JP2007047132A - Radiation irradiation determining method and radiation irradiation determining system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radiation irradiation determining method and a radiation irradiation determining system, which reduce work load on experimenter, and can objectively and precisely determine the presence or absence of radiation irradiation onto a sample, such as a food, a natural medicine or the like. <P>SOLUTION: In the radiation irradiation determining system 100, the food 101 is irradiated with an excitation light from an LED 102c controlled by a pulse-generating device 104; and the light emitted from the food 101 being irradiated with the excitation light is detected by a photomultiplier tube 102e via a filter 102d; the intensity of the emitted light that is detected is measured by a pulse counter 110 with time via a photon-counting unit 108, and the variation in the light intensity is calculated, based on the light intensity measured with time; and the presence or absence of the radiation irradiation onto the food 101 is determined, based on the calculated variation, by using an radiation irradiation determining device 112. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a radiation irradiation determination method and a radiation irradiation determination system for determining the presence or absence of radiation irradiation on a sample (food, crude drug, etc.).

  In Japan, irradiation of food is prohibited in principle under the Food Sanitation Law, except for the purpose of controlling the germination of potatoes. In addition, importing foods that have been irradiated overseas is prohibited. On the other hand, radiation irradiation to foods is actually performed mainly on foods such as spices and dried herbs. The purpose of this radiation irradiation is to extend the distribution period by utilizing the effects of radiation irradiation such as sterilization, insecticidal and germination control of food.

  Under such circumstances, establishment of a technique for determining the presence or absence of irradiation of food or herbal medicine is indispensable in order to properly manage food distribution and to guarantee a display indicating irradiated food.

  At present, methods for determining the presence or absence of irradiation of food (especially effective for spices) include, for example, the electron spin resonance (ESR) method recognized as an official method of CEN (European Standard Analysis Committee) And thermoluminescence (TL) method and photostimulated luminescence (PSL) method.

  The ESR method is a method in which a food is placed in a magnetic field, radicals in the food are measured, and the presence or absence of radiation irradiation on the food is determined based on the measurement result.

  The TL method is a method of determining the presence or absence of radiation irradiation from the amount of luminescence and a luminescence pattern (curve) by measuring the thermoluminescence of minerals collected from food. Specifically, in the TL method, first, a small amount of a luminous element (mineral substance) contained in food is separated and purified, and thermoluminescence of the luminous element is measured with an apparatus using a photomultiplier tube. Next, radiation (γ-rays) is irradiated to the light emitting element once measured for thermoluminescence, and thermoluminescence is measured again with an apparatus using a photomultiplier tube. Then, the ratio of the two measured thermoluminescence is compared with a predetermined threshold value to determine the presence or absence of radiation irradiation.

  The PSL method utilizes the fact that there is a relationship between the light (luminescence) in the visible light region generated from food by the excitation by infrared light irradiation and the history of radiation irradiation to the food. This is a method of discrimination (see Patent Document 1 and Non-Patent Document 1). Specifically, in the PSL method, first, light emitted from a food by irradiating the food with infrared light is measured by an apparatus using a photomultiplier tube. Then, the integrated value of the measured light intensity of light emission is compared with a threshold value (external standard value) obtained empirically in advance according to the type of food to be measured to determine the presence or absence of radiation irradiation. In other words, in the PSL method, using a measuring device that combines an infrared light irradiation device and a photomultiplier tube, first, the amount of luminescence is measured several times within a certain time interval at a time interval of 1 second or more. The integrated value of the emitted light amount is calculated. Next, the calculated integrated value is compared with a determination reference value (external standard value) obtained empirically in advance according to the type of food to be measured. Next, as a result of comparing the integrated value with the determination reference value, if the integrated value is larger than the determination reference value, it is determined as “irradiation”, and if the integrated value is smaller than the determination reference value, it is determined as “non-irradiation”. In the PSL method, since the food itself can be used, pretreatment like the TL method is not necessary.

European Patent Application No. 06929999 Sanderson D.C. C. W. et al, “Establishing Luminescence methods to detect irradiated food.”, Sci. Food Technology Today, 12 (2), pp. 97-102, 1998

  However, in the PSL method, since the integrated value of the measured light emission quantity is compared with a certain external reference value, the presence or absence of radiation irradiation to the food is determined. It was.

  The amount of light measured by the PSL method is affected not only by the radiation dose but also by the content of the luminescent element (mineral) in the food. In other words, the amount of light to be measured varies depending on the composition of the luminous element in the food. For this reason, when a food with a low content of the luminous element and irradiated with radiation is targeted, the food may be determined as “non-irradiated”. In addition, when a food with a high measured luminescence background value that is not irradiated with radiation is targeted, the food may be identified as “irradiated”.

  That is, in the PSL method, in determining whether or not food is irradiated with radiation, the integrated value of the measured light emission amount is compared with a certain external reference value, so there is a possibility that it cannot always be accurately determined. There was a problem that the discrimination result lacked objectivity.

  In addition, in the PSL method, in order to maintain the accuracy of discrimination, it is necessary to perform a large amount of light quantity measurement on the same type of food and to determine an external reference value in advance. There was a problem that it was a burden.

  The present invention has been made in view of the above-described problems, and can reduce the work burden on the experimenter and can objectively and accurately determine the presence or absence of radiation irradiation on a sample such as food or herbal medicine. An object of the present invention is to provide a radiation irradiation discrimination method and a radiation irradiation discrimination system.

  Therefore, as a result of intensive studies, the present inventors have released the energy accumulated by radiation irradiation in the food irradiated with radiation within a certain measurement time, and the measured light quantity gradually increases as the measurement time elapses. It has been found that the amount of light measured does not attenuate or disappear with the passage of the measurement time in foods that have not been irradiated with radiation (see FIG. 4).

  That is, in order to solve the above-described problems and achieve the object, the radiation irradiation determination method according to claim 1 of the present invention is a radiation irradiation determination method for determining the presence or absence of radiation irradiation on a sample. The amount of light emitted from the sample irradiated with is measured over time, and the presence or absence of radiation irradiation to the sample is determined based on the amount of change or rate of change of the measured amount of light.

  Further, the radiation irradiation determination method according to claim 2 according to the present invention is the radiation irradiation determination method for determining the presence or absence of radiation irradiation on food, the excitation light irradiation step for irradiating the sample with excitation light, Light emitted from the sample irradiated with excitation light in the excitation light irradiation process is detected by a photomultiplier tube through a filter that selectively transmits the light, and the amount of light detected is measured over time. The amount of change and / or rate of change of the amount of light is calculated based on the measurement step and the amount of light measured over time in the step of measuring the amount of light, and the radiation irradiation of the sample is calculated based on the calculated amount of change and / or rate of change. A radiation irradiation determining step of determining presence or absence.

  Further, the radiation irradiation determination method according to claim 3 according to the present invention is the radiation irradiation determination method according to claim 2, wherein the radiation irradiation determination step is based on the light amount measured over time in the light amount measurement step. A light quantity acquisition step of acquiring a first light quantity measured in the first time zone and a second light quantity measured in the second time zone, and a first light quantity and a second light quantity obtained in the light quantity acquisition step. Based on the difference between the average value of the first light quantity and the average value of the second light quantity based on the difference, the light quantity difference reference determination step of determining the presence or absence of radiation irradiation to the sample based on the calculated difference between the average values And further including.

  According to a fourth aspect of the present invention, there is provided the radiation irradiation determination method according to the second aspect, wherein the radiation irradiation determination step is based on the light amount measured over time in the light amount measurement step. The regression formula creating step for creating a regression formula showing the relationship between the light quantity and the time, the slope value of the regression formula is calculated based on the regression formula created in the regression formula creating step, and the calculated slope value And a regression criterion discriminating step for discriminating whether or not the sample is irradiated with radiation based on the above.

  Moreover, the radiation irradiation determination method according to claim 5 of the present invention is the radiation irradiation determination method according to any one of claims 2 to 4, wherein the excitation light irradiation step is performed by using an LED with respect to the sample. It is characterized by irradiating excitation light.

  In addition, the present invention relates to a radiation irradiation determination system, and the radiation irradiation determination system according to claim 6 according to the present invention is a radiation irradiation determination system that determines the presence or absence of radiation irradiation on a sample. Excitation light irradiation means for irradiating excitation light, and light emitted from the sample irradiated with excitation light by the excitation light irradiation means is detected by a photomultiplier tube through a filter that selectively transmits the light, A light amount measuring means for measuring the light amount of the detected light with time, a change amount and / or a change rate of the light amount based on the light amount measured with the light amount measuring means with time, and the calculated change amount and / or Alternatively, radiation irradiation determining means for determining whether or not the sample is irradiated with radiation based on the rate of change is provided.

  Further, the radiation irradiation determination system according to claim 7 according to the present invention is the radiation irradiation determination system according to claim 6, wherein the radiation irradiation determination means is based on a light amount measured with time by the light amount measurement means. A light quantity acquisition unit that acquires the first light quantity measured in the first time zone and the second light quantity measured in the second time zone, and the first light quantity and the second light quantity obtained by the light quantity acquisition means. Based on the difference between the average value of the first light quantity and the average value of the second light quantity based on the difference, the light quantity difference reference determination means for determining the presence or absence of radiation irradiation to the sample based on the calculated difference between the average values And further comprising.

  The radiation irradiation determination system according to claim 8 according to the present invention is the radiation irradiation determination system according to claim 6, wherein the radiation irradiation determination means is based on the light quantity measured with time by the light quantity measurement means. The regression formula creating means for creating a regression formula showing the relationship between the light quantity and the time, the slope value of the regression formula is calculated based on the regression formula created by the regression formula creating means, and the calculated slope value And a regression-based criterion discriminating means for discriminating whether or not the sample is irradiated with radiation based on the above.

  Moreover, the radiation irradiation discrimination | determination system of Claim 9 concerning this invention is a radiation irradiation discrimination | determination system as described in any one of Claim 6 to 8. WHEREIN: The said excitation light irradiation means is LED with respect to a sample. It is characterized by irradiating excitation light.

  In the radiation irradiation discrimination method according to claim 1 of the present invention, the amount of light emitted from a sample (food, herbal medicine, etc.) irradiated with excitation light is measured over time, and the amount of change in the measured amount of light and / or Or, because the presence or absence of irradiation of the sample is determined based on the rate of change, the burden on the experimenter is reduced, and the presence or absence of irradiation of the sample such as food or herbal medicine is objectively and accurately determined. There is an effect that can be. Here, in the TL method, since the food itself cannot be used, a pretreatment for separating and purifying the luminescent element from the food is necessary. However, the pretreatment requires a time of at least one day. Since only one to several samples can be performed at the same time, it was not always satisfactory from the viewpoint of examination time. However, since the present invention does not require sample pretreatment, the processing from the measurement of the amount of light to the determination of the presence or absence of radiation irradiation can be performed quickly, and as a result, the inspection time can be shortened. In addition, the TL method requires a cooling device that cools the photomultiplier tube and a heating device that heats the light-emitting element body, which increases the cost required for implementation. However, the present invention does not require each of these devices, so that the processing from the measurement of the light amount to the determination of the presence or absence of radiation irradiation can be realized with an inexpensive device configuration.

  Moreover, the radiation irradiation discrimination method according to claim 2 and the radiation irradiation discrimination system according to claim 6 according to the present invention irradiate a sample (food, herbal medicine, etc.) with excitation light and irradiate excitation light. The light emitted from the sample is detected by a photomultiplier tube through a filter that selectively transmits the light, and the amount of the detected light is measured over time, and the light is measured based on the amount of light measured over time. Calculates the amount and / or rate of change in the amount of light, and determines whether or not the sample has been irradiated based on the calculated amount and / or rate of change. There is an effect that it is possible to objectively and accurately discriminate whether or not the sample is irradiated with radiation. Here, in the TL method, since the food itself cannot be used, a pretreatment for separating and purifying the luminescent element from the food is necessary. However, the pretreatment requires a time of at least one day. Since only one to several samples can be performed at the same time, it was not always satisfactory from the viewpoint of examination time. However, since the present invention does not require sample pretreatment, the processing from the measurement of the amount of light to the determination of the presence or absence of radiation irradiation can be performed quickly, and as a result, the inspection time can be shortened. In addition, the TL method requires a cooling device that cools the photomultiplier tube and a heating device that heats the light-emitting element body, which increases the cost required for implementation. However, the present invention does not require each of these devices, so that the processing from the measurement of the light amount to the determination of the presence or absence of radiation irradiation can be realized with an inexpensive device configuration.

  In addition, the radiation irradiation determination method according to claim 3 and the radiation irradiation determination system according to claim 7 according to the present invention provide a first time zone (e.g., from the amount of light measured over time in the irradiation irradiation determination). The first light quantity acquired in the first measurement time and the second light quantity measured in the second time period (for example, the last measurement period or the time period immediately before the end of measurement) is acquired and acquired. The difference between the average value of the first light amount and the average value of the second light amount is calculated based on the light amount and the second light amount, and the presence or absence of radiation irradiation to the sample based on the calculated difference between the average values Therefore, it is possible to objectively and accurately determine whether or not the sample is irradiated with radiation by simple calculation.

  In addition, the radiation irradiation determination method according to claim 4 and the radiation irradiation determination system according to claim 8 according to the present invention include a light amount and a time based on a light amount measured over time in the determination of radiation irradiation. Create a regression equation that shows the relationship, calculate the slope value of the regression equation at a given point in time based on the created regression equation, and determine the presence or absence of radiation irradiation to the sample based on the calculated slope value Therefore, it is possible to objectively and accurately determine the presence or absence of radiation irradiation on the sample by mathematically expressing the phenomenon that the amount of light attenuated over time, which is confirmed in the sample irradiated with radiation. Play.

  Moreover, since the irradiation irradiation determination method according to claim 5 and the irradiation irradiation determination system according to claim 9 according to the present invention irradiates the excitation light with the LED to the sample in the irradiation of the excitation light, the excitation light There is an effect that it is easy to adjust the pulse interval (light emission time interval) when irradiating.

  Embodiments of a radiation irradiation determination method and a radiation irradiation determination system according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

  First, the whole structure of the radiation irradiation discrimination | determination system 100 of this Embodiment is demonstrated with reference to FIG. FIG. 1 is a diagram illustrating an example of the overall configuration of the radiation irradiation determination system 100. As shown in FIG. 1, the radiation irradiation discrimination system 100 is manufactured based on the light emission principle of photostimulated luminescence, and includes an OSL (Optically Stimulated Luminescence) detection unit 102, a pulse generator 104, a high voltage power source 106, a photon counter. And a radiation irradiation discrimination device 112. These devices are connected by a connection cable as shown in the figure.

  The OSL detection unit 102 irradiates the food 101 (dried food or herbal medicine) to be inspected (sample) with excitation light, and emits light (specifically, light emission) emitted from the food 101 irradiated with the excitation light. ). FIG. 2 is a diagram illustrating an example of the configuration of the OSL detection unit 102. As shown in FIG. 2, the OSL detection unit 102 includes a dark box 102a, a sample plate 102b, an LED (light emitting diode) 102c, a filter (low-pass filter, band-pass filter) 102d, a photomultiplier tube (PMT) 102e, It consists of The dark box 102a is for blocking external light, and is used for detecting the amount of light emitted from the food 101. As shown in the figure, the sample dish 102b is provided in the dark box 102a and is used for placing the food 101. Note that a stainless steel sample dish that is less affected by delayed light emission from food may be used as the sample dish 102b. Moreover, since the reduction | decrease of the photoluminescence amount resulting from the exposure to the foodstuff before a measurement is anticipated, you may put the foodstuff to be examined on the sample dish 102b in the dark box 102a in a dark room. The LED 102c is for irradiating the food 101 with excitation light. As the LED 102c, for example, LED lighting (product number “IDR-LA50 / 24IR-890-2-C01”: infrared) of IMAC (company name) may be used. The filter 102d blocks the reflected light reflected from the food due to the irradiation of the excitation light by the LED 102c, and selectively transmits the light emitted from the food. As the filter 102d, for example, a bandpass filter (product number “SWPF670”) of Asahi Spectroscopy (company name) or a bandpass filter (product number “IRC-65W”) of Mitsunobu Optical (company name) may be used. Note that the filter 102d may be composed of a single filter or a plurality of filters. The filter 102d is installed in the vicinity of the photomultiplier tube 102e as shown in the figure. The photomultiplier tube 102e detects emitted light (specifically, emitted photons) emitted from the food product 101 and transmitted through the filter 102d, and amplifies the detected emitted light (specifically emitted photons). Convert to electrical signal (analog signal). As the photomultiplier tube 102e, for example, a photomultiplier tube (product number “R329P”) manufactured by Hamamatsu Photonics (company name) may be used.

  Returning to FIG. 1 again, the pulse generator 104 is for causing the LED 102c to emit light at a predetermined time interval (pulse interval). That is, the pulse generator 104 controls the LED 102c. As the pulse generator 104, for example, a pulse power supply (product number “IDT-10S”) of IMAC (company name) may be used.

  The high voltage power source 106 controls the voltage applied to the electrode of the photomultiplier tube 102e to supply power to the photomultiplier tube 102e.

  The photon counting unit 108 converts the analog signal output from the photomultiplier tube 102e into a digital signal in consideration of a predetermined threshold. In addition, the said threshold value may be determined for every food 101, and may be determined based on the value determined with respect to the food 101 which is not irradiated with the radiation. As the photon counting unit 108, for example, a photon counting unit (product number “C3866”) manufactured by Hamamatsu Photonics (company name) may be used.

  The pulse counter 110 measures the amount of light (the number of counts per predetermined time) over time based on the digital signal output from the photon counting unit 108 (for example, at intervals of 0.1 second). As the pulse counter 110, for example, a Hamamatsu Photonics (company name) pulse counter (product number "C87747") may be used.

  The radiation irradiation determination device 112 includes at least a control unit 112A such as a CPU that comprehensively controls the radiation irradiation determination device 112 and the pulse generation device 104, and a storage unit 112B that stores various databases, tables, files, and the like. These units are communicably connected via an arbitrary communication path. In addition, the radiation irradiation discrimination | determination apparatus 112 can be comprised with information processing apparatuses, such as a personal computer marketed generally, and its attachment apparatus.

  The control unit 112A has a control program such as an OS (Operating System), a program that defines various processing procedures, and an internal memory for storing necessary data, and executes various processes based on these programs. . The control unit 112A is based on the irradiation condition determination unit 112A1 that determines the irradiation condition of the excitation light irradiated by the LED 102c (such as the time interval at which the LED 102c emits light and the illuminance of the LED 102c), and the light amount measured with time by the pulse counter 110. A radiation irradiation determination unit 112A2 that calculates a change amount and / or a change rate of the light amount and determines whether or not the food 101 is irradiated with radiation based on the calculated change amount and / or change rate.

  Here, the radiation irradiation determination unit 112A2 uses the first light amount and the second light amount measured in the first time period (for example, the initial period of measurement or the time period immediately after the start of measurement) from the light intensity measured with the pulse counter 110 over time. Based on the first light quantity and the second light quantity acquired by the light quantity acquisition unit 112A21 that acquires the second light quantity measured in the time zone (for example, at the end of measurement or just before the end of the measurement) and the light quantity acquisition unit 112A21 A light amount difference reference determination unit 112A22 that calculates a difference between the average value of the first light amount and the average value of the second light amount, and determines whether the food 101 is irradiated with radiation based on the calculated difference between the average values; Based on the amount of light measured over time by the pulse counter 110, a regression equation creation unit 112A23 that creates a regression equation indicating the relationship between the light amount and time, and a regression equation created by the regression equation creation unit 112A23 Then, the slope value of the regression equation (first derivative value of the regression equation) is calculated, and the presence or absence of radiation irradiation to the food 101 is determined based on the calculated slope value (specifically, the calculated slope value) And a regression equation criterion discriminating unit 112A24 that discriminates “irradiation” if the value is negative and discriminates “non-irradiation” if the calculated slope value is 0 or positive. The radiation irradiation determination unit 112A2 may finally determine whether or not the food 101 has been irradiated based on the determination result in the light quantity difference reference determination unit 112A22 and the determination result in the regression equation reference determination unit 112A24. Good. Further, the regression formula criterion discriminating unit 112A24 calculates a discrimination index (discrimination index) based on the regression formula created by the regression formula creation unit 112A23, and radiation irradiation of the food 101 based on the calculated discrimination index (discrimination index). The presence or absence of may be determined.

  The storage unit 112B is storage means, and for example, a memory device such as a RAM or a ROM, a fixed disk device such as a hard disk, a flexible disk, an optical disk, or the like can be used. The storage unit 112B associates the light amount value measured over time by the pulse counter 110 with the time when the light amount is measured (or the elapsed time from the time when the light amount measurement is started to the time when the light amount is measured). Remember.

  Here, the radiation irradiation determination system 100 may further include a heating device for annealing the food 101. Further, in order to increase the measurement accuracy of the light amount, a temperature control device for controlling the temperature in the dark box 102 and a cooling device for cooling the photomultiplier tube 102e (device for controlling the temperature of the photomultiplier tube 102e) are further provided. May be.

  When measuring the amount of light by the radiation irradiation discrimination system 100, the wavelength and intensity of the excitation light and the amount of light to be measured are determined so that the phenomenon that the amount of light measured from the food irradiated with radiation gradually decreases can be confirmed. It is desirable to adjust (optimize) in advance. Specifically, by conducting a preliminary experiment, an appropriate light source (LED) and an appropriate filter (a filter that blocks excitation light reflected from food and selectively transmits light emitted from food) are selected. It is desirable to adjust the pulse interval (light emission time interval) of the light source in advance.

  In the above configuration, a process of determining the presence or absence of radiation irradiation on food using the radiation irradiation determination system 100 in the present embodiment will be described with reference to FIG. FIG. 3 is a diagram illustrating an example of a process of determining whether or not the food 101 is irradiated with radiation using the radiation irradiation determination system 100.

[Step 1: Food Installation Step] The food 101 to be inspected is placed on the sample dish 102b in the dark box 102a.
[Step 2: High-voltage power source starting step] The high-voltage power source 106 is started.
[Step 3: Excitation Light Irradiation Step] In the irradiation condition determination unit 112, the irradiation condition determination unit 112A1 determines the irradiation condition of the excitation light, and transmits the determined irradiation condition of the excitation light to the pulse generator 104. Then, the pulse generator 104 activates the LED 102c based on the irradiation condition of the excitation light transmitted from the radiation irradiation determination device 112. The LED 102c irradiates the food 101 with excitation light.

[Step 4: Light quantity measurement step] The filter 102d selectively transmits the light emitted from the food 101 irradiated with the excitation light, and the photomultiplier tube 102e detects the photons of the light emitted through the filter 102d. .
[Step 5: Light quantity measurement step] The photomultiplier tube 102e amplifies the detected photons and converts them into electrical signals (analog signals).
[Step 6: Light quantity measurement step] The photon counting unit 108 converts the analog signal output from the photomultiplier tube 102e into a digital signal in consideration of a predetermined threshold. Then, the pulse counter 110 measures the amount of light over time based on the digital signal output from the photon counting unit 108 (for example, at intervals of 0.1 second), and the measured light amount value is the time when the amount of light is measured. (Or the elapsed time from the time when the measurement of the light quantity is started to the time when the quantity of light is measured) is transmitted to the radiation irradiation determination device 112 in association with it. Here, FIG. 4 shows an example of the result of measuring the light quantity over time for foods irradiated with radiation and foods that are not. FIG. 4 is a diagram illustrating an example of a result of measuring the light amount over time for foods irradiated with radiation and foods that are not. As shown in FIG. 4, in the case of food irradiated with radiation, the measured light quantity is gradually attenuated over time (the right graph in FIG. 4). On the other hand, in the case of foods that have not been irradiated with radiation, the measured light quantity does not attenuate over time, and increases slightly depending on the time zone (left graph in FIG. 4).

[Step 7: Radiation Irradiation Discrimination Step] In the radiation irradiation discrimination device 112, the control unit 112A correlates the light quantity value transmitted from the pulse counter 110 and the measurement time of the light quantity with each other in a predetermined storage area of the storage unit 112B. To store. The radiation irradiation determination device 112 calculates a change amount and / or a change rate of the light amount based on the value of the light amount transmitted from the pulse counter 110 in the radiation irradiation determination unit 112A2, and calculates the calculated change amount and / or Based on the change rate, the presence or absence of radiation irradiation to the food 101 is determined, and the determination result is stored in a predetermined storage area of the storage unit 112B.

  Here, in step 7, the radiation irradiation determination unit 112A2 uses the light amount acquisition unit 112A21 to calculate a first time zone (for example, at the beginning of measurement or immediately after the start of measurement) from the light amount value transmitted from the pulse counter 110. The measured first light amount (for example, five light amounts) and the second light amount (for example, five light amounts) measured in the second time zone (for example, the end of measurement or just before the end of measurement) are obtained, and the light amount difference reference The determination unit 112A22 calculates the difference between the average value of the first light amount and the average value of the second light amount based on the first light amount and the second light amount acquired by the light amount acquisition unit 112A21. The presence or absence of radiation irradiation on the food 101 may be determined based on the difference between the average values. Further, the radiation irradiation determination unit 112A2 generates a regression equation indicating the relationship between the light amount and the time based on the light amount value transmitted from the pulse counter 110 in the regression equation creation unit 112A23, and the regression equation reference determination unit 112A24. Then, based on the regression formula created by the regression formula creation unit 112A23, the value of the slope of the regression formula (first derivative value of the regression formula) is calculated, and the presence or absence of radiation irradiation to the food 101 based on the calculated slope value May be determined. Specifically, “irradiation” may be determined if the calculated slope value is negative, and “non-irradiation” may be determined if the calculated slope value is 0 or positive.

  As described above, the radiation irradiation determination system 100 measures the amount of light emitted from the food 101 that has been irradiated with the excitation light over time, and determines the amount of radiation irradiation to the food 101 based on the amount of change in the measured light amount. Determine presence or absence. Specifically, the radiation irradiation discrimination system 100 irradiates the food 101 with excitation light, and detects light emitted from the food 101 irradiated with the excitation light with a photomultiplier tube 102e via a filter 102d. The amount of detected light emission is measured over time, the amount of change and / or rate of change of the amount of light is calculated based on the amount of light measured over time, and the food 101 is calculated based on the calculated amount of change and / or rate of change. The presence or absence of radiation irradiation is determined. More specifically, the food product 101 is irradiated with excitation light from the LED 102c controlled by the pulse generator 104, and the light emitted from the food product 101 irradiated with the excitation light is emitted through a filter 102d to a photomultiplier tube. The amount of emitted light detected by 102e is measured over time by the pulse counter 110 via the photon counting unit 108, and the amount of change in the amount of light based on the amount of light measured over time by the radiation irradiation discrimination device 112. And / or change rate is calculated and the presence or absence of the radiation irradiation to the foodstuff 101 is discriminate | determined based on the calculated change amount and / or change rate.

  As a result, the burden on the experimenter can be reduced, and the presence or absence of radiation irradiation on the food 101 can be objectively and accurately determined. Specifically, in this system, since no external reference value is used, the presence or absence of radiation irradiation to the food 101 is objectively determined regardless of the background value of the food 101 or the luminous element content of the food 101. And accurately discriminating. Here, in the TL method, since the food itself cannot be used, a pretreatment for separating and purifying the luminescent element from the food is necessary. However, the pretreatment requires a time of at least one day. Since only one to several samples can be performed at the same time, it was not always satisfactory from the viewpoint of examination time. However, since this system does not require pre-processing of the food product 101, the processing from the measurement of the amount of light to the determination of the presence or absence of radiation irradiation can be performed quickly, and as a result, the inspection time can be shortened. In addition, the TL method requires a cooling device that cools the photomultiplier tube and a heating device that heats the light-emitting element body, which increases the cost required for implementation. However, since each of these devices is unnecessary in this system, processing from the measurement of the light amount to the determination of the presence / absence of radiation irradiation can be realized with an inexpensive device configuration.

  In the determination of radiation irradiation, the first light amount and the second time zone (for example, the end of measurement) measured in the first time period (for example, the initial period of measurement or the time period immediately after the start of measurement) from the light amount measured over time. And the second light quantity measured at the time immediately before the measurement), and the average value of the first light quantity and the average value of the second light quantity based on the acquired first light quantity and second light quantity. And the presence or absence of radiation irradiation to the food 101 may be determined based on the calculated difference between the average values. Thereby, the presence or absence of radiation irradiation to the food 101 can be objectively and accurately determined with easy calculation.

  In addition, in the discrimination of radiation irradiation, based on the light quantity measured over time, create a regression equation showing the relationship between the light quantity and time, calculate the slope value of the regression equation based on the created regression equation, The presence or absence of radiation irradiation to the food 101 may be determined based on the calculated value of the inclination. Thereby, the presence or absence of radiation irradiation to the food 101 can be objectively and accurately determined by mathematically expressing the phenomenon that the amount of light attenuated with time, which is confirmed in the food irradiated with radiation. .

  Further, in the excitation light irradiation, since the food 101 is irradiated with the excitation light by the LED 102c, adjustment of the pulse interval (light emission time interval) when irradiating the excitation light is easy.

  With reference to FIG. 5, the results of measuring the amount of light over time with the above-described radiation irradiation discrimination system 100 using powdered green juice as an inspection target will be described.

  First, it was confirmed by a TL method (EN 1788-2001) that a commercially available powdered green juice to be inspected was not irradiated with radiation. The powdered green juice was irradiated with radiation at room temperature while being shielded from light with aluminum foil. In addition, irradiation conditions are conditions that a radiation source is 185TBq cobalt 60 in Metropolitan Industrial Technology Research Institute, and a dose is 0.49 kGy-30 kGy. The amount of powdered green juice one week after the irradiation was measured over time by the radiation irradiation discrimination system 100 described above. The measurement results are shown in FIG.

  FIG. 5 is a diagram showing a measurement result when the light quantity of powdered green juice one week after irradiation is measured with the radiation irradiation discrimination system 100 over time. As shown in FIG. 5, in all powdered green juices irradiated with radiation having a dose of 0.49 kGy to 30 kGy, the light intensity was attenuated with the passage of time. On the other hand, in the powdered green juice not irradiated with radiation, the light amount did not attenuate with the passage of time, but increased slightly. As the radiation dose increased, the amount of light at the beginning of the measurement tended to increase. However, when the dose of radiation to be irradiated was 5 kGy or more, the increase in the amount of light at the beginning of the measurement tended to be saturated.

  As described above, as a result of measuring the amount of light with time using the radiation irradiation discrimination system 100, if the powder green juice is one week after the irradiation, the dose of radiation of 0.49 kGy or more has been irradiated. Irradiation / non-irradiation can be determined based on the amount and rate of change (specifically, the amount of decrease or rate of decrease). In addition, the amount of light at the beginning of the measurement tended to depend on the radiation dose. In other words, the dose dependency of the light quantity in the initial measurement was confirmed. However, when the dose of radiation to be irradiated became 5 kGy or more, the light quantity at the initial stage of the measurement tended not to depend on the dose of radiation to be irradiated. In other words, it has been confirmed that when the dose of radiation to be irradiated is 5 kGy or more, the dose dependency of the light quantity in the initial measurement tends to be saturated (weakened).

  In addition to powdered green juice, the results of measuring the amount of light over time using the above-described radiation irradiation discrimination system 100 with dry leek and chili pepper as inspection targets will be described with reference to FIGS. 6 and 7.

  First, the TL method (EN 1788) indicates that no radiation is irradiated to each of two types of commercially available powdered green juice (powdered green juice A, powdered green juice B), commercially available dried leek, and commercially available pepper. -2001). The amount of mineral that could be separated during TL measurement was 23 mg / g for powdered green juice A, 1.3 mg / g for powdered green juice B, 0.07 mg / g for pepper, and 0.008 mg / g for dried green onions. It was. And each radiation object was irradiated at room temperature in the state shielded with aluminum foil. In addition, irradiation conditions are conditions that a radiation source is 185TBq cobalt 60 in Metropolitan Industrial Technology Research Institute, and a dose is 4.6 kGy. Each inspection object after irradiation was stored for 7 days in a thermostatic bath at 25 ° C. The amount of light of each inspection object 7 days after irradiation was measured over time by the radiation irradiation discrimination system 100 described above. The measurement results are shown in FIG. Moreover, the light quantity of each non-irradiated inspection object was also measured over time by the radiation irradiation discrimination system 100 described above. The measurement results are shown in FIG.

  FIG. 6 is a diagram illustrating a measurement result when the amount of light of each inspection object 7 days after irradiation is measured over time by the radiation irradiation determination system 100. FIG. 7 is a diagram illustrating a measurement result when the amount of light of each non-irradiated inspection target is measured over time by the radiation irradiation determination system 100. As shown in FIG. 6, in all the inspection objects irradiated with radiation, the light amount at the initial measurement was different, but the light amount was attenuated as time passed. In particular, in powdered green juice A, the amount of light in the initial measurement was high. On the other hand, as shown in FIG. 7, in all non-irradiated inspection objects, the light amount did not attenuate with the passage of time, but increased slightly. Even in the non-irradiated inspection object, the amount of light at the initial measurement was different.

  As described above, as a result of measuring the amount of light over time using the radiation irradiation discrimination system 100, a powder of green juice, dried green onion, and chili pepper 7 days after irradiation, irradiated with a dose of 4.6 kGy, Irradiation / non-irradiation can be discriminated based on the change amount and change rate of the light amount (specifically, the decrease amount and the decrease rate). From this, it was suggested that if the radiation irradiation discrimination system 100 is used, it is possible to discriminate between irradiation and non-irradiation for many types of dry powder foods. In addition, as shown in FIG. 6, the light quantity at the initial stage of measurement was significantly different between powdered green juice A and powdered green juice B. This is thought to be due to the difference in the amount of minerals contained in each. That is, it is estimated that the amount of light in the initial stage of measurement in powdered green juice A was high because the amount of minerals was large.

  With reference to FIG. 8, the results of measuring the amount of light over time with the above-described radiation irradiation discrimination system 100 using pepper as an inspection object will be described.

  First, it was confirmed by a TL method (EN 1788-2001) that a commercially available pepper to be inspected was not irradiated with radiation. And the radiation was irradiated to the red pepper at room temperature in the state shielded with aluminum foil. In addition, irradiation conditions are conditions that a radiation source is 185TBq cobalt 60 in Metropolitan Industrial Technology Research Institute, and a dose is 10 kGy. After the irradiation, the pepper was divided into two groups, one group was stored in a thermostatic bath at 25 ° C. for 7 days, and the remaining group was stored in a thermostatic bath at 25 ° C. for 170 days. The amount of red pepper 7 days after the irradiation and the amount of red pepper 170 days after the irradiation were measured over time by the radiation irradiation discrimination system 100 described above. The measurement results are shown in FIG.

  FIG. 8 is a diagram showing measurement results when the irradiation intensity of the red pepper 7 days after the irradiation and the amount of the red pepper 170 days after the irradiation are measured over time by the radiation irradiation discrimination system 100. As shown in FIG. 8, the amount of light attenuated with time in the red pepper 7 days after the irradiation and the red pepper 170 days after the irradiation. The amount of light in the initial measurement of red pepper 170 days after irradiation was reduced compared to the amount of light in the initial measurement of red pepper 7 days after irradiation.

  As described above, as a result of measuring the amount of light over time using the radiation irradiation discrimination system 100, if the amount of radiation is 10 kGy and the amount of red pepper is 170 days after irradiation, the amount of change or rate of change ( Specifically, it is possible to determine irradiation / non-irradiation based on a reduction amount and a reduction rate. Moreover, as shown in FIG. 8, the amount of light at the initial measurement was different in the peppers with different storage periods. This is considered to be due to the difference in the length of the storage period (elapsed time after irradiation).

  The result of measuring the light quantity over time by the above-described radiation irradiation discrimination system 100 with the clam as the inspection object will be described with reference to FIG.

  First, a commercially available clam to be inspected was placed in a polyethylene centrifuge tube and irradiated with radiation at room temperature. In addition, irradiation conditions are conditions that a radiation source is 185TBq cobalt 60 in Metropolitan Industrial Technology Research Institute, and a dose is 0-5.0 kGy. The clams after irradiation were stored in a freezer at −18 ° C. for 10 days, and after 10 days, the clams were taken out and made into shells only. 10 days after irradiation, the clams shells (3) are placed outside on the sample plate 102b so that the excitation light strikes them, and the amount of the clams shells (outside) Measurement was performed with the discrimination system 100 over time. The measurement results are shown in FIG. Although the measurement results are omitted, the light amount of the clam shell (inner side) and the light amount of the clam digestive tract contents were also measured over time by the radiation irradiation discrimination system 100 described above.

  FIG. 9 is a diagram showing a measurement result when the light amount of the clam shell (outside) 10 days after irradiation is measured with the radiation irradiation discrimination system 100 over time. As shown in FIG. 9, the amount of light attenuated over time in all clam shells (outside) irradiated with a dose of 0.49 kGy to 5.0 kGy. Similar to Example 1, it was observed that the amount of light in the initial measurement also increased as the dose of radiation applied increased. In addition, when the clam shell (inside) and the clam digestive tract contents were examined, the measurement results were the same as when the clam shell (outside) was examined. On the other hand, in the clam shell (outside) that had not been irradiated with radiation, the amount of light increased slightly over time.

  As described above, as a result of measuring the amount of light with time using the radiation irradiation discrimination system 100, the clam shell and clam digestive tract contents 10 days after the irradiation were irradiated with a dose of 0.49 kGy or more. If so, irradiation / non-irradiation can be discriminated based on the amount of light change and the rate of change (specifically, the amount of decrease and the rate of decrease). The clam shell which is the inspection target of the present example was not able to measure the amount of light by the TL method and was outside the inspection target of the TL method, so the usefulness of the present invention is very high.

  With reference to FIG. 10, the results of measuring the amount of light over time by the above-described radiation irradiation discrimination system 100 using potato as an inspection object will be described.

  First, a commercially available potato to be inspected was irradiated with radiation at room temperature. The irradiation condition is a condition that the radiation source is 54 TBq cobalt 60 located in the National Food Research Institute, and the dose is 150 Gy (dose rate 12.4 Gy / min). Cut the potato after irradiation into a suitable size that can be measured, place the soil-attached side (skin side) upward on the sample dish 102b so that it is exposed to excitation light, and cut the potato skin The amount of light on the side was measured over time by the radiation irradiation discrimination system 100 described above. The measurement results are shown in FIG.

  FIG. 10 is a diagram illustrating a measurement result when the amount of light on the skin side of the potato after irradiation is measured over time by the radiation irradiation determination system 100. As shown in FIG. 10, the amount of light attenuated with time on the skin side of the potato irradiated with 150 Gy of radiation. On the other hand, on the skin side of the potato that was not irradiated with radiation, the amount of light did not decay with time, but increased slightly.

  As described above, as a result of measuring the amount of light over time using the radiation irradiation discrimination system 100, if the skin side of potato irradiated with 150 Gy of radiation (the side to which the soil is attached), the amount of change in the amount of light, Irradiation / non-irradiation can be determined based on the rate of change (specifically, the amount of decrease or the rate of decrease). From this, for fruits and vegetables with soil attached, even if the radiation dose to irradiate is small, discrimination between irradiation and non-irradiation based on the amount of light change and rate of change (specifically, the amount of decrease and rate of decrease) Is considered possible.

  Next, the presence or absence of radiation irradiation was determined by the following methods (1) to (3), using turmeric as a crude drug, dried leeks and dried shallot as dried vegetables, and dried ginger as a spice as inspection targets.

(1) According to the TL method (EN 1788-2001), thermoluminescence was measured for the mineral separated from the test object, and the TL ratio was calculated. Based on “EN 1788-2001”, “non-irradiation” was determined if the TL ratio was less than 0.1, and “irradiation” was determined if the TL ratio was 0.1 or more.
(2) In accordance with the PSL method, the integrated value of the light emission amount was calculated for the inspection object that was not subjected to the pretreatment performed by the TL method. PSL measurement was performed using a PSL measurement device (pulsed PSL screening system: manufactured by PPSL SURRC). Specifically, the inspection object was placed on a sample pan attached to the PSL measuring device, and the sample pan was placed on the PSL measuring device. And while irradiating a test object with the light source attached to the PSL measuring apparatus, the emitted light amount was measured for 60 second at 1 second intervals, and the integrated value was calculated. “T1 (700 counts / minute)” and “T2 (5000 counts / minute)” (EN 13751), which are thresholds used to determine the presence or absence of irradiation, adopted by Sanderson et al. For spices and dried vegetables. -2002) as a reference, if the count number (emission count number) per minute of the inspection object is less than T1, it is determined as “non-irradiation”, and the count number (emission count number) per minute of the inspection object is If T2 or more, it was determined as “irradiation”. Further, if the count number per minute (emission count number) of the inspection target is equal to or greater than T1 and less than T2, “Intermediate: an area that cannot be excluded but cannot be clearly determined (“ irradiation ”,“ non-irradiation ”) It was determined that the area of irradiation was not clearly distinguished))).
(3) Using the radiation irradiation discrimination system 100 according to the present invention, the amount of light to be inspected is measured over time, and a regression equation “y = a × Ln (x) using logarithmic regression based on the measured amount of light. + B ″ (x: elapsed time from the start of measurement (second), y: light intensity (emission count)) was created. When the coefficient “a” of the regression equation is 0 or positive, it is determined as “non-irradiation”, and when the coefficient “a” of the regression equation is negative, it is determined as “irradiation”.

  FIG. 11 shows measurement results and determination (discrimination) results when the three methods are implemented. FIG. 11 is a diagram illustrating measurement results and determination (discrimination) results when the three methods are performed. As shown in FIG. 11, in the TL method, all inspection objects are determined as “non-irradiation”. Moreover, also in the radiation irradiation discrimination system 100 according to the present invention, all inspection objects are determined as “non-irradiation”, as in the TL method, which is considered to have high determination accuracy. On the other hand, in the PSL measuring apparatus employing the PSL method, the shallot and ginger were determined as “intermediate (I)”.

  When the PSL measuring device was used, it was shown that it was determined as “intermediate (I)” even for non-irradiated inspection objects. The cause of this is considered to be that the emission count is in a considerably wide range due to the reflection of irradiation light and the influence of noise caused by the difference in color. Note that the influence of noise is, for example, that the amount of light emitted at each measurement point is integrated, and if a large noise enters at one measurement point, the integrated count increases. It is conceivable that the determination accuracy can be improved by subdividing the types of inspection objects in the PSL measuring apparatus and optimizing the threshold value for each of the subdivided inspection objects. However, considering the response at the actual site, it seems difficult to optimize the threshold value for each type of inspection object. On the other hand, the radiation irradiation determination system 100 according to the present invention clearly determines the presence or absence of radiation irradiation without using an external standard value such as a threshold based on the sign of the coefficient “a” of the regression equation. I was able to.

  With paprika and parsley as inspection objects, the presence / absence of radiation irradiation was determined by the PSL measurement apparatus used in Example 6 and the radiation irradiation determination system 100 according to the present invention.

  First, on October 17, 2004, commercially available paprika and parsley to be inspected were irradiated with radiation at room temperature. The irradiation condition is a condition that the radiation source is 54TBq cobalt 60 located in the National Food Research Institute, and the dose is 5.0 kGy and 10 kGy (dose rate 12.4 Gy / min). Irradiated paprika and parsley were stored for 6 months. After 6 months of irradiation (April 28, 2005), the PSL measuring apparatus used in Example 6 and the radiation irradiation discrimination system 100 according to the present invention measure the light quantity of the paprika and parsley after irradiation. It was. The measurement results are shown in FIGS. Note that the determination criteria in the PSL measurement apparatus and the determination method in the radiation irradiation determination system 100 are the same as those in the sixth embodiment.

  FIG. 12 is a diagram showing a measurement result when the amount of paprika 6 months after the irradiation is measured over time by the radiation irradiation discrimination system 100. FIG. 13 is a diagram illustrating a measurement result when the amount of parsley six months after irradiation is measured over time by the radiation irradiation determination system 100. As shown in FIG. 12, in the paprika irradiated with the radiation of 5.0 kGy and the paprika irradiated with the radiation of 10 kGy, the light amount was attenuated with the passage of time. On the other hand, no attenuation of the amount of light was observed in the paprika not irradiated with radiation. Further, as shown in FIG. 13, in the parsley irradiated with the radiation of 5.0 kGy and the parsley irradiated with the radiation of 10 kGy, the light amount was attenuated with the passage of time. On the other hand, no attenuation of the amount of light was observed in parsley that was not irradiated with radiation.

  FIG. 14 shows measurement results and determination (discrimination) results when the PSL measurement device and the radiation irradiation discrimination system 100 are implemented. FIG. 14 is a diagram illustrating measurement results and determination (discrimination) results when the PSL measurement device and the radiation irradiation discrimination system 100 are implemented. As shown in FIG. 14, in the PSL measuring apparatus, the paprika and parsley irradiated with the radiation of 10 kGy were determined to be “intermediate (I)”. Parsley irradiated with a radiation dose of 5 kGy was also determined as “intermediate (I)”. This cause is considered to be due to the adopted threshold as described in the sixth embodiment. On the other hand, in the radiation irradiation determination system 100 according to the present invention, the inspection target irradiated with radiation is determined as “irradiation”, and the inspection target not irradiated with radiation is determined as “non-irradiation”. In this system, since the magnitude of the integrated value is not used as a criterion, it was possible to accurately determine the presence or absence of radiation irradiation on the inspection target.

  As described above, the radiation irradiation determination method and the radiation irradiation determination system according to the present invention can determine the presence or absence of radiation irradiation to foods or herbal medicines, and can be used for food in administrations, monitoring authorities, food manufacturers, distributors, etc. It is useful for distribution management.

It is a figure which shows an example of the whole structure of the radiation irradiation discrimination | determination system. 2 is a diagram illustrating an example of a configuration of an OSL detection unit 102. FIG. It is a figure which shows an example of the process which discriminate | determines the presence or absence of radiation irradiation to the foodstuff 101 using the radiation irradiation discrimination | determination system. It is a figure which shows an example of the result of having measured the light quantity with time with respect to the foodstuff with which the radiation was irradiated, and the foodstuff which is not so. It is a figure which shows the measurement result at the time of measuring the light quantity of the powdered green juice one week after irradiation with the radiation irradiation discrimination | determination system 100 with time. It is a figure which shows the measurement result at the time of measuring the light quantity of each test object 7 days after irradiation with the radiation irradiation discrimination | determination system 100 with time. It is a figure which shows the measurement result at the time of measuring the light quantity of each non-irradiated test object with the radiation irradiation discrimination | determination system 100 with time. It is a figure which shows the measurement result at the time of measuring the light quantity of the hot pepper 7 days after irradiation and the amount of red pepper 170 days after irradiation with the radiation irradiation discrimination | determination system 100 with time. It is a figure which shows the measurement result at the time of measuring the light quantity of the clam shell (outside) 10 days after irradiation with the radiation irradiation discrimination system 100. It is a figure which shows the measurement result at the time of measuring the light quantity of the skin side of the potato after irradiation with the radiation irradiation discrimination | determination system 100 with time. It is a figure which shows the measurement result at the time of implementing three methods, and a determination (discrimination) result. It is a figure which shows the measurement result at the time of measuring the light quantity of the paprika 6 months after irradiation with the radiation irradiation discrimination | determination system 100 with time. It is a figure which shows the measurement result at the time of measuring the light quantity of the parsley 6 months after irradiation with the radiation irradiation discrimination | determination system 100 with time. It is a figure which shows the measurement result at the time of implementing a PSL measuring apparatus and the radiation irradiation discrimination | determination system 100, and a determination (discrimination) result.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Radiation irradiation discrimination system 101 Food 102 OSL detection unit
102a dark box
102b Sample dish
102c LED
102d filter
102e Photomultiplier tube 104 Pulse generator 106 High voltage power supply 108 Photon counting unit 110 Pulse counter 112 Radiation irradiation discrimination device
112A control unit
112A1 irradiation condition determination unit
112A2 Radiation irradiation discrimination unit
112A21 Light quantity acquisition unit
112A22 Light quantity difference reference determination unit
112A23 regression equation generator
112A24 regression equation criterion discriminator
112B storage unit

Claims (9)

In the radiation irradiation discrimination method for determining the presence or absence of radiation irradiation on the sample,
Radiation characterized by measuring the amount of light emitted from a sample irradiated with excitation light over time and determining whether or not the sample is irradiated based on the amount of change and / or rate of change in the measured amount of light. Irradiation discrimination method. In the radiation irradiation discrimination method for determining the presence or absence of radiation irradiation on the sample,
An excitation light irradiation step of irradiating the sample with excitation light;
The light emitted from the sample irradiated with the excitation light in the excitation light irradiation step is detected by a photomultiplier tube through a filter that selectively transmits the light, and the amount of the detected light is measured over time. A light intensity measurement process;
A change amount and / or change rate of the light amount is calculated based on the light amount measured over time in the light amount measurement step, and the presence or absence of radiation irradiation to the sample is determined based on the calculated change amount and / or change rate. Radiation irradiation discrimination process;
The radiation irradiation discrimination method characterized by including. The radiation irradiation discrimination step includes
A light quantity acquisition step of acquiring a first light quantity measured in a first time zone and a second light quantity measured in a second time zone from the light quantity measured over time in the light quantity measurement step;
The difference between the average value of the first light quantity and the average value of the second light quantity is calculated based on the first light quantity and the second light quantity acquired in the light quantity acquisition step, and the difference between the calculated average values is calculated. A light amount difference reference determining step for determining the presence or absence of radiation irradiation to the sample based on;
The radiation irradiation determination method according to claim 2, further comprising: The radiation irradiation discrimination step includes
Based on the light amount measured over time in the light amount measurement step, a regression equation creating step for creating a regression equation indicating the relationship between the light amount and time,
Based on the regression formula created in the regression formula creation step, the value of the slope of the regression formula is calculated, and based on the calculated slope value, the regression formula criteria discrimination step for discriminating the presence or absence of radiation irradiation to the sample,
The radiation irradiation determination method according to claim 2, further comprising: 5. The radiation irradiation determination method according to claim 2, wherein the excitation light irradiation step irradiates the sample with excitation light using an LED. In the radiation irradiation discrimination system that discriminates the presence or absence of radiation irradiation on the sample,
Excitation light irradiation means for irradiating the sample with excitation light;
The light emitted from the sample irradiated with the excitation light by the excitation light irradiation means is detected by a photomultiplier tube through a filter that selectively transmits the light, and the amount of the detected light is measured over time. Light quantity measuring means;
A change amount and / or rate of change of the light quantity is calculated based on the light quantity measured over time by the light quantity measuring means, and the presence or absence of radiation irradiation to the sample is determined based on the calculated change quantity and / or change rate. Radiation discrimination means;
A radiation irradiation discrimination system comprising: The radiation irradiation discrimination means is
A light quantity acquisition means for obtaining a first light quantity measured in a first time zone and a second light quantity measured in a second time zone from the light quantity measured over time by the light quantity measuring means;
The difference between the average value of the first light quantity and the average value of the second light quantity is calculated based on the first light quantity and the second light quantity acquired by the light quantity acquisition means, and the difference between the calculated average values is calculated. A light quantity difference reference determining means for determining the presence or absence of radiation irradiation on the sample,
The radiation irradiation discrimination system according to claim 6, further comprising: The radiation irradiation discrimination means is
Based on the light quantity measured over time by the light quantity measuring means, a regression formula creating means for creating a regression formula indicating the relationship between the light quantity and time;
Based on the regression formula created by the regression formula creation means, calculates the value of the slope of the regression formula, and based on the calculated slope value, the regression formula criterion judgment means for judging the presence or absence of radiation irradiation to the sample,
The radiation irradiation discrimination system according to claim 6, further comprising: The radiation irradiation determination system according to claim 6, wherein the excitation light irradiation unit irradiates the sample with excitation light using an LED.

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