JPH06300850A - Pocket dose meter with alarm - Google Patents

Abstract

PURPOSE:To charge a NiCd battery used for the power supply of a pocket dose meter with alarm constantly under optimum conditions regardless of operating temperature. CONSTITUTION:When a worker exits from an exposure-controlled region, a pocket dose meter wish alarm being carried is inserted into a constant voltage power supply 13 which is a charging device. At this time, a radiation detector 1, an amplifier 2, and a comparator 3 stop functioning and a temperature detection element 9 and a charge control part 10 start operation instead. The charge control part 10 is constituted of a battery voltage detection part 11 and a constant current power supply part 12 and the constant current power supply part 12 starts charging a NiCd battery 8 rapidly. The NiCd battery 8 has characteristics where the battery voltage increases at the end of charging and the battery voltage detection part 11 detects the voltage increase and then sends the voltage detection signal to the constant current power supply part 12. The constant current power supply part 12 receiving the signal switches current from rapid charging to compensation charging.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pocket dosimeter with an alarm used for dose control of workers exposed to radiation such as nuclear power plants.

[0002]

2. Description of the Related Art Conventionally, a pocket dosimeter with an alarm of this kind is provided with a secondary battery such as a Ni-Cd battery (hereinafter referred to as a NiCd battery) as a power source in a dosimeter, and an operator charges the battery after finishing the work. It was configured to return the dosimeter to a storage area equipped with and to be charged by the time of use on the next day. With this configuration, the pocket dosimeter with alarm does not have a built-in charge control function, and is disclosed in, for example, Japanese Patent Laid-Open No. 57-96474
As disclosed in the publication, the charging control function is provided on the dedicated charging device side for storing and charging the pocket dosimeter.

[0003]

However, in such a conventional configuration, when used in a nuclear power plant, for example, the charging device is installed in a place other than the exposure control area kept at a constant temperature by air conditioning. On the other hand, a pocket dosimeter with an alarm is always carried by the worker and works in an exposure controlled area where temperature control by air conditioning is not performed. Therefore, the alarm pocket dosimeter has a problem that the temperature of the dosimeter main body changes depending on the temperature of the workplace, and the charging state changes depending on the environment in which the dosimeter is used when charged under constant charging conditions.

For example, when there is a temperature difference in the pocket dosimeter with alarm returned to the charging device, the terminal voltage of the battery during charging changes depending on the temperature of the battery. On the other hand, the charging device determines that charging is completed when the terminal voltage of the battery reaches a certain voltage regardless of the temperature of the battery, and switches from quick charging to compensation charging. For this reason, if the battery is returned in a low temperature state, the terminal voltage of the battery during charging will be high. Stop and switch to compensation charging. When the battery is returned in a high temperature state, the terminal voltage of the battery does not rise to the specified voltage even if the rapid charging is continued, and the rapid charging continues more than necessary. As a result, when the temperature of the battery is low, the charge becomes insufficient, and when the temperature of the battery is high, the battery is overcharged, which accelerates the deterioration of the NiCd battery, lowers the discharge capacity, and causes electrolyte leakage. There was a problem.

The present invention solves such a problem by charging a dosimeter main body and a built-in battery in a state where the temperatures of the dosimeter main unit and a built-in battery are significantly different depending on the environment in which the pocket dosimeter with alarm is used. It is an object of the present invention to provide a pocket dosimeter with an alarm that can prevent shortage and overcharge and always perform proper charging.

[0006]

In order to solve the above problems, the present invention provides a radiation detector, an amplifier for amplifying the output signal of the radiation detector, and a comparator for converting the output signal of the amplifier into a digital signal. , A microcomputer that counts / calculates the output signal of the comparator as a dose value, a memory unit that stores a program for executing the functions of the microcomputer, a display unit that displays the dose value, and send and receive the dose value as data. A constant voltage power supply using a Nicad battery as a power supply, and a temperature detecting element for detecting the temperature of the Nicad battery, and controlling the charging of the Nicad battery based on the information from the temperature detecting element. Is.

[0007]

According to the above construction, when the pocket dosimeter with alarm is returned from the worker to the charging device, even if there is a temperature difference between the charging device and the dosimeter, the temperature is detected inside the pocket dosimeter. Since the device and the charge controller based on the temperature signal are built-in, proper charging can always be performed. Therefore, it is possible to prevent the Nicad battery from being insufficiently charged or overcharged.
This will allow the Nicad battery to last longer.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An alarm pocket dosimeter according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows the configuration of a pocket dosimeter with an alarm according to this embodiment. In the figure, 1 is a radiation detector that detects the exposure radiation dose, 2 is an amplifier that amplifies the output of the radiation detector and sends it to the next circuit, 3 is a comparator, 4 is a microcomputer, 5 is a memory section, and 6 is a measurement result. , 7 is a communication unit for transmitting and receiving measurement results, 8 is a nicad battery which is a power source of the pocket dosimeter, 9 is a temperature detecting element for detecting the temperature of the nicad battery, and 10 is a temperature signal from the temperature detecting element. A charging control unit for controlling the charging of the NiCd battery under optimum conditions based on the above, 11 is a battery voltage detecting unit for detecting the terminal voltage of the NiCd battery, 12 is a constant current power supply unit for charging the NiCd battery, and 13 is a temperature detecting element 9 And battery voltage detection unit 11
It is a constant voltage power supply used in a charging device that operates according to the signal.

Next, the operation of the pocket dosimeter with alarm constituted by the above circuit blocks will be described. The radiation incident on the radiation detector 1 is converted into an electric signal by the radiation detector, amplified by the amplifier 2, and then input to the comparator 3 and converted into a digital signal. The microcomputer 4 counts the pulse signals of the radiation converted into digital signals, and the counting result is displayed on the display unit 6 as a dose value. Data communication with the entry / exit management device is performed by the communication unit 7. A program for performing the above series of operations is stored in the memory unit 5. A NiCd battery is installed as a power source for the above circuit.

When the worker exits the radiation controlled area, the pocket dosimeter with alarm carried by him is inserted into the constant voltage power source 13 which is a charging device. At this time, the radiation detector 1, the amplifier 2, and the comparator stop functioning, and instead, the temperature detection element 9 and the charge control unit 10 start operating. The charge control unit 10 is composed of a battery voltage detection unit 11 and a constant current power supply unit 12, and the constant current power supply unit 12 starts rapid charging of the nicad battery 8. The nickel-cadmium battery has a characteristic that the battery voltage increases at the end of charging, and the battery voltage detection unit 11 detects this voltage increase and sends a voltage detection signal to the constant current power supply unit 12. Upon receiving this signal, the constant current power supply unit 12 switches the current from quick charging to compensation charging.

Generally, when the ambient temperature is high and the battery temperature during charging is high, the battery terminal voltage of the nickel-cadmium battery 8 decreases, and when the ambient temperature is low and the battery temperature during charging is low, the battery during charging is low. The terminal voltage becomes high. In the alarm pocket dosimeter of the present embodiment, the temperature detection element 9 is connected to the battery voltage detection unit 11 to perform charging control so that the completion of charging can be appropriately detected according to the temperature of the battery. With this configuration, the nickel-cadmium battery can always be charged under optimum conditions without being affected by the usage environment of the dosimeter.

[0013]

As is apparent from the above description of the embodiments, according to the present invention, a pocket dosimeter with an alarm has a charge control function for setting a charge completion period based on a temperature detector and temperature information from the temperature detector. By incorporating it, even if there is a temperature difference between the pocket dosimeter with alarm and the charging device, the temperature detector detects the battery temperature, and the charging control unit always sets the optimum charging condition based on this temperature information. Therefore, it is possible to prevent the NiCad battery from being insufficiently charged or overcharged. Therefore, the nickel-cadmium battery can be used safely for a long period without deterioration or leakage of the nickel-cadmium battery.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a pocket dosimeter with an alarm according to an embodiment of the present invention.

[Explanation of symbols]

 1 radiation detector 2 amplifier 3 comparator 4 microcomputer 5 memory section 6 display section 7 communication section 8 nicad battery 9 temperature detecting element 10 charging control section 11 battery voltage detecting section 12 constant current power supply 13 constant voltage power supply

Claims (1)

[Claims] 1. A radiation detector, an amplifier for amplifying the output signal of the radiation detector, a comparator for converting the output signal of the amplifier into a digital signal, and a microcomputer for counting and calculating the output signal of the comparator as a dose value. A memory unit that stores a program for executing the functions of the microcomputer, a display unit that displays the dose value, and a communication unit that transmits and receives the dose value and the like as data. And a pocket dosimeter with an alarm provided with a temperature detection element for detecting the temperature of the NiCd battery during charging and a charging control unit for controlling the charging of the NiCd battery based on the temperature information from the temperature detection element.