JPS62245983A - Radiation measuring instrument - Google Patents

Abstract

PURPOSE:To test a radiation measuring instrument without interrupting measuring operation by detecting a fault of a radiation detection part with a fault signal and calibrating a measurement part with a calibration signal. CONSTITUTION:An arithmetic circuit 16 consisting of a gate circuit 12 and an AND circuit 14 performs logical operation between a reference signal 7a and the detection signal 4a of the radiation detection part 5 to outputs a calibration signal 14a corresponding to the signal 7a when the signal 7a is in a pulse generation state or a measurement signal 12a corresponding to the signal 4a when the signal 7a is in a pulse extinction state. For the purpose, the signal 14a is inputted to the measurement part 15 through a changeover switch 13 to calibrate the measurement part 15; and the signal 12a is inputted to the measurement part 15 and the signal 14a is inputted to a measurement part to be calibrated, so that the measurement part to be calibrated is calibrated while a measurement is taken by the measurement part 15. Further, if the detection part 5 gets out of order, a NOR circuit 10 performs logical operation between the signal 7a and the output signal 9d of an FF circuit 9 and sends out its output signal 10a as a fault signal, so that the fault is displayed 11.

Description

[Detailed Description of the Invention] [Technical Field to which the Invention Pertains] The present invention relates to a radiation measuring device using a detector sensitive not only to radiation but also to light, such as a scintillation detector or a semiconductor detector. The present invention relates to a device configuration that can easily check for the presence or absence of a failure and whether it is around 0 (hereinafter, such an inspection may simply be referred to as an inspection).

[Prior art and its problems]

Conventionally, radiation measuring devices such as those mentioned above have been inspected using various methods as explained below.
Each has problems as described below.

In other words, the first inspection method is that when a dot-eating radiation source is brought close to a radiation measurement device that is measuring radiation, if the radiation measurement device is normal, the measurement device will detect the dose of radiation to be measured. The indicated value should increase by detecting the radiation dose (σ) from the inspection radiation source (at 0). This method has a problem in that during the inspection, the indicated value of the radiation measuring device naturally no longer corresponds to the dose of the radiation to be filled, so the measurement of the radiation line to be measured must be interrupted.Second Inspection The method is to always place a weak radiation source near the radiation measuring device that generates a low level of radiation that is within the tolerance range for the maximum radiation level that can be measured by the radiation measuring device 1VC. An inspection method that determines that a failure has occurred in the 6111 measurement device when the indicated value of a radiation measurement device based on a 4m source of weak radiation becomes zero!The advantage of this inspection method is that it can constantly monitor whether or not a failure has occurred. However, if such a second inspection method is used, in a radiation measuring device equipped with a weak radiation source such as the above C0, if the radiation to be measured is at a low level, the radiation level due to the weak radiation source will be measured. The tolerance will be exceeded (if it is 0, there is a problem that low-level radiation cannot be measured.Inspection using the second inspection method is performed using an 11-ta weak pulsed light emitting source instead of a weak radiation source. However, it is clear that in this case as well, an open circuit similar to the one described above will occur.Each of the above-mentioned inspection methods requires a detector unit such as a scintillation detector θ) and a After amplifying the signal output from the section, various signal processing is performed to produce ゛C radiation 41j! However, this method was performed for the entire radiation measuring device rO, which consists of a signal processing section that issues instructions, etc.

Next, a third conventional inspection method for the signal processing section will be explained. That is, in this inspection method, a reference signal generation source and signal switching means such as relays and switches are prepared in place of the detector section, and the output 4 of the detector section is
The signal and the output signal of the reference signal generation source are switched by the signal switching means and input to the signal processing section, and the radiation 'tt (n) in the processing section is checked based on the indicated value. , In this case 5. Normally, the signals output from the detector section and the reference signal source rO are extremely small, so measures to prevent noise intrusion and signal leakage must be taken very carefully for the transmission paths of these small signals. Therefore, the third inspection method VC has a problem in that the configuration of the inspection circuit is complicated and inspection work is troublesome.

[Purpose of the invention]

The present invention solves the above-mentioned conventional inspection problems in a radiation measuring device using a detector sensitive to light such as a scintillation detector, and inspects the presence or absence of failure, the degree of failure, etc. without causing an increase in the measurable radiation level, without interrupting the measurement of the radiation to be measured, and without switching the transmission path of the output signal of the detector section in the radiation measuring device. The purpose of this invention is to provide a radiation measuring device that can be used for one diagnosis.

[Key points of the invention]

In order to couple the above objectives, the present invention constantly forcibly irradiates a radiation detection unit that outputs a detection signal corresponding to the incidence of radiation or light with a light pulse train in the form of a reference pulse train. Calibration work is performed on the measurement signal corresponding to the detection signal and the measurement unit that performs radiation 0-line ilt measurement using the measurement signal by performing a logical operation using the electric pulse train reference signal for optically driving the balster 11 and the detection signal. A calibration signal that serves as a reference is always output, and a failure signal is automatically output when the radiation detection unit malfunctions, so that the measurable radiation level does not increase and the radiation to be measured is without interrupting the measurement of
This allows inspection of the radiation 6111 standard f-.

[Embodiment of the Invention] FIG. 1 is a diagram showing an η'1jIs diagram of an embodiment of the present invention. In FIG. 1, l is sensitive to both radiation and light using a scintillation detector, half-body detector, etc. In the detector, 2 is a preamplifier that amplifies the minute level electric pulse train signal output from the detector l, and 3 is a 100 liter amplifier 2.
This is a discriminator that removes noise contained in the output signal and shapes the signal's waveform. 4 is a pulse train signal 3P' output from the discriminator 3! This is a delay circuit that delays the time by a predetermined period of time.The reason why this circuit is provided will be described later. 4a is a pulse train signal output from the delay circuit.

tl is the time width of the pulse that forms this signal or the time width of the extractor 1
The radiation detection unit is composed of a preamplifier 2, a discriminator 3, and a delay circuit 4. Since each part of the radiation detection section 5 operates as described above, this detection section 5
This means that it is sensitive to both radiation, rays, and light, and outputs as a detection signal an electric pulse train signal 4a that corresponds to the incident mode of radiation or light. 6 is radiation incident on the detector 1;

7 is a pulse train generator that outputs a reference signal 7a which is an electric pulse train signal, and the reference signal 7a is a pulse with a time width t3 that is continuously outputted from the generator 7 with a period t (the time width is in %). t, and period t.

are respectively, for example, t, := 1 [μs), t
, = l (s). 20 is a pulse Ilk%' 4 VC where the signal 7a is input and the pulse width is smaller than t without changing the period t.
K 3'! In this case, for example, tt=Q, l[:μS].

Reference numeral 8 denotes a light emitter that is driven by the signal 20a and emits light to illuminate the detector 1 in response to pulses in the signal 20a. The detection 51 is rO, which is sensitive to light as described above, and if left as it is, will it be sensitive to external light other than the light emitted from the light emitter 8? ff11 for radiation 6
A measurement error occurs when determining the value. Therefore, although not shown, a lid for preventing the entrance of the extraneous light is provided at the radiation 60 incidence part of the detector 1, and the light emitter 8 is placed inside this space to irradiate the radiation @ 60 incidence part. is configured to do so. The pulse width of the pulsed light emitted from the light emitter 8 in response to the pulse in the signal 20a is equal to the above bar/L/7.
1. The width t is approximately equal to the width t, and the width 1. The relevant parts are constructed so that t is almost equal to t.

9 is a flip-flop in which when a pulse is input to the set terminal 9a, it becomes a set state and the output terminal 9C goes to L level; when a pulse is input to the reset terminal 9b, it becomes a reset state and the output terminal 9C goes to H level. 1 in the pull circuit
In the figure, the signal 20a is input to the terminal 9a.
A signal 4a is input to b. 10 is 7 lip 70
The output signal 9d of the tube circuit 9 and the reference signal 7a are input.

Output signal 10a is H only when both signals are at L level.
The signal tOa is input to the NOR circuit 11 which becomes the level,
This is a failure display circuit that displays the occurrence of a failure when this input signal goes to the H level, and continues to display the indication that the failure has occurred even if the signal tOa returns to the L level. The signals 4a and 7a are input to 12, and when the signal 7a is at L level, the signal 4a is passed through and the output signal 12 is sent to the input terminal 13H of the changeover switch 13.
a, and when signal 7a is at H level, signal 4a
I7') A gate circuit for blocking passage, 14 is an AND circuit into which signals 4a and 7a are input, and outputs an output signal 14a that becomes H level only when both input signals are at H level, and output signal 140 is Selector switch 13n input terminal 1
3blC input, output terminal 13C of selector switch 13
The signal output from the measuring section 15 is inputted to the measuring section 15. The measuring unit I5 is configured to count the pulses inputted through the terminal 13c and perform a predetermined measurement vJ for the radiation @6. 16 is a gate circuit 12 and an AND circuit 14
It is an arithmetic circuit consisting of.

Fig. 2 is an explanatory diagram of waveforms of the main parts in Fig. 1, the figure 0 is an explanatory diagram when the radiation detection unit 5 is operating normally, and the figure 0 is an explanatory diagram when a failure occurs in the detection unit 51C. It is a diagram.

Below, the radiation measurement device #CO operation shown in Figure 1 will be explained as follows.
This will be explained with reference to FIG. 1M42.

First, a case where no failure has occurred in the detection unit 5 will be described.

Detection g (!5 is configured as described above, so signal 7
a * 20 a changes to ICH rehe/I/ every time the period t elapses, and the light emitter 8 emits pulsed light of pulse @t4. The output signal 9d of the 7-lip 70-1 circuit becomes L level when No. 48 20a input to the set terminal 9a becomes H level, but at this time the reference signal 7a is still
-The output signal 10a of the NOR circuit is at J level (/')
is at L level.

When the detector 1 is irradiated with pulsed light as described above, the output signal 3a of the discriminator 3 is 1f'1
7It4 ”: Pulse boundary, this pulse is delayed circuit 4
The detection signal 4avc has a time width t equal to t4.
, n pulses appear. The rise time of this pulse in the signal 48 is delayed by a predetermined time τ than the rise time of the reference signal 7a due to the delay circuit 4 and the like. This pulse then falls to the L level for 1 hour while the reference signal 7a continues to be at the H level. ．． 14°τ is set. Signal 4a7! l″-
When the signal 9d goes to the H level, the signal 9d returns to the H level, and the signal 7a eventually goes to the L level at rO. In this case, the output signal lOa of the NOR circuit goes to the H level, and the failure indication circuit 11 performs a failure indication operation. There isn't. The signal 4a includes radiation 6 in addition to pulses from the light emitter 5rrt pulsed light.
VC, and when this pulse from the radiation 6 is input to the 7-lip, 10-tub circuit 9 within the time τ, the signal 9d returns to 1 level at this point, of course.

As described above, in the i-field where the reference signal 7a is at the L level, the gate circuit 12 allows the signal 4a to pass through, and the signal 7a
The gate circuit 12 is closed while a reaches the H level -C. Then, since the pulse caused by the pulsed light of the light emitter 8 included in the signal 41 is lost when the gate current circuit 12 is in the closed state, this pulse is not included in the output signal 12a of the circuit. Moreover, in this case 1. >>1. '
s/t! = L O-6. Therefore.

Switch to change the pulse in signal L2a! By counting by the measurement unit 15 via 3Q, the @aspiration of the radiation 6 can be measured within the range of permissible error. That is, signal 12a+! A measurement signal corresponding to the detection signal 4a outputted from the gate circuit I2 when the reference signal 7a is in the pulse extinction state is used by the % measuring section 15 to measure the radiation@GCO dose using this measurement signal L2a. Furthermore, since the signals 4a and 7a input to the AND circuit 14 each reach the I (level) over time as described above, the AND circuit (f) output signal 14a is a pulse train signal corresponding to the reference signal 7avc. Therefore, by inputting the signal L4a to the measuring section 15 via the changeover switch 13, 142
Even if pulses from the radiation 6 are mixed in the output signal 4a, the measurement unit 150 can be calibrated. That is, signal 14
A is a calibration signal that is output from the AND circuit 14 as a signal corresponding to the reference signal 73 when the reference signal 7a is in a pulse generation state, and can be used to calibrate the measurement section 15 using this signal 14a. In the arithmetic circuit 16 consisting of the gate circuit 12 and the AND circuit 14, each part operates on the 0 and vc axis as described above (/'JI, so in the end, the circuit 16 is
By performing a logical operation on the reference signal 7a and the detection signal 4a, when the reference signal 7a is in a pulse generation state, a calibration signal L4a corresponding to the reference signal 7a is output.

When the reference signal 7a is in a pulse extinction state, the detection signal 4a
This means that the circuit outputs the measurement signal L2a compatible with VC. In figure a1, the measurement o! i number L 2
a r: <: 1 nks input to constant section 15 1 calibration signal 1
4a is input to a measuring section to be calibrated (not shown) which is separate from the measuring section 15, while the measuring section 15vC measures 60 rays of radiation, the calibration signal 14a can calibrate the measuring section to be calibrated. You can do it.

The above-mentioned explanation was about the operation of each part when the radiation detection section 5 is normal, but first, a failure occurs in the radiation detection section 5, and as a result, the reference signal 7a becomes H level at time To. Assume that the signal 3aK is no longer outputted as a pulse. Then the time is 1゛.

The output signal 9d of the 770 tube circuit goes to L level, but the level of signal 4a never goes to H level. Therefore, at time T, both input values 9d and 7a of the NOR circuit 100 go to the L level (q), the output signal tOa goes to the H level, and the display circuit 11 breaks down. Display operation. That is, NOR circuit I
O is set to the H level σ) output signal 108 by a logical operation between the reference signal 7a and the output signal 9d of the 7-lip 70-tub circuit.
This is an arithmetic circuit that outputs as a failure signal. Therefore, the occurrence of a failure in the radiation detection section 5 can be known by the display operation of the display circuit 11. When such a failure occurs, the detection signal 4a will contain:

Neither the pulse caused by the radiation fivC nor the pulse caused by the pulsed light emitted from the light emitter 8 appears. Therefore, neither dose measurement using the measurement signal 12a nor calibration using the calibration signal 14a becomes possible.

Since each part of the radiation measuring device shown in FIG. 1 operates as described above, the failure of the radiation detection section 5 can be constantly monitored using the failure signal 10aK. Therefore, such a radiation measuring device is a measuring device that can check whether there is a failure rO in the detection section 5 without interrupting the measurement of the radiation to be measured Fi'')##.

Furthermore, in FIG. 1, as is clear from the above, the pulses in the detection signal 4a based on the pulsed light emitted from the light emitter 8 do not appear in the measurement signal 12a. Therefore, when measuring the low-level radiation 6, a phenomenon in which the measurement error exceeds the tolerance due to the light pulse emitted from the light emitter 8 does not occur.

Therefore, according to the vJ1 diagram, low-level radiation measurement is also r
Become an IT Noh. Furthermore, in the conventional third inspection method described above, a shuddering operation was performed on the output signal of the detector 1r shown in Fig. 1; No connection has been made.

Then, the measurement signal 12a and the calibration signal 14a are switched and input to the measurement section 15 corresponding to the signal processing section mentioned in the third inspection method at a stage subsequent to the M-position amplifier 2. ing. In the case of the late VC shown in FIG.
It is unplayable for a. Therefore, according to the measuring device shown in FIG. 1 (Ll), the inspection work for the 41 military unit 15 and the aforementioned side to be calibrated/military unit, etc. (not shown) becomes easy.

〔Effect of the invention〕

As described above, in the VC1 of the present invention, the radiation detection unit, which outputs a detection signal according to the incident radiation or source, is constantly forcibly irradiated with a light pulse train in the form of a reference pulse train, and the pulse train light drive is performed. By performing a logical operation using the electrical pulse train reference signal and the detection signal, #j! of the radiation is determined by the measurement signal corresponding to the detection signal and the definition signal. A calibration signal that serves as a reference for calibration work to the measurement unit that performs quantity measurement is always output, and a failure signal is automatically output when the radiation detection unit fails. The radiation measuring device can be operated without increasing the possible radiation level, without interrupting the measurement of the radiation to be measured, and without changing the transmission path of the minute signal output by the detector such as the scintillation detector. This has the effect of allowing inspection to be carried out. Furthermore, since the measurement signal and the calibration signal are constantly outputted in the present invention, the calibration of the rO measurement is performed separately from the measurement section that receives the measurement signal and measures the radiation dose.

There is also the effect that the line 111t measurement using the +tllll constant signal can be performed in parallel.

[Brief explanation of drawings]

Fig. 1 is a configuration diagram of an embodiment of the present invention, Fig. 2 is an explanatory diagram of waveforms of the main parts in Fig. 1, the figure 2 is an explanatory diagram when the radiation detection section is normal, and Radiation@detection part is defective19
It is an explanatory diagram when t. 4a...Detection signal, 5...Radiation detection section, 6...Radiation, 7...Pulse train generator, 7a...Reference point No.

Claims (1)

[Claims] a radiation detection unit that is sensitive to radiation and light and outputs a detection signal according to the incident radiation or light; and a pulse train generator that outputs a reference signal that is an electric pulse train in a predetermined manner. a light emitter that emits light based on the reference signal to irradiate the radiation detection unit; a flip-flop circuit that is set based on the reference signal and reset by the detection signal; a first arithmetic circuit that outputs a failure signal through a logical operation with the output signal of the flip-flop circuit; and a first arithmetic circuit that outputs a failure signal through a logical operation between the reference signal and the detection signal, and when the reference signal is in a pulse generation state, it corresponds to the reference signal. a second calibration signal, and outputs a measurement signal corresponding to the detection signal when the reference signal is in a pulse extinction state;
It is characterized by comprising an arithmetic circuit and a measurement unit that measures the radiation dose using the measurement signal, detects a failure in the radiation detection unit based on the failure signal, and calibrates the measurement unit using the calibration signal. Radiation measuring device.