JPH075300U - Tandem accelerator equipped with ion source - Google Patents

Abstract

(57) [Summary] [Purpose] To construct an ion source with the same structure as stripper canal so that the ion source can be operated without opening the pressure tank. [Structure] The PIG ion source 11 is arranged between the stripper canal 6 and the high energy side acceleration tube 7, and has cathode electrodes 12 and 13, an anode electrode 14, and a cathode electrode 13.
And an extraction electrode 16 that is integrally coupled with The cathode electrode and the extraction electrode are configured as movable electrodes that are guided and positioned by the guide members 17 and 18, and the positioning shaft 20 is used to perform positioning operation from outside the terminal duct 5. During operation of the ion source, the extracted ions are accelerated by the high energy side acceleration tube. During tandem acceleration, the cathode and extraction electrodes retreat to a position where they do not block the passage of the beam from the stripper canal due to the operating axis.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a tandem accelerator having an ion source having a coaxial structure with a stripper canal.

[0002]

[Prior art]

 As shown in FIG. 2, the tandem accelerator is housed in a pressure tank 1, and negative ions from a negative ion source are introduced into the low energy side acceleration tube 2. A high voltage is applied to the accelerating tube from a high-voltage power supply 3 via a high-voltage terminal unit 4, and the ion beam is initially accelerated. The accelerated negative ion beam is provided in the terminal duct 5, and is converted into a positive ion beam by the stripper canal 6 into which the stripper gas for charge conversion is introduced, and the same beam is accelerated on the high energy side acceleration tube. It accelerates again toward the ground potential at 7. Therefore, tandem acceleration cannot be performed or a sufficient acceleration beam cannot be obtained for ion species such as negative ions that cannot be generated or that can be obtained only in trace amounts, such as nitrogen and helium. Therefore, for ion species that are difficult to generate negative ions or can generate only a small amount, a positive ion source is installed in the tandem accelerator to obtain the desired acceleration beam under the single-stage acceleration method using a high-energy accelerating tube. There is.

FIG. 3 shows an example of the stripper canal (6) of the charge conversion section provided in the terminal duct 5 between the low energy side acceleration tube 2 and the high energy side acceleration tube 7. ) Was removed and the positive ion source 8 was directly attached to the high energy side acceleration tube 7. However, since the tandem accelerator is configured so that each component is housed in the pressure tank (1) filled with the high-pressure insulating gas in order to apply a high voltage to the accelerating tube, the positive ion source 8 should be installed. Requires breaking the vacuum in the beam path, recovering the insulating gas, replacing the inside of the tank with the atmosphere, opening the pressure tank, and removing the stripper canal, which requires a lot of labor and time.

Therefore, there has been proposed a device in which the ion beam from the positive ion source can be accelerated without changing the components in the tandem accelerator. FIG. 4 is a configuration diagram of a tandem accelerator in which a positive ion source is installed in the high-voltage terminal portion so as to be deviated from the axis of the accelerating tube. The positive ion source 8 is located on the side of the stripper canal 6 which is the charge conversion section in the terminal duct 5 in the high voltage terminal section, and is installed deviated from the axis of the high energy side acceleration tube 7. Has been done. The canal 9 that guides the beam from the positive ion source 8 merges with the stripper canal 5 at the downstream portion thereof, and the end of the confluence channel is open at the entrance front of the high-energy side accelerating tube 7, and the stripper canal 6 and canal 9 A bending electromagnet 10 is provided at the joint flow path portion of the above.

During normal tandem acceleration, the negative ion beam from the low energy side accelerating tube 2 undergoes charge conversion in the stripper canal 6 to which the stripper gas is supplied, and is accelerated in the high energy side accelerating tube 7. . At the time of accelerating an ion species where it is difficult to generate negative ions, the positive ion source 8 is operated, the positive ion beam is deflected by the magnetic field of the deflection electromagnet 10 and introduced into the high energy side acceleration tube 7, and accelerated.

According to such a tandem accelerator, many positive and negative ion species can be accelerated without recomposing the constituent elements, but the positive ion source 8 interferes with the stripper canal 6. A large space is inevitably required for mounting in a place where it does not occur, and further, a device for bending the positive ion beam such as the deflection electromagnet 10 is required.

[0007]

[Problems to be solved by the device]

 An object of the present invention is to provide a tandem accelerator capable of operating an ion source without opening a pressure tank by configuring an ion source in the stripper canal installation portion with a coaxial structure with the stripper canal. It is a thing.

[0008]

[Means for Solving the Problems]

 The present invention relates to a tandem accelerator equipped with an ion source, which is provided with an ion source having a coaxial structure with the stripper canal in the stripper canal portion, and the ion source has a movable electrode arranged at the coaxial position with the stripper canal. It is characterized by being configured as.

[0009]

[Action]

 For ion species for which it is difficult to generate negative ions, positive ions are extracted from the ion source and accelerated by the high energy side accelerating tube. During tandem acceleration, the movable electrode of the ion source is withdrawn from the coaxial position with the stripper canal, and positive ions from the canal are introduced into the high energy side acceleration tube.

[0010]

【Example】

 An embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a configuration diagram of a tandem accelerator in which a stripper canal is provided with a PIG type ion source, and the same reference numerals as those in FIGS. 2 to 4 indicate the same parts. The PIG type ion source 11 is formed between the stripper canal 6 and the high energy side acceleration tube 7 in a coaxial structure with the canal part. The same ion source is provided between the cathode electrodes 12 and 13, and the both cathode electrodes, and the anode electrode 14 coaxial with the stripper canal 6 and the extraction electrode sandwiching the insulator 15 and integrally connected to the cathode electrode 13 are provided. Have 16.

The cathode electrode 12, the cathode electrode 13, and the extraction electrode 16 are configured as movable electrodes that are guided and positioned by the guide members 17 and 18, and these movable electrodes that are arranged at the same coaxial position as the stripper canal 6 are provided. Is positioned and operated from outside the duct by an operating shaft 20 penetrating the terminal duct 5 via a connecting member 19. Each of the guide members 17 and 18 has a circular opening coaxial with the stripper canal 6 at the center. An ion source chamber 21 is provided between the guide members 17 and 18, and the cylindrical anode electrode 14 is attached to the ion source chamber via an insulator 22. Necessary for PIG discharge around the chamber. A coil 23 for generating a strong magnetic field is provided. The ion source gas into the ion source chamber is supplied from a passage 24 provided in the cathode electrode 12 through a passage formed in a connecting member 19 which communicates with the operation shaft 20 as a hollow shaft.

The cathode electrodes 12 and 13 are grounded at a high voltage at the same potential as the high voltage terminal portion, and the anode electrode 14 is grounded at a high voltage by a changeover switch 25 or higher than a ground potential at a high voltage by a DC power supply 26. The extraction electrode 16 is biased to the same potential as the second-stage accelerating electrode of the high energy side accelerating tube 7, and a beam extraction potential lower than that of the cathode electrode 13 is applied.

When performing normal tandem acceleration in the tandem accelerator, the cathode electrode 12 and the cathode electrode 13 and the extraction electrode 16 block the beam passage from the stripper canal 6 by operating the operating shaft 20 in the arrow direction. You will be relocated to a safe position. The anode electrode 14 is grounded at a high voltage by the switch 25 and functions as a part of stripper canal.

When the PIG ion source 11 is operated, the cathode electrode 12 and the cathode electrode 13 and the extraction electrode 16 are at the positions shown in the drawing, and the anode electrode 14 is given a potential higher than the high voltage ground potential by the DC power supply 26. Ion source gas is supplied from the hollow operation shaft 20 into the ion source chamber 21, PIG discharge is performed between the cathode electrodes 12 and 13 and the anode electrode 14, and positive ions are extracted by the extraction electrode 16, resulting in high energy acceleration. Introduced into tube 2.

[0015]

[Effect of device]

 Since the present invention is configured as described above, the structure of the stripper canal and the structure of the ion source are compatible with each other, and the ion source can be operated without opening the pressure tank. It is possible to reduce the space for mounting the ion source.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an embodiment of the present invention.

FIG. 2 is a principle configuration diagram of a tandem accelerator.

FIG. 3 is a configuration diagram of a conventional example in which a positive ion source is attached to a high energy side acceleration tube.

FIG. 4 is a configuration diagram of another conventional example.

[Explanation of symbols]

 5 Terminal duct 6 Stripper canal 7 High energy side acceleration tube 11 PIG ion source 12 Cathode electrode 13 Cathode electrode 14 Anode electrode 16 Extraction electrode 20 Operation axis

Claims (1)

[Scope of utility model registration request] 1. A stripper canal part is provided with an ion source having a coaxial structure with the stripper canal, and the ion source has a movable electrode arranged at a coaxial position with the stripper canal. A tandem accelerator equipped with a characteristic ion source.