JPS5946878A - Radiation measuring element - Google Patents

Abstract

PURPOSE:To eliminate electromagnetic induction and to provide an excellent insulation characteristic with respect to signal transmission and to prevent the radiation damage and deterioration of an image pickup tube and an image pickup element with respect to image processing for the space distribution of radiations, by adding a fluorescent material to the core part of an optical fiber cable and uniting a scintillator and the optical fiber cable to one body. CONSTITUTION:A material which emits fluorescent when exposed to radiations is added to a scintillator core 1 and therefore said core emits fluorescence by the mutual effect with the radiations. The fluorescence is scattered several times by the specular surface of a silver film coating 4 and is then propagated to a core 1' of an optical fiber cable after E-E'. The fluorescence emitted near the focus advances straightforward as the refractive index of the core 1 before C-C' is uniform in refractive index. This fluorescence is reflected by the specular surface of the coating 4. Since the specular surface is parabolic, the reflected light is parallel with the central axis. In other words, all the fluorescence emitted near the focus are the rays incident perpendicularly to the C-C' section in the part C-C'.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a radiation measuring element (2) that utilizes scintillation light emission.

[Technical background of the invention and its problems]

Normally, radiation detection using light detects radiation as light using a scintillator (fluorescent material), converts the light into photoelectrons with a photomultiplier tube, etc., and multiplies the secondary electrons. A method of obtaining an electrical detection signal is used. In measuring the spatial distribution of radiation using this method, in the case of X-rays, a scintillator and an imaging tube are combined to detect spatial radiation and perform image processing. However, in radiation measurement using the above measurement method, radiation information is transmitted using electrical signals, so if the noise environment of the device deteriorates due to electromagnetic induction, power lines, etc., there is a problem that measurement accuracy will also decrease. One way to avoid this problem is to use optical fiber cables (two-way optical transmission), but in that case, an electro-optical converter and a photo-electric converter are required, making information processing complicated.Especially in image processing of the spatial distribution of radiation. However, there remains the problem that image pickup tubes and solid-state image sensors are damaged and deteriorated by radiation.

Furthermore, there is currently no suitable measurement method for image processing of the spatial distribution of neutrons.

[Purpose of the invention]

The present invention has been made in view of the above circumstances, and there is no electromagnetic induction for signal transmission, and radiation damage and deterioration of the image pickup tube, image pickup element, etc. can be avoided in the case of insulation C:T leakage, IIIjI image processing of radiation spatial distribution, etc. The object of the present invention is to provide a radiation measuring element that can be applied to image processing of spatial distribution of neutron beams.

[Summary of the invention]

The present invention is a radiation measuring element in which a scintillator and an optical fiber cable are integrated by adding a fluorescent substance to the core portion of the optical fiber cable.

[Embodiments of the invention]

Hereinafter, a seventh embodiment of the present invention will be specifically described with reference to the drawings. The optical fiber cable shown here is distinctive in its tip core. In Figure 1, after section E-B',
It is a normal optical fiber cable, and has a cladding 2' surrounding the core 1', and sheathing scraps 3' covering these.
There is. Before the gg' part, the part corresponding to the optical fiber core 1' has a scintillator (fluorescent material).
There is an added scintillator core 1, and its shape is such that the diameter increases toward the tip, and the opposite is true before the c-c' portion.

Its diameter is formed to become smaller as it draws a parabola with A as its apex. This core 1 is equipped with a scintillator (fluorescent material) for the moon that normally constitutes the core of the optical fiber.
The outer surface of the clad 2, which corresponds to the clad 2' of the optical fiber cable, is mirror-finished and then coated with a silver film 4.

It is covered with the same coating layer 3 as the optical fiber cable.

The cross section and refractive index distribution of the above optical fiber cable are
Seen in the figure. Assuming that the refractive index distribution of the core 1' of the optical fiber cable is as shown in the HE' cross section (Fig. 2D), the cross section from E-E' to C-C' and c-
As shown in Figure 2 (Bl (B)'), the refractive index distribution between the c' groups corresponds to the diameter of the scintillator core 1, and in this distribution, the center of the core 1' in the original fiber cable The refractive index distribution is such that the ratio of the refractive index with the cladding 2' and the ratio of the refractive index between the center of the scintillator core and the cladding 2 are preserved.An example of such a refractive index distribution is shown in the fourth example. This is shown in Figure 4. In Figure 4, there is a situation in which a straight line is formed when 7 points with equal refractive index are connected.
It can be seen that the refractive index ratio mentioned earlier is conserved.

2) and (A') show the BB section and its refractive index, and FIG. 2 (C) and (C') show the DD' section and its refractive index.

In this manner, the radiation measuring element according to the present invention can be applied to spatial distribution measurement in the state shown in FIG. 3 by configuring it in a configuration in which the number of elements is reduced.

The radiation measurement element operates as follows in radiation measurement. Since the scintillator core 1 is doped with a substance that emits fluorescent light when exposed to radiation (fluorescent substance), the scintillator core 1 emits fluorescent light 7 due to interaction with the radiation. After this fluorescent light is scattered several times by the mirror surface of the silver film coating 4, the E-B
' propagates to the subsequent core 1' of the optical fiber cable. Here, in order to explain YM single (2), we will explain the fluorescence emitted near the focus of the parabolic mirror surface before C-C'E+5.3, the fluorescence emitted near the focus will be explained before C-C' Since the refractive index of the scintillator core 1 is uniform, it travels straight and is reflected by the mirror surface of the silver film coating 4. Since this mirror surface is a parabola, the reflected light becomes parallel to the central axis. In other words, the fluorescent light emitted near the focal point becomes a ray of light that is incident perpendicularly to the C-C' section at the C-C' section.From the c-c' section, the optical fiber cable (E-g
Up to part 1, the refractive index distribution is as shown in Figure 2, but here, as an example, as shown in Figure 4, a line connecting dots with equal refractive index is a straight line. From, c-
The fluorescent light beam incident perpendicularly to the cross section c' propagates to the core 4' of the optical fiber cable through an optical path Z as shown in FIG. The propagation of light in optical fiber cables is generally well known, so I will not explain it here, but the fluorescence that propagated through the original fiber cable is detected as an electrical signal using a suitable photoelectric converter, and is used for radiation measurement. Achieve.

Note that the idea of the present invention is not limited to the embodiment shown in FIG.
This also includes the modifications shown in the figures. No. 5N is an example of a shape in which two parts from e-c' in Fig. 1 are combined,
Fluorescent light emitted within the scintillator core 1 propagates through two optical fiber cables Z and is detected.

These two detection signals can be used for coincidence (simultaneous) d1 measurement, etc. Moreover, FIG. 6 is an example in which the modification of FIG. 5 is extreme, and the operation is the same.

Furthermore, the shape of the scintillator core is not limited to one embodiment, and can of course take any shape as long as the ratio of refractive index is maintained.

The core of an optical fiber cable is generally made of quartz lath, but it is also possible to use plastic, and the scintillator core is usually a glass scintillator made of lydium-6 or lydium-7, or a plastic scintillator. Considering the existence of fluorophore, it is thought that it would be easy to make it by adding a fluorescent substance to the same material as the optical fiber cable core. In addition, in one embodiment of the present application, it is described that only one type of scintillator is added, but the invention is not limited to this. For detection of different nuclides, scintillators Z with different characteristics, multiple layers, or different distributions may be added. It may be implemented with some modifications.

〔Effect of the invention〕

According to the present invention, since the scintillation light emitted from radiation detection can be directly transmitted using the optical fiber cable 7, the following effects can be obtained.

(1) Compared to conventional electrical signal transmission methods, electromagnetic induction
Noise from the 1117N line? I don't accept it.

(2) It is economical because it does not require a converter for the light r that is required in the case of optical transmission using an optical fiber cable in the conventional method.

(3) When used for IIIjl image processing for radiation spatial distribution measurement, radiation? The measurement location and the imaging device can be separated from each other, and damage and deterioration of the solid-state imaging device due to radiation can be avoided.

(4) Depending on the type, scintillators can emit X-rays,
Because it interacts with radiation such as neutrons and emits scintillation, it can be used for image processing of the spatial distribution of neutrons, etc.
Applications will be expanded to areas that were previously impossible.

[Brief explanation of the drawing]

Figures 1 (, A) and (B) show one embodiment 7 of the present invention.
/ cross-sections and their refractive index distribution 7; FIG. 3 is a side view showing a focused arrangement 7 of the element according to the invention for image processing; FIG. 4 is an enlarged side view showing the propagation of fluorescence. Figure 5 (AJ (B) and Figure 6 (AJ (B+ are different embodiments) It is a -v'' side view. 1゛°Scintillator core, 1'... Core of optical fiber cable, 2... Clad 2/-,... Clad, 3... Covering layer, 3'... ...Covering layer, 4...Shimei coating. Applicant's representative Patent attorney Takehiko Suzue Figure 1 (A) (B) Figure 3 Figure 2 (A) (A') (B) CB' ) Kazuo Wakasugi, Commissioner of the Japan Patent Office, 1977, Patent Application No. 157566/1983, 2, Title of the invention: Radiation measuring device 3, Person making the amendment, Relationship with the case, Patent applicant (307) Tokyo Shibaura Electric Co., Ltd. 4, Agent Address: 17th Mori Building, 1-26°5, Toranomon, Minato-ku, Tokyo Address: 105 Telephone: 03 (502) 3181
(Oshiro! November 30, 1981 6, Correct contents subject to amendment (1) "Diagram D" on page 4, line 1 O of the specification is corrected to "Diagram G." (2) ) "Figure 2 (11) CB" on page 4, line 12 of the specification
) J should be corrected as “Figure 2 (oL(n) J). (3) In the second line of page 5 of the specification, [Figure 2 (A). Figure 2 (AL([3)J). (4) In the second line of page 5 of the specification, "Figure 2 (C). (0') J" should be changed to "Figure 2 (E) t. (F)J
I am corrected. (5) "Figure 2 (A) t(A')... Diagram showing distribution" from line 9 of page 9 of the specification to line 12 of the same page
Correct the statement as follows. "Figure 2 (A) and (B) are 13- in Figure 1 (A)
B' cross-sectional view and its refractive index distribution diagram, Figure 2 (0) t
(D) is a c-c' cross-sectional view and its refractive index distribution diagram in factor l (A), and Figures 2 (E) and (F) are Figure 1 (A).
) and its refractive index distribution diagram, Figure 2 (G) t (H) is E-E in Figure 1 (A).
'Cross-sectional view and its refractive index distribution map' (5) Figure 2 of the drawing is as attached (with two corrections).

Claims (1)

[Claims] A radiation measuring element characterized in that a scintillator and an optical fiber cable are integrated by adding a fluorescent substance to the core portion of the optical fiber or optical fiber cable.