JPS5858006B2 - streak tube - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a streak tube for detecting ultrafast optical phenomena in the picosecond range.

A conventional I-IJ tube has a cylindrical high-vacuum container with a translucent photocathode formed on one end surface, and a photoelectron accelerating electrode, a focusing electrode, a deflection plate, a fluorescent plate, etc. on the front surface of the translucent photocathode. It is something that

That is, a laser beam or the like whose intensity changes in the picosecond region is incident on the photocathode through a slit, and at the same time a sweep voltage is applied to the deflection plate to determine the relationship between the time and intensity of the incident light and the position on the fluorescent plate. Convert to relationship with luminescence intensity,
This can be photographed or converted into a video signal using a television camera and analyzed.

However, in order to detect high-speed changes in light using such a streak tube, it is necessary to increase the amount of emitted photoelectrons per unit time by injecting strong light to increase the amount of incident light per unit time. .

In addition, the translucent photocathode has a fairly high sheet resistance, so when a large amount of photoelectrons are emitted instantaneously, the potential at the light incident area fluctuates, making it difficult to focus well and reducing temporal resolution. There was a drawback.

For example, when a photocathode is formed of potassium bromide or the like for detecting vacuum ultraviolet rays, the resistance is extremely high and a potential difference is generated also in the thickness direction, further increasing the above-mentioned drawbacks.

The present invention provides a streak tube that does not have these drawbacks.

FIG. 1 is a longitudinal cross-sectional view of an embodiment of the present invention, FIG. 2 is a diagram showing the light incident plane in FIG. 1, and FIG.
It is an enlarged view of a part of the A cross section.

A terminal conductor 2 made of an annular metal plate is sealed to one end of the cylindrical glass airtight container 1 which has been evacuated to a high vacuum in this way, and the conductor layer 3 deposited on the end surface of the container is applied as described above. It is connected to the terminal conductor 2.

The conductor layer 3 is deposited sufficiently thickly and is opaque, but a plurality of parallel non-deposited portions 4, 4, .

An arbitrary semi-transparent photocathode 5 is formed on this conductive layer 3, and a fluorescent plate is formed by applying a fluorescent material 6 to the other end surface of the container 1 and depositing a conductive layer 7 thereon. It is.

Furthermore, inside the container 1, a mesh-like accelerating electrode 8 is arranged parallel to the photocathode 5 at a distance of several millimeters in front of the photocathode 5, and a cylindrical accelerating electrode 8 is arranged between the accelerating electrode and the fluorescent plate. A focusing electrode 9 and an anode 10 are provided, and inside the anode 10 is a pair of deflection plates 1 for deflecting photoelectrons emitted from the photocathode 5 in a direction perpendicular to the striped arrangement in the conductor layer 3.
1.12 is provided, one of which 11 is connected to the anode 10.

A channel plate 13 is attached to the end of the anode 10 so as to face the fluorescent plate, and the electrode on the incident surface side is connected to the anode.

This channel plate 13 is a glass plate with a large number of fine through-holes, the inner surface of which serves as a secondary electron emitting surface, and electrodes formed on both sides of the glass plate, with hundreds to thousands of holes between the electrodes. When a Porto voltage is applied and an electron image is projected onto the electrode surface on the low-potential side, the electrons incident on each part are repeatedly reflected on the inner surface of the minute through-hole, and several electrons are projected from the electrode surface on the high-potential side. A thousand times more electrons are emitted.

In the streak tube described above, for example, the anode electron 14 is grounded and the photocathode terminal 15, accelerating electrode terminal 16, and focusing electrode terminal 17 are applied with -6.5 KV, respectively.

Voltages of -5 KV and -5.6 KV are applied, and voltages of 0.9 KV and 3.9 KV are applied to the fluorescent plate side electrode terminal 18 and the fluorescent plate terminal 19 of the channel plate, respectively.

In this state, as shown by the chain line p in FIG. 2, a laser beam or the like whose intensity changes in the picosecond region is made incident on the photocathode 5.

That is, the light beam p has a band shape in the direction in which the stripes of the conductor layer 3 are arranged, and its width is several tens of microns.

When a sweep voltage is applied to the deflection plate terminal 20 simultaneously with the incidence of this light beam, the electron beam e emitted from the photocathode 5 is accelerated by the mesh electrode 8 and is accelerated by the electron lens between the focusing electrode 9 and the anode 10. It is focused and enters between the deflection plates 11 and 12, and is deflected at an angle corresponding to the time of incidence to form an image on the channel plate 13.

Therefore, electrons multiplied several thousand times are emitted from the electrode surface on the high potential side of the channel plate 13, accelerated by the electric field between the electrode and the fluorescent plate, and incident on the fluorescent plate.

In other words, since the phosphor 6 is excited by the incident electrons and emits light, an image appears on the phosphor plate in which the relationship between time and light intensity in the incident light is converted into a relationship between position and intensity of the fluorescent light. This image can then be photographed or converted into a video signal using a television camera for analysis.

In the above embodiment, a striped conductor layer 3 is provided on the photocathode substrate and a photoelectric sieve 5 is formed thereon. If the value is extremely high, it is also possible to first form a translucent photocathode 5 on the substrate and then provide a striped conductor layer 3 thereon as shown in FIG.

In this way, the present invention has a structure in which a translucent photocathode 5 and a striped conductor layer 3 are superposed and formed on a transparent substrate at one end of an airtight container, and the conductor layer is connected to a terminal conductor 2. It is.

Therefore, the photocathode 5 is formed substantially in the form of stripes, each part of which is connected to the conductor layer 3 at a close distance.

Therefore, even when an extremely large amount of photoelectrons are emitted instantaneously, the voltage drop due to the resistance in the plane direction of the photocathode can be made small enough to be ignored.

In other words, since it is possible to prevent the potential of the emitting part from changing due to the emission of photoelectrons, the photocathode and the accelerating electrode 8
It does not have the drawbacks that the electric field between the two is disturbed, the focusing conditions change, the image on the fluorescent plate is enlarged, and the temporal resolution is degraded.

Furthermore, when the conductor layer 3 is formed on the photocathode 5 as shown in FIG. 4, voltage drop in the thickness direction of the photocathode is also prevented.
The above effect can be obtained even when the resistance value of the photocathode is extremely high.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of an embodiment of the present invention, FIG. 2 is a front view of the photocathode in FIG. This figure is a sectional view of the same part as FIG. 3 in another embodiment of the present invention. In the figure, 1 is an airtight container, 2 is a terminal conductor, 3 is a conductor layer, 4 is a removed portion of the conductor layer 3, 5 is a photocathode, and 6 is a
is a fluorescent material, 7 is a conductive layer, 8 is an accelerating electrode, 9 is a focusing electrode,
10 is an anode, 1112 is a deflection plate, and 13 is a channel plate.

Claims (1)

[Claims] 1. Forming a translucent photocathode on a transparent substrate at one end of a cylindrical container evacuated to high vacuum, and superimposing a striped conductor layer on the photocathode to turn the conductor layer into a terminal conductor. connected to the front surface of the photocathode, an accelerating electrode and a focusing electrode for photoelectrons emitted from the photocathode, a pair of deflection plates that deflect the photoelectrons in a direction perpendicular to the arrangement of stripes in the striped conductor layer, and excitation by the photoelectrons. A streak tube characterized in that it is provided with a fluorescent plate that emits light.