JP3054841B2 - Pocket dosimeter with alarm - Google Patents

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 which is used for controlling a worker's exposure dose in a place where radiation is handled, such as a nuclear power plant.

[0002]

2. Description of the Related Art Conventionally, a pocket dosimeter with this type of alarm has a secondary battery (hereinafter referred to as a NiCd battery) such as a Ni-Cd battery as a power source in a dosimeter, and a charging device is provided after an operator finishes work. The dosimeter was returned to the storage location equipped with the, and was configured to be charged by the time of use the next day. In this configuration, the pocket dosimeter with an alarm does not have a built-in charge control function.
As disclosed in Japanese Unexamined Patent Publication, a charge control function is provided on a side of a dedicated charging device that stores and charges a pocket dosimeter.

[0003]

However, in such a conventional configuration, for example, when used in a nuclear power plant, the charging device is installed in a location other than the exposure control area maintained at a constant temperature by air conditioning. On the other hand, pocket dosimeters with alarms are always carried by workers and work in exposure control areas where temperature control by air conditioning is not performed. Therefore, the pocket dosimeter with the alarm has a problem that the temperature of the main body of the dosimeter changes according to the temperature of the workplace, and when charged under a constant charging condition, the charging state changes depending on the environment in which the dosimeter is used.

For example, if there is a temperature difference between the pocket dosimeter with the alarm returned to the charging device, the terminal voltage of the battery at the time of charging changes according to 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 irrespective 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 at the time of charging becomes high. Stop and switch to compensation charging. Further, when the battery is returned in a high temperature state, the terminal voltage of the battery does not rise to a 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 battery is insufficiently charged, and when the temperature of the battery is high, the battery is overcharged. In any case, the deterioration of the NiCd battery is accelerated, and the discharge capacity decreases and the electrolyte leaks. There was a problem.

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

[0006]

SUMMARY OF THE INVENTION To solve the above problems, the present invention provides a radiation detector, an amplifier for amplifying an output signal of the radiation detector, a comparator for converting the output signal of the amplifier to a digital signal. , A microcomputer that counts and 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 transmits and receives the dose value as data. And a communication unit that uses a nickel-cadmium battery as a power source, constitutes a constant-voltage power supply, controls a temperature detection element that detects the temperature of the nickel-cadmium battery, and controls charging of the nickel-cadmium battery based on information from the temperature detection element. It is.

[0007]

According to the above configuration, when the pocket dosimeter with the 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 a charge control unit based on the element and the temperature signal is built in, proper charging can always be performed. Therefore, it is possible to prevent insufficient charging and overcharging of the NiCd battery,
The life of the NiCd battery can be kept long.

[0008]

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

FIG. 1 shows a configuration of a pocket dosimeter with an alarm of this embodiment. In the figure, 1 is a radiation detector for detecting the radiation dose, 2 is an amplifier for amplifying the output of the radiation detector and sending it to the next circuit, 3 is a comparator, 4 is a microcomputer, 5 is a memory, 5 is a measurement result. , A communication unit for transmitting and receiving measurement results, 8 a nickel-cadmium battery serving as a power supply for the pocket dosimeter, 9 a temperature detecting element for detecting the temperature of the nickel-cadmium battery, and 10 a temperature signal from the temperature detecting element. A charge control unit for controlling the charging of the nickel-cadmium battery to the optimum condition based on the above, a battery voltage detecting unit for detecting a terminal voltage of the nickel-cadmium battery, a constant current power supply unit for charging the nickel-cadmium battery, and a temperature detecting element 9 And battery voltage detector 11
Is a constant voltage power supply used for a charging device that operates according to the signal of

Next, the operation of the pocket dosimeter with alarm constituted by the above circuit blocks will be described. 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 to be converted into a digital signal. The microcomputer 4 counts the pulse signal of the radiation converted into the digital signal, 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 mounted as a power source for the above circuit.

When the worker leaves the exposure control area, the pocket dosimeter with alarm carried by the worker is inserted into the constant voltage power supply 13 which is a charging device. At this time, the functions of the radiation detector 1, the amplifier 2, and the comparator are stopped, and the temperature detection element 9 and the charge control unit 10 start operating instead. The charge control unit 10 includes 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 NiCd battery 8. The NiCd battery has a characteristic that the battery voltage rises at the end of charging, and the battery voltage detection unit 11 detects this voltage rise 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 the quick charge to the compensation charge.

Generally, when the ambient temperature is high and the temperature of the battery being charged is high, the battery terminal voltage of the battery decreases when the ambient temperature is high. The terminal voltage increases. In the pocket dosimeter with alarm of the present embodiment, the temperature detecting element 9 is connected to the battery voltage detecting unit 11 to perform charging control so that appropriate charging completion detection can be performed according to the battery temperature. 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 embodiment, according to the present invention, the pocket dosimeter with the alarm has a charging control function for setting the charging completion period based on the temperature information from the temperature detector and the temperature detector. Even if there is a temperature difference between the pocket dosimeter with alarm and the charging device, the battery temperature is detected by the temperature detector, and the charging control unit always sets the optimal charging condition based on this temperature information. Therefore, insufficient charging and overcharging of the nickel-cadmium battery can be prevented. Therefore, the nickel-cadmium battery can be used safely for a long period of time without causing deterioration or liquid leakage of the nickel-cadmium battery.

[Brief description of the drawings]

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

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Radiation detector 2 Amplifier 3 Comparator 4 Microcomputer 5 Memory part 6 Display part 7 Communication part 8 NiCd battery 9 Temperature detection element 10 Charge control part 11 Battery voltage detection part 12 Constant current power supply 13 Constant voltage power supply

Continuation of front page (56) References JP-A-64-26180 (JP, A) JP-A-4-262290 (JP, A) JP-A-4-353786 (JP, A) JP-A-60-42676 (JP) JP-A-59-10896 (JP, A) JP-A-57-96474 (JP, A) JP-A-5-203756 (JP, A) JP-A-5-264735 (JP, A) (58) Field surveyed (Int.Cl. ⁷ , DB name) G01T 1/17 G01T 1/15 H01M 10/44

Claims (1)

(57) [Claims] 1. A radiation detector, an amplifier for amplifying an 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 for storing a program for executing the functions of the microcomputer, a display for displaying the dose value, and a communication unit for transmitting and receiving the dose and the like as data. A pocket dosimeter with an alarm, comprising: a temperature detecting element for detecting a temperature of the NiCd battery at the time of charging; and a charge control unit for controlling charging of the NiCd battery based on temperature information from the temperature detecting element.