JPH04134090U - radiation detector - Google Patents

Abstract

(57) [Summary] [Purpose] The purpose is to provide a radiation detector with excellent detection ability that efficiently detects weak radiation. [Structure] A light-shielding film that blocks X-ray incident light is provided on one side of a shielding box that shields radiation. A phosphor screen 8 having a sawtooth cross section is provided inside the shielding box, and a photomultiplier 7 is disposed at a position where the light receiving surface faces each of the phosphor screens 8. In this way, by increasing the area of the phosphor screen 8, the amount of fluorescence when irradiated with X-rays increases, and by arranging the phosphor screen 8 facing the light receiving surface of the photomultiplier 7, it is possible to increase efficiency. Since fluorescence is incident on the light receiving surface, even weak incident X-rays can be detected.

Description

[Detailed explanation of the idea]

[Purpose of invention]

0001

[Industrial application field]

The present invention relates to a radiation detector that detects radiation.

0002

[Conventional technology]

There is an X-ray detector as shown in FIG. 2 as a conventional radiation detector. X-rays pass through However, the X-rays 2 enter the X-ray detector 3 through the light-shielding film 1, which does not allow light to pass through. When the phosphor hits the phosphor screen 5 coated with the phosphor, the phosphor emits fluorescence 6. This fluorescence 6 is detected by the photomultiplier 7, which is a photodetector, and converted into an electrical signal. Therefore, the X-ray dose can be measured. Generally, X-ray detectors are required to have the ability to detect weak X-rays; When the intensity becomes weaker, the fluorescence emitted from the phosphor screen also becomes weaker. Therefore, the detection ability depends on how efficiently this fluorescence can be detected by the photodetector. I will do it.

0003

[Problem that the idea aims to solve]

Conventional X-ray detectors have phosphors arranged in a flat manner, so the fluorophore inside the X-ray detector When a photodetector captures the fluorescence emitted from a light object, there are many blind spots. There was a problem.

0004 When capturing fluorescence emitted from a phosphor, the fluorescence is placed at right angles to the light receiving surface of the photodetector. The closer the incident angle is to the phosphor screen, the more efficiently it will be captured. However, if it is installed in such a position, it may block the incident X-rays. There was a problem.

[0005] In addition, in order to increase the amount of fluorescence detected by the photodetector, it is necessary to increase the area of the fluorescent screen. You could think so. However, even if the phosphor screen is simply expanded, the distance from the photodetector is still long. As the number of surfaces increases, the density of the incident X-ray flux becomes sparse, making it difficult to achieve sufficient effect. There was a problem.

[0006] Therefore, the purpose of this invention is to position the fluorescent screen at an angle that faces the light-receiving surface of the photodetector as much as possible. Provides a radiation detector that can be installed at 300 degrees and has an increased fluorescent screen area. It is. [Structure of the idea]

[0007]

[Means to solve the problem]

In order to achieve the above purpose, in the radiation detector, a concave surface with an inclination is used on the phosphor screen. It has a photodetector with a convex surface and a light-receiving surface located opposite the slope of the concave and convex surface. It is characterized by:

[0008]

[Effect]

By creating irregularities on the phosphor screen, the surface area of the phosphor screen increases and radiation can be captured. Increase efficiency. In addition, the fluorescent screen is placed close to the angle facing the light-receiving surface of the photodetector. Therefore, the photodetector can efficiently detect fluorescence.

[0009]

【Example】

Embodiments of the present invention will be described with reference to the drawings.

0010 As shown in Figure 2, when 8 is irradiated with X-rays 2, it emits fluorescence, that is, it emits X-rays. This is a fluorescent screen that converts light into light, and its surface has a sawtooth-like unevenness in cross section. It is being The shape of this unevenness is such that the surface area of the phosphor screen 8 is maximized, and The angle between the fluorescent screen 8 and the light receiving surface of the photomultiplier 7, which is a photodetector, is formed. (that is, both sides are parallel). from the fluorescent screen The concave and convex shape is such that the emitted fluorescence 6 is not blocked by the convex portion. The shape of these irregularities is determined based on the emission distribution characteristics of the fluorescent screen 8 with respect to incident X-rays. The position of the photomultiplier 7, which is a photodetector, is determined in accordance with the mounting direction.

[0011] By forming the phosphor screen 8 with unevenness to satisfy the above conditions, Therefore, by increasing the surface area of the phosphor screen 8, the light emitting surface becomes wider and the photodetector The amount of light incident on the photomultiplier 7 increases. In other words, the X-ray trapping effect rate goes up. The degree to which the fluorescent screen 8 faces the light receiving surface of the photomultiplier 7 As the size increases, the photomultiplier 7 efficiently uses the light emitted from the phosphor screen. can be caught.

0012

[Effect of the idea]

According to the present invention, by increasing the surface area of the fluorescent screen of the radiation detector, the light emitting surface can be made wider, increasing the amount of light incident on the photodetector.

[0013] Also, the degree to which the fluorescent screen can be placed opposite the light-receiving surface of the photodetector is increased. Therefore, the amount of light incident on the photodetector increases. Therefore, it can efficiently capture weak radiation. can do. Therefore, a radiation detector with excellent detection sensitivity can be provided.

[Brief explanation of drawings]

FIG. 1 is a structural diagram of an X-ray detector according to an embodiment of the present invention.

FIG. 2 is a structural diagram of a conventional X-ray detector.

[Explanation of symbols]

1... Light shielding film, 2... X-ray, 3... X-ray detector, 4... Shielding box,
5... Fluorescent screen, 6... Fluorescent, 7... Photo multiplier, 8
...Fluorescent screen.

Claims (1)

[Scope of utility model registration request] Claim 1: A shielding box for shielding radiation; a radiation incident surface provided in a part of the shielding box; a phosphor screen having an inclined uneven surface provided inside the shielding box; and the phosphor screen. A radiation detector comprising: a photodetector having a light-receiving surface at a position opposite to the uneven surface of the radiation detector;