JP2006266880A - Individual radiation exposure dosimeter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an individual radiation exposure dosimeter for printing a management code on an element plate in the individual radiation exposure dosimeter having the annular element plate. <P>SOLUTION: The individual radiation exposure dosimeter comprises a sensor using an OSL crystal or a thermoluminescent phosphor as a radiation detection material and the annular element plate for holding the sensor. Further, a dosimeter identification code for managing the dosimeter is recognized by annular arrangement by applying laser beams. The amount of individual exposure to radiation can be measured easily with this configuration. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a dosimeter used for radiation measurement, and more particularly to a dosimeter used for personal radiation exposure management of workers engaged in radiation work in a nuclear power plant or research institution, or for environmental radiation measurement in a radiation management facility.

  Thermofluorescence dosimeters, film badges, and glass dosimeters are used as dosimeters used for personal exposure management of workers engaged in radiation work at nuclear power plants and research institutions. In particular, the thermofluorescence dosimeter and the OSL crystal can be used repeatedly, so that they have an advantage in terms of operation cost compared to the film badge and many users.

  Personal exposure management using a thermofluorescence dosimeter will be described. FIG. 5 shows a configuration example of a personal exposure dosimeter used for personal exposure management using a thermofluorescence dosimeter having four detectors.

  A conventional personal dose dosimeter 6 includes a detection body 101 (three detection bodies are shown) that uses a thermophosphor such as calcium sulfate as a radiation detection material, and an element plate 102 that holds the detection body 101. This is a structure in which four portions of a holder 103 having a cylindrical structure for inserting and holding the element plate 102 therein and a hanger 104 provided with a clip so as to be easily attached to an operator's clothes are integrated.

  In the present specification, a combination of the four parts of the detection body 101, the element plate 102, the holder 103, and the hanger 104 is referred to as an individual exposure dosimeter 106, and the detection body 101, the element plate 102, the holder 103, A unit in which these three parts are integrated is called a dosimeter 116.

  Next, the measuring method of a thermofluorescence dosimeter will be described. As shown in Equation 1, the radiation dose is obtained by the product of the electric signal amount, the conversion constant, the sensitivity correction coefficient, and the apparatus correction coefficient.

  The amount of electrical signal is expressed as the amount of electrical signal that is emitted when the detector receives excitation energy, and is expressed using the number of pulses, the integrated value of the current value, or the like.

  The conversion constant is a constant for converting the electric signal amount into the radiation dose, and is determined by the component and amount of the detection body.

  The sensitivity correction coefficient is a correction coefficient for correcting variation in the detection body, and is expressed as a ratio between the light emission amount of the reference detection body and the light emission amount of the detection body.

  The device correction coefficient is a correction coefficient for correcting variation of the measuring device, and measures the electrical signal output from the light receiving unit that receives the light emitted when the detection body receives excitation energy and outputs an electrical signal, and the light receiving means. It is determined by the performance of the measurement unit that outputs as an electric signal amount.

  The device correction coefficient is expressed as a ratio between the radiation dose when the reference detector is measured with the reference measurement device and the radiation dose when the reference detector is measured with the measurement device.

  Next, the code system in personal exposure management will be described. The personal exposure dosimeter 106 includes a hanger 104 provided with a user management barcode (not shown) on which an ID number for uniquely identifying a user is printed. In addition, the dosimeter 116 includes a dosimeter management barcode 105 on which a dosimeter identification code for uniquely identifying the dosimeter is printed.

  FIG. 6 is a diagram showing a definition of a dosimeter identification code of a dosimeter having four detectors.

  The dosimeter identification code includes a dosimeter type code indicating a type of the dosimeter, a unique serial number, and a sensitivity rank code in which a sensitivity correction coefficient for each detection object is encoded. Furthermore, the dosimeter type code and the conversion constant correspond one-to-one, and if the dosimeter identification code is determined, the conversion constant can be uniquely determined. The sensitivity rank code indicates, for example, five sensitivity levels (0.76 to 0.85, 0.86 to 0.95, 0.96 to 1.05, 1.06 to 1.15, 1). .16 to 1.25), and 0, 1, 2, 3, 4 codes are defined for each. With this encoding method, sensitivity correction is performed at a management level of 0.10 units within a limited data amount range of the dosimeter identification code.

  The measuring apparatus stores a correspondence table of dosimeter type codes and conversion constants, and a correspondence table of sensitivity rank codes and sensitivity correction coefficients in the storage unit.

  As a method of providing optical information record carriers in personal exposure management, the user name / dosimeter management number and body positioning indicia are given to the dosimeter, and the personal exposure management is performed by attaching the dosimeter to the body position indicated by the body positioning indicia. The method of performing is disclosed (for example, patent document 1).

  Next, the OSL crystal will be described. The OSL crystal has been developed as a next-generation radiation detection material. As a measurement method when the OSL crystal is used as a dosimeter, a component of the OSL crystal, a laser irradiation method, and a light reception measurement method are disclosed (for example, Patent Document 2 and Patent Document 3).

Further, the irradiation optical path fiber and the light receiving fiber are bundled as one fiber, a dosimeter composed of an OSL crystal is attached to the tip of the fiber, and the irradiation optical path fiber is irradiated with laser light and emitted from the OSL crystal. A method for receiving and measuring OSL light with a light receiving fiber is disclosed (for example, Patent Document 4).
Special table 2001-508875 gazette JP 2000-503396 JP 2000-503759 gazette JP-A-11-237479

  However, it is difficult to secure a surface for printing a dosimeter identification code in a personal exposure dosimeter composed of one detector and an annular element plate. It was necessary to secure a separate space, and it was difficult to reduce the size.

  In order to solve the above-mentioned problems, the present invention provides a dosimeter identification code on an element plate of an annular personal exposure dosimeter using an OSL crystal or a thermophosphor.

  In order to achieve the above object, the personal exposure dosimeter of the present invention comprises a detector using an OSL crystal or a thermophosphor as a radiation detection material, and an annular element plate holding the detector, A dosimeter identification code is provided for managing the dosimeter.

  In the reading, a dosimeter identification code is irradiated with laser light, and the absorbed energy is exchanged for heat so that it is recognized as a character or a symbol.

  With the above-described configuration, the personal exposure dosimeter can give a dosimeter identification code for managing the dosimeter to the element plate.

  The personal dose dosimeter of the present invention is characterized in that the information for operating and managing the dosimeter is provided on both sides of the element plate. A constant / sensitivity correction coefficient is assigned to the other back surface, and an ID number that uniquely identifies the user as information for operating the dosimeter is assigned. In the case of environmental radiation measurement, a location ID number for uniquely identifying a location is assigned to the back surface.

  With the above configuration, the personal exposure dosimeter can directly record information for operating and managing the dosimeter on the element plate. In the conventional product, the type of the element plate cannot be directly known, and there was only a method of tracing from the information of the dosimeter identification code. You can know directly at.

  In the personal exposure dosimeter of the present invention, the dosimeter identification code is directly printed on the radiation detection material by laser light or silk printing.

  With the above configuration, the personal dose dosimeter can give a larger amount of information, and thus can give information such as the manufacturing lot number and expiration date of the detector.

  In the personal dose dosimeter of the present invention, the dosimeter identification code is provided by a bar code, and is arranged radially on a plane parallel to the radiation detection material of the annular element plate holding the radiation detection material. An element plate management number is assigned by arranging a bar code.

  With the above configuration, a large amount of information can be given even in a space where characters cannot be printed.

  In the personal dose dosimeter of the present invention, the dosimeter identification code is provided with a bar code on one side of the element plate and alphanumeric characters on the opposite side.

  With the above configuration, the personal dose dosimeter can visually read the element plate management number even when the barcode cannot be recognized.

  In the personal exposure dosimeter of the present invention, the dosimeter identification code is provided in the radiation detection material by the high-density optical information recording technique.

  With the above configuration, the personal exposure dosimeter of the present invention can record a dosimeter identification code in a limited area of the radiation detection material by high-density optical information recording represented by a two-dimensional code. Further, the size of the element plate can be further reduced.

  As described above in detail, according to the present invention, it is possible to provide a personal dose dosimeter that can be provided with a dosimeter identification code even if it is a personal dose dosimeter having an annular element plate. It has a great effect.

(Embodiment 1)
Embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 shows a block diagram of the personal exposure dosimeter of the present invention.

  The personal exposure dosimeter 6 includes a detection body 1 that uses an OSL crystal or a thermophosphor as a radiation detection material, an annular element plate 2 that holds the detection body 1, and a holder 3 that holds the element plate 2.

  The dosimeter identification code is recorded by the barcode 5 on the element plate 2. The dosimeter identification code is a dosimeter type code indicating the type of the dosimeter, a unique serial number (corresponding to a production lot number), a sensitivity correction coefficient of the detection body 1, an ID number for uniquely identifying the user, and the like.

  The configuration of the dosimeter identification code can be freely changed depending on the purpose of measurement, and is not limited to the above configuration.

  In addition to the printing means such as a barcode, the recording method may include a non-contact readable medium such as an RFID chip and an antenna on the element plate 2 and store a dosimeter identification code.

(Embodiment 2)
An embodiment of the personal exposure dosimeter will be described.

  FIG. 2 shows a printed example 1 of the dosimeter identification code of the personal exposure dosimeter of the present invention.

  FIG. 3 is a cross-sectional view taken along line A-A ′ of dosimeter identification code printing example 1 of the personal exposure dosimeter of the present invention.

  2 and 3, a detector 1 that uses an OSL crystal or a thermophosphor as a radiation detection material, an annular element plate 2 that holds the detector 1, and a holder 3 that holds the element plate 2 (as in the first embodiment) For the same reason, it is not shown), and is constituted by a cover film 9 covering the detection body 1. For the cover film 9, for example, a PET resin is formed in a film shape and is attached to the element plate 2 with an adhesive.

  The dosimeter identification code is recorded as a high-density optical information record 7 such as a two-dimensional code by irradiating a laser beam on the detector 1 that is a radiation detection material, and is used with a cover film 9 attached.

  Further, after the cover film 9 covering the detector 1 is attached, the cover film 9 may be recorded as a high-density optical information record 7 such as a two-dimensional code by irradiating a laser beam.

  By recording with the high-density optical information recording 7 such as a two-dimensional code, a lot of information can be given.

  In addition, since the width of the edge portion of the element plate 2 can be reduced by providing the information recording position on the upper surface of the detector 1, further downsizing can be achieved as compared with the first embodiment.

(Embodiment 3)
An embodiment of the personal exposure dosimeter will be described.

  FIG. 4 shows a dosimeter identification code printing example 2 of the personal exposure dosimeter of the present invention.

  By providing the dosimeter identification code with the bar code 5 on one side of the element plate 2 and the alphanumeric 8 on the opposite side, a lot of information can be given.

  A dosimeter identification code is assigned to a dosimeter identification code by arranging a bar code arranged radially on a surface parallel to the detector 1 of the element plate 2, and character information is printed on the opposite surface. Thus, even when the bar code 5 cannot be recognized, it is possible to visually read the character information as a part of the dosimeter identification code.

  Although the personal dose dosimeter of the present invention is small, it can be equipped with operation management information, and even when barcodes, two-dimensional codes, etc. cannot be read, the alphanumeric element plate management number is visually recognized. This is useful for dosimeters.

Configuration of personal dose dosimeter of the present invention The figure which shows the dosimeter identification code printing example 1 Sectional view of the dosimeter identification code printing example 1 The figure which shows the example 2 of the same dosimeter identification code printing Figure showing a configuration example of a conventional personal dose dosimeter The figure which shows the definition of the dosimeter identification code of a dosimeter with four detection bodies

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Detector 2 Element plate 3 Holder 4 Hanger 5 Bar code 6 Personal exposure dosimeter 7 High-density optical information record 8 Alphanumeric 9 Cover film 16 Dosimeter

Claims (6)

A dosimeter having a detector using an OSL crystal or a thermophosphor as a radiation detection material and an annular element plate holding the detector, the dosimeter identifying the dosimeter for managing the dosimeter on the element plate A personal dose dosimeter comprising a cord. The individual dose dosimeter according to claim 1, wherein the dosimeter identification code is provided on both sides of the annular element plate. The personal dose dosimeter according to claim 1, wherein the dosimeter identification code is provided in the radiation detection material. The personal dose dosimeter according to claim 1 or 2, wherein the dosimeter identification code is provided by a bar code. 4. The personal exposure dosimeter according to claim 1, wherein the dosimeter identification code comprises a bar code on one side of the annular element plate and alphanumeric characters on the facing side. The personal exposure dosimeter according to claim 3, wherein the dosimeter identification code is provided in the radiation detection material by a high-density optical information recording technique.

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