JP2001033557A - Ionization box with tension structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To miniaturize and stabilize an ionization space capacity, improve the position measurement of radiation beams, and perform accurate measurement by providing a step or a groove on a mounting surface for mounting an electrode film. SOLUTION: A step for applying tension to an electrode film 1 is provided between an electrode latch surface 6 and a mounting surface for mounting the electrode film 1, and the electrode film 1 is pinched and fixed by a space ring 3 by a mounting ring 2. A tension ring 4 that presses the electrode film 1 from the above to the electrode latch surface 6 and has a push-out projection for applying tension to the electrode film 1 is fixed to the recessed part of the space ring 3, or a groove may be provided instead of the step. With the configuration, specific, designed tension can be applied to the electrode film 1 and an ionization layer space that is stable for a long time can be maintained. Further, by providing the step within a range for preventing the ionization film 1 from causing permanent distortion, the same tension can be applied to the ionization film 1 even in the case of repeated reassembly.

Description

DETAILED DESCRIPTION OF THE INVENTION

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of an ionization chamber in radiation measurement.

2. Description of the Related Art When an electrode film is put on an ionization chamber,
An electrode film that is larger than the range used as the electrode film is made, and tension is evenly applied to the outer periphery of the electrode film, and then attached to the ionization chamber in that state. The sticking method is a method of sandwiching and fixing between an ionization chamber and a mounting ring.

Problems to be Solved by the Invention The measurement of the radiation beam position and the dose by the ionization chamber requires miniaturization of the ionization space and minimization of the fluctuation of the ionization space capacity by improving the connected circuit system. In the case of the conventional structure, it is difficult to set the tension of the electrode film, and during long-term use, the electrode film is loosened, the distance between the electrodes is changed, and the ionization space capacity is changed. In reassembly after removing the electrode film, it was necessary to assemble again by applying an external tension.

Means for Solving the Problems In order to provide a step for applying tension to the electrode film, between an electrode stopping surface for accurately setting an electrode film surface constituting an ionization space and a mounting surface for mounting the electrode film. Place the flat electrode film on the created space ring with the mounting ring and fix it in place.From above, press the electrode film against the electrode stop surface and apply a tension ring with an extrusion protrusion that gives tension to the electrode film, the space ring Structure to be fixed according to the concave shape of
Alternatively, the groove may be formed by the O-ring instead of the step ring, instead of the step. The ionization film can be made as thin as possible by using an attachment ring as a base and forming an integrated structure. The problem is solved by combining these features.

[Action] A predetermined ring designed by inserting a tension ring or a space ring having a cylindrical extrusion protrusion into an electrode membrane fixed to an electrode membrane support having an electrode stop surface up to the electrode stop surface. Can be applied to the electrode film, and a stable ionospheric space can be maintained for a long period of time. Further, if a step is provided in a range where the ionized film does not cause permanent distortion, the same tension can be applied to the ionized film even during several reassembly. The electrode having a monolithic structure can make the interval between the electrodes extremely small while applying tension, can also increase the assembly position accuracy in the direction of the electrode film, and can improve the position resolution of the radiation beam.

Embodiment An embodiment will be described with reference to the drawings. FIG. 1 shows an embodiment, in which an electrode film, a mounting ring,
Consists of a space ring, tension ring, electrode stop surface, mounting surface, other internal shield, cover, and mounting base. The electrode film is centered on the space ring and fixed with the mounting ring. The tension ring is pushed from above the fixed electrode film to the electrode stop surface, and the electrode film is stretched with a predetermined tension. FIG. 2 shows an embodiment of an electrode having an integral structure in which the electrode film and the substrate are integrated, and is composed of the electrode film and the substrate.
A base is attached to the outer periphery of the electrode film to form an integrated electrode. The monolithic electrode is used instead of the mounting ring and the electrode membrane.

Since the present invention is configured as described above, it is effective in miniaturizing and stabilizing the ionization space capacity, increasing the resolution of the position measurement of the radiation beam, minimizing the fluctuation of the dose measurement, Exact measurement can be expected.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view for realizing claim 1;

FIG. 2 is a development view and a cross-sectional view for realizing claim 2;

[Explanation of symbols]

 ] Electrode membrane Mounting ring Space ring Tension ring Base Electrode retaining surface Mounting surface

Claims (2)

[Claims] In an ionization chamber for radiation measurement, as a method for keeping electrodes parallel to each other against a force due to a pressure difference between the inside and the outside, an attractive force between electrodes, and a reaction force, a step for mounting an electrode film and a step relative to the mounting surface are provided. For an electrode membrane stretched and fixed on an electrode membrane support with an electrode stop surface with a hole, a tension ring or space ring with a cylindrical extrusion protrusion is inserted along the step and fixed to the electrode stop surface An ionization chamber with a tension structure that has a structure that applies a predetermined tension to the electrode membrane or a structure that inserts into the groove instead of a step 2. In the ionization chamber for radiation measurement, when mounting the electrode film, a rigid base is provided on the outer periphery of the electrode film, and an integrated electrode integrally formed with the electrode film, a space ring and a tension ring, etc. Composed,
Ionization chamber with tension structure