JP4134993B2 - X-ray detector - Google Patents

Description

The present invention is an X produced using a scintillator powder that absorbs X-ray energy and emits light.
The present invention relates to a line detector and an X-ray detection apparatus.

A scintillator that emits light by absorbing X-ray energy is used in an X-ray detector (hereinafter referred to as a detector) of an X-ray detector (hereinafter referred to as a detector). Such a detector measures the amount of X-rays by converting the light emitted from the detection body into a current using a photodetector such as a photodiode. Since the emission intensity and emission wavelength of the detector depend on the scintillator material, it is necessary to select an appropriate material according to the application.

Examples of scintillators that detect X-rays include ceramics such as Gd ₂ O ₂ S and CdWO ₄ . In ceramic scintillators, raw material powders are made into bulk by sintering such as hot pressing or HIP, or by single crystallization such as Czochralski method. Ceramic scintillator detectors have strong emission intensity with respect to X-ray irradiation and can detect X-rays with high sensitivity, and are therefore used in many medical devices including X-ray CT apparatuses.

Ceramic scintillators absorb X-ray energy and emit light even in a powder state. Utilizing this property, ceramic scintillator powder (hereinafter referred to as scintillator powder)
Patent Document 1 and Patent Document 2 disclose that a detection body is produced from a mixed material of resin and resin.

JP2001-1888085 JP 2004-325178 A

Patent Document 1 is an example in which a detection body made of a mixed material composed of scintillator powder and an epoxy resin is used in an X-ray detection apparatus. By reducing the difference in thermal expansion between the optical coupler and the detection body, it is said that peeling at the interface between the optical coupler and the detection body is prevented.

Patent Document 2 is an example in which a detection body is formed from a mixture of scintillator powder and resin on a plurality of photodiodes arranged in a matrix. By adding a dispersing material to the mixed material, it is possible to uniformly fill the scintillator powder, and to reduce luminance unevenness of the radiation detecting device.

Even if an attempt is made to produce a detection object having a large area and a single object by sintering, a detection object larger than the processing chamber of the sintering apparatus cannot be produced. If a detection body is made of a mixed material composed of scintillator powder and resin, a single body detection body can be easily manufactured with a large area by simply preparing a large mold.

The scintillator powder contains heavy metals such as Gd, Ga, and Bi. These heavy metals are relatively expensive, and at the same time, there are concerns about adverse effects on living bodies and the environment due to outflow. Therefore, it is preferable that the detection object contains as little heavy metal as possible. A detector produced from a mixture of scintillator powder and resin can be a detector that uses less scintillator powder and less heavy metal than a bulk.

However, simply reducing the amount of scintillator powder in order to reduce the amount of heavy metal contained in the detector, the emission intensity of the detector is greatly reduced, making it difficult to produce a detector with a high emission intensity. .

In view of the above problems, the present invention is capable of reducing the amount of scintillator powder containing heavy metal without greatly reducing the light emission intensity of the detection body, and the X using the detection body and the detection body.
A line detection apparatus is provided.

The detection device in the present invention is a detection body in which scintillator powder and a translucent resin are kneaded and cured.
And a detector for converting light into electricity, the filling degree of the scintillator powder changes substantially continuously in the thickness direction of the detector, and the filling degree A on the photodetector side is more than the filling degree B on the opposite side. Large, filling degree A
The ratio A / B of the filling degree B is preferably 1.1 or more and 5.0 or less.

Since the detection body made by mixing and curing the scintillator powder and the translucent resin is poured into a mold and solidified, the detection body material can be manufactured easily and inexpensively in a large area. The translucent resin used in the present invention is dissolved in a solvent and kneaded with scintillator powder to obtain a mixed material. The amount of the solvent can be adjusted as appropriate to make the viscosity easy to handle. Moreover, it is preferable that the mixed material of the scintillator powder and the translucent resin is previously subjected to defoaming treatment before curing to remove air entrainment. It is not preferable that air is caught in the detection body because emission intensity spots are generated on the detection body.

In the detection body of the present invention, the filling degree of the scintillator powder changes substantially continuously in the thickness direction of the detection body, and the filling degree A on the photodetector side that converts light into electricity is larger than the filling degree B on the opposite side. The emission intensity of the detection body is not greatly reduced. Compared with the part close to the photodetector, the light emitted from the scintillator powder at a remote part has a small contribution to the total amount of light received by the photodetector. By increasing the filling degree of the scintillator powder on the photodetector side, even if the opposite surface side is reduced, the emission intensity of the detection body does not decrease greatly. In addition, by continuously changing the degree of filling of the scintillator powder,
It can prevent that the hardening detection body becomes a distorted shape.

The degree of filling of the scintillator powder in the present invention indicates the percentage of the scintillator powder area in the observation area by observing the detected body tissue with a microscope or the like. For example, when the portion of the filling degree A is observed with a microscope and the area of the scintillator powder occupying the observation area is 50%, the filling degree A is 50%.
And The area percentage of the scintillator powder in the observation area is calculated by drawing vertical and horizontal grid lines on the micrograph of the detection object and counting the grids containing the scintillator powder. It goes without saying that the smaller the vertical / horizontal lattice spacing is, the more accurate the degree of filling can be calculated. Also, the series of operations may be calculated by image processing using a computer.

As a method of changing the degree of filling of the scintillator powder almost continuously from the photodetector side to the opposite surface side, for example, there is a method of curing the scintillator powder while settling in a permeable resin. Since the scintillator powder containing a heavy metal has a specific gravity larger than that of the light-transmitting resin, it easily settles in the light-transmitting resin, so that the filling degree can be changed almost continuously. Sedimentation may be allowed to stand naturally and settle by gravity, or may be caused to settle using forced acceleration, such as centrifugal force.
The change of the filling degree in the thickness direction of the detection body can be changed by the kind of the translucent resin, the curing temperature, and the like. Moreover, the change of the filling degree in the thickness direction of the detector can also be changed by adding a dispersing agent to the translucent resin.

When the filling degree ratio A / B of the scintillator powder is less than 1.1, it becomes close to a state in which the scintillator powder is contained almost uniformly in the detection body, and the amount of scintillator powder used cannot be reduced. On the other hand, when the filling degree ratio A / B exceeds 5.0, the emission intensity of the detector is greatly reduced, and the output from the photodetector is reduced, which is not preferable. Degree of filling A on the photodetector side in the detector of the present invention
The ratio A / B of the filling degree B on the opposite surface side is preferably 1.1 or more and 5.0 or less, and the more preferable filling ratio A / B is 1.5 or more and 3.0 or less. .

The scintillator powder in the present invention is Gd ₂ O ₂ S (hereinafter referred to as GOS) or
Gd ₃ Ga ₂ Al ₃ O ₁₂ (hereinafter referred to as GGAO) CdWO ₄ (hereinafter referred to as CWO), CsI (hereinafter referred to as CI), Bi ₄ Ge ₃ O ₁₂ (hereinafter referred to as BGO) The average particle size is preferably 10 to 100 μm.

The ceramic scintillator has a strong emission intensity with respect to X-rays and is a preferable material for the powder used in the detector of the present invention. GOS, GGAO, CWO, CI, and BGO are materials having high emission intensity in the visible light region. The ceramic scintillator powder may be a material obtained by subjecting a mixture of raw materials to primary firing and then water-washing or acid-washing, or may be obtained by re-pulverizing a powder that has been bulked by sintering or single crystallization. The method of finely pulverizing the bulk again to make a powder is a very preferable method in terms of resource reuse and cost because it can use the scrap material generated when processing the bulk material and the material that is no longer needed. . A ball mill or a stamp mill can be used for bulk pulverization. The particle size distribution of the scintillator powder is preferably a sharp distribution such as classification. The broad particle size distribution tends to cause uneven emission intensity on the detection body, and it is difficult to obtain a detection body with uniform emission intensity.

The average particle size of the scintillator powder in the present invention is a value measured with a laser particle size distribution analyzer. Increasing the average particle size can increase the emission intensity of the detection body. However, if the average particle diameter is too large, emission intensity spots tend to occur on the detection body. If the average particle size is reduced, the dispersion of the scintillator powder into the light-transmitting resin is improved, and unevenness in the emission intensity of the detection body is less likely to occur. However, reducing the average particle size is not preferable because it takes time and effort for pulverization and classification, and also causes adverse effects such as mixing of impurities due to pulverization for a long time, leading to a decrease in emission intensity. In order to obtain a detector with stable emission intensity, the scintillator powder preferably has an average particle size of 10 μm or more and 100 μm or less, and more preferably an average particle size of 10 μm or more and 50 μm or less.

The translucent resin in the present invention is preferably a resin having a light transmittance of 85% or more in a wavelength range of 450 to 650 nm. For example, epoxy, polyester, acrylic, silicone rubber,
A translucent resin such as vinyl can be used.

In the present invention, X-rays can be detected efficiently by setting the emission wavelength region of the detector within the spectral sensitivity range of the photodetector. The scintillator powder is preferably a material having high emission intensity in the visible wavelength region. In order to efficiently transmit the light emitted from the scintillator powder, the translucent resin is preferably a material that efficiently transmits light having a wavelength of 450 to 650 nm, which is a visible wavelength region. The light transmittance of the translucent resin is preferably 85% or more, and more preferably 90% or more.

The detector in the present invention preferably has an average filling degree in the thickness direction of the detector of 35% or more and 60% or less.

The average filling degree in the thickness direction of the detection body in the present invention is an average value obtained by cutting the detection body in the thickness direction and measuring the filling degree at equal intervals in the thickness direction from the filling degree A to the filling degree B. Say. Needless to say, the smaller the measurement interval, the more accurately the degree of filling can be calculated. Average filling degree is 35%
If it is less than the range, it is not preferable because the amount of scintillator powder contained in the detection body is small and the detection body has a low emission intensity. If the average filling degree exceeds 60%, the amount of the translucent resin is small and the detection body has a low mechanical strength, which is not preferable. In order to obtain a detector having sufficient light emission intensity and mechanical strength, the average filling degree is preferably 35% or more and 60% or less, and more preferably 45% or more and 60% or less.

The X-ray detection apparatus according to the present invention has a wavelength of 450 to 650 with a photodetector on the surface side of the scintillator powder with a large filling degree of the detector and a light reflecting material with a light reflectance of 80% or more on the surface side with a small filling degree.
It is preferably fixed with a translucent resin having a light transmittance of 85% or more in the range of nm.

A photodiode, CCD, or the like can be used for the photodetector. In particular, since the photodiode is small and inexpensive, it is a suitable photodetector for use in the X-ray detection apparatus of the present invention.

As the light reflecting material, a white light reflecting material such as TiO ₂ , Al ₂ O ₃ , or ZrO ₂ is preferably used. The light reflecting material can be a bulk or a mixed material of powder and resin. In particular, a light reflecting material made of rutile TiO ₂ is excellent in light reflecting efficiency and is a more preferable light reflecting material. The light reflectance of the light reflecting material is preferably 80% or more in order to increase the light receiving efficiency of the photodetector, and a more preferable light reflectance is 90% or more.

As the light-transmitting resin for fixing the detection body and the photodetector or the detection body and the light reflecting material, a resin whose main component is epoxy, polyester, acrylic, silicon, rubber, vinyl, or the like can be used. If the light-transmitting resin for fixing is made of the same material as the light-transmitting resin for the detecting body, the difference in thermal expansion between the detecting body and the light-transmitting resin for fixing becomes small, and the detecting body and the photodetector or the detecting body. And the light reflecting material can be prevented from peeling off. The fixing translucent resin, like the translucent resin of the detection body, preferably transmits light in the wavelength range of 450 to 650 nm efficiently, and preferably has a light transmittance of 85% or more.

In the detection device according to the present invention, a mixed material obtained by kneading scintillator powder and a translucent resin is applied and cured on a photodetector that converts light into electricity. Light scintillator powder and photodetector are integrated with translucent resin contained in the mixed material, and light reflection with a light reflectivity of 80% or more is provided on the side of the scintillator powder that is opposite to the photodetector with a small filling degree. It is preferable that a material is provided.

The detection device of the present invention can apply a mixed material obtained by kneading scintillator powder and a light-transmitting resin onto a photodetector and cure it to collectively produce a plurality of detectors. Since a plurality of detection devices can be manufactured in one operation, it is advantageous in terms of cost. Moreover, it can also be set as the detection apparatus which has arrange | positioned the detection body in the matrix form. Furthermore, the present invention has a structure in which the detection body can be easily thinned, and can contribute to a reduction in the thickness of the detection apparatus.

Line detecting apparatus of the present invention includes a detector cured by kneading scintillator powder and the transparent resin
It is characterized by having a photodetector for converting light into electricity, continuously changing the filling degree of the scintillator powder in the thickness direction of the detection body, and arranging the photodetector on the surface side where the filling degree is large. The amount of scintillator powder containing heavy metal is small without greatly reducing the emission intensity of the detector.
A detection body and a detection device using the detection body can be provided.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Example 1 shows a detailed manufacturing method of the detection body and a relationship between the filling degree ratio A / B and the light intensity received by the CCD sensor. Example 2 shows the relationship between the scintillator material and the average particle size of the powder and the variation in the received light intensity of the CCD sensor. Example 3 shows the relationship between the light transmittance of the translucent resin and the light intensity received by the CCD sensor. Example 4 shows the relationship between the average filling degree in the thickness direction of the detection body and the light intensity received by the CCD sensor. Example 5 shows an example of an X-ray detection apparatus in which a light reflecting material and a light detector are fixed to a detection body with a translucent resin. Example 6 shows an example of an X-ray detection apparatus in which a mixed material obtained by kneading scintillator powder and a translucent resin is applied and cured on a photodetector.

As an example of the present invention, an example is shown in which detectors with different filling degree ratios A / B are produced. A schematic diagram of the detection apparatus of the present invention is shown in FIG. The detector 1 is composed of the scintillator powder 3 and the translucent resin 4 and is characterized in that the filling degree A on the photodetector 2 side is larger than the filling degree B on the opposite surface side.

In this example, GOS was used as the scintillator powder, and the GOS powder was produced by the following procedure. G
Raw material powder of d ₂ O ₃ and S, Pr ₆ O ₁₁ and Na ₄ P ₂ O ₇ and NaC which are flux components
A predetermined amount of O ₃ was weighed and mixed. This mixture was filled in a crucible and fired in an atmospheric furnace at 1300 to 1400 ° C. for 7 to 9 hours to produce a GOS coarse powder. The flux and impurities contained in the GOS coarse powder were removed using hydrochloric acid and warm water. The coarse GOS powder was further finely pulverized using a ball mill and then made into a GOS powder having a sharp particle size distribution by a classifier. The average particle size of the GOS powder was about 50 μm as measured by a laser particle size distribution analyzer. The GOS powder was kneaded with a translucent epoxy resin dissolved in a solvent to form a paste-like mixture.

A procedure for producing the detector 1 is shown in FIG. GOS powder 5 having an average particle size of 30 μm shown in FIG.
2 g of paste-like mixture 5 consisting of 0 g and translucent epoxy resin was poured into a bowl-shaped aluminum mold 6 shown in FIG. 2 b) and cured at 80 ° C. to obtain a cured body 1 ″. The GOS powder inside was partially settled by its own weight, and the GOS powder filling degree in the depth direction was changed almost continuously. As shown in FIG. 2c), the cured body 1 ″ cured to about 1.2 mm thickness was obtained. It removed from the aluminum type | mold 6 and grind | polished to thickness 1mm, and hardened | cured body 1 'was obtained. The polished surface is a free-curing surface opposite to the surface in contact with the inner bottom of the aluminum mold 6. A cured body 1 ′ polished to a thickness of 1 mm,
As shown in FIG. 2 d), the detection body 1 was cut into a fine shape of 10 mm × 10 mm.

The ratio A / B between the filling degree A and filling degree B of the detection body 1 can be changed according to requirements such as the ratio of the amount of scintillator powder to the amount of translucent epoxy resin, and the curing temperature condition of the resin. FIG. 3 shows a change in the filling degree of the detection body 1 manufactured by changing these requirements. Since the purpose is to explain that the degree of filling can be changed almost continuously, a detailed description of the changed requirements is omitted. FIG.
The degree of filling is determined by observing a cross section perpendicular to the thickness direction of the detector and filling degree B on the side opposite to the photodetector.
Is expressed as a relative value of 1. As shown in FIG. 3, in the detector 1 of this embodiment, the filling degree of the scintillator powder changes substantially continuously in the thickness direction, and the filling degree A on the photodetector side is the filling degree B on the opposite side.
It is a larger detector.

FIG. 4 shows the relationship between the filling degree ratio A / B, the light intensity received by the CCD sensor, and the amount of powder used. By changing the ratio of the GOS powder and resin before curing, the curing temperature, and the amount of surface polishing, the filling degree A on the photodetector side is made constant at about 35%, and the detector 1 having a different filling degree ratio A / B is obtained. Produced. A / B =
The detection body No. 1 was produced by producing a hardened body 1 ″ having a thickness of about 2.1 mm, which is almost twice as large as a normal one, and mainly using the portion on the filling degree A side. It calculated from the area ratio of the scintillator powder on the surface, and the filling degree ratio A / B was calculated by dividing the filling degree A by the filling degree B.

The emission intensity of the detection body was evaluated by a measurement system including an area imaging sensor and an X-ray irradiation apparatus. The area imaging sensor is a CCD sensor having a pixel size of 0.2 mm × 0.2 mm arranged in a planar matrix, and can measure the emission intensity for each pixel. In this example,
The surface of the detection body with a filling degree A and the area imaging sensor face are arranged to face each other, and the filling degree B
X-rays were irradiated from the surface side of the light and the emission intensity of the detection body was evaluated. The light emission intensity of the detection body is represented by the average received light intensity of each CCD sensor facing the detection body. In this example, 10 samples were measured for each condition, and the average of the measured values was taken.

The amount A of scintillator powder used in the detection object is the specific gravity b of the detection object measured by the underwater substitution method.
It was calculated from the weight c of the detection body, the density d of the scintillator powder, and the density e of the epoxy resin. The amount of scintillator powder used was determined by A = (b−e) × c / (d−e).

FIG. 4 shows the received light intensity of the CCD sensor and the amount of scintillator powder used as a filling ratio A /
A relative value with the value of the detection object of B = 1 being 100 is shown. When the filling degree ratio A / B of the detection body is 5.0 or less, the received light intensity of the CCD sensor, which is the emission intensity of the detection body, is 93% or more. But,
When the filling degree ratio A / B exceeds 5.0 and reaches 5.6, the received light intensity of the CCD sensor is about 80%.
It will drop rapidly. Further, the amount of scintillator powder used for the detection object is the filling ratio A /
When B is 1.1 or more, it can be decreased linearly. By setting the ratio A / B of the filling degree A and the filling degree B to 1.1 or more and 5.0 or less, a detection body with a small amount of scintillator powder used could be produced without greatly reducing the emission intensity.

As another embodiment of the present invention, FIGS. 5 and 6 show the average particle size and C of the scintillator material and powder.
The relationship with CD sensor light reception intensity variation is shown. The scintillator material used in this example is GO.
S, GGAO, CWO, CI, BGO. Sintered and single crystal scintillator bulk materials and residual materials are finely pulverized with a ball mill and classified to have an average particle size of 6.1 μm to 122 μm.
Scintillator powder was obtained. Although an attempt was made to reduce the average particle size of the scintillator powder to less than 5 μm, the yield was poor and a detector could not be produced. The obtained scintillator powder was mixed with a translucent epoxy resin dissolved in a solvent, and a detector was prepared in the same manner as in Example 1.
The filling degree ratio A / B of the detection body is set in the range of 2.5 to 3.5, and the detection body is 10 mm.
It processed into the dimension of * 10mm * 1mm.

As in Example 1, the emission intensity of the detector was evaluated by a measurement system including an X-ray area imaging sensor and an X-ray irradiation apparatus. Arrange the surface of the detection body A so that the surface of the area imaging sensor faces, and irradiate the X-ray from the surface of the surface of the filling B to determine the emission intensity of the detection body.
It was measured by the received light intensity of the sensor. In order to obtain the optimum value of the average particle size of the scintillator powder, the evaluation was performed based on variations in received light intensity rather than absolute values of received light intensity. The variation in received light intensity was obtained as a percentage by dividing the difference between the maximum received light intensity value and the minimum received light intensity value by the average received light intensity value from the received light intensity value of the CCD sensor facing the detector.

5 and 6 show the evaluation results. FIG. 5 shows the relationship between the scintillator material, the average particle diameter, the filling degree ratio A / B of the detection body, and the variation in received light intensity (%) of the CCD sensor. Figure 6 shows CC
It shows the relationship between the variation in received light intensity of the D sensor and the average particle size of the scintillator powder.
From FIG. 5 and FIG. 6, when the average particle size of the scintillator powder is in the range of 6.1 μm to 100 μm, the variation in received light intensity of the CCD sensor is about 5% or less, and the emission intensity of the detection body is stable. In other words, it can be said that the detection body is a high-quality detection body having no emission intensity unevenness. When the average particle size of the scintillator powder exceeds 100 μm, the variation in received light intensity of the CCD sensor increases rapidly. When the average particle diameter exceeds 100 μm, the variation in the received light intensity exceeds 10%, and it has been confirmed that it is difficult to use as a detector due to uneven emission intensity.

As another embodiment of the present invention, FIG. 7 shows the relationship between the light transmittance of the translucent resin and the light intensity received by the CCD sensor. In this example, GOS scintillator powder was used. The end material and the remaining material of the GOS material were pulverized with a ball mill and classified to obtain a scintillator powder having an average particle size of 55 μm. The scintillator powder was mixed with a translucent resin dissolved in a solvent, and a detector was prepared in the same manner as in Example 1. In this example, a light-transmitting resin having a light transmittance of about 75% to about 95% was used.
The detector has a filling degree ratio of 2.8 to 3.2 and an average filling degree of about 55%. The detection body was processed into a size of 10 mm × 10 mm × 1 mm.

Similarly to Example 1, the emission intensity of the detector was evaluated by a measurement system including an area imaging sensor and an X-ray irradiation device. In the present example, the surface of the detection body having a filling degree A and the area imaging sensor surface are arranged to face each other, and X-rays are irradiated from the surface side of the filling degree B to evaluate the emission intensity of the detection body. The light emission intensity of the detection body was used by averaging the light reception intensity values of the CCD sensors facing the detection body. The luminous intensity of the detector is expressed as a relative value to the luminous intensity of the sintered detector, which is a bulk material of the same size, and the received light intensity of the detector of this example is divided by the received light intensity of the bulk material detector and displayed as a percentage. It was.

From FIG. 7, the light intensity of the CCD sensor could be 65% or more by setting the light transmittance of the translucent resin to 85% or more. It was found that when the light transmittance of the translucent resin is 80%, the light receiving intensity of the CCD sensor is greatly reduced to about 50%. The degree of decrease is large, and the light intensity of the CCD sensor is about 50%, which is 1 by simply decreasing the light transmittance of the translucent resin by 5 points from 85%.
It can be seen that it will drop by 5 points. In FIG. 7, an epoxy resin and a polyester resin are used as the translucent resin, but similar results were obtained even when acrylic, silicon rubber, vinyl, or the like was used.

As another embodiment of the present invention, FIG. 8 shows the relationship between the average filling degree in the thickness direction of the X-ray detector and the light intensity received by the CCD sensor. In this example, the same GOS scintillator powder as in Example 3 was used, and a detector was prepared in the same manner as in Example 1. An epoxy resin and a polyester resin having a light transmittance of about 93% are used as the translucent resin, the filling degree ratio is 2.8 or more and 3.2 or less, and the average filling degree is changed from 30% to 55%. It was. The detection body is 10mm x 10mm x 1m
Processed to dimensions of m. The emission intensity of the detection body was evaluated by a measurement system including an area imaging sensor and an X-ray irradiation apparatus. Comparison of the evaluation method and data was performed in the same manner as in Example 3.

From FIG. 8, when the average filling degree of GOS powder is 35% or more, the light receiving intensity of the CCD sensor is 60.
It was found that a high emission intensity of at least% was obtained. It has been found that when the average filling degree of GOS powder is less than 35%, the light receiving intensity of the CCD sensor rapidly decreases. The degree of decrease is large, and the average filling degree is only 5 points down from 35%, and the received light intensity of the CCD sensor is about 51%, which is 1
It turns out that it will drop nearly 0 points. In FIG. 8, an epoxy resin and a polyester resin are used as the translucent resin, but similar results were obtained even when acrylic, silicon rubber, vinyl, or the like was used. A sample having an average filling degree of GOS powder exceeding 60% was produced. However, the detection body became brittle, and corners were lost during measurement preparation, so that stable measurement could not be performed.

As another embodiment of the present invention, a detection device 9 in which a light reflecting material 7 and a light detector 2 are fixed to a detection body in which scintillator powder and a light transmission resin are mixed in FIG. The model of is shown.
For the detector of this example, the same GOS scintillator powder as in Example 3 was prepared in the same manner as in Example 1. As the translucent resin, an epoxy resin having a light transmittance of about 93% was used, and the filling degree ratio was set to 3.1. The dimensions of the detection body were 11 mm × 11 mm × 1 mm. A photodiode was used for the photodetector 2.

The light reflecting material 7 includes TiO ₂ having a light reflectance of 80% or more, and the fixing translucent resin 8 includes a wavelength 4
An epoxy resin having a light transmittance of 85% or more in the range of 50 to 650 nm was used, and a detection device was produced in each combination. The produced detector was irradiated with X-rays, and the output current of the photodiode was measured. A comparative detection device using a GOS bulk material was produced and compared with the present example. The greater the light reflectance of the light reflecting material 7 and the greater the light transmittance of the fixing translucent resin 8, the greater the output current of the photodiode. The output of the comparative detection device using the GOS bulk material, in which the light reflectance of the light reflecting material 7 is 90% or more, and the light transmittance of the fixing translucent resin 8 in the wavelength range of 450 to 650 nm is 95% or more. A value of 70% or more was obtained.

As another embodiment of the present invention, FIG. 10 shows an example of a detection device in which a mixed material obtained by kneading scintillator powder and translucent resin is applied and cured on a photodetector. In this example, the fixing translucent resin 8 for bonding the detector 1 and the photodetector 2 of Example 5 can be omitted. FIG. 10 shows the detection apparatus of this embodiment. The detection device 9 is provided with the photodetector 2 and the detection body 1 in a hole formed in the support body 10.
On the surfaces of the detection body 1 and the support body 10 processed in the same plane, a light reflecting material 7 is interposed via a translucent resin 8.
Is provided. The received light current that is the output of the photodetector 2 is output to the outside through a through hole provided in the support 10. The detector 1 was made of the same GOS scintillator powder as in Example 3, and the translucent resin was an epoxy resin having a light transmittance of about 93%.

A procedure for manufacturing the detection device used in this example will be described with reference to FIGS. The support 10 shown in FIG. 11 a) is a glass epoxy plate having a thickness of 6 mm, and holes of 11 mm × 11 mm × depth 3 mm are formed with an interval of 2 mm. A photodiode was fixed to the hole of the support 10 with a resin as the photodetector 2. As shown in FIG. 2b), a mixture 5 made of GOS powder and a translucent resin is applied so as to fill the hole. Curing was performed while controlling the temperature and time, and the filling degree of the GOS powder was changed almost continuously from the surface of the photodetector 2. As shown in FIG. 11 c), the surface of the detection body 1 was polished to be flush with the surface of the support 10. As shown in FIG. 11 d), a fixing translucent resin 8 made of an epoxy resin is formed on the surfaces of the support 10 and the detection body 1 by 20 μm.
Thickly applied. A light reflecting material 7 made of rutile type TiO ₂ and having a thickness of 200 μm is bonded to FIG.
The detection device shown in e) was obtained.

The detection body and X-ray detection apparatus of the present invention can be used in medical applications for inspecting the inside of a living body, business applications such as baggage inspection, and industrial applications such as a foreign matter contamination inspection apparatus.

It is a schematic diagram of the X-ray detection apparatus of Example 1 of this invention. It is a figure which shows the preparation procedures of the detection body of Example 1 of this invention. It is a figure which shows the filling degree ratio A / B of the thickness direction of the detection body of Example 1 of this invention. It is a figure which shows the relationship between the filling degree ratio A / B of the detection body of Example 2 of this invention, CCD sensor light reception intensity | strength, and powder usage-amount. It is a figure which shows the relationship of the scintillator material of Example 2 of this invention, average particle diameter, filling degree ratio A / B, and light reception intensity dispersion | variation. It is a figure which shows the relationship between the CCD sensor light reception intensity variation of Example 2 of this invention, and the average particle diameter of a scintillator powder. It is a figure which shows the relationship between the CCD sensor light reception intensity | strength of Example 3 of this invention, and the light transmittance of translucent resin. It is a figure which shows the relationship between CCD sensor light reception intensity | strength and scintillator powder average filling degree of Example 4 of this invention. It is a schematic diagram of the X-ray detection apparatus of Example 5 of this invention. It is a schematic diagram of the X-ray detection apparatus of Example 6 of this invention. It is a figure which shows the preparation procedures of the X-ray detection apparatus of Example 6 of this invention. more than

Explanation of symbols

1 detector, 1 'polished cured body, 1 "cured body, 2 photodetector,
3 scintillator powder, 4 translucent resin, 5 mixture, 6 aluminum mold,
7 light reflecting material, 8 translucent resin for fixing, 9 X-ray detector, 10 support.

Claims (4)

X-ray detector obtained by kneading and curing scintillator powder and translucent resin, and converting light into electricity
An X-ray detection apparatus having a photodetector as a constituent element, the filling degree of the scintillator powder changes substantially continuously in the X-ray detector thickness direction, and the filling degree A on the photodetector side is filled on the opposite side. Greater than degree B, and the ratio A / B between the degree of filling A and the degree of filling B is 1.1 or more and 5.0 or less X
Line detector . The scintillator powder is Gd ₂ O ₂ S, Gd ₃ Ga ₂ Al ₃ O ₁₂ , CdWO ₄ ,
The X-ray detection apparatus according to claim 1, wherein the compound is selected from CsI and Bi ₄ Ge ₃ O ₁₂ and has an average particle diameter of 10 to 100 μm. In the range of the light-transmitting resin wavelength 450 to 650 nm, X-ray detector according to claim 1, JP <br/> symptoms that a light transmittance of 85% or more. X-ray detecting device according to claim 1, wherein the average degree of filling of the scintillator powder X-ray detector the thickness direction is equal to or less than 60% than 35%.

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