JPS5996640A - Streak tube and its production method - Google Patents

Abstract

PURPOSE:To obtain a streak tube not generating unnecessary emission by providing a bulkhead with an opening including the tube axis between a photoelectric surface and a deflection electrode, maintaining the cover of the opening at a closed position while the photoelectric surface is produced, and normally opening it to form a pass route of electrons. CONSTITUTION:A space in a vacuum airtight container 3 containing a photoelectric surface 4, a mesh electrode 5, a focus electrode 6, and an aperture electrode 7 and a space in the container 3 containing a deflection electrode 8 and a phosphor screen 9 are divided by a bulkhead 30. An opening 13 is provided on the bulkhead 30 and a cover 14 is provided facing the opening 13. The center of the opening 13 is made to match a tube axis and its position in the tube axis direction is located at or near a crossover point 11 where a photoelectron beam is focused. During a production process, the cover 14 closes the opening 13 by gravity, and antimony stored in a branch tube 18 is extracted and deposited on a photoelectric surface substrate 1. Next, an alkali metal in a branch tube 17 is evaporated and combined, and after the stabilizing treatment the process is completed. Then, the attitude of the container 3 is changed, the opening 13 is opened and the cover 14 is fixed, thus unnecessary emission can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a streak tube that can be used negatively for analyzing the temporal light intensity distribution of a light source, and a method for manufacturing the same.

The sleak tube displays changes in the incident light on the order of nanometers over a length of several tens of millimeters on the fluorescent surface, and its time resolution is so excellent that it can read changes of less than 2 picoseconds. . For this reason, streak tubes are used for waveform analysis of laser pulse light.

First, the structure of the conventional streak tube and the problem to be solved by the present invention will be briefly explained with reference to FIG.

FIG. 1 is a longitudinal sectional view showing the configuration of a conventional streak tube, and a schematic diagram showing the relationship between a photocathode and an optical image.

One end surface of the vacuum-tight container 3 of the nodry leak tube forms a window t51 through which the optical image to be processed enters, and the other end surface forms a window 2 through which the processed optical image is output.

Along the tube axis of this vacuum-tight container 3, there is an entrance window l and an exit window 2.
and the photocathode 4. No-Nosoyu electrode 5゜Focusing electrode 6
．．゛Aperture electrode 7. Deflection electrode 8. A phosphorescent surface 9 is disposed.A higher voltage is applied to the photocathode 4 to the mesh electrode 5, the focusing electrode 6, and the aperture electrode 7 in this order. A linear optical image 4 passing through the center of the photocathode 4 is applied to the photocathode 4 through the entrance window 1 using a device (not shown).
Suppose that a is projected. The photocathode 4 emits an electron image corresponding to the optical image, and the emitted electrons are accelerated by the mechanical electrode 5, focused by the focusing electrode 6, passed through the aperture electrode 7, and then reflected by the deflection electrode 8. Fluorescent surface 9 through the gap
Drive in the direction of. During the period during which the linear electron image passes through the gap between the deflection electrodes 8, a deflection voltage is applied to the deflection electrode 8 described in I) 11 above. The direction of the electric field generated by this voltage is perpendicular to the tube axis and the linear electron image (perpendicular to the plane of the paper in the cross-sectional view of FIG. 1), and its strength is proportional to the deflection voltage. A linear electron beam is scanned perpendicularly to the linear direction of the fluorescent surface 97, so that a fiber-like optical image projected onto the photocathode 4 is finally formed on the fluorescent surface 9. An optical image, a so-called streak image, is formed by temporally sequentially distributing the light perpendicular to the linear direction. Therefore, the change in brightness of the streak image in the array direction as well as in the sweep direction represents the temporal change in the intensity of the optical image applied to the photocathode 4.

Such a streak tube is generally manufactured by the following method.

First, ■ a glass cylinder that constitutes a side wall of the airtight container 3; a first glass disk that constitutes one bottom surface of the vacuum-tight container 3, receives an optical image, and serves as a substrate for a photocathode; and ■ an airtight container. A second glass disk constitutes the other bottom surface of 5.3 and serves as a window for outputting an optical image and a substrate for a fluorescent surface, and a mesh electrode 5.3. Focusing electrode 6° Aperture electrode 7. An electrode section (o) constituting the deflection electrode 8 is prepared.

Next, the electrode fjls JrA is assembled and attached inside the glass cylinder. At this time, an andymony evaporation source is installed at an appropriate position facing the photocathode substrate, for example, by storing small pieces of antimony in a tungsten coil.

At the same time, a phosphor is applied to one side of the second glass disk. Next, the first glass disk and the second glass disk are hermetically sealed to appropriate sides of the bottom surface of the glass cylinder.

Next, a branch pipe is provided on the III wall of the airtight container, and the alkali metal source is contained in this branch pipe, which is then evacuated through this exhaust pipe provided on the side wall of the airtight container.

Next, the tungsten coil is energized to deposit antimony on the photocathode substrate, and then the alkali metal is gradually introduced into the container from the branch pipe, and at the same time the sensitivity of the photocathode is monitored;
Stops when the maximum sensitivity is reached or slightly exceeded. Cut off this posterior branch.

After that, cut out the JJI trachea to complete the leak tube.

As can be understood from the above description of the manufacturing method, when an alkali metal is pumped into an airtight container, each electrode
It is unavoidable that alkali metals will be deposited, albeit minutely.

When the streak tube manufactured by the above process is operated, the alkali metal causes the inconvenience that the fluorescent surface emits light even in the absence of a large amount of light.

It shines particularly brightly when a high frequency voltage is applied to the deflection electrode and the deflection electrode is repeatedly operated.

Such light emission becomes a background of the streak image, lowering the S/N ratio and narrowing the range.

The inventor of the present application believes that the above-mentioned light emission is caused by photoelectrons generated when light generated by excitation or ionization of gas molecules or atoms that collide with electrons is incident on a photocathode, or that electrons or ions are airtight. 1
After researching the problem, I discovered that the main cause was near the deflection electrode.

Even if a high voltage is applied between the Zunawaji photocathode 4 and the aperture electrode 7, the light emission from the fluorescent surface 9 will be extremely weak unless a voltage is applied between the opposing deflection electrodes. I learned that when I add , the luminescence of the fluorescent surface becomes significantly stronger.

A first object of the present invention is to provide a streak tube that does not cause the above-mentioned undesired light emission.

In order to achieve the above main object, the streak tube according to the present invention deflects and observes photoelectrons emitted from a photocathode. a partition having an opening disposed therein and including a tube axis; a lid movable between a position in which the opening is closed and a position in which the opening is opened; and means for moving the lid to the open position; The lid is kept in a closed position and normally left open to form a path for electrons to pass through.

Still another object of the present invention is to provide a method for manufacturing the streak tube.

In order to achieve the above-mentioned other objects, the method for manufacturing a streak tube according to the present invention is a method for manufacturing a streak tube in which photoelectrons emitted from a photocathode are deflected and observed. A first space containing at least a surface on which a photocathode is formed and a focusing electrode, and a second space containing at least a deflection electrode and a fluorescent surface are opened along the tube axis.
an assembly process in which a partition wall having a partition wall is separated at a position where the photoelectron crossover point is located at or near the photoelectron crossover point, and a lid is placed in the opening, which is closed in step 2; a step of evacuating the first and second spaces, a step of introducing a metal forming a photocathode from a branch pipe communicating with the first space to form a photocathode, and cutting the branch pipe. The process consists of a step of evacuation while heating the inside, and ejecting the photocathode forming hole '1 which did not contribute to the formation of the photocathode, and a step of removing the lid from the opening after evacuation is completed. ing.

That is, in the manufacturing process, the first space is filled with alkali metal vapor for forming the photocathode, but care is taken to prevent the alkali metal vapor from reaching the deflection electrode in the second space, and during operation, the aperture is kept to a minimum. Since the first space having the photocathode and the second space having the deflection electrode are connected, movement of the alkali metal is less likely to occur during operation. Therefore, even during use, the deflection electrodes are not contaminated by residual alkali metals. Further, even if light is emitted due to ionization in the vicinity of the deflection electrode or electrons collide with the inner wall of the airtight container, the light does not reach the photocathode, thereby preventing unnecessary light emission from the fluorescent surface.

Hereinafter, the present invention will be further described with reference to the drawings and the like.
explain.

FIG. 2 is a cross-sectional view showing the manufacturing process of the SL-IJ pipe of the present invention. Parts common to the streak tube shown in FIG. 1 are designated by the same symbols.

First, the configuration of this streak tube will be explained.

The streak tube according to the invention has a photocathode 4, a photocathode 1
! Ii! 5. The space inside the vacuum-tight container 3 containing the focusing electrode 6 and the aperture electrode 7, and the space containing the deflection electrode 8 and the fluorescent surface 9]1. The space inside the vacuum-tight container 3 is divided by partition walls 30. An opening 13 is provided in the partition wall 3o, and a lid 14 is made to correspond to the opening 13. Figure 3 (A
), the lid 14 closes the opening 13, FIG. 3(B)
This figure shows a state in which the lid 4 opens the opening 13.

The lid 14 is rotatably supported on the partition wall 30 by a pin 15, and during the manufacturing process it is shown in FIGS. 2 and 3 (A).
It is maintained in the closed shape shown in FIG. 3, and after completion, it is clamped and fixed by leaf springs 16 provided on the partition wall 30. The center of this aperture 13 is aligned with the tube axis, and its position in the tube axis direction is located near the crossover point 11 or 'c (7) J9 where the photoelectron beam is focused.

Next, a method of manufacturing the aforementioned leak pipe will be explained with reference to FIG. 2 as well.

An exhaust pipe 19 communicating with a vacuum pump (not shown) is provided in a space (hereinafter referred to as a first space) in which the photocathode 4, mesh electrode 5, focusing electrode 6, and aperture electrode 7 are to be included.

In addition, the space inside the vacuum-tight container 3 (hereinafter referred to as the second space) containing the deflection electrode 8 and the fluorescent surface 9 is also filled with an exhaust pipe 2o.
Set ζ.

These spaces are separated each time the lid 14 closes the opening 13 of the partition wall during the manufacturing process.

A branch pipe 17 containing an alkali metal and a branch pipe 18 containing an antimony evaporation source are connected to the first space.

First, each space in the container is evacuated to a predetermined vacuum.

Next, a magnetic force is applied from the outside through the branch pipe 18 that houses the antimony evaporation source, and the antimony is taken out to the inside of the streak tube, heated by electricity, and antimony is evaporated onto the photocathode substrate 1 .

Next, the alkali metal is evaporated from the branch pipe 17 and combined with the antimony on the photocathode substrate 1.

At the same time, the photoelectric sensitivity of the photocathode is monitored, and when the maximum sensitivity is somewhat exceeded, the branch pipe 18 containing the alkali metal is cut off.

Also, cut out the branch pipe 17 containing the algae source.

The container is further heated to stabilize the photocathode.

At this time, excess alkali metal is discharged to the outside of the container 3.

After this, the exhaust pipes 19 and 20 are cut out, and the l-leak bamboo number 51 is completed.

After completion, when the streak tube is turned upside down as shown in Fig. 2 (into its normal usage position), the lid 14 will be placed under the opening 13 due to the gravity acting on itself, and the tip of the lid 14 will be held by the leaf spring 16. Captured and fixed. Note that FIG. 3(B) shows the state of use and the top and bottom are reversed.

FIG. 4 is an explanatory view showing a second configuration of the partition wall and the lid of the S+-IJ- pipe.

The M14 is fixed to a support rod 41 provided on the outer periphery of the partition wall 30 via a bimetal 42 .

When the streak tube is at room temperature, M14 is used as shown in Figure 4 (C).
The opening 13 is not covered as shown in FIG.

When sending alkali metal, the inside of the streak tube is about 20
Since it is heated to 0° C., the bimetal 42 is curved as shown in FIG. 4(B) and kept in a state covering the opening 13.

Such a configuration can also prevent the alkali metal from entering the second space.

FIG. 5 is an explanatory diagram showing a third configuration of the partition wall of the streak tube and the mesh.

The lid 13 is fixed to one end of a rotating shaft 51 rotatably directed to a shaft 5o provided on the partition wall 3o.

A head 52 made of a ferromagnetic material (3) is fixed to the other end of the rotating shaft 51, and is kept in the position shown in FIGS. 5(A) and 5(B) during the manufacturing process to close the opening 13.

After the manufacturing is completed, by applying a magnetic force to the head from the outside or changing the posture of the streak tube, the leaf spring 53 is placed in a position that does not prevent the opening of the opening 13, as shown in FIG. 5(C).
is maintained by

FIG. 6 is an explanatory diagram showing a fourth configuration of the partition wall and lid of the streak tube.

Figure 6 (A) (B) is the manufacturing state, Figure 6 (C) (D
) indicates the usage status.

1. In the J-shaped state, the lid I4 is pressed against the opening 13 of the partition wall 30 by the spring 61.

Reference numeral 60 denotes a frame that receives the lid 14, and after the manufacturing is completed, the lid 1
Accept 4. Note that the spring 61 has a bent end 61a, which comes into contact with the shoulder portion of the lid 14 and serves to prevent the lid 14 from moving.

The streak tube according to the invention is constructed as described above, and f
Since it is a J-shaped structure, alkali metal is not introduced into the vicinity of the deflection electrode when forming the photocathode.

Further, during use, the partition wall 30 makes it difficult for light emitted near the deflection electrode to reach the photocathode, thus solving the above-mentioned problem of unnecessary light emission.

Next, the results of a comparative test of images on a fluorescent surface of streak tubes manufactured by the manufacturing method of the present invention and streak tubes manufactured by the conventional manufacturing method whose shapes are similar will be described.

Pulsed light source (mode-lock dye laser light with repetition rate of 1
30 MIIz) onto the photocathode of the streak tube, and a sine wave voltage synchronized with the pulsed light is applied to the deflection electrode to perform continuous and repeated deflection.

FIG. 7 (8) shows a comparison between the output of the streak tube according to the present invention and the output of a conventional streak tube.

In the case of the conventional product shown in FIG. 7 (Δ), the luminance of the troughs, which is background noise, reaches 90% of the peak luminance.

On the other hand, it can be said that the ground IX noise in the output of the streak tube according to the present invention shown in FIG. 7(B) is removed to an almost negligible level, which is less than 1% of the peak.

[Brief explanation of drawings]

FIG. 1 is a vertical cross-sectional view showing the structure of a conventional S-IJ-ritake, and a schematic diagram showing the relationship between a photocathode and an optical image. FIG. 2 is a sectional view showing the state of the manufacturing process of the streak tube of the present invention. FIG. 3 is an explanatory diagram showing the relationship between the partition wall and the lid of the streak tube shown in FIG. 2. FIG. 4 is an explanatory diagram showing a second configuration of the partition wall and lid of the leak tube. FIG. 5 is an explanatory view showing a third configuration of the partition wall and lid of the leak tube. FIG. 6 is an explanatory view showing a fourth configuration of the partition wall and lid of the leak tube. FIG. 7 is a graph comparing the operating characteristics of a leak tube according to the present invention and a conventional equivalent. ]...Window 2 through which the optical image enters...Output window 3...Vacuum-tight container 4...Photocathode 5...Methoche electrode 6...Focusing electrode 7...Average electrode 8... Deflection electrode 9... Fluorescent surface 11... Crossover point 13... Opening 14 provided in the partition wall... Lid 16... Spring 17... Branch pipe 18 for accommodating alkali metal. ... Branch pipe I9 that accommodates the antimony evaporation source ... Photocathode side (first
exhaust pipe 20 on the fluorescent surface side (second space)... partition wall 42... bimetal 52... ferromagnetic piece 60... frame 61... spring Patent Applicant Hamamatsu Television Co., Ltd. Agent Patent Attorney Hisashi Inoro 6 Figure-199-

Claims (1)

[Claims] (1) In a streak tube that deflects and observes photoelectrons emitted from a photocathode, the streak tube is arranged at or near the photoelectron crossover point between the photocathode and the deflection electrode, and includes the tube axis. A partition wall having an opening, a lid movable between a position where the opening is closed and a position where the opening is opened, and means for moving the lid to the open position, the lid being maintained in the closed position during photocathode manufacturing. (1) A streak tube characterized in that it is configured to be opened to form a passage path for electrons. (2) the lid is rotatably supported on the partition wall;
The streak according to claim 1, which is in a position where the opening is closed due to gravity during the photocathode manufacturing process, is moved by changing the attitude of the container after the manufacturing process, and is fixed by a spring provided on the partition wall. tube. (:3) The lid is supported by the partition wall via a bimetal, and the bimetal is designed to bring the lid to the opening at the temperature when forming the photocathode, and to withdraw it from the opening at the temperature of the photocathode. A streak tube according to claim 1. (4) The lid is slidably provided on the partition wall, and is pressed against the opening by a spring provided on the partition wall, and when the container is retracted from the opening by changing the attitude of the container after completion of the operation, the lid is moved by the spring. The streak tube according to claim 1, which is held in a retracted position. (5) A method for manufacturing a streak tube that deflects and observes photoelectrons emitted from a photocathode, which includes at least a surface on which a photocathode is formed and a focusing electrode formed in a container that is evacuated to form a vacuum. A first space and a second space including at least a deflection electrode and a fluorescent surface are separated by a partition having an opening in the tube axis at a position where the opening is located at or near a photoelectron crossover point, and the opening The manufacturing process includes an assembly process in which a closed lid is provided in the part, a process in which the first and second spaces are evacuated, and metal forming the photocathode is removed from a branch pipe communicating with the first space. A step of introducing the photocathode to form a photocathode, cutting the branch pipe ζ, and heating the inside gj
J) It is characterized by comprising a step of discharging the material for forming the photocathode which did not contribute to the formation of the photocathode during the IJI process, and a step of removing the lid from the opening after the completion of the IJI process. A method for manufacturing a streak tube.