JP2017084574A - Untuned high-frequency acceleration cavity, accelerator, and impedance adjustment method of untuned high-frequency acceleration cavity - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide: an untuned high-frequency acceleration cavity, simplifying an installation operation of a magnetic body core, and also capable of improving flexibility of selection of a magnetic body core; an accelerator; and an impedance adjustment method of an untuned high-frequency acceleration cavity.SOLUTION: An untuned high-frequency acceleration cavity includes: a first vacuum duct 11 with conductivity through the inside of which charged particles pass; a second vacuum duct 12 with insulation properties at the inside of which an electric field accelerating charged particles is generated; an inner conductor 13 connected vertically to the first vacuum duct 11 at one end thereof; an annular magnetic body core 14 surrounding the inner conductor 13; and a housing 15 with conductivity surrounding the first and second vacuum ducts 11, 12, the inner conductor 13, and the magnetic body core 14.SELECTED DRAWING: Figure 1

Description

  Embodiments according to the present invention relate to an untuned radio frequency acceleration cavity, an accelerator, and an impedance adjustment method for an untuned radio frequency acceleration cavity.

  The non-tuned high-frequency acceleration cavity includes a disk-shaped magnetic core, a metal duct that penetrates the center of the magnetic core, that is, an inner conductor, a ceramic duct having an acceleration gap, and these magnetic core, metal duct, and ceramic duct. A surrounding housing, that is, an outer conductor is provided. The non-tuned radio frequency acceleration cavity having such a configuration accelerates a beam, that is, a charged particle, with a radio frequency electric field generated in an acceleration gap. Unlike tuned high-frequency acceleration cavities that control the resonant frequency in response to fluctuations in the input high-frequency by applying a bias current to the magnetic core, untuned high-frequency acceleration with a magnetic core that has high-frequency characteristics over a wide bandwidth In the cavity, a mechanism for applying a bias current is omitted. For this reason, the non-tuned high frequency acceleration cavity can simplify the high frequency acceleration system more than the tuning high frequency acceleration cavity.

  However, in the conventional non-tuned high-frequency accelerating cavity, the magnetic core is arranged on the beam line. For this reason, when exchanging the magnetic core, it is necessary to break the vacuum in the duct and then replace the magnetic core, and to re-exhaust the duct after replacing the magnetic core. Therefore, the conventional non-tuned high frequency acceleration cavity has a problem that it is difficult to install the magnetic core. In addition, the conventional non-tuned high-frequency accelerating cavity is subject to spatial restrictions by other equipment adjacent on the beam line. Therefore, the conventional non-tuned high-frequency accelerating cavity has a problem that it is difficult to improve the degree of freedom in selecting the magnetic cores such as the number and thickness of the magnetic cores.

Japanese Patent No. 3054712

  The present invention has been made to solve the above-described problems, and is a non-tunable high-frequency acceleration cavity capable of simplifying the installation work of the magnetic core and improving the degree of freedom in selecting the magnetic core. An object of the present invention is to provide a method for adjusting an accelerator and a non-tuned high-frequency acceleration cavity.

The untuned high-frequency acceleration cavity according to this embodiment is
A conductive first vacuum duct through which charged particles pass;
An insulating second vacuum duct in which an electric field for accelerating the charged particles is generated;
An inner conductor connected perpendicularly to the first vacuum duct at one end;
An annular magnetic core surrounding the inner conductor;
A conductive case surrounding the first and second vacuum ducts, the inner conductor, and the magnetic core;

The accelerator according to this embodiment is
An accelerator with a non-tuned high frequency accelerating cavity,
The non-tuned high frequency acceleration cavity is
A conductive first vacuum duct through which charged particles pass;
An insulating second vacuum duct in which an electric field for accelerating the charged particles is generated;
An inner conductor connected perpendicularly to the first vacuum duct at one end;
An annular magnetic core surrounding the inner conductor;
A conductive case surrounding the first and second vacuum ducts, the inner conductor, and the magnetic core;

The impedance adjustment method of the non-tuned high frequency acceleration cavity according to the present embodiment is
A method for adjusting the impedance of a non-tuned high-frequency acceleration cavity,
A conductive first vacuum duct through which charged particles pass;
An insulating second vacuum duct in which an electric field for accelerating the charged particles is generated;
An inner conductor connected perpendicularly to the first vacuum duct at one end;
An annular magnetic core surrounding the inner conductor;
Adjusting the outer diameter of the inner conductor in a non-tunable high-frequency accelerating cavity including the first and second vacuum ducts, the inner conductor, and a conductive casing surrounding the magnetic core. Including.

  ADVANTAGE OF THE INVENTION According to this invention, the installation operation | work of a magnetic body core can be simplified, and the freedom degree of selection of a magnetic body core can be improved.

FIG. 1A is a cross-sectional view of a non-tuned high-frequency accelerating cavity showing the first embodiment, and FIG. 1B is a cross-sectional view of the magnetic core cut along the IB-IB cross section of FIG. 1A. It is sectional drawing of the magnetic body core which shows 2nd Embodiment. It is sectional drawing of the untuned high frequency acceleration cavity which shows 3rd Embodiment. It is sectional drawing of the untuned high frequency acceleration cavity which shows 4th Embodiment. FIG. 5A is a cross-sectional view showing an acceleration cavity before adjustment in the method of adjusting the impedance of an untuned high-frequency acceleration cavity according to the fifth embodiment, and FIG. 5B is a cross-sectional view showing the acceleration cavity after the increase in impedance. FIG. 5C is a cross-sectional view showing the acceleration cavity after impedance reduction. FIG. 6A is a cross-sectional view illustrating an acceleration cavity before adjustment in an impedance adjustment method for a non-tuned high-frequency acceleration cavity according to a sixth embodiment, and FIG. 6B is a cross-section illustrating an acceleration cavity after an increase in impedance. FIG. 6C is a cross-sectional view showing the acceleration cavity after impedance reduction.

  Embodiments according to the present invention will be described below with reference to the drawings. This embodiment does not limit the present invention.

(First embodiment)
First, as a first embodiment, a non-tuned high-frequency acceleration cavity including one inner conductor and a magnetic core that is continuous in the circumferential direction will be described. FIG. 1A is a cross-sectional view of an untuned high-frequency acceleration cavity 1 showing the first embodiment. 1B is a cross-sectional view of the magnetic core 14 taken along the line IB-IB in FIG. 1A.

  The untuned high-frequency acceleration cavity 1 of the first embodiment can be used for a circular accelerator such as a synchrotron accelerator. As shown in FIG. 1A, the non-tuned high-frequency acceleration cavity 1 of the first embodiment includes a first vacuum duct 11, a second vacuum duct 12, an inner conductor 13, a magnetic core 14, and a casing 15. That is, an outer conductor is provided. A high frequency power source 2 is connected between the first vacuum duct 11 and the housing 15.

  The first vacuum duct 11 has a cylindrical shape along the beam line, that is, the beam axis 10. The first vacuum duct 11 is made of metal so as to have conductivity. Charged particles, that is, a beam, pass through the first vacuum duct 11 along the beam axis 10 in a vacuum state.

  The second vacuum duct 12 is connected to one end of the first vacuum duct 11 and has a cylindrical shape along the beam line. The second vacuum duct 12 has an acceleration gap 121 inside. Moreover, the 2nd vacuum duct 12 is formed with the ceramic so that it may have insulation. By applying high-frequency power from the high-frequency power source 2 between the first vacuum duct 11 and the housing 15, a high-frequency acceleration electric field is generated in the acceleration gap 121. The charged particles passing through the first vacuum duct 11 are accelerated by the acceleration electric field.

  The inner conductor 13 is connected perpendicularly to the first vacuum duct 11 at one end thereof. More specifically, the inner conductor 13 is detachably connected to the first vacuum duct 11 by a fixing member such as a flange or a screw (not shown). In FIG. 1A, the inner conductor 13 is a cylindrical metal duct (that is, a metal pipe) extending in a direction perpendicular to the beam line. However, a metal rod may be adopted as the inner conductor 13 instead of the metal duct. Good.

  A plurality of the magnetic cores 14 are arranged along the extending direction of the inner conductor 13 so as to surround the outer peripheral surface of the inner conductor 13. As shown in FIG. 1B, the magnetic core 14 has an annular shape that is continuous in the circumferential direction. By applying high-frequency power from the high-frequency power source 2 between the first vacuum duct 11 and the housing 15, a current flows through the inner conductor 13 so as to penetrate the magnetic core 14. This current induces a magnetic field in the direction around the outer peripheral surface of the inner conductor 13 inside the magnetic core 14, and an acceleration electric field is formed in the acceleration gap 121. Further, by providing the magnetic core 14 having a high magnetic permeability, the optical path length is increased and the length of the inner conductor 13 is suppressed.

  The housing 15 surrounds the first vacuum duct 11, the second vacuum duct 12, the inner conductor 13, and the magnetic core 14. The casing 15 is made of metal so as to have conductivity. The housing 15 is grounded.

  The first vacuum duct 11 and the second vacuum duct 12 include accelerators other than the asynchronous high-frequency accelerating cavity 1 such as other vacuum ducts 3 and electromagnets 4 (for example, quadrupole electromagnets and deflection electromagnets) on the beam line. The components are connected.

  In the untuned high-frequency accelerating cavity 1 of the first embodiment having the above configuration, the magnetic core 14 is installed on the outer periphery of the inner conductor 13 that deviates from the beam line. Thereby, the magnetic core 14 can be easily installed without breaking the vacuum state in the first vacuum duct 11. Further, since the magnetic core 14 is installed on the outer periphery of the inner conductor 13, the magnetic core 14 is not subjected to spatial restrictions by other devices adjacent on the beam line. Thereby, compared with the case where a magnetic body core is installed on a beam line, the number and thickness of the magnetic body core 14 can be selected freely. In addition, since the untuned high-frequency accelerating cavity 1 can be transported without penetrating the second vacuum duct 12 through the magnetic core 14, the risk of breakage of the ceramic second vacuum duct 12 can be reduced.

  Therefore, according to the first embodiment, the installation work of the magnetic core 14 can be simplified, the degree of freedom of selection of the magnetic core 14 can be improved, and the second vacuum duct can be improved. 12 breakage can be suppressed.

(Second Embodiment)
Next, as a second embodiment, a non-tuned high-frequency acceleration cavity 1 in which a magnetic core 14 is divided in the circumferential direction will be described. In the second embodiment, the same reference numerals are used for the components corresponding to the above-described embodiments, and redundant description is omitted. FIG. 2 is a cross-sectional view of the magnetic core 14 showing the second embodiment. FIG. 2 is a cross-sectional view corresponding to FIG. 1B.

  As shown in FIG. 2, the magnetic core 14 of the second embodiment is equally divided into two core portions 141 and 142 in the circumferential direction. The number of divisions of the magnetic core 14 is not limited to two. For example, the magnetic core 14 may be divided into three or more core portions.

  According to the untuned high-frequency acceleration cavity 1 of the second embodiment, the magnetic resistance of the magnetic core 14 can be adjusted by adjusting the gap between the core portions 141 and 142. Thereby, the Q value, which is the ratio of the half width to the resonance frequency, can be easily set to a desired value.

(Third embodiment)
Next, as a third embodiment, a non-tuned high-frequency accelerating cavity 1 including a plurality of inner conductors 13 having a symmetric positional relationship with respect to the second vacuum duct 12 will be described. In the third embodiment, the same reference numerals are used for the components corresponding to the above-described embodiments, and a duplicate description is omitted. FIG. 3 is a cross-sectional view of the non-tuned high-frequency accelerating cavity 1 showing the third embodiment.

  As shown in FIG. 3, the non-tuned high-frequency accelerating cavity 1 of the third embodiment includes two inner conductors 13 having a point-symmetrical positional relationship with respect to the symmetry point p on the second vacuum duct 12. . Each inner conductor 13 is connected to two first vacuum ducts 11 arranged so as to sandwich the second vacuum duct 12 in the beam line direction. A plurality of magnetic cores 14 are arranged on the outer periphery of each inner conductor 13.

  In the third embodiment, two high-frequency power sources 2 are provided so as to correspond to the two first vacuum ducts 11. Instead of providing two high-frequency power sources 2, the high-frequency power of one high-frequency power source 2 may be distributed to two by a distributor.

  Note that the two inner conductors 13 may be arranged so as to have a mirror image symmetrical positional relationship with respect to the second vacuum duct 12, but when the space in the beam line direction is suppressed, the point symmetrical positional relationship is set. It is preferable to arrange each inner conductor 13 so as to have it.

According to the non-tuned high-frequency accelerating cavity 1 of the third embodiment, by applying high-frequency powers having opposite phases to each first vacuum duct 11, the square of the high-frequency voltage V compared to the first embodiment. The value of the shunt impedance V ² / 2P divided by 2 times the power loss P can be doubled. Thereby, it is possible to obtain an acceleration voltage higher than that of the first embodiment.

(Fourth embodiment)
Next, as a fourth embodiment, a non-tuned high-frequency accelerating cavity 1 including an exhaust device will be described. In the fourth embodiment, the same reference numerals are used for the components corresponding to the above-described embodiments, and a duplicate description is omitted. FIG. 4 is a cross-sectional view of the non-tuned high-frequency accelerating cavity 1 showing the fourth embodiment. In FIG. 4, the high-frequency power supply 2 is not shown.

  As shown in FIG. 4, the non-tuned high-frequency accelerating cavity 1 of the fourth embodiment has an exhaust device on the other end side of the inner conductor 13 opposite to one end of the inner conductor 13 connected to the first vacuum duct 11. 17. Further, the inside of the inner conductor 13 communicates with the inside of the accelerator duct including the first vacuum duct 11. The exhaust device 17 exhausts the inside of the accelerator duct through the inner conductor 13.

  According to the untuned high-frequency accelerating cavity 1 of the fourth embodiment, the exhaust device 17 is installed at the end of the inner conductor 13 that deviates from the beam line, compared with the case where the exhaust device is installed on the beam line. The space on the beam line can be used effectively.

  When a plurality of inner conductors 13 are provided as shown in the third embodiment, a plurality of exhaust devices 17 may be provided so as to correspond to the respective inner conductors 13.

(Fifth embodiment)
Next, as a fifth embodiment, an impedance adjustment method for an untuned high-frequency acceleration cavity based on the outer diameter of the inner conductor will be described. In the fifth embodiment, the same reference numerals are used for the components corresponding to the above-described embodiments, and a duplicate description is omitted. FIG. 5A is a cross-sectional view showing the untuned high-frequency acceleration cavity 1 before impedance adjustment in the impedance adjustment method for the untuned high-frequency acceleration cavity 1 according to the fifth embodiment. FIG. 5B is a cross-sectional view showing the untuned high-frequency accelerating cavity 1 after increasing the impedance. FIG. 5C is a cross-sectional view showing the untuned high-frequency accelerating cavity 1 after impedance reduction.

  By arranging the inner conductor 13 at a position deviating from the beam line, in the untuned high-frequency accelerating cavity 1, the inner conductor 13 can be easily changed, so that the inner conductor 13 and the magnetic core 14 can be changed. The interval can be adjusted easily. Since the distance between the inner conductor 13 and the magnetic core 14 can be easily adjusted, the impedance of the untuned high-frequency accelerating cavity 1 can be easily adjusted. For example, as shown in FIG. 5B, the impedance can be easily increased by changing (replacing) the inner conductor 13 of the non-tuned high-frequency accelerating cavity 1 of FIG. 5A to the inner conductor 13 having a larger outer diameter. . Conversely, as shown in FIG. 5C, the impedance can be easily reduced by changing the inner conductor 13 of the non-tuned high-frequency accelerating cavity 1 of FIG. 5A to the inner conductor 13 having a smaller outer diameter. When a metal bar is used as the inner conductor 13, the outer diameter of the inner conductor 13 may be reduced by processing the metal bar.

  According to the fifth embodiment, the impedance of the non-tuned high-frequency accelerating cavity 1 can be easily adjusted according to the desired performance.

(Sixth embodiment)
Next, as a sixth embodiment, an impedance adjustment method for an untuned high-frequency acceleration cavity based on the outer diameter of the inner conductor and the inner diameter of the magnetic core will be described. In the sixth embodiment, the same reference numerals are used for the components corresponding to the above-described embodiments, and a duplicate description is omitted. FIG. 6A is a cross-sectional view showing the non-tuned high-frequency acceleration cavity 1 before impedance adjustment in the impedance adjustment method of the non-tuned high-frequency acceleration cavity 1 according to the sixth embodiment. FIG. 6B is a cross-sectional view showing the untuned high-frequency accelerating cavity 1 after the impedance is increased. FIG. 6C is a cross-sectional view showing the untuned high-frequency accelerating cavity 1 after impedance reduction.

  In the sixth embodiment, for example, as shown in FIG. 6B, the inner conductor 13 in FIG. 6A is changed to an inner conductor 13 having a larger outer diameter, and the magnetic core 14 in FIG. Also, the impedance can be easily increased by changing to the magnetic core 14 having a small inner diameter. Conversely, as shown in FIG. 6C, the inner conductor 13 in FIG. 6A is changed to an inner conductor 13 having a smaller outer diameter, and the magnetic core 14 in FIG. 6A is replaced with a magnetic core having a larger inner diameter. By changing to 14, the impedance can be easily reduced.

  Also in the sixth embodiment, as in the fifth embodiment, the impedance of the non-tuned high-frequency accelerating cavity 1 can be easily adjusted according to the desired performance.

  The impedance may be adjusted by changing the inner diameter of the magnetic core 14 while keeping the outer diameter of the inner conductor 13 constant.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 1 Asynchronous high frequency acceleration cavity 11 1st vacuum duct 12 2nd vacuum duct 13 Inner conductor 14 Magnetic body core 15 Case

Claims (9)

A conductive first vacuum duct through which charged particles pass;
An insulating second vacuum duct in which an electric field for accelerating the charged particles is generated;
An inner conductor connected perpendicularly to the first vacuum duct at one end;
An annular magnetic core surrounding the inner conductor;
A non-tunable high-frequency accelerating cavity comprising: the first and second vacuum ducts; a conductive casing surrounding the inner conductor and the magnetic core;   The non-tuned high-frequency acceleration cavity according to claim 1, wherein the magnetic core is divided into a plurality of parts in the circumferential direction.   The non-tuned high-frequency acceleration cavity according to claim 1 or 2, wherein the inner conductor is a metal duct.   The untuned high-frequency acceleration cavity according to claim 1 or 2, wherein the inner conductor is a metal rod.   5. The non-tuned high-frequency accelerating cavity according to claim 1, wherein a plurality of the inner conductors are arranged so as to have a symmetrical positional relationship with respect to the second vacuum duct. The inside of the inner conductor communicates with the inside of the first vacuum duct,
The non-tuned high-frequency acceleration cavity according to claim 3, wherein the non-tuned high-frequency acceleration cavity includes an exhaust device disposed on the other end side of the inner conductor. An accelerator with a non-tuned high frequency accelerating cavity,
The non-tuned high frequency acceleration cavity is
A conductive first vacuum duct through which charged particles pass;
An insulating second vacuum duct in which an electric field for accelerating the charged particles is generated;
An inner conductor connected perpendicularly to the first vacuum duct at one end;
An annular magnetic core surrounding the inner conductor;
An accelerator comprising the first and second vacuum ducts, the inner conductor, and a conductive casing surrounding the magnetic core. A method for adjusting the impedance of a non-tuned high-frequency acceleration cavity,
A conductive first vacuum duct through which charged particles pass;
An insulating second vacuum duct in which an electric field for accelerating the charged particles is generated;
An inner conductor connected perpendicularly to the first vacuum duct at one end;
An annular magnetic core surrounding the inner conductor;
Adjusting the outer diameter of the inner conductor in a non-tunable high-frequency accelerating cavity including the first and second vacuum ducts, the inner conductor, and a conductive casing surrounding the magnetic core. Impedance adjustment method including.   The impedance adjustment method according to claim 8, comprising adjusting an inner diameter of the magnetic core.