JPH04145667A - Manufacture of radiation detector - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a method of manufacturing a radiation detector in which a photodiode and a scintillator are integrated.

(Prior art) For example, in an X-ray CT apparatus, as shown in FIG. While irradiating X-rays, it rotates together with the detector 2 in the direction of the arrow, and reconstructs the X-ray projection data detected by the detector 2, thereby creating an arbitrary slice of the subject 3. It is configured to take a tomographic image along a plane.

Here, the detector 2 that detects the X-ray projection data of the subject 3 is generally of a structure in which a scintillator that converts X-rays into light and a photodiode that converts this light into an electrical signal are integrated. It has been adopted. In detail, for example, 16 CH or 2 channels for multiple channels (CH) on a common board.
A detector block is formed by integrating scintillators and photodiodes for 4 CHs, and a plurality of these detector blocks are arranged adjacently to constitute a detector for a desired CH. - For example, if 32 detector blocks for 16 channels are arranged, a detector for 512 channels will be obtained.

FIG. 3 shows a conventional manufacturing method of such a detector block (hereinafter simply referred to as a detector). First, a scintillator substrate 4 is prepared, and with this scintillator substrate 4 supported by a support plate 5, a wire saw is used. 6, the scintillator elements 4a, 4b4c, . . . are cut into strips with a width W corresponding to each CH. Next, each scintillator element 4a, 4b, 4c, --- is connected with a spacer (
A scintillator block is formed by alternately arranging the scintillator blocks with the adhesive 8 through the light reflecting plate 9, and then a plurality of sensitive parts 7a, 7b, 7c prepared in advance as shown in FIG.
.

The scintillator block is fixed onto the photodiode substrate 7 with the adhesive 10 formed thereon to integrate the scintillator block. In this case, in the scintillator block, the scintillator elements 4a, 4b, 4c, . . . are each sensitive portion 7a on the photodiode substrate 7.

7b, 7c, . . . must be positioned and fixed so as to correspond to the above.

(Problem to be Solved by the Invention) However, in the conventional manufacturing method, when each scintillator element is bonded alternately through a spacer, non-uniformity occurs in the film thickness of the adhesive, and each scintillator element and photodiode are bonded to each other. Since the pitch deviation occurs in the arrangement direction of the sensitive parts, there is a problem in that some light leaks to the neighboring sensitive parts and crosstalk occurs between each CH. For example, in part A of FIG. 4, the scintillator element 4a is misaligned with the corresponding sensitive section 7a, so that light leaks to the adjacent sensitive section 7b. For this reason, when an image is reconstructed based on the X-ray projection data detected by the detector, artifacts occur in the image, resulting in a decrease in image quality.

The present invention has been made in response to the above-mentioned problems.
It is an object of the present invention to provide a method for manufacturing a radiation detector in which pitch deviation does not occur in the arrangement direction of each scintillator element and each sensitive part of a photodiode.

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above object, the present invention provides a step of preparing a photodiode substrate on which a plurality of mutually insulated sensitive parts are formed; a step of bonding a scintillator substrate thereon; a step of forming a plurality of grooves reaching the photodiode substrate in an area other than the sensitive part of the scintillator substrate; and a step of inserting a spacer into each of the plurality of grooves. It is characterized by:

(Function) After a scintillator substrate is bonded onto a photodiode substrate on which a plurality of sensitive parts are formed, a plurality of grooves reaching the photodiode substrate are formed in a region of the scintillator substrate other than above the sensitive parts, and these grooves are formed. Insert spacers into each of the plurality of grooves. According to Kono's manufacturing method, after bonding the scintillator substrate onto the photodiode substrate, insulating grooves are formed for each scintillator element, avoiding the sensitive parts, and spacers are inserted into these grooves. No pitch deviation occurs in the arrangement direction of the sensitive parts of the scintillator element and the photodiode. Therefore, since it is possible to prevent Talostalk between each CH, no artifacts occur in the image.

(Example) The present invention will be described in detail below with reference to the drawings.

FIG. 1 is a cross-sectional view showing an embodiment of the method for manufacturing a radiation detector according to the present invention, first showing a plurality of sensitive parts 7a.

A photodiode substrate 7 in which 7b, 7c, . . . are formed insulated from each other is prepared. Sensitive part 7a.

7b, 7c,... are the number of channels you need, for example 16
CH or 24 CH is formed. Next, a scintillator substrate 4, for example, CaWO, (tungsten calcium oxide), NaI' (sodium iodide), ZnWo4, which has been formed in advance to have a width of 16 CH or 24 CH, is used.
(tungsten zinc oxide) or the like is prepared and adhered to the photodiode substrate 7 using a transparent adhesive 11 such as silicone resin. Let the film thickness of the adhesive 11 be t.

Next, as shown in FIG.
7b, 7c, . . . Grooves 13 that cut the area of the scintillator substrate 4 other than directly above and reach the photodiode substrate 7
Form multiple. That is, the scintillator substrate 4 and adhesive 1 in the area directly above the dead section 14 of the photodiode substrate 7
1 is cut to form a groove 13. Since the scintillator substrate 4 and adhesive 11 are transparent, this cutting operation is performed by observing the sensitive parts 7a, 7b, and 7c from above.

... and the blind portion 14 can be distinguished, so that only the target area can be easily cut.

Note that the width Wt of the diamond blade 12 is smaller than the width wh of the dead section 14. If lol
When t>wh, the sensitive parts 7a and 7b.

The light-receiving area of 7c, . . . becomes smaller, causing deterioration of photoelectric conversion characteristics.

Next, a spacer 9 is inserted into each groove 13.

The spacer 9 is made of a metal plate made of lead or the like which has a high X-ray absorption rate, and both sides are coated with white paint such as TiO2 (titanium oxide) in order to efficiently reflect light.
Each scintillator element 4a, 4b, 4c is attached by adhesive 8.
, ... are glued between them.

According to this embodiment, after a scintillator substrate is bonded onto a photodiode substrate on which a plurality of sensitive parts are formed, the area of the scintillator substrate other than directly above the sensitive parts is cut into the photodiode substrate. Since a plurality of grooves reaching each other are formed and a spacer is inserted into each of these grooves, a pitch deviation does not occur in the arrangement direction of each scintillator element and each sensitive part of a photodiode as in the conventional case.

That is, scintillator elements 4a, 4b, 4c.

...As shown in Figure 2, it will not fall off.
The corresponding sensitive parts 7a, 7b, 7c, . . . are arranged directly above them. Therefore, no crosstalk occurs between the CHs, so when an image is reconstructed based on the X-ray projection data detected by the detector, no artifacts occur in the image, so the image quality does not deteriorate.

The accuracy of the machining process to form the groove 13 is determined only by the feed pitch accuracy of the machining process, so the pitch accuracy in the arrangement direction of each scintillator element and each sensitive part of the photodiode can be high, resulting in high performance. Detectors can be easily manufactured.

Note that the number of CHs to be formed can be arbitrarily selected, and the materials of the photodiode and scintillator can also be arbitrarily selected.

[Effects of the Invention] As described above, according to the present invention, a scintillator substrate is bonded onto a photodiode substrate and then cut into each scintillator element to provide a spacer. Since no pitch deviation occurs in the arrangement direction of each sensitive section, it is possible to prevent crosstalk between each CH.

[Brief explanation of drawings]

1 and 2 are cross-sectional views showing the method of manufacturing the radiation detector of the present invention, FIGS. 3 and 4 are perspective views and cross-sectional views showing the conventional manufacturing method, and FIG. 5 is an X-ray CT apparatus. FIG. 2 is a schematic diagram showing the configuration of. 2...Detector, 4...Scintillator board, 4a, 4
b, 4cm scintillator element, 7... diode substrate, 7a, 7b, 7c,... sensitive part, 8... adhesive, 9
...Spacer, 11...Transparent adhesive, 13...
Groove, 14... dead section.

Claims (1)

[Claims] A step of preparing a photodiode substrate on which a plurality of mutually insulated sensitive parts are formed, a step of adhering a scintillator substrate on the photodiode substrate, and a step of bonding the scintillator substrate to an area other than directly above the sensitive parts of the scintillator substrate. 1. A method of manufacturing a radiation detector, comprising the steps of: forming a plurality of grooves reaching the same length; and inserting a spacer into each of the plurality of grooves.