JP5972601B2 - Radiation measuring device, electronic device and mobile phone terminal - Google Patents

Description

  The present invention relates to a radiation measuring apparatus for measuring a radiation dose by detecting radiation using a semiconductor element or the like.

  As a radiation measurement apparatus such as a radiation dose rate meter, a method using a semiconductor sensor is widely used. In this method, the radiation dose is measured by detecting current pulses excited by radiation incident on the semiconductor sensor. However, since the current pulse to be detected is weak, even if minute noise is mixed, noise may be erroneously detected without being distinguished from radiation.

  FIG. 19 is a block diagram showing a schematic configuration of a conventional radiation measurement apparatus 101. The radiation measurement apparatus 101 includes a radiation detection unit 102 and a radiation dose calculation unit 103. The radiation detection unit 102 detects the radiation and outputs a pulse to the radiation dose calculation unit 103. The radiation dose calculation unit 103 calculates the radiation dose detected by the radiation detection unit 102 based on the pulse.

  FIG. 20 is a block diagram illustrating a configuration of the radiation detection unit 102. The radiation detection unit 102 includes a radiation sensor 104, an amplifier 105, and a comparator 106. When radiation enters the radiation sensor 104, a weak current pulse is excited in the radiation sensor 104. The current pulse is amplified by the amplifier 105, and the amplified signal is input to the comparator 106. The comparator 106 compares the input signal with the threshold voltage, and outputs a pulse due to radiation when the voltage of the input signal is higher than the threshold voltage. The radiation dose calculation unit 103 counts the pulse output from the comparator 106 with a logic circuit, and calculates the radiation dose.

  However, since the current pulse to be detected is weak, even if a minute noise is mixed in the radiation detection unit 102, the radiation dose calculation unit 103 may detect the noise erroneously without being distinguished from the radiation. is there.

  On the other hand, in the following Patent Document 1, a method of increasing the radiation detection space volume and improving the sensitivity by connecting a plurality of semiconductor elements in parallel is shown.

Japanese Patent Laying-Open No. 2005-249483 (published on September 15, 2005)

  However, in the method disclosed in Patent Document 1, electrical noise is generated due to electromagnetic noise mixed in a semiconductor element, piezoelectric effect due to mechanical vibration, and stray capacitance change, and when this electrical noise and radiation are detected. There is a problem that there is a possibility that an electric pulse is mistaken.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to realize a radiation measuring apparatus capable of performing accurate measurement while eliminating the influence of noise.

In order to solve the above problems, a radiation measuring apparatus according to the present invention includes a radiation detector that detects radiation and outputs a pulse, and a radiation dose calculator that calculates a radiation dose by counting the pulses. a radiation measuring apparatus comprising, the radiation detection unit of the first and second outputs an electrical signal in response to the incidence of radiation and the radiation sensor, the output signal of the second radiation sensor in the first radiation A pulse output circuit unit for outputting the pulse when a value corresponding to a signal obtained by subtracting the output signal of the sensor is not within a range between a first value greater than 0 and a second value less than 0; It is characterized by providing.

  Normally, radiation is generated discretely in time and space, and therefore the first radiation sensor and the second radiation sensor have different timings for outputting electrical signals caused by radiation in the above configuration. Therefore, when radiation is incident on the radiation detection unit, the output of the first radiation sensor and the output of the second radiation sensor are in different phases, so the first radiation sensor is derived from the output signal of the second radiation sensor. The value obtained by subtracting the output signal is out of the range between the first value and the second value. Therefore, a pulse is output from the pulse output circuit unit.

  On the other hand, electrical noise generated by mechanical vibrations and external electromagnetic waves usually occurs simultaneously in the first and second radiation sensors. For this reason, when mechanical vibration or the like is applied to the radiation detection unit, the output of the first radiation sensor and the output of the second radiation sensor have the same phase. The value obtained by subtracting the output signal of the radiation sensor is within the range between the first value and the second value. Therefore, no pulse is output from the pulse output circuit unit.

  Therefore, it is possible to realize a radiation measurement apparatus that can perform accurate measurement while eliminating the influence of noise.

In radiation measurement device according to the present invention, the pulse output circuit includes a subtractor that outputs a voltage corresponding to the second subtraction signal of the output of the first radiation sensor from the output of the radiation sensor, the subtraction when the output voltage of the vessel is the first value or more, when the first comparator outputs a high-level pulse signal, the output voltage of the subtracter is equal to or less than the second value, a high level a second comparator which outputs a pulse signal, it is preferable that the logical sum of the output of said first comparator output and said second comparator and a OR gate circuit for outputting as said pulse.

  According to the above configuration, when radiation is incident on the radiation detection unit, the output of the first radiation sensor and the output of the second radiation sensor have different phases. Will fall outside the range between the second value and the second value. Therefore, a high-level pulse signal is output from either the first comparator or the second comparator, and a pulse is output from the OR gate circuit. Therefore, a pulse is output from the pulse output circuit unit.

  On the other hand, when mechanical vibration or the like is applied to the radiation detection unit, the output of the first radiation sensor and the output of the second radiation sensor are in the same phase. Is in a range between the value of and the second value. Therefore, neither the first comparator nor the second comparator outputs a high-level pulse signal, and no pulse is output from the OR gate circuit. Therefore, no pulse is output from the pulse output circuit unit.

In radiation measurement device according to the present invention, the pulse output circuit includes a second amplifier for amplifying a first amplifier for amplifying an output of the first radiation sensor, the output of the second radiation sensor, a subtractor for outputting a voltage obtained by subtracting the output voltage of the first amplifier from the output voltage of the second amplifier, the output voltage of the subtracter is, the gain of the second amplifier to said first value when it is multiplied by the value or more, a first comparator which outputs a high-level pulse signal, the output voltage of the subtracter is below the second value obtained by multiplying the gain of the first amplifier to the value in some cases, comprises a second comparator which outputs a high level pulse signal, and an OR gate circuit which outputs the logical sum of the output of said first comparator output and said second comparator as the pulse Door is preferable.

  According to the above configuration, when radiation is incident on the radiation detection unit, the output of the first amplifier and the output of the second amplifier have different phases, so the output voltage of the subtractor is the first value. And the value obtained by multiplying the gain of the second amplifier by the gain of the first amplifier and the value obtained by multiplying the second value by the gain of the first amplifier. Therefore, a high-level pulse signal is output from either the first comparator or the second comparator, and a pulse is output from the OR gate circuit. Therefore, a pulse is output from the pulse output circuit unit.

  On the other hand, when mechanical vibration or the like is applied to the radiation detection unit, the output of the first amplifier and the output of the second amplifier have the same phase, so the output voltage of the subtractor is the first value. Is in a range between a value obtained by multiplying the gain of the second amplifier by a value obtained by multiplying the second value by the gain of the first amplifier. Therefore, neither the first comparator nor the second comparator outputs a high-level pulse signal, and no pulse is output from the OR gate circuit. Therefore, no pulse is output from the pulse output circuit unit.

In radiation measurement device according to the present invention, the pulse output circuit includes a differential amplifier for amplifying and outputting the difference obtained by subtracting the output signal of the first radiation sensor from the output signal of the second radiation sensor, the output voltage of the differential amplifier, the case where the first value in the differential amplifier gain multiplied value or more, a first comparator which outputs a high level pulse signal, of the differential amplifier output voltage, if it is the following second value obtained by multiplying the gain of the differential amplifier to the value, a second comparator which outputs a high level pulse signal, said first comparator output and the first And an OR gate circuit that outputs a logical sum with the output of the two comparators as the pulse.

  According to the above configuration, when radiation is incident on the radiation detection unit, the output of the first radiation sensor and the output of the second radiation sensor have different phases. This is out of the range between a value obtained by multiplying the value of 1 by the gain of the differential amplifier and a value obtained by multiplying the second value by the gain of the differential amplifier. Therefore, a high-level pulse signal is output from either the first comparator or the second comparator, and a pulse is output from the OR gate circuit. Therefore, a pulse is output from the pulse output circuit unit.

  On the other hand, when mechanical vibration or the like is applied to the radiation detection unit, the output of the first radiation sensor and the output of the second radiation sensor are in the same phase. It falls within a range between a value obtained by multiplying the value of 1 by the gain of the differential amplifier and a value obtained by multiplying the second value by the gain of the differential amplifier. Therefore, neither the first comparator nor the second comparator outputs a high-level pulse signal, and no pulse is output from the OR gate circuit. Therefore, no pulse is output from the pulse output circuit unit.

In radiation measurement device according to the present invention may be an absolute value and are equal in the first value and the second value.

In radiation measurement device according to the present invention, the above-mentioned first radiation sensor and the second radiation sensors, that are symmetrically positioned within the radiation measurement device it is preferred.

  According to said structure, the mechanical vibration and electromagnetic wave given to the radiation measuring device have the same influence on a 1st radiation sensor and a 2nd radiation sensor. Therefore, when electrical noise is generated, in most cases, the output of the first radiation sensor and the output of the second radiation sensor have the same phase. Therefore, even if electrical noise occurs, it can be prevented with a very high probability that a pulse is output from the pulse output circuit unit.

  In the radiation measurement apparatus according to the present invention, the radiation dose calculation unit counts the pulses and outputs a total number of pulses counted within the measurement time, and calculates the radiation dose based on the total number. The radiation counting unit counts the pulses for each time slot having a certain time width, and when there is a time slot in which a predetermined number or more of pulses are counted, the time slot and its time slot are counted. The number of pulses counted in the preceding and following time slots is preferably not included in the total number.

  As described above, even if electrical noise occurs, it is possible to prevent a pulse from being output from the pulse output circuit unit with an extremely high probability. However, in rare cases, a pulse ( (Hereinafter referred to as “noise pulse”) may be output. Here, radiation pulses due to radiation tend to occur discretely, whereas noise pulses tend to occur intensively in a short time.

  Therefore, in the above configuration, when a predetermined number or more of pulses are counted in a certain time slot, the radiation counting unit ignores the number of pulses counted in the time slot and the time slots before and after the time slot. Since noise pulses tend to be generated intensively, it is possible to prevent the radiation counting unit from counting noise pulses and preventing the calculation result of the calculation unit from becoming inaccurate. Therefore, more accurate measurement is possible.

  In the radiation measurement apparatus according to the present invention, when the radiation detection unit detects the maximum amount of radiation that is assumed, the radiation pulse that is a pulse caused by radiation estimated from the Poisson distribution is included in one time slot. The time width is preferably set so that the probability that the predetermined number or more exists is equal to or less than the predetermined probability.

  It is known that the number of occurrences of radiation follows a Poisson distribution. Therefore, if the probability that the radiation pulse exists in one time slot is more than the predetermined number is estimated from the Poisson distribution and the time width of the time slot is set so that the probability is less than the predetermined probability, no noise pulse is generated. In addition, the probability that the predetermined number of pulses or more exist in one time slot can be set to the predetermined probability or less. Therefore, by setting the predetermined probability to a probability close to 0, the probability that the radiation pulse is not counted can be made extremely low, and more accurate measurement can be performed.

として、上記放射線量を補正することが好ましい。 In the radiation measurement apparatus according to the present invention, the calculation unit calculates the average occurrence rate λ per time slot when the average number of counted pulses per time slot calculated based on the total number is μ.

As described above, it is preferable to correct the radiation dose.

  When radiation pulses are included in pulses that are not counted due to generation of noise pulses, the calculated radiation dose is smaller than the actual radiation dose. On the other hand, according to said structure, since a radiation dose is correct | amended based on the probability that a radiation pulse is not contained in the said total, the calculation part can calculate a more exact radiation dose.

In the radiation measurement apparatus according to the present invention, the calculation unit includes, in the total number, the number of pulses counted in the time slot when it is assumed that the pulse is only a radiation pulse that is a pulse caused by radiation. A second ratio of the number of unsettled time slots to the total number of time slots in the measurement time, and the measurement time of the number of time slots in which the number of pulses counted in the time slot is not included in the total number a first ratio of the total number of time slots calculated in the inner, the if the third ratio of from a first rate by subtracting the second rate of greater than a predetermined value, to invalidate the calculated radiation dose Is preferred.

  According to the above configuration, the third ratio is equal to the ratio of the time slots in which the pulses are not counted due to the generation of the noise pulse to all the time slots. Therefore, when the third ratio is large, it can be predicted that the frequency of generation of noise pulses is high and the error of the count value of the radiation pulses is large. Therefore, when the third ratio is larger than the predetermined value, it is possible to prevent erroneous measurement by invalidating the calculated radiation dose.

In the radiation measurement apparatus according to the present invention, the calculation unit includes, in the total number, the number of pulses counted in the time slot when it is assumed that the pulse is only a radiation pulse that is a pulse caused by radiation. A second ratio of the number of unsettled time slots to the total number of time slots in the measurement time, and the measurement time of the number of time slots in which the number of pulses counted in the time slot is not included in the total number And the first rate relative to the total number of time slots within the time slot, and based on a third rate Q obtained by subtracting the second rate from the first rate , the average occurrence rate per time slot is 1 / ( 1-Q) times and be Rukoto is preferable.

  According to the above configuration, since the radiation dose is corrected based on the third ratio, which is the ratio of the time slots in which the pulses were not counted due to the generation of the noise pulse, the accuracy of the radiation measurement value is corrected. Can be further enhanced.

  In the radiation measuring apparatus according to the present invention, it is preferable that a plurality of the radiation detection units and the radiation counting units are provided.

  According to said structure, even if a noise pulse is output from either of several radiation detection parts, compared with the structure each provided with one radiation detection part and one radiation counting part, the influence of noise can further be reduced. it can.

  In the radiation measuring apparatus according to the present invention, the radiation sensor is preferably a semiconductor sensor.

  In the radiation measuring apparatus according to the present invention, the semiconductor sensor is preferably a PIN photodiode.

  According to said structure, a small and cheap radiation measuring device can be provided.

  In the radiation measuring apparatus according to the present invention, the semiconductor sensor preferably includes a scintillator and a photodiode.

  According to said structure, a more sensitive radiation measuring device can be provided.

  An electronic apparatus according to the present invention includes any one of the radiation measurement apparatuses described above.

  A mobile phone terminal according to the present invention includes any one of the radiation measurement apparatuses described above.

  As described above, the radiation measurement apparatus according to the present invention is a radiation measurement apparatus including a radiation detection unit that detects radiation and outputs a pulse, and a radiation dose calculation unit that calculates a radiation dose based on the pulse. The radiation detection unit includes first and second radiation sensors that output an electrical signal in response to radiation incidence, and a signal obtained by subtracting the output signal of the first radiation sensor from the output signal of the second radiation sensor. And a pulse output circuit unit that outputs the pulse when the value corresponding to is not within the range between the first value greater than 0 and the second value less than 0. Therefore, there is an effect that it is possible to realize a radiation measuring apparatus capable of performing accurate measurement by eliminating the influence of noise.

It is a block diagram showing an example of a radiation measuring device concerning a 1st embodiment of the present invention. It is a block diagram which shows the structure of the radiation detection part of the radiation measuring device shown in FIG. It is a figure which shows an example of the circuit response of a pulse output circuit part when a mechanical vibration is added to the radiation detection part shown in FIG. It is a block diagram which shows an example of the radiation detection part which concerns on the 2nd Embodiment of this invention. It is a block diagram which shows an example of the radiation detection part which concerns on the 3rd Embodiment of this invention. It is a top view which shows the structure of the radiation measuring device which concerns on the 4th Embodiment of this invention. It is a figure which shows an example of the circuit response of a pulse output circuit part when a mechanical vibration is added to the radiation detection part shown in FIG. It is a block diagram which shows the structure of the radiation measuring device which concerns on the 5th Embodiment of this invention. It is a figure for demonstrating the counting method of the pulse by the radiation counter of the radiation measuring device shown in FIG. It is a figure for demonstrating the counting method of the pulse by the said radiation counting part. It is a block diagram which shows the structural example of the said radiation counting part. It is a block diagram which shows the structure of the radiation measuring device which concerns on the 7th Embodiment of this invention. It is a block diagram which shows the structural example of the radiation counter of the radiation measuring device shown in FIG. It is a figure for demonstrating the counting method of the pulse by the radiation counter shown in FIG. It is a block diagram which shows an example of the radiation measuring device which concerns on the 9th Embodiment of this invention. It is a block diagram which shows an example of the radiation detection part using a PIN photodiode as a radiation sensor. It is a perspective view which shows the other example of a radiation sensor. It is a block diagram which shows the mobile telephone terminal which concerns on the 11th Embodiment of this invention. It is a block diagram which shows the structure of the conventional radiation measuring device. It is a block diagram which shows the structure of the radiation detection part of the radiation measuring device shown in FIG.

[First Embodiment]
The following describes the first embodiment of the present invention with reference to FIGS.

(Configuration of radiation measurement device)
FIG. 1 is a block diagram illustrating an example of a radiation measurement apparatus 1 according to the present embodiment. The radiation measurement apparatus 1 includes a radiation detection unit 2 and a radiation dose calculation unit 3.

  The radiation detection unit 2 includes two sets of radiation sensors 4 a and 4 b and a pulse output circuit unit 5, and functions as a radiation detector that detects radiation and outputs a pulse to the radiation dose calculation unit 3. The radiation dose calculation unit 3 calculates the radiation dose detected by the radiation detection unit 2 based on the pulse. The radiation dose calculation unit 3 has substantially the same configuration as the conventional radiation dose calculation unit 103 shown in FIG.

(Configuration of radiation detector)
FIG. 2 is a block diagram illustrating a configuration of the radiation detection unit 2. As described above, the radiation detection unit 2 includes two sets of radiation sensors 4 a and 4 b and the pulse output circuit unit 5. The pulse output circuit unit 5 includes a subtractor 6, two sets of comparators 7 a and 7 b, and an OR gate 8.

  The radiation sensor 4 a is connected to the negative input terminal of the subtractor 6, and the radiation sensor 4 b is connected to the positive input terminal of the subtractor 6. The output terminal of the subtractor 6 is connected to the positive input terminal of the comparator 7a and the negative input terminal of the comparator 7b.

  A positive threshold voltage Vth (first value) is input to the negative input terminal of the comparator 7a, and a negative threshold voltage −Vth (second value) is input to the positive input terminal of the comparator 7b. The Each output terminal of the comparators 7 a and 7 b is connected to an input terminal of the OR gate 8.

  In the above configuration, when radiation enters the radiation sensors 4a and 4b, the radiation sensors 4a and 4b output electrical signals (current pulses). The subtractor 6 outputs a voltage signal corresponding to a signal obtained by subtracting the output signal of the radiation sensor 4a from the output signal of the radiation sensor 4b.

  The comparator 7a outputs a high level pulse signal when the output voltage of the subtractor 6 is equal to or higher than Vth. Further, the comparator 7b outputs a high-level pulse signal when the output voltage of the subtractor 6 is −Vth or less. The OR gate 8 outputs a logical sum of the output of the comparator 7a and the output of the comparator 7b as a pulse signal. The output signal of the OR gate 8 becomes the output of the pulse output circuit unit 5.

  As described above, the pulse output circuit unit 5 outputs a pulse when the voltage value corresponding to the signal obtained by subtracting the output signal of the radiation sensor 4a from the output signal of the radiation sensor 4b is not within the range between Vth and -Vth. Is output.

(When radiation is incident)
Usually, since radiation is generated discretely in time and space, the radiation sensor 4a and the radiation sensor 4b have different timings for outputting electrical signals due to radiation.

  Therefore, as shown in FIG. 2, when radiation sequentially enters the radiation sensors 4 a and 4 b, signals are input to the negative input terminal and the positive input terminal of the subtractor 6 at different timings. A signal having two different peaks is output. When the peak voltage is equal to or higher than Vth or equal to or lower than −Vth, one pulse is output from each of the comparators 7a and 7b. These pulses are integrated in the OR gate 8, and two pulses are output from the OR gate 8.

(When electrical noise occurs)
On the other hand, electrical noise generated by mechanical vibration or external electromagnetic waves is usually generated simultaneously in the radiation sensors 4a and 4b.

  For example, as shown in FIG. 3, when electrical noise due to mechanical vibration is simultaneously generated in the radiation sensors 4a and 4b, signals having the same waveform are input to the negative input terminal and the positive input terminal of the subtractor 6, respectively. . Therefore, these signals are canceled by the subtractor 6, and the output voltage of the subtractor 6 does not become Vth or higher or −Vth or lower. Therefore, no pulse is output from the OR gate 8.

(Summary)
As described above, the radiation measurement apparatus 1 according to the present embodiment includes a radiation detection unit 2 that detects radiation and outputs a pulse, and a radiation dose calculation unit 3 that calculates a radiation dose based on the pulse. In the measurement apparatus, the radiation detection unit 2 corresponds to radiation sensors 4a and 4b that output electrical signals in response to the incidence of radiation, and a signal obtained by subtracting the output signal of the radiation sensor 4a from the output signal of the radiation sensor 4b. When the voltage value is not within the range between Vth and -Vth, the pulse output circuit unit 5 outputs the pulse.

  In this configuration, when radiation is incident on the radiation detector 2, the timing at which electrical signals are output from the radiation sensors 4a and 4b is usually different. Therefore, the probability that these signals are canceled in the subtractor 6 is extremely low, and pulses corresponding to the outputs from the radiation sensors 4a and 4b are output from the OR gate 8. On the other hand, when electrical noise due to mechanical vibration or external electromagnetic waves is generated in the radiation sensors 4a and 4b, signals of the same waveform are output from the radiation sensors 4a and 4b, and these signals are canceled by the subtractor 6. Thus, no pulse is output from the OR gate 8.

  Therefore, it is possible to realize a radiation measurement apparatus that can perform accurate measurement while eliminating the influence of noise.

  Note that the absolute values of the threshold voltage Vth and the threshold voltage −Vth may be different or the same.

[Second Embodiment]
The following describes the second embodiment of the present invention with reference to FIG. In the present embodiment, another configuration example of the radiation detection unit will be described.

(Configuration of radiation detector)
FIG. 4 is a block diagram illustrating a configuration of the radiation detection unit 12 according to the present embodiment. The radiation detection unit 12 includes two sets of radiation sensors 4 a and 4 b and a pulse output circuit unit 15. The pulse output circuit unit 15 includes a subtractor 6, two sets of comparators 7a and 7b, an OR gate 8, and two sets of amplifiers 9a and 9b.

  The radiation sensor 4a is connected to the negative input terminal of the subtractor 6 via the amplifier 9a, and the radiation sensor 4b is connected to the positive input terminal of the subtractor 6 via the amplifier 9b. The radiation sensor 4a and the amplifier 9a constitute a front end portion 10a, and the radiation sensor 4b and the amplifier 9b constitute a front end portion 10b. The gain of the amplifier 9a is Ga, and the gain of the amplifier 9b is Gb. Ga and Gb may be different or equal. The output terminal of the subtractor 6 is connected to the positive input terminal of the comparator 7a and the negative input terminal of the comparator 7b.

  A voltage having a value obtained by multiplying the threshold voltage Vth by Gb is input to the negative input terminal of the comparator 7a, and a voltage having a value obtained by multiplying the threshold voltage −Vth by Ga is input to the positive input terminal of the comparator 7b. Entered. Each output terminal of the comparators 7 a and 7 b is connected to an input terminal of the OR gate 8.

(Operation of radiation detector)
In the above configuration, when radiation enters the radiation sensors 4a and 4b, the radiation sensors 4a and 4b output electrical signals (current pulses). The amplifier 9a amplifies the output of the radiation sensor 4a and outputs it to the negative input terminal of the subtractor 6. The amplifier 9b amplifies the output of the radiation sensor 4b and outputs it to the positive input terminal of the subtractor 6. The subtractor 6 outputs a signal obtained by subtracting the output voltage of the amplifier 9a from the output voltage of the amplifier 9b.

  The comparator 7a outputs a high-level pulse signal when the output voltage of the subtractor 6 is Vth × Gb or more. The comparator 7b outputs a high-level pulse signal when the output voltage of the subtractor 6 is −Vth × Ga or less. The OR gate 8 outputs a logical sum of the output of the comparator 7a and the output of the comparator 7b as a pulse signal. The output signal of the OR gate 8 becomes the output of the pulse output circuit unit 15.

  As described above, the pulse output circuit unit 15 has a voltage value corresponding to a signal obtained by subtracting the output signal of the radiation sensor 4a from the output signal of the radiation sensor 4b, similarly to the pulse output circuit unit 5 according to the first embodiment. , Vth and −Vth are not within the range, a pulse is output.

  Therefore, as described in the first embodiment, when radiation enters the radiation detection unit 12, the timing at which electrical signals are output from the radiation sensors 4a and 4b is usually different. Therefore, the probability that each output signal from the amplifiers 9a and 9b is canceled in the subtractor 6 is extremely low, and a pulse corresponding to each output from the radiation sensors 4a and 4b is output from the OR gate 8. On the other hand, when electrical noise due to mechanical vibration or external electromagnetic waves is generated in the radiation sensors 4a and 4b, signals of the same waveform are output from the radiation sensors 4a and 4b, so that each output signal from the amplifiers 9a and 9b. Are canceled in the subtractor 6, and no pulse is output from the OR gate 8.

  Therefore, it is possible to realize a radiation measurement apparatus that can perform accurate measurement while eliminating the influence of noise.

  In the present embodiment, the current signals generated by the radiation sensors 4a and 4b are amplified by the amplifiers 9a and 9b and input to the subtractor 6, so that the current signals generated by the radiation sensors 4a and 4b are weak. However, it is possible to detect radiation with high accuracy.

[Third Embodiment]
The following describes the third embodiment of the present invention with reference to FIG. In the present embodiment, still another configuration example of the radiation detection unit will be described.

(Configuration of radiation detector)
FIG. 5 is a block diagram illustrating a configuration of the radiation detection unit 22 according to the present embodiment. The radiation detection unit 22 includes two sets of radiation sensors 4 a and 4 b and a pulse output circuit unit 25. The pulse output circuit unit 25 includes a differential amplifier 26, two sets of comparators 7a and 7b, an OR gate 8, and two sets of amplifiers 9a and 9b.

  The radiation sensor 4 a is connected to the negative input terminal of the differential amplifier 26, and the radiation sensor 4 b is connected to the positive input terminal of the differential amplifier 26. The gain of the differential amplifier 26 is G. The output terminal of the differential amplifier 26 is connected to the positive input terminal of the comparator 7a and the negative input terminal of the comparator 7b.

  A voltage having a value obtained by multiplying the threshold voltage Vth by G is input to the negative input terminal of the comparator 7a, and a voltage having a value obtained by multiplying the threshold voltage −Vth by G is input to the positive input terminal of the comparator 7b. Is done. Each output terminal of the comparators 7 a and 7 b is connected to an input terminal of the OR gate 8.

(Operation of radiation detector)
In the above configuration, when radiation enters the radiation sensors 4a and 4b, the radiation sensors 4a and 4b output electrical signals (current pulses). The differential amplifier 26 amplifies and outputs the difference obtained by subtracting the output signal of the radiation sensor 4a from the output signal of the radiation sensor 4b.

  The comparator 7a outputs a high-level pulse signal when the output voltage of the differential amplifier 26 is equal to or higher than Vth × G. The comparator 7b outputs a high-level pulse signal when the output voltage of the differential amplifier 26 is −Vth × G or less. The OR gate 8 outputs a logical sum of the output of the comparator 7a and the output of the comparator 7b as a pulse signal. An output signal of the OR gate 8 becomes an output of the pulse output circuit unit 25.

  As described above, the pulse output circuit unit 25 has a voltage value corresponding to a signal obtained by subtracting the output signal of the radiation sensor 4a from the output signal of the radiation sensor 4b, similarly to the pulse output circuit unit 5 according to the first embodiment. , Vth and −Vth are not within the range, a pulse is output.

  Therefore, as described in the first embodiment, when radiation is incident on the radiation detection unit 22, the timings at which electrical signals are output from the radiation sensors 4a and 4b are usually different. Therefore, the probability that these signals are canceled in the differential amplifier 26 is very low, and pulses corresponding to the outputs from the radiation sensors 4a and 4b are output from the OR gate 8. On the other hand, when electrical noise due to mechanical vibration or external electromagnetic waves is generated in the radiation sensors 4a and 4b, signals of the same waveform are output from the radiation sensors 4a and 4b. Canceled and no pulse is output from the OR gate 8.

  Therefore, it is possible to realize a radiation measurement apparatus that can perform accurate measurement while eliminating the influence of noise.

  In this embodiment, since the difference between the current signals generated by the radiation sensors 4a and 4b is amplified by the differential amplifier 26, even if the current signals generated by the radiation sensors 4a and 4b are weak, the radiation is accurately obtained. Can be detected.

[Fourth Embodiment]
The following describes the fourth embodiment of the present invention with reference to FIG. In the present embodiment, component arrangement of the radiation measuring apparatus will be described.

  FIG. 6 is a plan view showing the configuration of the radiation measuring apparatus 1a according to the present embodiment. The radiation measuring apparatus 1a is obtained by replacing the pulse output circuit unit 5 in the radiation measuring apparatus 1 shown in FIG. 1 with a pulse output circuit unit 25 shown in FIG. The components of the radiation measuring apparatus 1a are mounted on the circuit board 20. Specifically, the radiation measurement apparatus 1a is configured by mounting the radiation sensors 4a and 4b, the differential amplifier 26, the comparators 7a and 7b, and the logic circuit 28 on the circuit board 20. The logic circuit 28 corresponds to the OR gate 8 shown in FIG. 5 and the radiation dose calculator 3 shown in FIG.

  The radiation sensors 4a and 4b, the differential amplifier 26, the comparators 7a and 7b, and the logic circuit 28 are arranged symmetrically with respect to an alternate long and short dash line that divides the circuit board 20 into two equal parts. That is, the radiation sensor 4a and the radiation sensor 4b are arranged symmetrically in the radiation measuring apparatus 1a, and the output of the radiation sensor 4a and the output of the radiation sensor 4b are different differential inputs of the differential amplifier 26. Input to the terminal.

  Thus, by arranging the radiation sensor 4a and the radiation sensor 4b so as to be mechanically and electrically equivalent, the mechanical vibration and electromagnetic wave applied to the radiation measuring apparatus 1a are applied to the radiation sensor 4a and the radiation sensor. 4b is equally affected. Thus, when electrical noise is generated, in most cases, signals having the same phase are input to the two differential input terminals of the differential amplifier 26, and these signals are canceled by the differential amplifier 26.

[Fifth Embodiment]
The following describes the fifth embodiment of the present invention with reference to FIGS. In each of the above-described embodiments, the configuration has been described in which, when electrical noise occurs, the influence of noise is eliminated by canceling the electrical noise in the subtractor or differential amplifier of the radiation detection unit. However, in practice, not all electrical noise can be canceled by the radiation detection unit, and in rare cases, pulses (hereinafter referred to as “noise pulses”) resulting from electrical noise are output from the radiation detection unit. There is a case.

  For example, when mechanical vibration is locally applied to the radiation measurement apparatus 1, the phases of the electrical signals from the two radiation sensors may be shifted. Specifically, in the radiation detection unit 22 shown in FIG. 7, when mechanical vibration is applied at a position close to one radiation sensor 4a, the phase of the electrical signal generated by the radiation sensor 4b is generated by the radiation sensor 4a. It will be delayed from the phase of the electrical signal. Therefore, the differential amplifier 26 cannot cancel each signal from the radiation sensors 4a and 4b, and a noise pulse is output from the radiation detection unit 22 (OR gate 8).

  Further, even when the arrangement of the two radiation sensors 4a and 4b is not mechanically and electrically equivalent, a difference occurs in propagation of mechanical vibration. Therefore, there is a high possibility that a difference occurs in the phase of each electric signal generated from the radiation sensors 4a and 4b due to mechanical vibration, and that the signal cannot be effectively canceled by the differential amplifier 26.

  Therefore, in the present embodiment, a configuration that enables accurate measurement even when a noise pulse is output from the radiation detection unit will be described.

(Configuration of radiation measurement device)
FIG. 8 is a block diagram showing a configuration of the radiation measurement apparatus 11 according to the present embodiment. The radiation measurement apparatus 11 includes a radiation detection unit 22 and a radiation calculation unit 13.

  Since the configuration of the radiation detection unit 22 is the same as that shown in FIGS. 5 and 7, the description thereof is omitted.

  The radiation calculation unit 13 includes a radiation counting unit 30 and a calculation unit 40.

  The radiation counter 30 counts the pulses from the radiation detector 22 and outputs the total number of pulses counted within the measurement time (hereinafter referred to as “pulse count number”), as shown in FIG. In addition, the pulses output from the radiation detection unit 22 are counted for each time slot (hereinafter, referred to as “slot”) having a certain time width. The radiation counting unit 30 outputs data indicating the processing slot number and the pulse count number to the calculating unit 40.

  The calculation unit 40 calculates the radiation dose incident on the radiation sensors 4a and 4b within the measurement time based on the data from the radiation counting unit 30. The calculation unit 40 can be realized as software of a personal computer, for example.

  It is known that radiation tends to be generated spatially and temporally discretely, and the number of occurrences of radiation follows a Poisson distribution. Specifically, when the number of pulses caused by radiation (hereinafter referred to as “radiation pulses”) is counted for each slot having a certain time width, The probability P that the number of pulses X generated in the slot is k is

Given in. As an example, Table 1 shows probability distributions for several λ.

  If a slot width is selected so that λ becomes sufficiently small, the radiation pulse can be measured with accuracy with no practical problem even if only the radiation pulse generated alone in the target slot is counted as shown in FIG.

  That is, when the radiation detection unit 22 detects the maximum amount of radiation that is assumed, the slot estimated so that the probability that a predetermined number or more of radiation pulses exist in one slot is less than or equal to the predetermined probability is estimated from the Poisson distribution. Is set. If the time width of the slot is set in this way, when no noise pulse is generated, the probability that the predetermined number of pulses or more exist in one time slot can be set to the predetermined probability or less. For example, when the predetermined number is 2 and the predetermined probability is 0.001 or less, when the radiation detection unit 22 detects the maximum amount of radiation assumed, λ is 0.0500 or less. Set the time width as follows. Thus, the probability that the radiation pulse is not counted can be reduced by setting the predetermined probability to a probability close to zero.

(Exclude noise pulses)
As described above, the radiation detection unit 22 may output a noise pulse in addition to the radiation pulse.

  On the other hand, when there is a slot in which a predetermined number (2 in this embodiment) or more of pulses are counted, the radiation counting unit 30 calculates the number of pulses counted in the slot and the slots before and after the slot. It is configured not to be included in the number (excluded from the sum of the counts). Specifically, as shown in FIG. 10, if a plurality of pulses are generated in the target slot, the count values of the target slot and the front and rear slots of the target slot are ignored.

  While radiation tends to occur discretely, noise pulses tend to occur intensively in a short time. Therefore, when a plurality of pulses are generated in the target slot, it is possible to prevent the noise pulse from being counted by ignoring the count values of the target slot and the front and rear slots of the target slot. .

(Configuration example of radiation counting unit 30)
A counting algorithm for realizing the above processing will be described with reference to FIG. FIG. 11 is a block diagram illustrating a configuration example of the radiation counting unit 30. The radiation counting unit 30 includes an Ns counter 31, a demultiplexer 32, a 2-bit counter 33 (0) / 33 (1) / 33 (2), a determination circuit unit 34, and an Nc counter 35.

  The Ns counter 31 receives a clock having a period of the slot time width. The Ns counter 31 counts the number of clocks, thereby counting the number of processing slots Ns within the measurement time (hereinafter referred to as “number of processing slots Ns”). The processing slot number Ns is output to the demultiplexer 32 and the calculation unit 40 shown in FIG.

  The demultiplexer 32 inputs the pulse output from the radiation detection unit 22 to one of the three counters 33 (0), 33 (1), and 33 (2) based on the processing slot number Ns. Specifically, the demultiplexer 32 selects the counter 33 (0) when Ns = 3n (n is an integer), and selects the counter 33 (1) when Ns = 3n + 1, and Ns = 3n + 2 If so, the counter 33 (2) is selected. That is, the pulse count value of the Nsth processing slot is stored in the counter 33 (Ns mod 3). Ns mod 3 indicates a remainder obtained by dividing Ns by 3, and 0 ≦ Ns mod 3 ≦ 2. However, when three or more pulses are generated in one processing slot, the pulse count value of the processing slot is set to 3 regardless of the number of pulses.

  As a result, the counters 33 (0), 33 (1), and 33 (2) store the pulse count values of the processing target slot and the slots before and after it at each time, respectively.

Based on the values stored in the respective counters 33 (0), 33 (1), and 33 (2), the determination circuit unit 34 calculates the pulse count value of the processing target slot to the pulse count number that is output to the calculation unit 40. It is a logic circuit that determines whether or not to add. After the processing of the (Ns + 1) th slot is completed, the determination circuit unit 34 determines whether or not to add the pulse count value of the Nsth slot to the measurement value. Specifically, the determination circuit unit 34
[Count value of counter 33 (Ns mod 3) = 1] ∧ [Count value of counter 33 (Ns−1 mod 3) ≦ 1] ∧ [Count value of counter 33 (Ns + 1 mod 3) ≦ 1]
Only when is satisfied, a high-level pulse signal is output to the Nc counter 35. As a result, the Nc counter 35 increases the number of pulse counts output to the calculation unit 40 by one.

  With the above processing, noise pulses can be excluded from the pulse count number output from the radiation counter 30 to the calculator 40 shown in FIG. As described above, the radiation measuring apparatus 11 measures the noise due to mechanical vibration, electromagnetic waves, and the like because the radiation counting unit 30 ignores the noise pulse even when the electrical noise cannot be canceled by the radiation detecting unit 22. Inaccurate results can be prevented. Therefore, the measurement accuracy can be further increased.

  If the time width of the slot is made too short, the probability that two or more noise pulses are present in one slot is reduced when a noise pulse is generated. That is, since the probability that only one noise pulse exists in one slot increases, there is a high possibility that the noise pulses will be counted even if the noise pulse is generated.

[Sixth Embodiment]
The sixth embodiment of the present invention will be described as follows. In the processing in the fifth embodiment described above, the radiation pulses that should be counted are also excluded from the counting with a certain probability. Therefore, in the sixth embodiment, it is possible to perform more accurate measurement by estimating the probability of leakage (probability that the radiation pulse is not included in the pulse count number) and correcting the radiation dose based on the probability. Yes.

  When the process of the fifth embodiment is performed under a radiation dose condition where the average count number per slot is λ (that is, a condition in which the probability distribution satisfies the following formula 2), two or more pulses are observed. Pulses generated in the slot and the slots before and after it are excluded from the count.

Therefore, the expected value μ of the average count value when counting over a long time is
μ = P (X = 1) × {P (X = 0) + P (X = 1)} ²
It is a value calculated by. This is the probability that the pulse observation value of the slot to be counted is 1 and the pulse observation values of the preceding and following slots are 0 or 1. When μ is calculated for different values of λ, the expected value (1−μ / λ) of the loss rate due to the removal of the radiation pulses that should be counted by the process according to the fifth embodiment is shown in Table 2. become that way.

It can be seen from Table 2 that λ is an appropriate approximation of the expected loss rate. Therefore,
λ = 1-μ / λ
And solving for λ under the condition of μ <0.25,

It becomes. By using λ obtained by Equation 3 as the average incidence rate per slot of the radiation pulse, it is possible to obtain a measurement value in which the loss is corrected.

[Seventh Embodiment]
The seventh embodiment of the present invention will be described below with reference to FIGS. For convenience of explanation, members having the same functions as those described in the above embodiments are denoted by the same reference numerals and description thereof is omitted.

(Configuration of radiation measurement device)
FIG. 12 is a block diagram illustrating an example of the radiation measurement apparatus 11a according to the present embodiment. The radiation measurement apparatus 11a includes a radiation detection unit 22 and a radiation dose calculation unit 13a, and the radiation dose calculation unit 13a includes a radiation counting unit 30a and a calculation unit 40a. The radiation counter 30a is configured to further output the number of removal slots in addition to the number of processing slots and the number of pulse counts. The number of removed slots means the number of slots in which the pulse is excluded from the measurement even though the pulse is generated during the actual measurement.

(Configuration of radiation counter)
FIG. 13 is a block diagram illustrating a configuration example of the radiation counting unit 30a. The radiation counting unit 30 a includes an Ns counter 31, a demultiplexer 32, a 2-bit counter 33 (0) / 33 (1) / 33 (2), a determination circuit unit 34, an Nc counter 35, a determination circuit unit 36, and an Nd counter 37. It has. That is, the radiation counting unit 30a is configured to further include a determination circuit unit 36 and an Nd counter 37 in the radiation counting unit 30 shown in FIG.

Based on the values stored in the counters 33 (0), 33 (1), and 33 (2), the determination circuit unit 36 excludes the pulses from the measurement even though the pulses are generated during actual measurement. This is a logic circuit for determining the presence or absence of a removal slot. After the processing of the Ns + 1th slot is completed, the determination circuit unit 36
[2 ≦ count value of counter 33 (Ns mod 3)] ∨ [(1 ≦ count value of counter 33 (Ns mod 3)) ∧ {(2 ≦ count value of counter 33 (Ns−1 mod 3)) ∨ ( 2 ≦ counter 33 (count value of Ns + 1 mod 3)}]
Only when is satisfied, a high-level pulse signal is output to the Nd counter 37. As a result, the Nd counter 37 increases the number of removed slots Nd output to the calculation unit 40a by one.

  The calculation unit 40a illustrated in FIG. 12 calculates the radiation dose based on the number of processing slots, the number of pulse counts, and the number of removal slots input from the radiation counting unit 30a. Specifically, the calculation unit 40a performs the following processing.

(Processing of calculation part)
As shown in FIG. 14, when the slots to be removed for noise removal include the radiation pulses that should be counted, the count number becomes smaller (loss) than the actual number of radiation pulses. First, when there is no noise pulse, a ratio (second ratio) D (λ) at which the slot in which the pulse is generated is ignored is as follows.
D (λ) = P (X> 1) + P (X = 1) {2P (X> 1) −P (X> 1) ² }
It becomes. Further, D (λ) is obtained as shown in Table 3 for different values of λ.

  Subsequently, the calculation unit 40a obtains the number of removal slots Nd from the radiation counting unit 30a, and the slot removal rate E (= Nd /) which is the ratio (first ratio) of the number of removal slots Nd to the total number of processing slots Ns. Ns). If the slot removal rate E is larger than D (λ), it is estimated that the slot is excluded from the measurement due to the noise pulse. Therefore, the ratio (third ratio) Q at which the slot is excluded from the measurement due to the noise pulse is calculated by Q = ED (λ).

  Here, since the generation of the noise pulse and the generation of the radiation pulse are uncorrelated, it is estimated that the loss rate of the radiation pulse due to the slot removal is equal to the ratio Q. Therefore, when the ratio Q is large, it can be predicted that the frequency of occurrence of noise pulses is high and the error of the count value of radiation pulses is large.

Therefore, the calculation unit 40a uses the ratio Q as an index for determining the reliability of the count value. For example, when the ratio Q in a certain measurement period is larger than a predetermined value (for example, 0.01), the calculation unit 40a invalidates the measurement because the count result of the radiation pulse in that period is not reliable. In other words, the calculation unit 40a assumes that the number of pulses counted in the slot is not included in the pulse count number, and the total number of slots within the measurement time when the pulse is assumed to be only a radiation pulse. the second ratio of for (D (λ)) and the first proportion of the total number of slots in the number of measurement times of the number of counted in the slot pulse is not included in the pulse count slot (E) When the third ratio (Q) obtained by subtracting the second ratio from the first ratio is larger than a predetermined value, the calculated radiation dose is invalidated.

  This can prevent erroneous measurement.

[Eighth Embodiment]
The following describes the eighth embodiment of the present invention. In the present embodiment, the radiation dose is corrected using the ratio Q obtained in the seventh embodiment. That is, it is possible to obtain a more accurate radiation measurement value by predicting the probability that the radiation pulse that should be counted is leaked from the count.

  Specifically, the count ν per slot with the loss corrected is approximately obtained by ν = λ / (1−Q). By using this value as the average incidence rate per slot of the radiation pulse, the accuracy of the radiation measurement value can be further increased.

[Ninth Embodiment]
The ninth embodiment of the present invention will be described below with reference to FIG.

  FIG. 15 is a block diagram illustrating an example of the radiation measurement apparatus 11b according to the present embodiment. The radiation measuring apparatus 11b includes three radiation detection units 22 and a radiation dose calculation unit 13b, and the radiation dose calculation unit 13b includes three radiation counting units 30 and a calculation unit 40b. That is, the radiation measuring apparatus 11b is configured to include the radiation detecting unit 22 and the radiation counting unit 30 described in the fifth embodiment. The calculation unit 40b measures the radiation dose by adding the input data from each radiation counting unit 30 and performing the calculation substantially the same as in each of the above-described embodiments.

  In this way, by providing a plurality of radiation detectors 22 and radiation counters 30, even if a noise pulse is output from any of the radiation detectors 22, the effect of the noise pulses is greater than in each of the embodiments described above. Can be reduced.

  Furthermore, it is desirable that the radiation detectors 22 be provided apart from each other. Thereby, since all the radiation detection parts 22 can reduce the probability of receiving the influence of the noise by mechanical vibration, electromagnetic waves, etc., it becomes possible to implement | achieve a radiation measurement apparatus with higher precision.

[Tenth embodiment]
The tenth embodiment of the present invention will be described below with reference to FIGS. In this embodiment, an example of a semiconductor sensor suitably used for a radiation sensor will be described.

  FIG. 16 shows a radiation detection unit 22 that uses PIN photodiodes 14a and 14b as radiation sensors. A bias voltage Vbias is applied to each cathode of the PIN photodiodes 14a and 14b. The anode of the PIN photodiode 14 a is connected to the negative input terminal of the differential amplifier 26, and the anode of the PIN photodiode 14 b is connected to the positive input terminal of the differential amplifier 26.

  The depletion layer between the electrodes is expanded by putting the PIN photodiodes 14a and 14b in a reverse bias state. When radiation enters the depletion layer, electron hole pairs are generated by the ionization action, and are collected by a reverse bias electric field, and a current flows through the PIN photodiodes 14a and 14b.

  Thus, by using a PIN photodiode as a radiation sensor, a small and inexpensive radiation measuring apparatus can be provided.

  FIG. 17 shows the radiation sensor 24. The radiation sensor 24 includes a scintillator 24a that converts radiation into light, and a photodiode 24b that converts light generated from the scintillator 24a into an electrical signal. By setting the radiation sensor to such a structure, it is possible to provide a radiation measuring apparatus with higher sensitivity.

[Eleventh embodiment]
The following describes the eleventh embodiment of the present invention with reference to FIG.

  FIG. 18 is a block diagram showing the mobile phone terminal 41 according to the present embodiment. The mobile phone terminal 41 includes a communication device 42, a display device 43, and a radiation measurement device 44.

  The communication device 42 has a function for the mobile phone terminal 41 to perform a call with another mobile phone terminal, send / receive mail, and the like.

  As the display device 43, a liquid crystal display or the like is preferably used in order to form the mobile phone terminal 41 thin.

  As the radiation measurement device 44, any of the radiation measurement devices 1, 1a, 11, 11a, and 11b described in the above embodiment is used. The measurement result of the radiation measuring device 44 is displayed on the display device 43. Further, using the communication device 42, data of measurement results of the radiation measuring device 44 can be transferred to another electronic device.

  As described above, by mounting the radiation measuring apparatus according to the embodiment of the present invention on the mobile phone terminal, the display unit of the mobile phone terminal is used for displaying the radiation measurement result, or the measurement result is transferred by the communication function. It becomes possible.

  Note that the radiation measuring apparatus according to the embodiment of the present invention can be mounted on any electronic device other than the mobile phone terminal.

[Additional Notes]
The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope shown in the claims, and embodiments obtained by appropriately combining technical means disclosed in different embodiments. Is also included in the technical scope of the present invention.

  The present invention can also be expressed as follows.

  The radiation measurement apparatus according to the present invention includes two sets of circuits in which the output of the radiation sensor is connected to the input of an amplifier, a subtractor that subtracts those outputs, and a comparator that compares the output with a threshold voltage. It is characterized by detecting radiation.

  The radiation measuring apparatus according to the present invention is preferably provided by connecting two sets of radiation sensors to the positive and negative inputs of the differential amplifier, respectively, and detecting radiation.

  The radiation measuring apparatus according to the present invention preferably uses a semiconductor element as a radiation sensor.

  The radiation measuring apparatus according to the present invention preferably uses a combination of a scintillator and a semiconductor element as a radiation sensor.

  The radiation measuring apparatus according to the present invention is preferably arranged so that the two sets of radiation sensors are mechanically and electrically equivalent.

  It is preferable that the radiation measuring apparatus according to the present invention excludes temporally close pulses from the count.

  A mobile phone terminal according to the present invention incorporates any of the radiation measurement apparatuses described above.

  The present invention can be used for an electronic circuit and an electronic device for detecting a radiation dose.

DESCRIPTION OF SYMBOLS 1 Radiation measuring device 1a Radiation measuring device 2 Radiation detection part 3 Radiation dose calculation part 4a Radiation sensor (1st radiation sensor)
4b Radiation sensor (second radiation sensor)
5 Pulse output circuit section 6 Subtractor 7a Comparator (first comparator)
7b Comparator (second comparator)
8 OR gate 9a Amplifier (first amplifier)
9b Amplifier (second amplifier)
DESCRIPTION OF SYMBOLS 10a Front end part 10b Front end part 11 Radiation measurement apparatus 11a Radiation measurement apparatus 11b Radiation measurement apparatus 12 Radiation detection part 13 Radiation calculation part 13a Radiation dose calculation part 13b Radiation dose calculation part 14a PIN photodiode 14b PIN photodiode 15 Pulse output circuit Unit 20 circuit board 22 radiation detection unit 24 radiation sensor 24a scintillator 24b photodiode 25 pulse output circuit unit 26 differential amplifier 28 logic circuit 30 radiation counting unit 30a radiation counting unit 31 Ns counter 32 demultiplexer 33 counter 34 determination circuit unit 35 Nc Counter 36 Determination circuit unit 37 Nd counter 40 Calculation unit 40a Calculation unit 40b Calculation unit 41 Mobile phone terminal 42 Communication device 43 Display device 44 Radiation measurement device

Claims (17)

A radiation detector that detects radiation and outputs a pulse;
A radiation measurement apparatus comprising a radiation dose calculation unit that calculates a radiation dose by counting the pulses,
The radiation detector is
First and second radiation sensors that output electrical signals in response to the incidence of radiation;
A value corresponding to a signal obtained by subtracting the output signal of the first radiation sensor from the output signal of the second radiation sensor is within a range between a first value greater than 0 and a second value less than 0. If not, a radiation measurement apparatus comprising a pulse output circuit unit that outputs the pulse. The radiation measurement apparatus according to claim 1,
The pulse output circuit section is
A subtractor that outputs a voltage corresponding to a signal obtained by subtracting the output of the first radiation sensor from the output of the second radiation sensor;
A first comparator that outputs a high-level pulse signal when the output voltage of the subtractor is equal to or higher than the first value;
A second comparator that outputs a high-level pulse signal when the output voltage of the subtractor is less than or equal to the second value;
A radiation measuring apparatus comprising: an OR gate circuit that outputs a logical sum of an output of the first comparator and an output of the second comparator as the pulse. The radiation measurement apparatus according to claim 1,
The pulse output circuit section is
A first amplifier for amplifying the output of the first radiation sensor;
A second amplifier for amplifying the output of the second radiation sensor;
A subtractor that outputs a voltage obtained by subtracting the output voltage of the first amplifier from the output voltage of the second amplifier;
A first comparator that outputs a high-level pulse signal when the output voltage of the subtractor is not less than a value obtained by multiplying the first value by the gain of the second amplifier;
A second comparator that outputs a high-level pulse signal when an output voltage of the subtractor is equal to or less than a value obtained by multiplying the second value by the gain of the first amplifier;
A radiation measuring apparatus comprising: an OR gate circuit that outputs a logical sum of an output of the first comparator and an output of the second comparator as the pulse. The radiation measurement apparatus according to claim 1,
The pulse output circuit section is
A differential amplifier that amplifies and outputs a difference obtained by subtracting the output signal of the first radiation sensor from the output signal of the second radiation sensor;
A first comparator that outputs a high-level pulse signal when the output voltage of the differential amplifier is equal to or greater than the first value multiplied by the gain of the differential amplifier;
A second comparator that outputs a high-level pulse signal when the output voltage of the differential amplifier is less than or equal to a value obtained by multiplying the second value by the gain of the differential amplifier;
A radiation measuring apparatus comprising: an OR gate circuit that outputs a logical sum of an output of the first comparator and an output of the second comparator as the pulse. It is a radiation measuring device of any one of Claims 1-4, Comprising:
The radiation measuring apparatus, wherein the first value and the absolute value of the second value are equal. The radiation measuring apparatus according to any one of claims 1 to 5,
The radiation measurement apparatus, wherein the first radiation sensor and the second radiation sensor are arranged symmetrically in the radiation measurement apparatus. It is a radiation measuring device of any one of Claims 1-6,
The radiation dose calculator
A radiation counter that counts the pulses and outputs the total number of pulses counted within the measurement time;
A calculation unit for calculating the radiation dose based on the total number,
The radiation counting unit counts the pulses for each time slot having a certain time width, and when there are time slots in which a predetermined number or more of pulses are counted, the counting is performed in the time slot and the time slots before and after the time slot. The radiation measurement apparatus characterized in that the number of applied pulses is not included in the total number. The radiation measurement apparatus according to claim 7,
When the radiation detection unit detects the maximum amount of radiation that is assumed, there is a predetermined probability that there is a predetermined number or more of radiation pulses, which are pulses derived from the radiation, estimated from the Poisson distribution. The radiation measuring apparatus, wherein the time width is set so as to be as follows. The radiation measurement apparatus according to claim 8,
The calculation unit calculates the average occurrence rate λ per time slot, where μ is the average number of counted pulses per time slot calculated based on the total number.

A radiation measuring apparatus for correcting the radiation dose as described above. A radiation measurement apparatus according to any one of claims 7 to 9, wherein
When the calculation unit assumes that the pulse is only a radiation pulse that is a pulse caused by radiation, the number of pulses counted in the time slot includes the number of time slots that are not included in the total number. A second ratio to the total number of time slots within the measurement time;
Calculating a first ratio of the number of time slots in which the number of pulses counted in the time slot is not included in the total number to the total number of time slots within the measurement time;
A radiation measurement apparatus, wherein a calculated radiation dose is invalidated when a third ratio obtained by subtracting the second ratio from the first ratio is greater than a predetermined value. It is a radiation measuring device of any one of Claims 7-10, Comprising:
When the calculation unit assumes that the pulse is only a radiation pulse that is a pulse caused by radiation, the number of pulses counted in the time slot includes the number of time slots that are not included in the total number. A second ratio to the total number of time slots within the measurement time;
Calculating a first ratio of the number of time slots in which the number of pulses counted in the time slot is not included in the total number to the total number of time slots within the measurement time;
Based on the third rate Q obtained by subtracting the second ratio from the first rate, the average incidence per time slot 1 / (1-Q) times and to Rukoto radiation measurement apparatus, characterized in . It is a radiation measuring device of any one of Claims 7-11,
A radiation measurement apparatus comprising a plurality of the radiation detection units and the radiation counting units. It is a radiation measuring device of any one of Claims 1-12,
The radiation measurement apparatus, wherein the radiation sensor is a semiconductor sensor. The radiation measurement apparatus according to claim 13,
The radiation measurement apparatus, wherein the semiconductor sensor is a PIN photodiode. The radiation measurement apparatus according to claim 13,
The semiconductor sensor includes a scintillator and a photodiode.   The electronic device carrying the radiation measuring device of any one of Claims 1-15.   A mobile phone terminal equipped with the radiation measuring apparatus according to claim 1.

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