JP2021196291A - Dust radiation monitor and method for measuring dust radiation - Google Patents

Abstract

To measure a dust radiation over a wide measurement range even if there is a significant change in the concentration of dust.SOLUTION: A dust radiation monitor according to an embodiment includes a radiation detector 15, a counting processing circuit 17, an average current processing unit 18; and a concentration operation unit 19. The concentration operation unit 19 includes: a counting rate concentration operation unit 33 for calculating the concentration of a counting rate on the basis of the counting rate; an average current concentration operation unit 34 for calculating an average current concentration on the basis of the average current; and an added average calculation unit 35 for calculating an added average of the counting rate concentration and the average current concentration when the counting rate concentration is higher than a low concentration reference value and the average current concentration is lower than a high concentration reference value.SELECTED DRAWING: Figure 1

Description

Embodiments of the present invention relate to a dust radiation monitor and a dust radiation measuring method.

When working in a radiation controlled area, measure the concentration of radioactive substances contained in the air of the work area (radioactivity per unit volume, hereinafter also referred to as "dust concentration"), and monitor the safety of the area. It is essential to do it all the time. There is a dust radiation monitor as a device to achieve this. In measuring the dust concentration, a pipe is laid from the sampling point to the measuring device, the gas sucked by the pump is collected by the filter paper, and the radiation emitted from the filter paper is detected by the radiation detector placed on the opposite side of the filter paper. A general method is to count the pulsed electric signals output from them and calculate the dust concentration based on them.

However, for example, in a work area where buildings and equipment are being demolished, a large amount of dust may fly up during the work, and gas containing high-concentration radioactive substances may be sucked temporarily or for a certain period of time. obtain. At this time, since the radiation detector frequently detects radiation, it is assumed that accurate counting becomes difficult due to frequent occurrence and superposition of each pulse-shaped electric signal output from the radiation detector. In other words, when the dust concentration is high enough to exceed the upper limit of measurement as a measuring device, there is a concern that the measuring device will be saturated and monitoring will be difficult, and a solution is required.

On the other hand, in the radiation measurement system, when the radiation dose is low, the radiation dose is evaluated based on the radiation count rate, and when the radiation dose is high, the radiation dose is evaluated based on the average current within a predetermined time. Has been done.

Japanese Unexamined Patent Publication No. 61-62886 Japanese Unexamined Patent Publication No. 2003-35779

However, there is no known technique for continuously and continuously measuring the dust concentration over a wide measurement range from the low concentration region to the high concentration region when the dust concentration changes drastically.

An object of the present invention is to enable continuous and continuous measurement of dust radiation over a wide measurement range even when the dust concentration changes significantly.

The dust radiation monitor according to the embodiment of the present invention includes a dust collecting container for circulating a gas containing dust, a filter attached to the dust collecting container to collect the dust and allow the gas to pass through, and the filter. A radiation detector that detects the radiation emitted from the dust collected in the above and outputs an electric signal, a counting processing circuit that calculates the count rate of the radiation based on the output of the radiation detector, and the radiation detector. In the gas, based on the average current processing unit that calculates the average current of the output within a predetermined time, the counting rate obtained by the counting processing circuit, and the average current obtained by the average current calculating unit. A dust radiation monitor having a concentration calculation unit for calculating the dust concentration of the above, and the concentration calculation unit is based on the count rate assuming that the count rate is proportional to the dust concentration in the gas. Assuming that the average current is proportional to the dust concentration in the gas, the count rate concentration calculation unit that calculates the count rate concentration corresponding to the dust concentration in the gas is assumed to be proportional to the dust concentration in the gas. The output of the average current concentration calculation unit that calculates the average current concentration corresponding to the dust concentration and the count rate concentration calculation unit is higher than the predetermined low concentration reference value, and the output of the average current concentration calculation unit is the low concentration. A weighted average calculation unit for calculating a weighted average of the count rate concentration and the average current concentration when the count rate concentration is lower than a predetermined high concentration reference value higher than the reference value, and the weighted average is the count rate. The closer the concentration is to the low concentration reference value, the larger the weighting factor to the counting rate concentration, and the closer the average current concentration is to the high concentration reference value, the larger the weighting factor to the average current concentration. The weighting factor for the count rate concentration is 1 when the count rate concentration is equal to the low concentration reference value, and is zero when the average current concentration is equal to the high concentration reference value. , Is characterized.

Further, in the dust radiation measuring method according to the embodiment of the present invention, a dust collecting step of permeating a gas containing dust through a filter to collect the dust and a radiation emitted from the dust collected by the filter are obtained. A radiation detection step that detects an electric signal by a radiation detector and outputs an electric signal, a counting processing step that calculates a current count rate based on the output of the radiation detector, and an average of the outputs of the radiation detector within a predetermined time. Assuming that the average current calculation step for calculating the current is proportional to the count rate and the dust concentration in the gas, the count rate concentration corresponding to the dust concentration in the gas is calculated based on the count rate. The average current concentration for calculating the average current concentration corresponding to the dust concentration in the gas based on the average current, assuming that the count rate concentration calculation step is proportional to the average current and the dust concentration in the gas. The calculation step and the count rate concentration when the count rate concentration is higher than the predetermined low concentration reference value and the average current concentration is lower than the predetermined high concentration reference value higher than the low concentration reference value. It is a dust radiation measuring method including a weighted average calculation step for calculating a weighted average with the average current concentration. In the weighted average, the closer the count rate concentration is to the low concentration reference value, the more the count rate concentration is. The weighting rate is large, and the closer the average current concentration is to the high concentration reference value, the greater the weighting rate to the average current concentration. When the count rate concentration is equal to the low concentration reference value, it is set to 1, when the average current concentration is equal to the high concentration reference value, it is set to zero, and when the count rate concentration is equal to or less than the low concentration reference value, it is set to 1. The count rate concentration is defined as the dust concentration in the gas, and when the average current concentration is equal to or higher than the high concentration reference value, the average current concentration is defined as the dust concentration in the gas, and the count rate concentration is the low concentration. When the average current concentration is higher than the reference value and the average current concentration is lower than the high concentration reference value, the weighted average is used as the dust concentration in the gas.

According to the embodiment of the present invention, dust radiation can be continuously measured without interruption over a wide measurement range even when the dust concentration changes significantly.

The block diagram which shows the structure of one Embodiment of the dust radiation monitor which concerns on this invention. The flow chart which shows the procedure of one Embodiment of the dust radiation measurement method using the dust radiation monitor of FIG. It is a figure for demonstrating the method of the dust concentration calculation in one Embodiment of the dust radiation monitor which concerns on this invention, the horizontal axis is a true duct concentration, and the vertical axis is a dust concentration instruction value. FIG. 5 is a flow chart showing a procedure for determining a low concentration reference value, a high concentration reference value, and a weighting factor relational expression in one embodiment of the dust radiation measurement method using the dust radiation monitor of FIG. 1.

Hereinafter, the dust radiation monitor and the dust radiation measurement method according to the embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing a configuration of an embodiment of a dust radiation monitor according to the present invention. This dust radiation monitor includes a dust collecting container 12, a suction pump 13, a filter paper (filter) 14, a radiation detector 15, an amplifier circuit 16, a counting processing circuit 17, an average current processing unit 18, and a concentration calculation. It has a part 19.

A gas introduction pipe 21 and a gas discharge pipe 22 are connected to the dust collection container 12, and a suction pump 13 is attached to the gas discharge pipe 22. The filter paper 14 is attached to the dust collecting container 12. The gas (for example, air) 11 containing dust (dust) to be measured is introduced from the gas introduction pipe 21 into the dust collection container 12, passes through the filter paper 14, is sucked by the suction pump 13, and is sucked from the gas discharge pipe 22. It is discharged. The dust contained in the gas 11 is collected by the filter paper 14. The filter paper 14 has innumerable fine holes and is made of a paper or resin material. A filter paper winder (not shown) is attached to the dust collector container 12, and every time radiation detection is completed within a predetermined time (for example, several minutes to several hours), a portion of the new filter paper 14 is exposed to the gas 11. It is configured to be.

The radiation detector 15 converts the radiation emitted from the dust collected by the filter paper 14 into an electric signal, and has a scintillator 25 that detects radiation (for example, β rays) and emits light, and a scintillator 25 that emits light when it receives light. It has a photomultiplier tube 26 that outputs a corresponding electric signal. When the radiation 24 is incident on the radiation detector 15, the scintillator 25 generates a slight fluorescence. The light emitted from the scintillator 25 is incident on the photomultiplier tube 26 to generate photoelectrons, the number of electrons is amplified to several hundreds to tens of thousands times, and the light is output as a pulsed electric signal from the photomultiplier tube 26. Will be done. The radiation detector 15 has a closed housing and is configured to prevent light from entering from the outside.

The amplifier circuit 16 is connected to the radiation detector 15 by a cable 30 and amplifies the electric signal output from the photomultiplier tube 26.

Based on the output of the amplifier circuit 16, the counting processing circuit 17 performs wave height discrimination processing for removing signals below the set threshold value, counts the number of electric signals per unit time, and counts the counting rate (per unit time). Number of pulses) is calculated.

The average current processing unit 18 calculates the average current value, which is the average of the electric signals output from the amplifier circuit 16 within a predetermined time.

The density calculation unit 19 outputs the dust concentration based on the output of the counting processing circuit 17 and the output of the average current processing unit 18, and is weighted by the counting rate concentration calculation unit 33, the average current concentration calculation unit 34, and the weight. It has an average calculation unit 35 and an output selection unit 36.

The count rate concentration calculation unit 33 calculates the dust concentration by multiplying the count rate R, which is the output of the count processing circuit 17, by a conversion coefficient. The calculation for calculating the dust concentration is, for example, by the following equation (1). In the formula (1), C is the dust concentration, R is the counting rate, η is the detection efficiency peculiar to the detector, Q is the average value of the flow rate of the gas passing through the filter paper 14, t is the elapsed dust collection time, and D is the filter paper 14. It is a unique collection efficiency. When this equation (1) is used, the conversion coefficient is D · η / (Q · t). Note that (Q.t) is the volume of gas that has passed through the filter 14 within the elapsed time of dust.

C = D ・ η ・ R / (Q ・ t) ・ ・ ・ (1)
The dust concentration obtained by the counting rate concentration calculation unit 33 is referred to as a "counting rate concentration" here. When the dust concentration is relatively low, the count rate concentration is used as the duct concentration.

The average current density calculation unit 34 obtains the dust concentration by multiplying the output of the average current processing unit 18 by a coefficient. This coefficient shows the relationship between the average current and the counting rate, and is assumed to be obtained in advance. The dust concentration obtained by the average current density calculation unit 34 is referred to here as an "average current density". When the dust concentration is relatively high, the average current concentration is used as the duct concentration.

Both the output of the count rate density calculation unit 33 and the output of the average current density calculation unit 34 are input to the weighted average calculation unit 35 and the output selection unit 36. The weighted average calculation unit 35 calculates the weighted average of the count rate concentration and the average current concentration when the count rate concentration is higher than the predetermined low concentration reference value and the average current concentration is lower than the predetermined high concentration reference value. , The result is output to the output selection unit 36. The high concentration reference value is higher than the low concentration reference value. The calculation method of the high concentration reference value, the low concentration reference value and the weighted average will be described later with reference to FIGS. 3 and 4.

The output selection unit 36 outputs the count rate concentration as the duct concentration when the count rate concentration is equal to or less than the low concentration reference value, and outputs the average current concentration as the duct concentration when the average current concentration is equal to or higher than the high concentration reference value. When the count rate concentration is higher than the low concentration reference value and the average current concentration is lower than the high concentration reference value, the output of the weighted average calculation unit 35 is output as the duct concentration.

FIG. 2 is a flow chart showing a procedure of one embodiment of the dust radiation measuring method using the dust radiation monitor of FIG. 1.

First, the gas 11 containing dust is passed through the filter 14 to collect the dust (dust collection step S11). Next, the radiation emitted from the dust collected by the filter 14 is detected by the radiation detector 15 and an electric signal is output (radiation detection step S12).

Next, the counting processing circuit 17 calculates the radiation counting rate based on the output of the radiation detector 15 (counting processing step S13). Further, the average current processing unit 18 calculates the average current of the output of the radiation detector 15 within a predetermined time (average current calculation step S14).

Next, assuming that the counting rate is proportional to the dust concentration in the gas, the counting rate concentration calculation unit 33 calculates the counting rate concentration corresponding to the dust concentration in the gas based on the counting rate and the volume of the gas. Calculate (counting rate concentration calculation step S15). Further, the average current concentration calculation unit 34 calculates the average current concentration corresponding to the dust concentration in the gas based on the average current and the volume of the gas, assuming that the average current is proportional to the dust concentration in the gas. (Average current density calculation step S16).

Next, when the count rate concentration is higher than the predetermined low concentration reference value and the average current concentration is lower than the predetermined high concentration reference value higher than the low concentration reference value, the weighted average calculation unit 35 determines the count rate. A weighted average of the concentration and the average current concentration is calculated (weighted average calculation step S17).

Next, the output selection unit 36 selects one of the count rate concentration, the average current density, and the weighted average and outputs it as the dust concentration in the gas (concentration measurement result output step S18). Here, when the count rate concentration is below the low concentration reference value, the count rate concentration is selected as the dust concentration in the gas, and when the average current concentration is above the high concentration reference value, the average current concentration is set in the gas. Select as the dust concentration of. When the count rate concentration is higher than the low concentration reference value and the average current concentration is lower than the high concentration reference value, the weighted average is selected as the dust concentration in the gas.

Here, a method of obtaining a dust concentration in a wide range using the count rate concentration and the average current concentration will be described with reference to FIG.

FIG. 3 is a diagram for explaining a method for calculating the dust concentration in one embodiment of the dust radiation monitor according to the present invention, in which the horizontal axis represents the true duct concentration and the vertical axis represents the dust concentration indicated value. ..

The counting rate concentration by the counting processing circuit 17 has high accuracy at a relatively low counting rate, and the average current concentration by the average current processing unit 18 has high accuracy at a relatively high counting rate. The counting processing circuit 17 has a high counting rate, that is, when a large amount of radioactive material is collected on the filter paper 14, the frequency of pulsed electric signals becomes very high, and the respective electric signals are superimposed to be accurate. It becomes difficult to count and the accuracy decreases. Further, since the average current processing unit 18 performs averaging with a pulsed electric signal at a relatively low count rate, the accuracy is low.

As shown in FIG. 3, the indicated value C1 of the counting rate concentration by the counting processing circuit 17 corresponds to the true dust concentration when the true dust concentration is relatively low below the low concentration reference value CL. Therefore, when the true dust concentration is relatively low, which is equal to or lower than the low concentration reference value CL, the indicated value C1 of the count rate concentration can be set as the true dust concentration. When the true dust concentration exceeds the low concentration reference value CL, the indicated value C1 of the count rate concentration indicates a value lower than the true dust concentration.

The indicated value C2 of the average current density by the average current processing unit 18 corresponds to the true dust concentration when the true dust concentration is relatively high above the high concentration reference value CH. Therefore, when the true dust concentration is relatively high, which is equal to or higher than the high concentration reference value CH, the indicated value C2 of the count rate concentration can be set as the true dust concentration. When the true dust concentration is lower than the high concentration reference value CH, the indicated value C2 of the count rate concentration shows a value higher than the true dust concentration.

For the intermediate region of CL to CH, the weighted average of the indicated value C1 of the count rate concentration by the counting process and the indicated value C2 of the average current concentration by the average current is calculated by the following equation (2), and this weighted average is used as dust. Let it be the concentration.

C = k ・ C1 + (1-k) ・ C2 ・ ・ ・ (2)
Here, k is a weighting factor to the count rate concentration, which is a function of the indicated value C1 of the count rate concentration and the indicated value C2 of the average current concentration, and is a value from zero to one. The weighting factor for the average current density is (1-k). When the indicated value C1 of the count rate concentration is equal to the low concentration reference value CL, k = 1, and when the indicated value C2 of the average current density is equal to the high concentration reference value CH, k = 0. In the intermediate region of CL to CH, the weighting factor k to the count rate concentration becomes smaller as the indicated value C1 of the count rate concentration is larger and as the indicated value C2 of the average current concentration is larger.

Next, a procedure for determining the low concentration reference value, the high concentration reference value, and the weighting factor relational expression required for performing the above processing will be described with reference to FIG. FIG. 4 is a flow chart showing a procedure for determining a low concentration reference value, a high concentration reference value, and a weighting factor relational expression in one embodiment of the dust radiation measuring method using the dust radiation monitor of FIG.

In determining these values and relational expressions, first, using the dust radiation monitor shown in FIG. 1, a dust collection step S11 and a radiation detection step for each of at least three types of gases having known dust concentrations. S12 and the counting process step S13 (see FIG. 2) are performed. As a result, the relationship between the counting rate and the dust concentration is obtained (counting rate dust concentration relationship acquisition step S51). As a result, the curve of the dust concentration indicated value C1 by the counting process of FIG. 3 can be obtained.

Similarly, using the dust radiation monitor shown in FIG. 1, the dust collection step S11, the radiation detection step S12, and the average current calculation step S14 are further performed for each of at least three types of gases having known dust concentrations (FIG. 2). See). As a result, the relationship between the average current and the dust concentration is obtained (average current dust concentration relationship acquisition step S52). As a result, the curve of the dust concentration indicated value C2 based on the average current in FIG. 3 can be obtained.

The gas having a known dust concentration used in the above-mentioned count rate dust concentration relationship acquisition step S51 and the gas having a known dust concentration used in the average current dust concentration relationship acquisition step S52 are partially or wholly common. There may be. When the gas having a known dust concentration is common, the dust collection step S11 and the radiation detection step S12 in the count rate dust concentration relationship acquisition step S51 and the average current dust concentration relationship acquisition step S52 are common steps. Can be.

Next, the low concentration reference value CL is obtained as the point where the curve of the dust concentration indicated value C1 obtained by the counting process in FIG. 3 starts to deviate from the straight line passing through the origin at the slope 1 (low concentration reference value determination step S53). The curve of the dust concentration indicated value C1 by the counting process is a straight line passing through the origin with a slope of 1 in the region below the low concentration reference value CL.

Similarly, the high concentration reference value CH is obtained as the point where the curve of the concentration indicated value C2 based on the average current in FIG. 3 starts to deviate from the straight line passing through the origin at the slope 1 (high concentration reference value determination step S54). The curve of the concentration indicated value C2 based on the average current is a straight line passing through the origin with a slope of 1 in the region above the high concentration reference value CH.

Next, in FIG. 3, in the region (intermediate region) where the true dust concentration is between the low concentration reference value CL and the high concentration reference value CH, the formula of the weighting factor k that satisfies the formula (2) is determined ( Weighted rate relational expression determination step S55).

Here, the weighting factor k is a function of the dust concentration indicated value C1 by the counting process and the concentration indicated value C2 by the average current, and is the curve of the true dust concentration C in FIG. 3 and the dust concentration indicated value C1 by the counting process. The relational expression can be determined from the relation of the curve of the concentration indicated value C2 by the average current.

According to the embodiment described above, even when the dust concentration changes significantly, the dust radiation can be continuously measured over a wide measurement range without interruption.

In the embodiment of the dust radiation monitor described above, the counting processing circuit 17, the average current processing unit 18, and the concentration calculation unit 19 can be realized by hardware such as an electronic circuit, but a part or all of them can be realized by a computer. It can also be realized by the software of.

[Other embodiments]
Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other embodiments, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and variations thereof are included in the scope of the invention described in the claims and the equivalent scope thereof, as are included in the scope and gist of the invention.

11 ... Gas (air), 12 ... Dust collection container, 13 ... Suction pump, 14 ... Filter paper (filter), 15 ... Radiation detector, 16 ... Amplification circuit, 17 ... Counting processing circuit, 18 ... Average current processing unit, 19 ... concentration calculation unit, 21 ... gas introduction pipe, 22 ... gas discharge pipe, 24 ... radiation, 25 ... scintillator, 26 ... photoelectron multiplier tube, 30 ... cable, 33 ... count rate concentration calculation unit, 34 ... average current concentration calculation Unit, 35 ... Weighted average calculation unit, 36 ... Output selection unit

Claims (4)

A dust collection container that circulates gas containing dust,
A filter attached to the dust collecting container to collect the dust and allow the gas to permeate.
A radiation detector that detects the radiation emitted from the dust collected by the filter and outputs an electric signal,
A counting processing circuit that calculates the radiation counting rate based on the output of the radiation detector, and
An average current processing unit that calculates the average current of the output of the radiation detector within a predetermined time, and
A concentration calculation unit that calculates the dust concentration in the gas based on the counting rate obtained by the counting processing circuit and the average current obtained by the average current calculation unit.
Is a dust radiation monitor with
The concentration calculation unit is
A counting rate concentration calculation unit that calculates the counting rate concentration corresponding to the dust concentration in the gas based on the counting rate, assuming that the counting rate is proportional to the dust concentration in the gas.
An average current concentration calculation unit that calculates an average current concentration corresponding to the dust concentration in the gas based on the average current, assuming that the average current and the dust concentration in the gas are proportional to each other.
When the output of the count rate concentration calculation unit is higher than the predetermined low concentration reference value and the output of the average current concentration calculation unit is lower than the predetermined high concentration reference value higher than the low concentration reference value, the said A weighted average calculation unit that calculates a weighted average of the count rate concentration and the average current concentration,
Equipped with
As for the weighted average, the closer the count rate concentration is to the low concentration reference value, the larger the weight rate to the count rate concentration, and the closer the average current concentration is to the high concentration reference value, the greater the weight rate to the average current concentration. The weighting factor to the count rate concentration is 1 when the count rate concentration is equal to the low concentration reference value, and the average current concentration is the high concentration reference value. Be zero when equal to
A dust radiation monitor featuring. When the count rate concentration is equal to or lower than the low concentration reference value, the count rate concentration is output as the dust concentration in the gas.
When the average current concentration is equal to or higher than the high concentration reference value, the average current concentration is output as the dust concentration in the gas.
When the count rate concentration is higher than the low concentration reference value and the average current concentration is lower than the high concentration reference value, the weighted average is output as the dust concentration in the gas. That
The dust radiation monitor according to claim 1. A dust collection step in which a gas containing dust is permeated through a filter to collect the dust,
A radiation detection step in which a radiation detector detects radiation emitted from the dust collected by the filter and outputs an electric signal, and a radiation detection step.
A counting process step for calculating the radiation counting rate based on the output of the radiation detector, and
An average current calculation step for calculating the average current of the output of the radiation detector within a predetermined time, and
Assuming that the counting rate is proportional to the dust concentration in the gas, the counting rate concentration calculation step for calculating the counting rate concentration corresponding to the dust concentration in the gas based on the counting rate,
Assuming that the average current is proportional to the dust concentration in the gas, the average current concentration calculation step for calculating the average current concentration corresponding to the dust concentration in the gas based on the average current,
When the count rate concentration is higher than the predetermined low concentration reference value and the average current concentration is lower than the predetermined high concentration reference value higher than the low concentration reference value, the count rate concentration and the average current concentration are used. And the weighted average calculation step to calculate the weighted average of
It is a dust radiation measurement method equipped with
As for the weighted average, the closer the count rate concentration is to the low concentration reference value, the larger the weight rate to the count rate concentration, and the closer the average current concentration is to the high concentration reference value, the greater the weight rate to the average current concentration. The weighting factor to the count rate concentration is set to 1 when the count rate concentration is equal to the low concentration reference value, and the average current concentration is set to the high concentration reference value. Zero when equal
When the count rate concentration is equal to or lower than the low concentration reference value, the count rate concentration is defined as the dust concentration in the gas.
When the average current concentration is equal to or higher than the high concentration reference value, the average current concentration is defined as the dust concentration in the gas.
When the count rate concentration is higher than the low concentration reference value and the average current concentration is lower than the high concentration reference value, the weighted average shall be the dust concentration in the gas.
A dust radiation measurement method characterized by. By performing the dust collection step, the radiation detection step, and the counting processing step for each of at least three types of gases having a known dust concentration, the counting rate dust concentration for obtaining the relationship between the counting rate and the dust concentration is obtained. Relationship acquisition steps and
Average current dust for which the relationship between the average current and the dust concentration is obtained by performing the dust collection step, the radiation detection step, and the average current calculation step for each of at least three types of gases having a known dust concentration. Concentration-related acquisition step and
A reference value determination step for determining the low concentration reference value and the high concentration reference value based on the relationship between the count rate and the dust concentration and the relationship between the average current and the dust concentration.
Based on the relationship between the count rate and the dust concentration and the relationship between the average current and the dust concentration, the weight rate relationship for determining the weight rate relational expression for obtaining the weight rate as a function of the count rate and the average current. Formula determination step and
The dust radiation measuring method according to claim 3, further comprising.

Images