JPH11326523A - Digital counting rate meter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a digital counting rate meter whose constitution is simple and whose response is fast. SOLUTION: A counter part in which the generation number of pulses to be measured is acquired as counted-value information over the sampling time decided for every counting cycle is provided. A preprocessing part 21 in which time-series information on the counted-value information is given to every counted-value information in every counted-value information is provided. A memory part 23 in which the counted-value information with the time-series information is stored and in which prescribed counted-value information is read out by designating time-series information is provided. On the basis of the time-series information, counted-value information is read out sequentially from new counted-value information so as to be retrospective. A counting rate is computed on the basis of the integrated time in which the counted value of every counted-value information becomes a set value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital counting rate meter used for, for example, a radiation monitoring device.

[0002]

2. Description of the Related Art As a digital counting rate meter of this type, there is, for example, an apparatus shown in FIG. In FIG. 15, 10
0 is a counter for counting the number of pulses from the pulse source to be measured generated at a predetermined sampling time for each sampling period to obtain count value information of the pulse source to be measured, and 200 calculates this count value information. This is a calculator for calculating the count rate. In the arithmetic processing in the arithmetic unit 200, a time-series label is attached to each count value information sent from the counter 100 at each sampling period so that the time series in which the count value information is obtained can be recognized and temporarily stored in a memory. The count value information to which the time-series information is added is taken out of the memory sequentially from the new count value information of the time-series label in each operation cycle, and the sampling time and the count value are integrated. An integration count value N at which the integration time becomes the set value T is determined, and the integration count value N is divided by the integration time T to determine a count rate n. The set value of the integration time is set to a value determined by the following equation so as to have a desired standard deviation σ with respect to a normal background count rate. Set value of integration time = 1 / (σ ² × normal background average count rate)

[0003]

The conventional digital counting rate meter is constructed as described above, and since the counting rate is obtained by using the integrated count value in the preset integration time, the statistical fluctuation of radiation is obtained. However, the output has a characteristic of a Gaussian distribution centered on the average count rate, but there is a problem that the response is slow since the output responds to the rapid change of the input in the integration time.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and it is an object of the present invention to obtain a digital count rate meter having a quick response by a simple operation and to obtain an average count in a low count rate area including a normal background count rate. A digital count rate meter that maintains Gaussian distribution characteristics centered on the rate and responds quickly in the high count rate area including the high alarm set point, and the standard deviation of the count rate is constant regardless of the count rate. Another object of the present invention is to provide a digital counting rate meter which prevents false alarms caused by transient burst input such as cosmic rays or noise.

[0005]

A digital count rate meter according to the present invention includes a counter section for collecting the number of pulses to be measured as count value information over a sampling time determined for each sampling period, A preprocessing unit for adding the time series information of the count value information to each count value information, and a memory for storing the count value information with the time series information and reading out the predetermined count value information by specifying the time series information Unit and, based on the time-series information, read out the count value information sequentially from the latest count value information, and calculate the count rate from the integrated value of the count value of each count value information and the integrated value of the sample time. And an arithmetic processing unit.

[0006] The arithmetic processing unit sequentially integrates the count value and the sample time starting from the latest count value information of the time-series information, and calculates the sample time of the sample value at which the integrated value of the count value becomes a preset set value B. From the integrated value Tb, B / Tb
Is obtained as the counting rate. Further, the setting value B can be variably set. Also,
An A-type calculation in which the count value and the sample time are sequentially integrated retroactively from the latest count value information, and the count rate na is calculated as Na / A from the integrated value Na of the count value at which the integrated time reaches a preset value A. A processing unit, and a B-type operation processing unit for obtaining the count rate nb as B / Tb from the integrated value Tb of the sample time at which the integrated value of the count value becomes the preset set value B, wherein the count rate n is the set value C A in the following cases
When the count rate n is greater than or equal to the set value C, the calculation result by the type calculation processing section is output as the calculation result by the B type calculation processing section.

The arithmetic processing unit sequentially integrates the count value and the sample time starting from the latest count value information of the time-series information, and calculates the integrated time by a preset value A.
From the integrated value Na of the count value, the count rate na = Na /
A type arithmetic unit for calculating A, and the difference between the negative feedback count value calculated by the product of the count rate in the immediately preceding arithmetic cycle and one unit of sample time and the count value obtained from the latest count value information is algebraically calculated. And a D-type operation unit for calculating the integrated count value or the count rate so that the standard deviation of the fluctuation of the count rate becomes the set value D. A when set value C or less
The output of the type operation unit is set to the count value C by the type A operation unit.
In the above case, the output of the D-type operation unit is output as the count rate.

Further, the conversion circuit sets the integrated count value to M and γ = 2σ ² (σ is the standard deviation of the fluctuation of the count rate), and calculates the integrated count value by the relational expression of count rate N (M) = 2 ^{rM / ln2.} Is converted to a counting rate by an arithmetic circuit.

In addition, the count value and the sample time are sequentially integrated retroactively from the latest count value information of the time-series information, and the integrated value Na of the count value at which the integrated time reaches a preset value A is used to calculate the count rate na = A / A calculation unit for obtaining Na / A, an up-down counter for applying a pulse to be measured to an addition terminal, applying a negative feedback pulse to a subtraction terminal, and algebraically integrating the difference to obtain an integrated count value; A pulse generator for inputting an integrated count value of a down counter and generating the negative feedback pulse at a count rate corresponding thereto, and a count rate from the integrated count value such that a standard deviation of fluctuation of the count rate becomes a set value E. And an E-type operation unit having an operation circuit for calculating the A. When the count rate of the A-type operation unit is equal to or less than the set value C, the output of the A-type operation unit is output. For more is obtained so as to output the output of the E-type operation section, as a count rate. Equipped with a burst elimination function, which suppresses fluctuations in the normal background coefficient ratio, responds quickly in the high counting rate region including the high alarm set point, and provides bursty transients such as cosmic rays and noise. It operates stably with respect to input.

The set values A, C, D, E, G, H,
J variable means is provided so that the operation state can be optimally set according to the situation. Further, the apparatus is provided with setting means for setting the set value C to be different values when the count rate rises and when the count rate falls, and setting the value C when the count rate falls to be smaller than the value C when the count rate rises. Further, the count value information having a count value equal to or greater than the set value is captured by the burst determination unit within a set period, and is excluded from the count value integration. This eliminates abnormal count values as burst pulses and prevents malfunctions due to bursty transient noise.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. 1, 2, and 3. FIG. 1 and 2, reference numeral 1 denotes a counter unit that counts the number of pulses of a pulse signal to be measured input to an input terminal 11, and 2 calculates a counting rate using a pulse signal sent from the counter unit 1, and And a control signal unit 3 for supplying a control signal to the counter unit 1 and the arithmetic processing unit 2. The arithmetic processing unit 2
Before processing into count value information by setting a count value of a pulse signal obtained by sampling at a predetermined time width at a predetermined sampling period, a time at which the sampling is performed and time information relating to the sampling time width are set. The processing unit 21 accumulates the individual count value information,
A memory section 22 for reading out specified count value information from the outside; for each predetermined operation cycle, the count value information stored in the memory is taken out retrospectively from the latest count value information in order to integrate the count value The calculation unit 23 is configured to calculate the sample rate of each piece of count value information at a preset value of the count value, and calculate the count rate.

FIG. 3 is an explanatory diagram of the memory section 22. a
Is an address number assigned to each memory, b is time information relating to an acquisition time of each count value, and c is information such as a count value and a sample time. The count value information is constituted by b and c. One set of count value information is stored in one address for each sampling time. Then, in accordance with an instruction from the arithmetic processing unit 23, the count value information accumulated at the newest address is traced back to the past in chronological order and read out, and used for the count rate arithmetic processing.

Next, the operation will be described. Arithmetic unit 23
Reads the count value information from the memory unit 22 in retrospectively from the latest count value information in each set calculation cycle, and integrates the respective count values. When the integrated count value N reaches the set value B, the integrated value Tb of the sampling time Δt for obtaining each count value is obtained. The counting rate is obtained as n = B / Tb. The integrated count value is controlled using the set value B as a target value for each calculation cycle.

Next, the response characteristics when the number of input pulses increases stepwise in the first embodiment will be described. In the conventional calculation method with a constant integration time, the response output rises in proportion to time and becomes the same as the input at the set value A of the integration time, whereas in the first embodiment, the normal background counting rate The exponential rise as shown in the following equation gives a fast-response counting rate meter. FIG.
The outline is shown below (solid line: in the case of the first embodiment, broken line: a conventional example (integrated time is constant)).

[0015]

(Equation 1)

It is known that the standard deviation σ of the count rate n when an irregular pulse such as a radiation event is measured using a digital count rate meter is expressed by the following equation. σ = (1 / 2nτ) ^1/2 where n: count rate, τ: time constant In the arithmetic unit 23 according to the first embodiment, the integrated count value N
Is the set value B, the integrated value T of the sampling time is obtained, and the count rate n is calculated and output from B / T. Therefore, the standard deviation σ of the count rate n is σ = 1 / B ^{1 / 2,} which has a constant value regardless of the count rate n.

The integrated value T of the sampling time at which the integrated count value N is obtained changes with the change of the integrated count value in each calculation cycle. It also changes by changing the set value A of the integration time. Further, since the calculation unit according to the first embodiment has a relationship of σ = 1 / B ^1/2 , by changing the setting of the set value B of the integrated count value, it is possible to obtain the standard deviation value σ of the count rate. Value can be set to

Further, the integration time corresponds to twice the time constant τ as shown in the following equation, and is inversely proportional to the counting rate n. T = 2τ = 1 / (nσ ² )

Embodiment 2 Next, a second embodiment will be described. FIG. 5 is a configuration diagram according to the second embodiment.
In FIG. 5, components denoted by the same reference numerals as those in FIGS. 1 and 2 indicate components having the same contents or functions. The arithmetic processing unit 23 includes two types of arithmetic units, an A-type arithmetic unit 23A and a B-type arithmetic unit 23B. The A-type operation unit 23A performs integration until the integration time reaches the set value A, and the integrated count value Na at that time.
Which is determined as a count rate n = Na / A from
The B-type operation unit 23B obtains the integrated time Tb at which the integrated count value becomes the set value B as in the operation unit of the first embodiment, and obtains the count rate n = B / Tb. 2
Reference numeral 4 denotes an output switching control unit that switches and outputs one of the count rates obtained by the A-type operation unit 23A and the B-type operation unit 23B according to conditions.

In the first embodiment, the integration time is determined so that the integration count value becomes the set value B, and the count rate is calculated. In the low count area including the normal background count rate, the count rate calculated by the integrated count number so that the integrated time becomes the set value A is reached, and when the count rate reaches the high count rate area including the high alarm set point, the first embodiment is performed. The count rate calculated and calculated from the integration time at which the same integration count value becomes the set value B is output.

Next, the operation will be described. The A-type operation unit 23A is an operation unit that performs the operation of the constant integration time method. In each operation cycle, the count value information is read out from the memory unit 22 sequentially retroactively from the latest count value information at that time to the count value. And the sample time, and the integrated value of the sample time is used to determine the count rate from the integrated count value of the predetermined set value A and the integrated time. The B-type operation unit 23B is an operation unit that performs an operation of a constant accumulated count value method, and reads out the respective count value information from the memory unit 22 sequentially from the latest count value information at that time for each operation cycle and counts the count value. And the sample time, and the count rate is determined from the integrated time and the integrated count value when the integrated count value is the predetermined set value B. The output switching control unit 24 includes an A type operation unit 23
When the counting rate by A is equal to or less than the set value C, the A-type operation unit 23A
Is output to the output terminal 13 as count rate data. When the count rate is equal to or more than the set value C, the output of the B-type operation unit 23B is guided to the output terminal 13. When the count rate of the B-type operation unit 23B becomes equal to or less than the set value C, the output of the A-type operation unit 23A is guided to the output terminal 13.

More specifically, the arithmetic unit 23 sequentially reads out the latest count value information and the count value information that goes back chronologically in the past from the memory unit 22 for each operation cycle, and integrates the sample time with the set value. The respective count values are integrated until A is reached to obtain an integrated count value. A count rate is determined from the integrated count value and the integrated value of the sampling time, and if the count rate is equal to or less than the set value C, the count rate data is output. If the value is equal to or greater than the set value C, the integrated value of the sample time until the integrated count value becomes equal to the set value B is obtained, and the count rate is obtained from the integrated count value and the integrated value of the sample time. Output as

As described above, as shown by the solid line in FIG. 6, the output characteristic has a characteristic that the integration time is constant at a low count rate, and has a characteristic that the integration count value is constant at a high count rate. As a result, at a normal background count rate, the count rate has a Gaussian distribution characteristic centering on the average count rate, and at a high count rate, the characteristic has a fast rise. The broken line shows the case where the integration time is constant.

In the second embodiment, the operation unit 23
Is divided into a fixed integration time method and a fixed integration count value method, and both types of calculations are performed at the same time, and the output that meets the condition is led to the output terminal. It is also possible to execute one arithmetic processing of the constant method and the integrated count value constant method first, and to switch the arithmetic processing method to the other depending on whether the count rate of the measurement result is equal to or less than the set value. If this method of arithmetic processing is adopted, there is a problem that the arithmetic processing method at that time cannot be determined unless one of the arithmetic processing is executed for each arithmetic cycle, but the predetermined count value information is quickly stored in the memory unit 22. By performing the arithmetic processing by taking in the arithmetic processing unit 23 from
The delay caused by the above trial does not substantially hinder the trial.
In this case, a single set of calculation units may be prepared by switching the integrated value of the calculation unit between the time reference and the count value reference.

Embodiment 3 In the third embodiment, the negative feedback count value (the product of the count rate in the previous calculation cycle and the extraction time Δt of one piece of count value information) is calculated from the latest count value of the current count value information in each calculation cycle.
Is subtracted, the count value of the difference is algebraically integrated, the integrated count value is obtained, and the count rate is obtained.

Embodiment 3 will be described below with reference to FIG. In FIG. 7, components denoted by the same reference numerals as those in FIGS. 1, 2 and 5 indicate components having the same contents or functions. The arithmetic processing unit 23 includes an A-type arithmetic unit 23A and a D-type arithmetic unit 23D that functions as follows. A type operation unit 2
3A performs integration until the integration time reaches the set value A, and calculates the count rate na = Na / A from the integration count value Na at that time.
The D-type operation unit 23D
Is algebraically integrating the count value obtained by subtracting the product of the count rate and the sample time (negative feedback count value) in the immediately preceding calculation cycle from the count value of the latest count value information in each calculation cycle, The counting rate nd is calculated from the integrated count value Nd. When the count rate of the A-type operation unit 23A is equal to or less than the set value C, the output of the A-type operation unit 23A is switched to the D-type operation unit 23D when the count rate reaches the set value C. However, the calculation result is not output as it is, but is converted and output so that the fluctuation is constant regardless of the count rate nd, and is output.

Next, an example of the configuration of the D-type operation unit 23D will be described with reference to FIG. 23D1 is a subtraction circuit for subtracting the negative feedback count value (the product of the count rate nd and the sampling time Δt in the previous operation cycle) from the count value fetched from the memory unit 22, and 23D2 is a subtraction circuit 23D1.
The integration circuit 23D3 calculates the count rate nd based on the integration result so that the fluctuation becomes constant.

Next, the operation will be described. At each operation cycle, the negative feedback count value (the product of the count rate and the sampling time in the previous operation cycle) is subtracted from the count value of the latest count value information in the calculation cycle, and an algebraically integrated count value is obtained. The counting rate is determined. This corresponds to a system forming a closed loop, and the feedback gain G of the closed loop in this calculation is represented by the following equation. G = 1 / r = dn (M) / dM where Nd = M, nd = n (M) In order to keep the standard deviation σ constant, n (M) · τ
Must be set to a constant value γ, and n (M) is given by the following equation. 1 / {n (M) · τ} = {1 / n (M)} · {dn
Assuming that (M) / dM｝ 1 / {n (M) γτ｝ = γ, dn (M) / dM = γ ・ n (M) Since a function that becomes a constant multiple when differentiated is represented by an exponential function,

[0029]

(Equation 2)

In the expansion of the above equation, the set value D is, for example, D
= Γ, and the standard deviation of the fluctuation is constant regardless of the count rate nd. When the output is switched from the count rate na to the count rate nd, for example, an initial value of the integrated count value Nd is obtained from the previous count rate na immediately before the switch by the following equation. Nd = M = ln (na) / (2σ ² )

As described above, according to the third embodiment, similarly to the second embodiment, in the low measurement area including the normal background count rate, the Gaussian distribution centering on the average count rate is obtained.
In a high measurement area including an alarm set point, a digital count rate meter that responds at high speed can be realized. Also, the number of calculations is smaller than that of the second embodiment, so that there is a feature that the calculation time is short.

Embodiment 4 FIG. In the fourth embodiment, an up-down counter that applies a pulse to be measured to an addition terminal, applies a negative feedback pulse to a subtraction terminal, algebraically adds the difference, and outputs an integrated count value for each calculation period, There is a pulse generator that outputs the negative feedback pulse according to the count value and adds the pulse to the subtraction terminal of the up / down counter, and calculates the count rate from the integrated count value. However, instead of outputting the calculation result as it is, the fluctuation is kept constant regardless of the magnitude of the count rate nd.
The calculation described below is performed and output.

Embodiment 4 will be described below with reference to FIG. In FIG. 9, components denoted by the same reference numerals as those in FIGS. 1 and 2 have the same contents or functions. 25 is an up-down counter that has an addition terminal for inputting a pulse to be measured from the input unit 11 and adds it and a subtraction terminal for adding a negative feedback pulse, and algebraically integrates the difference between the number of pulses input to the addition terminal and the subtraction terminal. This is a pulse generator that generates a negative feedback pulse having a count rate according to the integrated count value for each calculation cycle. 2
Reference numeral 3E1 denotes an arithmetic circuit E for calculating the count rate ne from the integrated count value Ne. The E-type arithmetic unit 2 includes an up-down counter 25, a pulse generator 26, and an arithmetic circuit 23E1.
3E.

Next, the operation will be described. With the up / down counter, the pulse to be measured from the input section is added to the addition terminal and the negative feedback pulse from the pulse generator is added to the subtraction terminal for each calculation cycle, and the count value of the difference between them is algebraically integrated and integrated. A value is obtained, and a counting rate is obtained from the integrated count value by the arithmetic circuit E. Also in this case, instead of outputting the calculation result by the E-type calculation unit as it is, the conversion is performed in the same way as in the third embodiment so that the fluctuation is constant regardless of the magnitude of the count rate ne, and the conversion result is output. ing.

Embodiment 5 FIG. In the fifth embodiment, the switching between the low count rate area and the high count rate area is provided with a hysteresis characteristic to stabilize the switching.

The fifth embodiment will be described below with reference to the flowchart of FIG. First, the operation flag is initialized to 0 by a system reset, and the operation is started. When the calculation flag is 0, the calculation is performed in a calculation method with a constant integration time,
It outputs the count rate n1 of the arithmetic method with a constant integration time. When the calculation flag is 0 and the count rate n1 is equal to or more than the set value C1,
The calculation flag is inverted to 1, the calculation is performed by the standard deviation constant method, and the count rate n2 in the standard deviation constant method is output. When the calculation flag is 1 and the count rate n2 becomes equal to or less than the set value C2, the calculation flag is inverted to 0, and the calculation is performed in a calculation method with a constant integration time. Here, C2 <C1 is set. As described above, by switching between the calculation method with the constant integration time and the constant standard deviation method with hysteresis, the switching can be performed stably.

Embodiment 6 FIG. In the sixth embodiment, when integrating the count value, the integration is performed by excluding the count value equal to or greater than the set value within a set period, and an abnormally large count value is excluded as a burst pulse. And has a burst exclusion function. Embodiment 6 will be described with reference to FIG. In FIG. 11, the same reference numerals as those in the previous figures perform the same or equivalent functions. Reference numeral 27 denotes a determination unit which determines whether or not the pulse signal from the counting unit 21 exceeds a preset count value, and if it exceeds the value, attaches a determination mark to the memory unit 22 as abnormal and sends it to the memory unit 22.

Next, a specific operation will be described. Judgment unit 27
The pulse signal which has been determined to be abnormal and has been given the judgment mark 1 is
Like the other normal pulse signals, the pre-processing unit performs pre-processing for adding the time at which the sampling was performed and the information on the time at which the sampling was performed, and the pre-processing unit sends each piece of count value information to the memory unit 22. It is stored.
Next, in the course of integration by the arithmetic unit 23, the addition is performed under the following conditions or the data is omitted from the addition. That is, a predetermined number F of past count value information is checked in order from the newest count value information in each calculation cycle, and if the count value information with the determination flag 1 is less than G set values, In some cases, counting is performed by omitting the count value information with the determination flag 1 to obtain a count rate. If the count value information with the determination flag 1 exceeds the set value G, it means that it is already in a state where it cannot be regarded as an abnormal value, so that subsequent integration is performed including the count value information of the determination flag 1. Note that the integration including the count value information of the determination flag 1 is continued for a predetermined period H from the time when the count value information of the determination flag 1 becomes equal to or more than the specified value G, and then recovered to recover the original monitoring state. Take a way to operate with.

The set value J of the count value which is regarded as an abnormal value is set by the following equation, for example. Set value J = n × ΔT + k × (n × ΔT) ^1/2 n: count rate at normal time k: 4 to 6 in consideration of the probability of occurrence of false alarm. The set value F is set as follows in consideration of the discrete burst. Set value F> Set value A (integrated time) / 1 unit sample time (ΔT) Set value G is set assuming a burst time. Set value G ≧ burst time / 1 unit sample time (ΔT) The burst time is set to 10 seconds, for example, assuming cosmic rays. The set time H is set to a sufficiently long time, for example, 24 hours, in order to make noise due to a failure in the device obvious.
Set to time.

As described above, according to the sixth embodiment, it is possible to prevent a malfunction due to bursty transient noise. In particular, this is effective when the normal background count rate is as low as several cpm as in the case of the N-16 monitor and countermeasures against bursty high energy cosmic rays are required. It is also effective for countermeasures against external noise.

Embodiment 7 FIG. In the seventh embodiment, the burst removal function of the sixth embodiment is added to the first to third embodiments. FIG. 12 shows the configuration diagram.
Components denoted by the same reference numerals as those in FIGS. 1, 2, 5, 7, and 11 have the same or equivalent functions. In the configuration of the seventh embodiment, the fluctuation of the normal background count rate is suppressed, and the response is fast in the high count rate area including the high alarm set point, and the apparatus operates stably even with bursty transient noise. A digital counting rate meter can be realized.

Embodiment 8 FIG. In the eighth embodiment, the burst removing function of the sixth embodiment is added to the fourth embodiment. FIG. 13 shows the configuration diagram. 1, 2, 5,
Those denoted by the same reference numerals as those in FIGS. 7, 9 and 11 have the same or equivalent functions.

Embodiment 9 Embodiment 9 relates to a function of preventing a false alarm due to a test pulse.
FIG. 14 shows the configuration of the ninth embodiment. In FIG.
11 have the same or corresponding functions. Reference numeral 28 denotes a test signal source for checking the counting rate by adding a wide range of pulse signals. When the signal from the signal source 28 is injected by the determination unit 27, the determination flag is set to 0.
Keep it. With this configuration, even when a test pulse is input from a pulse signal source having a wide range of count numbers, malfunction can be prevented due to a sudden change in the test pulse during the test.

[0044]

As described above, according to the digital counting rate meter according to the present invention, the counter section that collects the number of pulses to be measured as count value information over the sampling time determined for each sampling period, For each count value information, a pre-processing unit for adding the time series information of the count value information to each of the count value information, and storing the count value information with the time series information and specifying the time series information by specifying the time series information A memory unit for reading out count value information, and, based on the time-series information, reading out count value information sequentially from the latest count value information, and integrating the integrated value relating to the count value of each count value information and the sample time thereof. And a calculation processing unit that calculates the count rate from the values. There is an effect that can be computed count rate retrieves the value information.

According to the digital counting rate meter according to the present invention, the arithmetic processing section integrates the count value and the sample time of each count value information sequentially from the latest count value information of the time series information. , The integrated value T of the sample time when the integrated value of the count value becomes the preset value B.
Since the count rate is obtained as B / Tb from b, there is an effect that a digital count rate meter with a quick response can be configured.

According to the digital counting rate meter according to the present invention, since the set value B can be variably set, the standard deviation of the counting rate can be set to a desired value.
Further, according to the digital counting rate meter according to the present invention, the arithmetic processing unit performs an integration of the count value and the sample time of each piece of the count value information sequentially from the latest count value information, and calculates the integration time in advance. From the integrated value Na of the count value which becomes the set value A, the count rate na is calculated as Na / A.
A-type arithmetic processing unit, which is obtained as follows, and an integrated value Tb of a sample time at which the integrated value of the count value becomes a preset value B.
And a B-type arithmetic processing unit for calculating the count rate nb as B / Tb from the formula (1). When the count rate n is equal to or less than the set value C, the calculation result by the A-type arithmetic processing unit is obtained. Is designed to output the operation result by the B-type operation processing unit as an operation result, so that it has a Gaussian distribution at a normal background count rate, and has an effect of responding at high speed in a high count rate region.

According to the digital counting rate meter according to the present invention, the arithmetic processing unit sequentially integrates the count value and the sample time retroactively from the latest count value information of the time-series information, and sets the integrated time in advance. An A-type operation unit for calculating the count rate na = Na / A from the integrated value Na of the count value that becomes the set value A, and a negative feedback count calculated by multiplying the count rate and the unit sample time in the immediately preceding operation cycle. The difference between the value and the count value obtained from the latest count value information is algebraically integrated to obtain an integrated count value, and the count rate is calculated from the integrated count so that the standard deviation of the fluctuation of the count rate becomes the set value D. A D-type operation unit that outputs an output of the A-type operation unit when the count rate of the A-type operation unit is equal to or less than the set value C, and a D-type operation when the count rate of the A-type operation unit is equal to or more than the set value C. Division output , So that the normal background count rate has a Gaussian distribution, and in the high count rate region, a high-speed response and a high-speed calculation rate meter can be obtained, and the standard deviation of fluctuations can be obtained. There is an effect that can be constant.

According to the digital counting rate meter according to the present invention, the D-type operation unit calculates the integrated count value as M, γ = 2σ
² (σ is the standard deviation of the fluctuation of the counting rate)
(M) = 2 ^{Since the} integrated count value is calculated as the count rate by the relational expression of ^{rM / ln2} , the standard deviation of fluctuation can be made constant.

According to the digital counting rate meter according to the present invention, the arithmetic processing unit sequentially integrates the count value and the sample time retroactively from the latest count value information of the time-series information, and calculates the integration time in advance. An A-type operation unit for calculating the count rate na = Na / A from the integrated value Na of the count value that becomes the set value A, a pulse to be measured is added to an addition terminal, a negative feedback pulse is added to a subtraction terminal, and the difference is calculated. An up-down counter that algebraically integrates to obtain an integrated count value, a pulse generator that receives the integrated count value of the up-down counter and generates the negative feedback pulse at a count rate corresponding thereto, and a fluctuation of the count rate And an arithmetic circuit for calculating the count rate from the integrated count value so that the standard universal difference becomes the set value E. In this case, the output of the A-type operation unit is output as the count rate when the count rate of the A-type operation unit is equal to or more than the set value C, so that the normal background count rate is Gaussian. It is possible to obtain a distribution rate, high-speed response in the high counting rate area and a high counting rate meter with a high calculation speed, and there is an effect that the counting error is small with respect to the high counting rate and the standard deviation of fluctuation can be kept constant. .

Further, according to the digital counting rate meter according to the present invention, the E-type operation unit sets the integrated count value to M, γ = 2σ
² (σ is the standard deviation of the fluctuation of the counting rate)
(M) = 2 ^Since the arithmetic circuit for calculating the integrated count value into the count rate by the relational expression of ^{rM / ln2} is configured, there is an effect that the standard deviation of fluctuation can be ^kept constant.

Further, according to the digital counting rate meter according to the present invention, since there is provided a means for changing the set value of the integrated count value of the calculating section, there is an effect that the standard deviation of fluctuation can be set to an arbitrary value. Further, according to the digital counting rate meter according to the present invention, the set value C for switching the counting rate is different between when the counting rate increases and when the counting rate decreases, so that a stable operation at the time of switching can be obtained. There is.

Further, according to the digital counting rate meter according to the present invention, the set value C of the counting rate when the rising rate is increased is compared with the setting value C of the counting rate when the set value C for switching the counting rate is decreased. Since the setting means for setting a large value is provided, there is an effect that the switching of the counting rate can be stably set.

Further, according to the digital counting rate meter according to the present invention, the arithmetic processing unit is provided with the burst judging unit for judging the count value information on the burst pulse, and the integration is performed except for the burst pulse. This has the effect of preventing false alarms against transient noise.

Further, according to the digital counting rate meter according to the present invention, when the count value of the latest count value information is equal to or more than the set value J, the burst flag for treating the latest count value information as a burst is provided. Is stored in the memory unit, and the integration processing of the count information is controlled based on the count value information with the burst flag. Therefore, there is an effect that false alarms due to burst pulses can be reduced.

Further, according to the digital counting rate meter according to the present invention, the arithmetic section counts the number of burst flags within the range of the set time sequentially from the latest count value information to the past. When the value is less than the set value G, the count value is integrated by removing the count value information with the burst flag retrospectively from the latest count value in the time series and calculating a count rate based on the integrated count value. When the number of the burst flags is equal to or more than the set value G, the latest count value is corrected to be non-burst and the count rate is calculated. Since all new data is treated as non-burst, there is an effect that false alarms can be reduced with respect to noise in which the count number of the count value information is wide.

Further, according to the digital counting rate meter according to the present invention, the burst judging unit fetches a signal indicating that the test state is in effect at the time of inputting the test pulse, and stops the burst judging function. The test can be smoothly performed by the test signal of the count number.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a digital count rate meter according to the present invention.

FIG. 2 is a configuration diagram of an arithmetic processing unit of the digital count rate meter according to the first embodiment.

FIG. 3 is a configuration diagram of a memory unit 22 according to the first embodiment.

FIG. 4 is a diagram illustrating response characteristics when the number of input pulses increases stepwise according to the first embodiment;

FIG. 5 is a configuration diagram of an arithmetic processing unit of the digital count rate meter according to the second embodiment.

FIG. 6 is a diagram illustrating response characteristics when the number of input pulses increases stepwise according to the second embodiment.

FIG. 7 is a configuration diagram of an arithmetic processing unit of the digital count rate meter according to the third embodiment.

FIG. 8 is a configuration diagram of a D-type operation unit according to the third embodiment.

FIG. 9 is a configuration diagram of an arithmetic processing unit of the digital count rate meter according to the fourth embodiment.

FIG. 10 is a diagram showing a flowchart of a fifth embodiment.

FIG. 11 is a configuration diagram of an arithmetic processing unit of a digital count rate meter according to a sixth embodiment including a determination unit.

FIG. 12 is a configuration diagram of an arithmetic processing unit of a digital count rate meter according to a seventh embodiment including a determination unit.

FIG. 13 is a configuration diagram of an arithmetic processing unit of a digital count rate meter according to an eighth embodiment including a determination unit.

FIG. 14 is a configuration diagram of an arithmetic processing unit of the digital count rate meter according to the ninth embodiment.

FIG. 15 is a configuration diagram of a counting rate meter according to a conventional example.

[Explanation of symbols]

1 counter section, 2 arithmetic processing section, 21 preprocessing section,
22 memory unit, 23 operation unit, 23A A-type operation unit, 23B B-type operation unit, 23D D-type operation unit, 2
3E E type operation unit, 23D1 subtraction circuit, 23D2
Integration circuit, 23D3 operation circuit D, 23E1 operation circuit E, 24 output switching control section 25 up / down counter, 26 pulse generation circuit, 27 determination section,
28 Test signal section, 3 control signal section.

Claims (18)

[Claims] A counter for collecting the number of pulses to be measured as count value information over a sampling time determined for each sampling period;
A preprocessing unit for adding the time-series information of the count value information to each of the count value information; and accumulating the count value information with the time-series information and specifying the time-series information to generate predetermined count value information. Based on the memory unit to be read and the time-series information, the count value information is read out sequentially from the newest count value information, and the count rate is calculated from the integrated value of the count value of each count value information and the integrated value of the sample time. A digital count rate meter that includes a calculation processing unit that calculates the count value and outputs the count rate by performing the above-described calculation processing in each calculation cycle. 2. An arithmetic processing unit sequentially integrates a count value and a sample time relating to each count value information sequentially from the latest count value information of the time-series information, and the integrated value of the count value is a preset value. 2. The digital count rate meter according to claim 1, wherein the count rate is calculated as B / Tb from the integrated value Tb of the sample time of B. 3. The digital count rate meter according to claim 2, wherein the set value B can be variably set. 4. An arithmetic processing unit which sequentially integrates a count value and a sample time associated with each piece of count value information retroactively from the latest count value information so that the integrated time becomes a preset value A. A type arithmetic processing unit for calculating the count rate na from the integrated value Na as Na / A, and the count rate nb as B / Tb from the integrated value Tb of the sample time when the integrated value of the count value becomes the preset value B. A calculation result by the A-type processing unit when the count rate n is equal to or less than the set value C, and a calculation result by the B-type calculation processing unit when the count rate n is equal to or more than the set value C The digital count rate meter according to any one of claims 1 to 3, wherein is output as a calculation result. 5. The digital count rate meter according to claim 4, wherein the set values A, B and C can be variably set. 6. The arithmetic processing unit sequentially integrates the count value and the sample time, starting from the latest count value information of the time-series information, and sets the integrated time to a preset value A
From the integrated value Na of the count value, the count rate na = Na /
A type arithmetic unit for calculating A, and the difference between the negative feedback count value calculated by the product of the count rate in the immediately preceding arithmetic cycle and one unit of sample time and the count value obtained from the latest count value information is algebraically calculated. And a D-type operation unit for calculating the count rate from the integrated count value so that the standard deviation of the fluctuation of the count rate becomes the set value D. The output of the A-type operation unit is output as the count rate when the value is equal to or less than the set value C, and the output of the D-type operation unit is output as the count rate when the count rate of the A-type operation unit is equal to or more than the set value C. The digital count rate meter according to claim 1. 7. The D-type operation unit calculates the integrated count value as M, γ
= 2σ ² (σ is the standard deviation of the fluctuation of the counting rate, γ is a constant)
7. The digital counting rate meter according to claim 6, wherein an integrated count value is calculated as a counting rate by a relational expression of counting rate N (M) = 2 ^{rM / ln2} . 8. The digital count rate meter according to claim 6, wherein the set values A, C and D can be variably set. 9. The arithmetic processing unit sequentially integrates the count value and the sample time starting from the latest count value information of the time-series information, and sets the integrated time to a preset value A
From the integrated value Na of the count value, the count rate na = Na /
An A-type operation unit for obtaining A, an up / down counter for applying a measured pulse to an addition terminal, applying a negative feedback pulse to a subtraction terminal, and algebraically integrating the difference to obtain an integrated count value; A pulse generator for inputting the integrated count value and generating the negative feedback pulse having a count rate corresponding to the integrated count value;
And an operation circuit for calculating a count rate from the integrated count value so that the output of the A-type operation section is provided when the count rate of the A-type operation section is equal to or less than the set value C.
2. The digital count rate meter according to claim 1, wherein when the count rate of the A-type operation unit is equal to or more than the set value C, the output of the E-type operation unit is output as the count rate. 10. The arithmetic circuit calculates an integrated count value by M, γ
= 2σ ² (σ is the standard deviation of the fluctuation of the counting rate), and is constituted by an arithmetic circuit that converts the integrated count value into the counting rate by a relational expression of the counting rate N (M) = 2 ^{rM / ln2.} A digital counting rate meter according to claim 9. 11. The digital counting rate meter according to claim 9, wherein the setting values A, C and E can be variably set. 12. The digital counting method according to claim 4, wherein the set value C of the counting rate is different when the counting rate increases and when the counting rate decreases. Rate meter. 13. The digital counting rate according to claim 12, further comprising setting means for setting the set value C of the counting rate when falling to be smaller than the set value C of the counting rate when rising. Total. 14. The arithmetic processing unit further includes a burst determination unit that checks in order from the latest count value information to F set values and compares the count value information with a set value related to the burst information to make a determination. The digital count rate meter according to any one of claims 1 to 13, wherein: 15. The burst judging section adds a burst flag for treating the latest count value information as a burst when the count value of the latest count value information is equal to or more than a set value J, and stores the burst value in the memory section. The digital count rate meter according to claim 14, wherein 16. The arithmetic processing unit counts the number of burst flags within a set time range sequentially from the latest count value information to the past, and if the number of burst flags is less than the set value G, the latest The count value is integrated by counting back from the count value in time series except for the count value information with the burst flag, and the count rate is calculated based on the integrated count value, and the number of the burst flags is equal to or greater than the set value G. In the case of, the latest count value is corrected to be non-burst and the count rate is calculated. Thereafter, all new data is treated as non-burst until the number of elapsed operation cycles reaches the set value H. 2. The method according to claim 1, wherein
A digital count rate meter according to claim 4 or claim 15. 17. One or two of set values G, H and J
The digital count rate meter according to any one of claims 14 to 16, wherein at least one of them can be variably set. 18. The digital counting rate meter according to claim 14, wherein the burst determination unit captures a signal indicating a test state when a test pulse is input, and stops the burst determination function.