JPH06214039A - Radiation measuring device - Google Patents

Abstract

PURPOSE:To judge and alarm a failure when a detected fluctuation quantity is smaller than a preliminarily set minimum fluctuation quantity, and perfectly detect the failure of a measuring system to improve reliability. CONSTITUTION:The level of radiation is outputted as the signal of a corresponding voltage level by a determined time constant by a radiation measuring part 12 through a radiation detector 11. A fluctuation detecting part 15 converts 15a this signal to a digital data, and updates and holds 15b the maximum and minimum values of the digital data sampled in a sampling period T2 during a period time T1 for monitoring a failure. The fluctuation quantity is calculated 15c from the maximum and minimum values, and when it is judged smaller than a set 15d minimum fluctuation value, a failure signal is outputted to a failure alarming means 16 to alarm the failure of a measuring system. Namely, by providing the fluctuation detecting part 15, when the measuring system is failed, the failure of the measuring system even below the minimum fluctuation value can be perfectly detected and alarmed even when the voltage level is fixed at a conventional measurement lower limit value or more to improve reliability.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radiation measuring apparatus for detecting radiation and measuring the radiation dose of the detected radiation per preset time.

[0002]

2. Description of the Related Art FIG. 3 shows a block diagram of a circuit configuration of a main part of a conventional radiation measuring apparatus. The radiation detector 1 that detects radiation by its electromagnetic force action outputs a pulse signal (current signal) corresponding to the radiation level of the surroundings to the radiation measuring unit 2. The radiation measuring unit 2 outputs a signal of a voltage level corresponding to the number of pulses of the pulse signal (current amount of the current signal) input from the radiation detector 1 at preset time intervals. Has become. The voltage signal output from the radiation measuring unit 2 is input to the instruction unit 3 and the recording unit 4 and also to the lower limit determination unit 5.

The indicator 3 displays the value of the radiation level corresponding to the input voltage level, for example, by an indicator needle of a meter or a liquid crystal display. In the recording unit 4, the voltage levels are sequentially recorded on a storage medium such as recording paper.

The lower limit determination unit 5 compares the voltage signal input from the radiation measurement unit 2 with the measurement lower limit value (minimum voltage level) preset by the measurement lower limit value setting unit 6 to determine the voltage signal Determine if the voltage level is above the lower measurement limit. Here, when the voltage level of the voltage signal is less than the measurement lower limit value, an abnormality signal is output to the failure notification means 7. The failure notifying means 7 notifies the failure of the measurement system when an abnormal signal is input from the lower limit determination unit 5.

[0005]

As described above, in the conventional radiation measuring apparatus, for example, when the connection cable from the radiation detector 1 to the radiation measuring section 2 is broken,
The voltage signal input from the radiation measurement unit 2 to the lower limit determination unit 5 has the lowest voltage level, and this voltage signal falls below the measurement lower limit value set by the measurement lower limit value setting unit 6 in the lower limit determination unit 5, so the measurement system The failure will be reported and no problem will occur.

However, for example, when the electronic components constituting the radiation detector 1 and the radiation measuring section 2 fail, the voltage signal from the radiation measuring section 2 continues to output a constant voltage. Moreover, it is possible that the constant voltage of the voltage signal is higher than the measurement lower limit value set by the measurement lower limit value setting unit 6.

In such a case, since the voltage signal output from the radiation measuring unit 2 is equal to or higher than the measurement lower limit value set by the measurement lower limit value setting unit 6, the lower limit judging unit 5 judges that the measuring system is out of order. Therefore, no abnormality signal is output to the failure notification means 7. Therefore, the failure leaving means 7 also does not notify the failure of the measurement system. That is, the conventional radiation measuring apparatus has a problem that the failure of the measurement system cannot be completely detected depending on the failure state. Therefore, an object of the present invention is to provide a radiation measuring apparatus capable of completely detecting and notifying a failure of a measuring system and improving reliability.

[0008]

SUMMARY OF THE INVENTION The present invention relates to a radiation measuring apparatus for detecting radiation and measuring the radiation dose per preset time of the detected radiation. A fluctuation detecting means for detecting the fluctuation amount in the above, and a notifying means for judging that the apparatus is in failure and notifying the fluctuation amount detected by the fluctuation detecting means is smaller than a preset minimum fluctuation amount. Is.

[0009]

In the present invention having such a structure, the fluctuation amount in the measured radiation amount per set time is detected by the fluctuation detecting means, and the fluctuation amount detected by the fluctuation detecting means is set to the preset minimum fluctuation. When the amount is smaller than the amount, the notification means determines that the device is in failure and notifies it.

[0010]

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

FIG. 1 is a block diagram showing a circuit configuration of a main part of a radiation measuring apparatus to which the present invention is applied. 11 is a radiation detector that detects radiation by its electromagnetic interaction,
Pulse signal (current signal) corresponding to ambient radiation level
Is output to the radiation measuring unit 12. This radiation measuring unit 12
Then, a signal of a voltage level corresponding to the number of pulses of the pulse signal (current amount of the current signal) input from the radiation detector 11 is output with a preset time constant. The voltage signal output from the radiation measuring unit 12 is input to the instruction unit 13 and the recording unit 14 as well as to the fluctuation detecting unit 15.

The indicating section 13 displays the value of the radiation level corresponding to the voltage level of the input signal by, for example, a pointer of a meter or a liquid crystal display. Further, in the recording section 14, the numerical values of the radiation level corresponding to the voltage level are sequentially recorded on a storage medium such as recording paper.

The fluctuation detector 15 converts the voltage level of the input voltage signal (analog signal) into digital data, and an A / D (analogue / digital) converter 15a.
And a maximum value and a minimum value of the numerical values of the digital data output from the A / D conversion unit 15a sampled at a constant sampling period T2 during a preset period time (period time for monitoring a failure) T1. And a holding means 15b for updating and holding, a fluctuation calculating portion 15c for calculating a fluctuation amount from the maximum value and the minimum value held by the holding means 15b, and a minimum fluctuation value setting portion 15d for setting a minimum fluctuation value in advance. When the fluctuation amount from the fluctuation calculation unit 15c and the minimum fluctuation value from the minimum fluctuation value setting unit 15d are compared and it is determined that the fluctuation amount is smaller than the minimum fluctuation value, the measurement system is out of order. It is composed of a fluctuation determination unit 15e that outputs a failure signal to the failure notification unit 16 that notifies that there is an occurrence.

The holding means 15b and the fluctuation calculating section 15c constitute fluctuation detecting means,
The minimum fluctuation value setting unit 15d, the fluctuation determination unit 15
e and the failure notification means 16 constitute a notification means.

In the present embodiment having such a configuration, the radiation level is converted into a voltage level signal corresponding to the radiation level by the time constant preset by the radiation measuring unit 12 via the radiation detector 11. Is output.
The voltage level of this signal is converted into digital data by the A / D conversion unit 15a, and the sampling period T2 during the period T1 for monitoring the failure by the holding means 15b.
The maximum and minimum numerical values of the digital data sampled by are updated and held. The fluctuation amount is calculated from the held maximum value and minimum value by the fluctuation calculation unit 15c, and this fluctuation amount is determined to be smaller than the minimum fluctuation value set by the minimum fluctuation value setting unit 15d by the fluctuation determination unit 15e. Then, a failure signal is output to the failure notification means 16. As a result, the notification means 16 notifies that the measurement system is out of order.

In general, there is a radiation fluctuation due to the background, and if the minimum fluctuation value is set by the minimum fluctuation value setting section 15d in consideration of the fluctuation amount of the radiation due to this background, the normal measurement system must have a failure. For example, since the fluctuation amount calculated by the fluctuation calculation unit 15c is larger than the set minimum fluctuation value, the failure notification means 16 does not notify the failure of the measurement system.

For example, when a circuit such as the radiation detection unit 11 or the radiation measurement unit 12 has an abnormality, the voltage level of the signal output from the radiation measurement unit 12 is a conventional radiation measurement for determining whether or not there is a failure. When it becomes constant above the lower limit value, the fluctuation amount calculated by the fluctuation calculation unit 15c is close to 0, and becomes smaller than the minimum fluctuation value set by the minimum fluctuation value setting unit 15d. The failure notification means 16 notifies that there is.

Further, when an abnormality occurs in a circuit such as the radiation detection unit 11 or the radiation measurement unit 12, the voltage level of the signal output from the radiation measurement unit is the lower limit of the radiation measurement for determining whether or not there is a conventional failure. Even if it is less than the value, the fluctuation amount calculated by the fluctuation calculation unit 15c is close to 0,
Since it is smaller than the minimum fluctuation value set by the minimum fluctuation value setting unit 15d, the notification means 16 notifies that the measurement system has a failure.

As described above, according to this embodiment, the holding means 15b and the fluctuation calculating section 15c for detecting the fluctuation level of the radiation level, and the minimum fluctuation value set by the minimum fluctuation value setting section 15d for this fluctuation quantity. By providing the failure notification means 16 for notifying the failure when the fluctuation determination unit 15e determines that the fluctuation is smaller, it can be confirmed whether or not the fluctuation amount of the radiation is detected, and when the fluctuation amount cannot be detected. A failure can be reported. Therefore,
Conventionally, the fluctuation amount becomes almost 0 when a failure that outputs a constant voltage above the measurement lower limit value of the radiation level (minimum level of background) that could not be detected as a failure of the measurement system in the past, becomes almost zero. It can be determined that the failure.

That is, since the fluctuation amount of the radiation cannot be detected when the measurement system is out of order, the present embodiment can completely detect and inform the failure of the measurement system.
The reliability can be improved.

Further, conventionally, when the time constant of the measuring system is made small to improve the followability of the measurement, the fluctuation amount of the radiation becomes large and falls below the measurement lower limit value of the radiation for judging a failure. However, according to the present embodiment, since the failure of the measurement system is determined by the fluctuation amount of the radiation, the minimum fluctuation value setting unit 5d determines the minimum fluctuation value. It is only necessary to set the settings appropriately according to the time constant of the measurement system, and the effect that no bug source is required is also obtained. Another embodiment of the present invention will be described below with reference to FIG.

FIG. 2 is a block diagram showing a circuit configuration of a main part of a radiation measuring apparatus to which the present invention is applied. 21 is a radiation detector that detects radiation by its electromagnetic interaction,
Pulse signal (current signal) corresponding to ambient radiation level
Is output to the radiation measuring unit 23 and the fluctuation detecting unit 24 via the branching unit 22.

The radiation measuring unit 23 outputs a voltage level signal corresponding to the number of pulses of the pulse signal (current amount of current signal) input from the radiation detector 21 with a preset time constant. Has become.

The voltage signal output from the radiation measuring unit 23 is input to the instructing unit 25 and the recording unit 26, and in the instructing unit 25, the radiation level value corresponding to the voltage level of the input signal is set. For example, it is displayed by an indicator needle of a meter, a liquid crystal display, or the like, and the recording unit 26 sequentially records a numerical value of a radiation level corresponding to the voltage level on a storage medium such as a recording sheet.

The fluctuation detector 24 converts a pulse number (current amount) of a pulse signal (current signal) input from the radiation detector 21 through the branching means into a digital counter (A / D). (Analogue / digital)
Conversion unit) 24a and the pulse counter (A / D conversion unit) 2 sampled at a constant sampling period T2 during a preset time (time to monitor failure) T1.
Hold means 24b for updating and holding the maximum and minimum values of the numerical values of the digital data output from 4a, and a fluctuation calculating section 24c for calculating the amount of fluctuation from the maximum and minimum values held by this holding means 24b. , The minimum fluctuation value setting unit 24d that sets the minimum fluctuation value in advance, the fluctuation amount from the fluctuation calculation unit 24c and the minimum fluctuation value from the minimum fluctuation value setting unit 24d are compared, and the fluctuation amount is the minimum. When it is determined that the value is smaller than the fluctuation value, the failure notification means 2 that reports that the measurement system is in failure.
7 and a fluctuation determination unit 24e that outputs a failure signal.

The holding means 24b and the fluctuation calculating section 24c constitute fluctuation detecting means,
The minimum fluctuation value setting unit 24d, the fluctuation determination unit 24
e and the failure notification means 27 constitute notification means.

In this embodiment having such a structure, the radiation level is converted into a pulse signal (current signal) by the radiation detector 21, and the pulse signal is directly passed through the branching means 22 to the pulse counter (A / D converter). 24a is input.

In the pulse counter (A / D converter) 24a, the number of pulses (current amount) of the input pulse signal (current signal) is converted into digital data, and the digital data is monitored for a failure by the holding means 24b. During the cycle time T1, the maximum value and the minimum value of the numerical values of the digital data sampled in the sampling cycle T2 are updated and held. The fluctuation amount is calculated by the fluctuation calculation unit 24c from the held maximum value and minimum value, and the fluctuation amount is
The minimum fluctuation value setting unit 24d by the fluctuation determination unit 24e.
When it is determined that the value is smaller than the minimum fluctuation value set by, the failure signal is output to the failure notification unit 27. As a result, the notification means 27 notifies that the measurement system is out of order.

This embodiment also has the same structure as the above-described embodiment except that the signal from the radiation detector 21 is directly input to the pulse counter (A / D converter) 24a. , In consideration of the fluctuation of radiation due to the background, if the minimum fluctuation value is set by the minimum fluctuation value setting unit 24d, if there is no failure in the normal measurement system, a fluctuation amount larger than the minimum fluctuation value is detected,
The failure notification means does not notify the failure of the measurement system.
Further, when an abnormality occurs in a circuit such as the radiation detection unit 21 and the signal input from the radiation detection unit 21 via the branching unit 22 becomes constant, the detected fluctuation amount is close to 0, Since it is smaller than the minimum fluctuation value, the failure notification means 27 notifies that the measurement system has a failure.

As described above, also in this embodiment, the same effect as that of the above-described embodiment can be obtained. Further, in this embodiment, the signal from the radiation detector 21 is directly fed to the fluctuation detector 24 (pulse counter (A
/ D converter) 24a), the time constant of the measurement system is set to be large, and even when the fluctuation of the radiation level instructed or recorded by the instructing unit 25 and the recording unit 26 becomes small, It is possible to obtain the effect that the fluctuation amount of radiation can be detected regardless of the time constant.

In the above embodiments, the conventional measurement lower limit value of radiation does not judge the failure of the measurement system, but the present invention is not limited to this, and the fluctuation of radiation according to this embodiment is not limited. The determination of the failure of the measurement system based on the amount and the conventional determination of the failure based on the lower limit of measurement of radiation may be used together.

[0032]

As described above in detail, according to the present invention,
It is possible to provide a radiation measuring apparatus capable of completely detecting and notifying a failure of a measurement system and improving reliability.

[Brief description of drawings]

FIG. 1 is a block diagram showing a circuit configuration of essential parts of an embodiment of the present invention.

FIG. 2 is a block diagram showing a circuit configuration of a main part of another embodiment.

FIG. 3 is a block diagram showing a circuit configuration of a main part of a conventional example.

[Explanation of symbols]

11 ... Radiation detector, 12 ... Radiation measuring section, 15 ... Fluctuation detecting section, 15b ... Hold means, 15c ... Fluctuation calculating section, 15d ... Minimum fluctuation value setting section, 15e ... Fluctuation determining section, 16 ... Failure informing means.

Claims (1)

[Claims] 1. A radiation measuring apparatus for detecting a radiation and measuring a radiation dose of the detected radiation per preset time, a fluctuation for detecting a fluctuation amount in the measured radiation dose per the set time. A radiation measuring apparatus comprising: a detection unit; and an informing unit that determines that the device is out of order when the fluctuation amount detected by the fluctuation detection unit is smaller than a preset minimum fluctuation amount and notifies the failure. .