JPH10197644A - Radiation measuring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To specify contaminated location in a survey meter efficiently without disturbed by background. SOLUTION: If a detection pulse 100 is detected with a wave-height discriminator 14, a pulse 102 having a specific width T is output from a one shot multivibrator 16. If another detection pulse 100 generates outside the width T, it is judged as background by AND circuits 18 and 20 and detection pulse other than the background is output as a measured result. Also only background can be output separately.

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, and more particularly to background identification and removal.

[0002]

2. Description of the Related Art A survey meter is known as one of radiation measuring apparatuses. This survey meter is usually configured as a portable type, and is used, for example, in identifying radiation contamination on a floor. That is, when the survey meter is positioned above the contaminated site, radiation from the contaminated site is detected, and the detection of the radiation is notified by light or sound.

[0003]

However, when radiation or cosmic rays in the air are detected by the survey meter, it is in spite of the fact that it is originally in the background.
It will be reported as above. The background is randomly generated, and it is difficult for a measurer to determine from the notification whether it is due to radioactive contamination or the background. Therefore, a complicated operation of re-searching the same area in order to identify the radiation contamination and recognizing that the background is present only when a similar notification cannot be obtained has been required.

The present invention has been made in view of the above-mentioned conventional problems, and an object of the present invention is to provide a radiation measuring apparatus capable of determining a background and excluding it from measurement results.

Another object of the present invention is to enable a survey meter to efficiently identify a contaminated portion without being distracted by the background.

[0006]

In order to achieve the above object, the present invention provides a radiation detector for detecting radiation, and a background determination means for monitoring the interval between the radiation detection pulses and determining the background. And a background removing unit that removes the detection pulse determined as the background, and an output unit that outputs a measurement result based on the detection pulse other than the background.

According to the above configuration, the background can be determined based on the pulse interval, and the background can be removed from the measurement result. Therefore, if the present invention is applied to a survey meter, it is possible to efficiently search for a contaminated site without being confused by bag lands.

In a preferred aspect of the present invention, the background determination means determines the background when the pulse interval is within a predetermined determination value, and includes a determination value setting means for variably setting the determination value. It is characterized by including. If the determination value can be changed, the background can be appropriately determined according to the situation.

In a preferred aspect of the present invention, the output means is at least one of a speaker, a light emitting device, and a meter display responding to a detection pulse other than the background.

[0010] In a preferred aspect of the present invention, in the normal mode, all the detected pulses are used as the measurement results, and in the background removal mode, the detection pulses other than the background are used as the measurement results. A mode selection unit for selecting the background removal mode.

[0011] According to the above configuration, the background removal mode can be selected when very high precision measurement is not required, such as when searching for a contaminated site, while the high accuracy measurement such as specific identification of the contaminated site and dose measurement can be performed. Is required, the normal mode can be selected.

Further, a radiation measuring apparatus according to the present invention monitors a radiation detector for detecting radiation and an interval between detection pulses of the radiation, and determines a background when the pulse interval is within a predetermined determination value. Background determining means, a background removing means for removing a detection pulse determined as the background, a first output means for outputting a measurement result based on a detection pulse other than the background, and the background And a second output unit that outputs the determined detection pulse as a background measurement result.

[0013] In a preferred aspect of the present invention, the first output means and the second output means have different output forms, respectively, and a measurement result based on a detection pulse other than the background and a measurement of the background are performed. The result can be identified and output.

In the above description, the pulse interval is used as the background determination criterion, but the concept also includes the frequency of pulse generation per unit time. The background may be determined by further considering the pulse level and the like.

[0015]

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

FIG. 1 shows a preferred embodiment of the radiation measuring apparatus according to the present invention, and FIG. 1 is a block diagram showing the entire configuration. This radiation measuring device is a survey meter for measuring radioactive contamination on a floor.

The detector 10 is, for example, a semiconductor detector for detecting radiation. A detection signal is amplified by an amplifier 12 and then input to a pulse height discriminator 14. Wave height discriminator 14
Outputs a detection pulse 100 when a signal having a certain peak value or more is input. The detection pulse 100 is input to the one-shot multivibrator 16.

This one-shot multivibrator 16
When a detection pulse 100 is input to the control unit, a pulse 102 having a predetermined pulse width T is output. The pulse 102 is for setting a gate period, and the pulse 1
02 is input to one input terminal (inverting input terminal) of the AND circuit 18. The above-described detection pulse 100 is input to the other input circuit of the AND circuit 18.

Therefore, the AND circuit 18 detects the detection pulse 100 in a period other than the pulse width T of the pulse 102.
When an is obtained, an output pulse is output. That is,
The AND circuit 18 functions as a background specifying / extracting unit, and a detection pulse as a background is output from the AND circuit 18.

The pulse 102 output from the one-shot multivibrator 16 is input to one input terminal of another AND circuit 20, and the detection pulse 100 is input to the other input terminal. Therefore, in the AND circuit 20, when the detection pulse 100 is obtained within the period corresponding to the width of the pulse 102, it is output as an output signal. That is, the AND circuit 20 functions as a background determination unit and a background removal unit. When the pulse interval of the detection pulse 100 is within a predetermined determination value T, the AND circuit 20 determines that the detection pulse is a detection pulse other than the background. The detection pulse is output from the AND circuit 20 as its output.

The output pulse output from the AND circuit 18 and the output pulse output from the AND circuit 20 are both input to the output device 22. Further, the detection pulse 100 itself is input to the output device 22 as it is. The mode selector 24 is a means for selecting the normal mode or the background removal mode by the user. When the normal mode is selected, the signal selector 2 is output to the output device 22.
The detection pulse 100, which is a normal signal, is input as it is via 6. Then, an output corresponding to the detection pulse is generated. On the other hand, when the background removal mode is selected by the mode selector 24, the output pulse from the AND circuit 20 is selected by the signal selector 26, whereby an output corresponding to a detection pulse other than the background is generated. In either mode, for example, the output pulse of the AND circuit 18 may be further selected by the signal selector 26, and the output of the output pulse may be generated in an output form different from other outputs.

The output device 22 is composed of, for example, a speaker, a light emitting diode, a rate meter, or the like. The output device may be provided for each signal, or a common output device may be provided for each signal. Good. Output device 22
Various modifications are conceivable for the specific configuration of. For example, a sound may be generated in response to a detection pulse other than the background while displaying the normal detection pulse 100 with light. Alternatively, only the background may be identified by the generation of light while the normal detection pulse is generated by sound. In any case, according to the configuration shown in FIG. 1, both the normal detection pulse and the background can be identified separately, so that various output modes can be adopted.

A gate period setting device 28 is provided for setting a gate period according to the amount of background. The gate period setting unit 28 sets the pulse width T of the pulse 102, that is, the pulse width T of the output pulse of the one-shot multivibrator 16 is set by the gate period setting unit 28. As a result, the determination value for determining the background can be changed by the user. For example, in a measurement environment where the background is large, the gate period T can be set relatively short.

[0024]

As described above, according to the present invention,
It is possible to provide a radiation measuring apparatus capable of determining the background and excluding it from the measurement result.In particular, according to the present invention, there is an advantage that a survey meter can efficiently identify a contaminated portion without being confused by the background. is there.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a preferred embodiment of a radiation measuring apparatus according to the present invention.

[Explanation of symbols]

10 detector, 12 amplifier, 14 wave height discriminator, 16
One-shot multivibrator, 18, 20 AND circuit, 22 output device, 24 mode selector, 26
Signal selector, 28 gate period setting device.

Claims (8)

[Claims] A radiation detector that detects radiation; a background determination unit that monitors intervals of the radiation detection pulses to determine a background; and a background that removes the detection pulses determined as the background. A radiation measuring apparatus comprising: a removing unit; and an output unit that outputs a measurement result based on a detection pulse other than the background. 2. The apparatus according to claim 1, wherein the background determination unit determines that the background is the background when the pulse interval is within a predetermined determination value, and sets the determination value variably. A radiation measuring device comprising means. 3. The radiation measuring apparatus according to claim 1, wherein the output means is a speaker that responds to a detection pulse other than the background. 4. The radiation measuring apparatus according to claim 1, wherein the output means is a light emitter that responds to a detection pulse other than the background. 5. The radiation measuring apparatus according to claim 1, wherein the output means is a meter display responding to a detection pulse other than the background. 6. The apparatus according to claim 1, wherein in the normal mode, all detection pulses are used as measurement results, and in the background removal mode, detection pulses other than the background are used as measurement results. A radiation measurement apparatus comprising a mode selection unit for selecting a mode or the background removal mode. 7. A radiation detector for detecting radiation, background determining means for monitoring an interval between detection pulses of the radiation, and determining a background if the pulse interval is within a predetermined determination value; Background removal means for removing a detection pulse determined to be ground, first output means for outputting a measurement result based on the detection pulse other than the background, and background measurement of the detection pulse determined to be the background And a second output means for outputting as a result. 8. The apparatus according to claim 7, wherein the first output means and the second output means have different output forms, respectively, and a measurement result based on a detection pulse other than the background and the background. A radiation detection device capable of distinguishing between the measurement result of the radiation detection device