JPH07302561A - X-ray fluorescent multiplying tube device - Google Patents

Abstract

PURPOSE:To prevent the deterioration of image contrast by installing a specific mask on the outside air side of an output window. CONSTITUTION:An output fluorescent screen 5 is formed on an inside surface of an output window 3 joined to a vacuum envelope 1, and a mask 9 to prevent re-incidence on the window 3 by reflected light from an optical lens 7 is installed on the outside air side of the window 3. In order to prevent re-incidence on the window 3 by the reflected light, an inside diameter of the mask 9 is effective when it is narrower, but it is necessary to be within a range of not hindering the light condensation of an output visible radiation image on the lens 7. At least the surface of the mask 9 is desirable to be the one of not re-scattering the reflected light from the lens 7, and a hardly lustrous black substance is suitable for the surface. For example, a black plastic material having an unpolished fine recess-projection or a metallic material, whose surface is painted or laked in black, or the like is optimal. By constituting in this way, among the reflected light from the lens 7 in the output window 3, light re-incident on the window 3 can be restrained to the possible minimum level, and the detrioration of image contrast can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an X-ray fluorescence intensifier tube apparatus, and more particularly to the structure of the output section of the X-ray fluorescence intensifier tube.

[0002]

2. Description of the Related Art Generally, as shown in FIG. 3, an X-ray fluorescence multiplier has a cylindrical vacuum envelope 1 made of metal or glass.
The input window 2 is joined to one end and the output window 3 is joined to the other end. Inside the vacuum envelope 1, the input surface 4 is on the input side, the output fluorescent surface 5 is on the output side, and further on the side surface. A focusing electrode 6 is provided along the focusing electrode 6. In the X-ray fluorescence multiplier device, an optical lens 7 for collecting the output image of the output fluorescent screen 5 of the X-ray fluorescence multiplier and transmitting it to the image reproducing device is provided near the outside air side of the output window 3. Has been.

During operation of the X-ray fluorescence multiplier tube, X-rays (not shown) that have passed through the subject are converted into an electronic image on the input surface 4, accelerated and converged by the focusing electrode 6, and then output fluorescent screen 5.
To form a bright visible light image.

Further, the output part of the conventional X-ray fluorescence multiplier is
It is configured as shown in FIG. That is, an output phosphor screen 5 is formed inside the glass or plastic output window 3 bonded to the vacuum envelope 1 facing the vacuum. The output visible light image formed by the emission of the output fluorescent screen 5 is transmitted through the output window 3, condensed by the optical lens 7, and transmitted to the image reproducing apparatus.

[0005]

By the way, the light emitted from the output phosphor screen 5 is generated on the surface of the output window 3 on the vacuum side and the outside air side.
And reflection due to the different refractive index of the surface of the condenser lens 7 to reach different parts of the output fluorescent screen (straightening).
(Referred to as light), which results in reduced image contrast in the x-ray fluorescence intensifier.

As a means for improving them, conventionally, a non-reflective coating 8 for preventing vertical reflection on the outside air side surface of the output window is applied, and light scattering in the output window is prevented. In order to achieve this, a method of optically adhering a film or plate having a changed light transmittance to the output window (Japanese Patent Application Laid-Open No. HEI-1
-76645), the effect of improving the contrast characteristic is obtained.

For the purpose of preventing reflected light from entering the output window at the interface of the condenser lens, it has been considered to cover the outer peripheral portion of the output window with a black material (Japanese Patent Laid-Open No. 4-42). 1
62335). However, this method alone cannot sufficiently prevent the reflected light at the interface of the condenser lens that reenters the output window. The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an X-ray fluorescence multiplier tube device capable of preventing a decrease in image contrast.

[0008]

According to the present invention, an X-ray fluorescent device is provided with a mask for preventing re-incidence of reflected light from an optical lens to the output window on the outside air side of the output window of the X-ray fluorescent multiplier. It is a multiplier device.

[0009]

According to the present invention, re-incident light reflected from the optical lens in the output window of the X-ray fluorescence multiplier can be significantly suppressed from entering the output window. Therefore, it is possible to prevent a decrease in the contrast of the output image.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings. The present invention is an improvement in the vicinity of the output window of the X-ray fluorescent multiplier, and only the vicinity of the output surface will be described. The same parts as those in the conventional example are designated by the same reference numerals.

The X-ray fluorescence intensifier tube output section of the X-ray fluorescence intensifier tube apparatus according to the present invention is constructed as shown in FIG. That is, the output phosphor screen 5 is formed on the inner surface of the glass or plastic output window 3 bonded to the vacuum envelope 1.
Are formed. The electron e of the electron image is formed on the output phosphor screen 5.
A mask 9 is attached to the outside air side of the output window 3 which transmits the output visible light image formed by the contact with the light, to prevent the reflected light from the optical lens 7 from re-entering the output window.
In order to prevent the reflected light from the optical lens 7 from entering the output window 3, it is effective that the inner diameter of the mask 9 is narrower. In that case, the output visible light image is collected on the optical lens 7. It must be within the range that does not block light.

As shown in FIG. 2, the incident effective diameter of the optical lens is L, the distance between the incident effective diameter L and the optical image forming surface 10 is f, the thickness of the output window is T, and the refractive index of the output window 3 is. Is n and the maximum effective diameter for image formation on the output phosphor screen 5 is S, the inner diameter D of the mask is
Is desired to have a size that approximately satisfies [S + T (LS) / (2nf)].

Further, at least the surface of the mask 9 is preferably such that the reflected light from the optical lens 7 is not reflected or scattered again. Since it is considered that light reaches the mask 9 from various directions, the antireflection coating is not effective. Therefore, a black substance with almost no gloss on the surface is suitable. As a specific example, for example, a black plastic material having fine irregularities without polishing the surface, or a metal material having the surface painted or baked in black is suitable.

[0014]

As described above, according to the present invention, of the reflected light from the optical lens in the output window of the X-ray fluorescence multiplier, re-incident light to the output window is suppressed as much as possible, and It is possible to prevent a decrease in contrast

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing the vicinity of an output window of an X-ray fluorescent multiplier according to an embodiment of the present invention.

FIG. 2 is a schematic diagram showing the dimensional relationship of FIG.

FIG. 3 is a schematic cross-sectional view showing a conventional general X-ray fluorescence multiplier device.

FIG. 4 is a sectional view showing the vicinity of an output window of a conventional X-ray fluorescence multiplier.

[Explanation of symbols]

 1 ... Vacuum envelope 3 ... Output window 5 ... Output fluorescent screen 7 ... Optical lens 9 ... Mask

Claims (3)

[Claims] 1. An X-ray fluorescent multiplier having an output fluorescent screen for converting an electron image into a visible light image inside an output window in a vacuum envelope, and an output window of the X-ray fluorescent multiplier. In an X-ray fluorescence multiplier device including an image reproducing device having an optical lens disposed near the optical window, a mask for preventing reflected light incident from the optical lens surface is attached to the outside air side of the output window. Characteristic X-ray fluorescence multiplier device. 2. The X-ray fluorescence multiplier tube apparatus according to claim 1, wherein the inner diameter of the mask is in a range that does not prevent the visible output light from the output fluorescent screen from entering the lens. 3. The X-ray fluorescence multiplier tube apparatus according to claim 1, wherein at least the surface of the mask is made of a black material that reflects and scatters less light.