JP2010271238A - High-speed x-ray shutter apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high-speed X-ray shutter apparatus that markedly shortens the time required, from the start of block of the X-ray until finish of block, even if the X-ray is irradiated through a comparatively large X-ray emission port. <P>SOLUTION: The apparatus has a constitution, wherein a shutter plate 231 for closing/opening the X-ray emission port 22a of an X-ray generating apparatus 21 is fixed to the tip part of a piston rod 232a of a long cylinder 232, and the piston rod 232a is in a positioned state to a retreated end in the open state of the X-ray emission port 22a, and the long cylinder is driven from the state; and after passing through a prescribed approach section, the shutter plate 231 closes the X-ray emission port 22a near an advanced end of the piston rod 232a. After the start of driving of the long cylinder 232, the speed of the piston rod 232a (shutter plate 231) is gradually accelerated from 0, and closing of the X-ray emission port 22a is initiated, when a high speed is reached, to thereby shorten the time required, from the start of closing until the finish of closing. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to an X-ray shutter device that operates at high speed.

  When evaluating afterglow characteristics of cells, precise irradiation of small experimental animals, or afterglow characteristics of X-ray luminescence devices, observe the behavior of the device after irradiating the target with X-rays and stopping the irradiation.・ It is necessary to measure.

  As a technique for stopping X-ray irradiation, there is a method of electrically stopping X-rays, that is, a method of stopping power supply to the X-ray tube, or an emission port while continuing to emit X-rays from the X-ray tube. Is closed with a shutter plate made of a material having low X-ray transmittance such as lead.

  As a shutter device that closes the emission port with a shutter plate, a method of linearly moving the shutter plate with a solenoid (see, for example, Patent Document 1) or a method of rotating (swinging) the shutter plate with a solenoid (for example, Patent Document 2). Is frequently used.

Japanese Patent Laid-Open No. 5-264795 Japanese Patent Laid-Open No. 2001-218992

  By the way, when evaluating the afterglow characteristics of cells, precise irradiation of small experimental animals, or X-ray luminescence elements, the X-ray irradiation stop operation is started from the X-ray irradiation state of the object. Therefore, the time required until the stop is completed (actually, an X-ray dose of 1/100 or less of the irradiation state) is an important factor. That is, in this kind of evaluation, since the behavior of the object after the X-ray is stopped is investigated, for example, the time required from when the X-ray emission opening is closed until the fully closed state is reached. If it becomes longer, it is not clear which time point is the X-ray stop time point, and only a part of the object is irradiated with X-rays from the start of closing until the fully closed state is reached. Therefore, it becomes difficult to evaluate that portion. For this reason, the time required from the start of the X-ray irradiation stop operation to the stop completion state is required to be as short as possible, and it is desirable that the stop is completed within a few ms from the start of the X-ray irradiation stop. .

  The conventional method of electrically stopping X-ray irradiation requires 500 ms or more from when the stop is started until the stop is completed (until the X-ray dose becomes 1/100 or less). Further, in the conventional method of moving or rotating the shutter plate with a solenoid, when the X-ray emission port is small and a small and light shutter plate is used, the time required to complete the X-ray blocking can be shortened. However, if the X-ray exit port is relatively large, for example, about 10 mm, it may take several 100 ms from the start of driving the shutter plate to shut off the X-rays until the shut-off is completed.

  The present invention has been made in view of such circumstances, and even if X-rays are irradiated through a relatively large X-ray emission port, the time required from the start of the X-ray blocking to the completion of the blocking. It is an object of the present invention to provide a high-speed X-ray shutter device that can significantly reduce the length of the device compared to conventional devices.

  In order to solve the above-described problems, a high-speed X-ray shutter device according to the present invention is a high-speed X-ray shutter device that opens and closes an X-ray exit port of an X-ray generator, and closes / opens the X-ray exit port. And a long cylinder that linearly moves the shutter plate to perform an opening / closing operation. The shutter plate is fixed to a tip end of a piston rod of the long cylinder, and the X-ray emission port is opened. Then, the piston rod is located at the retracted end, and after driving the long cylinder from that state through a predetermined running section, the shutter plate closes the X-ray exit near the forward end of the piston rod. It is characterized by being comprised (claim 1).

  Here, in the present invention, the long cylinder has a region in which the cushion mechanism operates before the piston rod reaches the forward end, and the shutter plate is moved immediately before reaching the operation region of the cushion mechanism. It is desirable that the X-ray emission port is configured to be in a fully closed state (claim 2).

  In the present invention, the shutter plate is guided in the width direction at one end in the width direction orthogonal to the moving direction of the long cylinder and in the plate thickness direction at the other end. ) Can be suitably employed.

  Here, in the present invention, the long cylinder refers to a stroke that is several times or more, more preferably several tens or more times the required stroke, in comparison with a stroke that simply needs to open and close the X-ray exit port by the shutter plate. Say the cylinder you have. The working fluid may be air or hydraulic oil, but it is desirable to use a pneumatic cylinder from the viewpoint of not requiring a large operating force and simplifying the apparatus.

  In the present invention, the actuator for driving the shutter plate is a long cylinder, the shutter plate is fixed to the tip of the piston rod of the long cylinder, and the shutter plate closes the X-ray exit near the forward end of the piston rod. With this configuration, the problem is to be solved.

  That is, the piston rod of the cylinder has an initial speed of driving, that is, an initial speed of 0, and is gradually accelerated by continuing the driving. Since the shutter plate for blocking the X-ray exit with a relatively large aperture is made of a material that does not allow X-rays to pass through, the cylinder is driven to close the X-ray exit. Even so, the initial driving speed is slow. Therefore, in the present invention, the shutter plate is fixed to the tip of the piston rod of the long cylinder, and after passing through a predetermined running section, the X-ray emission port is closed near the forward end of the piston rod. As a result, the shutter plate starts closing the X-ray exit port while being accelerated at a high speed, and the time required from the start of closing the X-ray exit port to the completion of closing, and accordingly, the object is irradiated with X-rays. The time required from the stop to the completion of the stop is shortened, and is particularly effective for precise irradiation of cells, precise irradiation of small experimental animals, and investigation of fluorescence characteristics such as X-ray luminescence elements.

  Further, it is essential to provide a cushion mechanism at the stroke end of a cylinder that is driven at a high speed. However, as in the invention according to claim 2, immediately before reaching the operating region of the cushion mechanism, X By configuring the line exit to be in the fully closed state, it is possible to perform the closing operation of the X-ray exit at the position where the operating speed of the long cylinder is the fastest.

  Further, as in the invention according to claim 3, by adopting a configuration in which one end in the width direction orthogonal to the moving direction of the shutter plate is guided in the width direction and the other end is guided in the plate thickness direction, the long cylinder Even if the shutter plate is moved at a high speed and with a long stroke using this, there will be no problems such as twisting.

  According to the present invention, even when X-rays are irradiated through a relatively large X-ray emission port, the time required from completion of X-ray blocking to completion can be significantly shortened compared to the conventional case. In particular, precise irradiation of cells, precise irradiation of small experimental animals, and evaluation of fluorescence characteristics of an X-ray luminescence element can be performed accurately.

It is a front longitudinal cross-sectional view of embodiment of this invention. It is AA sectional drawing of FIG. It is the C section enlarged view of FIG. FIG. 4 is an enlarged view taken along line DD in FIG. 3. It is EE sectional drawing of FIG. It is FF sectional drawing of FIG. It is GG expanded sectional drawing of FIG.

DESCRIPTION OF SYMBOLS 1 Protective box 11 Bracket 2 X-ray generator 21 X-ray tube 22 Collimator 22a Opening 23 Shutter device 231 Shutter plate 232 Pneumatic cylinder (long cylinder)
232a Piston rod 233 Linear motion guide 233a Guide rail 233b Slider 234 Guide groove 234a Guide body 3 Shelf 4a, 4b Photoelectric switch

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1 and 2 are views showing the overall configuration of the main part of the embodiment of the present invention. FIG. 1 is a front longitudinal sectional view, FIG. 2 is an AA sectional view, and FIG. 2 corresponds to a BB cross-sectional view in FIG.

  An X-ray generator 2 is arranged inside the protective box 1. The X-ray generator 2 mainly includes an X-ray tube 21 and emits X-rays vertically downward through a collimator 22 disposed below the X-ray tube 21. Further, the opening of the collimator 22 which is the X-ray emission port can be opened and closed by the shutter plate 231 by driving a shutter device 23 which will be described in detail later. The material of the shutter plate 231 is not particularly limited. If the dose is 1/100 from the X-ray dose in the X-ray irradiation state, there is no need to use lead. can do.

  A shelf 3 whose upper and lower positions can be arbitrarily changed is arranged vertically below the X-ray generator 2, and an evaluation object (not shown) is arranged on the shelf 3. For example, in evaluating the afterglow characteristics of the X-ray luminescence element, the X-ray tube 21 is driven in a state in which an object to be evaluated is placed on the shelf 3 and the opening of the collimator 22 is closed by the shutter plate 231. When the tube voltage / tube current reaches the specified value, the shutter plate 231 is automatically driven to open the opening of the collimator 22, and the object is irradiated with X-rays. The opening of the collimator 22 is closed by the plate 231. The object for which the X-ray irradiation has been completed is subjected to measurement of the residual light quantity by a detector (not shown).

  Now, as described above, the shutter device 23 opens and closes the opening of the collimator 22 and linearly moves the shutter plate 231 in the direction indicated by the arrow in FIG. A long pneumatic cylinder 232 as an actuator, a linear guide 233 that guides the shutter plate 231 in the width direction (direction orthogonal to the paper surface in FIG. 2), and a guide groove 234 that similarly guides the shutter plate 231 in the plate thickness direction. Is the main constituent. The pneumatic cylinder 232 is supported by the bracket 11 that protrudes horizontally from the protection box 1.

  3 is an enlarged view of a portion C in FIG. 2, FIG. 4 is an enlarged view of DD in FIG. 3, FIG. 5 is a sectional view taken along line EE in FIG. 4, and FIG. FIG. 7 is a cross-sectional view, and FIG. 7 is an enlarged cross-sectional view taken along line GG in FIG. 3. The shutter device 23 will be described in detail below with reference to these drawings. The shutter plate 231 is attached to the tip of the piston rod 232 a of the pneumatic cylinder 232. The pneumatic cylinder 23b is significantly longer than the stroke required to open and close the opening 22a of the collimator 22 by the shutter plate 23a. The opening 22a of the collimator 22 is a 10 mm square, whereas the pneumatic cylinder 23b The stroke is 1000 mm.

  The shutter plate 231 is guided in two directions orthogonal to the moving direction by driving the pneumatic cylinder 232. That is, as shown in FIGS. 3 and 7, a guide rail 233a of the linear motion guide 233 is laid along the moving direction of the shutter plate 231, and a slider 233b sliding on the guide rail 233a is provided as a shutter plate. It is fixed to the back surface on one end side in the width direction of 231 (direction orthogonal to the moving direction and orthogonal to the plate thickness direction). The other end in the width direction of the shutter plate 231 is inserted into a guide groove 234 formed in a guide body 234a laid along the moving direction of the shutter plate 231 with a predetermined gap. Thereby, even if the shutter plate 231 moves at a high speed and a relatively long distance, the occurrence of twisting and the like can be suppressed.

  Photosensors 4a and 4b are respectively arranged on both sides of the opening 22a of the collimator 22 on the moving stroke of the shutter plate 231, and when the shutter plate 231 passes through these arrangement positions, that is, the opening 22a. A signal to that effect is output at the closing start time and closing completion time.

  The pneumatic cylinder 232 described above is provided with a cushion mechanism, and the piston rod 232a extends from the front end of the piston rod 232a by 200 mm before the forward end, that is, the piston rod 232a extends by 800 mm from the rear end (extension amount 0 mm). The cushion mechanism operates from this position. When the pneumatic cylinder 232 is driven to advance the piston rod 232a, the shutter plate 231 fully closes the opening 22a of the collimator 22 immediately before the piston rod 232a enters the operation area of the forward end cushion mechanism.

  That is, the cushion plate 231 has a length in the moving direction of about 220 mm (as will be apparent from the following description, this length needs to be 210 mm or more, with a margin of about 10 mm). The closing of the opening 22a of the collimator 22 is started from the position where the piston rod 232a of the pneumatic cylinder 232 extends by about 780 mm, and when the extending amount of the piston rod 232a reaches about 790 mm, the opening 22a of the collimator 22 is fully closed. Then, when the vehicle further advances about 10 mm, it is decelerated by the cushion mechanism and eventually reaches the forward end. During this time, the shutter plate 231 maintains the fully closed state of the opening 22a of the collimator 22.

  Therefore, when an X-ray stop command is generated, the piston rod 232a starts moving forward from the initial speed of 0 and accelerates, and the 780mm until just before entering the operation region of the cushion mechanism at the forward end is set as a running section, which is almost the maximum speed. When reaching the position, the closing operation of the opening 22a of the collimator 22 is executed. As a result, the time required for the opening 22a of the collimator 22 from the closing start to the closing completion, that is, the time required from the X-ray irradiation state to the stopping completion can be shortened as compared with the prior art. As a result, the time required to fully close the 10 mm opening 22a could be 3 ms or less.

  The high-speed X-ray shutter of the present invention is actually shut off after starting X-ray blocking, such as precision irradiation to cells, precision irradiation to small experimental animals, evaluation of afterglow characteristics of X-ray luminescence elements, etc. For example, an X-ray afterglow characteristic evaluation apparatus can be used to increase the X-ray blocking speed and perform an accurate evaluation of afterglow characteristics.

Claims (3)

A high-speed X-ray shutter device that opens and closes an X-ray exit of an X-ray generator,
A shutter plate for closing / opening the X-ray emission port; and a long cylinder for linearly moving the shutter plate to perform an opening / closing operation. The shutter plate is disposed at a piston rod tip of the long cylinder. When the X-ray exit opening is fixed, the piston rod is positioned at the retracted end, and the long cylinder is driven from that state to pass through a predetermined running section. A high-speed X-ray shutter device, wherein a shutter plate is configured to close the X-ray emission port.   The long cylinder has a region where the cushion mechanism operates before the piston rod reaches the forward end, and the shutter plate fully closes the X-ray emission port immediately before reaching the operation region of the cushion mechanism. The high-speed X-ray shutter device according to claim 1, wherein the high-speed X-ray shutter device is configured to be in a state.   The shutter plate is guided in the width direction at one end in the width direction orthogonal to the moving direction of the long cylinder, and in the plate thickness direction at the other end, respectively. High-speed X-ray shutter device.

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