -7 / ℃, after six different expansion coefficients of 6, 14, 22, 30, 38, and 46×10 -7 The quartz-borosilicate glass modulator at / ℃ transitions to an expansion coefficient of 49×10. -7 It is made of B40 glass, and the part of the glass shell opposite the photocathode also serves as the light entrance window.

5. The high performance multialkali photocathode side-on photomultiplier tube of claim 3, wherein, The outer diameter of the core post is It is 1.2–1.5 mm thick, made of B40 glass, and surrounds the center along… Ten Kovar alloy lead-out electrodes with a diameter of 0.6±0.2mm are evenly distributed around the circumference; after the glass shell is inserted into the core, it is connected to the edge of the core column in an arc transition to form an integral whole.

6. The high performance multialkali photocathode side-on photomultiplier tube of claim 3, wherein, The substrate material for the cathode and dynode is a nickel sheet with a certain curvature. Two nickel rods are rolled on the axial edge of the nickel sheet for insertion and positioning. The inner surface of the nickel sheet is plated with a metal aluminum film with a thickness of 150-350nm as an electron blocking layer.

7. The high performance multialkali photocathode side-on photomultiplier tube of claim 3, wherein, A photoelectric conversion functional film layer with a thickness of 350-650 nm is prepared on the electron blocking layer of the cathode, and a secondary electron emission functional film layer with a thickness of 150-350 nm is prepared on the electron blocking layer of the dynode, both of which are made of Na2KSb(Cs).

8. The high performance multialkali photocathode side-on photomultiplier tube of claim 3, wherein, The ring-shaped focusing multiplication system includes nine multiplication poles, each consisting of two nickel rods and an arc-shaped nickel metal sheet fixed between them. The nickel rods are combined into a cage-like structure by inserting the two ends of the nickel rods into positioning holes at specific positions on the ceramic positioning sheet.

9. The high-performance multialkali photocathode side-window type photomultiplier tube according to claim 8, characterized by, After the cathode receives light, the photoelectrons emitted first move to the surface of the first dynode, and the excited secondary electrons then move along a certain path to the next dynode to excite more secondary electrons. This process is repeated until the secondary electrons emitted by the last dynode are captured by the anode to form an anode current output, thereby realizing the multiplication and amplification process of the electrical signal.

10. The high performance multialkali photocathode side-on photomultiplier tube of claim 3, wherein, The anode is a nickel rod; the ceramic positioning plate is an insulating support and assembly positioning part. The ceramic positioning plate has a series of positioning holes and a chromium metal film with a thickness of 150-350nm is plated on the surface in a certain pattern as an electron reflective layer.

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