Beam window

Abstract

To provide a beam window to be installed on a vacuum vessel or pressure vessel, which is inexpensive, reduces beam loss, and can withstand higher pressure difference.SOLUTION: A beam window to be installed on a receiving flange of a device is provided, the beam window being an integral metal object consisting of a spherical shell portion with a beam path, and a flange portion connected to an end of the spherical shell portion and attached to the receiving flange, where the integral metal object is an integrally stacked object of a metal.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a beam window that is attached to a vacuum vessel or pressure vessel, and more particularly to a beam window that is inexpensive, reduces beam loss, and can withstand higher pressure differences. [Background technology]

[0002] Vacuum and pressure vessels are isolated from the surrounding atmosphere, but sometimes require beam windows with thin, low-density sections, such as X-ray transparent windows in medical X-ray tubes and particle transparent windows in accelerator science, to separate the vacuum from the atmosphere or the atmosphere above atmospheric pressure from the atmosphere.

[0003] When a particle beam passes through a beam window, problems occur due to heat and radiation generated by beam loss, and the beam transport efficiency decreases. For this reason, it is desirable to minimize the product of the thickness and density of the beam window. If the number of particles lost through the beam window can be halved, this will have the same effect as increasing the intensity of the accelerator.

[0004] On the other hand, the beam window is required to withstand the pressure difference between vacuum and the atmosphere, and in some cases, a pressure difference equal to or greater than the atmospheric pressure of the ambient gas.

[0005] Therefore, it is desirable to realize a beam window made of a material that is low in density and thin, and at the same time, high in strength and large in elongation.

[0006] Conventional beam windows include: (1) Plate method using high-density SUS thin plate or thick titanium alloy plate or beryllium plate (Figure 10) (2) A method of machining from a single piece, where the thickness is determined by the workability of the material There is.

[0007] First, in the plate method, although stainless steel plates have a high density, they can be made thin, while titanium alloys (Non-Patent Document 1) are available in thicknesses of around 0.6 mm, but the thickness and shape are limited by restrictions on deformation from the plate, and the pressure difference is also limited by stress concentration.

[0008] Specifically, as shown in Fig. 10, a conventional plate beam window 11 is manufactured by joining a flat plate to a flange portion 15, and attaching it to a receiving flange 16 of a vacuum vessel via a seal member 16a. When the spherical shell portion 12 is formed, the stress generated in the spherical shell portion 12 by the pressure at the center, which is the beam passing portion 12a, is reduced as the recess 12c becomes larger.

[0009] Even if the plate thickness is reduced, if the plate stretches and the recess 12c becomes larger, the stress is reduced. On the other hand, if the recess 12c becomes larger, the edge of the plate is fixed to the flat flange portion 15 (joint portion 13) and deformation is restricted, so that the angle at the end 12b of the spherical shell portion 12 becomes steep, causing stress concentration and causing the spherical shell portion 12 to break.

[0010] Therefore, a thin beam window can be realized by enlarging recess 12c and at the same time reducing the stress at end 12b of spherical shell portion 12. When manufacturing a conventional plate beam window 11, the edge of the plate is joined to flange portion 15 (joint 13) by brazing or welding, but joining without deflection is difficult and expensive to manufacture.

[0011] That is, in the conventional plate beam window 11, the performance is limited by the original plate shape, material and workability of the window material to be joined to the flange portion 15.

[0012] On the other hand, to seal the edge of the plate and the flange, gaskets such as metal O-rings or rubber O-rings can be used depending on the type of flange, and they can be fastened together with bolts and nuts. However, metal O-rings are technically difficult to use, and rubber O-rings have problems such as outgassing, where gas is released when heated, and the temperature range in which they can be used is narrow.

[0013] On the other hand, with the cutting method, there are limitations on the material and thickness due to the processability of cutting out a one-piece structure from a bulk material, and the manufacturing costs are also high. [Prior art documents] [Patent documents]

[0014] [Patent Document 1] Japanese Patent Application Publication No. 10-82900 [Patent Document 2] JP 2001-305281 A [Non-patent literature]

[0015] [Non-Patent Document 1] Shunsuke Makimura and Taku Ishida, “Current status and trends of secondary particle generation targets and beam windows development for megawatt high intensity proton beam operation”, High Energy News, Volume 36 Number 3 October / November / December 2017 Summary of the Invention [Problem to be solved by the invention]

[0016] SUMMARY OF THE PRESENT EMBODIMENT The present invention relates to a beam window to be attached to a vacuum vessel or a pressure vessel, and more specifically, an object of the present invention is to provide a beam window which is inexpensive, reduces beam loss, and can withstand a higher pressure difference. [Means for solving the problem]

[0017] In order to solve the above problems, the present invention provides: (1) A beam window attached to a receiving flange of the apparatus, A beam window characterized in that it is an integral metal body consisting of a spherical shell portion having a beam passing portion and a flange portion connected to an end of the spherical shell portion and attached to the receiving flange. (2) The beam window according to (1), characterized in that the flange portion is provided with a notch. (3) A beam window attached to a receiving flange of the apparatus, a spherical shell portion having a beam passing portion, the spherical shell portion being connected to an end of the spherical shell portion; A beam window comprising a flange portion attached to the receiving flange by an outer flange body that circumscribes the flange portion, the spherical shell portion and the flange portion being an integral laminated metal object. (4) The beam window according to any one of (1) to (3), characterized in that the spherical shell portion connected to the flange portion is provided in two with a space therebetween, and the space serves as a flow path for a cooling medium. (5) The beam window according to any one of (1) to (4), wherein a cooling medium flows inside the flange portion. (6) The beam window according to any one of (1) to (5), wherein a connecting portion where the end of the spherical shell portion and the flange portion are connected is thicker than the beam passing portion. (7) The beam window according to any one of (1) to (7), wherein the metal integral object is an integrated metal laminated object. It was decided.

[0018] Here, the term "flange portion" is a broad concept that includes not only the so-called flange that is directly connected and fixed to the receiving flange of the device by bolts and nuts, etc., but also a cylindrical part or a protruding part that protrudes from a member and is sandwiched between two members.

[0019] In addition, examples of so-called direct connection between flanges and clamping of flange parts include connection by screwing a screw into a screw hole, joint fastening with a bolt and a nut, and screwing flanges together, and necessary sealing materials such as O-rings and metal gaskets are used between the parts. The "sealing surface" may be provided on either the flange part side or the receiving flange side, and although a process such as polishing may be added if it is provided on the flange part side, it is preferable in terms of shortening the process because it can be formed together with the formation of the spherical shell part through which the beam passes.

[0020] The spherical shell and flange parts can be "integrated" by cutting, but additive manufacturing is preferred, such as the additive manufacturing method for titanium disclosed in Patent Document 2. Additive manufacturing can be used to melt metal powder using a laser or other method, making it possible to manufacture any shape that cannot be achieved by conventional processing methods. By making the spherical shell and flange parts "integrated," the spherical shell part will not crack, as would occur if the spherical shell and flange parts were prepared separately and welded.

[0021] Examples of additive manufacturing for metal materials include powder bed additive manufacturing, which involves laying powder on a surface, additive manufacturing in which powder is melted while being applied or wire is melted, and plasma additive manufacturing. After additive manufacturing, the product is polished if necessary.

[0022] Metal materials that can be used for additive manufacturing include titanium alloys such as 64 titanium alloy (Ti-6Al-4V), aluminum alloys such as Al-10Si-Mg, SUS316L, and Inconel 718. Although 64 titanium is generally used for additive manufacturing, β-titanium alloys with a small Young's modulus can also be additive manufactured and are suitable for use as beam windows.

[0023] The advantages and characteristics of additive manufacturing are: (1) Since additive manufacturing is a method for forming any shape without cutting, when forming complex shapes, the process can be shortened compared to cutting methods, and production yields can be improved. (2) Additive manufacturing can save material by eliminating parts that do not affect mechanical strength.

[0024] In the present invention, by taking advantage of the advantages of the above-mentioned additive manufacturing method, a beam window is provided which "has an optimized spherical shell shape in advance," "has optimized end thickness and angle," and is "integral with the flange portion." Effect of the Invention

[0025] In the present invention, by integrating the spherical shell portion and the flange portion, it is possible to prevent the spherical shell portion from cracking due to distortion when welding to the vacuum flange portion, as in the case of conventional plate beam windows. Also, by making the beam passing portion thin and making the connecting portion connecting the end of the spherical shell portion and the flange portion thicker than the beam passing portion, it is possible to reduce stress at the end where stress is concentrated, and to increase mechanical strength.

[0026] Furthermore, by adopting metal additive manufacturing, it is possible to manufacture thin, arbitrary shapes at low cost using metal materials that are difficult to process. This reduces beam loss and provides a beam window that can withstand a higher pressure difference. In other words, the present invention provides a beam window that can withstand a pressure difference that is about 10 times higher when the inner diameter of the beam window is 200 mm, for example, than the conventional plate method or the method of cutting out from a one-piece structure.

[0027] The technology disclosed in Patent Document 1 is a plate-shaped beam window made of beryllium, while the technology disclosed in Patent Document 2 is a flat window made of titanium. Patent Documents 1 and 2 do not disclose or suggest a beam window that reduces beam loss and can withstand a higher pressure difference, for example, a beam window in which a flange and a spherical shell part are integrally formed by additive manufacturing using titanium, etc., and further, stress is reduced by keeping the beam passing part thin and making the end part where stress is concentrated thicker. In addition, a thin spherical shell part such as that of the present application cannot be connected to a flange part like a conventional plate beam window. [Brief description of the drawings]

[0028] [Figure 1]FIG. 1 shows a first embodiment of a beam window of the present invention, in which FIG. 1(A) is a schematic front view, FIG. 1(B) is a schematic cross-sectional view taken along the line A-A' of FIG. 1(A), and FIG. 1(C) is an enlarged schematic view of the area circled by the dotted line in FIG. [Diagram 2] FIG. 2 is a schematic cross-sectional view at the same position as FIG. 1(B) when the beam window in FIG. 1 is attached to a mounting destination (receiving flange) such as a vacuum vessel with bolts and nuts (not shown). [Diagram 3] FIG. 3 is a schematic front view of a second embodiment of the beam window of the present invention. [Figure 4] Fig. 4(A) is a schematic cross-sectional view taken along line 3A-A' in Fig. 3, and Fig. 4(B) is a schematic cross-sectional view taken along line 3B-B' in Fig. 3. The lattice portion realizes reduction in weight and cost of the flange portion 3b by the cutout 3d. [Diagram 5] FIG. 5 is a rear view of FIG. [Figure 6] FIG. 6 shows a third embodiment of the beam window of the present invention, in which FIG. 3(A) is a schematic front view, and FIG. 6(B) is a schematic cross-sectional view taken along the line A-A' in FIG. [Figure 7] Fig. 7(A) is a schematic cross-sectional view at the same position as Fig. 6(B) when the beam window in Fig. 6 is attached with bolts and nuts (not shown) to a mounting destination (receiving flange) such as a vacuum vessel to which the beam window is attached. Fig. 7(B) is an exploded schematic cross-sectional view of (A), and (C) is an enlarged schematic view of the part circled by the dashed dotted line in (B). [Figure 8] FIG. 8 shows a fourth embodiment of the beam window of the present invention, in which FIG. 8(A) is a partially transparent front view, and FIG. 8(B) is a cross-sectional view taken along the line A-A' of FIG. [Figure 9] FIG. 9 is a schematic cross-sectional view at the same position as FIG. 8(B) when the beam window in FIG. 8 is attached to a mounting destination (receiving flange) such as a vacuum vessel with bolts and nuts (not shown). [Figure 10] FIG. 10 is an explanatory diagram of a conventional plate beam window, in which a beam window is formed by joining a plate to a flange portion. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0029] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Note that the present invention is not limited to the following preferred embodiments. EXAMPLES

[0030] As shown in Figures 1 and 2, the beam window 1 of the first embodiment of the present invention is a one-piece metal body consisting of a spherical shell portion 2 having a beam passing portion 2aa, and a flange portion 3 that is connected to the end of the spherical shell portion 2 and is attached to a receiving flange 4 of the device.

[0031] Examples of the device include a vacuum vessel through which a beam passes, a pressure vessel, an X-ray tube, a beam accelerator, etc. The receiving flange 4 is a flange provided on the device, but the device part is not shown (the same applies below).

[0032] As a metal integral part, an additive manufacturing method is preferable, especially for a large diameter exceeding 200 mm, and for a small diameter smaller than that, it can be formed by cutting. In either case, the thickness of the spherical shell part 2 can be changed, that is, the connecting part 2b where the end of the spherical shell part 2 and the flange part 3 are connected can be made thicker than the beam passing part 2a.

[0033] The spherical shell portion 2 is bowl-shaped. Since the stress generated in the window is inversely proportional to the bulge of the window, by making the spherical shell portion 2 bowl-shaped, the stress generated can be reduced more than in a plate-shaped window. Furthermore, as shown in FIG. 1(C), the connecting portion 2b connecting the flange portion 3 and the end of the spherical shell portion 2 is thicker than the beam passing portion 2a, which further improves the mechanical strength and allows it to withstand a high pressure difference between the windows. Therefore, even a large-diameter beam window exceeding 200 mm has sufficient strength, and furthermore, if it is an integrated metal laminated product, it can be manufactured easily and inexpensively.

[0034] In addition, in Figure 2, the spherical shell portion 2 is concave toward the receiving flange 4 side of the device, but the beam window 1 in Figure 2 may be attached to the receiving flange 4 with the left and right reversed, and the spherical shell portion 2 may be convex toward the device equipped with the receiving flange 4.

[0035] The flange portion 3 is flat on both sides, has holes 3a at equal intervals for passing bolts through, and is connected to the receiving flange 4 with bolts and nuts. The receiving flange 4 side of the flange portion 3 is the sealing surface, and an annular seal groove 4a is drilled in the sealing surface of the receiving flange 4, into which a sealing member 4b such as an O-ring is fitted, and the connection provides a seal and ensures the required degree of vacuum. The holes 3a may be screw holes, and the flange portion 3 and receiving flange 4 may be connected with screws. EXAMPLES

[0036] As shown in Fig. 3-5, the beam window 1a according to the second embodiment of the present invention differs from that of Example 1 in the flange portion 3b. That is, on the front side in Fig. 3, the periphery of the hole 3a is a flat surface 3c, and the space between the holes 3a is a notch 3d, and an annular seal groove 3e is formed in the flange portion 3b on the rear side, providing a seal surface on the rear side of the beam window 1a.

[0037] When sealing surfaces are provided on both the flange portion 3b and the receiving flange 4 of the device, sealing is performed with a metal gasket. On the other hand, when sealing with an O-ring, only one of the seal grooves (seal surface), either the seal groove 3e of the flange portion 3b or the seal groove 4a of the receiving flange 4, is sufficient.

[0038] By providing the notches 3d by simple cuts, recesses, honeycomb structures, slits, etc., while maintaining the connection strength with the receiving flange 4, the amount of metal material used can be reduced and manufacturing costs can be kept down. In particular, in additive manufacturing, these notch shapes can be easily formed. EXAMPLES

[0039] 6 and 7, a beam window 1b according to a third embodiment of the present invention comprises a spherical shell portion 2 having a beam passing portion 2a, and a flange portion 3h that is connected to the end of the spherical shell portion 2 and is attached to a receiving flange 4 of the device by an outer flange body 3f that circumscribes the end of the spherical shell portion 2. The spherical shell portion 2 and the flange portion 3h are an integral laminated metal object.

[0040] That is, the flange portion 3 of the first embodiment is divided into an outer flange body 3f and a flange portion 3h, and a groove 3g for the flange portion 3h is provided on the back surface. This makes it possible to reduce the molding time and the amount of metal used in the case of a layered product. The outer flange body 3f may be manufactured by other processing methods such as cutting. EXAMPLES

[0041] 8 and 9, a beam window 1c according to a fourth embodiment of the present invention has a spherical shell portion connected to a flange portion 3i, which is provided with two spherical shell portions 2 and 2c with a space therebetween, and the space serves as a flow path 2d for the coolant. The spherical shell portions 2 and 2c and the flange portion 3i are integrally laminated metal objects, and are attached to a receiving flange 4 of the device at the flange portion 3i. As in the previous embodiments, the connecting portions 2b between the spherical shell portions 2 and 2c and the flange portion 3i are thicker than the beam passing portions 2a.

[0042] A flow path 3j communicating with the flow path 2d is drilled in the flange portion 3i, but a ring-shaped flow path structure (not shown) for flowing a cooling medium may be provided in the flange portion 3i as well, or only in the flange portion 3i. Examples of the cooling medium include water and helium. Heat generated by the passage of the beam can also be cooled by flowing a cooling medium through the flow path 2d between the spherical shell portions 2 and 2c and the ring-shaped flow path structure of the flange portion 3i. [Explanation of symbols]

[0043] 1 Beam Window 1a Beam window 1b Beam window 1c Beam window 2 Spherical shell part 2a Beam passage section 2b Connecting part 2c Spherical shell part 2d flow path 3 Flange 3a hole 3b Flange part 3c flat surface 3d cutout 3e Seal groove 3f Outer flange body 3g groove 3h Flange 3i Flange 3j Flow path 4 Receiving flange 4a Seal groove 4b Sealing material 11 Conventional plate beam windows 12 Spherical shell part 12a Beam passage section 12b End 12c Dent 13 Joint 15 Flange 16 Receiving flange 16a Sealing material

Claims

1. A beam window attached to a receiving flange of the apparatus, a spherical shell portion having a beam passing portion, the spherical shell portion being connected to an end of the spherical shell portion; A beam window comprising a flange portion attached to the receiving flange by an outer flange body that circumscribes the flange portion, the spherical shell portion and the flange portion being an integral laminated metal object.

2. A beam window attached to a receiving flange of the apparatus, a spherical shell portion having a beam passing portion and a flange portion connected to an end of the spherical shell portion and attached to the receiving flange; The beam window is an integral metal laminate molded product.

3. 3. The beam window according to claim 1, wherein the flange portion is provided with a notch.

4. The beam window according to any one of claims 1 to 3, characterized in that the spherical shell portion connected to the flange portion is provided in two with a space therebetween, and the space serves as a flow path for a cooling medium.

5. 5. The beam window according to claim 1, wherein a cooling medium flows inside the flange portion.

6. 6. The beam window according to claim 1, wherein a connecting portion where the end of the spherical shell portion and the flange portion are connected is thicker than the beam passing portion.

Images