KR100768944B1 - High-flux neutron target system for thermal distribution - Google Patents

Abstract

The present invention relates to a heat dissipation high flux neutron target system. It comprises a rotating body rotatable about the axis of rotation; A plurality of moving target pieces, which are fixed to the periphery of the rotating body, are located on the beam path of the proton beam irradiated from the outside and collide with the proton beam, and are made of a metal which emits neutrons therein by the collision; Rotating the rotating body includes a drive means for causing the moving target pieces to impinge on the proton beam while passing through the beam path of the proton beam.

The heat dissipation high flux neutron target system of the present invention as described above is composed of a plurality of target pieces in which targets colliding with the proton beams are spaced apart from each other, so that even if a high energy proton beam is applied, the abnormal temperature at which the target pieces are separated into a plurality of pieces. There is no excessive rise of, and the target piece is fixed so as to be inclined with respect to the beam line of the proton beam, so that the amount of heat per unit area absorbed by each target piece is small, so there is no need to use a cooling device. Since it can withstand the high current beam above, the utilization range is wide.

Description

High-flux neutron target system for thermal distribution

1 is a schematic view showing a neutron radiography system using a conventional cyclotron.

FIG. 2 is a diagram illustrating a method of obtaining a neutron beam by irradiating a proton beam to a fixed beryllium target in the neutron radiograph system of FIG. 1.

3 is a view schematically showing a heat dissipation high flux neutron target system used in the prior art.

Figure 4 is an exploded perspective view showing the overall configuration of the heat dissipation high flux neutron target system according to an embodiment of the present invention.

FIG. 5 is a diagram illustrating a state in which a proton beam is irradiated to the moving target piece shown in FIG. 4.

FIG. 6 is a partially exploded perspective view illustrating an assembled view of the target system shown in FIG. 4.

FIG. 7 is a partially exploded perspective view of the target system shown in FIG. 4.

<Explanation of symbols for main parts of the drawings>

11: cyclotron 13: acceleration basic body 15: vacuum duct

17: proton beam 19: beryllium target 21: neutron beam

23: focusing machine 25: film cassette 41: rotational target

43: gasket 45: cooling water circulation passage 47: frame

49: shaft 51: heat dissipation high flux neutron target system 53: first plate

53a: proton beam through hole 53b: bearing receptacle 53c: female thread hole

53d: sensor mounting hole 53e: coolant pipe receiving groove 55a: first temperature sensor

55b: second temperature sensor 57: bearing 59: side wall

61: second flat plate portion 61a: neutron beam through hole 61b: cap fitting

61c: Bolt hole 62: Bolt 63: Chamber

65: rotary target part 65a: rotary wheel 65b: moving target piece

65c: Drive shaft fixing hole 65d: Mounting slit 65e: Pin

65f: Pin fitting 65g: Through hole 67: Cooling water circulation pipe

69: motor 69a: drive shaft 71: motor housing

73: Cap 75: Inner Space

The present invention relates to a heat dissipation high flux neutron target system.

Neutron generators for research in the development of neutron detectors, for the assessment of nutrient exposure by neutrons, for nondestructive testing via neutron radiographics, for the study of Boron Neutron Capture Therapy (BNCT), or for the use of neutrons in other industries. Has been developed.

The neutron generator includes a particle accelerator such as a cyclotron and a target which is installed on a beam path of a proton beam emitted from the particle accelerator at high speed and collides with the beam to produce a neutron therein. As is well known, the collision of a proton beam to a target produces a 7Be (p, n) 7B nuclear reaction through which a neutron has a high velocity of kinetic energy and is irradiated to a site induced as a neutron beam.

The metal element used as the target is representatively beryllium, in addition to lithium, tritium, quantum. It also uses tungsten or iron when using large accelerators. However, beryllium is mainly used because beryllium has the best performance in terms of neutron generation efficiency and thermal characteristics.

1 is a schematic diagram illustrating a neutron radiograph system using a small cyclotron. Radiographic refers to radiographs used for nondestructive testing. For reference, when the concentrator 23 is removed in the configuration shown in FIG. 1, the neutron generator is provided.

In any case, as shown in FIG. 1, the proton beam 17 accelerated in the acceleration main body 13 of the cyclotron 11 travels through the vacuum duct 15 and stands in the vertical direction of the beryllium target 19. When colliding, the neutron beam 21 is emitted from the beryllium target 19. The neutron beam 21 moves inside the concentrator 23 and penetrates a photographing object (not shown), and then projects the image onto the film inserted in the film cassette 25. The beryllium target 19 is fixed perpendicular to the beam line of the proton beam.

FIG. 2 is a view showing a state in which the neutron beam 21 is obtained by irradiating the proton beam 17 to the beryllium target 19 shown in FIG.

As shown in FIG. 2, when the proton beam 17 is irradiated to the fixed beryllium target 19, neutrons are emitted from the beam irradiation site A of the beryllium target 19, and the heavy beam beam according to the above theory. (21) is obtained. In some cases, the target and the beamline may be tilted instead of vertically arranged. However, the target is generally orthogonal to the beamline in consideration of the parallel straightness of the neutron beam.

On the other hand, since the proton beam basically has high energy and the irradiation site is concentrated in one place, even if the amount of energy is increased a little, the fixed target is easily thermally damaged (the beam irradiation site is melted) so that neutrons can no longer be generated. do. In order to obtain a sufficient amount of neutron beams to be used, it is necessary to irradiate proton beams with a certain amount of energy, but the energy of the proton beams cannot be increased without any measures due to the above-described thermal damage problems.

As a result, in order to stably obtain the neutron beam through the neutron generator, it is necessary to lower the energy of the proton beam or to prevent thermal damage of the fixed target.

However, if the energy of the proton beam is lowered, the amount of neutron generation does not meet the need, so that an additional cooling device is added to the target to increase the energy of the proton.

For reference, according to the experiments of the present inventors, after irradiating the beryllium target 19 fixed to the beryllium target 19 for 10 minutes in the absence of any cooling device, the beam irradiation site A was melted and drilled. Could know.

As described above, since the neutron generator having the fixed target needs to be easily thermally damaged or a high-capacity high-efficiency cooling device as long as the target is fixed, in order to lower the probability of thermal damage and also reduce the cooling load of the cooling device. A neutron generator using a mobile target as shown in the drawings has also been developed.

Since the neutron generator having such a mobile target has less energy of the beam colliding per unit area than the fixed target, the neutron generator has a lower risk of thermal damage and a lower required cooling capacity than the fixed target.

3 is a view schematically showing a heat dissipation high flux neutron target system used in the prior art. The rotary target 41 shown in FIG. 3 is the movable target described above.

As shown in the drawing, the conventional target system includes a shaft 49 that is axially rotated by external power, a disk-shaped rotating target 41 that is fixedly rotated to the shaft 49, and the rotating target 41. And a frame 47 rotatably supporting the shaft 49.

In addition, a gasket 43 is provided between the shaft 49 and the rotational target 41 and the frame 47. The gasket 43 rotatably supports the shaft 49 and the rotational target 41 and serves as a seal to block the cooling water, which will be described later, from leaking.

In addition, the cooling water circulation passage 45 is provided at the rear of the rotary target 41. The cooling water circulation passage 45 is a space provided between the frames 47 and passes the cooling water therein. The cooling water passes through the cooling water circulation passage 45 and cools the rotating target 41 heated by the proton beam 17.

However, in the conventional target system configured as described above, since the rotating target 41 continuously rotates, the overall beam irradiation portion A is wide (when a proton beam of the same energy is applied) so that the fixed target 19 of FIG. Although the probability of heat damage is low, the cooling water may leak. Since even a small amount of coolant leaks, expensive neutron generators may not work, so the cost of cooling is high and always be prepared for leakage of coolant.

The present invention has been made to solve the above problems, and since the targets colliding with the proton beams are composed of a plurality of target pieces spaced apart from each other, even if a high-energy proton beam is applied, each target piece is dissipated as long as the heat is distributed to the plurality of target pieces. There is no fear of overheating, and the target piece is fixed so as to be inclined with respect to the beam line of the proton beam, so that the amount of heat per unit area absorbed by each target piece is small and there is no need to use a cooling device. Since it can withstand the high current beams above, an object of the present invention is to provide a heat dissipation high flux neutron target system that is widely used.

The heat dissipation high flux neutron target system of the present invention for achieving the above object comprises: a rotating body rotatable about a central axis of rotation; A plurality of moving target pieces, which are fixed to the periphery of the rotating body, are located on the beam path of the proton beam irradiated from the outside and collide with the proton beam, and are made of a metal which emits neutrons therein by the collision; Rotating the rotating body includes a driving means for causing the moving target pieces to pass through the beam path of the proton beam and collide with the proton beam, the axis of rotation of the rotor is parallel to the beam path of the proton beam.

In addition, the rotating body is a disk or a ring-shaped member having a certain outer diameter, the moving target pieces are characterized in that the spaced apart from each other at regular intervals.

In addition, the moving target piece is characterized in that inclined in the range of 20 degrees to 40 degrees with respect to the beam path of the proton beam.

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The moving target piece may be any one of beryllium, lithium, tritium, deuterium, tungsten and iron.

In addition, the target system includes a proton beam through-hole for accommodating the rotating body therein and allowing a proton beam irradiated from the outside to reach the moving target piece, and a neutron generated from the moving target piece. And a chamber in which a neutron beam through hole for passing the beam is formed.

The chamber may include a first temperature sensor that senses the temperature of the moving target piece that passes through the beam line of the proton beam and collides with the proton beam, and a temperature of the moving target piece that approaches the proton beamline for collision with the proton beam. A second temperature sensor for sensing is further provided.

The first and second temperature sensors may be equally spaced apart from each other with the proton through-holes interposed therebetween and positioned at the same distance from the central axis of rotation of the rotating body.

The first and second temperature sensors may be positioned within an angle range of 20 degrees to 50 degrees with respect to the central axis of rotation of the rotating body.

In addition, the chamber, characterized in that the cooling means for cooling the temperature of the chamber is further provided.

Hereinafter, one embodiment according to the present invention will be described in detail with reference to the accompanying drawings.

Figure 4 is an exploded perspective view showing the overall configuration of the heat dissipation high flux neutron target system according to an embodiment of the present invention.

Referring to the drawings, the heat dissipation high flux neutron target system 51 according to the present embodiment includes a chamber 63 that provides an internal space (75 of FIG. 6), and a rotatable inside the chamber 63. A rotary target unit 65 to be installed, a motor 69 mounted outside the chamber 63 and rotating the rotary target unit 65, and a cooling water circulation pipe 67 for cooling the chamber 63. It is configured to include.

The chamber 63 has a plate shape having a predetermined thickness and is fixed to an inner surface of the first flat portion 53 and the first flat portion 53 having a proton beam through hole 53a provided at one side thereof. The proton beam through hole 53a in the inner region thereof, the side wall portion 59 having a constant diameter, and the side wall portion 59 coupled to the side wall portion 59 and spaced apart from the first flat portion 53 in parallel with the proton. The second flat plate portion 61 has a neutron beam through hole 61a at a position corresponding to the beam through hole 53a.

The side wall portion 59 is a ring-shaped member having a constant diameter and an inner space for receiving the rotary target portion 65 between the first plate portion 53 and the second plate portion 61 (75 in FIG. 6). To provide.

In particular, the chamber 63 may be anodized in black so as to have an insulating function and absorb radiant heat generated from the rotation target part 65.

In addition, a bearing accommodation member 53b is formed at the center of the first flat plate 53. The bearing receptacle 53b is a hole for fixing the bearing 57. The bearing 57 serves to support the drive shaft 69a of the motor 69.

Therefore, the motor 69 is fixed to the outer center of the first plate portion 53 in the state in which the drive shaft 69a extends through the bearing 57 to the interior space of the chamber 63, and then the rotary target portion ( It is fixed to the drive shaft fixing hole 65c which is the center of rotation of 65. As shown in FIG. As a result, when the motor 69 is driven, the rotary target part 65 rotates in the chamber 63.

Meanwhile, first and second temperature sensors 55a and 55b are mounted on the first flat plate 53. The first and second temperature sensors 55a and 55b are non-contact temperature sensors, and are spaced apart at equal intervals on both sides of the proton beam through hole 53a. That is, it is located in the opposite direction by the same angle x from an imaginary straight line connecting the drive shaft 69a and the proton beam through hole 53a of the motor 69. In addition, the distance from the center of the bearing accommodation port 53b of the first and second temperature sensors 55a and 55b is the same.

The first and second temperature sensors 55a and 55b are for detecting the temperature of the moving target piece 65b while the rotary target part 65 rotates.

In addition, a coolant pipe accommodation groove (53e of FIG. 7) is formed on an outer surface of the first flat plate 53 to accommodate the coolant circulation pipe 67. The cooling water pipe accommodation groove 53e will be described with reference to FIG. 7.

Reference numeral 71 denotes a motor housing. The motor housing 71 shields the magnetic field or electric field generated from the motor so as not to affect the proton beam 17 by accommodating the motor 69 therein.

Similarly to the first flat plate 53, the second flat plate portion 61 has a predetermined thickness and has a cap fitting hole 61b that is blocked by a cap 73 at the center thereof. In addition, the neutron beam through hole 61a has a diameter larger than that of the proton beam through hole 53a to allow the neutron beam 21 generated from the moving target piece 65b to smoothly escape from the chamber 63.

The first plate portion 53 and the second plate portion 61 are coupled through a plurality of bolts 62 with the side wall portion 59 therebetween. To this end, a plurality of female screw holes 53c are provided in the edge portion of the first flat plate portion 53, and bolt holes 61c are provided in the edge portion of the second flat plate portion 61. Therefore, the chamber 63 is formed by aligning the bolt hole 61c with the female screw hole 53c, then fitting the bolt hole 61c through the bolt hole 61c and screwing into the female screw hole 53c.

On the other hand, the rotary target portion 65 is in the form of a ring, the center of rotation of the rotary wheel 65a is provided with a drive shaft fixing hole 65c, and a plurality of movements fixed to the periphery of the rotary wheel 65a It consists of the target piece 65b. The rotary target portion 65 resembles a turbine wheel. Indeed, the moving target piece 65b may be manufactured in an airfoil like a turbine blade rather than a flat plate, which will be described later.

In any case, the drive shaft fixing hole 65c of the rotary wheel 65a is fixed to the drive shaft 69a of the motor 69 to rotate during operation of the motor. The rotational speed or direction of rotation of the rotary wheel 65a can be adjusted as much as possible.

The moving target piece 65b is a plate-shaped member made of beryllium and takes the form of a rectangular plate as shown in FIG. The number or size of the moving target piece 65b may vary depending on the case. For example, the size of the moving target piece 65b may be manufactured to be 2.2 cm wide, 4.5 cm long, and 0.025 cm thick.

The moving target piece 65b is located between the proton beam through hole 53a and the neutron beam through hole 61a to impinge on the proton beam 17 entering through the proton beam through hole 53a. Therefore, when the proton beam 17 is irradiated to the proton beam through-hole 53a while the rotational target portion 65 is rotated at a constant speed, the proton beam 17 collides evenly on each moving target piece 65b. The neutron beams 21 generated from the respective moving target pieces 65b are continuously emitted through the neutron beam through holes 61a.

In particular, the moving target piece 65b is inclined about 20 to 40 degrees with respect to the irradiation direction of the proton beam 17. By tilting the moving target piece 65b in this way, the irradiation area of the proton beam reaching the surface of the moving target piece 65b can be increased to reduce the energy applied by the proton beam per unit area of the moving target piece 65b.

FIG. 5 is a diagram illustrating a state in which a proton beam is irradiated to the moving target piece shown in FIG. 4.

Referring to the drawings, it can be seen that the moving target piece 65b collides with the proton beam while being inclined at an angle z with respect to the beamline of the proton beam 17. The inclination angle z is 20 degrees to 40 degrees, preferably about 30 degrees.

Since the moving target piece 65b is inclined as described above, the irradiation area of the proton beam 17 reaching the moving target piece 65b increases and the density of the beam decreases. The increase in the irradiation area of the proton beam having a constant energy means that the amount of energy received per unit area of the moving target piece 65b is small. That is, the proton beam 17 of greater energy can be irradiated than when the moving target piece is not inclined.

In any case, since the moving target piece 65b is inclined with respect to the beamline of the proton beam 17, the energy of the proton beam 17 can be increased to obtain a more sufficient neutron beam 21.

FIG. 6 is a partially exploded perspective view illustrating an assembled view of the target system shown in FIG. 4.

As shown in the drawing, the first flat plate portion 53 and the second flat plate portion 61 are coupled to each other by a bolt 62 with the side wall portion 59 interposed therebetween. The side wall portion 59 provides an inner space 75 between the first plate portion 53 and the second plate portion 61 and accommodates the rotary target portion 65.

In addition, the drive shaft 69a of the motor is inserted into and fixed to the drive shaft fixing hole 65c of the rotary wheel 65a. Accordingly, as the motor 69 is driven, the rotary target portion 65 rotates in the direction of the arrow or vice versa.

On the other hand, a plurality of mounting slits 65d are formed at the edge of the rotary wheel 65a. The mounting slits 65d receive and fix the moving target piece 65b so as to be parallel to each other and to form the same spacing. In addition, a pin mounting hole 65f is provided between the respective mounting slits 65d. The pin mounting opening 65f penetrates through the thickness direction of the rotary wheel 65a as a hole for pinning the pin 65e. In addition, the pin 65e is inserted into the pin mounting opening 65f to fix the moving target piece 65b to the mounting slit 65d.

The moving target piece 65b has a rectangular shape having a constant thickness and has a through hole 65g at its lower side. The through hole 65g is a hole through which the pin 65e passes, and forms a straight line with the pin fitting port 65f in a state where the moving target piece 65b is inserted into the mounting slit 65d.

Therefore, when the pin 65e is inserted through the pin mounting opening 65f while the moving target piece 65b is inserted into each mounting slit 65d, the moving target piece 65b is fixed to the rotary wheel 65a. This is done. In order to replace the moving target piece 65b as needed, the moving target piece 65b may be lifted out with the pin 65e removed.

The first temperature sensor 55a and the second temperature sensor 55b provided at both sides of the proton beam through hole 53a measure the temperature of the moving target piece 65b which rotates in the direction of the arrow E. . The first temperature sensor 55a senses the temperature of the moving target piece 65b immediately after being heated by the proton beam, and the second temperature sensor 55b moves toward the proton beam through hole 53a, that is, the proton beam. The temperature of the moving target piece 65b before this collision is measured.

As described above, by measuring the temperature immediately after the collision with the proton beam of the moving target piece 65b and immediately before, the degree of cooling during the rotation of the moving target piece 65b can be grasped. The energy level of the beam can be adjusted or the cooling means can be determined. The positions of the first and second temperature sensors 55a and 55b are closer to the proton beam through hole 53a.

FIG. 7 is a partially exploded perspective view of the target system shown in FIG. 4.

Referring to the drawings, it can be seen that the first and second temperature sensors 55a and 55b are screwed into the sensor mounting hole 53d. Of course, the coupling method of the temperature sensor may vary depending on the case.

In addition, a coolant pipe accommodation groove 53e is provided on an outer surface of the first flat plate 53. The cooling water pipe receiving groove 53e is a groove for receiving the cooling water circulation pipe 67 and its bottom surface is brought into close contact with the cooling water circulation pipe 67.

The cooling water circulation pipe 67 is a general cooling means for cooling the first flat plate 53 by circulating the cooling water therein. As described above, since the chamber 63 absorbs radiant heat generated from the rotary target portion 65, the chamber 63 may be cooled as a whole by cooling the first flat portion 53. If necessary, the cooling water circulation pipe 67 may not be operated.

As mentioned above, although this invention was demonstrated in detail through the specific Example, this invention is not limited to the said Example, A various deformation | transformation is possible for a person with ordinary knowledge within the scope of the technical idea of this invention. .

Heat dissipation high flux neutron target system of the present invention made as described above is composed of a plurality of target pieces spaced apart from each other the target colliding with the proton beam, so that even if a high-energy proton beam is applied, heat is distributed to the plurality of target pieces There is no fear of overheating each target piece, and the target piece is fixed so as to be inclined with respect to the beam line of the proton beam, so that the amount of heat per unit area absorbed by each target piece is small so that it is not necessary to use a cooling device. In this case, it can endure high current beams of more than ㎃ class, so it is widely used.

Claims (10)

A rotating body rotatable about an axis of rotation; A plurality of moving target pieces, which are fixed to the periphery of the rotating body, are located on the beam path of the proton beam irradiated from the outside and collide with the proton beam, and are made of a metal which emits neutrons therein by the collision; And driving means for rotating the rotating body so that the moving target pieces impinge on the proton beam while passing through the beam path of the proton beam. And a central axis of rotation of the rotating body parallel to the beam path of the proton beam. The method of claim 1, The rotating body is a disk or a ring member having a certain outer diameter, The moving target pieces are heat dissipation high flux neutron target system, characterized in that spaced apart from each other at regular intervals on the periphery of the rotating body. The method of claim 2, The moving target piece is inclined within a range of 20 degrees to 40 degrees with respect to the beam path of the proton beam, heat dissipation high flux neutron targeting system. delete The method according to any one of claims 1 to 3, The moving target piece is any one of beryllium, lithium, tritium, quantum, tungsten, iron, heat dissipation high flux neutron target system. The method of claim 1, The target system includes a proton beam through-hole for accommodating the rotating body therein and passing to one side a proton beam irradiated from the outside to reach the moving target piece, and a neutron beam generated from the moving target piece. A heat dissipation high flux neutron target system, further comprising a chamber in which a neutron beam through hole is formed. The method of claim 6, In the chamber, a first temperature sensor for sensing the temperature of the moving target piece passing through the beam line of the proton beam and collided with the proton beam, and for sensing the temperature of the moving target piece in proximity to the proton beamline for collision with the proton beam Heat dissipation high flux neutron target system, characterized in that the second temperature sensor is further provided. The method of claim 7, wherein The first and second temperature sensors are heat dissipation high flux neutron target system, characterized in that spaced apart from each other with the proton through-holes at the same distance from the center of rotation of the rotating body. The method of claim 8, The first and second temperature sensors are heat dissipation high flux neutron target system, characterized in that located within an angle range of 20 degrees to 50 degrees with respect to the center of rotation of the rotating body. The method of claim 6, The chamber, the heat dissipation high flux neutron target system, characterized in that further provided with cooling means for cooling the temperature of the chamber.

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