JP2002162475A - Fluorescent beam monitor and its manufacturing method, and charged particle accelerator provided with fluorescent beam monitor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a beam monitor capable of preventing discharging by charged electrification of a fluorescent beam monitor, installed on a beam passing path of a charged particle accelerator, and measuring accurately the position, the size and the shape of the beam. SOLUTION: Many holes are formed on a conductive material, installed on a fluorescent screen in physically and chemically adhesive state, to measure the position and the shape of the beam, and the conductive material is grounded, to prevent discharge caused by the electrification.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluorescent beam monitor for monitoring the position, shape, size, etc. of a charged particle beam in a charged particle accelerator for elementary particle physics research, industrial use, medical use, and the like.

[0002]

2. Description of the Related Art It has long been known that light is emitted from a material when it is exposed to high-speed charged particles, and a fluorescent beam monitor using the same is widely used in charged particle accelerators. FIG. 9 is a sectional view of an apparatus provided with a generally used fluorescent beam monitor 10a. The monitor device is composed of a fluorescent plate 10b that emits light, a support 30 supporting the light, a support rod 31, a moving mechanism 32 for driving them, and a viewing window 33 for observing a beam in the atmosphere. Alternatively, the fluorescent beam monitor 10a alone is often referred to as a fluorescent beam monitor. Reference numeral 100 denotes a beam, which indicates a passage therethrough.

Next, the operation will be described. Fluorescent plate 10b
Is generally made of ceramics. When a group of high-speed charged particles, that is, a beam hits the fluorescent screen 10b, light is generated from the hit position and is observed through the viewing window 33. Since the light intensity is proportional to the beam intensity, the intensity distribution and shape of the beam cross section can be determined by appropriately processing the observed light. When the energy of the beam is high, the radiation emitted from the fluorescent screen 10b is strong, and cannot be directly observed through the viewing window 33, but can be remotely observed by installing a television camera. In the case of a high energy beam, the fluorescent plate 10
Aluminum may be used instead of ceramics for the material of b. After the beam observation is completed, the fluorescent beam monitor 10a is removed from the beam passage 100 by the moving mechanism 32 so as not to hinder the beam passage.

[0004]

Since the conventional fluorescent beam monitor is configured as described above, it is necessary to obtain information on the beam shape, beam cross-sectional diameter, and the highest intensity portion of the beam. It is necessary to make a scale on the fluorescent plate 10b. When the fluorescent plate 10b is made of aluminum, it is possible to cut the scale. However, in the case of a hard material such as ceramics, the scale cannot be formed. For example, writing the scale with a pen or the like is avoided because the degree of vacuum is deteriorated. So
There was a problem that the above-mentioned various information of the beam could not be obtained accurately. In the case of insulators such as ceramics,
In the case of charged particles having such a low energy that the beam cannot pass through the ceramics, electric charge is accumulated on the ceramics to cause a discharge, which hinders the observation of the beam. In order to solve such a problem, for example, Japanese Patent Publication No. 5-23718 discloses a fluorescent screen monitor in which a conductive scale member electrically connected to a conductive support member is installed on a fluorescent screen. However, in this case, there is a case where the fluorescent plate and the scale member are not always in close contact with each other. In a case where the beam energy is too low to pass through the fluorescent plate, the conductive scale member is in close contact with the fluorescent plate. Charges may be charged on the phosphor plate in places where it has not been done, and the beam may appear to flow on the phosphor plate due to the effects of discharge, etc., and the exact position, shape, and intensity distribution of the beam cannot be observed. there were. Therefore, when the fluorescent screen monitor having the above-described structure is used in a particle accelerator for accelerating charged particles incident at low energy to high energy, it cannot be installed at a position where the beam energy is low and must be installed at a high energy site. Did not. For this reason, the orthodox adjustment work of successively adjusting the beam control of the particle accelerator from a low energy region cannot be performed accurately, and it has to be performed by hand gesture adjustment.

[0005] The present invention has been made to solve the above problems, and prevents discharge on a fluorescent screen.
Another object of the present invention is to provide a fluorescent beam monitor capable of accurately measuring the diameter, shape and position of a beam.

[0006]

SUMMARY OF THE INVENTION A fluorescent beam monitor according to the present invention has a conductive material provided in close physical and chemical contact with a fluorescent plate and has a large number of holes formed and grounded. It is.

The size of the hole is smaller than the beam diameter.

Further, the holes are arranged in a grid pattern. Further, the width of the conductive substance connecting between the holes arranged in a lattice pattern is increased at regular intervals.

The size of a hole formed on the reference X axis and the reference Y axis of the fluorescent beam monitor is larger than the sizes of the other holes.

[0010] The size of the hole formed on the reference X axis is larger than the size of the other holes.

Further, the size of the hole formed on the reference Y axis is larger than the size of the other holes.

The thickness of the conductive material is larger than the distance at which the charged particle beam stops in the conductive material.

A conductive substance having a width smaller than the beam diameter is provided on the reference X axis and the reference Y axis.
Conductive substances other than the axis are arranged and formed in a lattice pattern.

Further, when the monitor is installed at an angle θ in the beam passage, the interval between holes inclined on the side of the beam is made larger by 1 / sin θ than the interval on the side not inclined. .

Further, in the fluorescent beam monitor according to the present invention, the fluorescent substance is provided in close contact with the conductive substance physically and chemically, arranged and formed in a number of islands, and the conductive substance is grounded. Is what is being done.

The size of the island is smaller than the beam diameter.

Further, the islands are arranged in a checkered pattern.

Further, the size of the island formed on the axis of the reference X axis and the reference Y axis of the fluorescent beam monitor is larger than the size of the other islands.

Further, the size of the island formed on the reference X axis of the fluorescent beam monitor is larger than other sizes.

The size of the island formed on the reference Y axis of the fluorescent beam monitor is larger than the size of other islands.

Further, when the monitor is installed at an angle θ in the beam passage, the interval between islands on the side inclined with respect to the beam is made larger by 1 / sin θ than the interval on the side not inclined with respect to the beam. is there.

Further, the fluorescent substance is ceramics and the conductive substance is copper, silver, gold, aluminum or an alloy thereof.

Further, a support driving mechanism is provided in the fluorescent beam monitor so that the fluorescent beam monitor can be moved in and out of the beam passage.

In the method of manufacturing a fluorescent beam monitor according to the present invention, a conductive material is deposited on a fluorescent plate by CVD, and then a number of holes are patterned by etching.

Further, after a phosphor is plated with a conductive material, a large number of holes are formed by patterning by etching.

Further, after a fluorescent substance is deposited on a conductive substance by CVD, the fluorescent substance is patterned and formed into a plurality of islands by etching.

A charged particle accelerator having a fluorescent beam monitor according to the present invention.

[0028]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 Hereinafter, a fluorescent beam monitor 10 according to a first embodiment of the present invention will be described with reference to FIG. A conductive substance 2 is provided in close physical and chemical contact with a fluorescent substance that emits fluorescence when hit by high-speed charged particles, for example, a fluorescent plate 1 made of ceramics. In this case, it is necessary that the boundary surface between the fluorescent plate 1 and the conductive substance 2 be in close contact with each other without any gap.
For example, copper as the conductive substance 2 is provided in close physical and chemical contact with the ceramic fluorescent plate 1 by vapor deposition by the D method, plating by an ion plating method, or the like. The conductive material 2 does not cover the entire surface of the fluorescent plate 1, but is provided with a large number of holes 3 without being connected to each other. The surface of the fluorescent plate 1 is exposed at the bottom surface of the hole 3. The large number of holes 3 are formed by patterning, for example, by etching or the like. Further, the conductive substance 2 is provided with a ground 4. When the fluorescent beam monitor 10 having such a structure is placed in the passage of the charged particle beam and hit by the beam, the portion of the conductive substance 2 does not emit light, and only the portion of the hole 3 emits light. Since the beam usually has a certain diameter spread in the plane, a plurality of holes corresponding to the spread portion of the beam will shine. By observing and processing this light, the performance of the accelerated beam in a charged particle accelerator or the like can be known.

The importance of the fact that the boundary between the conductive material 2 and the fluorescent screen 1 is in close contact with no gap will be described. When the energy of the charged particle beam is too low to pass through the fluorescent screen 1, electric charges are charged on the fluorescent screen 1. If conductive substance 2
If there is a gap on the contact surface between the phosphor and the fluorescent plate 1, a beam may be observed as flowing on the fluorescent plate 1 due to the influence of the discharge of the electric charge charged on the fluorescent plate 1. However, the fluorescence beam monitor 10 according to the first embodiment is
Since the conductive substance 2 and the fluorescent screen 1 are in close contact with each other without any gap, the charged charges pass through the conductive substance 2 and are grounded.
Therefore, the phenomenon that occurs in the prior art as described above does not occur. Further, the charging by the beam entering the hole 3 does not affect other holes. If the size of the hole 3 is sufficiently smaller than the diameter of the beam, the beam diameter or the beam profile can be measured with high accuracy. Further, the hole 3 shown in FIG.
Has shown a circular shape, but may be any hole shape such as a rectangle, a square and other polygons. Conductive substance 2
If the thickness is too small, the beam may pass through the conductive material 2 and reach the fluorescent screen 1, possibly causing some adverse effect. Therefore, there is no problem if the thickness is too small to allow the beam to pass.
This thickness varies depending on the type of beam (electrons or protons), energy, and conductive material, for example, 100 KeV
Electrons of energy of stop at about 40 μm in aluminum.

Embodiment 2 FIG. FIG. 2 shows a fluorescent beam monitor according to the second embodiment. The holes 3 of the conductive material 2 are arranged and formed in a grid pattern on the fluorescent plate 1. If the holes 3 are formed regularly as described above, the diameter of the beam can be directly measured without the necessity of engraving a scale on the fluorescent screen 1, which is a problem of the prior art described above. is there. Although the shape of the hole 3 is circular, it goes without saying that the shape of the hole 3 may be any shape such as a rectangle, a square, or a polygon.

Embodiment 3 FIG. 3 shows a fluorescent beam monitor having the structure of the third embodiment and a fourth embodiment described later. First, a third embodiment will be described. As can be seen from FIG. 3, holes 3a and 3 provided in the conductive substance 2 formed on the reference X-axis 8 and the reference Y-axis 9 indicating the reference position of the beam passage of the fluorescent beam monitor 10 in a grid pattern. The hole 3a is larger than the other holes 3. If the portion where the reference X axis 8 and the reference Y axis 9 intersect is set so as to coincide with the center of the beam passage 100, the displacement of the beam position can be easily measured. In other words, the position of the beam can be determined by emitting large light from the relatively large hole 3a and emitting small light from the small hole 3. The shape of the holes 3 and 3a is not limited to a circle as described in the first and second embodiments.

Embodiment 4 FIG. Next, a fourth embodiment will be described with reference to FIGS. FIG. 4 is a principle diagram when the fluorescent beam monitor 10 is actually used. The fluorescent beam monitor 10 is in a vacuum, and the camera 7 is generally installed in the atmosphere. Although the drive mechanism is not shown, it is the same as that of the conventional example shown in FIG. As shown in FIG. 4, the camera 7 is installed at right angles to the beam passage 100. Therefore, the fluorescent beam monitor 10 is provided to be inclined by θ with respect to the beam passage 100. In this case, for example, assuming that the interval between the holes 3 is d as shown in FIG. 3, the end of the beam is not at the interval d between the holes 3 when viewed from the camera 7 and appears on the beam monitor 10 at the position of d / sin θ. Such a problem does not occur in the direction perpendicular to the paper surface of FIG. Therefore, assuming that the distance between the holes 3 is d in the direction perpendicular to the plane of the paper of FIG. 4, the distance between the holes 3 in the direction inclined by θ with respect to the beam passage 100 is d / sin θ as shown in FIG. The above problem can be solved by forming at intervals of.

Embodiment 5 FIG. FIG. 5 shows a fifth embodiment. The fluorescent substance 1 is provided with a conductive substance 2 having a width 2a on the reference X-axis 8 and the reference Y-axis 9 indicating the reference position of the beam passage of the fluorescent beam monitor 10. The conductive material 2 on the fluorescent material 1 other than 9
Lattice-shaped holes 3b surrounded by a conductive material 2b having a narrower width than the width of
Grounding 4 is provided. The crossing of the reference X and Y axes of the fluorescent beam monitor 10 having such a structure is defined as a beam passage 1
If the beam center is aligned with the center of the monitor 10, if the beam center is aligned with the center of the monitor 10, it can be easily measured that the beam center does not emit fluorescent light and there is no displacement. Note that the width of the conductive material 2a on the axis of the reference X axis 8 and the reference Y axis 9 in the fifth embodiment needs to be sufficiently smaller than the beam diameter. Although not shown in the figure, if the width of the conductive material connecting the holes arranged in a lattice pattern is set to be large at certain intervals, the beam size and shape can be measured more easily.

Embodiment 6 FIG. FIG. 6 shows a sixth embodiment. The fluorescent substance 1a is provided on the conductive substance 2 in physical and chemical contact with each other, and is arranged and formed in a number of islands by patterning, for example, by etching. In this case, the boundary surface between the conductive material 2 and the fluorescent material 1a needs to be in contact with each other without any gap. For example, the ceramic 1a is physically and chemically formed on the copper plate as the conductive material 2 by vapor deposition by a CVD method. It is provided in close contact. The conductive material 2 is provided with a ground 4. Here, the size of the island-shaped fluorescent substance 1a is provided sufficiently smaller than the beam diameter. The arrangement of the island-shaped fluorescent substance 1a is determined by the fluorescent beam monitor 10 like the hole 3 shown in FIG.
May be provided at random in the plane, and if the islands are regularly arranged and formed in a grid pattern as shown in FIG. 6, the displacement of the beam can be easily measured. Further, although the circular island 1a is shown in FIG. 6, it may be rectangular, square or other polygon as shown in FIG. As shown in FIGS. 6 and 7, the fluorescent substance island 1b formed on the axis of the reference X axis 8 and the reference Y axis 9 indicating the reference position of the beam passage of the fluorescent beam monitor 10 is different from the other islands 1a. Has been enlarged. In this way, when a deviation of the beam from the reference center position occurs, the deviation can be easily observed. Further, when the fluorescent beam monitor 10 is installed at an angle of θ degrees with respect to the beam passage 100,
The distance between the islands in the tilted direction may be larger by 1 / sin θ than the distance in the non-tilted direction. In addition, the fluorescent beam monitor is provided with a supporting and driving mechanism, thereby exhibiting excellent performance on the beam path of the charged particle accelerator. This mechanism is the same as the conventional one, and will not be described.

As described above, in the structure of the fluorescent beam monitor 10 shown in the first to fifth embodiments, the conductive material having a large number of holes is arranged on the fluorescent material, and the beam passes through the holes. And hits the fluorescent substance to emit fluorescence. On the other hand, in the structure shown in Embodiment 6, a large number of fluorescent substances are arranged in an island shape on a conductive substance, and a beam directly hits this island to emit fluorescent light. There is a difference between whether there is a fluorescent substance,
The concept of preventing discharge and accurately measuring the beam characteristics is the same.

Embodiment 7 FIG. 8 is a schematic configuration diagram of an irradiation apparatus that uses a fluorescent beam monitor according to the present invention to irradiate an electron beam or X-ray for the purpose of sterilization or the like. The electron beam generated by the electron gun 50 is incident through an incidence device 51, accelerated by an acceleration cavity 52, bent by two deflection magnets 53, and returned to the acceleration cavity 52 again. After the next acceleration, since the energy has increased, the deflection magnet 53 returns with a large trajectory. As described above, the trajectory greatly expands each time the vehicle is accelerated, and finally, the trajectory protrudes from the deflecting magnet 53 and is guided to the irradiation device 54. Although not shown in FIG. 8, the entire beam passage is covered with a vacuum duct. This acceleration principle is famous as a microtron. The accelerated electron beam is expanded to an arbitrary size by the irradiation device 54, and is irradiated to a target object such as a medical device or a plant. These are continuously conveyed by the belt conveyor near the irradiation device 54, but are omitted in the figure.
When irradiating X-rays, a metal plate is installed in an irradiation device, and X-rays are generated by applying an electron beam.

When irradiating an electron beam or X-ray for the purpose of sterilizing medical instruments or plants, a high-intensity electron beam is required. For example, the energy is 5 MeV at an acceleration current of 6 mA or more.
In order to make the acceleration current 6 mA, about 12 mA or more is necessary in consideration of the fact that the current from the electron gun 50 is lost on the way. Therefore, if even a small amount of the beam hits the vacuum duct or the like when the energy is increased, the vacuum duct or the like may be melted by heat. In order to avoid this, it is necessary to accurately adjust the beam trajectory of the incident path. In FIG. 8, a fluorescent beam monitor 10 according to the present invention
The fluorescent beam monitor 10 is provided for accurately adjusting the beam trajectory, and the fluorescent beam monitor 10 on the downstream side of the acceleration cavity 52 is provided for accurately measuring the position of the first passing beam. Beam energy from the electron gun is 50 KeV
Since the energy of about 10 to about 100 KeV cannot pass through the fluorescent substance provided in the fluorescent beam monitor at such an energy, the monitor according to the present invention is effective. still,
The accelerator is not limited to the microtron type, but can be applied to any other circular or selective accelerators.

As described above, in the accelerator using the fluorescent beam monitor according to the present invention, no discharge is generated due to the charging of the electric charge, and the position of the beam can be measured accurately. It can be installed on the downstream side, and the beam performance information from the monitor
Since the beam adjustment of the accelerator can be easily and accurately performed, a large current can be accelerated, and the accelerator can be efficiently used for electron beam or X-ray irradiation. In this embodiment, the electron beam or X
Although an example of irradiation with a line has been described, the present invention is not limited to this, and it is needless to say that the invention can be widely applied to various examples of industrial use, research use, and the like using a charged particle accelerator.

[0039]

Since the present invention is configured as described above, it has the following effects.

Since a conductive substance having a large number of holes is provided in the fluorescent plate in close physical and chemical contact and is grounded,
The position and shape of the beam can be accurately measured, and the beam stopped on the surface of the fluorescent plate is guided to the ground without being charged, so that excellent beam monitoring can be performed.

Further, since many holes are smaller than the beam diameter, the position and shape of the beam can be measured more accurately.

Further, since the holes are arranged in a lattice pattern, the beam diameter can be directly measured.

The size of the hole formed on the reference X axis and the reference Y axis is larger than the size of the other holes, or the size of the hole only on the reference X axis or the size of the hole only on the reference Y axis. However, the displacement of the beam with respect to the reference position can be easily measured.

Further, since the thickness of the conductive material is greater than the distance at which the beam stops therein, the beam does not pass through the conductive material and hit the fluorescent material to contribute to light emission. Can be performed accurately.

In addition, since a conductive material having a width smaller than the beam diameter is provided on the reference X axis, the reference Y axis, or both, the displacement of the beam with respect to the reference position can be easily measured.

Further, when the monitor is installed at an angle θ with respect to the beam passage, the interval between the holes on the inclined side is larger than the interval between the holes on the non-inclined side by 1 / sin θ. The beam diameter can be measured accurately.

Further, a fluorescent substance having a large number of holes in a conductive substance is physically and chemically provided in close contact with each other and arranged and formed in a large number of islands, and the conductive substance is grounded. Beam position and shape can be measured accurately,
Beam charging can be prevented. In addition, since the amount of the conductive substance facing the beam is large, the effect of preventing static charge is great.

Since the size of the island is smaller than the beam diameter, the position and shape of the beam can be measured more accurately.

Further, since the islands are arranged and formed in a grid pattern, the beam diameter can be directly measured.

Further, since the size of an island formed on both the reference X axis and the reference Y axis, only the reference X axis, or on the reference Y axis is larger than the size of the other islands, the beam is shifted from the reference position. Can be easily measured.

Further, when the monitor is installed at an angle θ with respect to the beam passage, the interval between the islands on the inclined side is made larger by 1 / sin θ than the interval between the islands on the non-inclined side. The beam diameter can be measured accurately.

Since the conductive substance is copper, gold, silver, aluminum or an alloy thereof, the conductivity is high.
Discharge can be prevented more effectively, and proper fluorescent light is emitted because the fluorescent substance is ceramic.

Further, since the beam monitor is provided with the support driving mechanism, the beam path is not blocked during the normal operation of the accelerator.

Also, since a conductive substance is deposited or plated on the fluorescent plate by CVD, it is physically and chemically adhered, and is formed by patterning by etching. Can be manufactured.

Further, a fluorescent substance is formed on the conductive substance by CVD.
Thus, the same effect as described above can be obtained.

Further, since the fluorescent substance and the conductive substance are physically and chemically closely contacted with each other and have a fluorescent beam monitor having a large number of holes or islands formed by patterning, the charged particle accelerator is used to discharge the beam due to electric discharge or the like. Erroneous measurement, and the position and shape of the beam can be measured accurately. As a result, the operation and adjustment of the accelerator become extremely easy. It is possible to provide an excellent charged particle accelerator capable of adjusting successive devices from a low energy region instead of an operation adjustment.

[Brief description of the drawings]

FIG. 1 is a fluorescence beam monitor according to a first embodiment of the present invention.

FIG. 2 is a fluorescence beam monitor according to a second embodiment of the present invention.

FIG. 3 is a fluorescent beam monitor showing Embodiments 3 and 4 of the present invention.

FIG. 4 is a principle diagram showing a fourth embodiment of the present invention.

FIG. 5 is a fluorescence beam monitor according to a fifth embodiment of the present invention.

FIG. 6 is a fluorescence beam monitor according to a sixth embodiment of the present invention.

FIG. 7 is a fluorescence beam monitor according to a sixth embodiment of the present invention.

FIG. 8 is a schematic configuration diagram of a charged particle accelerator according to a seventh embodiment of the present invention.

FIG. 9 is a cross-sectional view of a conventional fluorescent beam monitoring device.

[Explanation of symbols]

1,1a, 1b fluorescent material, 2 conductive material, 2a, 2
b width of conductive material, 3, 3a, 3b hole, 4 ground,
6 fluorescence, 7 camera, 8 reference X axis, 9 reference Y axis,
10 Fluorescence beam monitor, 500 microtron.

Claims (23)

[Claims] 1. A fluorescent plate which is provided in a passage of a charged particle beam and is formed of a fluorescent material which emits light by irradiating the beam, and a conductive material which is provided in close physical and chemical contact with the fluorescent plate. Wherein the conductive material has a number of holes formed therein and is grounded. 2. The fluorescent beam monitor according to claim 1, wherein the size of the hole is smaller than the beam diameter. 3. The fluorescent beam monitor according to claim 2, wherein the holes are arranged in a grid pattern. 4. The fluorescent beam monitor according to claim 3, wherein the width of the conductive material connecting between the holes arranged in a lattice pattern is increased at regular intervals. 5. The method according to claim 3, wherein the size of the hole formed on the axis of the reference X axis and the reference Y axis indicating the reference position of the beam passage of the fluorescent beam monitor is larger than the size of the other holes. The fluorescent beam monitor as described. 6. The fluorescent beam monitor according to claim 3, wherein the size of the hole formed on the axis of the reference X axis of the fluorescent beam monitor is larger than the size of the other holes. 7. The fluorescent beam monitor according to claim 3, wherein the size of the hole formed on the axis of the reference Y axis of the fluorescent beam monitor is larger than the size of the other holes. 8. The fluorescent beam monitor according to claim 1, wherein a thickness of the conductive material is larger than a distance at which the charged particle beam stops in the conductive material. 9. A conductive material having a width smaller than the beam diameter is provided on the reference X axis and / or the reference Y axis indicating the reference position of the passage of the beam of the fluorescent beam monitor. 3. The fluorescent beam monitor according to claim 2, wherein the conductive substances are arranged and formed in a grid pattern. 10. When the fluorescent beam monitor is installed at an angle θ with respect to the passage of the charged particle beam, the interval between holes on the side inclined with respect to the charged particle beam is 1 / sin θ more than the interval on the side not inclined. The fluorescent beam monitor according to claim 1, wherein the size of the fluorescent beam monitor is increased. 11. A charged particle beam installed in a passage of the beam,
In a fluorescent beam monitor composed of a fluorescent substance that emits light by irradiation with the beam and a conductive substance, the fluorescent substance is physically and chemically closely attached to the conductive substance, and a large number of the fluorescent substances are provided. A fluorescent beam monitor, wherein the conductive substance is grounded. 12. The fluorescent beam monitor according to claim 11, wherein the size of the island formed of the fluorescent substance is smaller than the beam diameter. 13. The fluorescent beam monitor according to claim 12, wherein the islands are arranged and formed in a grid pattern. 14. The size of an island formed on the reference X-axis and the reference Y-axis indicating the reference position of the beam passage of the fluorescent beam monitor is larger than the size of the other islands. The fluorescent beam monitor according to 1. 15. The fluorescent beam monitor according to claim 13, wherein the size of the island formed on the axis of the reference X axis of the fluorescent beam monitor is larger than another size. 16. The fluorescent beam monitor according to claim 13, wherein the size of the island formed on the axis of the reference Y axis of the fluorescent beam monitor is larger than the size of the other islands. 17. When the fluorescent beam monitor is installed at an angle θ with respect to the charged particle beam passage, the interval of the island arrangement on the side inclined with respect to the charged particle beam is smaller than the interval on the non-inclined side by 1 /. 17. The fluorescent beam monitor according to claim 11, wherein the width is increased by sin [theta]. 18. The method according to claim 1, wherein the fluorescent substance is ceramic and the conductive substance is copper, silver, gold, aluminum or an alloy thereof.
18. The fluorescent beam monitor according to any one of 1 to 17. 19. The fluorescent beam monitor according to claim 1, wherein a support driving mechanism is provided in the fluorescent beam monitor, and the fluorescent beam monitor can be moved in and out of a beam passage. 20. The method according to claim 1, wherein a plurality of holes are formed by patterning by etching after a conductive material is deposited on the phosphor plate by CVD.
19. The method for manufacturing a fluorescent beam monitor according to 0 or 18. 21. The method for manufacturing a fluorescent beam monitor according to claim 1, wherein a large number of holes are formed by patterning by etching after a conductive material is plated on the fluorescent plate. 22. The fluorescent beam monitor according to claim 11, wherein the fluorescent material on the conductive material is formed by CVD and then patterned by etching into a plurality of islands. Production method. 23. A charged particle accelerator comprising the fluorescent beam monitor according to claim 1 to 10, 18, 19, or 19.