237 results about "Electron multiplier" patented technology

An improved electron multiplier bias network that limits the response of the multiplier when the multiplier is faced with very large input signals, but then permits the multiplier to recover quickly following the large input signal. In one aspect, this invention provides an electron multiplier, having a cathode that emits electrons in response to receiving a particle, wherein the particle is one of a charged particle, a neutral particle, or a photon; an ordered chain of dynodes wherein each dynode receives electrons from a preceding dynode and emits a larger number of electrons to be received by the next dynode in the chain, wherein the first dynode of the ordered chain of dynodes receives electrons emitted by the cathode; an anode that collects the electrons emitted by the last dynode of the ordered chain of dynodes; a biasing system that biases each dynode of the ordered chain of dynodes to a specific potential; a set of charge reservoirs, wherein each charge reservoir of the set of charge reservoirs is connected with one of the dynodes of the ordered chain of dynodes; and an isolating element placed between one of the dynodes and its corresponding charge reservoir, where the isolating element is configured to control the response of the electron multiplier when the multiplier receives a large input signal, so as to permit the multiplier to enter into and exit from saturation in a controlled and rapid manner.

The present invention relates to an electron multiplier including a structure which effectively prevents an electric field from leaking to the front side of an MCP due to a voltage applied to the MCP, facilitates an operation of attaching/detaching the MCP, and prevents the MCP from being damaged and so forth during the operation. The electron multiplier includes an MCP as electron multiplying means, and an outer electric field shield member for accommodating the MCP. The electric field shield cap includes a body portion surrounding at least a side face of the MCP. The electron multiplier further includes a structure by which, while the MCP is held by the outer electric field shield member and an inner electric field shield member accommodated in the outer electric field shield member, the outer electric field shield member is attached to a base of the electron multiplier so as to facilitate the operation of attaching/detaching the MCP.

A base material assisting laser desorption-particle beam collision dissociation time-of-flight mass spectrometer relates to a mass spectrograph and provides a time-of-flight mass spectrometer obviously decreasing noise disturbance and improving mass resolution. The invention is provided with a cavity, a sample introduction probe rod, a preposition and a postposition mesh units, a particle beam generator, a multi-polar rod, a particle beam detector, a microchannel plate electron multiplier, a laser and a focusing lens. The sample introduction probe rod, the preposition mesh unit, the postposition mesh unit, the particle beam generator, the multi-polar rod, the particle beam detector, the microchannel electron multiplier are arranged inside the cavity in turn. The cavity and the sample introduction probe rod are coaxial. The axle wire of the postposition mesh unit is coaxial with the particle beam generator, the multi-polar rod and the particle beam detector. The cavity is provided with a quartz window for laser in, a vacuum opening for extraction and a valve for sample introduction probe rod in and out on the wall. The sample introduction probe rod is provided with a sampling fixing component on the top end. The laser and the focusing lens are arranged outside the cavity.

The invention belongs to the field of application of near-infrared laser, nuclear irradiation, electron and image rebuild in systematic biology and medicine. It is characterized in that high-specificity nuclear species and fluorescent probe are implanted in live animal to realize double mark of muscle deep layer or internal organ tumor cell. The emission signal of nuclear species is checked by sensitive electron-multiplier phototube in array copulation position of scintillation crystal; feeble fluorescent signal generated by visible light or infrared agitation is checked by high quantum yield CCD camera. The two checking systems are orthogonally arranged in the same surface, the live nuclear species and fluorescent signal can be checked simultaneously through rotary image cavity, and double module three dimensional tomography image of small animal can be rebuilt with software algorism. The invention is characterized by multi-image forming modules, abundant information and simple operation.

A novel electron multiplier that regulates in real time the gain of downstream dynodes as the instrument receives input signals is introduced. In particular, the methods, electron multiplier structures, and coupled control circuits of the present invention enable a resultant on the fly control signal to be generated upon receiving a predetermined threshold detection signal so as to enable the voltage regulation of one or more downstream dynodes near the output of the device. Accordingly, such a novel design, as presented herein, prevents the dynodes near the output of the instrument from being exposed to deleterious current pulses that can accelerate the aging process of the dynode structures that are essential to the device.

A replaceable, electronically-isolated, MCP-based spectrometer detector cartridge with enhanced sensitivity is disclosed. A mass detector is electro-optically isolated from a charge collector with an electron multiplier for converting a charged particle into a multiplicity of electrons and a scintillator for converting the multiplicity of electrons into a multiplicity of photons. A light sensor is provided to convert the multiplicity of photons back into electrons which are summed into a charge pulse. The light sensor is realized by any of a plurality of photo-responsive devices.

The invention provides a novel series-parallel connection mass spectrum device system. The system comprises mass spectrum necessary basic subsystems, such as a set of quadrupole mass filter system, a special quadrupole rod/linear ion trap mass analyzer system, an ion guidance system, a quadrupole deflector, a hyperbolic quadrupole rod mass analyzer and ion counter system, a low air pressure linear ion trap mass spectrometer and electron multiplier system, a flight time mass spectrum system, a multi-path gas flow control system, a vacuum gauge, a multi-section differential motion vacuum system and the like. Furthermore, the invention provides a method for operating above systems to perform quantitative analysis in a triplet quadrupole rod mode, qualitative analysis in a quadrupole filtering medium combined high/low air pressure ion trap mode, and quick/high-mass precision analysis in a quadrupole filtering combined flight time mass spectrum mode on ultra-trace materials in a complex matrix, a method for utilizing an effective combination of three different mass analyzers to achieve optimal ion optical parameter adjustment and a method for performing high-precision qualitative and quantitative analysis on the ultra-trace materials.

This invention relates to one method to test water total organic carbon, which comprises the following steps: a, sending ozone into TOC reacting room and then into water sample reaction room after filtering and isolator; b, the sample going through heating device and flowing into sample reaction room of TOC reactor through flow pump; c, the ozone and sample reacting in the room to generating optical signals; d, collecting and amplifying the signals sent by the electron-multiplier phototube in the TOC reactor and converting into electrical signals into micro computer process system and after signal processing and comparing data with standard relative curve for displaying and printing and outputting test data.

An ion detector includes an ion input face, a Faraday cup, an ion-to-electron converter dynode, two ion deflection electrodes, an electron multiplier portion, and an anode. The ion input face is formed with an ion input opening. The Faraday cup has an ion collection surface that confronts the ion input opening. The ion-to-electron converter dynode is disposed to one side with respect to the Faraday cup and the ion input opening and has a conversion surface that converts impinging ions into electrons. The two ion deflection electrodes generate an electron lens that attracts and focuses ions from the ion input opening toward the conversion surface of the ion-to-electron converter dynode. The electron multiplier portion receives and multiplies the electrons from the ion-to-electron converter dynode, and includes a plurality of dynodes that multiply electrons one after the other. The plurality of dynodes are juxtaposed in an arc-shape around the Faraday cup. The anode receives electrons from the electron multiplier portion and outputs a signal that corresponds to the amount of input ions.

An electron multiplier for a system for detecting electromagnetic radiation or an ion flow is disclosed. The multiplier includes at least one active structure intended to receive a flow of incident electrons, and to emit in response a flow of electrons called secondary electrons. The active structure includes a substrate on which is positioned a thin nanodiamond layer formed from diamond particles the average size of which is less than or equal to about 100 nm.

An ion detector includes collision surfaces for converting both positively and negatively charged ions into emitted secondary electrons. Secondary electrons may be detected using an electron detector, than may, for example include an electron multiplier. Conveniently, secondary electrons (or electrons emitted by the multiplier) may be detected using an electron pulse counter.

The method discloses a method for determining the age of a uranium-lead decay system in zircon by using the multi-receive secondary ion mass spectroscopy. In the method described according to the invention, a multi-receiver peak jumping receiving mode is used, so that the age of uranium-lead is measured while the accurate age of lead-lead can be obtained. At least five electron multipliers are required to be used as receivers, wherein three of the receivers simultaneously receive the isotopes of lead, and one of the receivers is used for receiving signals required by calculating the age of uranium-lead. The method is applicable to a situation that the ages of uranium-lead and lead-lead can not be simultaneously and accurately measured by using common methods because of low uranium content or extra-small uranium age.

It is flow injection chemical radiation immune detection pool of silane cross-linking polyose film group which is the following: to combine the sensor and the chemical radiation flow pool to make flow injection chemical radiation immune measurement pool; the chemical radiation flow pool comprises the upper plastic board, down transparent board and silicon rubber cushion ring; to open two paths in the upper plastic board as the entrance and exit of the flow transportation; to etch a groove in its inside to embed immune sensor; the down board is glass or organic glass board with good transparency and directly lay them on the down end of electron-multiplier phototube; to adopt silicon rubber cushion ring in the middle as reaction pool where the immune reaction and radiation measurement happens; the immune sensor structure is to process chitose on the silane load surface and fix the antigen molecule and form the new immune sensor.

An electron multiplier detector includes cathode structure defining a plurality of spaced co-planar impact surface segments on which particles impact. These surface segments each have a finite probability of generating at least one electron for each impacting particle having predetermined characteristics. The detector further includes respective sets of electron multiplication dynode segments associated with the impact surface segments, the sets being arranged as substantially parallel arrays extending behind the impact surface segments, and respective means for generating electrostatic and magnetic fields in a space extending from the impact surface segments past the dynode segments, whereby respective streams of electrons cascade and multiply successively along the arrays of dynode segments. Collector structure is provided to receive and detect the streams of electrons downstream of the last dynode segments in the arrays.

The invention discloses an electron multiplier testing device for incident electron source generation by adopting a photoelectric method, and belongs to the field of gain current test of electron multipliers. The electron multiplier testing device comprises a first working table, a first moving guide rail, an ultra-violet lamp holder, an ultra-violet lamp, a filter holder, a light filter, a ultra-violet transmission glass window, an insulating stand, a fixed station, a photocathode frame, a photocathode, a second working table, a second moving guide rail, an electron multiplier frame, an electron multiplier, a vacuum gage, a first flange, a second flange, a vacuum tank, an observation window, a high-voltage source, an electrometer, a molecular pump, a mechanical pump and a temperature-control system. The electron multiplier testing device adopts the photoelectric method for generation of the incident electron source, which has the advantages of simple structure, long service life, stable performance, low cost and the like, and the electron multiplier testing device takes the zinc film as the photocathode, which is simple in preparation, convenient to operate, and good in repeatability.

The invention discloses a high-collecting-efficiency micro-channel plate, a micro-channel plate type photomultiplier and a preparation method thereof. The photomultiplier has a structure which can realize high gain, high collecting efficiency, good single photoelectron spectrum, and collecting efficiency uniformity. The photomultiplier disclosed by the invention comprises a glass ball shell, an electronic focusing barrel, a photocathode and a micro-channel plate electron multiplication system. A metal electrode surface of a first micro-channel plate in an electron incident direction of an electron multiplier of the micro-channel plate type photomultiplier disclosed by the invention and the inner wall surface of a channel are both covered with a thin film with a high secondary electron emission coefficient, so that effective multiplication of electrons can be realized and the high collecting efficiency and the collecting efficiency uniformity of the photomultiplier can be improved.

The invention relates to a method and a device for measuring fire smoke particle Stokes scattering matrix. The invention is characterized in that the laser transmitted by the laser device enters into smoke particles and scatters after modulated by polaroid and electro-light modulator, after the adjustment by a three-dimensional adjusting device, the fire particles are located on the center of the rotary arm rotation; the rotary arm is fixed on a rotary disk and is driven to rotate around the smoke particles by motor controlled by a computer; an aligning eyelet, a 1/4 wave plate, a polaroid and a electron-multiplier phototube are sequentially installed the rotary arm; the signal measured by two electron-multiplier phototubes go through a phase-lock amplifier and is collected by computer, the electro-light modulator and the phase-lock amplifier are synchronized via signal generator.

The present invention relates to an ion trap mass spectrometer using a cold electron source, in a production of a portable mass spectrometer, in which a microchannel plate (MCP) module is used, initial electrons are induced by injecting ultraviolet photons emitted from an ultraviolet diode to a front surface of the MCP module, electron beams amplified from the electrons are amplified using a channeltron electron multiplier (CEM), the amplified electron beams are accurately adjusted and injected into an ion trap, thus increasing the amplification rate, and since a quadrupole field is used as an ion filter which returns the initially injected electrons to the inside of an ion trap mass separator, the ionization rate increases.