JP2006284344A - Secondary charged particle producing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently, continuously and quickly cool and remove a plenty of heat generated by nuclear spallation reaction in a metal target generating secondary charged particles by introducing proton beam. <P>SOLUTION: A secondary charged particle generation target 1 is formed in a disk shape of which the radius direction is arranged vertically and fixed to horizontal shaft 3 and rotated. A part of the lower side is directly submerged in cooling water 11 stored in a water tank 6 and overflowing so that the submerged part 22 is cooled by water. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a secondary charged particle generator in a nuclear spallation experiment facility using a proton beam of a high-intensity acceleration facility.

  Equipment that continuously generates (5000 hours) secondary charged particles (π meson, kaon, muon, neutrino, antiproton, etc.) used for experiments by colliding a high-intensity proton beam (12 kW) with the target In the case, in the target, nuclear fragmentation occurs after collision, and heat (about 10 kW) corresponding to incident energy is generated together with secondary charged particles. A method for efficiently removing this heat has been demanded.

  In Patent Document 1, as a nuclear reaction target, a beam is received on the surface of a cylinder on which a target material is deposited, and when it is consumed, the cylinder is moved in parallel. It is introduced that makes it possible.

  Patent Document 2 shows a structure capable of obtaining a high specific strength and high thermal conductivity as a rotating target for an X-ray tube, and a carbon composite that excels in specific strength and thermal conductivity when the thermal energy generated by colliding with the target is shown. A structure in which materials are stacked is introduced.

  Patent Document 3 introduces a method for cooling a target chamber provided on the back surface of a target chamber in order to efficiently remove thermal energy due to irradiation energy of a proton beam as an 18F manufacturing target.

  Patent Document 4 introduces the use of a disk-shaped target having a high atomic number and a high melting point as an electron beam irradiation device in order to prevent an excessive heat load on the electron beam transmitting portion.

  As a cooling structure for the target for generating secondary charged particles, 1) a structure in which the heat generated from the central part is cooled in the peripheral part by the fixed target method, and 2) a structure in which the heat generating part is dispersed by changing the place where the beam hits. Things are known.

  In addition, a structure in which a cooling water flow path is provided to indirectly cool a target for generating secondary charged particles via a heat transfer metal and the entire apparatus is rotated is known.

JP-A-8-15500 JP-A-8-250053 JP-A-9-54196 JP 2000-249800 A

  When trying to generate secondary charged particles by irradiating the target with a continuous incident proton beam, there is a risk of deformation or melting of the material if it concentrates on a part of the target. As a countermeasure, heat transfer around the fixed target There have been considered the concept of providing an efficient cooling heat bath block, a device for rotating the target to prevent the heat generation from concentrating, and the cooling target immersed in water. Furthermore, a method of cooling (about 1 kW) by circulating cooling water through a metal having good heat conductivity has been studied. However, no secondary charged particle target heat removal method has been established that can efficiently and continuously remove a large amount of heat generated from the spallation reaction by the collision of a high-intensity proton beam.

  When the target disk is placed in a water tank and rotated, an air entrainment phenomenon occurs, and the contact area between the target surface and the cooling water decreases, resulting in a decrease in cooling efficiency.

  When the target is irradiated with a proton beam, the heat generated by activation increases as the amount of secondary charged particles generated in the nuclear spallation reaction increases in the direction of the target disk thickness. As a result, it was necessary to reduce the plate thickness, increase the disk diameter, or increase the rotational speed in order to suppress the amount of heat generated.

  In view of such points, the present invention aims to provide a secondary charged particle generator equipped with a secondary charged particle target capable of efficiently and rapidly removing a large amount of heat generated from a nuclear fragmentation reaction. To do.

The present invention relates to a secondary charged particle generator including a metallic secondary charged particle generation target that generates a secondary charged particle by injecting a proton beam from a high-intensity accelerator.
The secondary charged particle generation target is formed in a disk shape, and the radial direction is arranged in the vertical direction, and a drive device for rotating the secondary charged particle generation target is provided, and the secondary charged particle generation target is provided below the secondary charged particle generation target. Provided is a secondary charged particle generator characterized in that a water tank is provided for performing water cooling by immersing directly in cooling water storing a part of the side.

  Further, the secondary charged particle generating target provides a secondary charged particle generating device characterized in that a disk-like outer peripheral end portion has a triangular shape or an arc shape.

  The secondary charged particle generation target is constituted by a plurality of target plates in the thickness direction thereof, and is driven integrally. The secondary charged particle generation apparatus is provided.

  In addition, the target plate arranged on the proton beam incident side, the target plate arranged on the side from which secondary charged particles are extracted, and the target plate arranged in the middle are successively made thinner from the proton beam incident side. A secondary charged particle generator is provided.

  In the present invention, since a part of the secondary charged particle target rotating as described above is directly immersed in the cooling water, a large amount of heat generated from the nuclear fragmentation reaction is efficiently and rapidly removed. A secondary charged particle generator including a secondary charged particle target that can be provided can be provided.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a diagram for explaining the concept of the first embodiment. In FIG. 1, a secondary charged particle target 1 is formed in a disc (disk) shape, is arranged in a vertical direction (vertical direction), and is rotated by a rotating horizontal axis 3. A proton beam 9 as an energy beam is irradiated on the upper part of the secondary charged particle target 1 from the thickness direction. The secondary charged particle target 1 receives the proton beam 9 and generates or passes the proton beam 9, the secondary charged particle 10, and the secondary charged particle 10 as reflected energy rays. When this reflected energy ray is generated, the secondary charged particle target 1 generates heat and becomes a heat generating portion 21, and the upper portion is heated and transferred to the lower portion.

  A part of the lower side of the secondary charged particle target 1 becomes an immersion part 22 and is directly immersed in the cooling water 11. As a result, the heat generating portion 21 of the rotating secondary charged particle target 1 is continuously cooled by the cooling water 11. The part to be immersed is shown as 22.

  In order to increase the cooling efficiency, the upper end portion of the secondary charged particle target 1 is irradiated with the proton beam 9, and the secondary charged particle target 1 is rotated (in this example, counterclockwise) to continuously cool. It is a method to do.

  2 and 3 are configuration diagrams showing the configuration of FIG. 1 in detail. 2 is a front view, and FIG. 3 is a side view.

  In these figures, the secondary charged particle target 1 is fixed to the horizontal axis 3 arranged in the horizontal direction by a key and rotates integrally with the horizontal axis 3. The horizontal shaft 3 has bearings 2 attached to both ends thereof, and is held by brackets 24 provided on the main body 90 via the bearings 2. A set of bevel gears 4 (4A, 4B) is provided at one end of the horizontal shaft 3, and the bevel gear 4B is driven by the vertical axis 5. The vertical axis 5 is connected to a drive source (not shown) and is driven to rotate. In this way, a drive device (drive means) is configured. Accordingly, the secondary charged particle target 1 is rotated by the driving device.

  FIG. 3 shows a proton beam spot 8 irradiated with the proton beam 9. The proton beam spot 8 is located on the side of the upper part of the secondary charged particle target 1.

  FIG. 2 shows a water tank 6 for immersing the secondary charged particle target 1. A water tank 6 in which cooling water 11 is stored is provided below the secondary charged particle target 1, and cooling water is supplied from a cooling water supply pipe 7. The cooling water 11 overflows from the water tank 6.

  A part of the lower side of the secondary charged particle target 1 (immersion part 22) is directly immersed in the cooling water 11.

  The rotating secondary charged particle target 1 is irradiated near the cooling water, and the immersion part 22 is immediately cooled by the cooling water immediately. This cooling takes place rapidly and continuously.

  As described above, according to the present embodiment, by rotating the secondary charged particle target 1, it is possible to avoid local concentration of heat generation, and the secondary charged particle target 1 is cooled to the cooling water 11 of the water tank. By soaking, the cooling efficiency can be further improved, and stable secondary charged particles can be supplied over a long period of time.

  In this way, the secondary charged particle target 1 is held by the horizontal axis 3, the bearing 2, and the bracket 24, rotated by transmitting the rotational driving force by the vertical axis 5 and the bevel gear, and the secondary charged particle target 1 is further rotated. By providing a water tank 6 for direct cooling and a cooling water supply pipe 7 for continuous cooling, continuous cooling can be performed, and as a result, heat generation dispersion at the target spot 8 and a large amount of generated heat can be efficiently and continuously removed. The secondary charged particle generation target 1 that can be provided can be provided.

  A second embodiment will be described with reference to FIGS. 4 and 5. The main configuration is the same as that of the first embodiment, and the description of the first embodiment is adopted for the description thereof. The same applies to the other embodiments.

  As shown in FIG. 4 (see FIG. 4A and FIG. 4B), when a disk having a right-angled end as in the structure of the first embodiment is used as the secondary charged particle target 1, the rotation is performed. As the speed increases, ambient air 12 may be entrained in the target end 14.

  The entrained air 12 becomes bubbles 13 and rotates along the secondary charged particle target 1 in the cooling water 11 and is discharged to the opposite side.

  FIG. 5 provides a structure that prevents this air entrainment. FIG. 5A shows a front view, and FIG. 5B shows a side view. In FIG. 5, the secondary charged particle target 1 has a circumferential end as a triangular end target 15. That is, the disk-shaped outer peripheral end is triangular. R may be provided in part. By doing so, the entrainment of the surrounding air 12 at the target end 14 can be made extremely small. Therefore, the number of bubbles 13 rotating with the triangular end target 15 of the secondary charged particle target 1 is extremely small.

  Example 3 is shown in FIG. FIG. 6A is a front view, and FIG. 6B is a side view. The configuration shown in FIG. 6 employs a semicircular end target 16 instead of the triangular end target 15 of the second embodiment. The effect is the same as that shown in FIG. That is, in this configuration, the disk-like outer peripheral end portion has an arc shape (including a semicircular diameter).

  In this way, as shown in FIG. 5 or FIG. 6, in order to improve the heat removal property of the secondary charged particle target 1, the structure of the outer periphery of the disk is changed from a flat structure to a triangle or semicircular structure. The secondary charged particle generation target that can suppress the jumping of water and the entrainment of air when the water enters the water and can improve the cooling efficiency can be supplied.

  FIG. 7 shows a fourth embodiment. FIG. 7A is a front view, and FIG. 7B is a side view.

  In this embodiment, the secondary charged particle target 1 is divided into a plurality of target plates 1a, 1b, 1c, 1d, in order to greatly increase the contact area of the secondary charged particle target 1 with the cooling water 11 and improve the cooling effect. 1e. That is, the division | segmentation target board 1 is employ | adopted and the gap | interval 17 is provided among them. The cooling water 11 flows into the gap 17.

  Thus, by forming the secondary charged particle target 1 using the plurality of target plates 1a, 1b, 1c, 1d, and 1e divided in the plate thickness direction, the heat generation distribution in the plate thickness rear portion is high. As the cooling effect increases, the diameter of the disk and the rotational speed of the secondary charged particle target 1 can be suppressed.

  Thus, by adopting a plurality of target plates 1a, 1b, 1c, 1d, and 1e, that is, by dividing in the plate thickness direction, the cooling area can be increased and the cooling efficiency can be improved. A secondary charged particle generation target can be provided.

  8 and 9 show a fifth embodiment. As shown in FIG. 8, when the split target configuration is adopted, the effect is great. However, when the proton beam 9 is irradiated to the target plate 17 (17a, 17b, 17c) one after another, the secondary charged particles 10 increase and the heat increases. The amount of heat generated increases as the target plate in the latter stage spreads.

  As a countermeasure, the example shown in FIG. 9 is adopted. In the example of FIG. 9, the uneven thickness target plate 18a disposed on the incident side (entrance side) of the proton beam 9 and the uneven thickness target disposed on the side from which the secondary charged particles 10 are extracted (exit side). The thicknesses of the non-uniform thickness target plates 18b and 18c arranged in the middle of the plate 18e are sequentially reduced from the proton beam incident side.

  The plate thickness is 18a> 18b> 18c> 18d> 18e. With this configuration, it is possible to equalize the amount of heat generated by each of the uneven thickness target plates 18a, 18b, 18c, 18d, and 18e. That is, in this example, the secondary charged particle target 1 is configured by using a plurality of non-uniform plate thickness division targets 18.

  As described above, the secondary charged particle generation apparatus 100 including the metallic secondary charged particle generation target that generates the secondary charged particles 10 by entering the proton beam 9 from the high-intensity accelerator generates the secondary charged particles. The target 1 is formed in a disk shape, the radial direction is arranged in the vertical direction, a drive device that rotates the secondary charged particle generation target 1 is provided, and a lower part of the secondary charged particle generation target is stored. A water tank 6 that is directly immersed in the cooling water 11 to perform water cooling is provided.

The conceptual diagram of the Example of this invention. The front view which shows the detailed structure of the Example of this invention. The side view of FIG. The figure explaining the problem which Example 1 has. It is a figure which shows the structure of another Example, FIG. 5 (a) is a front view, FIG.5 (b) is a side view. It is a figure which shows the structure of another Example, FIG. 6 (a) is a front view, FIG.6 (b) is a side view. It is a figure which shows the structure of another Example, Fig.7 (a) is a front view, FIG.7 (b) is a side view. The figure explaining the problem which Example 4 has. It is a figure which shows the structure of another Example, Fig.9 (a) is a front view, FIG.9 (b) is a side view.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Secondary charged particle target, 2 ... Bearing, 3 ... Horizontal axis, 4 ... Bevel gear, 5 ... Vertical axis, 6 ... Water tank, 7 ... Cooling water supply piping, 8 ... Proton beam spot, 9 ... Proton beam, 10 ... secondary charged particles, 11 ... cooling water, 12 ... air, 13 ... air bubbles, 14 ... target end, 15 ... triangular end target, 16 ... semicircular end target, 17 ... target plate, 18 ... non-uniform plate thickness division Target, 21 ... Heat generating part, 22 ... Dipping part, 24 ... Bracket, 90 ... Main body, 100 ... Secondary charged particle generator.

Claims (4)

In a secondary charged particle generator equipped with a metallic secondary charged particle generation target that generates a secondary charged particle by injecting a proton beam from a high-intensity accelerator,
The secondary charged particle generation target is formed in a disk shape, and the radial direction is arranged in the vertical direction, and a driving device for rotating the secondary charged particle generation target is provided, and the secondary charged particle generation target is provided below the secondary charged particle generation target. A secondary charged particle generator, characterized in that a water tank is provided for performing water cooling by directly immersing in a cooling water storing a part of the side.   2. The secondary charged particle generating apparatus according to claim 1, wherein the secondary charged particle generating target has a disk-like outer peripheral end that is triangular or arcuate.   2. The secondary charged particle generation apparatus according to claim 1, wherein the secondary charged particle generation target is constituted by a plurality of target plates in the thickness direction and is integrally driven. 4. The target plate arranged on the proton beam incident side, the target plate arranged on the side from which secondary charged particles are taken out, and the target plate arranged in the middle are successively thinner from the proton beam incident side. Secondary charged particle generator characterized by being made.

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