JP3556313B2 - Radiation measurement system - Google Patents

Description

[0001]
[Industrial applications]
The present invention relates to a radiation measurement system that measures radiation in accordance with an optical signal generated by a scintillator detector upon incidence of radiation.
[0002]
[Prior art]
Conventionally, in the field of radiation measurement, a radiation measurement system that measures radiation in accordance with a signal input from a radiation detector upon incidence of radiation has been widely used.
[0003]
FIG. 14 is a block diagram showing the configuration of this type of radiation measurement system. In this radiation measurement system, a plurality of radiation detectors 120 each including a detection element 121 such as NaI (Tl) and a measurement electronic circuit 122 are individually connected to a signal processing unit 125 via a metal cable 124.
[0004]
Here, in each radiation detector 123, radiation energy is converted into an electric signal by the detection element 121 and the measurement electronic circuit 122, and the form of an analog pulse train, a DC current value, or a pulse train after digital processing is converted via the metal cable 124. The detection signal is given to the signal processing unit 125 at.
[0005]
The signal processing unit 125 executes a radiation energy instruction, a warning output, and the like based on a detection signal received from each radiation detector 123.
[0006]
There is another type of radiation measurement system using a multiplex transmission unit. FIG. 15 is a block diagram showing the configuration of such a radiation measurement system. In this radiation measurement system, a detection signal output from each radiation detector 123 is provided to a multiplex transmission unit 131 via a metal cable 124, and the multiplex transmission unit 131 multiplexes each detection signal, as compared with the system shown in FIG. To the signal processing unit 132.
[0007]
By the way, in recent years, such a radiation measurement system using a scintillator detector having advantages of small size, high sensitivity, and separation from an electric circuit instead of the radiation detector has been disclosed in JP-A-3-242590 and It is disclosed in JP-A-6-59044. FIG. 16 is a block diagram showing a configuration of such a radiation measurement system. In this radiation measurement system, a plurality of scintillator detectors 11 are individually connected to a signal processing circuit 18 via a measurement optical fiber 12 and a photoelectric conversion circuit 13.
[0008]
Similarly, a radiation measurement system using the scintillator detector 11 has been announced at the Atomic Energy Society of Japan, "1994 Spring Annual Meeting" (March 29-31, 1994 at Tsukuba University) (program Number M47). In this radiation measuring system, each scintillator detector 11 sends an optical output from each end to an optical delay line 19 through each measuring optical fiber 12 in accordance with the radiation energy. Each optical delay line 19 delays an optical output individually and sends it to the photoelectric conversion circuit 13, and each photoelectric conversion circuit 13 photoelectrically converts the optical output into an electric signal and sends it individually to the delay circuit 16.
[0009]
Each of the delay circuits 16 delays the electric signal so as to be synchronized with the electric signal sent from the other delay circuit and sends it to the coincidence circuit 17.
[0010]
The coincidence circuit 17 transmits a count output signal to the signal processing circuit 18 when receiving the respective electric signals transmitted from the respective delay circuits 16 at the same time.
[0011]
The signal processing circuit 18 outputs a radiation energy instruction or a warning based on the count output signal.
[0012]
[Problems to be solved by the invention]
However, in the above radiation measurement system, when the scintillator detector 11 is used as shown in FIG. 16 instead of the radiation detector 123 of the system shown in FIG. Since the conversion circuit 13 is required, there is a problem that the price is greatly increased.
[0013]
Further, in the system shown in FIG. 14, since the detection signal output from the radiation detector 123 is processed by the measurement electronic circuit 122, traceability of the detection sensitivity by source calibration is ensured, and the radiation detector 123 The radiation measurement system can be calibrated by calibration of a single product.
[0014]
On the other hand, when the scintillator detector 11 is used, the characteristics of the radiation measurement system are determined by combining the characteristics of the scintillator detector 11 and the measurement optical fiber 12, so that the calibration of the scintillator detector 11 requires the use of the radiation measurement system. Calibration cannot be performed, and it is necessary to calibrate detection sensitivity for the entire radiation measurement system using a radiation source. Therefore, when a remarkable deviation is found in the calibration work, it is necessary to further examine and adjust whether the scintillator detector 11 or the measurement system after the measurement optical fiber 12 is abnormal. It takes time. In addition, during the calibration work, the measurement cannot be normally performed, and there is a problem that the continuity of the measurement is lost.
[0015]
The present invention has been made in consideration of the above circumstances, and can reduce the labor of calibration work while reducing the cost without requiring the number of photoelectric conversion circuits corresponding to the number of scintillator detectors. It is an object of the present invention to provide a radiation measurement system that can ensure continuity of the radiation.
[0016]
[Means for Solving the Problems]
The invention according to claim 1 has both ends, generates light corresponding to radiation energy, and outputs the light from the both ends. And connected in series with each other A plurality of scintillator detectors, and a plurality of measurement optical fibers for individually transmitting light output from each of the scintillator detectors , The optical fiber for each measurement A plurality of photoelectric conversion circuits for transmitting the electric signals, and the electric signals transmitted from each of the photoelectric conversion circuits, the same scintillator detector A plurality of delay circuits for individually transmitting the signals with a delay so as to cancel the delayed time, and a plurality of coincidence circuits for transmitting a count output signal when the electric signals transmitted from the respective delay circuits are simultaneously received. A signal processing circuit that outputs an instruction signal of the radiation energy based on a count output signal sent from each of the coincidence counting circuits, wherein each of the scintillator detectors can be individually connected; A plurality of calibration optical fibers for individually transmitting the light output from the scintillator detector, and the light transmitted by each of the calibration optical fibers is individually delayed to produce A plurality of calibration light delay line to be sent to the circuit The light output of each of the scintillator detectors is a high-output light source that generates high-output light having a different emission wavelength, and the light output is provided between any one of the scintillator detectors and the photoelectric conversion circuit; An optical coupler for guiding high-output light generated by the light source to the optical fiber for measurement, and a light-coupler provided in front of each of the photoelectric conversion circuits so as to shield each of the photoelectric conversion circuits from the high-output light from the high-output light source. A plurality of filters, provided between the scintillator detector and each filter, a plurality of branch lines for branching the light passing through the measurement optical fiber from the measurement optical fiber, A field auxiliary unit that detects high-output light of the high-output light source branched from the branch line and uses the detected high-output light as a power supply. It is a radiation measurement system provided with.
[0021]
[Action]
Therefore, the invention corresponding to claim 1 is: Connected in series with each other Multiple scintillator detectors , Light is generated corresponding to the radiation energy and output from both ends, and a plurality of measuring optical fibers individually transmit the light output from each scintillator detector. , Multiple photoelectric conversion circuits , Optical fiber for each measurement The optical signals individually transmitted are photoelectrically converted to generate electric signals, and the electric signals are transmitted. A plurality of delay circuits convert the electric signals transmitted from each of the photoelectric conversion circuits with respect to the same scintillator detector. Each of the simultaneous counting circuits sends out a count output signal when the electric signals sent from each of the delay circuits are received simultaneously, and the signal processing circuit sends the count output signal. Since it has a measurement system that outputs a radiation energy indication signal based on the count output signal sent from each coincidence circuit, Each scintillator detector connected in series Is each light Output Each of the delay circuits delays the output of the photoelectric conversion circuit and supplies the same to the coincidence circuit at the same timing while providing the same to the coincidence circuit at different timings, so that the number of photoelectric conversion circuits corresponding to the number of scintillator detectors is different. It is possible to reduce the price without the need.
[0022]
Furthermore, each scintillator detector can be individually connected, and a plurality of calibration optical fibers that individually transmit the light output from the connected scintillator detector, and the light transmitted by each calibration optical fiber are individually And a plurality of optical delay lines for calibration that are delayed and sent to the photoelectric conversion circuit, so that the labor for calibration can be reduced and continuity of measurement can be ensured.
[0026]
Claims 1 The invention corresponding to ,each The light output of the scintillator detector is different from the light output wavelength, and high-power light is generated.The optical coupler guides the high-power light generated by the high-power light source to the optical fiber for measurement. A high-power light source that shields each photoelectric conversion circuit from high-power light by a plurality of branch lines, branches the light passing through the measurement optical fiber from the measurement optical fiber, and branches the on-site auxiliary unit from each branch line High output light is detected and the detected high output light is used as a power source. , Present A power cable for the field auxiliary unit is not required, and the system can be simplified.
[0028]
【Example】
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0029]
FIG. 1 is a block diagram showing the configuration of the radiation measurement system according to the first embodiment of the present invention. In this radiation measurement system, both ends of the scintillator detector 11a are individually connected to photoelectric conversion circuits 13a and 13b via measurement optical fibers 12a1 and 12a2, an optical switch unit 15, and optical delay lines 19a1 and 19a2.
[0030]
Similarly, both ends of the scintillator detector 11b are individually connected to the photoelectric conversion circuits 13a and 13b via the measuring optical fibers 12b1 and 12b2, the optical switch unit 15, and the optical delay lines 19b1 and 19b2.
[0031]
On the other hand, two systems of calibration optical fibers 14 laid from a source calibration room (not shown) are individually connected to common photoelectric conversion circuits 13 a and 13 b via an optical switch unit 15 and an optical delay line 19.
[0032]
The photoelectric conversion circuits 13a and 13b are connected to a metal cable having a branch, and the metal cables are connected from the branch to the delay circuits 16, 16a1, 16a2, 16b1 and 16b2, respectively. Each of the delay circuits 16 is connected to a coincidence circuit 17, each of the delay circuits 16a1 and 16a2 is connected to a coincidence circuit 17a, and each of the delay circuits 16b1 and 16b2 is connected to a coincidence circuit 17b. Each of the coincidence circuits 17, 17a, 17b is connected to a common signal processing circuit 18.
[0033]
Here, each of the scintillator detectors 11a and 11b has a function of converting radiation energy into light and individually outputting the radiation energy from both ends to the measuring optical fibers 12a1, 12a2, 12b1, and 12b2.
[0034]
The measuring optical fibers 12a1, 12a2, 12b1, 12b2 individually guide the optical outputs of the scintillator detectors 11a, 11b to the optical switch unit 15.
[0035]
On the other hand, each calibration optical fiber individually guides the optical output given from the radiation source calibration room to the optical switch unit.
[0036]
The optical switch unit 15 has an optical switch corresponding to each of the measuring optical fibers 12a1, 12a2, 12b1, 12b2 and each of the calibrating optical fibers 14, and each of the measuring optical fibers 12a1, 12a2, 12b1, 12b2, and The optical output given from each calibration optical fiber 14 is given to each optical delay line 19, 19a1, 19a2, 19b1, 19b2 via each optical switch individually. Each optical switch can be individually opened and closed by an operator's setting operation or the like.
[0037]
Each of the optical delay lines 19, 19a1, 19a2, 19b1, and 19b2 individually delays each optical output provided from the optical switch unit 15 and sends it to the photoelectric conversion circuits 13a and 13b in order to share the photoelectric conversion circuit. And has a function of making the timings of the respective optical outputs supplied to the photoelectric conversion circuits 13a and 13b different from each other. Each of the optical delay lines 19, 19a1, 19a2, 19b1, and 19b2 is one of two optical outputs corresponding to one of the scintillator detectors 11a among the optical outputs provided from the scintillator detectors 11a and 11b through the optical switch unit 15. The outputs are delayed so as to have a time difference τa, and the outputs are delayed so as to have a time difference τb corresponding to the other scintillator detector 11b. Further, τa and τb are different values from each other.
[0038]
The photoelectric conversion circuits 13a and 13b have a function of photoelectrically converting the optical output transmitted from each of the optical delay lines 19, 19a1, 19a2, 19b1 and 19b2 into an electric signal, and transmitting the electric signal to a metal cable.
[0039]
The metal cable branches the electric signal sent from the photoelectric conversion circuits 13a and 13b at the branching unit and supplies the electric signal to the delay circuits 16, 16a1, 16a2, 16b1, and 16b2 in parallel.
[0040]
Each of the delay circuits 16, 16a1, 16a2, 16b1, and 16b2 can individually set a delay time, and has a function of individually delaying an electric signal given from each metal cable and giving the signal to the coincidence circuits 17, 17a, and 17b. Specifically, each electric signal corresponding to each light output of the same scintillator detector 11a (11b) is simultaneously supplied to the coincidence counting circuit 17a (17b) corresponding to the scintillator detector 11a (11b). Therefore, the delay time is set so as to cancel the time difference τa or the time difference τb.
[0041]
Each of the coincidence circuits 17, 17a, and 17b transmits a count output signal to the signal processing circuit 18 when the respective electric signals transmitted from the delay circuits 16, 16a1, 16a2, 16b1, and 16b2 are simultaneously received. is there.
[0042]
The signal processing circuit 18 has a function of outputting an instruction of radiation energy corresponding to each of the scintillator detectors 11a and 11b and the radiation source calibration room based on the count output signals sent from the coincidence circuits 17, 17a and 17b. It has a function that can output an alarm.
[0043]
Next, the operation of the radiation measurement system configured as described above will be described with reference to the omitted block diagram of FIG. 2 and the time chart of FIG.
[0044]
Now, the light output generated by the scintillator detector 11a is, as shown in FIG. 3A, from one and the other of both ends of the scintillator detector 11a via the measuring optical fibers 12a1 and 12a2, respectively. As shown in FIG. 3B, the output of one of the optical delay lines 19a1 is transmitted to the optical delay lines 19a1 and 19a2, and the output of the other optical delay line 19a2 is shown in FIG. The signals are individually delayed so as to have a time difference τa and sent to the photoelectric conversion circuits 13a and 13b.
[0045]
The photoelectric conversion circuits 13a and 13b generate electric signals by photoelectrically converting the optical outputs, respectively, and as shown in FIGS. 3D and 3E, these two electric signals are provided with a time difference τa from each other. Send out to metal cable.
[0046]
The two electric signals transmitted to the metal cable are respectively branched into two and transmitted to four delay circuits 16a1, 16a2, 16b1, and 16b2.
[0047]
Here, of the four delay circuits 16a1, 16a2, 16b1, 16b2, the two delay circuits 16a1, 16b1 connected to one photoelectric conversion circuit 13a are individually connected to one and the other coincidence counting circuits 17a, 17b. The two delay circuits 16a2 and 16b2 connected to the other photoelectric conversion circuit 13b are individually connected to one and the other coincidence counting circuits 17a and 17b.
[0048]
The delay times t1 and t2 of the two delay circuits 16a1 and 16a2 connected to one coincidence circuit 17a are individually set so as to have a time difference τa. However, t1 = τa + t2.
[0049]
As a result, of the outputs at both ends of the scintillator detector 11a, the one that arrives at the delay circuit earlier by the time difference τa is delayed by the delay circuit 16a1 at the delay time t1 (= τa) as shown in FIG. + T2) and applied to the coincidence circuit 17a. The output of the two ends of the scintillator detector 11a that arrives at the delay circuit later by the time difference τa is delayed by the delay time t2 in the delay circuit 16a2 as shown in FIG. It is provided to the circuit 17a.
[0050]
Therefore, the coincidence counting circuit 17a simultaneously receives electric signals from the two delay circuits 16a1 and 16a2 corresponding to the outputs of both ends of the scintillator detector 11a and counts the electric signals, as shown in FIG. Thus, the count output signal is sent to the signal processing circuit 18.
[0051]
The signal processing circuit 18 outputs an instruction of radiation energy based on the count output signal.
[0052]
Note that, of the four delay circuits 16a1, 16a2, 16b1, and 16b2 described above, the two delay circuits 16b1 and 16b2 connected to the other coincidence circuit 17b are individually set to have a time difference τb different from τa. Delay times t3 and t4 are set. However, t3 = τb + t4.
[0053]
As a result, of the outputs at both ends of the scintillator detector 11a, the one that arrives at the delay circuit earlier by the time difference τa is delayed by the delay time t3 (= τb + t4) by the delay circuit 16b1, and the coincidence counting circuit 17b And the one that arrives at the delay circuit later by the time difference τb is delayed by the delay time t4 by the delay circuit 16b2 and applied to the coincidence circuit 17b.
[0054]
However, the electric signals passing through the delay circuits 16b1 and 16b2 of τb are given to the coincidence circuit 17b at different timings because one of the total delay times is τb + t4 and the other is τa + t4. Therefore, as shown in FIG. 3 (k), it is not counted.
[0055]
That is, each of the coincidence circuits 17a and 17b counts each electric signal applied simultaneously to the predetermined scintillator detector 11a, while each electric signal applied at a different timing corresponding to the other scintillator detector 11b. Is not counted.
[0056]
As described above, even if the photoelectric conversion circuits 13a and 13b are made more common than before, the electrical signals can be discriminated and counted in accordance with the outputs of the scintillator detectors 11a and 11b.
[0057]
Further, in this embodiment, a calibration optical fiber 14 is laid from the radiation source calibration room for instrument calibration. Therefore, at the time of calibration, the scintillator detector 11a can be calibrated by removing the scintillator detector 11a from the measurement optical fibers 12a1 and 12a2 and connecting the scintillator detector 11a to the calibration optical fiber 14 in the source calibration room. Also, by attaching a reference light source to the measuring optical fibers 12a1 and 12a2 from which the scintillator detector 11a has been removed, the measuring optical fibers 12a1 and 12a2, the optical switch unit 15, the optical delay lines 19a1 and 19a2, the photoelectric conversion circuit 13a, It is possible to calibrate a measurement system composed of the delay circuit 16b, the delay circuits 16a1, 16a2, the coincidence circuit 17a, and the signal processing circuit 18. As the reference light source, for example, as shown in FIG. 4, a container 41 having optical connectors 42 at both ends, a transmitting member 43 provided between the optical connectors 42 and transmitting the emission wavelength of the scintillator, An optical pulse generator provided in the container 41 and stably generating a constant amount of light and a constant wavelength of light and providing the light to the transmitting member 43 can be used. As the light pulse generator 44, a light emitting diode or a scintillator including a temperature controller and a radiation source is used.
[0058]
Furthermore, at the time of the source calibration, the optical switch of the measurement system from which the scintillator detector 11a is removed is turned off, and the optical switch of the calibration optical fiber 14 which is normally off is turned on. Source calibration can be performed without affecting the measurement channel.
[0059]
As described above, according to the first embodiment, each of the optical delay lines 19a1, 19a2, 19b1, and 19b2 individually delays each optical output provided from the optical switch unit 15 to make the timing different from each other. 13a and 13b, the outputs of the photoelectric conversion circuits 13a and 13b are individually delayed so that the respective delay circuits 16a1 and 16a2 cancel the delay times due to the optical delay lines 19a1 and 19a2, and are simultaneously transmitted to the coincidence circuit 17a. Therefore, the photoelectric conversion circuits can be shared, and the cost can be reduced without requiring the number of photoelectric conversion circuits corresponding to the number of scintillator detectors.
[0060]
Further, according to the first embodiment, at the time of calibration, the scintillator detector 11a is detached from the measurement optical fibers 12a1 and 12a2 and connected to the calibration optical fiber 14 in the source calibration room, thereby detecting the scintillator. The measuring device 11a can be calibrated, and the reference light source 31 is attached to the measuring optical fiber 13 from which the scintillator detector 11a has been removed, so that the measuring optical fibers 12a1 and 12a2, the optical switch section 15, and the optical delay line 19a1 are provided. , 19a2, the photoelectric conversion circuits 13a, 13b, the delay circuits 16a1, 16a2, the coincidence counting circuit 17a, and the signal processing circuit 18 can be calibrated, so that even if an abnormal value is indicated, The identification is easy, and the labor of the calibration work can be reduced.
[0061]
Further, according to the first embodiment, the optical switch of the measurement system from which the scintillator detector 11a has been removed is turned off, and the optical switch of the calibration optical fiber that is normally off is turned on. Source calibration can be performed without affecting the measurement channel. Measurement continuity can be ensured.
[0062]
Next, a radiation measurement system according to a second embodiment of the present invention will be described.
[0063]
FIG. 5 is a block diagram showing the configuration of the radiation measurement system. The same parts as those in FIG. 1 are denoted by the same reference numerals, and detailed description thereof will be omitted. Only different parts will be described here.
[0064]
That is, the system of the present embodiment is a system in which the configuration of the system shown in FIG. 1 is simplified. Specifically, compared to the system shown in FIG. 1, the scintillator detectors 11a and 11b are connected in series with each other, and The configuration is such that the optical delay lines 19a1 to 19b2 of the measurement system are omitted. The optical delay lines 19a1 to 19b2 are unnecessary because the scintillator detectors 11a and 11b are connected in series, so that the timing of the optical output given to each of the photoelectric conversion circuits 13a and 13b naturally differs. Has been omitted.
[0065]
Thus, when the optical outputs generated by the scintillator detectors 11a and 11b are transmitted from both ends, the optical outputs are given to the photoelectric conversion circuits 13a and 13b with a time difference from each other as described above. At this time, the time difference between the light outputs sent from one end and the other end of one scintillator detector 11a is set to τa, and each light sent from the one end and the other end of the other scintillator detector 11b. Assuming that the time difference between the outputs is τb, the time differences τa and τb are individually canceled by the delay circuits 16a1 to 16b2, and the measurement is executed via the coincidence circuits 17a and 17b, as described above.
[0066]
Further, at the time of calibration, for example, by replacing one of the scintillator detectors 11a and 11b with one of the scintillator detectors 11a and the reference light source 31, the photoelectric converter corresponding to the one scintillator detector 11a can be replaced as described above. The measurement system including the conversion circuits 13a and 13b, the delay circuits 16a1 and 16a2, the coincidence counting circuits 17a, and the signal processing circuit 18 can be calibrated.
[0067]
Further, by removing the reference light source 31 and attaching one scintillator detector 11a and removing the other scintillator detector 11b and attaching the reference light source 31, the photoelectric conversion circuits 13a and 13b corresponding to the other scintillator detector 11b are provided. The measurement system including the delay circuits 16b1 and 16b2, the coincidence counting circuits 17b, and the signal processing circuit 18 can be calibrated.
[0068]
In the radiation source calibration room, the scintillator detector 11a (11b) is attached to the calibration optical fiber 14 as described above, so that the scintillator detector 11a (11b) is calibrated.
[0069]
As described above, according to the second embodiment, the optical delay lines 19a1 to 19b2 are reduced by connecting the scintillator detectors 11a and 11b in series as compared with the first embodiment, and the measuring optical fiber is used. It is possible to reduce the usage of 12a1 to 12b2.
[0070]
Next, a radiation measurement system according to a third embodiment of the present invention will be described.
[0071]
FIG. 6 is a block diagram showing the configuration of this radiation measurement system. The same parts as those in FIG. 1 are denoted by the same reference numerals, and detailed description thereof will be omitted. Only different parts will be described here.
[0072]
In other words, the system of the present embodiment enables the output of the system shown in FIG. 1 to be transmitted to a higher-level signal processing circuit 52 provided in a central control room or the like. A signal processing unit 53 as an I / F connected to the subsequent stage of the signal processing circuit 18, a multiplex transmission circuit 51 for transmitting an output of the signal processing unit 53 by time division multiplexing, and a multiplex transmission circuit 51. And a higher-level signal processing circuit 52 for processing the output. The multiplex transmission circuit 51 and the signal processing circuit 52 are connected to each other by an optical fiber or a coaxial cable.
[0073]
Here, as described above, it is assumed that measurement or calibration is executed, and the signal processing circuit 18 outputs an instruction of radiation energy.
[0074]
The signal processing unit 53 converts and outputs the output of the signal processing circuit 18 to the multiplex transmission circuit 51 according to the input specification of the multiplex transmission circuit 51. The multiplex transmission circuit 51 performs time division processing on the output of the signal processing unit 53 and outputs the processed signal to the upper signal processing circuit 52. The upper signal processing circuit 52 receives the time-divided and transmitted output, and executes a predetermined process.
[0075]
As described above, according to the third embodiment, as compared with the first embodiment, the output of the signal processing circuit 18 is transmitted via the signal processing unit 53 and the multiplex transmission circuit 51 to a higher-level signal provided in a central operation room or the like. It can be transmitted to the processing circuit 52.
[0076]
Further, according to the third embodiment, when the multiplex transmission circuit 51 is an existing one, simplification of the system due to easy connection and reduction of the cable usage by multiplex transmission can be realized.
[0077]
Next, a radiation measurement system according to a fourth embodiment of the present invention will be described.
[0078]
FIG. 7 is a block diagram showing the configuration of this radiation measurement system. The same parts as those in FIG. 5 are denoted by the same reference numerals, and detailed description thereof will be omitted. Only different parts will be described here.
[0079]
That is, the system of the present embodiment enables the output of the system shown in FIG. 5 to be transmitted to a higher-level signal processing circuit 52 provided in a central operation room or the like. , A signal processing unit 53 connected downstream of the signal processing circuit 18, a multiplex transmission circuit 51 for transmitting the output of the signal processing unit 53 by time division multiplexing, and processing the output of the multiplex transmission circuit 51. And an upper signal processing circuit 52. The multiplex transmission circuit 51 and the signal processing circuit 18 are connected to each other by an optical fiber or a coaxial cable.
[0080]
Here, as described above, it is assumed that measurement or calibration is executed, and the signal processing circuit 18 outputs an instruction of radiation energy.
[0081]
The signal processing unit 53 converts and outputs the output of the signal processing circuit 18 to the multiplex transmission circuit 51 according to the input specification of the multiplex transmission circuit 51. The multiplex transmission circuit 51 performs time division processing on the output of the signal processing unit 53 and outputs the processed signal to the upper signal processing circuit 52. The upper signal processing circuit 52 receives the time-divided and transmitted output, and executes a predetermined process.
[0082]
As described above, according to the fourth embodiment, as compared with the second embodiment, the output of the signal processing circuit 18 is transmitted via the signal processing unit 53 and the multiplex transmission circuit 51 to a higher-level signal provided in a central operation room or the like. It can be transmitted to the processing circuit 52.
[0083]
Further, according to the fourth embodiment, when the multiplex transmission device having the multiplex transmission circuit 51 is an existing one, the system can be easily connected to the existing one, thereby simplifying the system and using the cable by the multiplex transmission. Can be reduced.
[0084]
Next, a radiation measurement system according to a fifth embodiment of the present invention will be described.
[0085]
FIG. 8 is a block diagram showing a configuration of the radiation measurement system, and FIG. 9 is a schematic diagram showing a partial configuration of the radiation measurement system. The same parts as those in FIG. Are omitted, and only different parts will be described here.
[0086]
That is, the system of this embodiment is different from the system shown in FIG. 5 in that an on-site auxiliary unit that does not require a power cable is provided. Specifically, the scintillator detectors 11a and 11b are different from the system shown in FIG. The light output is provided between the optical switch unit 15 and the photoelectric conversion circuit 13a, and the high output light generated by the high output light source 72 is provided between the optical switch unit 15 and the photoelectric conversion circuit 13a. An optical coupler 71 for guiding the optical fiber 12a1 for measurement, and a photoelectric conversion circuit which is provided between the optical coupler 71 and the photoelectric conversion circuit 13a and in front of the photoelectric conversion circuit 13b, and which is provided from the high output light by the high output light source 71. A filter 76 for shielding 13a and 13b is provided between the scintillator detector 11a and the optical switch unit 15 and between the scintillator detector 11b and the optical switch unit 15, respectively. The branch line 73 for branching the light passing through the measuring optical fibers 12a1 and 12a2 from the measuring optical fibers 12a1 and 12a2, and the light output and the high level of the scintillator detectors 11a and 11b branched from the branch line 73. An on-site auxiliary unit 74 is provided which detects the high output light of the output light source 72 with the photodetector 75 and uses it as a power source.
[0087]
Here, the high output light source 72 generates, for example, high output light in an infrared region.
[0088]
The filter 76 has a wavelength of the light output of the scintillator detectors 11a and 11b as a transmission wavelength and blocks light of other wavelengths. Specifically, as shown in FIG. It transmits several hundred nm, which is the wavelength of scintillation light as an optical output, and blocks high-output light having other wavelengths.
[0089]
Thus, the high-output light generated by the high-output light source 72 travels through the optical coupling unit 71 toward the scintillator detectors 11a and 11b and the photoelectric conversion circuit 13a in the measurement optical fiber.
[0090]
At this time, the high-output light traveling toward the photoelectric conversion circuit 13a is blocked by the filter 76. On the other hand, the high-output light traveling toward the scintillator detectors 11a and 11b is branched at the branch line 73 and a part of the light travels to the on-site auxiliary unit 74.
[0091]
In the on-site auxiliary unit 74, the high output light is detected by the photodetector 75, and the detected high output light is converted into a power supply for operation using, for example, a photovoltaic effect.
[0092]
Thus, the on-site auxiliary unit 74 can execute a predetermined operation without providing a power cable.
[0093]
As described above, according to the fifth embodiment, the high-power light generated by the high-power light source 72 is guided to the on-site auxiliary unit 74 through the measuring optical fibers 12a1 and 12a2, and the on-site auxiliary unit 74 transmits the high-output light. Is converted to a power supply, so that a power cable for the on-site auxiliary unit is not required, and the system can be simplified.
[0094]
Next, a radiation measurement system according to a sixth embodiment of the present invention will be described.
[0095]
FIG. 11 is a block diagram showing the configuration of this radiation measuring system. The same parts as those in FIG. 5 are denoted by the same reference numerals, and detailed description thereof will be omitted. Only different parts will be described here.
[0096]
That is, the system of the present embodiment is a system obtained by making the system shown in FIG. 5 redundant. Specifically, in addition to the system shown in FIG. 5, the scintillator detectors 11m1 and 11m2 are connected in series with each other, and the measuring light A failure level monitoring circuit 93 that forms a standby measurement loop connected from the fiber 91 to the photoelectric conversion circuits 13a and 13b via the optical switch unit 15 and monitors the output of the signal processing circuit 18, and a failure level monitoring circuit An optical switch control circuit 92 which is controlled by 93 and individually controls on / off of each optical switch of the optical switch unit 15 is added. Note that the scintillator detectors 11a and 11b, which are also included in the system shown in FIG. 5, are connected in series with each other, and are connected to the photoelectric conversion circuits 13a and 13b via the optical switches 15 from the measuring optical fibers 12a1 and 12a2. Is defined as a regular system measurement loop.
[0097]
Here, as described above, it is assumed that measurement or calibration is executed, and the signal processing circuit 18 outputs an instruction of radiation energy.
[0098]
The failure level monitoring circuit 93 monitors the output of the signal processing circuit 18 and determines whether or not the instruction of the radiation energy has deviated from a predetermined range between the upper limit value and the lower limit value, as shown in FIG. When the determination result indicates a deviation from the predetermined range, an optical switch switching command is sent to the optical switch control circuit 92 indicating that the ON state of the service system is turned OFF and the OFF state of the standby system is turned ON.
[0099]
Upon receiving this optical switch switching command, the optical switch control circuit 92 switches the working optical switch from the on state to the off state and switches the standby optical switch from the off state to the on state. In addition, the switching time of the optical switch is generally within 100 ms in the case of the mechanical type.
[0100]
As described above, when an abnormal value is detected due to a failure or the like in the service system measurement loop, it is possible to switch to the standby system measurement loop, and it is possible to continuously perform measurement.
[0101]
As described above, according to the sixth embodiment, as compared with the second embodiment, a standby measurement loop is added, and the failure level monitoring circuit 93 monitors the output of the signal processing circuit 18 to detect an abnormal state. The measurement system is switched from the service system to the standby system via the optical switch control circuit 92 and the optical switch unit. Therefore, even when an abnormal value is detected due to a failure or the like in the service system measurement loop, the missing state is detected. And the measurement can be performed continuously.
[0102]
Next, a radiation measurement system according to a seventh embodiment of the present invention will be described.
[0103]
FIG. 13 is a block diagram showing the configuration of this radiation measurement system. The same parts as those in FIG. 5 are denoted by the same reference numerals, and detailed description thereof will be omitted. Only different parts will be described here.
[0104]
That is, the system of the present embodiment is a modification of the system shown in FIG. 11. Specifically, as compared with the system shown in FIG. 11, the failure level monitoring circuit 93 is omitted, and the outputs of the photoelectric conversion circuits 13a and 13b are reduced. A measurement circuit 94 for sending an optical switch switching command to the optical switch control circuit 92 when the value is higher than the determination value is provided.
[0105]
Here, as described above, when the measurement or calibration is performed, it is assumed that the photoelectric conversion circuits 13a and 13b output the electric signals to the delay circuits 16a1 to 16b2.
[0106]
The measurement circuit 94 monitors the outputs of the photoelectric conversion circuits 13a and 13b and determines whether or not the electric signal is higher than the determination value, as shown in FIG. When it is also high, an optical switch switching command is sent to the optical switch control circuit 92 indicating that the on state of the service system is turned off and the off state of the standby system is turned on.
[0107]
Upon receiving this optical switch switching command, the optical switch control circuit 92 switches the service optical switch from the ON state to the OFF state and switches the standby optical switch from the OFF state to the ON state.
[0108]
As described above, when an abnormal value due to a failure or the like is detected in the service system measurement loop, the system can be switched to the standby system loop, and measurement can be continuously performed.
[0109]
As described above, according to the seventh embodiment, as compared with the second embodiment, a standby measurement loop is added, and when the measurement circuit 94 monitors the outputs of the photoelectric conversion circuits 13a and 13b and detects an abnormality, Since the measurement system is switched from the service system to the standby system via the optical switch control circuit 92 and the optical switch unit 15, even if an abnormal value is detected due to a failure or the like in the service system measurement loop, the measurement is not performed. The state can be prevented, and the measurement can be performed continuously.
[0110]
Further, according to the present embodiment, especially when external light enters due to breakage of the measurement loop or the like, the measurement loop is switched so that the external light does not enter the photoelectric conversion circuits 13a and 13b and the photoelectric conversion circuit is protected. be able to.
[0111]
In addition, the present invention can be variously modified and implemented without departing from the gist thereof.
[0112]
【The invention's effect】
According to the first aspect of the present invention as described above, Connected in series with each other Multiple scintillator detectors , Light is generated corresponding to the radiation energy and output from both ends, and a plurality of measuring optical fibers individually transmit the light output from each scintillator detector. , Multiple photoelectric conversion circuits , Optical fiber for each measurement The optical signals individually transmitted are photoelectrically converted to generate electric signals, and the electric signals are transmitted. A plurality of delay circuits convert the electric signals transmitted from each of the photoelectric conversion circuits with respect to the same scintillator detector. Each of the simultaneous counting circuits sends out a count output signal when the electric signals sent from each of the delay circuits are received simultaneously, and the signal processing circuit sends the count output signal. Since it has a measurement system that outputs a radiation energy indication signal based on the count output signal sent from each coincidence circuit, Each scintillator detector connected in series Is each light Output Each of the delay circuits delays the output of the photoelectric conversion circuit and supplies the same to the coincidence circuit at the same timing while providing the same to the coincidence circuit at different timings, so that the number of photoelectric conversion circuits corresponding to the number of scintillator detectors is different. It is possible to provide a radiation measurement system which can reduce the price without requiring the radiation measurement.
[0113]
Furthermore, each scintillator detector can be individually connected, and a plurality of calibration optical fibers that individually transmit the light output from the connected scintillator detector, and the light transmitted by each calibration optical fiber are individually And a plurality of optical delay lines for calibration, which are delayed and sent to the photoelectric conversion circuit, can reduce labor for calibration work and ensure continuity of measurement.
[0117]
Claims 1 According to the invention of ,each The light output of the scintillator detector is different from the light output wavelength, and high-power light is generated.The optical coupler guides the high-power light generated by the high-power light source to the optical fiber for measurement. A high-power light source that shields each photoelectric conversion circuit from high-power light by a plurality of branch lines, branches the light passing through the measurement optical fiber from the measurement optical fiber, and branches the on-site auxiliary unit from each branch line High output light is detected and the detected high output light is used as a power source. , Present A power supply cable for the field auxiliary unit is not required, and a radiation measurement system that can simplify the system can be provided.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of a radiation measurement system according to a first embodiment of the present invention;
FIG. 2 is a block diagram for explaining an operation in the embodiment;
FIG. 3 is a time chart for explaining an operation in the embodiment;
FIG. 4 is a sectional view showing calibration of a reference light source in the embodiment.
FIG. 5 is a block diagram showing a configuration of a radiation measurement system according to a second embodiment of the present invention;
FIG. 6 is a block diagram showing a configuration of a radiation measurement system according to a third embodiment of the present invention;
FIG. 7 is a block diagram showing a configuration of a radiation measurement system according to a fourth embodiment of the present invention;
FIG. 8 is a block diagram showing a configuration of a radiation measurement system according to a fifth embodiment of the present invention;
FIG. 9 is a schematic diagram showing a partial configuration of the radiation measurement system according to the embodiment;
FIG. 10 is a filter characteristic diagram for explaining the operation in the embodiment;
FIG. 11 is a block diagram showing a configuration of a radiation measurement system according to a sixth embodiment of the present invention;
FIG. 12 is a block diagram for explaining the operation in the embodiment;
FIG. 13 is a block diagram showing a configuration of a radiation measurement system according to a seventh embodiment of the present invention;
FIG. 14 is a block diagram showing a configuration of a conventional radiation measurement system;
FIG. 15 is a block diagram showing a configuration of a conventional radiation measurement system;
FIG. 16 is a block diagram showing a configuration of a conventional radiation measurement system;
FIG. 17 is a block diagram showing a configuration of a conventional radiation measurement system.
[Explanation of symbols]
11a, 11b: scintillator detector, 12a1, 12a2, 12b1, 12b2: measurement optical fiber, 13a, 13b: photoelectric conversion circuit, 14: calibration optical fiber, 15: optical switch unit, 16, 16a1, 16a2, 16b1, 16b2: delay circuit, 17, 17a, 17b: coincidence circuit, 18: signal processing circuit.

Claims (1)

A plurality of scintillator detectors having both ends, generating light corresponding to the radiation energy, outputting this light from the both ends , and connected in series with each other ;
A plurality of measurement optical fibers for individually transmitting light output from each of the scintillator detectors ,
A plurality of photoelectric conversion circuits that individually generate a photoelectric signal by photoelectrically converting the light transmitted through each of the measurement optical fibers and transmit the electric signal,
A plurality of delay circuits that individually send out the electrical signals sent from each of the photoelectric conversion circuits so as to cancel the delayed time with respect to the same scintillator detector,
A plurality of coincidence circuits for transmitting a count output signal when simultaneously receiving the electric signals transmitted from each of the delay circuits;
A signal processing circuit that outputs an instruction signal of the radiation energy based on the count output signal sent from each of the coincidence circuits;
Each of the scintillator detectors can be individually connected, and a plurality of calibration optical fibers that individually transmit light output from the connected scintillator detectors,
A plurality of calibration optical delay lines that individually delay the light transmitted by each of the calibration optical fibers and send the light to the photoelectric conversion circuit ,
A light output of each of the scintillator detectors and a high output light source that generates high output light having a different emission wavelength,
An optical coupler that is provided between any one of the scintillator detectors and the photoelectric conversion circuit and guides high-output light generated by the high-output light source to the measurement optical fiber,
A plurality of filters provided in front of each photoelectric conversion circuit so as to shield each photoelectric conversion circuit from high output light by the high output light source,
A plurality of branch lines provided between each of the scintillator detectors and each of the filters, for branching light passing through the measurement optical fiber from the measurement optical fiber,
A radiation measurement system , comprising: an on-site auxiliary unit that detects high-output light of the high-output light source branched from each of the branch lines and uses the detected high-output light as a power supply .

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