JP4525622B2 - Radiation detector - Google Patents

Description

  The present invention relates to a radiation detector, and is particularly suitable for application to a method for reducing current consumption of a radiation detector.

In nuclear power plants, accelerator facilities, and radiation utilization facilities, portable radiation detectors that fit in the pockets of radiation workers are used to detect and manage the radiation doses exposed to radiation workers. It has been.
FIG. 5 is a view showing a mounting state of the radiation detector, and FIG. 6 is a perspective view showing an external configuration of the conventional radiation detector.
5 and 6, the radiation detector 100 is set to a size that fits in the chest of the work clothes of a radiation worker, and has a size of approximately 100 × 50 × 10 mm. The radiation detector 100 is provided with a printed circuit board 115 on which a signal processing circuit is mounted, a casing 101 for housing the printed circuit board 115, a liquid crystal display 113 for displaying data, and an alarm unit 114 for alarming radiation workers. It has been. Here, as a radiation detection method, a semiconductor method using an ionization action by incident radiation has become the mainstream.

FIG. 7 is a block diagram showing a schematic configuration of a conventional radiation detector.
In FIG. 7, the radiation detector includes a semiconductor detection unit 2 that detects radiation, a reverse bias applying unit 1 that applies a reverse bias to the semiconductor detection unit 2, and an amplifier circuit that amplifies a signal detected by the semiconductor detection unit 2. 3. The signal output from the amplifier circuit 3 is compared with the threshold voltage, the comparator 4 that outputs a signal equal to or higher than the threshold voltage as a pulse signal, the counter 5 that counts the pulse signal output from the comparator 4, and the count result by the counter 5 A CPU 16 for calculating the radiation dose based on the above, a buzzer 8 for sounding an alarm when the radiation dose exceeds a prescribed value, a communication means 9 for communicating with the outside by IRDA or the like are provided. Here, the CPU 16 communicates based on the presence or absence of reception by the counter reading means 16a for reading the count result by the counter 5, the exposure dose calculating means 16b for calculating the radiation dose based on the count result by the counter 5, and the communication means 9. Communication processing means 16c for performing processing is provided.

  The radiation exposed by the radiation worker is incident on the semiconductor detection unit 2 through the housing 101, and the semiconductor detection unit 2 detects the radiation. The signal detected by the semiconductor detection unit 2 is amplified by the amplifier circuit 3 and then compared with the threshold voltage by the comparator 4, and a signal having a level equal to or higher than the threshold voltage is output to the counter 5 as a pulse signal. . The pulse signal from the comparator 4 is counted by the counter 5 and the count result is input to the CPU 16. Then, the CPU 16 can calculate the radiation dose to which the radiation worker is exposed based on the count result from the counter 5.

  And CPU16 will display on the liquid crystal display 113 the radiation exposure worker's present exposure radiation dose, if radiation dose is calculated. Moreover, CPU16 notifies that to the alarm part 114, when the radiation exposure worker's present exposure radiation dose exceeds the regulation value. When the alarm unit 114 receives a notification from the CPU 16 that the radiation exposure worker's current radiation exposure dose exceeds the specified value, the alarm unit 114 sounds the buzzer 8 to cause the radiation service worker to leave the work space. Can be urged.

FIG. 8 is a flowchart showing the operation of the conventional radiation detector.
In FIG. 8, when the power of the radiation detector is turned on (step S0), the CPU 16 performs the initial setting (step S1) and then reads the count result by the counter 5 (step S2). Then, the CPU 16 performs an exposure amount calculation process based on the count result by the counter 5, and performs a display process by the liquid crystal display 113 and an alarm process by the buzzer 8 based on the calculation result (step S3).

Next, the CPU 16 determines whether or not there is an IRDA communication signal transmitted from a host computer such as a personal computer (step S4). If there is no IRDA communication signal from the personal computer, the power switch is turned on / off. The state is confirmed (step S6). If the power switch is turned on, the CPU 16 enters a sleep state and stops the operation of the CPU 16 (step S8). On the other hand, when the power switch is turned off, the CPU 16 turns off the power of the radiation detector (step S7).
On the other hand, when the personal computer is near the radiation detector and receives the IRDA communication signal in step S4, the CPU 16 performs communication processing with the personal computer (step S5).

FIG. 9 is a timing chart showing the relationship between the active time and sleep time of the conventional CPU 16, and FIG. 10 is an enlarged timing chart showing the active time of the CPU 16 in FIG.
In FIG. 9, the CPU 16 operates for the active time Y (ms) in the cycle of the intermittent operation time X (ms), and stops the operation during the sleep time (XY) (ms), thereby reducing the power consumption. To achieve a longer battery life for the power supply.

Here, as shown in FIG. 10, the active time Y during which the CPU 16 operates includes (1) a data read time from the counter 5, (2) an exposure amount calculation time for calculating an exposure radiation dose, and (3) IRDA. It consists of a confirmation time for whether or not a communication signal is received.
Further, for example, Patent Document 1 discloses a low power consumption of an individual dose dosimeter by intermittently operating a single chip computer that reads a measurement value of a radiation measurement system counter based on an interval signal generated from a frequency divider. A method for achieving this is disclosed.
Japanese Patent Laid-Open No. 2-19788

However, in the conventional radiation detector, in order to confirm whether or not the IRDA communication signal is received, the intermittent operation time is set so that there is no waiting time when the radiation worker brings the radiation detector close to the personal computer. X is set short, and the intermittent operation time X needs to be about 1 second. For this reason, since the ratio of the active time Y to the sleep time (XY) of the CPU 16 increases and the current consumption of the CPU 16 increases, there is a problem that the life of the battery for the power supply of the radiation detector is shortened. .
SUMMARY OF THE INVENTION An object of the present invention is to provide a radiation detector capable of reducing power consumption while shortening a waiting time for confirming whether or not a communication signal is received.

In order to solve the above-described problem, according to the radiation detector according to claim 1, a pulse signal based on a radiation detection means for detecting radiation and a comparison result between a radiation detection signal and a threshold value by the radiation detection means. Is calculated by the calculation processing means, the counting means for counting the pulse signals output from the comparison means, the calculation processing means for calculating the radiation dose based on the counting result by the counting means, and the calculation processing means. A communication processing means for performing communication processing on information regarding the radiation dose received, and intermittently shifting only the communication processing means to an operating state at a predetermined timing in the intermittent operation time period, and a predetermined intermittent operation time period The arithmetic processing means and the communication processing means are intermittently operated at a timing other than the predetermined timing. Characterized in that it comprises an active control means for shifting.

  Thereby, it becomes possible to lengthen the intermittent operation time of the arithmetic processing means while making it possible to shorten the intermittent operation time of the communication processing means. For this reason, it is possible to frequently check whether or not a communication signal is received, while increasing the operation stop time of the arithmetic processing means, and waiting time required to check whether or not a communication signal is received. It is possible to reduce power consumption while shortening.

According to the radiation detector of claim 2, the number of times only the communication processing unit shifts to the operating state per unit time than the number of times the arithmetic processing unit and the communication processing unit shift to the operating state. It is characterized by more.
As a result, even when the operation stop time of the arithmetic processing means is extended, it is possible to frequently check whether or not a communication signal has been received, thereby reducing the waiting time for checking whether or not a communication signal has been received. However, low power consumption can be achieved.

  As described above, according to the present invention, it is possible to frequently check whether or not a communication signal is received, and to increase the operation stop time of the arithmetic processing means, thereby receiving the communication signal. It is possible to reduce the power consumption while shortening the waiting time for checking the presence / absence of this.

Hereinafter, a radiation detector according to an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram showing a schematic configuration of a radiation detector according to the first embodiment of the present invention.
In FIG. 1, the radiation detector includes a semiconductor detection unit 2 that detects radiation, a reverse bias applying unit 1 that applies a reverse bias to the semiconductor detection unit 2, and an amplifier circuit that amplifies a signal detected by the semiconductor detection unit 2. 3. The signal output from the amplifier circuit 3 is compared with the threshold voltage, the comparator 4 that outputs a signal equal to or higher than the threshold voltage as a pulse signal, the counter 5 that counts the pulse signal output from the comparator 4, and the count result by the counter 5 A CPU 6 for calculating the radiation dose based on the above, a buzzer 8 for sounding an alarm when the radiation dose exceeds a prescribed value, and a communication means 9 for communicating with the outside by means of IRDA or the like are provided.

  Then, the CPU 6 has a counter reading means 6 a for reading the count result by the counter 5, an exposure amount calculation means 6 b for calculating the radiation dose based on the count result by the counter 5, and a communication process based on the presence or absence of reception by the communication means 9. Is provided with communication processing means 6c for performing the above and active control means 6d for controlling the active state of the CPU 6. Here, the active control unit 6d intermittently shifts the counter reading unit 6a, the exposure amount calculation unit 6b, and the communication processing unit 6c to the operating state based on the first timing, and performs communication based on the second timing. Only the processing means 6c can be intermittently shifted to the operating state.

  When a reverse bias is applied to the semiconductor detection unit 2 by the reverse bias applying unit 1, electrons move from the n side to the p side, and the depletion layer of the diode structure included in the semiconductor detection unit 2 further expands. When radiation exposed to radiation workers enters the depletion layer of the semiconductor detector 2, electrons that are covalently bonded in the depletion layer are blown off, and a pair of electrons and holes (electron-hole pair) is generated. Generated.

  When a pair of electrons and holes is generated in the depletion layer, the electrons move in the + direction toward the reverse-biased electric field, and the holes move in the − direction. A current corresponding to the dose of incident radiation flows. Then, the signal detected by the semiconductor detection unit 2 is input to the amplifier circuit 3 after the direct current component is removed by a capacitor disposed in the preceding stage of the amplifier circuit 3. Then, the signal detected by the semiconductor detection unit 2 is amplified by the amplifier circuit 3, and then compared with the threshold voltage by the comparator 4, and a signal equal to or higher than the threshold voltage is output to the counter 5 as a pulse signal.

  The pulse signal from the comparator 4 is counted by the counter 5 and the count result is input to the CPU 6. Then, the CPU 6 reads the count result from the counter 5 by shifting to the active state at a predetermined cycle. Then, the CPU 6 calculates the exposure radiation dose of the radiation worker based on the count result from the counter 5. Further, the CPU 6 confirms whether or not an IRDA communication signal is received while shifting to the active state, and when receiving the IRDA communication signal, the CPU 6 performs communication processing with an external computer.

  Then, the CPU 6 can display the current exposure radiation dose of the radiation worker on the liquid crystal display 113 after calculating the exposure radiation dose. In addition, when the radiation exposure worker's current radiation exposure dose exceeds a prescribed value, the CPU 6 can prompt the radiation service worker to leave the work space by sounding the buzzer 8. Further, the CPU 6 can transmit the radiation dose to the exposure dose centralized management system via the wireless communication means 9. The exposure dose centralized management system can centrally manage the transition and cumulative value of the radiation dose of radiation workers.

  Here, when the CPU 6 shifts to the active state at the first timing, the CPU 6 checks whether the IRDA communication signal has been received while performing the reading process of the count result from the counter 5 and the calculation process of the radiation dose. In addition, when a transition is made to the active state at the second timing, only communication processing including confirmation of the presence / absence of reception of an IRDA communication signal is performed, reading processing of the count result from the counter 5 and exposure radiation The amount calculation process can be paused.

  Thereby, it becomes possible to lengthen the intermittent operation time of the counter reading means 6a and the exposure amount calculation means 6b while making it possible to shorten the intermittent operation time of the communication processing means 6c. For this reason, it is possible to frequently check whether or not the IRDA communication signal is received, while extending the operation stop time of the counter reading means 6a and the exposure amount calculating means 6b, and receiving the IRDA communication signal. It is possible to reduce the power consumption while shortening the waiting time for checking the presence / absence of this.

FIG. 2 is a flowchart showing the operation of the radiation detector according to the embodiment of the present invention.
In FIG. 2, when the power of the radiation detector is turned on (step S0), the CPU 6 makes an initial setting (step S1) and then determines whether or not it is a predetermined timing (step S9). In this case, the count result by the counter 5 is read (step S2). Then, the CPU 6 performs an exposure amount calculation process based on the count result of the counter 5, and performs a display process by the liquid crystal display 113 and an alarm process by the buzzer 8 based on the calculation result (step S3).

  Next, for example, the CPU 6 determines whether or not there is an IRDA communication signal transmitted from a host computer such as a personal computer (step S4). If there is no IRDA communication signal from the personal computer, the power switch is turned on / off. The state is confirmed (step S6). If the power switch is on, the CPU 6 enters a sleep state and stops the operation of the CPU 6 (step S8). On the other hand, when the power switch is turned off, the CPU 6 turns off the radiation detector (step S7).

On the other hand, when the personal computer is near the radiation detector and receives the IRDA communication signal in step S4, the CPU 6 performs communication processing with the personal computer (step S5).
On the other hand, in the case of a predetermined timing in step S9, the count result reading process (step S2) and the exposure amount calculation process (step S3) by the counter 5 are skipped, and whether or not an IRDA communication signal is received (step S4) ), And then the process proceeds to step S6.

FIG. 3 is a timing chart showing the relationship between the active time and the sleep time of the CPU 6 according to an embodiment of the present invention, and FIG. 4 is a timing chart showing an enlarged active time T2 of the CPU 6 at the timing B in FIG. is there.
In FIG. 3, in the period of the intermittent operation time X (ms), the CPU 6 performs (1) data read processing from the counter 5 and (2) exposure radiation dose calculation processing during the active time T1 (ms) at timing A. (3) A communication process including confirmation of whether or not an IRDA communication signal is received is performed, and the active time T2 (ms) at timing B includes (3) whether or not an IRDA communication signal is received, as shown in FIG. Only communication processing including confirmation is performed.

  Here, it is preferable that the number of transitions to the active time T2 is greater than the number of transitions to the active time T1 per unit time. As a result, even when the frequency of the data reading process from the counter 5 and the calculation process of the exposure radiation dose is reduced, 3) it is possible to frequently perform the communication process including the presence / absence of reception of the IRDA communication signal. It is possible to reduce power consumption while shortening the waiting time for confirming whether or not an IRDA communication signal is received.

  In addition, the radiation detector possessed by the radiation worker is not exposed to radiation unless the radiation worker is working in a high-level radioactive area. It becomes. For this reason, it is not necessary to frequently perform the data reading process from the counter 5 and the exposure radiation dose calculation process, and even when the frequency of the data reading process from the counter 5 and the exposure radiation dose calculation process is reduced, It can be avoided that the processing is disturbed.

It is a block diagram showing a schematic structure of a radiation detector concerning one embodiment of the present invention. It is a flowchart which shows operation | movement of the radiation detector which concerns on one Embodiment of this invention. It is a timing chart which shows the relationship between the active time of CPU16 and sleep time which concern on one Embodiment of this invention. 4 is a timing chart showing an enlarged active time of a CPU 16 at timing B in FIG. 3. It is a figure which shows the mounting state of a radiation dosimeter. It is a perspective view which shows the external appearance structure of the conventional radiation dosimeter. It is a block diagram which shows schematic structure of the conventional radiation detector. It is a flowchart which shows operation | movement of the conventional radiation detector. It is a timing chart which shows the relationship between the active time of conventional CPU16, and sleep time. It is a timing chart which expands and shows the active time of CPU16 of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Reverse bias application means 2 Semiconductor detection part 3 Amplifier circuit 4 Comparator 5 Counter 6 CPU
6a Counter reading means 6b Exposure amount calculating means 6c Communication processing means 6d Active control means 113 Liquid crystal display 8 Buzzer 9 Wireless communication means

Claims (2)

Radiation detection means for detecting radiation;
A comparison means for outputting a pulse signal based on a comparison result between a radiation detection signal and a threshold value by the radiation detection means;
Counting means for counting the pulse signals output from the comparison means;
Arithmetic processing means for calculating the radiation dose based on the counting result by the counting means;
Communication processing means for performing communication processing on information related to the radiation dose calculated by the arithmetic processing means;
Only the communication processing means is intermittently shifted to the operating state at a predetermined timing in the intermittent operation time period, and the arithmetic processing means and the communication processing are performed at a timing other than the predetermined timing in the predetermined intermittent operation time period. A radiation detector comprising: active control means for intermittently shifting the means to an operating state .   The number of times that only the communication processing unit shifts to the operating state is larger than the number of times that the arithmetic processing unit and the communication processing unit shift to the operating state per unit time. Radiation detector.

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