A photomultiplier tube comprising a photocathode, a plurality of mesh dynodes arranged parallel to the photocathode, an anode that is disposed in a face-to-face relationship with the photocathode in such a manner that the mesh dynodes are interposed between the anode and the photocathode, the anode being divided into segments larger than the openings of each dynode, and at least one layer of focusing electrode for focusing an electron beam by the lens action which is disposed between the photocathode and the anode.
The present invention pertains to a photomultiplier of head-on type that has a transparent tubular glass bulb and a principal photocathode formed on the internal surface of a closed end of the glass bulb, that is, on the internal surface of a light entrance window. In addition, this photomultiplier has a side photocathode formed on the entire internal surface of side wall of the glass bulb in the region adjacent to the principal photocathode. A reflection film is formed on the outer surface of side wall of the glass bulb and opposes to the side photocathode. Some light entering the peripheral portion of the light entrance window of the glass bulb and traveling toward the outer surface of side wall is reflected inwardly by the reflection film and reaches the side photocathode, where the light is to be converted into photoelectrons. The photoelectrons are guided to the electron multiplying unit in glass bulb, where the photoelectrons are multiplied and detected by an anode.
A multiple section photomultiplier tube constructed as a matrix of several independent tubes in one envelope. The photocathode to dynode spacings are isolated by a separator configuration built with walls which interlock in cooperating slots, and each photocathode operates with its own independent dynode cage. One dynode in each cage is maintained electrically independent, and its connection is brought out of the envelope independently. This permits independent adjustment of the gain for each of the tube's multiple sections, so they can be adjusted to the same response for a standard radiation signal. The entire tube can then be used to monitor a large area for radiation, and will yield the same response over its entire cathode area.
A venetian-blind type of photomultiplier tube comprising a photocathode for converting an incident light into photoelectrons, a venetian-blind type of dynode array comprising plural dynode rows arranged in a first direction, each of which comprises plural dynode elements arranged at a constant pitch in a second direction, each dynode element having a plate inclined to the first direction for emitting the secondary electrons, an anode array comprising plural anodes arranged in the second direction for collecting the secondary electrons emitted from the dynode array and outputting an amplified electrical signal corresponding to the light, and one or more electron converging electrodes for converging at least one stream of the photoelectrons and the secondary electrons and concentrically directing the converged stream to a predetermined portion of each of the dynode elements. The electron-flight control member may have various patterns such as a grid, strip, mesh and multi-aperture structures.
A photomultiplier tube comprises a photocathode (10) deposited on an input window (20) sealed to one end of a sleeve (30), an input electrode (40), and an electron multiplier (50) with stacked dynodes. The input electrode (40) is constituted by a truncated cone conductor on the inside of which the electron multiplier (50) with stacked dynodes is deposited. A generator (61,62) of a material forming the photocathode (10) is advantageously placed in the space (70) situated between the input electrode (40) and the sleeve (30).
This invention relates to a photomultiplier for detecting the incident position of a plane of incidence, where a weak light beam is reached and to a photomultiplier having a structure for minimizing crosstalk near the incident position of the weak light beam to improve the precision of the position resolving power. Particularly, the anode of this photomultiplier, which extracts the incident position of the incident weak light as an electrical signal, is constituted by a first anode component for detecting the incident position of the incident plane in the X direction and a second anode component for detecting the incident position of the incident plane in the Y direction. The first and second anode components have flat surfaces. These flat surfaces cause the first and second anode components to capture secondary electrons emitted from a dynode in correspondence with the incident position of the weak light beam, at a position closer to the emission position. The photomultiplier detects the incident position of the weak light beam at a higher resolving power while minimizing the crosstalk.
