JPH01302643A - X-ray image multiplier - Google Patents

Abstract

PURPOSE:To reduce welding positions and reduce work processes by providing a reinforcing member inside the tube of an input window to prevent the deformation of the input window. CONSTITUTION:An input window 3 is hermetically connected to the opening end of a bottomed cylindrical vacuum envelope 1, a reinforcing member 8 is provided inside this connection portion. This reinforcing member 8 is provided to prevent the deformation of the input window 3, it is circularly provided along inner faces of both the vacuum envelope 1 and the input window 3, its cross section is formed in a nearly triangular shape. In this case, the reinforcing member 8 is not hermetically connected to the input window 3. since a vacuum airtight connection section is provided at one position, the productivity such as the confirmation of the vacuum airtightness by the surface oxidation processing, welding process, and blowholes of the welding section is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to an X-ray image intensifier, and particularly to a reinforcing structure for an input window thereof.

(Prior Art) In general, in an X-ray image intensifier, quantum noise in X-ray images is one of the causes of image quality deterioration. Therefore, the material and thickness of the input window of the XL image intensifier are determined by the X-ray transmittance (especially soft X-rays)
Therefore, it is necessary to make it as thin as possible using a material with high X-ray transmittance.

However, making the input window thinner reduces the strength of the input window,
The thickness of the input window is determined by the strength of the input window since it may be deformed during the manufacturing process.

Therefore, the strength is improved by providing a reinforcing member around the input window. As an example of this,
There is one described in Japanese Patent No. 1-230622, which is constructed as shown in FIG.

That is, a spherical input window 3 is hermetically sealed to the opening of the bottomed cylindrical vacuum envelope 1 via the intermediate member 2 . In this case, at least two joint parts are required: the vacuum envelope 1 and the intermediate member 2, and the intermediate member 2 and the input window 3.

Inside the vacuum envelope 1, a photocathode 4 is provided on the input side facing the input window 3, and an output fluorescent screen 5 is provided on the output side. Furthermore, a grid electrode 6 is arranged along the side surface of the vacuum envelope 1 and is fixed to the vacuum envelope 1 by a support member 7.

(Problem to be Solved by the Invention) Usually, the vacuum envelope 1 and the input window 3 are made of aluminum, and methods for hermetically joining aluminum include TIG welding, brazing, pressure welding, etc. - Requires extremely difficult technology compared to methods of airtightly bonding other metals, such as iron alloys, to the membrane surface.

In particular, in welding, a strong oxide film exists on the surface of aluminum, and pretreatment is required before welding. Furthermore, crystal water in the oxide film causes blowholes in the weld. Furthermore. 1. Hydrogen solubility in the liquid phase is significantly higher than that in the same phase. <Due to its large size, blowholes are likely to occur in the welded area.

In this way, airtight joining of aluminum is extremely difficult. <
, since productivity is not very good, the number of joints should be minimized as much as possible.

This invention significantly improves productivity by providing a reinforcing member for the input window, making airtight contact only at one location.1. The object of the present invention is to provide an X-ray image intensifier tube.

[Structure of the Invention] (Means for Solving the Three Problems) In this invention, an input window is directly hermetically joined to the open end of a bottomed cylindrical vacuum envelope by welding, and furthermore, a vacuum outside is provided inside this joint portion. This is an X-ray image intensifier tube that is provided with reinforcing members along both the envelope and the input window.

(Function) According to the present invention, since the reinforcing member is not hermetically sealed to the input window, the material can be selected regardless of the input window or the vacuum envelope. For example, it is also possible to use stainless steel in order to increase the space inside the pipe. Furthermore, in order to prevent scattered X-rays from entering from oblique directions, it is also possible to use a material with low X-ray transmittance.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

The X-ray image intensifier tube of this invention is constructed as shown in FIG. An input window 3 is hermetically sealed to the open end of the input window 1 by TIG welding. Further, a reinforcing member 8 is provided inside this joint portion.

This reinforcing member 8 is intended to prevent deformation of the input window 3, and is formed in an annular shape 17 along the inner surfaces of both the vacuum envelope 1 and the input window 3, and has a substantially rectangular cross section. In this case, the reinforcing member 8 is not hermetically sealed to the input window 3.

Note that since the configuration other than the above is the same as that of the conventional example (FIG. 6), detailed explanation will be omitted. The photocathode and grid electrode in the vacuum envelope 1 are not shown in the drawing for convenience.

In this way, this invention has only one vacuum-tight joint, which greatly improves productivity, including surface oxidation treatment of welded parts, welding processes, and confirmation of vacuum-tightness due to blowholes, etc. I can do it. It also improves product reliability.

(Other Embodiments) FIGS. 2 to 5 show other embodiments of the present invention, which provide the same effects as the above embodiments.

In the embodiment shown in FIG. 2, the reinforcing member 8 is integrated with the vacuum envelope, and even with this structure, there can be only one airtight joint.

In this case, since no additional reinforcing member is required, productivity can be improved.

The embodiment shown in FIG. 3 has a structure in which the reinforcing member 9 also serves as a support portion for supporting one or more structures such as the photocathode 74 and the grid electrode IM6. In this structure,
There is no need to separately provide a supporting member, and the process of welding the supporting member and the vacuum envelope 1 can be omitted, improving productivity.

Furthermore, if a metal with strong bending strength, such as stainless steel, is used in the shape of the reinforcing portion +49, it is also possible to arrange a getter material or the like on the reinforcing member 9.

In the embodiment shown in FIG. 4, a getter material 11 is provided on the reinforcing member 10. In this case, there is no need to provide a getter material fixing ring, improving productivity. .

In the embodiment shown in FIG. 5, the vacuum envelope] and the TIG of the input window 3 are
Since the welding direction is parallel to the tube axis direction, the maximum outer diameter of the vacuum array enclosure 1 can be made thinner, and the shape of the tube container 13 can be made smaller.

12 is a reinforcing member.

In each of the above embodiments, if a metal material with low X-ray transmittance is used for the reinforcing member, it is possible to block scattered X-rays that obliquely enter the input fluorescent screen of the photocathode 4.

[Effects of the Invention] As explained above, according to the present invention, a reinforcing member is provided on the inside of the input window to prevent deformation of the input window.
There are fewer welding points compared to conventional methods. Therefore, work steps such as oxidation film treatment of welded parts, welding processes, and airtightness tests can be reduced, resulting in a significant improvement in productivity and product reliability.

[Brief explanation of the drawing]

FIG. 1 is a partially cut-away front view showing essential parts of an X-ray image intensifier according to one embodiment of the present invention, and FIGS. 2 to 5 are partially cut-away views of other embodiments of the present invention. FIG. 6 is a partially cut-away front view of a conventional X-ray image intensifier. 1... Vacuum envelope, 3... Input window, 8.9.10.
12... Reinforcement member. Applicant's Representative Patent Attorney Takehiko Suzue Figure 1 Figure 2 Figure 3 Figure 4 Figure 5

Claims (1)

[Claims] The input window is directly hermetically joined to the open end of the bottomed cylindrical vacuum envelope by welding, and a reinforcing member is provided inside this joint part along both the vacuum envelope and the input window. X-ray image intensifier.