JP2013113678A - Radiation dose measurement system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radio communication type radiation dose measurement system by which dosage measurement is possible over a long period.SOLUTION: A radiation dose measurement system is constituted of: a plurality of wireless dose meters by which packet radio communication is possible; and relay radio communication equipment.The wireless dose meters include: packet data creation parts 10f4 which create packet data including dose data and identification data; random number generators 10g which generate random number data; transmission timing control parts 10f2 which control transmission timing of the packet data according to the generated random numbers; and transmission control parts 10f5 which perform transmission in the controlled transmission timing. The relay radio communication equipment includes: receiving means for receiving signals from the plurality of wireless dose meters; data extraction means for extracting digital dose data and identification data on the respective wireless dose meters from the packet data included in the received signals; and transmitting means for transmitting the digital dose data to be specified by the extracted identification data to a terminal.

Description

  The present invention relates to a radio communication type radiation dose measurement system.

  As a radiation measurement system using wireless communication, in Patent Document 1, a plurality of portable devices carried by each worker and communication areas are individually set and distributedly arranged to perform wireless communication with each portable device. In addition, a measurement system including a plurality of base stations and a host device connected to each base station and configured to transmit measurement data from each portable device to the host device via the base station is disclosed.

  According to such a measurement system, the portable device is mounted in, for example, an operator's pocket or the like, and the personal exposure dose is measured by the portable device. The measurement data is transmitted to the base station using the wireless communication function of the portable device, and further transmitted to the host device. Here, each base station is individually set in charge area, the host device identifies the area exposed to the worker by identifying the base station that received the dose data according to such area settings, It becomes possible to grasp the dose in the area.

Japanese Patent No. 3273915

  According to the radiation measurement system described in Patent Document 1, it is possible to grasp the radiation dose for each work area specified by the base station, but only the work area where the worker enters can be grasped. The radiation dose cannot be measured in an area where the worker is not allowed to enter or an area where the worker is not allowed to enter but is not prohibited.

  In order to measure radiation dose in areas where workers are not allowed to enter or areas where workers are not allowed to enter but are not allowed to enter, wireless measurement terminals must be fixedly installed in each area.

  As described above, when the wireless measurement terminal is fixedly installed, the problem is the battery life of each measurement terminal. Recently, long-life batteries have also been developed. However, when using a conventional wireless measurement terminal that consumes a lot of power, frequent battery replacement is required, and it can operate without battery replacement over a long period of time. It was extremely difficult to do.

  Accordingly, an object of the present invention is to provide a radio communication type radiation dose measuring system capable of performing dose measurement unattended for a long period even in an area where the radiation dose is high.

  The radiation dosimetry system of the present invention includes a plurality of wireless dosimeters, and a relay wireless communication apparatus capable of packet radio communication with the plurality of wireless dosimeters and connected to a network. Each wireless dosimeter includes a radiation sensor that outputs a detection signal according to the radiation dose, a signal processing unit that obtains digital dose data representing the radiation dose from the detection signal output from the radiation sensor, and the obtained digital dose data. And packet data generation means for generating packet data including identification data of the wireless dosimeter, random number generation means for generating random number data, timing control means for controlling the transmission timing of packet data according to the generated random number, and packet Transmission means for transmitting a high-frequency signal including data at this controlled transmission timing is provided. The relay radio communication apparatus includes a receiving unit that receives a plurality of high-frequency signals transmitted from a plurality of wireless dosimeters, and digital dose data and identification data of each wireless dosimeter from packet data included in the obtained plurality of received signals. And data transmitting means for transmitting digital dose data for each wireless dosimeter specified by the extracted identification data to at least one terminal.

  Radiation dose measurement values measured by a plurality of wireless dosimeters are transmitted to a relay radio communication device capable of packet radio communication with the plurality of wireless dosimeters, and then transmitted from the relay radio communication device to a terminal. The two-stage transmission system is used. Therefore, each wireless dosimeter does not need to perform long-distance wireless transmission, so it is only necessary to have a transmission function with short-distance power consumption, and power consumption as a wireless dosimeter can be reduced. . In addition, each wireless dosimeter controls the transmission timing of the packet data according to the random number generated by the random number generator, and transmits a high-frequency signal including the packet data at the controlled transmission timing. In this way, since it is possible to control the timing according to the generated random number and avoid collision without detecting and judging whether transmission is performed from another wireless dosimeter, the circuit configuration can be simplified. The power consumption can be reduced and the manufacturing cost can be reduced. Since the power consumption is small, frequent battery replacement is unnecessary, and it is possible to operate unattended without battery replacement over a long period of time.

  Each wireless dosimeter further includes an error detection code generation means for generating an error detection code to be added to the packet data, and the relay radio communication apparatus includes an error detection means for performing error detection on packet data included in a plurality of received signals. Furthermore, it is preferable to provide.

  The transmission means preferably includes network transmission means for transmitting digital dose data for each wireless dosimeter to an access point of the network.

  In this case, the network transmission means of the relay wireless communication apparatus is preferably wireless LAN means for transmitting digital dose data for each wireless dosimeter to the access point of the network by radio. Furthermore, it is more preferable that the wireless LAN unit is a low transfer rate WiFi transmission unit.

  The network transmission means of the relay wireless communication apparatus is preferably a wired LAN means for transmitting digital dose data for each wireless dosimeter to the network access point by wire.

  Each wireless dosimeter preferably further comprises a lithium battery that provides power to all elements within the wireless dosimeter.

  It is also preferable that the transmission means of each wireless dosimeter is configured to transmit a high-frequency signal of 950 MHz or 2.4 GHz at the transmission timing described above.

  According to the present invention, since a two-stage transmission system is used, the power consumption of each wireless dosimeter can be reduced. Further, the circuit configuration can be simplified, and accordingly, the power consumption can be reduced and the manufacturing cost can be reduced. Since the power consumption is small, frequent battery replacement is unnecessary, and it is possible to operate unattended without battery replacement over a long period of time.

1 is a block diagram schematically showing an overall configuration of a radiation dose measurement system as one embodiment of the present invention. FIG. It is a block diagram which shows roughly the structure of each wireless dosimeter in the radiation dosimetry system of FIG. 3 is a flowchart schematically showing a partial operation of the MCU in the wireless dosimeter of FIG. 2. 3 is a flowchart schematically showing a partial operation of the MCU in the wireless dosimeter of FIG. 2. 3 is a flowchart schematically showing a partial operation of the MCU in the wireless dosimeter of FIG. 2. FIG. 2 is a block diagram schematically showing a functional configuration of transmission timing control and packet generation realized by an MCU in the wireless dosimeter of the radiation dosimetry system of FIG. 1. It is a block diagram which shows schematically the other structure containing the relay radio | wireless communication apparatus in the radiation dose measurement system of FIG.

  FIG. 1 schematically shows the overall configuration of a radiation dose measurement system as an embodiment of the present invention.

In the figure, 10 ₁ to 10 _n are a plurality of wireless dosimeters distributed in the area to be measured, and 11 is a single wireless radiometer that is arranged to be able to perform packet radio communication with the plurality of wireless dosimeters 10 ₁ to 10 _n . relay radio communication devices 13 relay wireless communication device 11 is connected wirelessly or wired, network access point 14, for example a network such as the internetwork 14, 15 ₁ to 15 _m is connectable to the Internet 14 For example, terminals such as portable terminals and fixed terminals are shown.

  FIG. 2 schematically shows the configuration of each wireless dosimeter in the radiation dose measurement system of the present embodiment.

  In this figure, reference numeral 10a in the present embodiment is mainly composed of a PIN photodiode, for example, and indicates a sensor capable of detecting radiation such as gamma rays and X-rays. Although not shown, a light blocking film is attached to the detection window of the sensor 10a so as not to detect infrared light, ultraviolet light and visible light. The output of the sensor 10a includes an input of a high-pass filter / amplifier 10b including a high-pass filter for blocking electromagnetic waves having a long wavelength such as X-rays and an amplifier for amplifying the sensor output with an amplification factor of 100 to 200 times. It is connected. The output of the high-pass filter / amplifier 10b is connected to an input of a low-pass filter 10c for mainly blocking noise, and one input of a pulse detection comparator 10d is connected to the output of the low-pass filter 10c. . The output of the comparison voltage generator 10e is connected to the other input of the pulse detection comparator 10d.

  The pulse detection comparator 10d generates a rectangular wave pulse corresponding to the radiation detection pulse from the sensor 10a by comparing the output voltage of the low-pass filter 10c with the comparison reference voltage from the comparison voltage generator 10e. The output of the pulse detection comparator 10d is connected to the interrupt input of the micro control unit (MCU) 10f.

  The input of the MCU 10f is connected to the output of a random number generator 10g that generates a pseudo random number sequence for transmission timing control, and further generates a CRC (Cyclic Redundancy Check) code, which is an example of an error detection code. The output of the CRC generator 10h that supplies the generator polynomial is connected. The MCU 10f is mainly composed of a microcomputer including a computing unit, a memory including a RAM and a ROM, an input / output port, an input / output interface, a timer, and the like.

  The output of the MCU 10f is connected to an input of a transceiver 10i that modulates packet data from the MCU 10f into a high-frequency signal in a single frequency band (950 MHz or 2.4 GHz) and transmits it at a transmission timing controlled by the MCU 10f. The input of the transceiver 10i is further connected to the output of an identification code generator 10j that generates a 40-bit identification code for preventing interference. The output of the transceiver 10i is connected to the chip antenna 10l via the filter matching circuit 10k.

  The wireless dosimeter further includes a sensor 10a, a high-pass filter / amplifier 10b, a pulse detection comparator 10d, a comparison voltage generator 10e, an MCU 10f, a random number generator 10g, a CRC generator 10h, a transceiver 10i, and an identification code generator 10j. A power source 10m is provided by a lithium battery that supplies 3V power. Since the lithium battery is a power source, the life can be extended. Therefore, also from this point, frequent battery replacement is unnecessary, and it is possible to operate unattended without battery replacement for a long period of time.

  3 to 5 schematically show a partial operation flow of the MCU 10f in each wireless dosimeter according to the present embodiment. Hereinafter, the operation of the MCU 10f will be described with reference to these drawings.

  When a rectangular wave pulse corresponding to the radiation detection pulse is applied from the pulse detection comparator 10d, the MCU 10f executes a pulse interruption process shown in FIG.

  That is, the preset soft counter is incremented by 1 (step S1), and this interrupt process is terminated. The number of radiation detection pulses is counted by this interruption process. In addition, instead of the soft counter by the MCU 10f, a counter by hardware may be provided for counting. According to the hardware counter, power consumption can be reduced.

Meanwhile, MCU10f executes a first timer interrupt processing shown in FIG. 4 for each predetermined time based on an external timer 10f _3, such as, for example, a crystal oscillator.

  First, the counter value of the soft counter is read (step S11).

  Next, the number of radiation detection pulses within a predetermined time is calculated from the difference between the read counter value and the counter value at the previous interrupt processing (step S12).

Next, by multiplying the calculated number of radiation detection pulses within a predetermined time by a calibration value, which is a constant proportional to the sensitivity of the sensor, a radiation dose, an integrated value of the radiation dose, and the like are calculated. dose data, the integrated value data, by storing the detected time data or the like into the memory 10f ₁ (step S13), and terminates the first timer interrupt processing. By this first timer interruption process, radiation dose data, its integrated value data, detected date / time data, and the like are calculated.

MCU10f in every time corresponding to one time slot based on an external timer 10f ₃ has elapsed, performing a second timer interrupt processing shown in FIG.

  First, if the counter value that has been reset to “0” in advance is k, whether or not the content RS (k) of the kth bit of the pseudorandom number sequence RS obtained from the random number generator 10g is “1”. Is determined (step S21).

  When RS (k) = 1 (in the case of YES), transmission of packet data is permitted in the time slot corresponding to this interrupt process (step S22). When RS (k) = 1 is not satisfied (in the case of NO), transmission of packet data is not permitted in the time slot corresponding to the interrupt process, and the counter value k is incremented by 1 (step S23).

  Next, it is determined whether or not the counter value k has reached the last bit of the pseudo-random number sequence RS (step S24). If the counter value k has not reached the last bit (in the case of NO), the counter value k is not reset. When the second timer interrupt process is finished and the final bit is reached (in the case of YES), the counter value k is reset to “0” (step S25), and this second timer interrupt process is finished. A pseudo-random number sequence is generated by the second timer interrupt process.

  FIG. 6 schematically shows a functional configuration of transmission timing control and packet generation realized by the second timer interrupt processing (FIG. 5) of the MCU 10f in the wireless dosimeter of the radiation dosimetry system of this embodiment. Yes.

In the figure, the memory 10f ₁ is a memory in MCU10f, stores control programs and ID of the wireless dosimeter (device number).

  The random number generator 10g generates “1” and “0” pseudo-random number sequences, for example, M-sequence pseudo-random number sequences, according to a predetermined algorithm. This pseudo-random number sequence is generated based on an initial value set according to the ID of each wireless dosimeter so as to be a different random number sequence for each wireless dosimeter.

Transmission timing control section 10f _2, based on the pseudo-random number generated by the random number generator 10 g, to determine the timing of the signal sent from the transmission control unit 10f ₅ to the transceiver 10i. For example, during the time slot in which the corresponding bit of the pseudo random number sequence is “1”, the transmission control unit 10f ₅ is permitted to transmit a signal generated by the packet generation unit 10f _{4 and} the corresponding pseudo random number sequence corresponds. bits between time slots is "0" inhibits the signal transmission of the packet to the transmission control unit 10f _5. In other words, each time slot corresponds to each bit of the pseudorandom number sequence.

Packet generating unit 10f ₄ generates a packet data included in the signal transmitted by the transmission control section 10f ₅ (packet frame). The packet data includes a frame start flag, a header including the ID of the relay radio communication apparatus 11 as a destination and the ID of the wireless dosimeter itself as a transmission source, a payload including a data body to be transmitted, an error detection code, and a frame. The trailer including the end flag is included in this order.

  The generator polynomial generated by the CRC generator 10h is used to divide the data of the transmission bit string of the packet, and the remainder is added to the packet data as a CRC code which is an example of an error detection code.

The transmission control unit 10f _5, depending on the transmission timing determined by the transmission timing control section 10f _2, performs transmission control of a signal including a packet generated by the packet generation unit 10f _4. Specifically, execution and stop of a signal transmitted from the antenna 10l through the transceiver 10i are controlled. Since the transmission time of the packet data output from the transceiver 10i is as short as 150 to 250 μ · sec, the possibility of packet collision is small from this point of view. Even if there is a collision, since the next timing is controlled by a random number, there is a high possibility that the collision can be avoided. Incidentally, the collision probability for 10 seconds between the two transmitters is about 1/80000.

  Each wireless dosimeter is in sleep state when there is no data transfer, and the connection algorithm has been improved so that the rise from sleep state is faster. Is reduced.

  FIG. 7 schematically shows the relay wireless communication device 11 and other configurations in the radiation dose measurement system of this embodiment.

As shown in the figure, the relay wireless communication device 11 can access an access point 13 by WiFi, which is a kind of wireless LAN (local area network), via an antenna 12, and the access point 13 is accessible via the LAN. Connected to a network such as the Internet. Furthermore, terminals 15 ₁ to 15 ₃ such as mobile terminals and fixed terminals are connected to the network 14 so as to be accessible.

The relay wireless communication device 11 has an antenna 11a that receives antenna signals from a plurality of wireless dosimeters 10 ₁ to 10 _n (see FIG. 1), and an input connected to the antenna 11a via a filter matching circuit 11b. A transceiver 11c, an MCU 11d whose input is connected to the output of the transceiver 11c, a WiFi module 11e whose input is connected to the output of the MCU 11d, and a wireless LAN antenna 11f connected to the output of the WiFi module 11e I have.

  The transceiver 11c demodulates a high frequency signal in a single frequency band (950 MHz or 2.4 GHz) from a plurality of wireless dosimeters, extracts packet data, and outputs the packet data to the MCU 11d. According to the 950 MHz band, the communication distance is about 100 to 1000 m. According to 2.4 GHz, the communication distance is long and about 50 m, but the power consumption is low.

  The MCU 11d is mainly composed of a microcomputer including an arithmetic unit, a memory including a RAM and a ROM, an input / output port, an input / output interface, a timer, and the like. The packet data input from the transceiver 11c is generated in the same way as the transmission side. Error detection is performed by dividing by a polynomial and dividing. Then, the ID and radiation dose data of the wireless dosimeter of the transmission source are extracted, and the radiation dose data for each wireless dosimeter specified by the extracted ID, its integrated value data, and the detected date / time data are stored in the memory. At the same time, the address of the terminal to which these data are to be transmitted is attached, and the data is transmitted from the WiFi module 11e to the WiFi access point 13 via the antennas 11f and 12. Thereby, the terminal corresponding to the address can receive data including radiation dose data for each wireless dosimeter specified by the ID, integrated value data thereof, detected date / time data, and the like via the network 14. .

  The WiFi module 11e is configured to be capable of adjusting the output according to the communication distance, such as setting the communication rate slower than normal (1 Mbps) and reducing the output when the distance to the WiFi access point 13 is short. Low power consumption can be reduced. In addition, since the connection algorithm has been improved so that the sleep state is set when there is no data transfer and the rise from the sleep state is accelerated, the power consumption is also reduced in this respect.

The relay radio communication apparatus 11 is configured to receive a single frequency band signal from multiple wireless dosimeters 10 ₁ to 10 _n (up to 1024 in this embodiment) (see FIG. 1). In particular, in this embodiment, since the transmission time of each wireless dosimeter is as short as 150 to 250 μ · sec, a large number of signals in a single frequency band can be obtained without performing carrier sense for other wireless dosimeters. The probability of collision even after transmission is very low. In addition, since the transmission timing is controlled by random numbers, the possibility of subsequent collisions is lower.

As described above, according to this embodiment, the packet radio communication with a plurality of wireless dosimeter 10 ₁ to 10 _n a radiation dose measurements taken by a plurality of wireless dosimeter 10 ₁ to 10 _n Each wireless dosimeter performs a long-distance wireless transmission because it uses a two-stage transmission system in which the relay wireless communication device 11 transmits the data to the relay wireless communication device 11 and then transmits the relay wireless communication device 11 to the terminal. There is no need. For this reason, it is only necessary for the transceiver 10i to have a transmission function with low power consumption in a short distance, and the power consumption of the wireless dosimeter can be greatly reduced. In addition, each wireless dosimeter has a very short transmission time of 150 to 250 μ · sec, controls the transmission timing of packet data according to the random number generated by the random number generator 10g, and a high-frequency signal including the packet data Is transmitted at this controlled transmission timing so that data collision does not occur as much as possible. In this way, because it is configured to avoid collisions without detecting whether or not transmission is being performed from another wireless dosimeter, a circuit for the carrier sense becomes unnecessary, and the circuit The configuration can be simplified, the power consumption can be reduced, and the manufacturing cost can be reduced. In addition, each wireless dosimeter is put into a sleep state when there is no data transfer, and the connection algorithm has been improved to speed up the start from the sleep state. Is reduced. As described above, since the power consumption of the entire wireless dosimeter is small, and since the power source 10 m using the lithium battery is used, frequent battery replacement is unnecessary, and it is possible to operate unattended without battery replacement for a long period of time. be able to. This is very effective particularly when the radiation dose is constantly measured in an area where the radiation dose is high, or in an installation position or area where frequent radiation is not possible.

  In addition, the relay wireless communication device 11 is configured to be able to adjust the output according to the communication distance, for example, by setting the communication rate of the WiFi module 11e slower than normal and reducing the output when the distance to the WiFi access point 13 is short. Therefore, it is possible to reduce power consumption. In addition, since the WiFi module 11e is in the sleep state when there is no data transfer and the connection algorithm is improved so that the rise from the sleep state is accelerated, the power consumption is also reduced from this point. It becomes.

  In the above-described embodiment, the connection between the relay wireless communication apparatus and the network is performed by a wireless LAN using WiFi, but it is needless to say that both may be connected by a wired LAN.

  Further, when connecting via a WiFi wireless LAN, the relay wireless communication apparatus may be directly connected to a portable terminal or a fixed terminal having a WiFi function without being connected to the terminal via the network. .

  All the embodiments described above are illustrative of the present invention and are not intended to be limiting, and the present invention can be implemented in other various modifications and changes. Therefore, the scope of the present invention is defined only by the claims and their equivalents.

10 ₁ to 10 _n Wireless dosimeter 10a Sensor 10b High-pass filter / amplifier 10c Low-pass filter 10d Pulse detection comparator 10e Comparison voltage generator 10f, 11d MCU
10f ₁ memory 10f ₂ transmission timing control unit 10f ₃ external timer 10f ₄ packet generation unit 10f ₅ transmission control unit 10g random number generator 10h CRC generator 10i, 11c transceiver 10j identification code generator 10k, 11b filter matching circuit 10l chip antenna 10m power 11 relay wireless communication device 11a, 11f antenna 11e WiFi module 13 access points 14 network 15 ₁ to 15 _m terminal

Claims (8)

A plurality of wireless dosimeters, and a relay wireless communication device capable of packet radio communication with the plurality of wireless dosimeters and connected to a network;
Each of the wireless dosimeters includes a radiation sensor that outputs a detection signal according to a radiation dose, a signal processing unit that obtains digital dose data representing the radiation dose from the detection signal output from the radiation sensor, and the calculation Packet data generating means for generating packet data including digital dose data and identification data of the wireless dosimeter, random number generating means for generating random number data, and transmission timing of the packet data in accordance with the generated random number Timing control means, and a transmission means for transmitting a high-frequency signal including the packet data at the controlled transmission timing,
The relay radio communication device includes: a receiving unit that receives a plurality of high-frequency signals transmitted from the plurality of wireless dosimeters; a digital dose data of each wireless dosimeter from packet data included in the plurality of received signals obtained; Radiation dose measurement comprising data extraction means for extracting identification data, and transmission means for transmitting digital dose data for each wireless dosimeter specified by the extracted identification data to at least one terminal system.   Each of the wireless dosimeters further includes error detection code generation means for generating an error detection code to be added to the packet data, and the relay radio communication apparatus performs error detection on packet data included in the plurality of received signals. The radiation dose measurement system according to claim 1, further comprising an error detection unit.   3. The radiation dosimetry system according to claim 1, wherein the transmission means includes network transmission means for transmitting digital dose data for each wireless dosimeter to a network access point.   The radiation dose measurement according to claim 3, wherein the network transmission means of the relay wireless communication device is wireless LAN means for wirelessly transmitting digital dose data for each wireless dosimeter to an access point of the network. system.   5. The radiation dose measuring system according to claim 4, wherein the wireless LAN means is a low transfer rate WiFi transmitting means.   The radiation dose measurement according to claim 3, wherein the network transmission means of the relay wireless communication device is a wired LAN means for transmitting digital dose data for each wireless dosimeter to a network access point by wire. system.   The radiation dosimetry system according to any one of claims 1 to 6, wherein each of the wireless dosimeters further includes a lithium battery that supplies power to all elements in the wireless dosimeter. .   The transmission means of each wireless dosimeter is configured to transmit a high-frequency signal of 950 MHz or 2.4 GHz at the transmission timing. Radiation dosimetry system.

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