JPS6352716B2 - - Google Patents

Description

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

A collimator for a scintillation camera is used to pass only radiation emitted from spatially distributed radioactive isotopes in a desired direction, and is generally made of a collimator that is opaque to the radiation and has a specific gravity. It is formed by using a block of material with a high atomic number, especially lead or lead alloy from the viewpoint of ease of processing and economy, and by providing fine straight holes in it. 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 or unidirectional focal point, that is, a focal line, is shown in, for example, Japanese Patent Laid-Open No. 133872/1983. In the manufacturing method disclosed by JP-A-Sho, the block of the 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 the block is appropriately pressurized. The core material is then plastically deformed, 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 manufacturing focused honeycomb structures are disclosed in Japanese Patent Application Laid-open No. 55-7672 and No. 55-97949. The method shown in Japanese Patent Application Laid-open No. 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 then the core material is 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.
Furthermore, in a honeycomb structure with a unidirectional focus, it is extremely important for scanning when used in a scintillation camera that the honeycomb array has linearity in a direction in which there is no focus.

An object of the present invention is to provide a method for manufacturing a honeycomb structure for a collimator having a focal line, which has excellent linearity in non-focal directions and is free from distortion, by using a relatively simple process. It is.

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. Accordingly, 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. 52-133872 is used as the cylinder. 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
As a step, as shown in FIG. 1, a large number of cylinders 4 made of the above-mentioned composite wires are aligned with their end faces and brought into close contact with each other without any gaps as shown in FIG. form an aggregate with

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 and 4 illustrate the third stage in one embodiment of the present invention. In the third step, in FIG. 2, the cylindrical body 4 is brought into close contact with the aggregate in the taper mold 5 in a direction transverse to the cylindrical body 4 on the free end side (direction perpendicular to the plane of the paper). Insert linear spacers 10 into every other space,
As shown in FIG. 4, the free end side of the stack is expanded in one direction by separating the closely-closed cylinders 4 in a direction perpendicular to the insertion direction of the spacer 10. 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 one direction 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 of the stack is as shown in FIG. 3, while the free end is expanded as shown in FIG.

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 unidirectionally 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 integrated body, while the taper treatment using a tool, inserting a linear spacer in a direction transverse to the cylindrical body on the free end side of the stack located in the tapered jig and into every other closely-closed cylindrical body, Since the free end side of the aggregate is expanded in one direction by separating the closely-closed cylindrical bodies in a direction perpendicular to the insertion direction of the spacer, a direction perpendicular to the expansion direction, that is, a direction that does not have a focal point. Since the sides of the regular hexagonal cylinder remain close together, the linearity of the cylinder in the direction that does not have its focal point is ensured, and as a result, the honeycomb structure obtained by this manufacturing method When used as a collimator for a scintillation camera, it has the effect that image shift, distortion, etc. do not occur in the camera.

Further, according to the present invention, since the linear spacer is inserted in a direction transverse to the cylindrical body on the free end side of the aggregate to expand the aggregate, the spacer itself is extremely In addition to being easy to prepare, it is also extremely easy to use by utilizing the shape of the cylinder (hexagonal), which has a superior structure compared to conventional techniques in which a spacer or guide pin is inserted along the axial direction of the cylinder. It has the effect that expansion can be performed with high precision, and as a result, a focused honeycomb structure having an excellent structure in terms of size and structure can be obtained.

[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 due to unidirectional expansion of the material in FIG. 2, and FIG. 5 is a partial top view of the completed honeycomb structure. 4... Cylindrical body, 5... Taper mold, 6... Base material, 10
…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; A linear spacer is inserted in a direction transverse to the cylinders on the free end side of the aggregate in the tool, and into every other cylinder that is brought into close contact with each other, and the cylinders that are brought into close contact with each other are inserted into the spacer. a step of widening the free end side of the aggregate in one direction by separating them in a direction perpendicular to the above-mentioned direction, a step of injecting and solidifying a filling fixing material during the spacing, and an aggregate formed into blocks by the above step. 1. A method for producing a honeycomb structure with a unidirectional focus, comprising the steps of taking out the body from a taper jig and cutting part of both end faces thereof in parallel.