JPS6352717B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a fine honeycomb structure of a collimator used, for example, with a scintillation camera, and in particular to a method for manufacturing a honeycomb structure with a focal point.

A collimator for a scintillation camera is used to pass only radiation emitted from spatially distributed radioactive isotopes in a desired direction.In general, collimators for scintillation cameras pass through radiation emitted from spatially distributed radioactive isotopes. A block of high-numbered material, particularly lead or lead alloy, is used from the viewpoint of ease of processing and economy, and is formed by providing fine straight holes in the block. It is extremely difficult to create fine holes uniformly and densely by machining, so they are formed by metallurgically joining corrugated lead or lead alloy plates of appropriate shapes, or Wire rods with a thin alloy plate as the outer sheath and a core material made of a material that is more easily soluble in certain chemicals, etc. are cut into appropriate lengths, tied and aligned, and adjacent wire rods are appropriately joined. It is becoming common practice to remove only the core material by appropriately dissolving it.

In any case, the pores of the honeycomb structure formed in this way are generally parallel and do not have focal points. On the other hand, a collimator consisting of a so-called converging or diverging honeycomb structure having a closest focal point or focal line can partially enlarge the image.
It is desired for the formation of reduced images and/or tomographic images.

A method of manufacturing a honeycomb structure having such a focal point is disclosed in, for example, Japanese Patent Application Laid-Open No. 133872/1983.
In the manufacturing method disclosed by JP-A-Sho, a block of a honeycomb structure having parallel holes formed as described above before the core material is melted and removed is placed in an appropriate mold jig and subjected to appropriate processing. It is pressed to plastically deform it, and after cutting, the core material is melted to form a honeycomb structure with a focal point. Since this method utilizes plastic deformation of the block, there is a high possibility that uncontrollable distortion will be introduced, and therefore the reliability of the performance of the obtained collimator is low.

Other conventional methods for constructing focused honeycomb structures are disclosed in Japanese Patent Application Laid-open No. 55-7672 and No. 55-97949. The method shown in JP-A-55-7672 uses a batten with alignment holes and guide pins passing through the alignment holes to fix the above-mentioned wire at one end to a tapered jig with an open upper part. After oriented in the jig so as to converge, the direction is fixed with epoxy resin to form a block, and the core material is then melted. Although this method is effective, the process of orienting the wire with guide pins is relatively difficult. Also, JP-A-55-97949
According to the technique shown in , after the open end side of a wire bundle placed in a taper jig is brought into contact with one side of a membrane material made of an elastic material such as rubber in the same manner as above, this membrane is Pressure is applied from the other side of the material to expand and deform the membrane material, thereby widening and fixing the open end side, and cutting to create a flat surface after removing the core material, but this method causes uncontrollable distortion. There is a high possibility that this will occur, which poses a practical problem.

It is an object of the present invention to provide a method for manufacturing a honeycomb structure for a collimator with a distortion-free focal point or focal line using relatively simple steps.

Hereinafter, one embodiment of the method of the present invention will be described based on the accompanying drawings.

As a result, from the viewpoint of uniformity of sensitivity and linearity of the collimator, it is desirable that the cylinder be made of lead, have a sufficiently small lead wall thickness, and have a hole and outer shape with a regular hexagonal cross section. Therefore, in this embodiment as well, a composite wire having a regular hexagonal cross section and having an outer sheath made of lead or a lead alloy and a core made of aluminum as disclosed in the above-mentioned Japanese Patent Application Laid-open No. 133872/1982 is used as the cylindrical body. Note that aluminum will be dissolved and removed later.

FIG. 1 is a sectional view illustrating a first stage and a second stage in an embodiment of the present invention. That is, the first
In this step, as shown in FIG. 1, a large number of cylinders 4 each made of the composite wire cut into uniform lengths are brought into close contact with each other with their end surfaces aligned without any gaps as shown in FIG. A directional assembly is formed along the axis of the body 4.

Next, in the second step, a tapered mold (tapered jig) 5 is used to position and fix one end surface onto the base material 6, while leaving the other end surface free. This work is completed by pushing the base material 6 into the tapered mold 5 as shown in FIG. 2 after FIG. 1.

Next, FIGS. 2, 4, and 5 illustrate the third stage in an embodiment of the present invention. In the third step, in FIG. 2, the cylindrical body 4 on the free end side of the aggregate in the taper mold 5 is traversed from three directions along the sides of the hexagon (respectively, A linear spacer 10 is inserted into every other cylindrical body 4 that has been brought into close contact with each other, and first, as shown in FIG. The free end side of the assembly is expanded in one direction by separating the parts in the direction shown in FIG. Next, as shown in FIG. 5, spacers 20 and 30 are inserted along the hexagonal sides of the cylinder 4 to expand it in two directions. As a result, the free end side of the aggregate as a whole becomes XYZ (see Figure 3) as shown in Figure 5.
Expands in three directions. Of course, the degree of expansion or spacing can be equally spaced based on the dimensions of the spacer 10.

The fourth step will be explained with reference to FIG. 2, in which the assembly whose free end side is expanded in three directions as described above is positioned in the tapered mold 5,
A suitable adhesive (filling and fixing material) such as epoxy resin is injected into the gap and solidified to join the cylinders 4 together.

As for the fifth step, similarly referring to FIG. 2, the block-shaped aggregate is taken out from the taper mold 5, and its both end faces are marked along the line a,
Cut parallel to each other along b. As a result,
The fixed end side of the stack is as shown in FIG. 3, while the free end side is expanded in three directions and becomes as shown in FIG. 5 described above.

Thereafter, the aggregate is immersed in an alkaline solution, for example, an aqueous caustic soda solution, to dissolve and remove the aluminum provided as the core material of the cylinder 4. As a result, a desired focused honeycomb structure is obtained.

In this embodiment, an example in which a composite wire is used as the cylindrical body has been described, but the present invention is not limited to this, and it goes without saying that a hollow cylindrical body may be used from the beginning.

As is clear from the above description, according to the present invention, a cylindrical body having a hole and an external shape with a regular hexagonal cross section is used, and a large number of cylindrical bodies are closely brought together without any gaps to form an aggregate. Using a tool, one of the cylindrical bodies on the free end side of the stack located in the taper jig is traversed from three directions along the sides of the hexagon, and one of the cylindrical bodies closely spaced. By inserting linear spacers in alternate directions and separating the closely-closed cylindrical bodies in a direction orthogonal to the direction in which the spacers are inserted, the free end side of the aggregate is expanded in three directions. By utilizing the regular hexagonal shape of the cylindrical body constituting the body, the expansion of the aggregate in the three directions can be performed extremely accurately, and as a result, a honeycomb structure with an extremely excellent structure in terms of dimensions and structure can be obtained. Therefore, when this is used as a collimator for a scintillation camera, it has the effect that image shift, distortion, etc. will not occur in the camera.

Further, according to the present invention, a linear spacer is used and the linear spacer is inserted into the cylindrical body on the free end side (of the aggregate) in a direction transverse to each other from three directions along the sides of the hexagon. Since the aggregate is expanded in three directions, such a spacer itself can be prepared very easily (it is easy to work with).
In addition, by utilizing the shape of the cylinder (hexagonal), which has a superior structure compared to conventional technology in which a spacer or guide pin is inserted along the axis of the cylinder, expansion can be performed extremely easily and with high precision. It has the effect of being able to

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the first step in an embodiment of the present invention, FIG. 2 is a diagram showing an example of the steps after FIG. 1, and FIG. 3 is a diagram showing the aligned materials in FIG. 1. Fig. 4 is a diagram showing the positional relationship when the material in Fig. 2 is expanded in one direction, Fig. 5 is a diagram showing the positional relationship when the material is expanded in the other direction, and Fig. 6 is a partial top view of the completed honeycomb structure. It is. 4... Cylindrical body, 5... Taper mold, 6... Base material, 1
0, 20, 30...Spacer.

Claims (1)

[Claims] 1 A cylinder is formed by aligning a large number of cylinders (composite wire) having a hole and external shape with a regular hexagonal cross section, or having a core material in the hole that is later melted and removed (composite wire), with their end surfaces aligned and closely spaced without any gaps. a process of forming an aggregate having directionality along the axis of the body; a process of positioning the aggregate in the tapered jig with one end face fixed and the other end free; a taper jig; Insert a linear spacer in a direction transverse to the cylinder on the free end side of the aggregate in the tool from three directions along the sides of the hexagon, and in every other cylinder that is brought into close contact with each other. a step of expanding the free end side of the aggregate in three directions by separating the closely-closed cylindrical bodies in a direction perpendicular to the insertion direction of the spacer, and injecting a filling and fixing material during the separation interval. 1. A method for manufacturing a focused honeycomb structure, comprising the steps of: solidifying the honeycomb structure; and removing the aggregate formed into blocks from the taper jig and cutting a portion of both end faces parallel to each other.