JPH0478953B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical field to which the invention pertains] This invention relates to a counting function check method of a radiation dosimeter that measures radiation dose, and in particular to a radiation dosimeter that makes the checking operation safe, easy, and economical. Concerning methods that can be carried out for the whole.

[Prior art and its problems]

FIG. 3 is a configuration diagram of a conventional radiation dosimeter.
In the figure, radiation is converted by radiation detection means 15 into an electric pulse signal 15a whose pulse frequency corresponds to the dose rate of the radiation. This signal 15a is then counted and integrated by the counter 3, and the integrated result is displayed on the display 12 as a radiation dose. Further, the integrated value by the counter 3 is compared with a preset value in the comparing means 17, and when the integrated value exceeds the set value, the buzzer 14 is activated to indicate that the radiation dose has exceeded the specified value. Dosimeter users are now notified.

Now, when checking the counting function of such a radiation dosimeter, conventionally, a reference radiation source for checking is used, the same measurement as above is performed on this radiation source, and the measured value is compared with the reference value. However, this check method has the problem that the reference radiation source is generally expensive, and its handling requires sufficient consideration for safety. For this purpose, an inexpensive and easy-to-handle pseudo-pulse generating means is provided in place of the reference radiation source, and the electric pulse signal outputted by this means is input to the counter 3 to check the counting function of the radiation dosimeter. However, such a check method has the problem that the function of the radiation detection means 15 cannot be checked.

[Purpose of the invention]

The present invention solves the problems of the conventional methods as described above, and provides a radiation dosimeter that allows checking operations to be performed extremely safely, easily, and economically on the entire radiation dosimeter including the radiation detection means. The purpose is to provide a counting function check method.

[Key points of the invention]

In order to achieve the above object, the present invention measures natural radiation while charging the storage battery in a radiation dosimeter with a built-in storage battery, and checks the counting function by comparing this measured value with a predetermined value. As a result, we have developed a radiation dosimeter that can safely, easily, and economically check the entire radiation dosimeter, including the radiation detection means, without using any special pulse generation means such as a reference radiation source or pseudo pulse generation means. This method is designed to provide a counting function check method.

[Embodiments of the invention]

FIG. 1 is a flowchart for explaining one embodiment of the present invention, and this figure shows the measurement operation and counting function check operation of the radiation dosimeter whose configuration is shown in FIG. 2. In addition, in FIG. 2, 1 is a radiation detector, 2 is an amplification/wave height discriminator, 3 is a counter,
4 is a timer, 5 is a central processing unit (CPU) such as in a microcomputer, 6 is an input circuit, 7 is a charging connector, 8 is a storage battery, 9 is a read only memory (ROM), 10 is a random access memory (RAM), 11 is a display circuit, 12 is a display device, 13
is an output circuit, and 14 is a buzzer. The radiation detection means 15 is composed of a radiation detector 1 and an amplification/wave height discriminator 2. 7a is a signal output when the connector 7 is connected to a charger (not shown);
8a is a power supply line that supplies power from the storage battery 8 to each part shown in the figure.

First, the measurement operation of the radiation dosimeter shown in FIG. 2 will be explained. That is, the detector 1 detects radiation and outputs a minute pulse signal 1a. This pulse signal is converted into a countable pulse signal 15a by the amplification/wave height discriminator 2, and then integrated and counted by the counter 3. This count value N is read by the CPU 5 and sent to the display circuit 11 as display data, and this is displayed on the display 12 as a dose value. The CPU 5 compares this count value N with an alarm setting value _Ns preset in the ROM 9 or RAM 10, and when the count value N, which is the content of the counter 3, is larger, it operates the output circuit 13 and outputs a buzzer. 14 to issue an alarm.

Next, the checking operation of the counting function of the radiation dosimeter shown in FIG. 2 will be explained with reference also to FIG. FIG. 1 shows the series of measurement operations described above.

When the charging connector 7 is not connected to a charger (not shown), the signal 7a is not output.
The radiation dosimeter is performing measurement operations (see Figure 1). Now, when the connector 7 is connected to the charger, charging of the storage battery 8 is started, and a signal 7a indicating that charging is in progress is inputted from the connector 7 to the input circuit 6. Then, the CPU 5 determines that charging is in progress based on the information from the input circuit 6 (see FIG. 1), first resets the contents of the counter 3 (see the same), and causes the timer 4 to start counting a predetermined time τ. For example, τ is a time of one hour. Since the CPU 5 leaves the counter 3 in the operating state even after resetting the counter 3, the counter 3 is reset.
Thereafter, the pulses due to natural radiation inputted via the radiation detection means 15 are counted (see the same reference).
When the time τ ends and the timer 4 outputs a time-up signal (see the same), the CPU 5 reads the content N of the counter 3 and compares it with the set value N ₀ preset in the ROM 9 (see the same).
Then, if NN is not ₀ , the process branches to the step, waits until the charging signal 7a disappears, and outputs an alarm indicating that there is an abnormality in the counting function of the dosimeter (see the same reference). Setting value for the number of pulses
When the above-mentioned time τ is one hour, N ₀ is usually set to about several. The reason for outputting an alarm when NN is not ₀ is that when a failure occurs in a radiation dosimeter, the measured value N generally tends to become small, and on the other hand, if a failure occurs that causes the counted value N to become large. This is because such a dosimeter is a practically safe dosimeter even if it occurs in the dosimeter. The above setting value N ₀ is also 1 if the dosimeter has no abnormality in its counting function.
It also means that the sensitivity of the dosimeter is set so that it can count N ₀ or more pulses of natural radiation per hour.

Now, as mentioned above, the CPU 5 outputs an alarm in steps. This means that when the dosimeter is removed from the charger and the charging signal 7a disappears, the buzzer 14 is activated via the output circuit 13 to notify that there is an abnormality before starting to use the dosimeter. It is something. Of course, it is also possible to sound the buzzer 14 during charging, and in some cases, it is also possible to display an abnormality on the display 12. However, dosimeters usually require multiple charges (50 to 100).
Since this is done at the same time, it is easier and more practical to sound the buzzer when the dosimeter is removed from the charger, making it easier to identify an abnormal dosimeter.

In FIG. 1, N and N ₀ are compared, and if the result is NN ₀ , the dosimeter is judged to be normal for the above-mentioned reason. Therefore in this case
CPU5 resets the contents of counter 3 (first
(see figure), waits until the charging signal 7a disappears (see same), in other words, waits until charging connector 7 and the charger are disconnected, and then shifts to the above-mentioned measurement operation (see same).

In the dosimeter of FIG. 2, its counting function is checked using natural radiation as described above.
Therefore, such a check method does not use a special radiation source, so it is extremely safe and economical, and the check operation is easy. According to this method, the counting function of the entire radiation dosimeter including the radiation detection means 15 is checked.

〔Effect of the invention〕

As described above, in the present invention, natural radiation is measured while the storage battery is being charged in a radiation dosimeter with a built-in storage battery, and the counting function is checked by comparing this measured value with a predetermined value. Therefore, according to such a check method, there is no need to use a special pulse generation means such as a reference radiation source or a pseudo pulse generation means, so that the counting function of a radiation dosimeter can be checked safely, easily, and economically. effective. Further, in the present invention, since natural radiation is measured via the radiation detection means in the radiation dosimeter, it is possible to check the counting function of the entire radiation dosimeter including the detection means. Furthermore, according to the present invention, a counting function check is performed before using the dosimeter.
Such a check system also has the effect of eliminating the need to use a dosimeter in a malfunctioning state.

[Brief explanation of the drawing]

FIG. 1 is a flowchart for explaining one embodiment of the present invention, FIG. 2 is a configuration diagram of a radiation dosimeter that operates according to the flowchart in FIG. 1, and FIG. 3 is a configuration diagram of a conventional radiation dosimeter. It is. 8...Storage battery, 15...Radiation detection means, 15
a...Pulse signal.

Claims (1)

[Claims] 1. In a radiation dosimeter with a built-in storage battery that measures the radiation dose by counting pulse signals from a radiation detection means, measure the dose of natural radiation while the storage battery is being charged, and compare this measured value with a predetermined value. A method for checking the counting function of a radiation dosimeter, which is characterized in that the counting function is checked by the following.