JPH0693399B2 - Variable-inductance quadrupole particle accelerator and high-frequency resonator used therefor - Google Patents

Description

The present invention relates to a variable-inductance quadrupole particle accelerator and a high-frequency resonator used for the same, and in particular, a high-frequency resonance circuit is provided outside an accelerating tube, and The present invention relates to a variable-inductance quadrupole particle accelerator suitable for variable frequency for adjusting final acceleration energy, and a high-frequency resonator used therefor.

[Conventional technology]

As a conventional example of a frequency tunable quadrupole particle accelerator in which a high frequency resonance circuit is provided outside the accelerating tube and the resonance frequency of the resonance circuit is made variable, there is one as disclosed in JP-A-60-115199. is there.

An example of the structure of a conventional frequency tunable quadrupole particle accelerator is shown in FIG. In the figure, reference numeral 1 denotes a vacuum vessel which is an accelerating tube. In the vacuum vessel 1, a vacuum vessel 1 is introduced into a central portion surrounded by quadrupole electrodes 2a, 2b, 2c and 2d having a wavy shape in the axial direction The heavy pole electrodes 2a, 2b, 2c, 2d are housed. The ion beam is accelerated by a high-voltage electric field formed by the quadrupole electrodes 2a, 2b, 2c, 2d. Ions are sequentially accelerated as they progress in the axial direction, and low-energy incident ions (usually tens of keV in energy) become high-energy ions (usually in the order of MeV) and are finally ejected. The length of the quadrupole electrodes 2a, 2b, 2c, 2d is on the order of several tens of cm to several meters.

The resonance circuit for generating a high frequency high voltage in FIG. 2 is composed of a one-turn coil 4 and a variable capacitance capacitor 5 arranged outside the vacuum container 1. Reference numeral 3 in the drawing denotes an inductive coupling coil for transmitting the electric power from the high frequency power source 6 to the resonance circuit. Then, the resonance frequency is changed by changing the capacitance of the variable capacitance capacitor 5 of the resonance circuit, and by making this frequency variable, the final acceleration energy can be freely adjusted for any ion species.

[Problems to be Solved by the Invention]

To explain the characteristics of the electric circuit composed of the one-turn coil 4 and the variable capacitance capacitor 5 shown in FIG. 2, its basic circuit configuration is shown in FIG.

In FIG. 3, the output voltage of the high frequency power source 6 is as small as several kV, but a high frequency high voltage of several tens to several hundreds kV can be generated in the resonance circuit by interposing the resonance circuit. This high voltage can be generated only at a specific frequency determined by the resonance frequency. Therefore, in order to generate a high voltage at any frequency, it is necessary to continuously change the resonance frequency of the circuit by some method.

The resonance frequency f ₀ of the series resonance circuit shown in FIG. 3 is given by the equation (1).

Therefore, to change the resonance frequency f ₀ , the inductance L,
Either or both of the capacitor capacities C may be changed. In the conventional example shown in FIG. 2, a method of changing the capacitor capacity is adopted. This is because it is necessary to change the diameter and the number of turns of the coil 4 in order to change the inductance L of the coil 4, and it is generally difficult to design a specific structure.

On the other hand, in the circuit configuration diagram shown in FIG. 3, the high frequency voltage Vf generated across the variable capacitance capacitor 5 is given by the equation (2).

Here, Pw is the electric power of the high frequency power source 6, and r is the electric resistance (for example, the resistance of the coil 4) of the resonance circuit.

As a method of combining the values of the inductance L and the capacitor capacitance C that give the same resonance frequency f ₀ from the equations (1) and (2),
It can be seen that if a combination with a large L value is selected, the generated high frequency voltage Vf becomes higher. Therefore less high frequency power Pw
The high-frequency voltage Vf can be efficiently generated by using, and the power load of the high-frequency power source 6 is reduced, and the size can be reduced.

From the above, if a specific structural example in which the number of turns and the like can be varied within a range where the L value is large is realized, a high frequency high voltage can always be efficiently generated when the resonance frequency f ₀ changes.

Usually, the value L of the inductance of the coil 4 having the radius a, the number of turns N, and the length 1 is given by the equation (3).

Here, K is a constant (Nagaoka coefficient) determined by the ratio of the radius a and the length l, and μ ₀ is the magnetic permeability in vacuum. To change the inductance L value of the coil 4 continuously, the radius a of the coil 4,
The number N of turns and the length l may be changed.

FIG. 4 shows a conventional resonator structure that is the basis of a resonator including a resonance circuit that changes the L value of the coil 4. In Figure 4
A multi-turn coil 4'is fixedly mounted in a metallic resonator container 7 filled with SF ₆ or the like. In the region shown by the base portion 10 of the resonator container 7 in the figure, the capacitance formed between the linear portion of the coil 4'and the resonator container 7 and the inductance of the multi-turn coil 4 ' The resonance frequency f ₀ is determined by the value (L value). Electric power from the high frequency power supply 6 is supplied into the resonator container 7 through the capacitive coupling coupler 8.

The resonator structure of FIG. 4 generally has a resonance frequency in the region of several MHz to several tens of MHz, so if an improvement that can change the number of turns in the coil 4'is added, it will be used as a variable frequency quadrupole particle accelerator. It becomes possible to use.

However, with the structure of the resonator container 7 shown in FIG. 4 as it is, the coil itself is rotated to move in the axial direction and a part of the coil 4 ′ is taken out of the resonator container 7, whereby the resonator container 7 is removed. The number of coil turns and length cannot be changed.

The present invention has been made in view of the above points, and an object thereof is to change the number of turns of a coil arranged in a resonator container with a simple configuration and within a range of a large value of inductance. Accordingly, it is an object of the present invention to provide an inductance variable quadrupole particle accelerator and a high frequency resonator used for the same, which can always efficiently generate a high frequency voltage when the resonance frequency changes.

[Means for Solving the Problems]

The present invention has two pairs of electrodes arranged facing each other around the axis through which charged particles pass, corrugates the surfaces of the electrodes in the axial direction, and faces the surfaces of the electrodes facing each other. The waves formed by are the same, and the wave formed by the surface of the adjacent electrode is 180
° Quadrupole electrodes configured to be out of phase, a vacuum container accommodating the quadrupole electrodes, and a high frequency wave arranged outside the vacuum container and supplying a high frequency voltage to the two sets of electrodes. The high-frequency resonator includes a resonator, and the high-frequency resonator is configured by providing a multi-winding coil in a resonator container. The high-frequency resonator is electrically operated by an inductance of the coil and a capacitance formed between the resonator container and the coil. Characteristic LC series resonance circuit is configured, and the inductance value is made variable by mechanically adjusting the number of coil turns in the resonator container.

Specifically, in the high-frequency resonator, the coil itself is rotated and linearly moved to make the number of turns of the coil in the resonator container variable, or the high-frequency resonator has the resonator container in which one end of the coil is in contact. Rotate and move the lid of
The number of coil turns in the resonator container is variable.

Further, in addition to the above configuration, the high-frequency resonator has another cylindrical multiple-type capacitor mounted in the resonator container, and simultaneously changes the capacitance value of the capacitor in accordance with the rotation and rectilinear movement of the coil itself.

Further, the resonator container of the high-frequency resonator has a substantially cylindrical shape, and one end of the cylinder has a disk having a bottom surface of the cylinder divided into two semicircular plates, and the semicircular plates are opened in the axial direction of the cylinder. A high frequency resonator used for an inductance variable quadrupole accelerator in which the open portion is closed by a triangular plate member and the triangular plate member has a hole through which a coil passes Is characterized by.

[Action]

With the configuration of the present invention, the coil itself is rotated and moved linearly, or the lid of the resonator container in contact with one end of the coil is rotated and moved linearly, so that the number of coil turns in the resonator container is mechanically increased. Since the inductance value can be made variable with a simple configuration that is simply adjusted to, the above object is achieved.

〔Example〕

Hereinafter, the present invention will be described in detail based on the illustrated embodiments. The same reference numerals are used for the same reference numerals.

FIG. 1 shows an embodiment of the present invention. The configuration of this embodiment shown in the figure is substantially the same as the conventional configuration. In this embodiment, while rotating the coil itself, the coil is moved in the axial direction, a part of the coil is taken out of the resonator container, and the lid part is provided to mechanically change the number of turns and the length of the coil in the resonator container. It is improving.

As shown in Fig. 1, the end surface of the coil 4'exposed to the outside of the resonator container 7 has a shape in which a triangular lid 7'and semi-circular lids 7 ", 7 are joined together. The shape-shaped lids 7 ″ and 7 have a structure in which the originally circular-shaped lid is divided into semicircles, the two pieces are tilted back and forth, and the open portion is closed by the triangular-shaped lid 7 ′. Furthermore, the triangular lid 7 '
Has a small hole through which the coil 4'exists outside the resonator container 7.

In Fig. 1, as shown in Fig. 1A, the lids 7 "and 7 are attached with the same inclination as that of the coil 4'of multiple turns. Therefore, the coil 4'of multiple turns is rotated. Then, the coil 4 ′ can smoothly go out of the resonator container 7 without hitting the lid.
The rotation of the coil 4 '(rotation about the central axis) may be performed manually, or a special rotating device may be used for the coil 4'.
You may attach it to. As a result, a practical L variable quadrupole particle accelerator can be realized by using a resonator that realizes variable frequency by changing the number of turns and the length of the coil 4'having a plurality of turns. When actually used in a quadrupole particle accelerator, two resonators according to FIG. 1 are provided, and the voltage generated by each resonator is quadrupled according to the feeding method to the quadrupole electrodes shown in FIG. It will be supplied to the polar electrodes.

Next, the effect of the embodiment of the present invention will be described.

The structure for confirming the effect is that the coil 4'is made of copper, the number of turns is 4 to 5 turns, and the diameter of the wire is 10 mm or more in order to reduce the resistance value. The radius of coil 4'is
It is 10 cm to 20 cm, and the coil length is 30 to 50 cm. The resonator container 7 has a diameter of 60 cm to 80 cm, and the inner surface thereof is plated with copper having a thickness of 15 μm or more to reduce the resistance value of the resonator. In the case of such a structure, the coil 4'is rotated to rotate the resonator container 7
When the number of turns inside was changed, the resonance frequency changed continuously in the range of 5MHz to 30MHz. When the power from the high frequency power source 6 is supplied to this through the capacitive coupling type coupler 8,
High-frequency high voltage of ± 60kv or more could be easily generated for input power of several kW to 35kW. By the way, in the conventional example (variable C type) shown in FIG. 2, it was difficult to generate a high frequency high voltage of ± 60 kv or more unless input power of 100 kW or more was supplied.

When a high frequency voltage according to this example was supplied to a corrugated quadrupole electrode having a length of 1 to 2 m to accelerate the ion beam, B ⁺ , P
Ions such as ⁺ and As ⁺ are 0.5 to 4 from the incident energy of several 10 keV.
Accelerated above MeV. Further, when the frequency of the high frequency voltage is changed by changing the number of turns and the length of the coil 4'in the resonator container 7 for the acceleration of a specific ion species, the acceleration energy freely changes in proportion to the square of the frequency. did it.

Next, another embodiment according to the present invention is shown in FIG. Fifth
In the drawing, a female screw 7a is cut on the resonator container 7, a lid is a male screw lid 7b, and a coil 4'of a plurality of turns is fixed. Here, the number of coils wound and the length in the resonator container 7 were changed by rotating the male screw lid 7b. In this case, the female screw
The pitch of the screws of 7a and the male screw lid 7b is selected to be the same as the coil pitch of the coil 4'having a plurality of turns. In the case of the embodiment shown in FIG. 5, the characteristics similar to those of the embodiment using FIG. 1 were obtained and the frequency was variable. The first
In the embodiment shown in FIG. 5 and FIG.
A gas such as SF ₆ above atmospheric pressure is enclosed to prevent electrical insulation.

Next, another embodiment based on the present invention is shown in FIG. Sixth
In the embodiment shown in the drawing, a condenser 9 in which a plurality of cylinders are engaged with each other is provided in the base portion of the resonator container 7. This is aimed at giving another effect described below.

According to the principle diagram shown in FIG. 1, when the L value is changed,
The impedance Zs of the resonator viewed from the high frequency power source 6 side changes according to the equation (4).

In order to efficiently supply the power from the high-frequency power source 6 to the resonator without reflecting it, it is necessary to match the impedance Zs with the output impedance of the power source (normally 50Ω or 75Ω constant). In order to realize variable frequency, the resonator container 7
When the L value of the coil 4'inside is changed, the impedance Zs of the formula (4) also changes. To prevent such impedance mismatch, the C value may be changed in the same manner as the L value is changed. In the multi-cylinder capacitor 9 shown in FIG. 6, when the number of coil turns in the resonator container 7 decreases, the distance between the two cylinders increases and the C value decreases.

In the embodiment using the resonator having the configuration shown in FIG. 6, the size of the capacitor 9 is selected so that the impedance Zs becomes 75Ω. The capacitance of the capacitor changed in the range of 300 to 1200 pF with the change of the L value of the coil 4 '. When high frequency power was applied to such a resonator, the reflected power returning to the power supply was stably maintained at 10% or less for a variable frequency range of 5 to 30 MΩ, and the impedance Zs was kept constant as the L value was varied. I found out. Therefore, the output of the high frequency power supply 6 is stable, and the power supply operation is significantly simplified.

When the L-variable quadrupole particle accelerator of this embodiment is used as described above, a high frequency high voltage can be efficiently generated in accordance with the frequency variation, so that the power load of the high frequency power source is small, and therefore the power source size and the like are small. Therefore, the entire device becomes smaller. Furthermore, since the structure that can change the capacitor capacity is added, the load impedance can be kept constant and the power supply operates stably.
Therefore, it has a remarkable effect on the stable operation of the accelerator.

〔The invention's effect〕

According to the variable-inductance quadrupole particle accelerator and the high-frequency resonator used for the same of the present invention described above, two pairs of electrodes arranged facing each other around the axis through which charged particles pass are provided. The surfaces of the electrodes are corrugated in the axial direction, and the waves of the surfaces of the electrodes facing each other of the electrodes are equal, and the waves of the surfaces of the adjacent electrodes are 180 ° out of phase with each other. A quadrupole electrode, a vacuum container accommodating the quadrupole electrode, and a high-frequency resonator arranged outside the vacuum container and supplying a high-frequency voltage to the two sets of electrodes. Is configured by providing a coil in the resonator container, and an electrical LC series resonance circuit is configured by the inductance of the coil and the capacitance formed between the resonator container and the coil, and The number of coil turns in the resonator container Quadrupole particle accelerator with variable inductance whose inductance value is variable by adjusting
And the resonator container of the high-frequency resonator has a substantially cylindrical shape, and one end of the cylinder has a cylinder bottom circular plate divided into two semicircular plates, and the semicircular plates are opened in the axial direction of the cylinder, It is a high frequency resonator used for an inductance variable quadrupole particle accelerator in which the open part is closed by a triangular plate member, and the triangular plate member has a hole through which a coil passes. Therefore, the number of turns of the coil placed in the resonator container can be changed with a simple configuration and in the range of large inductance value, so that high frequency voltage can be generated efficiently and efficiently when the resonance frequency changes. A variable inductance quadrupole particle accelerator and a high-frequency resonator used therefor can be obtained.

[Brief description of drawings]

FIG. 1 (A) is a sectional view showing an embodiment of a resonator used in the variable inductance quadrupole particle accelerator of the present invention.
FIG. 2B is a perspective view thereof, FIG. 2 is a configuration diagram illustrating a conventional frequency tunable quadrupole particle accelerator with variable capacity, and FIG.
The figure is a circuit diagram for explaining the configuration as an equivalent circuit of FIG.
FIG. 4 is a sectional view showing a conventional resonator structure including a multi-turn coil, FIG. 5 is a sectional view showing another embodiment of the present invention, and FIG. 6 is a sectional view showing yet another embodiment of the present invention. It is a figure. 1 ... vacuum container, 2a, 2b, 2c, 2d ... corrugated quadrupole electrode,
3 ... Inductive coupling coil, 4 ... One-turn coil, 5 ...
… Variable capacitance condenser, 6 …… High frequency power source, 7 …… Resonator container, 7d …… Lid, 7 ′ …… Triangular lid, 7 ″, 7…
... Semi-circular lid, 8 ... Capacitive coupling type coupler, 9 ... Multiple cylindrical condenser.

Front Page Continuation (72) Kensuke Amamiya Kensuke Amamiya 1-280 Higashi Koigokubo, Kokubunji, Tokyo Metropolitan Research Laboratory Hitachi, Ltd. Central Research Laboratory Kiyozumi Yazawa (56) Reference JP-A-63-193500 (JP, A)

Claims (6)

[Claims] 1. A pair of electrodes arranged facing each other around a shaft through which charged particles pass, the surface of the electrodes being corrugated in the axial direction, and the electrodes facing each other. The waves formed by the surfaces of are the same, and the waves formed by the surfaces of the adjacent electrodes are
A quadrupole electrode configured to be 180 ° out of phase, a vacuum container that houses the quadrupole electrode, and a high frequency voltage that is arranged outside the vacuum container and is applied to the two sets of electrodes. A quadrupole particle accelerator including a high-frequency resonator and accelerating charged particles with a high-voltage electric field formed by the quadrupole electrode, wherein the high-frequency resonator includes a multi-winding coil provided in a resonator container. The coil has an inductance and an electrostatic capacitance formed between the resonator container and the coil to form an electrical LC series resonance circuit, and the number of coil turns in the resonator container is mechanically adjusted. A variable-inductance quadrupole particle accelerator characterized by adjusting the inductance value. 2. The variable-inductance quadrupole particle according to claim 1, wherein the high-frequency resonator is configured such that the coil itself is rotated and moved linearly to change the number of coil turns in the resonator container. Accelerator. 3. The high-frequency resonator rotates and rectilinearly moves a lid of the resonator container, which is in contact with one end of the coil,
The quadrupole particle accelerator with variable inductance according to claim 1, wherein the number of coil turns in the resonator container is variable. 4. The high-frequency resonator is characterized in that another cylindrical multiple-type capacitor is installed in the resonator container, and the capacitance value of the capacitor is simultaneously changed with the rotation and rectilinear motion of the coil itself. The variable inductance quadrupole particle accelerator according to claim 1. 5. A gas for preventing electrical insulation is sealed in the resonator container.
4. A variable-inductance quadrupole particle accelerator according to any one of the above. 6. An electrode having two pairs of electrodes arranged facing each other around a shaft through which charged particles pass, corrugating the surface of the electrode in the axial direction, and facing each other among the electrodes. The waves formed by the surfaces of are the same, and the waves formed by the surfaces of the adjacent electrodes are
A high frequency resonator which is arranged outside a vacuum container accommodating a quadrupole electrode configured to be 180 ° out of phase and supplies a high frequency voltage to the two sets of electrodes. The container has a substantially cylindrical shape, and at one end of the cylinder, a disk having a bottom surface of the cylinder is divided into two semi-circular plates, the semi-circular plate is opened in the axial direction of the cylinder, and the opened part is formed into a triangular plate shape. A high-frequency resonator used in a variable-inductance quadruple particle accelerator, which has a structure in which a member is closed, and a hole through which a coil passes is provided in the triangular plate-shaped member.