JP2000266855A - Radiation detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radiation detector which can measure an energy and an intensity of electromagnetic radioactive rays and charged particles radiated from an object of a finite volume and can measure with covering wide solid angles. SOLUTION: In a semiconductor detector which can detect an intensity of electromagnetic radioactive rays and charged particles, separate detector elements are arranged in an array. A plurality of the arrays 1 not smaller than three are arranged on a bendable film 2a via a space enabling the bending. When the film 2a is bent to form a cylinder, the photodiode arrays 1 form an (m)-angular prism having one side of a breadth of the array. In the case of radioactive rays emitted in all directions from a sample to be measured such as fluorescent X rays, while the sample to be measured is preferably covered completely with the detector to efficiently detect the radioactive rays, forming this (m)-angular prism can cover all directions in two dimensions, so that a detection efficiency is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radiation detector capable of two-dimensionally or three-dimensionally detecting the amount and energy of electromagnetic radiation and charged particles at a wide solid angle, and more particularly to efficiently detect weak fluorescent X-rays. It is preferably used for material analysis that needs to be detected.

[0002]

2. Description of the Related Art Conventionally, there are the following two-dimensional radiation detectors.

[0003] One of them is p as shown in FIG.
An n-junction type silicon photodiode is arranged in an array as shown in FIG. 5A (referred to as a first conventional example).

In the first conventional silicon photodiode, a p-type epitaxial layer 18 and an n-type doped layer 19 are formed on a silicon substrate 17, and an insulating oxide film 20, an electrode 21, and a back electrode 22 are formed. And can detect radiation in a wide energy range with high efficiency. By arranging them on a substrate 16 as an array 14 and independently driving them via signal wirings 15 from the individual elements, it is possible to measure the two-dimensional intensity distribution of the radiation flux. However, a photodiode generally has no energy resolution because a depletion layer for collecting radiation energy is thin and cannot collect all radiation energy. Therefore, in the detector as shown in FIG.
There is a problem that the energy spectrum cannot be measured even though the line can be detected.

Assuming that the limitation on the energy resolution described above has been solved and the solid angle at which the radiation to be detected is taken into the detector has been increased, a semiconductor radiation detector element having an energy resolution as shown in FIG. There is a case where a plurality of cases are housed in a case-like housing (referred to as a second conventional example).

The detectors shown in FIG. 6 each have a thick p-depletion layer.
Semiconductor detector element 23 made of germanium single crystal having in-junction or silicon single crystal drifting lithium
And a pair of amplifiers 24 for amplifying a signal therefrom are used as a detection unit, and such a detection element is used as a liquid nitrogen container 25.
In this case, several to a dozen or more pieces are housed in a concave housing 26 integrated with the above. It is known that this type of semiconductor detector has excellent energy resolution. By arranging a plurality of detection elements in a concave shape, the entire detector attempts to maximize the solid angle that can see the object to be measured. It is.

[0007]

However, in the apparatus shown in FIG. 6, since cooling with liquid nitrogen is required, the installation conditions of the detector are limited, and periodic replenishment of liquid nitrogen is required. In addition, since the number and shape of the detection elements are also limited, the solid angle in which the object to be measured is viewed is limited.

On the other hand, the necessity of measurement, such as the detection of extremely weak fluorescent X-rays from trace elements, is increasing, and when a detector having a small solid angle as described above is used,
There is a problem that it takes a long time for material evaluation. Further, there is a problem that maintenance is troublesome such as replenishment of liquid nitrogen.

The present invention has been made in order to solve the above problems.
To provide a radiation detector that can measure the energy and intensity of electromagnetic radiation and charged particles emitted from an object having a finite volume, and that can perform measurement covering a wide solid angle. Aim.

[0010]

In order to achieve the above object, a radiation detector according to the present invention comprises an array of individual detector elements, and a plurality of the arrays arranged on a bendable film. It is characterized by being arranged with an interval capable of bending.

Further, the radiation detector of the present invention is characterized in that individual detector elements are arranged in a matrix, and a plurality of the matrices are arranged on a bendable film at a bendable interval. Is what you do.

Further, the present invention is characterized in that the film is cylindrically curved at a curvature determined by the array width and the arrangement interval, and the substance to be detected is disposed therein.

The present invention is also characterized by having detector elements arranged in a matrix above and below the cylinder.

Further, the present invention is characterized in that the film is folded into a polyhedron determined by the shape and number of these matrices, and the substance to be detected is disposed therein.

Further, with respect to the photodiode array or the photodiode matrix, energy sensitivity can be changed by forming metal films having different thicknesses on the surface of each element, and signals from each element can be detected independently. It is characterized by.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 A first embodiment of the present invention will be described with reference to the drawings.

FIG. 1 shows the configuration of the first embodiment. In the present embodiment, an array 1 in which n pieces of the above-described silicon photodiode elements are arranged is formed into a bendable film 2.
m (three or more) are arranged on a. The film is insulating, and the electrodes of each array are wired independently. The arrays are arranged at appropriate intervals so that they can be bent without being in close contact with each other. When such a film is bent to form a cylinder, each photodiode array forms an m-shaped prism whose width is one side of the array. In the case of radiation emitted from the sample to be measured in all directions, such as fluorescent X-rays, it is desirable to completely cover the sample to be measured with a detector in order to detect it efficiently. When formed, it becomes possible to cover all directions two-dimensionally, and the detection efficiency is improved. For example, if the sample to be measured is placed at the center of a cylinder having the same diameter and height, the effective detected solid angle is about 70% of the total solid angle. In addition, an m of the same size as the bottom is placed above and below such an m prism.
With a square silicon photodiode matrix,
The sample to be measured can be completely covered with the detector.

Embodiment 2 FIG. 2 is an explanatory diagram showing a configuration of a second embodiment. In the present embodiment, the aforementioned silicon photodiode is m
As shown in the figure, k (four or more) matrices 3 in which n rows are arranged are arranged on a bendable film 2b.
The film is insulative, and the electrodes of each matrix are wired independently. Further, the respective matrices are arranged at appropriate intervals without being tightly attached so as to be bendable. The shape and number of the matrix are regular triangles (k = 4,
8, 20), square (k = 6) or regular pentagon (k =
In the case of 12), when such a film is bent, a regular k-plane can be formed. In the case of a triangle, a polyhedron other than a regular polyhedron can be formed when k = 6 and 10. In this case, if the sample to be measured is placed therein, the detector can completely cover the sample to be measured, and ideal detection efficiency can be obtained. In the case where an incident probe is required, such as X-ray fluorescence, a probe insertion hole may be provided in a part of the regular k-plane.

Third Embodiment FIG. 3 is an explanatory diagram showing a configuration of a third embodiment. In this embodiment, silicon photodiodes whose cross-sectional views are shown in FIG. 3B are arranged as n arrays as shown in FIG.

In the silicon photodiode, a p-type epitaxial layer 8, an n-type doped layer 9, an oxide film 10, an electrode 11, and a back electrode 12 are formed on a silicon substrate 7, and a portion of the oxide film 10 which receives radiation is formed. A metal film 13 is provided thereon. In such a configuration, part or most of the radiation incident on the light receiving surface of the silicon photodiode element is absorbed by the metal film 13 formed on the surface of the light receiving surface so as not to contact the electrode 11. The degree of absorption depends on the type and thickness of the metal film and the type and energy of radiation. For example, when X-rays are incident on 1 μm aluminum, the degree of absorption by the X-ray energy is as shown in FIG. different. Therefore, the sensitivity of the element provided with this film to X-rays having an energy of 0.3 keV or less can be ignored as compared with the element provided with no metal film. Therefore, an X-ray intensity of 0.3 keV or more can be obtained by taking the difference between the two intensities. By changing the thickness and material of the metal film of each element, the sensitivity of the element to X-ray energy can be changed. By arranging n such elements and taking the difference in their intensities, n steps X-ray intensity corresponding to this energy can be obtained.

[0021]

As described above, according to the present invention, the detection efficiency of radiation emitted from the sample to be measured in all directions is greatly improved, and the material analysis time can be reduced and the analysis of minute and minute samples can be performed. become.

In general, a radiation detector having energy resolution can be obtained by using an array of photodiodes having no energy resolution.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a first embodiment.

FIG. 2 is a configuration diagram illustrating a second embodiment.

FIG. 3 is a configuration diagram illustrating a third embodiment.

FIG. 4 is a diagram illustrating energy characteristics of a radiation detector according to a third embodiment.

FIG. 5 is a configuration diagram showing a first conventional example.

FIG. 6 is a configuration diagram showing a second conventional example.

[Explanation of symbols]

1,4,14 silicon photodiode array, 2
a, 2b film, 3 silicon photodiode matrix, 5, 15 signal wiring, 6, 16 substrate, 7,
17 silicon substrate, 8,18 p-type epitaxial layer, 9,19 n-type doped layer, 10,20 oxide film,
1,21 electrode, 12,22 back electrode, 13 metal film, 23 semiconductor detector counter tube, 24 amplifier, 25
Liquid nitrogen container, 26 housing, 27 silicon photodiode.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Hiroshi Kurokawa 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Mitsubishi Electric Corporation F-term (reference) 2G088 EE29 FF03 GG21 HH08 JJ01 JJ04 JJ05 JJ08 JJ30 JJ37 KK29 4M118 AA01 AB04 BA06 CA03 CA19 CB14 GA10 HA24 HA27 5F049 MA02 MB03 QA14 RA03 SS03 WA07 5F088 AA02 AB03 EA02 EA13 GA04 LA07

Claims (6)

[Claims] In a semiconductor detector capable of detecting the intensity of electromagnetic radiation or charged particles, individual detector elements are arranged in an array, and the array is bent into three or more plural pieces on a bendable film. A radiation detector, wherein the radiation detectors are arranged with an interval possible. 2. In a semiconductor detector capable of detecting the intensity of electromagnetic radiation or charged particles, individual detector elements are arranged in a matrix, and the matrix is bent over four or more flexible films. A radiation detector, wherein the radiation detectors are arranged with an interval possible. 3. The radiation detector according to claim 1, wherein the radiation detector is curved in a cylindrical shape with a curvature determined by the array width and the arrangement interval, and the substance to be detected is arranged therein. 4. The radiation detector according to claim 3, further comprising detector elements arranged in a matrix above and below the cylinder. 5. The radiation detector according to claim 2, wherein the film is folded into a polyhedron determined by the shape and the number of the matrix, and the substance to be detected is disposed therein. 6. The energy sensitivity is changed by forming metal films having different thicknesses on the surfaces of the individual detector elements, and a signal from each detector element can be independently detected. Item 6. A radiation detector according to any one of Items 1 to 5.