JP2591493Y2 - Dosimeter with cover - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dose equivalent meter for measuring a dose equivalent as an indicator of the effect of radiation on the human body.

[0002]

2. Description of the Related Art In recent years, facilities such as nuclear facilities, hospitals, universities and research laboratories handling isotopes have increased, and various radiological devices such as X-ray apparatuses have been frequently used for diagnosing or treating diseases. Radiation control is more important than ever.

[0003] The effect of radiation on the human body is indicated by the so-called "dose equivalent", and in Japan, the allowable dose equivalent is legally defined by the Radiation Hazard Prevention Law.

[0004] From the above, measurement of dose equivalent is extremely important for those who handle radiation, and conventionally, dose equivalent has been measured using, for example, an ionization chamber (for example, see Japanese Unexamined Patent Publication No. No. 304851).

[0005]

However, the effect of radiation on the human body varies depending on the tissue or the depth from the body surface.
In some aspects, measurement of the m-dose equivalent alone is not enough.

Against this background, the above-mentioned Radiation Hazard Protection Law has been revised. In this revision, the dose equivalent of 70 μm and 3 mm must be measured in addition to the dose equivalent of 1 cm. I have. On the other hand,
Even before such revision of the law, measuring various dose equivalents is extremely significant for radiation protection.

However, in a conventional dose equivalent meter, 1
There has been a demand for a dose equivalent meter that only measures cm dose equivalents and that can be easily measured with the same dose equivalent in accordance with the revised law or other dose equivalents.

[0008] The 1 cm, 3 mm, 70 mm
μm indicates a dose equivalent converted from an absorbed dose at each depth of a so-called ICRU sphere simulating a human body.

The present invention has been made in view of the above-mentioned conventional problems, and an object of the present invention is to provide a dose equivalent meter that can easily measure various dose equivalents with a single dosimeter. is there.

[0010]

To achieve the above object of the Invention The present invention includes a detection unit for detecting radiation, and attenuation cover cormorants covering the detection portion is detachably attached to the detection unit, It is characterized by including .

[0011] The present invention, in the covered dose equivalent meter of claim 1 wherein the presence or absence of the mounting of the attenuation cover 及
Identification hand <br/> stage identifies the type of the attenuation cover during mounting of the prime mover, characterized in that it comprises a, a calculation section that performs calculation of dose equivalent in accordance with the identification result of the identifying means.

[0012]

According to the above construction, an attenuating cover which is detachably attached to the detection unit for detecting ordinary radiation is prepared. First, a dose equivalent at a certain depth is set without attaching the cover. When the measurement is performed and the dose equivalent at a depth deeper than the depth is measured, the attenuation cover is attached to the detection unit and the dose equivalent is measured. Therefore, the dose equivalent can be measured at a plurality of depths depending on whether or not the cover is attached. In this case, if means for identifying the presence or absence of the cover and the type of the cover when the cover is provided is provided, it is possible to automatically convert and correct the measurement result into the dose equivalent.

Therefore, according to the present invention, when the attenuating cover is not mounted, for example, a 70 μm dose equivalent can be measured, and by attaching the first attenuating cover, a 3 mm dose equivalent can be measured. By attaching the second attenuation cover, the 1 cm dose equivalent can be measured. Of course, it is also possible to freely measure the dose equivalent at a depth not defined by law by changing the thickness of the cover.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an external view of a dose equivalent meter with a cover according to the present invention, wherein (A) is a front view,
(B) is a right side view.

This dose equivalent meter with a cover is roughly divided into
The ionization chamber 10 shown in FIG. 1 and the measuring unit 1 shown in FIG.
The ionization chamber 10 will be described first.

The ionization chamber 10 is composed of a base section 14 containing a measuring circuit and a detection section 16 in which air or the like is sealed. A collecting electrode 18 for collecting charges generated by the incidence of radiation is disposed inside the detecting unit 16. In the present embodiment, the case 20 of the detection unit 16 is
It is made of an equivalent material of a living tissue (for example, ABS resin), and has a thickness of, for example, 1 mm. here,
A conductive resin coating 22 is provided on the inner surface of the case 20.
Is applied, and a high voltage is applied between the collector electrode 18 and the resin coating 22 thereof to form an ionization chamber. Detector 1
A sensitivity adjusting plate 24 made of a metal plate or the like is joined and arranged inside 6, so that the energy dependency is improved. This adjusting plate is, for example, as disclosed in
No. 851 can be applied.

The base 14 is provided with a handle 14a, and the ionization chamber 10 is gripped by grasping the handle, or mounted on a tripod or the like by a separately provided mounting portion. In this embodiment, three metal fittings 26 for attaching a cover described later are provided on the base portion 14. A projection 28 for positioning the cover projects from the surface of the base 14 on the side of the detection unit 16.

The ionization chamber 10 of the present embodiment has a substantially cylindrical shape, as is apparent from FIG. 2B, a cross-sectional area of about 100 cm ² and a volume of about 2 liters. Here, the length of the detection unit 16 is about 20 cm, and its thickness is about 1 to 2 mm. In the present embodiment, a dose equivalent of 70 μm is measured by the ionization chamber 10 shown in FIG. In this case, since the sensitivity adjusting plate 24 is provided, the dose equivalent can be measured with high accuracy and without energy dependency.

FIG. 2 shows the appearance of a 3 mm dose equivalent measurement cover 30 as a first cover, and FIG.
Is a front view, and (A) is a left side view. As shown in the figure, the cover 30 is made of a tissue equivalent material, and has a cylindrical hollow inside.

The cover 30 is provided with the above-mentioned metal fitting 2.
A hook 32 that engages with the hook 6 is provided. When the cover 30 is attached to the detection unit 16 shown in FIG. 1, the metal fitting 26 is hooked and fixed to the hook 32. When the cover 30 is attached, the detecting unit 1
6. There is almost no gap between the case 20 and the cover 30. Here, the thickness of the cover 30 is, for example, 5 mm, and the thickness of the cylindrical body and the thickness of the disk-shaped front plate may be changed.

As shown in FIG. 2 (A), a magnet 34 is disposed at the edge of the cover 30 on the mounting side to the ionization chamber 10. When the cover 30 is mounted on the ionization chamber 10, the magnet 34 By detecting the magnetism of the cover 34 with the magnetic sensor 36 shown in FIG. 1, the type of the cover can be determined. The pair of magnets 36 in FIG. 1 are arranged on one side and the other side of the base portion 14. This is to distinguish the 3 mm dose equivalent measurement cover 30 shown in FIG. 2 from the 1 cm dose equivalent measurement cover 40 described below.

FIG. 3 shows the appearance of a 1 cm dose equivalent measurement cover 40 as the cover of FIG.
Is a front view, and (A) is a left side view. As is clear from comparison with the cover 30 shown in FIG. 2, the cover 40 has a large thickness, for example, 12 mm.
Of thickness. Of course, the thickness of the side surface and the thickness of the front surface may be changed.

The cover 40 is made of a tissue equivalent material, and is provided with a hook 42. The hook 42 is engaged with the metal fitting 26 when the cover 40 is attached to the ionization chamber 10. Also, (A)
As shown in FIG.
A magnet 44 is provided at a position opposite to the side 4.

FIG. 4 shows a side view of the measuring section 12, which includes a cover identifying circuit 50 and a dose equivalent calculating circuit (not shown). A display unit 52 is provided on the upper surface, and displays the dose equivalent at each depth.

The cover identification circuit 50 receives signals from the pair of magnetic sensors 36 shown in FIG. 1 and determines whether or not the cover is attached and the type of the cover.
6 is determined. Each magnetic sensor is
They are arranged at both ends of the base portion 14 corresponding to the magnets 34 and 44.

Of course, as means for identifying the cover,
It is not limited to magnetically performed as in this embodiment, but it is also preferable to perform electrically or mechanically.

[0028]

[Effects of the Invention] As described above, according to the present invention,
By preparing the attenuation cover, it is possible to easily measure a plurality of dose equivalents depending on whether or not the cover is attached. Therefore, a dose equivalent meter useful for radiation protection can be provided.

Further, by providing means for identifying the type of the attenuation cover, it is possible to automatically identify the presence or absence and the type of the cover and automatically calculate an appropriate dose equivalent.

[Brief description of the drawings]

FIG. 1 is an external view showing the external appearance of a dose equivalent meter with a cover according to the present invention.

FIG. 2 is an external view showing the external appearance of a 3 mm dose equivalent measurement cover.

FIG. 3 is an external view showing the appearance of a 1 cm dose equivalent measurement cover.

FIG. 4 is a side view showing a side surface of the measurement unit.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Ionization chamber 12 Measuring part 14 Base part 16 Detecting part 18 Collector electrode 20 Case 30 3mm dose equivalent measurement cover 40 1cm dose equivalent measurement cover

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G01T 1/00-7/12

Claims (2)

(57) [Scope of request for utility model registration] 1. A detection unit for detecting radiation, said a freely mounted cormorants reduced <br/> weak cover covering the detection portion detachably attached to the detector, its presence and its time of mounting the mounting of the attenuation cover Attenuated
Identification means for identifying the type of cover, and calculating a dose equivalent according to the identification result of the identification means
And a calculating unit . 2. The dose equivalent meter with a cover according to claim 1, wherein when the attenuating cover is not attached, a 70 μm dose equivalent is measured, and a 3 mm dose equivalent is measured by attaching the first attenuating cover. A dose equivalent meter with a cover, wherein a 1 cm dose equivalent is measured by attaching an attenuation cover.