77results about "Multiplier dynodes" patented technology

The invention discloses a dynamic multi-stage serial connection coaxial butterfly-type channel dynode electron multiplier. The dynamic multi-stage serial connection coaxial butterfly-type channel dynode electron multiplier comprises a plurality of stages of butterfly-type dynodes sequentially distributed from inside to outside, an emission source, a voltage source and a drive device used for driving the multiple stages of butterfly-type dynodes to rotate, wherein the multiple stages of butterfly-type dynodes are sequentially arranged along a reflection path of electrons; each stage of butterfly-type dynode comprises a negative plate, a gate electrode and an arc support; the gate electrodes are of an annular structure; the cross section of each negative plate is of an arc structure; the circle centers of the negative plate in the multiple stages of butterfly-type dynodes coincide with a rotary shaft; the inner side faces of the negative plates are covered with reflection films; the negative plates are fixed on the arc surfaces of the corresponding arc supports; the gate electrodes are fixed on the lateral faces of the corresponding arc supports; one of each gate electrode is fixedly connected with one end of the corresponding negative plate; the voltage source comprises a power source and multiple resistors connected with the power source in series. The dynamic multi-stage serial connection coaxial butterfly-type channel dynode electron multiplier is long in service life, the actual use area of the negative plates is large, and the effective electron emissivity is high.

Every time a target sample is injected from an injector (12) of an LC unit (1) and a mass spectrometry for a target component in the sample is performed, a CD voltage applied to a conversion dynode of an ion detector (29) is switched. For each of the multiple CD-voltage levels, a data collector (32) collects noise data during a period of time where no component is present and intensity data of an ion originating from the target component, while the SN ratio calculator (33) calculates an SN ratio. After the actual measurement is completed, an optimum CD voltage determiner (34) compares the SN ratios calculated for each CD voltage, finds the CD voltage which gives the highest SN ratio, and stores this voltage in an optimum CD voltage memory (42) as an optimum CD voltage for the analysis conditions at that point in time and for the m/z of the analysis target. According to this method, even when the flow rate of the mobile phase is particularly high or when a hard-to-vaporize mobile phase is used, the CD voltage is appropriately set and a detection signal is obtained with high SN ratios.

The invention discloses an automatic expansion focusing electrode and an automatic expansion focusing electrode-based photomultiplier. The photomultiplier comprises a high-vacuum seal shell, the automatic expansion focusing electrode, a high-quantum efficiency photocathode, an electronic multiplier system and a connection and lead system, wherein the high-vacuum seal shell has main functions of sealing and being used as a substrate for other films as a photomultiplier housing part; and the automatic expansion focusing electrode comprises a bottom plate, expansion blades and an automatic trigger mechanism as an electronic collector of the photomultiplier. The high-quantum efficiency photocathode is located in an upper area of the high-vacuum seal shell and converts incident photons into electrons. The electronic multiplier system is located at the lower part of the automatic expansion focusing electrode, amplifies the electrons collected by the focusing electrode and then leads out the electrons through the lead system. The automatic expansion focusing electrode touches the trigger mechanism in a photomultiplier packaging process, so that an expansion action of the automatic expansion focusing electrode is achieved and expansion of the radial size of the focusing electrode is achieved.

The invention discloses a large-area photomultiplier with a hybrid multiplication system. The large-area photomultiplier comprises a vacuum glass container, a photocathode, the electron multiplicationsystem, an anode and a power supply electrode. The photocathode, the electron multiplication system and the anode are arranged in the vacuum glass container, the anode penetrates through the vacuum glass container through a signal lead and is connected with an external circuit, and the power supply electrode penetrates through the vacuum glass container through a power line and is connected withan external power supply circuit. The photocathode covers a whole inner surface of the vacuum glass container except a handle port. The multiplication system is arranged at an internal handle port ofthe vacuum glass container, comprises a first-stage spherical dynode and a second-stage micro-channel plate component, and can receive photoelectrons generated by the photocathode in all directions and generate multiplication electrons. The photomultiplier has advantages of a large photocathode coverage area and high photoelectron collection efficiency.

The invention discloses an automatic expansion focusing electrode for a photomultiplier tube and a photomultiplier tube, wherein the automatic expansion focusing electrode comprises an expansion support rod, a metal cloth, a fixing mechanism, a rotating shaft and a touch spring. The expansion support rod, the rotating shaft and the touch spring piece are one-to-one corresponded, and are arranged around the fixing mechanism; A plurality of expansion struts rotatably mounted along an edge of the fixing mechanism and about the rotational axis; The metal cloth is arranged around the central axis of the fixing mechanism in an initial state of wrinkle folding, and each expansion rod is fixedly connected with the wrinkle edge position of the metal cloth, so that the metal cloth can be unfolded with the movement of the expansion rod to enter an expanded state. The automatic expansion focusing pole of the invention can realize the expansion action of the automatic expansion focusing pole and realize the expansion of the radial dimension of the focusing pole.

The invention provides a method for adaptively expanding the dynamic range of a photomultiplier in order to solve the problem that the dynamic range of an existing universal photomultiplier is limiteddue to the fact that the total number of electrons is too large in the electron multiplication and transmission process. The number of electrons entering the electron multiplication system is adaptively adjusted according to the intensity of the detection light, so that the electron multiplication system is in a linear output working state, the dynamic range of the photomultiplier for the intensity of the detection light is expanded, and the range can be increased by more than 10 times of the original numerical value.

The invention relates to a non-contact object surface charge photomultiplier tube amplifier, belonging to the technical field of signal detection. The principle is as follows: the intensity of incident light is determined by the number of photons passing through a unit vertical area in unit time, and if the number of photons passing through a metal surface in unit time increases, the number of times that photons collide with the electrons in the metal increases, the number of photons escaping from the metal surface in unit time increases, and the photocurrent increases; and if the intensity of incident light remains unchanged and the number of times that photons collide with the electrons in the metal increases due to increase in the number of charges on the metal surface, the number of photoelectrons escaping from the metal surface in unit time increases. The number of photoelectrons is multiplied constantly by a photomultiplier tube, and the number of electrons collected by the anode finally can be increased 104-108 times. Because of high sensitivity and low noise of the photomultiplier tube, weak charge signals on the surface of a sample can be detected. The non-contact object surface charge photomultiplier tube amplifier can be widely used in the field of charge detection.

The invention relates to a novel silver-magnesium alloy dynode and a preparation method thereof, which belong to the technical field of photomultipliers and photoelectric device dynodes. The surface layer of the dynode is a magnesium nitride film layer, and the core layer is a magnesium oxide film layer. The secondary emission coefficient is 5 to 6 (150V), which is more than 20% higher than that of the existing magnesium oxide type silver-magnesium alloy dynode. The sensitivity and the gains of the tube can be significantly improved, the service life is prolonged and the yield of products is increased, and miniaturization and portability of the tube and the assembly are also facilitated. The core magnesium oxide film is formed by oxidation of the silver-magnesium alloy base layer, the surface magnesium nitride film is formed by nitridation of the silver-magnesium alloy, an extra-tube high-temperature activation process of the conventional magnesium oxide type silver-magnesium alloy dynode is saved in the process, the production cost is reduced, and the influences on the dynode by exposed air are completely eliminated. The novel silver-magnesium alloy dynode can be used in a photomultiplier tube electron multiplier and used as a multiplier in a optoelectronic device.

An apparatus for generating and focusing electrons is provided. The apparatus has an emissive material configured to emit an electron, an electron target, and an electrical potential gradient generator configured to generate an electrical potential gradient within the emissive material. The electrical potential gradient is oriented so as to vary from positive to negative in the general direction toward the electron target. In operation, an electron emitted from the emissive materials is deflected away from the emissive material and generally toward the electron target. The apparatus may be incorporated in scientific analytical equipment such as an electron multiplier.

The invention provides a method for preparing a functional film layer on the inner wall of a channel of a microchannel plate with ultra-large length-diameter ratio. The method is characterized in thata novel designed reaction cavity for deposition is provided, a sufficient diffusion process is combined, the charge storage capacity of the microchannel plate is improved while the single functionalfilm layer or the composite functional film layer with high secondary electron emission yield, high dielectric constant and uniform thickness is deposited on the inner wall of a substrate of the microchannel plate with the ultra-large length-diameter ratio to improve the gain performance of the microchannel plate, and thereby improving the dynamic range of the microchannel plate in the applicationof a transient electron imaging and detection system.

A photomultiplier according to an embodiment of the present invention has a sealed container the interior of which is maintained in a vacuum state, and an electron multiplier unit housed in the sealed container, and the sealed container is partly constructed of ceramic side tubes, on the assumption that the photomultiplier is used under high-temperature, high-pressure environments. The photomultiplier further has a structure for fixing an installation position of the electron multiplier unit relative to the sealed container, for improvement in anti-vibration performance.