JPH0251900A - Tandem accelerator - Google Patents

Abstract

PURPOSE:To make an accelerating tube free from damage caused by heat generated due to a collision of beam with a canal by installing an insulator at a connection duct between a charge conversion section and an accelerating tube at a low energy side. CONSTITUTION:An insulator 11 is installed at a connection duct 2 connecting a charge conversion section 9 and an accelerating tube 1 at a low energy side. The insulator 11 is made up by forming ceramics, etc., whose thermal conductivity, for instance, is small into a circular shape, and then, installed in the middle of the connection 2. When heat is generated due to a collision of an ion with a canal 5, a part of the heat tends to advance from the connection duct 2 to the accelerating tube 1, but the connection duct 2 increases thermal gradient due to the presence of the insulator 11, so that the thermal conductivity to the accelerating tube 1 is remarkably reduced. Thereby, damage to the accelerating tube 1 caused by heat can be reduced.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a tandem accelerator.

(Prior Art) As is well known, a tandem accelerator is used for charge conversion of an ion beam, and is arranged between an acceleration tube on the low energy side and an acceleration tube on the high energy side. It is mainly composed of a charge strike 1 nopper which is a charge conversion section.

FIG. 2 shows a conventional tandem accelerator of this type.

1 is an acceleration tube on the low energy side, which is connected to a cooling plate 4 equipped with cooling fins 3 via a connecting duct 2 made of stainless steel.
It is connected to the. 5 is a canal supported by the cooling plate 4.

Reference numeral 6 denotes a duct, one end surface of which is attached to the cooling plate 4, and a canal lure is installed inside. 8 is an acceleration tube on the high energy side, which is attached to the duct 6. A charge conversion section 9 is constituted by the cooling plate 4, the canal 5.7, and the duct 6. 12 is a gas introduction pipe that supplies stripper gas to the canal lure.

The negative ion beam 10 from the acceleration tube 1 side is transmitted to the canal 5,
7 and is guided to the acceleration tube 8.

On the way, the negative ion beam 10 collides with the stripper gas in the canal and undergoes charge conversion.

The above structure and operation are already well known.

(Problem to be solved by the invention) By the way, in such a configuration, the beam is connected to the canal 5.
, 7, not all the beams pass through without loss, but depending on the beam current, accelerating voltage, and beam focusing conditions, the beams may collide with the vicinity of the center hole 5A of the canal 5 and stop. There is.

What is the kinetic energy that the beam has at this time?

converted into thermal energy. In the case of a large current tandem, this heat may exceed several hundreds of watts depending on the case.

The generated heat is conducted to the cooling plate 4 and dissipated from the fins 3 into the insulating gas, but some of the heat may be conducted to the accelerating tube 1 through the connecting duct 2.

However, as is well known, the accelerator tube 1 is made up of glass and metal electrodes, which are bonded together with adhesive, so they are susceptible to heat. You may receive significant damage.

The purpose of this invention is to prevent the accelerator tube 1 from being damaged by the heat generated when the beam collides with the canal 5.

(Means for Solving the Problems) The present invention is characterized in that a heat insulating material is provided in the connection duct that connects the charge conversion section and the low energy side acceleration tube.

(Effect) A portion of the heat generated by the beam colliding with the canal attempts to be conducted to the low-energy accelerator tube via the connecting duct, but this connecting duct is equipped with a heat insulating material. Because of this, the thermal gradient here is large, so the conduction of heat to the accelerator tube is small. This makes it possible to protect the accelerator tube from heat generated by the beam.

(Example) An embodiment of the invention will be explained with reference to FIG.

Note that parts given the same reference numerals as in FIG. 2 indicate the same or corresponding parts. According to the invention, the connecting duct 2 is provided with a heat insulating material 11. This is made of, for example, a ring-shaped material such as ceramics having low thermal conductivity, and is installed in the middle of the connecting duct 2.

The connection duct 2 and the heat insulating material 11 are preferably bonded by metal bonding to provide heat resistance.The vacuum seal connection between the acceleration tube 1 and the connection duct 2 is performed in one operation. Use a good rubber O-ring between the connecting duct 2 and the cooling plate 4.

Each vacuum seal connection between the cooling plate 4 and the duct 6 may use a heat-resistant metal gasket or metal ring.

When heat is generated due to the collision of ions with the canal 5, a part of the heat tries to go to the acceleration tube 1 through the connecting duct 2, but the thermal gradient in the connecting duct 2 becomes large due to the presence of the heat insulating material 11. Therefore, heat conduction up to the accelerator tube 1 is significantly reduced. As a result, damage to the accelerator tube 1 due to heat can be reduced.

(Effects of the Invention) As detailed above, according to the present invention, thermal damage to the accelerator tube on the low energy side due to heat generated by ions colliding with the charge conversion section is avoided as much as possible,
This brings about the effect that the safety of the accelerator tube against heat can be ensured.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an embodiment of the present invention, and FIG. 2 is a sectional view of a conventional example. l...acceleration tube on the low energy side, 2...connection duct. 3...Fin, 4...Cooling plate, 5, 7...Canal, 6.Duct, 8...High energy side acceleration tube, 1
0...Negative ion beam, 11...Insulating material, Patent applicant: Nissin High Voltage Co., Ltd. Patent attorney Kinnosuke Nakazawa

Claims (1)

[Claims] A tandem acceleration device in which a charge conversion section is arranged between a low energy side acceleration tube and a high energy side acceleration tube, and the charge conversion section is connected to the low energy side acceleration tube via a connecting duct, A tandem accelerator, wherein the connecting duct is provided with a heat insulating material so as to increase a thermal gradient between the charge conversion section and the low energy side accelerator tube.