JPH09211135A - Radiation counting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To correctly measure a time average, a position average or the like of an amount to be found even if a counting rate, the scanning speed of an object to be measured or the like is changed in a measuring time by providing a counting value storing means for integrating an addition value obtained by an addition value determination means. SOLUTION: An addition value is determined in accordance with a predetermined procedure in response to a object to be measured by using information of changing with elapse of time such as, for instance, a ratio of an effective measuring time and a real time and speed in which a radiation detector 2 scans the object to be measured whenever a radiation detection signal is input to an addition determination means 10, and added and stored by a counting value storing means 11. Since the addition value is determined by using the information obtained as a small minimum interval as possible, the value obtained as an integration value is accurate, if it is a measuring purpose that not the integration value on the effective measuring time of a counting rate, but the value for the measuring purpose, for instance, a real time average of the counting rate is obtained, and it can be made the real time integration of the counting rate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radiation counting device suitable for correctly measuring radiation of a measuring object.

[0002]

2. Description of the Related Art FIG. 8 shows a conventional example of a radiation counting device,
The radiation counting device 1 comprises a radiation detector 2, a preamplifier 3, a main amplifier 4, a pulse height discriminator 5 and a counting memory 6.

Here, the radiation detector 2 converts the energy of the radiation 8 into an electric signal every time the radiation 8 emitted from the radiation source 7 such as radioactive waste is detected. The preamplifier 3 amplifies the electric signal output from the radiation detector 2. The main amplifier 4 further amplifies the electric signal amplified by the preamplifier 3 and also converts it into a pulse signal having a wave height proportional to the energy of the radiation 8. At this time, if the next radiation is detected at an interval shorter than the time width of the pulse signal, the two pulse signals may overlap, the number of pulses may decrease, and the wave height may not be proportional to the energy of the radiation. Some of the main amplifiers 4 have a function of determining a pulse whose wave height is not proportional to the energy of the radiation 8 in this way as an invalid pulse. The wave height discriminator 5 discriminates whether the wave height of the output pulse of the main amplifier 4 belongs to a range divided by one or a plurality of boundaries.

If the next pulse is output from the main amplifier 4 by the end of this discrimination, the pulse height discriminator 5 ignores the pulse as an invalid pulse. Also, the wave height discriminator 5
As a result of detection of the radiation 8 by the radiation detector 2, the time period during which the pulse output from the main amplifier 4 is effective, that is, the effective measurement time or the time period during which the pulse is invalid, that is, the dead time. There is also a function of outputting a signal indicating whether or not it is, and a function of displaying the ratio of those time zones to the real time within a short time.

Generally speaking, the dead time and the effective measurement time described above will be described. In almost all detectors, the minimum time required for two events to be recorded as two separate pulses. There is. This minimum separation time is called the dead time of the counting device. Due to the random nature of radioactive decay, an event occurs shortly after the previous one, which is lost unrecorded.

Regarding the behavior of the dead time of the counting device, there are "parasitic" and "non-parasitic" types.
Two models of "parasizable" are often used.

First, the "paraffin type" will be described with reference to FIG.

When two or more input pulses overlap each other as shown in FIG. 9 (this is referred to as pulse up) and both are invalid (because the wave height information is lost), the pulse The width becomes dead time. By the second pulse input during the dead time by the first pulse,
Since the dead time is newly generated, if the dead time continues, the circuit becomes paralyzed. In this case, when the true count rate is n, the apparent count rate (measured count rate) is m, and the pulse width is τ, the following equation (1) is shown.

[0009]

[Equation 1]

On the other hand, the "non-paraffin type" will be described with reference to FIG.

When invalidating the next pulse input during the time required for AD conversion or the like of the peak value of a valid input pulse,
The dead time is a time required for AD conversion or the like, but since the invalidated second pulse is not AD converted, a new dead time does not occur and the circuit is not impaired. In this case, the following expression (2) is established.

N = m / (1-mτ) --- (2)

In both cases of the "parade type" and the "non paraffin type", m / n = effective measurement time / actual time.

The counting memory 6 is provided with a part or all of the wave height range divided by the wave height discriminator 5, that is, an integer type memory for each channel, and the count memory 6 has a main amplifier 4 and a wave height discriminator 5. In either case, the pulse determined to be effective adds 1 to or subtracts 1 from the stored value of the storage device of the channel of the wave height range discriminated by the wave height discriminator 5.
Further, the counting memory 6 is additionally provided with a memory for counting the measurement time, and counts the elapsed time from the start of measurement for either or both of the real time and the effective measurement time. The storage value of the counting storage device 6 is read by the computer 9 and is, for example, data for calculating the counting rate in each channel by dividing the counting value of each channel of the radiation detection signal by the counting value of the effective measurement time. Processing and analysis are performed.

[0015]

However, the above-described radiation counting apparatus 1 has a problem that the correct number of radiations cannot be counted as described below.

First, as described above, the conventional technique counts the number of radiations detected within the effective measurement time, and the count rate obtained by dividing the count value by the effective measurement time. Is the average count rate for the effective measurement time.
Therefore, if there is a change in the counting rate during measurement, the expected value of the time interval of radiation detection changes, and if the ratio between the effective measurement time and the actual time during a short time near each time is not constant, The count rate has different values for the average for real time and the average for effective measurement time, and it is difficult to obtain an accurate average for real time.

For example, in the case of the radiation counting apparatus 1 shown in FIG. 8, consider a case where there is a "parade" dead time of τ = 50 μsec and measurement is performed for 1000 seconds (real time).

The true count rate in the first half of 500 seconds is 1 kcp
It is assumed that the true count rate in the latter half of 500 seconds is 10 kcps (10000 pulses per second) in s (1000 pulses per second). The true average count rate in 1000 seconds is given by the following equation (3).

(1 kcps × 500 sec + 10 kcps × 500 sec) / 1000 sec = 5.5 kcps --- (3)

However, according to the actual measurement, the actual measured count value in the first half 500 seconds is expressed by the following equation (4).

[0021]

[Equation 2]

The effective measurement time is given by the following equation (5).

[0023]

(Equation 3)

The measured count value in the latter half 500 seconds is given by the following equation (6).

[0025]

(Equation 4)

The effective measurement time is given by the following equation (7).

[0027]

(Equation 5)

Therefore, in 1000 seconds, the total count value is expressed by the following equation (8).

Total count value = 475615 + 3032653 = 3508268 (counts) --- (8) Further, the total effective measurement time is represented by the following formula (9). Total effective measurement time = 476 + 303 = 779 (sec) --- (9) Therefore, the average count rate is expressed by the following equation (10). Average count rate = 3508268/779 = about 4504 = 4.5 kcps --- (10)

Average count rate obtained by the above equation (10) 4.
5 kcps is a true count rate of 5.5 kc obtained by the equation (3).
Does not match ps.

Here, considering the first half 500 seconds, the equation (11) of (real time / effective measurement time) × count value is obtained. (500/476) × 475615 = approximately 500000 −−−− (11) Further, considering the second half 500 seconds, the formula (12) of (real time / effective measurement time) × count value is obtained. (500/303) * 3032653 = about 5000000 --- (12) When the total value of these values is divided by the total measurement time (real time), the following formula (13) is obtained. (500000 + 5000000) /1000=5500=5.5 kcps --- (13)

Therefore, it coincides with the true count rate. This is because it is assumed in the above example that there is no change in the count rate during each period of 500 seconds, and it is difficult to obtain a correct count rate if the effective measurement time changes.

Secondly, in the case where the measurement object is measured while relatively scanning, if the scanning speed changes within the measurement time, the measurement time at each position of the measurement object becomes unstable, and the count is counted. A position average of count rates cannot be obtained from the average count rate obtained from the count value which is the time integral value of the rate.

That is, for example, when the count rate is proportional to the concentration, consider the relationship between the flow rate, the concentration, and the count.

First, in the first half 500 seconds, 1 l / sec
(Flow rate), 100 g / l (concentration), and 100 cps (count) were obtained, followed by 2 l / se in the latter 500 seconds.
It is assumed that c (flow rate), 200 g / l (concentration), and 200 cps (count) are obtained. In this case, the 1000-second average is 1.5 l / sec (flow rate), 150 g / l (concentration), 1
It becomes 50 cps (count), and the following formula (14) and formula (1)
5) is obtained.

True total dissolved mass = (500 × 1 × 100 + 500 × 2 × 200) = 25000 (g)-(14) Total dissolved mass based on average count rate = 1000 × 1.5 × 150 = 225000 ( g) --- (15)

Thus, the true total dissolved mass according to equation (14) does not match the total dissolved mass according to the average count rate according to equation (15).

Thirdly, when the amount to be obtained and the counting rate are not in a linear relationship, for example, when the concentration of the substance to be obtained is a function of the logarithm of the counting rate like an absorption densitometer, As is clear from the fact that the time integral value of the count rate and the time integral value of the substance to be obtained are not proportional, the amount to be obtained is calculated from the average count rate obtained from the count value which is the time integral value of the count rate. I can't get the time average of. For example, when measuring the density (concentration) of a substance by the transmission of radiation as in an X-ray photograph, the count rate R is the density (concentration) ρ
And the sample thickness t, the following equation (16) is obtained.

[0039]

(Equation 6)

In the above case, the following equations (17) and (18)
And Equation (19) and Equation (20) are obtained.

The average is (100 × 500 + 200 × 500) / 1000 = 150 --- (17)

[0042]

(Equation 7)

The average count rate for 1000 seconds is (3032653 + 1839397) / 1000 = about 4872 = 4.87 kcps ---- (20)

Equations (18), (19), and (20)
The following equation (21) is obtained by calculating ρ by

[0045]

(Equation 8) Thus the average does not match.

Therefore, the present invention provides a radiation counting apparatus capable of correctly measuring the time average or position average of the amount to be obtained even if the counting rate or the scanning speed of the measuring object changes within the measuring time. The purpose is to do.

[0047]

According to the invention of claim 1, the radiation emitted from the radiation source is detected by a radiation detector to be converted into an electric signal, and is effective as a pulse wave pulse signal proportional to the energy of the radiation. In a radiation counting device that counts and stores various radiation detection signals, every time a valid radiation detection signal is input, the addition value is determined by a predetermined procedure using information based on the radiation detection time between them. Means and a count value storage means for accumulating the added value obtained by the added value determining means. By the above means, every time a valid radiation detection signal is input, the added value is determined and integrated using information based on radiation detection during that period. As a result, even if there is a change in information based on radiation detection during the measurement time, the added value is determined for each minimum period that is each input of a valid radiation detection signal, so the influence on the count value is minimized. An accurate counting rate can be obtained.

According to the second aspect of the present invention, the radiation emitted from the radiation source is detected by the radiation detector and converted into an electric signal, and the effective radiation detection signal as a pulse wave pulse signal proportional to the energy of the radiation is counted. In the radiation counting apparatus for storing, every time an effective radiation detection signal is input, a first addition for determining an addition value of the effective radiation detection signal according to a predetermined procedure using information based on the radiation detection time therebetween. Value determining means, and first count value storage means for storing the count value of the effective radiation detection signal by integrating the addition values obtained by the first addition value determining means,
Second addition value determining means for determining an addition value for obtaining a statistical error value according to a predetermined procedure using information based on the radiation detection time during each valid radiation detection signal; A second count value storage means for storing a statistical error value for evaluating the count value obtained by the first count value storage means by integrating the addition values obtained by the second addition value determination means is provided. . By the above means, every time a valid radiation detection signal is input, the added value is determined and integrated using information based on radiation detection during that period. As a result, even if there is a change in information based on radiation detection during the measurement time, the added value is determined for each minimum period that is each input of a valid radiation detection signal, so the influence on the count value is minimized. An accurate counting rate can be obtained. Further, the statistical error value is added as an added value for each minimum period, and the obtained overall statistical error value is also accurate. Therefore, a correct evaluation can be performed on the obtained count rate.

According to a third aspect of the present invention, the radiation emitted from the radiation source is detected by the radiation detector and converted into an electric signal, and the effective radiation detection signal as a pulse wave pulse signal proportional to the energy of the radiation is counted. In the stored radiation counting device, each time an effective radiation detection signal is input, the ratio value obtained by dividing the real time between the effective radiation detection signal and the preceding effective radiation detection signal by the effective measurement time is calculated. An addition value determining means for determining the addition value,
A count value storage means for accumulating the addition values obtained by the addition value determining means is provided. By the above means, every time a valid radiation detection signal is input, the ratio obtained by dividing the real time during that period by the effective measurement time is sequentially added as an added value. In this case, even if the effective measurement time changes, it only affects the added value in the minimum period during which the effective radiation detection signal is input, and an accurate count value can be obtained. Therefore, if the obtained count value is divided by the total real time, an accurate average count rate for the total real time can be obtained.

According to a fourth aspect of the present invention, a moving substance, which is an object to be measured, is arranged between the radiation source and the radiation detector, and the radiation which has passed through the moving substance from the radiation source is detected by the radiation detector. In the radiation counting device that converts the electric radiation signal into an electric signal and stores the effective radiation detection signal as a pulse wave pulse signal proportional to the energy of the radiation, the effective radiation detection signal is input every time the effective radiation detection signal is input. An addition value determining means for determining the product of the logarithmic value of the real time and the effective measurement time between the effective radiation detection signal and the preceding effective radiation detection signal as an addition value, and the addition value obtained by this addition value determining means is integrated. And a count value storage means for storing the count value. By the means described above, the product of the real time and the logarithmic value of the effective measurement time is determined as an added value for each minimum period which is each effective radiation detection signal, and is sequentially integrated. As a result, even if there is a change in the effective measurement time or the concentration of the substance, they are added every minimum period, and since the linear quantity is counted, the error given to the count value is minimized. Therefore, when the velocity of the moving substance is constant, a real-time average of the moving substance can be accurately obtained based on the obtained count value.

According to a fifth aspect of the present invention, the radiation from the moving substance including the radiation emitting substance which is the object to be measured is detected by the radiation detector and converted into an electric signal, and at the same time, as a pulse wave pulse signal proportional to the energy of the radiation. In a radiation counter that counts and stores effective radiation detection signals, the real time between the effective radiation detection signal and the preceding effective radiation detection signal is calculated every time the effective radiation detection signal is input. An addition value determining means for determining a product of a value divided by the effective measurement time and the velocity of the transfer substance as an addition value, and a count value storing means for accumulating the addition value obtained by the addition value determining means are provided. It was done. By the above means, the product of the ratio of the real time to the effective measurement time and the velocity of the transfer substance is determined as an addition value for each minimum period which is each effective radiation detection signal, and the values are sequentially integrated. As a result, even if there is a change in the effective measurement time, it is added for each minimum period, so that the error that the effective measurement time gives to the count value is the minimum value. Therefore, it is possible to accurately obtain the position average of the transfer substance based on the obtained count value.

[0052]

1 is a block diagram of a radiation counting apparatus showing a first embodiment of the present invention.

In FIG. 1, the same reference numerals as those in FIG. 8 showing the conventional example indicate the same or corresponding portions, and the main point different from FIG. 8 in FIG. 1 is that instead of the count memory 6 and the calculator 9, addition is made. That is, the value determining means 10 and the count value storing means 11 are provided.

Here, the addition value determining means 10 uses the information that changes with the radiation detection time each time the radiation detection signal is input from the wave height discriminator 5, and adds the addition value according to a predetermined procedure. Is to determine. The count value storage means 11 has a function of accumulating the added values obtained by the added value determination means 10.

According to the above configuration, the additional value determining means 10
Each time a radiation detection signal is input to, for example, by using information that changes with time, such as the ratio of the effective measurement time to the real time, the speed at which the radiation detector 2 scans the measurement target,
The added value is determined by a predetermined procedure according to the purpose of measurement, and the added value is integrated and stored by the count value storage means 11. Therefore, the added value is determined using the information obtained by the smallest possible minimum interval, so the value obtained as the integrated value is accurate and is not the integrated value of the effective measurement time of the count rate, but depends on the measurement purpose. For example, if the purpose of the measurement is to obtain a real-time average of the counting rate, the counting rate can be a real-time integral.

It should be noted that, as a second embodiment as compared with the first embodiment, the addition value determining means 10 and the count value storage means 11 may be configured to handle the addition value and the integrated value as real numbers of the floating point system. Good.

With this configuration, each time the radiation detection signal is input to the addition value determining means 10, other information that changes with time is used to determine the addition value according to the purpose of measurement as a real number in the floating point system. The count value storage means 11 determines and accumulates the added value as a floating-point real number and stores it.
Therefore, even when it is necessary to use the added value or the integrated value as a real number for the purpose of measurement, the object of measurement can be achieved from the integrated value stored in the count value storage means 11.

In addition, in the example shown in FIG. 1 as the third embodiment as compared with the first embodiment, the addition value determination procedure in the addition value determination means 10 is performed so that the average value is calculated in real time. It may be a value at which the rate is obtained.

According to this structure, every time the radiation detection signal is input to the addition value determining means 10, other information that changes with time is used to obtain the average count rate in real time. The added value is determined, and the count value storage means 1
The addition value is integrated by 1 and stored. Therefore, the average count rate for the real time is correctly obtained from the integrated value stored in the count value storage means 11.

In addition, in the example shown in FIG. 1 as the fourth embodiment as compared with the first embodiment, the addition value determining procedure in the addition value determining means 10 is effective measurement within a short time including time. It may be added that the ratio of the real time to the time is used as the added value.

According to this configuration, every time the radiation detection signal is input to the addition value determining means 10, the ratio of the actual time to the effective measurement time within a short time including the time is determined as the addition value, and the count value is stored. The added value is integrated by the means 11 and stored. Therefore, the radiation detection number is compensated by invalidating the radiation detection signal, and the count value storage means 11 is provided.
The average count rate for real time is obtained by dividing the integrated value stored in by the total real time.

In addition, in the example shown in FIG. 1 as the fifth embodiment with respect to the first embodiment, the addition value determining procedure in the addition value determining means 10 is such that the radiation detection signal and the last valid value before that are determined. Of the actual radiation detection signal to the actual measurement time interval of the effective radiation detection signal and the last effective radiation detection signal before that effective measurement time interval A ratio may be used as the added value.

According to this configuration, every time the radiation detection signal is input to the addition value determining means 10, the time interval between the radiation detection signal and the last effective radiation detection signal before that is calculated with respect to the effective measurement time and the real time. Each is actually measured, the ratio of the actual time interval actual measurement value to the effective measurement time interval actual measurement value is determined as an additional value, and the additional value is integrated and stored by the count value storage means 11. Therefore, the reciprocal of the effective measurement time interval, that is, the integration of the count rate in real time is obtained, and the integrated value stored in the count value storage means 11 is divided by the total real time to obtain the average count in real time. The rate is obtained.

In addition, in the example shown in FIG. 1 as the sixth embodiment with respect to the first embodiment, the addition value determining procedure in the addition value determining means 10 adds up,
The value at which the average count rate for the position of the measurement object is obtained may be added.

According to this structure, each time the radiation detection signal is input to the addition value determining means 10, other information that changes with time is used to obtain the average count rate for the position of the measuring object. The added value is determined, and the added value is accumulated and stored by the count value storage means 11. Therefore, the average count rate for the position of the measurement object is correctly obtained from the integrated value stored in the count value storage means 11.

In addition, in the example shown in FIG. 1 as the seventh embodiment as compared with the first embodiment, the addition value determining procedure in the addition value determining means 10 is such that the effective measurement time within a short time including time. It is also possible to use the product of the ratio of the real time to the relative moving speed of the measurement object and the radiation detector (not shown) as the added value.

According to this configuration, every time the radiation detection signal is input to the addition value determining means 10, the ratio of the real time to the effective measurement time within a short time including the time, the relative distance between the measurement object and the radiation detector. The product of the target moving speeds is determined as an added value, and the added value is integrated by the count value storage means 11 and stored. Therefore, the radiation detection signal is invalidated and the radiation detection number and the difference in the measurement time at each position of the measurement object are simultaneously compensated, and the integrated value stored in the count value storage means 11 is used as the measurement object. Dividing by the total distance traveled by the radiation detector gives the average count rate for position.

In addition, in the example shown in FIG. 1 as the eighth embodiment as compared with the first embodiment, the addition value determining procedure in the addition value determining means 10 is such that the radiation detection signal and the last valid signal before that are added. Of the actual radiation detection signal to the actual measurement time interval of the effective radiation detection signal and the last effective radiation detection signal before that effective measurement time interval The ratio and the relative moving speed of the measurement object (not shown) and the radiation detector may be added values.

According to this structure, every time the radiation detection signal is input to the addition value determining means 10, the time interval between the radiation detection signal and the last effective radiation detection signal before that is calculated with respect to the effective measurement time and the real time. Each is actually measured, and the product of the ratio of the actual time interval actual measurement value to the effective measurement time interval actual measurement value and the relative moving speed of the measurement object and the radiation detector is determined as an additional value, and the additional value is calculated by the count value storage means 11. Accumulate and store. Therefore, the reciprocal of the effective measurement time interval, that is, the integral of the count rate over the moving distance is obtained, and the integrated value stored in the count value storage means 11 is divided by the relative total moving distance between the measurement object and the radiation detector. By doing so, the average count rate for the position is obtained.

In addition, in the example shown in FIG. 1 as the ninth embodiment with respect to the first embodiment, the addition value determining procedure in the addition value determining means 10 adds
The value at which the time average of the amount of the substance that has passed through the radiation is obtained may be used as the additional value.

According to this structure, each time the radiation detection signal is input to the addition value determining means 10, other information that changes with time is used to calculate the average of the amount of the substance that the radiation penetrates in real time. The added value for the purpose of obtaining is determined, and the added value is integrated and stored by the count value storage means 11. Therefore, from the integrated value stored in the count value storage means 11, the average of the amount of the substance through which the radiation penetrates can be correctly obtained in real time.

In addition, in the example shown in FIG. 1 as the tenth embodiment with respect to the first embodiment, the addition value determining procedure in the addition value determining means 10 is the same as that of the radiation detection signal and the previous channel. Effective measurement time interval of actual measurement of time interval of last effective radiation detection signal for effective measurement time Logarithmic value of actual measurement value and time interval of last effective radiation detection signal of same channel before radiation detection signal in real time It is also possible to use the product of the actual time interval actually measured values for the above as the added value.

With this configuration, each time the radiation detection signal is input to the addition value determining means 10, the time interval between the radiation detection signal and the last effective radiation detection signal of the same channel before that is defined as the effective measurement time. Each real time is actually measured, the product of the logarithmic value of the effective measurement time actual measurement value and the real time actual measurement value is determined as an additional value, and the additional value is accumulated by the count value storage means 11 and stored. The amount of a substance has a linear relationship with the logarithm of the intensity of the radiation that has passed through it, and the logarithmic value of the radiation count rate is integrated in real time and divided by the total real time to obtain the time average of the amount of substance. To be The reciprocal of the interval at the effective measurement time of the radiation detection signal is the count rate at that time, and the integrated value of the logarithmic value of the effective measurement time interval multiplied by the actual time interval is the time average of the substance amount. Proportional to the value with the sign inverted. Therefore, from the value obtained by inverting the sign of the integrated value stored in the count storage means 11 and dividing by the total real time, the real-time average of the amount of the substance through which the radiation penetrates can be correctly obtained.

In addition, in the example shown in FIG. 1 as the eleventh embodiment with respect to the first embodiment, the addition value determining procedure in the addition value determining means 10 integrates to transmit radiation. The value at which the average of the position of the measurement target of the substance amount is obtained may be used as the additional value.

According to this configuration, each time the radiation detection signal is input to the addition value determining means 10, the other information that changes with time is used to determine the position of the object to be measured of the amount of the substance that transmits the radiation. The addition value for the purpose of obtaining the average of is determined, and the addition value is accumulated by the count value storage means 11 and stored. Therefore, from the integrated value stored in the count value storage means 11, it is possible to easily obtain an average for the position of the amount of the substance through which the radiation penetrates.

In addition, in the example shown in FIG. 1 as the twelfth embodiment as compared with the first embodiment, the addition value determining procedure in the addition value determining means 10 is the same as that of the radiation detection signal and the previous channel. Effective measurement time interval of actual measurement of time interval of last effective radiation detection signal for effective measurement time Logarithmic value of actual measurement value and time interval of last effective radiation detection signal of same channel before radiation detection signal in real time The product of the actual measurement value of the actual time interval and the relative movement speed of the measurement object (not shown) and the radiation detector may be used as the additional value.

According to this structure, every time the radiation detection signal is input to the addition value determining means 10, the time interval between the radiation detection signal and the last effective radiation detection signal of the same channel before that is defined as the effective measurement time. Each real time is actually measured, and the product of the logarithmic value of the effective measurement time actual measurement value, the real time actual measurement value, and the relative movement speed of the measurement object and the radiation detector is determined as an additional value, and the additional value is calculated by the count value storage means 11. Is accumulated and stored. The amount of a substance has a linear relationship with the logarithm of the intensity of the radiation that has passed through it, and the value obtained by integrating the logarithmic value of the radiation count rate with the relative position of the object to be measured and the radiation detector and dividing by the total movement distance. From, a positional average of the substance amount is obtained. The reciprocal of the interval at the effective measurement time of the radiation detection signal is the count rate at that time, and the logarithmic value of the effective measurement time interval is multiplied by the moving distance at that time interval, that is, the actual time interval and the moving speed. The integrated value is proportional to the value obtained by inverting the sign of the position average of the amount of substance. Therefore, the sign of the integrated value stored in the count value storage means 11 is inverted and divided by the relative total movement distance between the measurement object and the radiation detector, and the average of the positions of the amount of the substance that transmits the radiation is calculated. Is obtained correctly.

Next, FIG. 2 is a block diagram of a radiation counting apparatus showing a thirteenth embodiment of the present invention.

In FIG. 2, the same reference numerals as those in FIG. 8 showing the conventional example indicate the same or corresponding portions, and the main point different from FIG. 8 in FIG. That is, the addition value determining means 10a and 10b and the plurality of count value storing means 11a and 11b are provided.

Here, the additional value determining means 10a, 10b
Is for determining a value to be integrated by a predetermined procedure using information that changes with the radiation detection time each time the radiation detection signal is input. Count value storage means 11
Reference characters a and 11b are for integrating the added values obtained by the added value determining means 10a and 10b.

According to the above configuration, each time a radiation detection signal is input to the plurality of addition value determining means 10a and 10b,
Using information that changes with radiation detection time, for example,
A plurality of addition values corresponding to each of a plurality of measurement purposes are determined, such as the measurement of the amount of radioactive substances and the amount of radiation absorbing substances, and the plurality of count value storage means 11a and 11b add the values for each measurement purpose. Accumulate values and store. Therefore, it is possible to simultaneously achieve a plurality of measurement purposes from the plurality of integrated values stored in the plurality of addition value determining means 10a and 10b.

As compared with the thirteenth embodiment, in the fourteenth embodiment, in the example shown in FIG. 2, the additional value determining procedure in one additional value determining means 10a is integrated to obtain another additional value. The value at which the variance of the random error of the integrated value of the added values determined by the determination means 10b is obtained may be used as the added value.

According to this configuration, each time the radiation detection signal is input to the plurality of addition value determining means 10a, 10b, the addition value corresponding to at least one measurement purpose is calculated by using the information that changes with the radiation detection time. And the added value for the purpose of evaluating the range of the random error of the integrated value of the added value,
The plurality of count value storage means 11a and 11b independently integrate and store the added values. Therefore, from the plurality of integrated values stored in the plurality of count value storage means 11a and 11b, at least one measurement purpose is achieved and at the same time,
The random error evaluation for the measurement purpose can be easily achieved.

For example, when the added value is always 1, the variance of the random error due to the fluctuation of the counting statistics is the integrated value itself as in the case of the counting by the prior art, but when it is not, the counting of one added value is performed. By separately integrating the variance of the random error due to the fluctuation of the statistics, the variance of the random error due to the fluctuation of the counting statistics can be obtained.

For example, the counting statistical error value is obtained from the following equation (22).

[0086]

[Equation 9]

Here, F '(i): the differential value of the function of the addition value between a certain effective radiation detection signal and the preceding effective radiation detection signal n: the number of sections of the effective radiation detection signal i: Signal pulse in a section of a certain effective radiation detection signal

As compared with the thirteenth embodiment, as the fifteenth embodiment, in the example shown in FIG. 2, the addition value determination procedure in one addition value determination means 10a is performed by another addition value determination means 10b. A value including the square of the determined addition value as a term may be used as the addition value.

According to this structure, the information that changes with the radiation detection time is used every time the radiation detection signal is input by at least one of the plurality of addition value determining means 10a and 10b, depending on the measurement purpose. The added value is determined, and the added value is integrated and stored by one count value storage unit 11.

Further, the other addition value determining means 10 determines the square of the addition value according to the measurement purpose as the addition value,
The other count value storage means 11 integrates and stores the latter addition value. The square root of the integrated value of the square of the added value according to the measurement purpose corresponds to the random error σ of the added value according to the measurement purpose due to the counting statistical error, as shown in the following formula (23).

[0091]

(Equation 10)

As described above, the former count value storage means 11
At least one measurement purpose can be achieved from the integrated value stored in 1., and at the same time, the random error evaluation for the measurement purpose can be easily achieved from the integrated value stored in the latter count value storage means 11.

Next, a sixteenth embodiment shown in FIG. 3 will be described.

The sixteenth embodiment is a concrete application of the first to fifth embodiments and the thirteenth to fifteenth embodiments to the present invention.

Here, the radiation counter 1C includes a measurement object 12 containing a radioactive substance, a motor 13 for rotating the measurement object at a constant speed, and a radiation 8 generated from the radioactive substance in the measurement object. The collimator 14 for squeezing and the computer 9 for data processing of the radiation counting apparatus 1 are connected.

Further, the radiation counting apparatus 1 includes the measurement object 1
2 each time the radiation detector 2, the preamplifier 3, the main amplifier 4, the wave height discriminator 5 and the radiation detection signal arranged at a position via the collimator 14 are inputted, the radiation detection signal and the last before that. Each time the radiation detection signal is input, the addition value determining means 10a having a function of determining the ratio of the effective time interval of the effective radiation detection signal to the effective measurement time interval as the addition value, and the radiation detection signal and the last before that. The addition value determination means 10b having a function of determining the square of the ratio of the actual time interval to the effective measurement time interval of the effective radiation detection signal as the addition value, the count value storage means 11a, and the count value storage means 11b.

The addition value determination means 10a, 10b and the count value storage means 11a, 11b handle the addition value and the integrated value as real numbers in the floating point system.

With the above structure, the radiation 8 generated from the radioactive substance within the range narrowed by the collimator 14 in the measurement object 12 rotated by the motor 13 at a constant speed.
Is incident. Thereby, the radiation detection signal together with the value of the wave height range discriminated by the wave height discriminator 5 is added value determining means 1.
It is input to 0a and 10b.

As shown in FIGS. 4 and 5, the addition value determining means 10a, every time the radiation detection signal is input, the real time interval with respect to the effective measurement time interval of the radiation detection signal and the effective radiation detection signal before that. Is determined as the additional value a, and the additional value a is integrated and stored in the storage device of the count value storage means 11a assigned to the wave height range.

More specifically, FIG. 4 shows the operation of each device when a radiation detection signal is input to the radiation detector 2. In the radiation detector 2, a pulse is generated only when the radiation detection signal is input. Signal is output and the preamplifier 3
Then, the waveform is converted into the illustrated waveform by the CR circuit and output to the main amplifier 4. Then, it is amplified by the main amplifier 4 as a mountain-shaped waveform shown in the figure. In this case, as shown on the left side of the figure, the peak-shaped waveforms are overlapped from the main amplifier 4 and the wave height discriminator 5
When inputting to, the wave height discriminator 5 outputs overlapping rectangular waves at the time of parade-shaped dead time as shown in the upper stage of the figure, and starts AD conversion at the time of non-parade-shaped dead time.
The pile-up is detected and interrupted as shown.

Correspondingly, the count value storage means 11a sets the clock of the effective measurement time to RUN → STOP and stops the clock counting. As a result, the addition of the effective measurement time is excluded during this period.

As shown in the bottom of the figure, when the previous effective radiation detection signal is input at time t1 and the effective radiation detection signal is input at time t2 thereafter, the real time and the effective measurement time are Equations (24) and (25) of

Real time = time t2−time t1 −−− (24) Effective measurement time = real time − {(time tc−time ta) −−−−} − (25)

Further, in the embodiment of the present invention, the addition value for the next counting and the addition value for the counting statistical error are determined in the section from the time t2 to the time t1. First, the addition value determining unit 10a determines the addition value for each section according to the following equation (26).

Addition value = (real time / effective measurement time) --- (26)

Further, the addition value determining means 10b determines the addition value for each section according to the following equation (27).

Added value = (real time / effective measurement time) squared --- (27)

More specifically, as shown in FIG. 5, the first effective radiation detection signal (first effective pulse in the figure) to the nth effective radiation detection signal (nth effective pulse in the figure) are mainly used. It is assumed that the signal is input to the amplifier 4. In this case,
In each section formed by each effective pulse and the preceding effective pulse, an addition value is determined from the following equation (28) and integrated.

[0109]

[Equation 11]

Here, H (i): real time of a certain section G (i): effective measurement time of a certain section n: number of effective pulses

In the case of the example of FIG. 5, in the first section,
Added value 14/10 = 1.4, added value 8 / in the second section
6 = 1.3, added value 15/15 = 1.0 in the third section
Is obtained. In the example of FIG. 5, numerical values are shown without a unit for the sake of explanation.

By such a calculation, the average value of the count rate in real time is obtained from the following equation (29) from the integrated value obtained by the equation (28).

[0113]

(Equation 12)

Here, H (i): real time of a certain section G (i): effective measurement time of a certain section n: number of effective pulses

On the other hand, in the addition value determining means 10b, every time the radiation detection signal is input, the square of the ratio of the real time interval to the effective measurement time interval of the radiation detection signal and the last effective radiation detection signal before that is calculated. The added value b is determined, and the added value b is accumulated and stored in the storage device of the count value storage means 11b assigned to the wave height range.

The computer 9 reads the integrated value and the actual measurement time of the count value storage means 11a and divides the integrated value by the actual measurement time to calculate the real time average of the counting rate. Also,
The computer 9 reads the integrated value of the count value storage means 11b,
By dividing the square root of the integrated value by the actual measurement time, the estimated value of the range of the counting statistical error of the real-time average of the counting rate is calculated.

As described above, according to the sixteenth embodiment, the real-time averaging of count rates and the count thereof are not affected by the fluctuation of count rates due to the non-uniformity of the distribution of radioactive substances in the measurement object 12. The estimated value of the range of the random error due to the statistical error can be accurately obtained.

Next, a seventeenth embodiment of the present invention shown in FIG. 6 will be described.

In the seventeenth embodiment, the first embodiment, the second embodiment, the eighth embodiment to the tenth embodiment are concretely applied to the present invention to flow through the pipe 16. Obtain the average concentration at the position of the element that easily absorbs radiation.
Then, under the condition that the flow velocity is constant, the time average of the amounts of the elements that easily absorb the radiation in the range sandwiched between the radiation source 7 and the radiation detector 2 is calculated.

Here, the radiation counting apparatus 1 is connected to a pipe 16 for flowing a solution 15 to be measured containing an element that easily absorbs radiation at a constant speed, and a data processing computer 9 of the radiation counting apparatus 1. ing.

The radiation counting apparatus 1 receives the radiation detector 2, the preamplifier 3, the main amplifier 4, the wave height discriminator 5 and the radiation detection signal which are arranged at a position with respect to the radiation source 7 through the pipe 16. The addition value determination means 10 and the count value storage means 11 having a function of determining the product of the logarithm of the effective measurement time interval of the radiation detection signal and the last effective radiation detection signal before that and the real time interval as an addition value every time It is composed of The addition value determining means 10 and the count value storing means 1
In the case of 1, the added value and the integrated value are handled as floating-point real numbers.

With the above configuration, when the radiation 8 generated from the radiation source 7 enters the radiation detector 2, the solution to be measured 1
The peak value of the incident wave changes according to the density of 5 or the like and is input. Therefore, only the radiation detection signal exceeding the wave height range discriminated by the wave height discriminator 5 is input to the addition value determining means 10. In the addition value determining means 10, the product of the logarithm of the effective measurement time interval of the radiation detection signal and the last effective radiation detection signal before that and the real time interval is input every time the radiation detection signal is input by the following equation (30). Is determined as the added value.

[0123]

(Equation 13)

Here, H (i): real time in a certain section G (i): effective measurement time in a certain section n: number of effective pulses

The first term of the above equation (30) will be explained. When the logarithm is taken in the above equation (16) explained in the problem to be solved by the invention, the following equation (31),
Equation (32) is obtained.

LnR = −σ · ρ · tlnRo −−−− (31) ρ = (1 / σ · t) · ln (Ro / R) = KlnG (i) −−− (32)

Here, R: Counting rate ρ: Concentration (density) t: Sample thickness Ro: Counting rate in the absence of sample σ: Absorption coefficient of sample to radiation K: Constant and the product of the second term Is used to determine the amount of substance in a certain pulse section.

The added value is accumulated and stored in the storage unit of the count value storage means 11 assigned to the wave height range. Calculator 9
Then, the integrated value and the actual measurement time of the count value storage means 11 are read, and the real-time average of the amount of the substance that easily absorbs the radiation is obtained by the following equation (33).

Real time average of substance amount = integrated value / real time −−−− (33)

This is converted into an element concentration in the solution to be measured 15 that easily absorbs radiation.

As described above, according to the seventeenth embodiment, the influence of the fluctuation of the counting rate due to the fluctuation of the concentration of the element which easily absorbs the radiation in the solution to be measured 15 and the influence of the nonlinear relationship between the amount of the absorbed substance and the count are considered. It is possible to accurately obtain the time average of the concentration of the element that easily absorbs the radiation for the purpose of measurement without receiving the radiation.

Next, an eighteenth embodiment of the present invention shown in FIG. 7 will be described.

The eighteenth embodiment is the first embodiment, the sixth to eighth embodiments, the eleventh embodiment,
The twelfth to fourteenth embodiments are specifically applied to the present invention.

The present embodiment is to obtain the average concentration of the amount of radioactive material flowing in the pipe 16 and the position of the element that easily absorbs the radiation. The means is to calculate from the position average of the counting rate of the radiation 8a generated from the radioactive substance near the detector 2, and the latter is the radiation source 7 and the radiation detector 2.
The means is to calculate from the position average of the amounts of the elements that easily absorb the radiation in the range sandwiched between.

Here, in the radiation counting apparatus 1, a pipe 16 for flowing a measurement target solution 15 containing a radioactive substance and an element which easily absorbs radiation and the measurement target solution 1 in the pipe 16 are provided.
5, a flow meter 17 for measuring the flow rate per hour and its time integration, a radiation source 7 for emitting radiation of energy different from the radioactive substance contained in the solution 15 to be measured, and a computer 9 for data processing are connected.

Further, the radiation counting apparatus 1 receives the radiation detector 2, the preamplifier 3, the main amplifier 4, the wave height discriminator 5 and the radiation detection signal which are arranged via the pipe 16 with respect to the radiation source 7. The function of determining the product of the ratio of the actual time interval to the effective measurement time interval of the radiation detection signal and the last effective radiation detection signal before that and the flow rate per time measured by the flow meter 17 as an added value for each Each time the added value determining means 10a and the radiation detection signal that it has are input, the logarithm of the effective measurement time interval of the radiation detection signal and the last effective radiation detection signal before that is measured by the real time interval and the flow meter 17. The addition value determination means 10b having a function of determining the product of the flow rate per time as an addition value and the count value storage means 11a and 11b.

The addition value determining means 10a, 10b and the count value storage means 11a, 11b are adapted to handle the addition value and the integrated value as real numbers of the floating point system.

With the above configuration, when the radiation a generated from the radioactive substance of the solution to be measured 15 and the radiation b generated from the radiation source 7 enter the radiation detector 2, the respective wave height ranges discriminated by the wave height discriminator 5 are obtained. The radiation detection signal is input to the additional value determining means 10a and 10b according to the value of.

In the addition value determining means 10a, every time the radiation detection signal is input, the ratio of the real time interval to the effective measurement time interval of the radiation detection signal and the last effective radiation detection signal before that is calculated by the flowmeter 17. The product of the measured flow rates per time is determined as the added value a, and the integrated value is obtained by the following equation (34).

[0140]

[Equation 14]

Here, H (i): real time in a certain section G (i): effective measurement time in a certain section F (i): flow rate value per time in a certain section n: number of effective pulses

Each time the radiation detection signal is input, the addition value determining means 10b calculates the logarithm of the effective measurement time interval between the radiation detection signal and the last effective radiation detection signal before that, and the effective time interval and the flow meter 17. The product of the calculated flow rates per time is determined as the added value b, and the added value b is integrated and stored in the storage unit of the count value storage means 11b assigned to the wave height range based on the following equation (35). .

[0143]

(Equation 15)

Here, H (i): real time of a certain section G (i): effective measurement time of a certain section F (i): flow rate value per time of a certain section n: number of effective pulses

The computer 9 reads the effective measurement time, which is the time integration value of the integrated value of the count value storage means 11a and the flow rate of the flow meter 17, and corresponds to the energy of the radiation generated from the radioactive substance contained in the solution 15 to be measured. The position average of the counting rate is calculated by dividing the integrated value of the channel to be divided by the time integrated value of the flow rate, and this is converted into the amount of radioactive substance in the measurement target solution 15.

Also, the computer 9 has the count value storage means 11b.
The average value of the amounts of substances in the solution to be measured 15 that easily absorb the radiation is read by dividing the integrated value of the channel corresponding to the energy of the radiation generated from the radiation source 7 by the integrated value of the flow rate. And calculate a linear quantity,
Radiation in the measurement target solution 15 is converted into an element concentration that is easy to absorb.

As described above, according to the eighteenth embodiment, the influence of the count rate fluctuation due to the non-uniformity of the distribution of the radioactive substance in the measurement object solution 15 and the absorption accompanying the fluctuation of the concentration of the element which easily absorbs the radiation are explained. Without being affected by the non-linear relationship between the amount of substance and the count and the fluctuation of the flow rate of the solution to be measured 15,
It is possible to accurately obtain the inter-position average of count rates and the position average of the radioactive substance concentration and the element that easily absorbs radiation, which are the measurement objectives.

As described above, according to the first to eighteenth embodiments of the present invention, the real-time average of the count rate, the position-average of the count rate, the real-time average of the amount of radiation absorbing substance, and the radiation It is possible to accurately obtain the position average of the amount of the substance that absorbs, and the amount to be obtained by other radiation counting.

One or more of the estimated values of the error range of these measured values can be correctly obtained without being affected by the variation of various conditions during the measurement.

[0150]

As described above, according to the invention of claim 1, each time a valid radiation detection signal is input, the addition value is determined and integrated using information based on radiation detection during that period. Even if there is a change in information based on radiation detection during the measurement time, the added value is determined for each minimum period that is each time an effective radiation detection signal is input, and the effect on the count value is minimized to ensure accurate measurement. The counting rate can be obtained.

According to the second aspect of the invention, each time a valid radiation detection signal is input, the added value is determined and integrated using information based on the radiation detection during that time, and radiation detection is performed during the measurement time. Even if there is a change in the information based on, the addition value is determined for each minimum period that is each input of a valid radiation detection signal, the influence on the count value can be minimized, and an accurate count rate can be obtained. Furthermore, the statistical error value is integrated as an added value for each minimum period, and the overall statistical error value obtained is also accurate, so that a correct evaluation can be made for the count rate.

According to the third aspect of the invention, each time a valid radiation detection signal is input, the effective time is calculated by sequentially adding the ratio obtained by dividing the real time during that time by the effective measurement time as an added value. Even if the time changes, it only affects the added value of the minimum period when the effective radiation detection signal is input, and an accurate count value can be obtained,
An accurate average count rate for all real time can be obtained.

Further, according to the invention of claim 4, the product of the logarithm of the real time and the effective measurement time is determined as an addition value for each minimum period which is each effective radiation detection signal, and is sequentially integrated. Even if there is a change in the effective measurement time or the concentration of the substance, it is added every minimum period, and since the linear amount is counted, the error given to the count value is the minimum value, and the velocity of the moving substance is constant, Based on the obtained count value, a real-time average of the transfer substance can be accurately obtained.

According to the invention of claim 5, the product of the logarithmic value of the real time and the effective measurement time and the velocity of the moving substance is determined as an added value for each minimum period which is each effective radiation detection signal. Even if there is a change in the effective measurement time, it is added every minimum period because it is integrated, and since the linear quantity is counted, the error given to the count value is the minimum value, and based on the obtained count value The position average of the moving substance can be accurately obtained.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a radiation counting apparatus showing a first embodiment of the present invention.

FIG. 2 is a configuration diagram of a radiation counting apparatus showing a thirteenth embodiment of the present invention.

FIG. 3 is a configuration diagram of a radiation counting apparatus showing a sixteenth embodiment of the present invention.

FIG. 4 is an explanatory diagram showing a first action of the radiation counting apparatus of FIG.

5 is an explanatory diagram showing a second action of the radiation counting apparatus of FIG.

FIG. 6 is a configuration diagram of a radiation counting apparatus showing a seventeenth embodiment of the present invention.

FIG. 7 is a configuration diagram of a radiation counting apparatus showing an eighteenth embodiment of the present invention.

FIG. 8 is a configuration diagram showing a conventional radiation counting apparatus.

FIG. 9 is an explanatory diagram showing a first dead time in detecting radiation.

FIG. 10 is an explanatory diagram showing a second dead time in detecting radiation.

[Explanation of symbols]

 1 Radiation Counter 2 Radiation Detector 3 Preamplifier 4 Main Amplifier 5 Wave Height Discriminator 6 Counting Memory 7 Radiation Source 9 Calculator 10 Addition Value Determining Means 11 Counting Value Storage Means 16 Piping 17 Flowmeter

Claims (5)

[Claims] 1. A radiation counting device which detects radiation emitted from a radiation source by a radiation detector and converts it into an electric signal, and counts and stores an effective radiation detection signal as a crest pulse signal proportional to the energy of the radiation. In addition, each time an effective radiation detection signal is input, an addition value determining means for determining an addition value by a predetermined procedure using information based on the radiation detection time between them, and an addition value determining means A radiation counting device, comprising: a count value storage unit that accumulates added values. 2. A radiation counting device which detects radiation emitted from a radiation source by a radiation detector and converts it into an electric signal, and counts and stores an effective radiation detection signal as a pulse pulse signal proportional to the energy of the radiation. In the above, each time an effective radiation detection signal is input, first addition value determining means for determining an addition value of the effective radiation detection signal according to a predetermined procedure using information based on the radiation detection time therebetween, First count value storage means for accumulating the addition values obtained by the first addition value determination means and storing the count value of the effective radiation detection signal, and for every input of the effective radiation detection signal Second addition value determining means for determining an addition value for obtaining a statistical error value by a predetermined procedure using information based on the radiation detection time, and the second addition The radiation counting device, characterized by comprising a second count value storing means for storing the statistical error value to evaluate the count value obtained by said first count value storing means by integrating the added value obtained by the determining means. 3. A radiation counting device which detects radiation emitted from a radiation source by a radiation detector and converts it into an electric signal, and counts and stores an effective radiation detection signal as a crest pulse signal proportional to the energy of the radiation. In each case, every time a valid radiation detection signal is input, the ratio value obtained by dividing the real time between the valid radiation detection signal and the preceding valid radiation detection signal by the effective measurement time is determined as the added value. A radiation counting apparatus comprising: an addition value determining means; and a count value storage means for accumulating the addition values obtained by the addition value determining means. 4. A moving substance, which is an object to be measured, is arranged between a radiation source and a radiation detector, and radiation transmitted from the radiation source through the moving substance is detected by the radiation detector to generate electricity. In a radiation counting device that converts the signal into a signal and counts and stores the effective radiation detection signal as a pulse wave pulse signal proportional to the energy of the radiation, each time the effective radiation detection signal is input, the effective radiation detection signal and its An addition value determining means for determining the product of the logarithmic value of the real time and the effective measurement time between the preceding effective radiation detection signal as an addition value, and a meter for integrating the addition value obtained by this addition value determining means. A radiation counting device comprising: a numerical storage means. 5. A radiation detection signal which is effective as a pulse wave signal proportional to the energy of the radiation, as well as detecting radiation from a moving substance including a radiation emitting substance which is an object to be measured by a radiation detector and converting it into an electric signal. In the radiation counting device that counts and stores the effective radiation detection signal, the real time between the effective radiation detection signal and the preceding effective radiation detection signal is divided by the effective measurement time each time the effective radiation detection signal is input. Addition value determining means for determining the product of the calculated value and the velocity of the transfer substance as an addition value,
A radiation counting apparatus comprising: a count value storage unit that integrates the addition values obtained by the addition value determination unit.