Abstract: A streak tube 1A comprises an envelope 10 including an entrance faceplate 12; a photocathode 20 for converting light received from the entrance faceplate 12 into an electron; an anode 23 having an opening 23a for passing there through the electron emitted from the photocathode 20; deflecting electrodes 24 for controlling a deflection of the electron having passed through the opening 23a of the anode; and a fluorescent screen 25 for detecting a streak image due to the electron having the deflection controlled by the deflecting electrodes 24. The photocathode 20 is configured so as to be kept from directly facing the anode 23 on an axis of an electric field formed between the entrance faceplate 12 and the anode 23 or on a tube axis passing the center of the opening 23a in the anode 23 within the envelope 10. Thus, the streak tube capable of suppressing influences of noise signals on signals corresponding to incident light can be realized.

Abstract: Provided are a photocathode plate capable of stably achieving a high sensitive property, and an electron tube using such a photocathode plate. In a photomultiplier tube 1, an insulating layer 63 is formed between a semiconductor electron emission layer 51 in a photocathode plate 23A, and a first electrode 65 electrically connected to an electron releasing portion 59. This insulating layer 63 permits the photocathode plate 23A to be cleaned by heat cleaning at a high temperature, in a stage before formation of an active layer 61 on an exposed region of the semiconductor electron emission layer 51 in the electron releasing portion 59. This makes it feasible to effectively clean the exposed region of the semiconductor electron emission layer 51 in the electron releasing portion 59 and to stabilize the physical properties of the exposed region. In consequence, a higher sensitive property can be stably achieved in the photocathode plate 23A and in the photomultiplier tube 1 using the photocathode plate 23A.

Abstract: A streak tube 1A comprises an envelope 10 including an entrance faceplate 12; a photocathode 20 for converting light received from the entrance faceplate 12 into an electron; an anode 23 having an opening 23a for passing therethrough the electron emitted from the photocathode 20; deflecting electrodes 24 for controlling a deflection of the electron having passed through the opening 23a of the anode; and a fluorescent screen 25 for detecting a streak image due to the electron having the deflection controlled by the deflecting electrodes 24. The photocathode 20 is configured so as to be kept from directly facing the anode 23 on an axis of an electric field formed between the entrance faceplate 12 and the anode 23 or on a tube axis passing the center of the opening 23a in the anode 23 within the envelope 10. Thus, the streak tube capable of suppressing influences of noise signals on signals corresponding to incident light can be realized.

Abstract: Provided are a photocathode plate capable of stably achieving a high sensitive property, and an electron tube using such a photocathode plate. In a photomultiplier tube 1, an insulating layer 63 is formed between a semiconductor electron emission layer 51 in a photocathode plate 23A, and a first electrode 65 electrically connected to an electron releasing portion 59. This insulating layer 63 permits the photocathode plate 23A to be cleaned by heat cleaning at a high temperature, in a stage before formation of an active layer 61 on an exposed region of the semiconductor electron emission layer 51 in the electron releasing portion 59. This makes it feasible to effectively clean the exposed region of the semiconductor electron emission layer 51 in the electron releasing portion 59 and to stabilize the physical properties of the exposed region. In consequence, a higher sensitive property can be stably achieved in the photocathode plate 23A and in the photomultiplier tube 1 using the photocathode plate 23A.

Abstract: In the case of a thick light-absorbing layer 2, a phenomenon of a decrease in the time resolution occurs. However, when the thickness of the light-absorbing layer 2 is limited, a portion of low electron concentration in one electron group is cut out, and hence overlap regions of adjacent electron concentration distributions decrease. Therefore, by shortening the transit time necessary for the passage of electrons, regions of overlapping electron distributions due to diffusion can also be suppressed. Furthermore, the strength of an electric field within a light-absorbing layer can be increased by thinning the light-absorbing layer. Therefore, the time resolution of infrared rays can be remarkably improved by a synergistic action of these effects. If it is assumed that the time resolution is 40 ps (picoseconds), for example, when the thickness of a light-absorbing layer is 1.3 ?m which is nearly equal to the wavelength of infrared, then a possible time resolution is 7.5 ps when this thickness is 0.19 ?m.

Abstract: A photocathode and an electron tube in which the photocathode plate can be securely fixed without using any adhesive. Even under the severe condition that a high vibration resistance is required or thermal stress occurs because of great temperature variation, it can be used widely for an image intensifier, a streak tube, or a photomultiplier. The photocathode plate of the photocathode is sandwiched between a faceplate and a support plate. First pins embedded in the faceplate are joined to the support plate. Therefore, the photocathode plate can be readily fixed securely to the faceplate without using any adhesive.

Abstract: In the case of a thick light-absorbing layer 2, a phenomenon of a decrease in the time resolution occurs. However, when the thickness of the light-absorbing layer 2 is limited, a portion of low electron concentration in one electron group is cut out, and hence overlap regions of adjacent electron concentration distributions decrease. Therefore, by shortening the transit time necessary for the passage of electrons, regions of overlapping electron distributions due to diffusion can also be suppressed. Furthermore, the strength of an electric field within a light-absorbing layer can be increased by thinning the light-absorbing layer. Therefore, the time resolution of infrared rays can be remarkably improved by a synergistic action of these effects. If it is assumed that the time resolution is 40 ps (picoseconds), for example, when the thickness of a light-absorbing layer is 1.3 &mgr;m which is nearly equal to the wavelength of infrared, then a possible time resolution is 7.5 ps when this thickness is 0.

Abstract: A photocathode and an electron tube in which the photocathode plate can be securely fixed without using any adhesive. Even under the severe condition that a high vibration resistance is required or thermal stress occurs because of great temperature variation, it can be used widely for an image intensifier, a streak tube, or a photomultiplier. The photocathode plate of the photocathode is sandwiched between a faceplate and a support plate. First pins embedded in the faceplate are joined to the support plate. Therefore, the photocathode plate can be readily fixed securely to the faceplate without using any adhesive.

Abstract: A voltage control section for controlling a pulsed acceleration voltage applied between a photoelectron releasing layer and an X-ray target in order to accelerate a photoelectron is further provided, so that the acceleration voltage is maintained at a pulse top voltage until the X-ray target is bombarded with the photoelectron after the photoelectron is released from the photoelectron releasing layer. The pulse width of acceleration voltage can be set narrower to such an extent that no discharge occurs, which enables the pulse top voltage to become higher, whereby the energy of pulse X-rays can be made higher by enhancing the speed of photoelectrons.

Abstract: A voltage control section for controlling a pulsed acceleration voltage applied between a photoelectron releasing layer and an X-ray target in order to accelerate a photoelectron is further provided, so that the acceleration voltage is maintained at a pulse top voltage until the X-ray target is bombarded with the photoelectron after the photoelectron is released from the photoelectron releasing layer. The pulse width of acceleration voltage can be set narrower to such an extent that no discharge occurs, which enables the pulse top voltage to become higher, whereby the energy of pulse X-rays can be made higher by enhancing the speed of photoelectrons.

Abstract: An imaging tube having a fiber optic plate (FOP) as an output faceplate. On one surface of the FOP within an evacuated envelope is deposited a first transparent conductive layer. On the first transparent conductive layer is deposited a fluorescent layer. On the fluorescent layer is deposited a metal-back electrode. On the other surface of the FOP outside the evacuated envelope is deposited a second transparent conductive layer. The first transparent conductive layer and the metal-back electrode are electrically connected so that an electrical field is not developed across the fluorescent layer when the metal-back electrode is applied with a high positive voltage and the second transparent conductive layer is grounded. Therefore, even if leakage currents flow through the FOP, electric charges impinging upon the first transparent conductive layer will not cause the fluorescent layer to generate noise spots.