JPH06331748A - Scintillator and fabrication thereof - Google Patents

Abstract

PURPOSE:To provide a scintillator, and fabrication method thereof, in which the quantity of light to be emitted from a light emitting element is made uniform by eliminating the positional dependency therefrom. CONSTITUTION:The scintillator 1 is fabricated by coating a predetermined range on the surface of a light emitting element 2 made of a mirror finished CsI crystal, for example, with a thin film 3 on which a region for regulating the quantity of light is formed by black stripes 4, for example. The fabrication method of the scintillator comprises a step for mirror finishing the surface of the light emitting element 2, and a step for coating a predetermined range on the surface of the light emitting element 2 with a thin film 3 on which a region for regulating the quantity of light is formed by black stripes 4, for example.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scintillator and its manufacturing method. More specifically, the present invention relates to a scintillator in which the position dependency of the amount of light is reduced and a method for manufacturing the scintillator.

[0002]

2. Description of the Related Art Conventionally, in measuring radiation, as shown in FIG. 3, radiation energy is converted into a quantity of light by a scintillator 11 and converted into an electric signal amplified by a photomultiplier tube 12, Counter 13 and multiple wave height analyzer 1
The method of inputting in 4 is adopted. This scintillator 1
For the light emitting element in 1, a crystal such as CsI (pure) or CsI (Tl) is used.

However, since the amount of light emitted from this light emitting element has a position dependency due to the crystalline state, even if radiation of the same energy is incident, the amount of emitted light differs depending on the incident position. Therefore, even if radiation of the same energy is incident, the measurement value will differ depending on the detection position. Therefore, by applying sandpaper to the crystal surface of the region where the amount of emitted light is small (see the shaded area in FIG. 4), light scattering in that region is increased and the amount of emitted light is made uniform.

However, when sandpaper is applied to the crystal surface, the crystal size may change and the light emitting characteristics of the light emitting element may change. Also, if you apply too much sandpaper, you can not return to the original surface state,
The work needs to be done carefully and gradually. for that reason,
Uniformizing the amount of light emitted from a light emitting element is an extremely complicated task.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and the light emission amount is made uniform by eliminating the position dependency of the light emission amount of the light emitting element. It is intended to provide a scintillator and a manufacturing method thereof.

[0006]

A scintillator of the present invention is characterized in that a light-emitting element having a mirror-finished surface is covered with a thin film having a light amount adjusting region formed on a predetermined area of the surface.

In the scintillator of the present invention, it is preferable that the light amount adjusting region is formed by a light absorbing stripe such as a black stripe or a yellow stripe.

Further, in the scintillator of the present invention,
The thin film is preferably a polyethylene terephthalate film having Al deposited on both sides.

On the other hand, the manufacturing method of the scintillator of the present invention is
It is characterized in that it includes a procedure of mirror-finishing the surface of the light emitting element and a step of coating a thin film having a light amount adjusting region formed on a predetermined area of the surface of the light emitting element.

In the method of manufacturing a scintillator of the present invention, it is preferable that the light amount adjusting region is formed by a light absorbing stripe such as a black stripe or a yellow stripe.

Further, in the method for producing a scintillator of the present invention, it is preferable that the thin film is a polyethylene terephthalate film having Al deposited on both sides.

[0012]

Since the scintillator of the present invention is constructed as described above, the position dependency of the light emission amount is eliminated and a uniform light emission amount can be obtained. Further, since the light emission amount is adjusted by simply coating the mirror-finished light emitting element with a thin film, the dimensional accuracy is high and the characteristics are uniform.

On the other hand, according to the scintillator manufacturing method of the present invention, it is possible to obtain a scintillator in which the position dependency of the light emission amount is eliminated by a simple operation. Further, even when the uniform light emission amount cannot be obtained by the first adjustment, the readjustment can be performed only by replacing the thin film in which the light adjustment region is formed.
Therefore, the scintillator can be manufactured with high yield.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described based on embodiments with reference to the accompanying drawings, but the present invention is not limited to such embodiments.

FIG. 1 is a schematic view of a scintillator according to an embodiment of the present invention, and FIG. 2 is a sectional view of the scintillator. In the figure, 1 is a scintillator, 2 is a light emitting element, 3 is a polyethylene terephthalate film (Mylar) having Al deposited on both sides, 4 is a light absorbing stripe (black stripe), and 5 is a photomultiplier tube.

In the embodiment of the present invention shown in FIGS. 1 and 2, a quadrangular prism CsI (pure) crystal is used as the light emitting element 2. The surface of the light emitting element 2 is mirror-finished so that the amount of emitted light is not affected by the state of the crystal surface. This mirror-finished surface is covered with mylar 3 as shown in FIG. Note that FIG.
In, the thickness of mylar 3 is exaggerated. As shown in FIG. 1, light absorption stripes 4 having a predetermined width are provided at predetermined intervals in a predetermined range of the mylar 3.
Examples of the light absorbing stripes include black stripes and yellow stripes. In FIG. 2, the light-absorbing stripe 4 has a width of 2 mm and a pitch of 10 mm within a range of 120 mm from the connection end with the photomultiplier tube 5.
It is provided in. The range, width, and pitch of the light absorbing stripes 4 are not limited to these, and may be appropriately selected according to the size of the light emitting element 2, variations in the amount of emitted light, and the like.

Next, a method of manufacturing the light emitting element 2 having such a structure will be described.

Step 1: The CsI (pure) crystal surface is polished and mirror-finished to obtain a light emitting element 2.

Step 2: The mylar 3 is adjusted according to the crystal size of the light emitting element 2.

Step 3: Form light absorbing stripes 4 in a predetermined area of the mylar 3 with a predetermined width and a predetermined pitch. The light absorbing stripes 4 are formed using, for example, magic ink.

Step 4: The mylar 3 is wound around the surface of the light emitting element 2 with the surface on which the light absorbing stripes 4 are formed facing inward so that the light absorbing stripes 4 come to a predetermined position.

Next, the light emission characteristics of the scintillator 1 having the light absorbing stripes 4 formed thereon were investigated.

Example 3 A scintillator 1 was manufactured by the above-mentioned manufacturing method using a CsI (pure) crystal having a side length of 35 mm and a length of 300 mm. The black stripes 4 were formed within a range of 120 mm from the connection end of the photomultiplier tube 5, the width was 2 mm, and the pitch was 10 mm. The change in the amount of light in the longitudinal direction of this scintillator 1 was measured, and the results are shown in Table 1.
It was shown to.

Comparative Example For comparison, a scintillator was produced in the same manner as in Example except that the black stripe was not formed. The change in the amount of light in the longitudinal direction of this scintillator was measured, and the results are also shown in Table 1.

[0025]

[Table 1]

From Table 1, it can be seen that the light emission amount of the scintillator of the example is more uniform than that of the scintillator of the comparative example.

In this embodiment, CsI (pure)
However, the present invention can be favorably applied to other scintillation materials.

Further, in the present embodiment, the black stripes and the yellow stripes are used as the light absorbing stripes, but blue stripes, red stripes, purple stripes, green stripes and the like can also be used favorably.

[0029]

As described above, according to the scintillator of the present invention, the light emission amount can be made uniform. Further, since it is formed by coating the mirror-finished surface with a thin film, its dimensional accuracy is good and there is no variation among products. Therefore, the characteristics of the product are homogenized. Therefore, it is possible to manufacture a radiation measuring apparatus having stable characteristics.

On the other hand, according to the scintillator manufacturing method of the present invention, it is possible to manufacture a scintillator having a uniform light emission amount by a simple operation. Further, since the light emission amount is made uniform by the thin film in which the light adjustment region is formed, it is easy to adjust the light emission amount. Moreover, the readjustment of the amount of light emission can be achieved simply by replacing the thin film, and since it is not necessary to replace the light emitting element itself, the light emitting element can be manufactured with high yield. Therefore, the manufacturing cost of the light emitting element can be reduced.

[Brief description of drawings]

FIG. 1 is a schematic diagram of an embodiment of a scintillator of the present invention.

FIG. 2 is a sectional view of the same embodiment.

FIG. 3 is an explanatory diagram of a radiation measuring apparatus.

FIG. 4 is an explanatory diagram of a conventional light emitting element.

[Explanation of symbols]

 1 scintillator 2 light emitting element 3 mylar 4 light absorbing stripe, black stripe 5 photomultiplier tube

Claims (4)

[Claims] 1. A scintillator comprising a mirror-finished light emitting element, and a thin film having a light amount adjusting region formed on a predetermined area of the surface of the light emitting element. 2. A method for manufacturing a scintillator, comprising: a step of mirror-finishing the surface of the light emitting element; and a step of coating a thin film having a light amount adjusting region formed on a predetermined area of the surface of the light emitting element. . 3. The method of manufacturing a scintillator according to claim 2, wherein the light amount adjusting region is formed by a light absorbing stripe. 4. The method for producing a scintillator according to claim 2, wherein the thin film is a polyethylene terephthalate film having Al deposited on both sides.