Striped tube

Abstract

A streak tube according to one embodiment is provided with: a container having an input panel and an output panel; a photoelectric surface; a scanning electrode; a plurality of electrodes that are provided between the photoelectric surface and the scanning electrode, form an electron lens that focuses electrons, and are each provided with an opening through which the electrons pass; and a control unit that controls a potential applied to at least one of the plurality of electrodes. The plurality of electrodes includes: a first electrode disposed at a position closest to the incident panel; a second electrode disposed at a position closest to the output panel; and a third electrode disposed between the first electrode and the second electrode so as to be separated from the first electrode and the second electrode. The control unit applies a potential higher than the potential of the first electrode and the potential of the second electrode to the third electrode.

Description

Technical Field

[0001] The present disclosure relates to a streak tube. Background Art

[0002] As a device for capturing phenomena that occur in a short time along with light, a streak tube is known (for example, refer to Patent Document 1). The streak tube disclosed in Patent Document 1 has a structure in which three additional electrodes forming a one-dimensional focusing lens are arranged in the tube axis direction between an electron focusing system that focuses electrons generated by a photoelectric surface and a scanning electrode. In this streak tube, in order to improve the time resolution, a ground potential (0 V) is applied to the first additional electrode and the third additional electrode arranged on both outer sides among the three additional electrodes, and a negative potential (for example, -350 V or -500 V) is applied to the second additional electrode arranged between the first additional electrode and the third additional electrode.

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: Japanese Patent No. 5824328 Gazette Summary of the Invention

[0006] Problems to be Solved by the Invention

[0007] In recent years, in the high-energy field (for example, research on high-energy accelerator electron beams, development of ultrashort pulse light sources, etc.), the scientific measurement field (for example, measurement of molecular dynamics in the field of material development research, etc.), etc., the demand for ultra-high-speed optical measurement for capturing luminescence phenomena generated in an extremely short time has increased. That is, in the above-mentioned streak tube (for example, a structure that performs synchronous scanning in which the time resolution is likely to deteriorate, etc.), a further improvement in time resolution is sought.

[0008] Therefore, an object of one aspect of the present disclosure is to provide a streak tube capable of effectively improving the time resolution.

[0009] Technical Means for Solving the Problems

[0010] The present disclosure includes the following streak tubes [1] to

[10] . [1]

[0012] A streak tube, comprising:

[0013] A container having an incident panel and an output panel;

[0014] A photoelectric surface provided inside the container, which releases electrons according to the light to be measured incident from the incident panel;

[0015] A scanning electrode, which is disposed within the container and is composed of a pair of plate-shaped electrodes that face each other in the scanning direction along the output panel, scans the electrons in the scanning direction;

[0016] A plurality of electrodes, which are disposed between the photoelectric surface and the scanning electrode, form an electron lens for focusing the electrons, and are respectively provided with openings for the electrons to pass through; and

[0017] A control unit, which controls the potential applied to at least one of the plurality of electrodes,

[0018] The plurality of electrodes include: a first electrode, which is disposed at the position closest to the incident panel; a second electrode, which is disposed at the position closest to the output panel; and a third electrode, which is disposed between the first electrode and the second electrode separately from the first electrode and the second electrode,

[0019] The control unit applies a potential higher than the potential of the first electrode and the potential of the second electrode to the third electrode.

[0020] In the above-described streak tube, a potential higher than the potential of the first electrode and the potential of the second electrode is applied to the third electrode disposed closer to the inside than the first electrode and the second electrode located at both ends among the plurality of electrodes forming the electron lens. Here, if a potential lower than the potential of the first electrode and the second electrode is applied to the third electrode, an electron deceleration region that decelerates the speed of the electrons is formed near the opening on the electron incident side of the third electrode. In contrast, according to the above-described streak tube in which a potential higher than the potential of the first electrode and the second electrode is applied to the third electrode, formation of the above-described electron deceleration region can be suppressed, and the electrons near the opening on the electron incident side of the third electrode can be accelerated. Further, among the electron group passing through the electron lens, the electrons passing through the orbit farther from the central plane of the electron lens are subjected to a stronger acceleration effect caused by the potential difference. As a result, the speed difference (i.e., arrival time difference to the scanning electrode) between the electrons of the electron group after passing through the electron lens generated by the electron group passing through the electron lens can be reduced. Therefore, according to the above-described streak tube, the time resolution can be effectively improved. [2]

[0022] The streak tube according to [1], wherein,

[0023] The first electrode and the second electrode have the same potential.

[0024] By setting the first electrode and the second electrode to the same potential, the time resolution can be improved more effectively. [3]

[0026] The streak tube according to [1] or [2], wherein,

[0027] It further includes: a first slit member disposed between the electron lens and the scanning electrode, and having a first slit with a width smaller than the width of each of the openings of the plurality of electrodes in the scanning direction.

[0028] The control unit, by controlling the potential applied to the scanning electrode, applies a positive potential to one of the pair of plate electrodes, i.e., the first plate electrode, and a negative potential to the other of the pair of plate electrodes, i.e., the second plate electrode, at the start of scanning of the scanning electrode.

[0029] The center of the first slit in the scanning direction is disposed at a position separated from the center plane passing through the center of the electron lens and orthogonal to the scanning direction, on the side where the first plate electrode is located.

[0030] In the region between the first plate electrode and the second plate electrode, on the electron incident side closer to the second plate electrode than the center plane, by generating a negative electric field at the start of scanning, it becomes a deceleration region where electrons are easily decelerated. On the other hand, in the region between the first plate electrode and the second plate electrode, on the electron incident side closer to the first plate electrode than the center plane, by generating a positive electric field at the start of scanning, it becomes an acceleration region where electrons are easily accelerated. According to the above structure, it is possible to shield a part of the electron group in the electron group after passing through the electron lens that is directed towards the deceleration region (i.e., the electrons passing through the peripheral portion farther from the side where the second plate electrode is located than the center plane), and reduce the number of electrons entering the deceleration region. Thereby, it is possible to suppress the deviation of the speed and the advancing direction (angle) of the electron group entering between the first plate electrode and the second plate electrode. As a result, it is possible to suppress the spatial expansion of the scanning direction (time direction) of the electron group reaching the output panel, and improve the time resolution. [4]

[0032] The streak tube according to [3], wherein

[0033] the first slit member and the second electrode are at the same potential.

[0034] By setting the first slit member and the second electrode at the same potential, it is possible to more effectively improve the time resolution. [5]

[0036] The streak tube according to any one of [1] to [4], wherein

[0037] It further includes: a second slit member disposed between the electron lens and the incident panel, and having a second slit with a width smaller than the width of each of the openings of the plurality of electrodes in the scanning direction.

[0038] When starting the scan of the scanning electrode, the control unit applies a positive potential to one of the pair of plate electrodes, i.e., the first plate electrode, and a negative potential to the other of the pair of plate electrodes, i.e., the second plate electrode, by controlling the potential applied to the scanning electrode.

[0039] The center of the second slit in the scanning direction is disposed at a position separated from the center plane that passes through the center of the electron lens and is orthogonal to the scanning direction, on the side where the second plate electrode is located.

[0040] According to the above structure, it is possible to shield a part of the electrons in the electron group incident on the electron lens that pass through the peripheral portion farther from the first plate electrode than the center plane. As a result, it is possible to suppress the deviation of the velocity and the traveling direction (angle) of the electron group that enters between the first plate electrode and the second plate electrode (i.e., the deviation of the arrival time at the scanning electrode) caused by the electron group passing through the electron lens. As a result, it is possible to suppress the spatial spread of the scanning direction (time direction) of the electron group reaching the output panel and improve the time resolution. [6]

[0042] The streak tube according to [5], wherein

[0043] It further includes: an aperture electrode, which is disposed between the second slit member and the incident panel and is provided with an opening for allowing the electrons to pass through.

[0044] The second slit member has the same potential as at least one of the aperture electrode and the first electrode.

[0045] By setting the second slit member to have the same potential as at least one of the aperture electrode and the first electrode, it is possible to more effectively improve the time resolution. [7]

[0047] The streak tube according to any one of [1] to [6], wherein

[0048] The incident panel has a light incident surface for the incident light to be measured and a photoelectric surface forming surface located on the side opposite to the light incident surface and formed with the photoelectric surface.

[0049] The photoelectric surface forming surface is formed in a curved shape that is concave toward the light incident surface side.

[0050] According to the above structure, in the forward direction of the electrons (i.e., the direction from the incident panel toward the output panel), the distance difference between the focusing points of the electrons released from positions near the center of the photocathode and the focusing points of the electrons released from positions far from the center of the photocathode can be reduced. As a result, the resolution (spatial resolution) in the spatial direction (the direction orthogonal to the scanning direction and the forward direction of the electrons) caused by the difference in the electron release positions on the photocathode (i.e., the incident positions of the measured light on the photocathode) can be improved. [8]

[0052] A streak tube according to any one of [1] to [7], wherein

[0053] At the start of scanning of the scanning electrode, the control unit applies a positive potential to one of the pair of plate electrodes, i.e., the first plate electrode, and applies a negative potential to the other of the pair of plate electrodes, i.e., the second plate electrode, by controlling the potential applied to the scanning electrode.

[0054] The distance between the end closest to the incident panel on the inner side of the first plate electrode facing the center plane passing through the center of the electron lens and orthogonal to the scanning direction and the center plane is shorter than the distance between the end closest to the incident panel on the inner side of the second plate electrode facing the center plane and the center plane.

[0055] According to the above structure, the electron group after passing through the electron lens can be appropriately guided to the region (acceleration region) close to the first plate electrode to which a positive potential is applied at the start of scanning, and the electrons incident on the region (deceleration region) close to the second plate electrode to which a negative potential is applied at the start of scanning can be reduced. As a result, the deviation in the arrival time of electrons to the scanning electrode generated when the electron group passes through the electron lens is reduced. As a result, the time resolution can be more effectively improved. [9]

[0057] A streak tube according to any one of [1] to [8], wherein

[0058] The pair of plate electrodes are traveling-wave type electrodes configured such that the applied potential changes synchronously with the traveling speed of the electrons between the pair of plate electrodes.

[0059] According to the above structure, the speed of the electrons passing between the scanning electrodes can be matched, and the potential propagating between the scanning electrodes can be applied. As a result, since more precise scanning control of the electron group can be achieved, the time resolution can be more effectively improved.

[10]

[0061] A streak tube, comprising:

[0062] A container having an incident panel and an output panel;

[0063] A photoelectric surface disposed within the container that releases electrons in accordance with the light to be measured incident from the incident panel;

[0064] A scanning electrode disposed within the container, formed by a pair of plate-shaped electrodes opposed to each other in the scanning direction along the output panel, that scans the electrons in the scanning direction;

[0065] A plurality of electrodes disposed between the photoelectric surface and the scanning electrode, forming an electron lens that focuses the electrons and each provided with an opening through which the electrons pass;

[0066] A control unit that controls the potential applied to the scanning electrode and the potential applied to at least one of the plurality of electrodes;

[0067] A first slit member disposed between the electron lens and the scanning electrode and having a first slit with a width smaller than the width of each of the openings of the plurality of electrodes in the scanning direction; and

[0068] A second slit member disposed between the electron lens and the incident panel and having a second slit with a width smaller than the width of each of the openings of the plurality of electrodes in the scanning direction,

[0069] When the scanning of the scanning electrode starts, the control unit applies a positive potential to one of the pair of plate-shaped electrodes, i.e., the first plate-shaped electrode, and applies a negative potential to the other of the pair of plate-shaped electrodes, i.e., the second plate-shaped electrode.

[0070] The center of the first slit in the scanning direction is disposed at a position separated from the center plane passing through the center of the electron lens and orthogonal to the scanning direction, on the side where the first plate-shaped electrode is located.

[0071] The center of the second slit in the scanning direction is disposed at a position separated from the center plane, on the side where the second plate-shaped electrode is located.

[0072] According to the above structure, since the effects of both [3] and [5] above can be obtained, the time resolution can be effectively improved.

[0073] Effects of the Invention

[0074] According to one aspect of the present disclosure, a streak tube capable of effectively improving the time resolution can be provided. Description of the Drawings

[0075] Figure 1It is a cross-sectional view schematically showing the structure of the streak tube according to the first embodiment.

[0076] Figure 2 It is schematically represented Figure 1 A three-dimensional cross-sectional view of a portion of the aperture electrode, the second slit component, the one-dimensional electron lens, and the first slit component in the streak tube.

[0077] Figure 3 Yes Figure 1 A diagram showing an example of a scanning voltage applied to a scanning electrode of a streak tube.

[0078] Figure 4 It is a diagram schematically showing the operation of the one-dimensional electron lens of each of the comparative example and the example.

[0079] Figure 5 It is a diagram schematically showing the operation of the photoelectric element in each of the comparative example and the example.

[0080] Figure 6 It is a diagram schematically showing the operation of the photoelectric element in each of the comparative example and the example.

[0081] Figure 7 It is a cross-sectional view schematically showing a modified example of the one-dimensional electron lens.

[0082] Figure 8 It is a cross-sectional view schematically showing the structure of a streak tube according to the second embodiment.

[0083] Figure 9 It is schematically represented Figure 8 A three-dimensional cross-sectional view of a portion of the aperture electrode, the second slit component, the one-dimensional electron lens, and the first slit component in the streak tube.

[0084] Figure 10 This is a diagram schematically showing the results of time resolution analysis of a streak tube according to a comparative example.

[0085] Figure 11 This is a diagram schematically showing the results of the temporal resolution analysis of the streak tube according to the first embodiment.

[0086] Figure 12 This is a diagram schematically showing the results of the temporal resolution analysis of the streak tube according to the second embodiment.

[0087] Figure 13 Graphs showing measurement results of the temporal resolution of the streak tube of the first embodiment and the streak tube of the second embodiment.

[0088] Figure 14 Schematic diagrams showing first and second variations of the scan electrodes.

[0089] Figure 15 It is a diagram schematically showing a third modified example of a scanning electrode.

[0090] Figure 16 It is a diagram schematically showing a modified example of a main focusing electrode. Detailed implementation mode

[0091] Hereinafter, with reference to the drawings, a specific implementation mode of the present disclosure will be described in detail. In addition, in the following description, the same or equivalent elements are denoted by the same reference numerals, and repeated descriptions are omitted.

[0092] [First Embodiment]

[0093] Refer to Figures 1 to 7 and describe the streak tube 1A of the first embodiment. Figure 1 It is a sectional view along a plane including the tube axis A of the streak tube 1A and perpendicular to the deflection plates (plate electrodes 6a, 6b) of the scanning electrode 6. As Figure 1 shown, the streak tube 1A includes a container 2, a mesh electrode 3, a main focusing electrode 4, an aperture electrode 5, a scanning electrode 6, a photocathode 7, a fluorescent screen 8, a one-dimensional electron lens 9, a first slit member 11, a second slit member 12, a high-voltage power supply 13, a voltage distribution circuit 14, a voltage source 15 for the main focusing electrode, a voltage source 16 for the third electrode, a scanning voltage generation unit 17, a setting signal generation unit 18 (control unit), a PIN photodiode 19, and a delay circuit 20.

[0094] The container 2 is formed in a cylindrical shape. The tube axis A of the above-mentioned streak tube 1A is the central axis of the container 2. An incident panel 2a made of a light-transmissive material for the incident measurement light L is fixed to one end surface of the container 2 in the direction along the tube axis A. The incident panel 2a has a light incident surface 2a1 for the incident measurement light L and a photocathode formation surface 2a2 located on the side opposite to the light incident surface 2a1. An output panel 2b made of a light-transmissive material for outputting the output image is fixed to the other end surface of the container 2 in the direction along the tube axis A. In addition, in the following description, the direction along the tube axis A of the container 2 is set as the Z-axis direction, the direction (scanning direction) in which the plate electrodes 6a (first plate electrode) and 6b (second plate electrode) of the scanning electrode 6 face each other and are orthogonal to the Z-axis direction is set as the X-axis direction, and the direction (spatial direction) orthogonal to the Z-axis direction and the X-axis direction is set as the Y-axis direction.

[0095] Inside the container 2, the light-receiving surface 2a2 on the inner side of the incident panel 2a, i.e., the photocathode-forming surface, is formed into a curved surface that is concave toward the light-incident surface 2a1, and a photocathode 7 is provided thereon. In other words, the photocathode 7 is provided on the photocathode-forming surface 2a2 and is formed into a curved surface that protrudes from the output panel 2b toward the incident panel 2a. As an example, a concave portion having a curved surface shape is provided on the photocathode-forming surface 2a2, and the photocathode 7 is formed such that the thickness in the Z-axis direction is substantially constant and follows the curved surface of the concave portion. The photocathode 7 has a shape that is rotationally symmetric (axisymmetric) with respect to the tube axis A. For example, the incident surface (the surface opposite to the incident panel 2a (photocathode-forming surface 2a2)) and the exit surface (the surface opposite to the output panel 2b) of the photocathode 7 may also be formed into a spherical shape or a parabolic shape. The photocathode 7 is a so-called transmission-type photocathode, and releases electrons (photoelectrons) toward the fluorescent surface 8 (output panel 2b) according to the measurement light L incident from the incident panel 2a. Inside the container 2, a fluorescent surface 8 is provided on the inner surface of the output panel 2b. The fluorescent surface 8 releases an output image (fringe image) corresponding to the incident distribution of the electrons released by the photocathode 7 toward the outside according to the incidence of the electrons.

[0096] The mesh electrode 3 is an electrode for accelerating an electron beam having a shape in which the end portion on the photocathode 7 side of a cylindrical electrode is covered with a mesh. The central axis of the mesh electrode 3 substantially coincides with the tube axis A of the container 2. The mesh electrode 3 is disposed inside the container 2 adjacent to the photocathode 7. The mesh electrode 3 is disposed such that when a linear optical image in the Y-axis direction is incident on the incident panel 2a, the angle between the optical image and the mesh is approximately 45 degrees, that is, the mesh is at 45 degrees with respect to the X-axis (Y-axis). Thereby, moiré in the output image can be prevented. The interval of the mesh is set to, for example, 1,000 lines per inch.

[0097] The main focusing electrode 4 is an axially symmetric cylindrical electrode. The central axis of the main focusing electrode 4 substantially coincides with the tube axis A of the container 2. The main focusing electrode 4 is disposed inside the container 2 adjacent to the mesh electrode 3. The main focusing electrode 4 is disposed between the mesh electrode 3 and the aperture electrode 5.

[0098] The aperture electrode 5 is disposed adjacent to the main focusing electrode 4 on the side opposite to the side where the mesh electrode 3 is located with respect to the main focusing electrode 4. The aperture electrode 5 includes a cylindrical electrode 5a having a central axis substantially coinciding with the tube axis A, and a disc-shaped electrode 5b formed at the end portion on the fluorescent surface 8 side of the cylindrical electrode 5a. An aperture 5c (opening) for allowing electrons to pass through is provided at the center of the disc-shaped electrode 5b.

[0099] The mesh electrode 3, the main focusing electrode 4, and the aperture electrode 5 are a cylindrical electrode group (electron focusing system) that forms an axially symmetric electron lens for focusing the electrons released from the photoemissive surface 7 toward the fluorescent surface 8. To achieve such an electron focusing system, a prescribed negative potential (e.g., -3 kV) is applied to the photoemissive surface 7, a prescribed positive potential (e.g., +3 kV) is applied to the mesh electrode 3, a high positive potential is applied to the main focusing electrode 4, and a ground potential (0 V) is applied to the aperture electrode 5 and the fluorescent surface 8. As a result, a two-dimensional electron lens (a lens symmetric with respect to the tube axis A of the container 2) for focusing the electron beam accelerated in the Z-axis direction by the mesh electrode 3 onto the fluorescent surface 8 is formed between the mesh electrode 3 and the main focusing electrode 4 and between the main focusing electrode 4 and the aperture electrode 5. The magnitude of the potential applied to the main focusing electrode 4 can be adjusted so that the electron beam is optimally focused on the fluorescent surface 8. The inner diameters of the cylindrical portions of the mesh electrode 3, the main focusing electrode 4, and the aperture electrode 5 are, for example, 20 mm.

[0100] The one-dimensional electron lens 9 (electron lens) focuses the electrons passing through the aperture electrode 5 and the slit 12a of the following second slit member 12 in the X-axis direction. That is, the one-dimensional electron lens 9 is configured to focus the electrons on a plane (central plane CS) that includes the tube axis A and is perpendicular to the X-axis.

[0101] The scanning electrode 6 has a pair of plate-like electrodes (plate-like electrodes 6a, 6b) that face each other in the scanning direction (X-axis direction) along the output panel 2b. The plate-like electrodes 6a, 6b face each other in the X-axis direction with the central plane CS therebetween. As Figure 1 shown, as an example, the plate-like electrode 6a is arranged to be inclined with respect to the central plane CS so as to move away from the central plane CS as it goes from the incident panel 2a toward the output panel 2b. The plate-like electrode 6b is arranged parallel to the central plane CS. Since a scanning voltage is applied to the plate-like electrodes 6a, 6b, the electron group passing through the scanning electrode 6 is scanned in the X-axis direction.

[0102] Figure 2 is a schematic three-dimensional cross-sectional view showing the aperture electrode 5, the second slit member 12, the one-dimensional electron lens 9, and the first slit member 11. As Figure 1 and Figure 2 shown, the second slit member 12, the one-dimensional electron lens 9, and the first slit member 11 are sequentially arranged between the aperture electrode 5 and the scanning electrode 6.

[0103] As Figure 2As shown, the one-dimensional electron lens 9 has a plurality of (three in this embodiment) disk-shaped electrodes (first electrode 9a, second electrode 9b, and third electrode 9c). The first electrode 9a is disposed at the position closest to the incident panel 2a. The second electrode 9b is disposed at the position closest to the output panel 2b. The third electrode 9c is disposed between the first electrode 9a and the second electrode 9b separately from the first electrode 9a and the second electrode 9b. The first electrode 9a, the second electrode 9b, and the third electrode 9c are arranged to be spatially separated in the Z-axis direction (the direction along the tube axis A of the container 2) in a state along the output panel 2b.

[0104] An opening 10a penetrating in the Z-axis direction is provided in the first electrode 9a. When viewed from the Z-axis direction, the opening 10a has a horizontally long shape extending in the Y-axis direction (a direction perpendicular to the scanning direction) at a substantially central portion in the scanning direction (X-axis direction) of the first electrode 9a (i.e., a region including the center plane CS). Openings 10b and 10c identical to the opening 10a of the first electrode 9a are also provided in the second electrode 9b and the third electrode 9c. The centers of the openings 10a, 10b, and 10c are located on the tube axis A of the container 2.

[0105] From the viewpoint of enabling the one-dimensional electron lens 9 to function efficiently, the magnification of the length in the Y-axis direction of the openings 10a, 10b, and 10c with respect to the width in the X-axis direction is preferably 3 times or more. When the magnification of the openings 10a, 10b, and 10c is 3 times or more, it is possible to prevent an unnecessary electron lens action in the Y-axis direction due to the influence of the potentials at both ends in the length direction (Y-axis direction) of the openings 10a, 10b, and 10c. For example, the thickness (length in the Z-axis direction) of each of the first electrode 9a, the second electrode 9b, and the third electrode 9c is set to 3 mm, the opening width (width in the X-axis direction) of each of the openings 10a, 10b, and 10c is set to 4 mm, the length in the Y-axis direction of each of the openings 10a, 10b, and 10c is set to 25 mm, and the interval between the first electrode 9a, the second electrode 9b, and the third electrode 9c is set to 3 mm. In addition, both end portions in the Y-axis direction of the openings 10a, 10b, and 10c may be formed into Figure 2 the arc shape as shown, or may be formed into a straight line shape.

[0106] The first slit member 11 is disposed on the downstream side of the one-dimensional electron lens 9 in the advancing direction of electrons (the positive Z-axis direction). That is, the first slit member 11 is disposed between the one-dimensional electron lens 9 and the scanning electrode 6. In the present embodiment, as an example, the first slit member 11 is disposed in contact with the outer surface (the surface facing the fluorescent surface 8) of the second electrode 9b. That is, the first slit member 11 and the second electrode 9b are electrically connected and have the same potential. In addition, the first slit member 11 is formed in a disk shape. The first slit member 11 has a slit 11a (first slit) penetrating in the Z-axis direction. The center of the slit 11a in the scanning direction is located on the tube axis A in the same manner as the centers of the openings 10a, 10b, and 10c. The first slit member 11 is formed of a metal material such as stainless steel or aluminum, for example.

[0107] The second slit member 12 is disposed on the upstream side of the one-dimensional electron lens 9 in the advancing direction of electrons. That is, the first slit member 11 is disposed between the one-dimensional electron lens 9 and the incident panel 2a (more specifically, between the first electrode 9a and the aperture electrode 5). In the present embodiment, as an example, the second slit member 12 is disposed in contact with the outer surface (the surface facing the fluorescent surface 8) of the disk-shaped electrode 5b of the aperture electrode 5. That is, the second slit member 12 and the aperture electrode 5 are electrically connected and have the same potential. In addition, the second slit member 12 is formed in a disk shape in the same manner as the first slit member 11. The second slit member 12 has a slit 12a (second slit) penetrating in the Z-axis direction. The center of the slit 12a in the scanning direction is located on the tube axis A in the same manner as the centers of the openings 10a, 10b, and 10c. The second slit member 12 is formed of a metal material such as stainless steel or aluminum, for example.

[0108] The width of the slit 11a in the scanning direction (X-axis direction) is preferably 0.5 mm to 1.5 mm, and in the present embodiment, it is 0.8 mm as an example. The width of the slit 12a in the scanning direction (X-axis direction) is preferably 0.8 mm to 1.5 mm, and in the present embodiment, it is 1.2 mm as an example. That is, the widths of the slits 11a and 12a in the scanning direction (X-axis direction) are both smaller than the widths of the openings 10a, 10b, and 10c of the above-described plurality of electrodes (the first electrode 9a, the second electrode 9b, and the third electrode 9c) in the scanning direction. In addition, the width of the slit 11a in the scanning direction is preferably equal to or less than the width of the slit 12a in the scanning direction. In the present embodiment, the width of the slit 11a in the scanning direction is smaller than the width of the slit 12a in the scanning direction. The slit 11a functions to shield a part of the electron group that has passed through the one-dimensional electron lens 9 and to concentrate the range of the electron group directed toward the scanning electrode 6. The slit 12a functions to shield a part of the electron group that has passed through the aperture 5c of the aperture electrode 5 and to concentrate the range of the electron group directed toward the one-dimensional electron lens 9.

[0109] Next, referring again to Figure 1 the voltage control system of the streak tube 1A will be described. The first electrode 9a and the second electrode 9b are electrically connected to each other inside the container 2 and are also electrically connected to the aperture electrode 5. That is, the first electrode 9a, the second electrode 9b, and the aperture electrode 5 are at the same potential. In addition, the third electrode 9c is configured to be able to apply an arbitrary potential Vc from the outside.

[0110] The aperture electrode 5 and the fluorescent surface 8 are set to 0V by being applied with a ground potential (grounded). As a result, the potentials of the first electrode 9a and the second electrode 9b are set to 0V. At the same time, by dividing the voltage generated by the high-voltage power supply 13 using the voltage divider circuit 14, a potential of -3 kV is applied to the photocathode 7, and a potential of +3 kV is applied to the mesh electrode 3. In addition, the main focusing electrode voltage source 15 is connected to the main focusing electrode 4, and a high positive voltage is applied to the main focusing electrode 4 from the main focusing electrode voltage source 15. Furthermore, the third electrode voltage source 16 is connected to the third electrode 9c of the one-dimensional electron lens 9, and a preset potential Vc is applied to the third electrode 9c from the third electrode voltage source 16. The voltages output from the main focusing electrode voltage source 15 and the third electrode voltage source 16 can be adjusted.

[0111] A scanning voltage generation unit 17 is connected to the plate electrodes 6a and 6b of the scanning electrode 6. The scanning voltage generation unit 17 supplies scanning voltages Vd1(t) and Vd2(t) of opposite polarities (push-pull) to the plate electrodes 6a and 6b, respectively. The scanning voltages Vd1(t) and Vd2(t) are voltages that change with time and are set to voltages of opposite polarities to each other. In the present embodiment, the following setting signal generation unit 18 is configured to apply a positive potential to the plate electrode 6a and a negative potential to the plate electrode 6b at the start of the scan of the scanning electrode 6.

[0112] Figure 3 is a diagram showing an example of the scanning voltage applied to the scanning electrode 6. Figure 3 (A) is an example of the scanning voltages Vd1(t) and Vd2(t) in the synchronous scanning mode. As Figure 3 shown in (A) of, when the streak tube 1A operates in the synchronous scanning mode, high-frequency (for example, around 50 to 200 MHz) sinusoidal high-frequency voltages, that is, the scanning voltages Vd1(t) and Vd2(t), are applied to the plate electrodes 6a and 6b. As Figure 3As shown in (A), Vd1(t) and Vd2(t) are offset by half a wavelength (1 / 2 of wavelength w) and have opposite phases. For example, when observing light that is repeatedly generated at high speed, in the above synchronous scanning method, by synchronizing the scanning frequency with the repetition of the light to be measured, the fringe images can be overlapped (accumulated) at the same position on the fluorescent surface 8. Thus, even for weak luminescence phenomena, measurement can be performed with a high S / N ratio. In Figure 3 In the example of (A), the scanning voltages Vd1(t) and Vd2(t) are set by the following setting signal generation unit 18 so that the electron group matches the timing before and after the polarities of Vd1(t) and Vd2(t) are interchanged ( Figure 3 the region of the time interval s and the potential change amplitude h in (A)) passes through the scanning electrode 6. On the other hand, as Figure 3 shown in (B), when the streak tube 1A is operated in the single-scan mode, the scanning voltages Vd1(t) and Vd2(t) can also be controlled to change only once in a slanted shape.

[0113] A setting signal generation unit 18 is connected to the third electrode voltage source 16 and the scanning voltage generation unit 17. According to the signal from the setting signal generation unit 18, the voltage value output by the third electrode voltage source 16, the period, inclination, etc. of the scanning voltage generated by the scanning voltage generation unit 17 can be changed. That is, the setting signal generation unit 18 controls the potential applied to the scanning electrode 6 and the potential applied to at least one (the third electrode 9c) of the one-dimensional electron lenses 9 (multiple electrodes). The setting signal generation unit 18 sets the voltage value applied to the third electrode 9c of the one-dimensional electron lens 9 in conjunction with the change in the scanning voltage, and outputs parameters related to the change in the scanning voltage (for example, the frequency in the case of the above synchronous scanning method, the slope of the voltage that changes in a slanted shape in the case of the single-scan mode, etc.) and the set value indicating the voltage value applied to the third electrode 9c to the scanning voltage generation unit 17 and the third electrode voltage source 16, respectively.

[0114] The PIN photodiode 19 detects the incidence of the light L to be measured outside the container 2 and generates a trigger signal. The delay circuit 20 delays the trigger signal generated by the PIN photodiode 19 and outputs it to the scanning voltage generation unit 17. The scanning voltage generation unit 17 applies the scanning voltages Vd1(t), Vd2(t) to the scanning electrode 6 in accordance with the generation timing of the trigger signal. It is configured such that through the PIN photodiode 19 and the delay circuit 20, the scanning voltage can be applied to the scanning electrode 6 in accordance with the timing when the electron group generated on the photoelectric surface 7 passes through the scanning electrode 6 according to the incidence of the light L to be measured.

[0115] Next, an example of the operation of the streak tube 1A will be described. First, in a state where the plate electrodes 6a and 6b of the scanning electrode 6, the first electrode 9a and the second electrode 9b of the one-dimensional electron lens 9 are applied with a ground potential (Va = Vb = 0 kV) and the third electrode 9c is applied with a potential (in this embodiment, +700 V) within the range of +600 V to +1 kV, that is, the potential Vc, the measurement light L is imaged on the incident panel 2a via a half mirror, a slit plate, and an optical lens (not shown). Thus, a linear optical image along the Y-axis direction is incident on the photoelectric surface 7. At this time, by adjusting the output potential of the main focusing electrode voltage source 15 to a specified potential within the range of +6 kV to +10 kV (in this embodiment, +7 kV), a stationary linear optical image can be obtained on the fluorescent surface 8 in a focused state. Since the electron lens formed by the main focusing electrode 4 is an axially symmetric electron lens, the electron group is focused in a state where the focus is aligned in the direction perpendicular to the line direction of the linear optical image (scanning direction, X-axis direction), and is also focused in a state where the focus is aligned in its line direction (spatial direction, Y-axis direction).

[0116] Next, in the case where the scanning voltage is generated by the scanning voltage generation unit 17 and the electron group is scanned on the fluorescent surface 8, a luminance distribution (streak image) corresponding to the temporal change in the intensity of the linear optical image is obtained on the fluorescent surface 8. At this time, the setting signal generation unit 18 controls the scanning voltage generation unit 17 to apply an optimum scanning voltage corresponding to the scanning speed to the plate electrodes 6a and 6b.

[0117] Figure 4 It is a diagram schematically showing the operation of the one-dimensional electron lens in each of the comparative example and the embodiment. Figure 4 (A) of shows a cross-section of the XZ plane including the tube axis A of the one-dimensional electron lens 9 in the streak tube of the comparative example schematically. Figure 4 (B) of shows a cross-section of the XZ plane including the tube axis A of the one-dimensional electron lens 9 in the streak tube of the embodiment (that is, the streak tube having the structure of the streak tube 1A of this embodiment) schematically.

[0118] In Figure 4 In the comparative example shown in (A) of, a potential Vc lower than the potential Va of the first electrode 9a and the potential Vb of the second electrode 9b is applied to the third electrode 9c. For example, consider setting the potentials Va and Vb applied to the first electrode 9a and the second electrode 9b to the ground potential (0 V), and setting the potential applied to the third electrode 9c to a negative potential (for example, -350 V, -500 V, etc.).

[0119] In Figure 4Among them, the central orbit Tc represents the orbit (the orbit projected onto the XZ plane including the tube axis A) of the electrons that reach the one-dimensional electron lens 9 through the central plane CS along the tube axis A among the electron group generated on the photoelectric surface 7 according to the incidence of the measured light L. The peripheral orbit Tp represents the orbit (the orbit projected onto the XZ plane including the tube axis A) of the electrons that reach the one-dimensional electron lens 9 through the peripheral part separated from the central plane CS among the above electron group. The position Pc represents the position of the electrons at the moment t immediately after the electrons moving along the central orbit Tc pass through the opening 10b of the one-dimensional electron lens 9 (the second electrode 9b). The position Pp represents the position of the electrons at the moment t of the electrons moving along the peripheral orbit Tp.

[0120] In Figure 4 In the comparative example shown in (A) of

[0121] In contrast, in Figure 4In the embodiment shown in (B) above, a positive potential Vc higher than the potentials Va and Vb applied to the first electrode 9a and the second electrode 9b is applied to the third electrode 9c as described above. Therefore, an electron acceleration region is formed near the electron incident side of the opening 10c of the third electrode 9c, and an electron deceleration region is formed near the electron emission side of the opening 10c. Thus, an external force F having a component (acceleration component) in the same direction as the advancing direction of the electrons (the direction from the photocathode surface 7 toward the fluorescent surface 8) acts particularly on the electrons passing through the region between the first electrode 9a and the third electrode 9c due to the electric field generated by the potential difference between the potentials Va and Vb and the potential Vc. In this way, when the electron group incident on the one-dimensional electron lens 9 is first made to enter the electron acceleration region (i.e., the region formed near the electron incident side of the opening 10c), it is possible to suppress the orbit of the electrons (especially the orbit far from the central plane CS of the one-dimensional electron lens 9) from approaching the central plane CS of the one-dimensional electron lens 9 excessively. Therefore, the velocity difference between the electrons can be effectively reduced. In addition, the electron group can pass through the electron deceleration region near the electron emission side of the opening 10c in a shorter time in a state where the velocity is increased compared to the comparative example ( Figure 4 of (A)). That is, compared with the comparative example, the influence of the electron deceleration region, which is a factor that increases the velocity difference between the electrons, can be reduced. By the action described above, according to the embodiment, the velocity difference of the electron group passing through the one-dimensional electron lens 9 can be reduced. Furthermore, compared with the electrons moving along the central orbit Tc along the central plane CS, the electrons moving along the peripheral orbit Tp in the peripheral part far from the central plane CS are more easily affected (accelerated) by the above external force F. Therefore, the velocity difference between the electrons moving along the central orbit Tc and the electrons moving along the peripheral orbit Tp becomes smaller. As a result, according to the embodiment, since the arrival time difference of the electron group generated simultaneously on the photocathode surface 7 to the fluorescent surface 8 can be shortened compared with the comparative example, a higher time resolution can be obtained compared with the comparative example.

[0122] In addition, compared with the one-dimensional electron lens 9, the electron group passing through the peripheral orbit Tp also passes through a path that detours with respect to the electron group passing through the central orbit Tc (i.e., a path longer than the path along the central orbit Tc) in the electron focusing system in front. Therefore, at the moment of incidence on the one-dimensional electron lens 9, the electron group passing through the peripheral orbit Tp may be slightly delayed with respect to the electron group passing through the central orbit Tc. In the streak tube 1A, by adopting a structure in which a potential Vc higher than the potentials Va and Vb applied to the first electrode 9a and the second electrode 9b is applied to the third electrode 9c, the delay of the electron group passing through the peripheral orbit Tp with respect to the electron group passing through the central orbit Tc is appropriately corrected. That is, the electron group passing through the peripheral orbit Tp can be made to appropriately keep up with the electron group passing through the central orbit Tc. As a result, the arrival time difference of the electron groups simultaneously generated on the photocathode 7 to the fluorescent screen 8 can be reduced, and high time resolution of the streak tube 1A can be achieved.

[0123] [Function and effect of the first embodiment]

[0124] As described above, in the streak tube 1A, a potential Vc higher than the potential Va of the first electrode 9a and the potential Vb of the second electrode 9b is applied to the third electrode 9c disposed inside the first electrode 9a and the second electrode 9b located at both ends among the plurality of electrodes forming the one-dimensional electron lens 9 (in this embodiment, as an example, the first electrode 9a, the second electrode 9b, and the third electrode 9c). Here, if a potential lower than the first electrode 9a and the second electrode 9b is applied to the third electrode 9c as in the above comparative example, an electron deceleration region that decelerates the speed of electrons is formed near the electron incident side of the opening 10c of the third electrode 9c (as shown in (A) of Figure 4 , a region where an external force F having a component in the direction opposite to the advancing direction of the electrons acts). In contrast, according to the structure of this embodiment in which a potential Vc higher than the first electrode 9a and the second electrode 9b is applied to the third electrode 9c, as shown in (B) of Figure 4 , the formation of the above-described electron deceleration region can be suppressed, and the electrons near the electron incident side of the opening 10c of the third electrode 9c can be accelerated. Further, among the electron groups passing through the one-dimensional electron lens 9, the electrons passing through the orbits farther from the central plane CS of the one-dimensional electron lens 9 are subjected to a stronger acceleration effect caused by the potential difference. As a result, the velocity difference (i.e., the arrival time difference to the scanning electrode 6) between the electrons in the electron group after passing through the one-dimensional electron lens 9 generated by the electron group passing through the one-dimensional electron lens 9 can be reduced. Therefore, according to the streak tube 1A, the time resolution can be effectively improved.

[0125] In addition, the first electrode 9a and the second electrode 9b have the same potential. According to the above structure, the time resolution can be improved more effectively. More specifically, by setting the first electrode 9a and the second electrode 9b to the same potential, the electron lens formed around the third electrode 9c (i.e., the region where the electron lens effect is generated by the electric field formed by the third electrode 9c) can be localized (i.e., formed near the third electrode 9c). As a result, compared with the electrons passing through the vicinity of the central plane CS of the one-dimensional electron lens 9, the electrons passing through the orbits farther from the central plane CS are subjected to a stronger acceleration effect caused by the potential difference. Consequently, since the velocity difference (i.e., the arrival time difference at the scanning electrode 6) between the electrons passing through the vicinity of the central plane CS and the electrons passing through the orbits farther from the central plane CS can be reduced more effectively, the above-described time resolution improvement effect can be enhanced.

[0126] In addition, the first slit member 11 and the second electrode 9b have the same potential. According to the above structure, the time resolution can be improved more effectively. If the second electrode 9b and the first slit member 11 are set to different potentials, an unnecessary electron lens (i.e., a region where the electron lens effect is generated between the one-dimensional electron lens 9 and the scanning electrode 6 separately from the electron lens formed by the one-dimensional electron lens 9) that coexists with the electric field formed by the scanning electrode 6 may be formed near the slit 11a (opening) of the first slit member 11. This unnecessary electron lens affects the time resolution characteristics. In contrast, by setting the second electrode 9b and the first slit member 11 to the same potential, the first slit member 11 can be reliably separated from the electric field formed by the scanning electrode 6. Therefore, the formation of the above-described unnecessary electron lens can be prevented. As a result, the time resolution characteristics can be stabilized.

[0127] In addition, the second slit member 12 has the same potential as at least one of (both in this embodiment) the aperture electrode 5 and the first electrode 9a. With the above structure, the time resolution can be more effectively improved. More specifically, when the second slit member 12 and the first electrode 9a have the same potential, the electron lens formed around the third electrode 9c can be effectively localised, and thus, the same effect as in the case where the first electrode 9a and the second electrode 9b have the same potential can be promoted. In addition, when the second slit member 12 and the aperture electrode 5 have the same potential, although the localisation of the electron lens formed around the third electrode 9c is slightly alleviated, instead, an electron acceleration region may be formed near the opening on the electron incident side of the first electrode 9a. Thus, according to the former structure (the structure in which the second slit member 12 and the first electrode 9a have the same potential), the improvement of the time resolution can be achieved by the efficient acceleration in a narrow region (the localised region around the third electrode 9c). On the other hand, according to the latter structure (the structure in which the second slit member 12 and the aperture electrode 5 have the same potential), the improvement of the time resolution can be achieved by the efficient acceleration in a wide region. In addition, although the effect of the former structure is slightly alleviated by the latter structure as described above, when both structures are provided, the effects of the former structure and the latter structure can be obtained in a balanced manner.

[0128] Next, as another effect of the first embodiment, the effect of the photocathode 7 of this embodiment will be described. Figure 5 (A) of is a diagram schematically showing the structure inside the container 2 of the streak tube 501 of the comparative example from the perspective of the positive X-axis direction. Figure 5 (B) of is a diagram schematically showing the structure inside the container 2 of the embodiment (the streak tube 1A of the first embodiment) from the perspective of the positive X-axis direction.

[0129] The streak tube 501 is different from the streak tube 1A having the curved photocathode 7 protruding toward the incident panel 2a in that it has a planar (flat plate-like) photocathode 507 substantially parallel to the XY plane.

[0130] In Figure 5In (A) and (B) thereof, the measured lights L1, L2, and L3 are representative components of the measured light L (a linear optical image extending in the Y-axis direction) that is incident on different Y coordinates of the incident panel 2a. By the collision of the measured lights L1, L2, and L3 with the photoelectric surfaces 7 and 507, an electron group is released toward the output panel 2b. The electron beams B1, B2, and B3 respectively represent the general profiles of the path groups of the electrons generated on the photoelectric surfaces 7 and 507 according to the incidence of the measured lights L1, L2, and L3 and reaching the fluorescent surface 8 from the photoelectric surfaces 7 and 507. For simplicity of explanation, the X-axis coordinates of the measured lights L1, L2, and L3 and the electron beams B1, B2, and B3 are not considered here.

[0131] As Figure 5 shown, since the electron group generated by the measured lights L1, L2, and L3 needs to pass through the aperture 5c of the disk-shaped electrode 5b of the aperture electrode 5 during the period from the photoelectric surfaces 7 and 507 toward the fluorescent surface 8, the electron beams B1, B2, and B3 cross near the center of the container 2. That is, the order relationship of the Y coordinates of the electron group generated by the measured lights L1, L2, and L3 is interchanged during the period from the photoelectric surfaces 7 and 507 toward the fluorescent surface 8.

[0132] Therefore, in the case where the photoelectric surface 507 is a planar shape parallel to the XY plane as in the Figure 5 image intensifier tube 501 shown in (A), the paths of the electron group generated by the measured lights L1 and L3 that are incident separately in the Y direction from the tube axis A are longer than the measured light L2 that is incident near the tube axis A. In contrast, by making the photoelectric surface 7 a curved surface shape protruding toward the incident panel 2a as in the Figure 5 image intensifier tube 1A shown in (B), the difference in the path lengths of the above electron group to the fluorescent surface 8 can be reduced.

[0133] Figure 6 (A) is an enlarged view of a part of the fluorescent surface 8 including the Figure 5 image intensifier tube 501 shown in (A) of Figure 6 and (B) is an enlarged view of a part of the fluorescent surface 8 including the Figure 5 image intensifier tube 1A shown in (B) of

[0134] Figure 6 The focus line FL shown in (A) and (B) is a curve connecting the points (focus points) where the spread of each electron beam B1, B2, and B3 is minimized. As Figure 6As shown, when the focus is adjusted so that the spread on the fluorescent surface 8 of the electron beam B2 with the shortest path along the tube axis A becomes minimum, the focal points of the electron beams B1 and B3 move away from the fluorescent surface 8. That is, since the path lengths of the electron beams B1 and B3 and the path length of the electron beam B2 are different from each other, when the fluorescent surface 8 is adjusted to be located at the focal point of the electron beam B2, the focal points of the electron beams B1 and B3 move away from the fluorescent surface 8. As a result, as shown in (A) of Figure 6 in the streak tube 501 of the comparative example, the spread width W on the fluorescent surface 8 of the electron beams B1 and B3 in the peripheral portion away from the center portion becomes large, and the spatial resolution may be impaired.

[0135] On the other hand, in the case of adopting a photocathode surface 7 having a curved surface protruding toward the incident panel 2a as in Figure 6 (B) of the embodiment (the streak tube 1A of the first embodiment), the difference between the path lengths of the electron beams B1 and B3 and the path length of the electron beam B2 can be reduced as compared with the comparative example. That is, Figure 6 the curvature of the focal line FL of the embodiment shown in (B) of Figure 6 is smaller (gentler) than the curvature of the focal line FL of the comparative example shown in (A) of

[0136] As a result, according to the embodiment, the spread width W of the electron beams B1 and B3 on the fluorescent surface 8 can be suppressed as compared with the comparative example, and the spatial resolution can be improved. In other words, in the forward direction of the electrons (i.e., the direction from the incident panel 2a toward the output panel 2b), the distance difference between the focal point of the electrons (i.e., the electron beam B2) released from the position near the center of the photocathode surface 7 toward the output panel 2b and the focal points of the electrons (i.e., the electron beams B1 and B3) released from the position away from the center of the photocathode surface 7 toward the output panel 2b can be reduced. As a result, the resolution (spatial resolution) in the spatial direction (Y-axis direction) due to the difference in the electron release positions (i.e., the incident positions of the measured light L on the photocathode surface 7) on the photocathode surface 7 can be improved.

[0137] [Modification Example of the First Embodiment]

[0138] The one-dimensional electron lens 9 may also be composed of more than four electrodes. That is, between the first electrode 9a and the second electrode 9b, two or more electrodes including the above-mentioned third electrode 9c may also be arranged.

[0139] Figure 7 FIG. is a diagram schematically showing a modified one-dimensional electron lens 709. As Figure 7 shown, the one-dimensional electron lens 709 has a first electrode 9a arranged at the position closest to the incident panel 2a, a second electrode 9b arranged at the position closest to the output panel 2b, and a third electrode 9c arranged between the first electrode 9a and the second electrode 9b separately from the first electrode 9a and the second electrode 9b, and also has other electrodes 9d arranged between the second electrode 9b and the third electrode 9c separately from the second electrode 9b and the third electrode 9c.

[0140] Potentials Va, Vb, Vc, and Vd are applied to the first electrode 9a, the second electrode 9b, the third electrode 9c, and the other electrodes 9d, respectively. At this time, it is only necessary to satisfy "Vc > Va" and "Vc > Vb". For example, as the magnitude relationship of the applied potentials, "Vd > Vc > Va = Vb", "Vc = Vd > Va = Vb", "Vc > Va = Vb = Vd", "Vc > Va = Vb > Vd", etc. can be taken. In addition, two or more of the other electrodes 9d may also be arranged. In addition, the other electrodes 9d may also function as electrodes to which a potential Vd higher than the potentials Va and Vb applied to the first electrode 9a and the second electrode 9b is applied (that is, electrodes that play the same role as the third electrode 9c). That is, the one-dimensional electron lens may also have a plurality of electrodes (third electrodes) that satisfy the above technical requirements of the potential. In addition, as Figure 7 shown, the widths (lengths in the Z-axis direction) of the respective electrodes constituting the one-dimensional electron lens may also be different from each other. The opening widths (widths in the X-axis direction) of the opening portions 10a to 10d of the respective electrodes may also be different from each other.

[0141] [Second Embodiment]

[0142] Refer to Figures 8 to 13 , and the streak tube 1B of the second embodiment will be described. Figure 8 FIG. is a cross-sectional view along a plane including the tube axis A of the streak tube 1B and perpendicular to the deflection plates (plate-like electrodes 6a, 6b) of the scanning electrode 6. Figure 9 FIG. is a schematic three-dimensional cross-sectional view showing the aperture electrode 5, the second slit member 12B, the one-dimensional electron lens 9, and the first slit member 11B in the streak tube 1B.

[0143] As Figure 8 and Figure 9As shown, the first slit member 11B and the second slit member 12B of the streak tube 1B differ from the first slit member 11 and the second slit member 12 of the streak tube 1A in the first embodiment in the following points.

[0144] In the first slit member 11B, the center of the slit 11a in the scanning direction (X-axis direction) is arranged at a position separated from the center plane CS (a plane passing through the center of the one-dimensional electron lens 9 and orthogonal to the scanning direction) on the side where the plate electrode 6a (the electrode to which a positive potential is applied at the start of scanning) is located. That is, the first slit member 11B is arranged at a position slightly slid (parallel moved) in the positive X-axis direction compared to the first slit member 11 of the streak tube 1A. In the present embodiment, as an example, the center of the slit 11a of the first slit member 11B is arranged at a position separated (eccentric) from the center plane CS by a distance within the range of 0.1 mm to 0.7 mm in the positive X-axis direction (0.3 mm in the present embodiment).

[0145] In the second slit member 12B, the center of the slit 12a in the scanning direction (X-axis direction) is arranged at a position separated from the center plane CS on the side where the plate electrode 6b (the electrode to which a negative potential is applied at the start of scanning) is located. That is, the second slit member 12B is arranged at a position slightly slid (parallel moved) in the negative X-axis direction compared to the second slit member 12 of the streak tube 1A. In the present embodiment, as an example, the center of the slit 12a of the second slit member 12B is arranged at a position separated (eccentric) from the center plane CS by a distance within the range of 0.1 mm to 0.5 mm in the negative X-axis direction (0.2 mm in the present embodiment).

[0146] Here, in the region between the plate electrodes 6a and 6b of the scanning electrode 6, the region on the electron incident side closer to the plate electrode 6b than the center plane CS becomes a deceleration region where electrons are easily decelerated because a negative electric field is generated at the start of scanning. On the other hand, in the region between the plate electrodes 6a and 6b of the scanning electrode 6, the region on the electron incident side closer to the plate electrode 6a than the center plane CS becomes an acceleration region where electrons are easily accelerated because a positive electric field is generated at the start of scanning.

[0147] By providing the first slit member 11B configured to be eccentric in the positive X-axis direction as described above, it is possible to shield a part of the electron group heading toward the deceleration region among the electron groups that have passed through the one-dimensional electron lens 9 (i.e., electrons passing through the peripheral portion that is significantly separated toward the negative X-axis side compared to the central plane CS), thereby reducing the number of electrons entering the deceleration region. As a result, it is possible to suppress the deviation in the velocity and the advancing direction (angle) of the electron group entering between the plate electrodes 6a and 6b (i.e., the deviation in the arrival time at the fluorescent surface 8). Consequently, it is possible to suppress the spatial spread in the scanning direction (time direction) of the electron group reaching the fluorescent surface 8 and improve the time resolution. More specifically, when the electron group passes through the region on the electron incident side of the scanning electrode 6, the electrons passing through the region near the plate electrode 6a (acceleration region) that is applied a positive potential at the start of scanning are accelerated in the direction from the incident panel 2a toward the output panel 2b due to the electric field caused by the positive potential. On the other hand, the electrons passing through the region near the plate electrode 6b (deceleration region) that is applied a negative potential at the start of scanning are decelerated in the direction from the output panel 2b toward the incident panel 2a. The difference in the acceleration and deceleration effects between the electrons incident on the acceleration region and those incident on the deceleration region may cause a deviation in the position where the electrons reach the fluorescent surface 8. According to the above-described first slit member 11B, it is possible to shield the electrons in the electron group passing through the one-dimensional electron lens 9 that are to be incident on the deceleration region near the plate electrode 6b of the scanning electrode 6. Thereby, it is possible to reduce the deviation in the arrival position of the electrons reaching the fluorescent surface 8 and improve the time resolution.

[0148] In addition, by providing the second slit member 12B configured to be eccentric in the negative X-axis direction as described above, a part of the electrons passing through the peripheral portion that is significantly separated toward the positive X-axis side compared to the central plane CS among the electron group incident on the one-dimensional electron lens 9 can be blocked. As a result, the deviation in the velocity and the advancing direction (angle) of the electron group entering between the plate-like electrodes 6a and 6b (i.e., the deviation in the arrival position on the fluorescent surface 8) can be suppressed. As a result, the spatial spread of the scanning direction (time direction) of the electron group reaching the fluorescent surface 8 can be suppressed, and the time resolution can be improved. In addition, compared with the electrons passing through the central path near the central plane CS, the traveling distance of the electrons passing through the peripheral path separated from the central plane CS of the one-dimensional electron lens 9 is longer. That is, the path length of the peripheral path is greater than the path length of the central path. Therefore, compared with the electrons passing through the central path near the central plane CS, a delay may occur in the time when the electrons passing through the peripheral path separated from the central plane CS reach the fluorescent surface 8. As a result, the arrival position of the electrons on the fluorescent surface 8 may deviate. According to the above structure, by the second slit member 12, a part of the electrons passing through the peripheral path among the electron group to be incident on the one-dimensional electron lens 9 can be blocked in front of the one-dimensional electron lens 9. As a result, the deviation in the arrival position of the electrons reaching the fluorescent surface 8 can be reduced, and the time resolution can be improved.

[0149] Furthermore, by combining the above-described structure C1 of the streak tube 1A (i.e., the structure in which a potential Vc higher than the potential Va of the first electrode 9a and the potential Vb of the second electrode 9b is applied to the third electrode 9c) and the structure C2 of the streak tube 1B (i.e., the structure C2 of the first slit member 11B and the second slit member 12B), the improvement of the time resolution can be achieved more effectively. More specifically, in the case of adopting the above-described structure C1, compared with the case of adopting the conventional structure in which the potential Vc is lower than the potentials Va and Vb, the electron group passing through the one-dimensional electron lens 9 is accelerated, and thus, the condensing effect of the one-dimensional electron lens 9 may be reduced. That is, in the above-described structure C1, compared with the above-described conventional structure, the orbit of the electron group passing through the one-dimensional electron lens 9 may be easily expanded. Therefore, by blocking a part of the electron group passing through the peripheral portion separated from the central plane CS by the above-described structure C2, the improvement of the time resolution can be appropriately achieved. That is, by reducing the velocity difference of the electron group passing through the one-dimensional electron lens 9 by the above-described structure C1 and blocking the electron group in the peripheral portion of the electron group that is more easily expanded by the above-described structure C1 than in the past by the above-described structure C2, high time resolution can be appropriately achieved.

[0150] Next, referring to Figures 10 to 12 the effects of the streak tube 1B will be supplemented. Figure 10 is a diagram schematically showing the results of a time resolution test of a streak tube of a comparative example (hereinafter, simply referred to as "comparative example"). Figure 11This is a diagram schematically showing the results of the time resolution test of the streak tube of the first embodiment (hereinafter simply referred to as the "first embodiment"). Figure 12 This is a diagram schematically showing the results of the time resolution analysis (simulation) of the streak tube of the second embodiment (hereinafter simply referred to as the "second embodiment").

[0151] Figure 10 The comparative example shown does not have both of the above-described structures C1 and C2. That is, the comparative example has the same first slit member 11 and second slit member 12 as the streak tube 1A of the first embodiment (that is, the slit members configured such that the centers of the slits 11a and 12a overlap the tube axis A). In addition, in the comparative example, "Va = Vb = 0V (GND)" is applied to the first electrode 9a and the second electrode 9b, and a potential Vc (= -500V) lower than the potentials Va and Vb is applied to the third electrode 9c.

[0152] Figure 11 The first embodiment shown has the above-described structure C2 but does not have structure C1. That is, the first embodiment has the same first slit member 11B and second slit member 12B as the streak tube 1B of the second embodiment. In addition, in the first embodiment, as in the comparative example, "Va = Vb = 0V (GND)" is applied to the first electrode 9a and the second electrode 9b, and a potential Vc (= -500V) smaller than the potentials Va and Vb is applied to the third electrode 9c.

[0153] Figure 12 The second embodiment shown has both of the above-described structures C1 and C2. That is, the second embodiment has the same first slit member 11B and second slit member 12B as the streak tube 1B of the second embodiment. In addition, in the second embodiment, "Va = Vb = 0V (GND)" is applied to the first electrode 9a and the second electrode 9b, and a potential Vc (= +700V) higher than the potentials Va and Vb is applied to the third electrode 9c.

[0154] In addition, measurement conditions other than the above (for example, the type of the photocathode 7, the type of the measured light L, etc.) are set to be the same in the comparative example, the first embodiment, and the second embodiment.

[0155] (Comparative Example)

[0156] Refer to Figure 10 and the comparative example will be described. In Figure 10Among them, the path curve R1 is the path curve of the electrons incident on the scanning electrode 6 (i.e., the electrons entering the space between the plate electrodes 6a and 6b) that pass through the peripheral path farthest from the center plane CS in the positive X-axis direction. The path curve R2 is the path curve of the electrons incident on the scanning electrode 6 that pass through the peripheral path farthest from the center plane CS in the negative X-axis direction. That is, the path curve R1 is the path passing near the upper end of the slit 12a of the second slit member 12, and the path curve R2 is the path passing near the lower end of the slit 12a.

[0157] In the space between the plate electrodes 6a and 6b of the scanning electrode 6, the region closer to the plate electrode 6a than the center plane CS is denoted as the acceleration region AF, and the region closer to the plate electrode 6b than the center plane CS is denoted as the deceleration region DF. At the start of scanning, the plate electrode 6a is applied with a positive potential, and the plate electrode 6b is applied with a negative potential. Due to the effect of the resulting electric field, the electrons incident on the acceleration region AF tend to be accelerated in the direction of the output panel 2b, and the electrons incident on the deceleration region DF tend to be decelerated in the direction of the incident panel 2a. From the viewpoint of improving the time resolution, it is preferable to reduce the difference in the arrival time at the fluorescent surface 8 caused by the difference in the paths of the electron groups generated simultaneously on the photocathode surface 7. For this purpose, it is preferable to increase the proportion of electrons entering the acceleration region AF as much as possible. In other words, it is preferable to minimize the electrons (the electrons entering the deceleration region DF) whose speed difference from the electrons entering the acceleration region AF becomes large.

[0158] As Figure 10 shown, the electrons passing through the path curve R1 enter the acceleration region AF from the beginning. In contrast, the electrons passing through the path curve R2 are incident on the deceleration region DF from the beginning. Therefore, the distribution of the electron group immediately after entering the space inside the scanning electrode 6 is roughly the distribution across the acceleration region AF and the deceleration region DF as shown by the electron group EG1. Since the electron group incident on the deceleration region DF is relatively decelerated with respect to the acceleration region AF, the subsequent distribution of the electron group is the distribution extending in the Z direction as shown by the electron group EG2. That is, the speed difference (the expansion in the Z-axis direction) of the electron group becomes large. This speed difference of the electron group is revealed as the shift of the X coordinate at the time of electron collision with the fluorescent surface 8. Therefore, from the viewpoint of realizing the improvement of the time resolution of the streak tube, it is preferable to increase the proportion of electrons entering the acceleration region AF as much as possible (that is, to minimize the proportion of electrons entering the deceleration region DF). It can be said that from this viewpoint, there is room for improvement in the comparative example.

[0159] In Figure 10 the right end depicts the broken line curve LC representing the distribution of the X coordinates of the collision points of the electrons colliding with the fluorescent surface 8. The smaller the variance of the broken line curve LC in the X-axis direction, the higher the time resolution of the streak tube.Figure 10 The time resolution TR1 analyzed in the shown comparative example is approximately 600 fs.

[0160] (First Embodiment)

[0161] Next, with reference to Figure 11 , the first embodiment will be described. As Figure 11 shown, in the first embodiment, the path curve R1 of the electrons passing near the upper end of the slit 12a in the comparative example is shielded by the second slit member 12B eccentric in the negative X-axis direction. In addition, the path curve R2 of the electrons passing near the lower end of the slit 11a of the first slit member 11 in the comparative example is shielded by the lower end of the slit 11a of the first slit member 11B eccentric in the positive X-axis direction. As a result, among the electrons incident on the scanning electrode 6, the path curve R3 of the electrons passing through the peripheral path farthest from the center plane CS in the positive X-axis direction passes inside closer to the center plane CS than the path curve R1 of the comparative example. In addition, among the electrons incident on the scanning electrode 6, the path curve R4 of the electrons passing through the peripheral path farthest from the center plane CS in the negative X-axis direction passes inside closer to the center plane CS than the path curve R2 of the comparative example.

[0162] That is, in the first embodiment, the electrons passing through the peripheral portion separated from the center plane CS in the X-axis direction are effectively shielded by the first slit member 11B and the second slit member 12B. As a result, the distribution width of the electron group in the X-axis direction passing through the scanning electrode 6 becomes smaller. More specifically, as Figure 11 shown, the width of the electron group EG1 in the X-axis direction in the first embodiment becomes smaller than the width of the electron group EG1 in the X-axis direction in the Figure 10 shown comparative example. In addition, in the first embodiment, the proportion of the electrons entering the deceleration region DF is smaller than that in the comparative example. That is, the electron group incident on the scanning electrode 6 is concentrated by the first slit member 11B and the second slit member 12B and is effectively guided to the acceleration region AF. Therefore, the distribution of the subsequent electron group EG2 also does not become a shape extending along the Z-axis direction as much as that in the Figure 10 shown comparative example, and the variance of the X coordinate of the collision position of the electrons colliding with the fluorescent surface 8 is suppressed to be small. As a result, in the first embodiment, a higher time resolution TR2 (≈ about 500 fs) is obtained as the analysis result than in the comparative example. In addition, Figure 11 The dashed line shown in the illustrated area of the broken line curve LC represents the position of the broken line curve LC of the comparative example ( Figure 10 ).

[0163] (Second Embodiment)

[0164] Next, with reference to Figure 12, the second embodiment will be described. As described above, on the basis of the first embodiment, the second embodiment further includes a structure C1 in which the potential Vc applied to the third electrode 9c is higher than the potential Va applied to the first electrode 9a and the potential Vb applied to the second electrode 9b. Therefore, in the second embodiment, compared with the comparative example and the first embodiment, although the electron group passing through the one-dimensional electron lens 9 may be easily expanded, this expansion of the electron group can be effectively suppressed by the above-described structure C2 (the first slit member 11B and the second slit member 12B), and the effects of both the above-described structures C1 and C2 (that is, the reduction of the deviation in the arrival time of the electron group at the fluorescent surface 8) can be obtained. As a result, in the second embodiment, a higher time resolution TR3 (= about 350 fs) is obtained as an analysis result than in the first embodiment. In addition, Figure 12 The dotted line shown in the illustrated area of the broken line curve LC of Figure 10 indicates the position of the broken line curve LC of the comparative example (

[0165] As Figures 10 to 12 shown, it was confirmed from the results of the comparative example and the first embodiment that even when only the structure C2 among the above-described structures C1 and C2 is adopted, an improvement effect in time resolution is also obtained. Furthermore, it was confirmed from the results of the first embodiment and the second embodiment that by adopting the above-described structure C1, the time resolution can be improved.

[0166] Figure 13 represents the results of performing multiple measurements on the above-described first embodiment and second embodiment respectively under conditions different from the above-described Figures 10 to 12 time resolution analysis (such as the type of the photoemissive surface 7, etc.). It was also confirmed from the results Figure 13 shown that an improvement effect in time resolution is obtained when both the structures C1 and C2 are adopted compared with the case where only the above-described structure C2 is adopted.

[0167] [Modification Example]

[0168] As described above, some embodiments and some modification examples of the present disclosure have been described, but the present disclosure is not limited to the structures shown in the above-described respective embodiments and respective modification examples. The materials and shapes of the respective structures are not limited to the above-described specific materials and shapes, and various materials and shapes other than the above can be adopted. In addition, a part of the structures included in the above-described respective embodiments and respective modification examples can be appropriately omitted or changed, or can be arbitrarily combined.

[0169] For example, the arrangement and shape of the scanning electrode 6 are not limited to the above-described embodiment (refer to Figure 1 etc.). Refer to Figure 14 to describe some modification examples of the scanning electrode 6. In addition, in Figure 14 , the illustration of the slit member described in the above-described embodiment is omitted.

[0170] Figure 14 (A) is a diagram schematically showing the streak tube 1C having the scanning electrode 6 of the first modification. As Figure 14 shown in (A), the scanning electrode 6 (plate electrodes 6a, 6b) may be symmetrically arranged with respect to the central plane CS of the one-dimensional electron lens 9.

[0171] Figure 14 (B) is a diagram schematically showing the streak tube 1D having the scanning electrode 6 of the second modification. As Figure 14 shown in (B), the distance d1 between the end 6a1 closest to the incident panel 2a on the inner side of the plate electrode 6a (the electrode to which a positive potential is applied at the start of scanning in the scanning electrode 6) opposite to the central plane CS and the central plane CS may also be shorter than the distance d2 between the end 6b1 closest to the incident panel 2a on the inner side of the plate electrode 6b (the electrode to which a negative potential is applied at the start of scanning in the scanning electrode 6) opposite to the central plane CS. In Figure 14 the example of (B), the scanning electrode 6 of the streak tube 1D is arranged at a position where the scanning electrode 6 of the streak tube 1C is slightly translated in parallel in the negative X-axis direction. According to the above structure, the center in the X-axis direction of the incident-side opening of the scanning electrode 6 can be shifted downward with respect to the central plane CS (in the direction closer to the plate electrode 6b to which a negative potential is applied at the start of scanning). According to this structure, the electron group after passing through the one-dimensional electron lens 9 can be appropriately guided to the region closer to the plate electrode 6a to which a positive potential is applied at the start of scanning (that is, the acceleration region AF closer to the plate electrode 6a than the center position in the X-axis direction of the incident-side opening of the scanning electrode 6). In addition, the electrons incident on the region closer to the plate electrode 6b to which a negative potential is applied at the start of scanning (that is, the deceleration region DF closer to the plate electrode 6b than the center position in the X-axis direction of the incident-side opening of the scanning electrode 6) can be reduced. As a result, the deviation in the arrival positions of the electrons at the fluorescent surface 8 is reduced. As a result, the time resolution can be more effectively improved.

[0172] In addition, in the streak tube of the present disclosure, the pair of plate electrodes in the scanning electrode may also be traveling-wave electrodes configured such that the applied potential changes synchronously with the traveling speed of the electrons between the pair of plate electrodes. Figure 15 is a diagram schematically showing the streak tube 1E having the scanning electrode 6E of the third modification having such a structure. As Figure 15 shown, the scanning electrode 6E has plate electrodes 6Ea (first plate electrode) and 6Eb (second plate electrode) formed to be zigzag-refolded in such a manner that the voltage propagates synchronously with the traveling electrons.

[0173] In the scanning electrode 6E, the traveling speed of electrons in the scanning electrode 6E is matched, and a potential is applied so as to propagate from the end portion 61 closest to the incident panel 2a of the plate-like electrodes 6Ea and 6Eb toward the end portion 62 closest to the output panel 2b. According to the above structure, since more precise scanning control of the electron group in the scanning electrode 6E can be achieved, the time resolution can be more effectively improved.

[0174] In addition, in the above-described embodiment, the main focusing electrode 4 formed in a cylindrically symmetric cylindrical shape has been described, but the shape of the main focusing electrode is not limited to the above. For example, the main focusing electrode may also have a shape that converges on the exit side (the side where the aperture electrode 5 is located), similar to the aperture electrode 5. Figure 16 FIG. is a diagram schematically showing a streak tube 1F including a modified main focusing electrode 4F having such a shape. The main focusing electrode 4F includes a cylindrical electrode 4Fa having a central axis substantially coinciding with the tube axis A, and a disk-shaped electrode 4Fb formed at an end portion on the fluorescent surface 8 side of the cylindrical electrode 4Fa. An aperture 4Fc (opening) for allowing electrons to pass through is provided at the center of the disk-shaped electrode 4Fb. According to the above structure, when the electron group passes through the main focusing electrode 4F, the disk-shaped electrode 4Fb shields electrons passing through a path separated from the tube axis A, thereby appropriately suppressing the spread of the electron group.

[0175] In addition, other than the above, various modifications can also be made. For example, the voltage control of the plate-like electrode 6a and the plate-like electrode 6b described above can be reversed. That is, at the start of scanning, a negative potential may be applied to the plate-like electrode 6a and a positive potential may be applied to the plate-like electrode 6b. In this case, the eccentric direction (the direction of displacement along the X-axis direction) of the first slit member 11B and the second slit member 12B only needs to be opposite to the direction described in the second embodiment.

[0176] In addition, in the streak tube, one or both of the first slit member and the second slit member may be omitted. In addition, the first slit members 11 and 11B may be disposed at positions separated from the third electrode 9c. In addition, the second slit members 12 and 12B may be disposed in contact with the first electrode 9a, or may be disposed at positions separated from both the first electrode 9a and the aperture electrode 5 (disk-shaped electrode 5b) between the first electrode 9a and the aperture electrode 5. When the second slit members 12 and 12B are disposed in contact with the first electrode 9a, the second slit members 12 and 12B have the same potential as the first electrode 9a.

[0177] In addition, the displacement amounts of the first slit member 11B and the second slit member 12B can also be appropriately changed. For example, since the energy distribution and angular distribution of the photoelectrons released in the container 2 vary depending on the type of the photocathode 7 used for the streak tube, the displacement amount of the second slit member 12B can be appropriately adjusted within a range of, for example, 0.1 mm to 0.4 mm according to the type of the photocathode 7. By changing the displacement amount of the second slit member 12B according to the type of the photocathode 7 in this way, the electron group that deteriorates the time resolution can be appropriately shielded by the second slit member 12B. In addition, in the present embodiment, the setting signal generation unit 18 controls both the third electrode voltage source 16 and the scanning voltage generation unit 17, but the third electrode voltage source 16 and the scanning voltage generation unit 17 can also be controlled by separately prepared control devices. That is, the control unit that controls the third electrode voltage source 16 and the scanning voltage generation unit 17 can be constituted by a single control device or can be constituted by a plurality of control devices. In addition, the control unit that controls the third electrode voltage source 16 can also be configured to only control the on / off of the third electrode voltage source 16. In addition, in the present embodiment, a plurality of voltage sources are used for the power supply of each structure, but it is also possible to supply power by generating a plurality of voltages suitable for each structure by using a single voltage source.

[0178] In addition, in the present embodiment, the first electrode 9a and the second electrode 9b are set to the same potential by being electrically connected to each other, but the structure for setting the first electrode 9a and the second electrode 9b to the same potential is not limited to the above structure. For example, the first electrode 9a and the second electrode 9b can also be configured to be supplied with the same potential from mutually separate power supply paths (for example, different control units). In addition, the first electrode 9a and the second electrode 9b can also be individually grounded. The same applies to the structure for setting the first slit members 11 and 11B and the second electrode 9b to the same potential and the structure for setting the second slit members 12 and 12B and at least one of the aperture electrode 5 and the first electrode 9a to the same potential.

[0179] Description of Reference Numerals

[0180] 1A, 1B, 1C, 1D, 1E, 1F... streak tubes, 2... container, 2a... incident panel, 2b... output panel, 6, 6E... scanning electrodes, 6a, 6Ea... plate electrodes (first plate electrodes), 6b, 6Eb... plate electrodes (second plate electrodes), 7... photocathode, 8... fluorescent screen, 9... one-dimensional electron lens, 9a... first electrode, 9b... second electrode, 9c... third electrode, 10a, 10b, 10c, 10d... openings, 11, 11B... first slit members, 12, 12B... second slit members, 11a... slit (first slit), 12a... slit (second slit), 18... setting signal generation unit (control unit), CS... center plane, L... light to be measured.

Claims

1. A streak tube, wherein: Comprising: A container having an incident panel and an output panel; A photocathode disposed within the container that releases electrons in response to the measured light incident from the incident panel; A scanning electrode disposed within the container, composed of a pair of plate electrodes opposed to each other in the scanning direction along the output panel, and scans the electrons in the scanning direction; A plurality of electrodes disposed between the photocathode and the scanning electrode, forming an electron lens that focuses the electrons, and each provided with an opening through which the electrons pass; And A control unit that controls the potential applied to at least one of the plurality of electrodes, The plurality of electrodes include: a first electrode disposed at the position closest to the incident panel; A second electrode disposed at the position closest to the output panel; and a third electrode disposed between the first electrode and the second electrode separately from the first electrode and the second electrode, The control unit applies a potential higher than the potential of the first electrode and the potential of the second electrode to the third electrode.

2. The streak tube according to claim 1, wherein: The first electrode and the second electrode are at the same potential.

3. The streak tube according to claim 1, wherein: Further comprising: a first slit member disposed between the electron lens and the scanning electrode, and having a first slit having a width smaller than the width of each of the openings of the plurality of electrodes in the scanning direction, The control unit, by controlling the potential applied to the scanning electrode, at the start of scanning of the scanning electrode, applies a positive potential to a first plate electrode that is one of the pair of plate electrodes, and applies a negative potential to a second plate electrode that is the other of the pair of plate electrodes, The center of the first slit in the scanning direction is disposed at a position separated from the center plane passing through the center of the electron lens and orthogonal to the scanning direction, on the side where the first plate electrode is located.

4. The streak tube according to claim 3, wherein: The first slit member and the second electrode are at the same potential.

5. The streak tube according to any one of claims 1 to 4, wherein: Further comprising: a second slit member disposed between the electron lens and the incident panel, and having a second slit having a width smaller than the width of each of the openings of the plurality of electrodes in the scanning direction, The control unit, by controlling the potential applied to the scanning electrode, at the start of scanning of the scanning electrode, applies a positive potential to a first plate electrode that is one of the pair of plate electrodes, and applies a negative potential to a second plate electrode that is the other of the pair of plate electrodes, The center of the second slit in the scanning direction is disposed at a position separated from the center plane passing through the center of the electron lens and orthogonal to the scanning direction, on the side where the second plate electrode is located.

6. The streak tube according to claim 5, wherein: It further includes: an aperture electrode, which is disposed between the second slit member and the incident panel and is provided with an opening for allowing the electrons to pass through. The second slit member has the same potential as at least one of the aperture electrode and the first electrode.

7. The streak tube according to claim 1, wherein the incident panel has a light incident surface for the light to be measured to enter, and a photoelectric surface forming surface located on the side opposite to the light incident surface and formed with the photoelectric surface. The photoelectric surface forming surface is formed into a curved surface that is recessed toward the light incident surface side.

8. The streak tube according to claim 1, wherein at the start of the scan of the scan electrode, the control unit applies a positive potential to the first plate-shaped electrode, which is one of the pair of plate-shaped electrodes, and applies a negative potential to the second plate-shaped electrode, which is the other of the pair of plate-shaped electrodes, by controlling the potential applied to the scan electrode. The distance between the end closest to the incident panel of the inner side surface of the first plate-shaped electrode facing the center plane passing through the center of the electron lens and orthogonal to the scan direction and the center plane is shorter than the distance between the end closest to the incident panel of the inner side surface of the second plate-shaped electrode facing the center plane.

9. The streak tube according to claim 1, wherein the pair of plate-shaped electrodes are traveling-wave type electrodes configured such that the applied potential varies synchronously with the traveling speed of the electrons between the pair of plate-shaped electrodes.

10. A streak tube, wherein it includes: a container having an incident panel and an output panel; a photoelectric surface disposed inside the container that releases electrons according to the light to be measured incident from the incident panel; a scan electrode disposed inside the container, which is composed of a pair of plate-shaped electrodes facing each other in the scan direction along the output panel, and scans the electrons in the scan direction; a plurality of electrodes disposed between the photoelectric surface and the scan electrode, forming an electron lens for focusing the electrons, and each provided with an opening for the electrons to pass through; a control unit that controls the potential applied to the scan electrode and the potential applied to at least one of the plurality of electrodes; a first slit member disposed between the electron lens and the scan electrode and having a first slit with a width smaller than the width of each of the openings of the plurality of electrodes in the scan direction; and a second slit member disposed between the electron lens and the incident panel and having a second slit with a width smaller than the width of each of the openings of the plurality of electrodes in the scan direction. At the start of the scan of the scan electrode, the control unit applies a positive potential to the first plate-shaped electrode, which is one of the pair of plate-shaped electrodes, and a negative potential to the second plate-shaped electrode, which is the other of the pair of plate-shaped electrodes. The center of the first slit in the scan direction is disposed at a position separated from the center plane on the side where the first plate-shaped electrode is located with respect to the center plane passing through the center of the electron lens and orthogonal to the scan direction. The center of the second slit in the scanning direction is disposed at a position separated from the center plane on the side where the second plate-shaped electrode is located, with respect to the center plane.

Images