摘要:
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.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
In a method comprising a modified region forming step of converging a laser light at a sheet-like object to be processed made of silicon so as to form a plurality of modified spots within the object along a modified region forming line tilted in a first lateral direction with respect to a thickness direction of the object and the plurality of modified spots construct a modified region, and an etching step of anisotropically etching the object after the modified region forming step so as to advance the etching selectively along the modified region and form the object with a space extending obliquely with respect to the thickness direction, the modified region forming step forms the plurality of modified spots such that the modified spots adjacent to each other at least partly overlap each other when seen in the first lateral direction.
摘要:
The photomultiplier tube 1 is provided with an electron multiplying part 33 having a plurality of stages of dynodes 33a to 33l arrayed along a direction at which electrons are multiplied on an inner surface 40a of a casing 5 and a photocathode 41 and an anode part 34 installed so as to be spaced away form the electron multiplying part 33 inside the casing 5. Each of the dynode 33c to 33e is provided with a plurality of columnar parts 51c to 51e where secondary electron emitting surfaces 53c to 53e are formed, thereby forming electron multiplying channels C between adjacent columnar parts. An opposing surface 54e which opposes a columnar part 51d which is a previous stage at a columnar part 51e which is a subsequent stage is formed in such a manner that both end parts 56e, 57e in a direction along the inner surface 40a of the opposing surface 54e project to the first end side from a site 55e which opposes the end part of the second end side on the secondary electron emitting surface 53d of the columnar part 51d.
摘要:
The present invention relates to a photomultiplier that realizes a significant improvement of response time characteristics by a structure enabling mass production. The photomultiplier comprises a sealed container, and, in the sealed container, a photocathode, an electron multiplier section, and an anode are respectively disposed. The electron multiplier section includes multiple stages of dynode units, and each of the multiple stages of dynode units is fixed with one end of the associated dynode pin while being electrically connected thereto. In particular, the dynode pin, whose one ends are fixed to the multiple stages of dynode units, are held within an effective region of the electron multiplier section contributing to secondary electron multiplication, when the electron multiplier section is viewed from the photocathode side. By this configuration, a focusing distance from the photocathode to a first stage dynode unit can be shortened effectively and the effective region of the electron multiplier section can be enlarged to effectively reduce variations in transit time of photoelectrons propagating from the photocathode to the first stage dynode unit.
摘要:
The present invention relates to a photomultiplier having a fine structure capable of realizing high multiplication efficiency. The photomultiplier comprises a housing whose inside is maintained vacuum, and, on a device mounting surface which is a part of an inner wall surface defining an internal space of the housing, a photocathode serving as a reflection type photocathode, an electron-multiplier section, an anode, and a voltage distributing section are disposed integrally. In particular, the electron-multiplier section is constituted by dynodes at multiple stages cascade-multiplying photoelectrons from the photocathode, and the voltage distributing section, which applies corresponding voltages to the dynodes at the respective stages respectively, is on the same surface together with the electron-multiplier section.
摘要:
An object is to sufficiently keep the airtightness in a vacuum container even when it is made smaller. A photomultiplier tube 1 comprises a flat sheet-like lower substrate 4, a casing-like frame 3b erected on the lower substrate 4, an upper substrate 2 including a frame 3a airtightly joined to an opening part of the frame 3b while holding a low-melting metal therebetween, and a frame-like projection 25b arranged in parallel with the frame 3b on the inner side of the frame 3b on the lower substrate 4.
摘要:
The present invention relates to a photomultiplier having a fine structure capable of realizing high detection accuracy by effectively suppressing cross talk among electron-multiplier channels. The photomultiplier comprises a housing whose inside is maintained vacuum, and, in the housing, a photocathode, an electron-multiplier section, and anodes are disposed. The electron-multiplier section has groove portions for cascade-multiplying photoelectrons as electron-multiplier channels, and the anodes are constituted by channel electrodes corresponding to the groove portions respectively defined by wall parts. In particular, at least parts of the respective channel electrodes are located in spaces sandwiched between pairs of wall parts defining the corresponding groove portions.