Abstract: A metal side tube (2), a glass faceplate (3), and a stem plate (4) constitute a hermetically sealed vessel (5) for a photomultiplier tube. An edge portion (20) is provided at on open end (A) of the side tube (2). The edge portion (2) is embedded in the faceplate (3) in such a manner as to strike on the faceplate (3). Accordingly, high hermeticity at a joint between the side tube (2) and the faceplate (3) is ensured. The edge portion (20) extends upright in an axial direction of the side tube (2), so that the edge portion (20) can be embedded as close to a side face (3c) of the faceplate (3) as possible. This structure increases an effective sensitive area of the faceplate (3) to nearly 100%, and decreases dead area as close to 0 as possible. As described above, the photomultiplier tube (1) according to the present invention has enlarged effective sensitive area of the side tube (3) and enhanced hermeticity of the joint between the faceplate (3) and the side tube (2).

Abstract: A photomultiplier tube enhanced in simplicity and flexibility of mounting, a photomultiplier tube unit enhanced in photomultiplier tube assembling efficiency when unitized, and a radiation detector enhanced in assembling efficiency for a plurality of photomultiplier tubes. The photomultiplier tube (1) has a hermetically sealed vessel (5) easily screw-fixed in a predetermined position due to screwing means (30) provided in the stem plate (4). As a result, the photomultiplier tube (1) can be very easily attached or detached so that even an unskilled person can mount the photomultiplier tube (1) easily and accurately in a predetermined position by screwing.

Abstract: A dynode (8) constituting an electron multiplier or a photomultiplier is provided with eight rows of channels (15) each defined by an outer frame (16) and a partitioning part (17) of the dynode (8). In each channel (15), a plurality of electron multiplying holes (14) are arranged. In specified positions of the outer frame (16) and the partitioning part (17) of the dynode (8), glass receiving parts (21) wider than the outer frame (16) and the partitioning part (17) are provided integrally with the dynode (8). Glass parts (22) are bonded to all the glass receiving parts (21). The glass parts (22) are bonded by applying glass to the glass receiving parts (21) and hardening the glass and each have a generally dome-like convex shape. Each dynode (8) is formed after the dome-like glass part (22) is bonded to the glass receiving part (21).

Abstract: A hermetically sealed vessel for a photomultiplier tube made of a side tube (2), a faceplate and a stem plate. The side tube is made by assembling a plurality of plates (80) with a curled end. An end face (81a) on a corner (81) at an open end of the side tube facing the faceplate is at a higher level than the faces other than the end face (81a). When being heated, the end face (81a) is deeply embedded into the faceplate, which enhances the joint between the side tube and the faceplate. Because the whole open end of the side tube (2) facing the faceplate is embedded into the faceplate, the joint between the side tube (2) and the faceplate is ensured, thereby improving throughput for the joining operation. The side tube is readily integral with the faceplate, which contributes to enhanced hermeticity of the sealed vessel.

Abstract: A photomultiplier tube has a side tube with a stem plate fixed on one end and a faceplate fixed on the other. The side tube is formed of metal, and at least the portion of the stem plate contacting the metal side tube is formed of metal. The side tube and stem plate are fused together by laser welding or electron beam welding to form an airtight vessel, such that the outer edge of the stem plate does not protrude further externally than the outer surface of the side tube.

Abstract: To reduce the size of a photomultiplier tube (1), a side tube (2) is fixedly secured by welding to a stem plate (4) while an inner surface (2c) of the lower portion (2a) of the side tube (2) is maintained to be in contact with an outer edge (4b) of the stem plate (4). As a result, there is no projection like a flange at the lower portion of the photomultiplier tube (1). Therefore, though it is difficult to perform resistance welding, the outside dimensions of the photomultiplier tube (1) can be decreased, and the side tubes (9) can densely abut to one another even if the photomultiplier tubes (2) are arranged when applied. Hence, high-density arrangement of photomultiplier tubes (1) are realized by assembling metallic stem plate (4) and the side tube (2) by, for example, laser welding.

Abstract: In a photomultiplier tube 1, an etching technique is used to form electron multiplying holes 8a in plate-shaped dynodes 8 that are stacked in multiple layers. To perform this etching process, a pattern frame 22 is disposed around a plate-shaped dynode substrate 20. A bridge portion 23 is provided for connecting the pattern frame 22 to an edges 20a of the dynode substrate 20. The dynode substrate 20 is masked, and the etching process is performed to form a plurality of electron multiplying holes 8a in the dynode substrate 20. Subsequently, the bridge portion 23 is cut near the dynode substrate 20, leaving a small bridge remainder 8c on the edge 8b of the dynode 8.

Abstract: An inner surface of an electron-multiplier hole (14) includes a first curved surface (19a) and a second curved surface (19b) that face each other. The first curved surface (19a) extends from an edge of an input opening (14a) in such a way as to face the input opening (14a), and is shaped like a substantially circular arc having a predetermined radius. The second curved surface (19b) extends from an edge of an output opening (14b) in such a way as to face the output opening (14b), and is shaped like a substantially circular arc having a predetermined radius.

Abstract: A dynode (8) constituting an electron multiplier or a photomultiplier is provided with eight rows of channels (15) each defined by an outer frame (16) and a partitioning part (17) of the dynode (8). In each channel (15), a plurality of electron multiplying holes (14) are arranged. In specified positions of the outer frame (16) and the partitioning part (17) of the dynode (8), glass receiving parts (21) wider than the outer frame (16) and the partitioning part (17) are provided integrally with the dynode (8). Glass parts (22) are bonded to all the glass receiving parts (21). The glass parts (22) are bonded by applying glass to the glass receiving parts (21) and hardening the glass and each have a generally dome-like convex shape. Each dynode (8) is formed after the dome-like glass part (22) is bonded to the glass receiving part (21).

Abstract: To prevent the deterioration in sensitivity of the photocathode (20) of an electron tube and maintain stable output for a long time, an ion confining electrode (22) and an ion trap electrode (23) are provided between the photocathode (20) and a first stage dynode (24a). The potential of the ion confining electrode (22) is set higher than that of the first stage dynode (24a), while the potential of the ion trap electrode (23) is set equal to or higher than that of the photocathode (20) and lower than that of the first stage dynode 24a. Since the feedback to the photocathode (20) of the positive ions generated in the vicinity of the first stage dynode can be effectively suppressed, the sensitivity of the photocathode (20) is prevented from decreasing, and stable output is maintained for a long time.

Abstract: A photomultiplier tube unit including photomultiplier tubes densely assembled and thereby having an improved light sensing efficiency. The outer surfaces (2b) of metal side tubes (2) of photomultiplier tubes (1) are in facial contact with one another, and thereby a high-density arrangement of photomultiplier tubes (1) are achieved. The side tubes (2) can be electrically connected to one another, and therefore the side tubes (2) can be easily made equipotential. As a result, it is unnecessary to electrically connect the stem pin (10) to the side tube (2) of each photomultiplier tube (1), facilitating the assembling of the photomultiplier tube unit. When a required photomultiplier tube (1) in a device (e.g., a gamma camera) having thus-united multiple photomultiplier tubes is replaced with a new one, the troublesome work of replacing photomultiplier tubes one by one is obviated, simplifying the replacement work.

Abstract: In the electron multiplier assembly 27, a dynode unit 10 is constructed from a plurality of dynodes 9 laminated one on another. Each dynode 9 is formed with multichannels 12 which are separated from one another by channel-separating portions 14. A focusing electrode plate 16 is formed with multichannels 18 which are separated from one another by channel-separating electrodes 20 which are located in correspondence with the channel-separating portions 14 of the first stage dynode 9a. A plurality of anodes 7 are provided for receiving electrons multiplied at the dynode unit 10 in their corresponding channels 18. Each channel-separating electrode 20 is formed with an opening 21, at a position confronting the channel-separating portion 14 of the first stage dynode 9a, for transmitting electrons therethrough.

Abstract: According to the photomultiplier tube, the dynode unit 10 is constructed from a plurality of stages of dynodes 11 laminated one on another for multiplying incident electrons in a cascade manner through each of a plurality of channels. The anode unit 13 has a plurality of anodes 24 which define a plurality of electron passage gaps 14 each for transmitting the electrons emitted from the dynode unit 10 at a corresponding channel. The inverting dynode plate 15 is provided with a plurality of electron incident strips 17 each for receiving electrons having passed through a corresponding electron passage gap 14 in the anode unit 13, multiplying the electrons, and guiding the electrons back to the corresponding anode 24.

Abstract: In the photomultiplier tube 1, the focusing electrode plate 17 has the focusing portion 20 for focusing incident electrons and the frame 21 surrounding the focusing portion 20. The focusing portion 20 has a plurality of slit openings 18. The dynode unit 10 is constructed from a plurality of dynode plates 11 laminated one on another. Each dynode plate 11 has a plurality of electron through-holes 13 located in confrontation with the plurality of slit openings 18. A plurality of anodes 9 are provided for receiving electrons emitted from the respective through-holes 13 of the dynode unit 10. The frame 21 has dummy openings 22 at positions located in confrontation with edges 15 of the first stage dynode plate 11a in the dynode unit 10.

Abstract: A photomultiplier of the present invention has an electron multiplier of a structure which can be manufactured easily. This electron multiplier is constituted by dynode plates that are stacked through insulators so as to be separated from each other at a predetermined interval. Each dynode plate comprises upper- and lower-electrode plates that are electrically connected to each other. The upper- and lower-electrode plates grip at least one of the insulators such that the gripped insulator is partly exposed.

Abstract: A photomultiplier is constituted by a photocathode and an electron multiplier having a typical structure in which a dynode unit having a plurality of dynode plates stacked in an incident direction of photoelectrons, an anode plate, and an inverting dynode plate are sequentially stacked. Through holes for injecting a metal vapor are formed in the inverting dynode plate to form secondary electron emitting layers on the surfaces of dynodes supported by the dynode plates, and the photocathode. With this structure, the secondary electron emitting layers are uniformly formed on the surfaces of the dynodes. Therefore, variations in output signals obtained from anodes can be reduced regardless of the positions of the photocathode.

Abstract: An electron tube includes an electron multiplication unit for multiplying an incident electron flow by secondary electron emission. This electron multiplication unit is formed by stacking a plurality of dynodes toward an incident side of the electron flow. A plurality of through holes are arranged and formed in each dynode, in which one end on the incident side of the electron flow is used as an input opening, and the other end is used as an output opening. An acceleration electrode unit projecting toward the through hole of the upper dynode is provided at an edge portion of the input opening. As described above, the acceleration electrode unit is provided at the edge portion of the input opening of the through hole formed in each dynode. For this reason, a damping electric field is pushed up by the acceleration electrode unit and deeply warped into the through hole of the upper dynode.

Abstract: In a photomultiplier tube, a second dynode Dy2 is located in confrontation with a first dynode Dy1 in an electron multiplication portion 6. The second dynode Dy2 is made of material that has a secondary electron emission gain which is substantially saturated with respect to an electric voltage applied thereto.

Abstract: An electron multiplier includes an improved resistor assembly for applying relevant voltages to respective dynodes. Resistor patterns are printed on one surface of an insulation substrate. Each resistor pattern is connected to one end of one of a plurality of conductor patterns which are also printed on the same surface of the insulation substrate, so that each resistor pattern is sandwiched between adjacent conductor patterns to provide a predetermined resistance therebetween. The other end of each conductor pattern extends to a corresponding insertion hole formed on the insulation substrate. One end of a conductor element, which may be a lead, wire, or other wire shaped conductor, is inserted into the corresponding insertion hole and electrically connected to its corresponding conductor pattern. At least the area around where the conductor pattern is connected to the conductor element and also areas around resistor patterns are covered with an insulating seal material.

Abstract: 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.