KR20090084003A - A process of detection for a radon gas-density and the device - Google Patents
A process of detection for a radon gas-density and the device Download PDFInfo
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- KR20090084003A KR20090084003A KR1020080009920A KR20080009920A KR20090084003A KR 20090084003 A KR20090084003 A KR 20090084003A KR 1020080009920 A KR1020080009920 A KR 1020080009920A KR 20080009920 A KR20080009920 A KR 20080009920A KR 20090084003 A KR20090084003 A KR 20090084003A
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- radon gas
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01T—MEASUREMENT OF NUCLEAR OR X-RADIATION
- G01T1/00—Measuring X-radiation, gamma radiation, corpuscular radiation, or cosmic radiation
- G01T1/16—Measuring radiation intensity
- G01T1/17—Circuit arrangements not adapted to a particular type of detector
- G01T1/178—Circuit arrangements not adapted to a particular type of detector for measuring specific activity in the presence of other radioactive substances, e.g. natural, in the air or in liquids such as rain water
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01T—MEASUREMENT OF NUCLEAR OR X-RADIATION
- G01T1/00—Measuring X-radiation, gamma radiation, corpuscular radiation, or cosmic radiation
- G01T1/16—Measuring radiation intensity
- G01T1/18—Measuring radiation intensity with counting-tube arrangements, e.g. with Geiger counters
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10S250/00—Radiant energy
- Y10S250/02—Radon detection
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- Life Sciences & Earth Sciences (AREA)
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- High Energy & Nuclear Physics (AREA)
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- Spectroscopy & Molecular Physics (AREA)
- Measurement Of Radiation (AREA)
Abstract
Description
The present invention relates to a method and a device for detecting the concentration of radon gas remaining in the atmosphere in real time, and more particularly, without being affected by atmospheric factors such as temperature and humidity. The present invention relates to a method and apparatus for detecting radon gas concentration, which is capable of continuously detecting the concentration of radon gas in the air at low cost.
In general, the human body is exposed to natural radiation that is normally present in nature and is being irradiated, and is radiated from the universe by alpha rays, beta rays, gamma rays, and the like, which are emitted from radioactive isotopes existing in the air and soil or rocks. Cosmic rays are irradiated to the human body.
In addition, the human body is being irradiated with artificial radiation (medical radiation, TV, fluorescent lamps, radiation generated from all products such as computers, vehicles, transportation means, etc.) generated by the civilization in addition to the natural radiation.
As the radiation irradiated by the human body has various effects on the human body as described above, the International Atomic Energy Agency has set the recommended value of 3 mSv (radiation irradiation unit) per year, and accordingly, the radiation safety guide in Korea should not be exposed more than 1 mSv per year. The tolerance is set.
In particular, the irradiation of alpha radiation by radon gas contained in the air, which occupies 50% or more of the amount of radiation received by humans among the natural radiation as described above, is specially managed separately. It is recommended to keep the concentration below 60-200 Bq / m 3 , although it varies from country to country, and the Republic of Korea currently specifies radon concentration as 4 pCi / l (148 Bq / m 3 ) as the recommended indoor air quality standard.
As mentioned above, the main cause of radiation exposure to the public is that radon gas continuously moves to the ground through soil or gravel surrounding the building, which penetrates into the room through the building space or the pores of concrete. As such, radon penetrating from the surrounding soil is known to be a major cause of indoor radon, and construction materials such as concrete, gypsum board, gravel, and brick also become sources of indoor radon.
In addition, radon is well soluble in water, so it is introduced into the room through the movement of groundwater, and indoor movement through water penetrates due to capillarity or water pressure through the pores of concrete, and the higher the temperature, the lower the pressure. The more radon gas is allowed to enter the room.
As described above, when alpha particle radiation emitted from radioactive isotopes such as radon gas in the atmosphere is irradiated to the human body, alpha particle beams are accumulated in the lungs through the respiratory organs, and thus have a very strong biological effect on humans such as lung cancer. have.
As described above, in order to accurately evaluate the radon concentration in the air having a great influence on the health of the human body, various types of measuring instruments and various measuring methods and devices have been widely developed and used.
As a method and apparatus for measuring and detecting the radon concentration in the atmosphere, a scintillation counter, a gas detector such as a Geiger and a proportional type, a solid state junction counter, etc. Measuring the alpha particles is the majority of the situation.
The scintillation counter has a structure that receives the flash light from the radiation as a photocathode and converts the amplification through the photomultiplier into an electrical signal and sends it to the counting circuit for observation. The scintillation material is processed on the photocathode of the photomultiplier. It is designed to amplify and provide information about the energy and quantity of alpha particles.
In the above, the flash material is coated in an opaque manner so that the surrounding light does not penetrate into the inside of the measuring instrument, and the coating is very thin so that the light leaks when scratched.
In addition, the gas detector-filled alpha detector is a Geiger measuring instrument, an ionization counter or a proportional counter, which is adapted to use a specific gas as a detection material, in which case the gas for detecting alpha or radon must be sealed.
The gas detector is characterized in that alpha particles enter through the thin and brittle plastic or metal window to reach the ionization region, and the pulse flowing between the two poles is proportional to the energy of the incident X-ray photons, depending on the amount of ionization. By measuring the number of pulses, the intensity of radiation can be known. The output signal is constant in the Geiger measurement area, but is related to the energy of alpha particles in the ionization and proportionality areas.
However, such a gas detector can easily damage the sensitive window of the inlet in which the alpha particles enter, the gas-filled alpha detector was insufficient to continuously detect radon.
In addition, when air is used as a measurement gas, electrons are trapped by surrounding charged atoms or molecules, so the output signal is very low, and the reaction surface has to be free from moisture and dust. There were problems that could change that information.
The junction counter is a solid reverse-biased pn junction semiconductor that can be fabricated in a small and mobile type that collects ionic charge from alpha particles passing through a depletion layer, but the metal electrode surface of the detector should not be scratched or peeled off. There is a problem with strict requirements such as being, and such an electrode is sensitive to light and prevents the penetration of ambient light through the surface coating, but there is a problem that light is leaked when scratched.
The present invention has been invented to solve the problems of the conventional method and apparatus for detecting the above-described radon gas in the air, and in particular in the air at low cost in real time without being affected by atmospheric factors such as temperature and humidity. The present invention provides a method and apparatus for detecting the concentration of radon gas which can continuously detect the concentration of radon gas.
Radon gas concentration detection method of the present invention for achieving the object of the present invention as described above comprises the inlet step to be introduced into the first proportional detection means of air in the air through the air pump; A first detection step of obtaining a first measurement number which is a coefficient of a pulse by the number of alpha particles of the radon gas decaying in the air introduced into the first proportional detection means through the inflow step; Pulses caused by the alpha particle number of the radon gas decayed in the air introduced into the second proportional detection means provided with the alpha particle emission material by receiving the air passing through the first detection means and the alpha particle number decayed from the alpha particle emission material A second detection step of obtaining a second measurement number that is a coefficient of? An operation for calculating a concentration of radon gas in the atmosphere calculated by a calculating means for calculating a difference between the first measurement number measured through the first detection step and the second measurement number measured through the second detection step It characterized in that it comprises a step.
The formula of the above calculation step is the number of alpha particles (n1) in the first detection step = the number of alpha particles (n3) * (first measurement number (N1) / second measurement number (N2)- 1st measurement number N1), It is characterized by the above-mentioned.
The first measure number and the second measure number are amplified by the preamplification means and the amplifying means, and are applied to the calculating means.
It characterized in that it further comprises a display means for receiving and displaying the data of the radon gas concentration derived through the above calculation step.
The display means is characterized by comprising an analog display means.
The display means is characterized by consisting of digital display means.
The display means is characterized by consisting of an alarm means that is visually recognized.
The display means is characterized in that it comprises an alarm means that is perceived by hearing.
Radon gas concentration detection apparatus of the present invention for achieving the object of the present invention as described above comprises: a first proportional detection means for introducing air by the pump means; Second proportional detection means connected to the first proportional detection means in series with a connecting pipe and provided with an alpha particle-emitting material therein; The first measurement number which is the coefficient of the pulse by the alpha particle number of the radon gas which decays in the inflowed air obtained by the said first proportional measurement means, and the radon gas which decays in the air which flowed in by the said second proportional measurement means And calculating means for detecting the concentration of radon gas in the atmosphere by receiving the second measurement number which is the coefficient of the pulse by the number of alpha particles and the number of alpha particles decaying from the alpha particle emitting material. have.
In addition, the amplified data is applied between the first proportional measurement means, the second proportional measurement means, and the calculation means through the preamplification means and the amplification means.
It further comprises a display means for receiving and displaying the data of the radon gas concentration derived through the calculation means.
The radon gas concentration detection method and apparatus of the present invention as described above have the effect of continuously detecting the concentration of radon gas in the air at low cost in real time without being affected by atmospheric factors such as temperature and humidity. .
Hereinafter, a method and apparatus for detecting radon gas concentration according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.
1 is a view showing a radon gas concentration detection method and apparatus according to an embodiment according to the present invention, the radon gas concentration detection method of this embodiment is a first proportional detection means for air in the air through the air pumping (3) an inflow step to be introduced into; A first detection step of obtaining a first measurement number which is a coefficient of a pulse by the number of alpha particles of the radon gas decaying in the air introduced into the first proportional detection means (3) through the inflow step; The alpha particle number of the radon gas and the alpha particle releasing substance (5) decayed from the air introduced into the second proportional detection means (6) provided with the alpha particle releasing substance (5) provided with the air passing through the first detecting means (5). A second detection step of obtaining a second measurement number, which is a coefficient of a pulse due to the number of alpha particles decaying in the step; The concentration of the radon gas in the atmosphere is calculated by the calculating
The first measurement number and the second measurement number are amplified by the preamplification means 8 and the amplification means 9 and applied to the calculation means 7.
It further includes a display means 14 to receive and display the data of the radon gas concentration derived through the above calculation step.
The display means 14 may be made of an analog display means or a digital display means, or may be made of an alarm means that can be recognized visually or visually.
The radon gas
The preamplification means 8 and the amplification means 9 are interposed between the first proportional measurement means 3, the second proportional measurement means 6, and the calculation means 7.
In the above, the first and second proportional detection means 3 and 6 have a structure of a conventional proportional counter.
The first and second proportional detection means (3) (6) as described above is to be located inside the normal metal box so as not to be affected by external electromagnetic radiation, the
In addition, the
In addition, the
The preamplification means (8) is made of a conventional preamplifier and the amplification coefficient is most preferably 75.
In the above, the detection time of the first and second proportional detection means (3) (6) is most preferably made of 2-5 minutes when the radioactivity of the alpha particle-emitting material (5) is 3-5Bq.
The radioactivity emitted from the alpha particle-releasing material 5 is composed of very small values and is absolutely safe, and may be composed of several radioisotopes. For example, about 1-3 mg of uranium salt may be used. Can be.
In order to detect the radon gas concentration in the atmosphere by the radon gas concentration detecting method and apparatus of the present embodiment as described above, first and second proportional detection means (3) and (6) are first performed by the pump means (2). When the air is supplied to the air flowing in, the number of alpha particles n1 of the radon gas decayed for a predetermined time is detected in the first proportional detection means 3, and the same wave particles in the second proportional detection means 6 during the same time. The alpha particle number n3 collapsing in the generating material 5 and the alpha particle number n2 collapsing in the introduced radon gas are detected and the first proportional detection means 3 and the second proportional detection means 6 respectively. The number of pearls N1 and N2 is counted according to the number of alpha particles.
N1 and N2 counted as described above are counted as follows.
N1 = n1 * k * K (h, t °, p ...),
N2 = n2 * k * K (h, t °, p ...) + n3 * k * K (h, t °, p ...)
Where k is the measurement efficiency coefficient of the first and second proportional detection means (3) (6), and K (h, t °, p ...) is the humidity of air h, temperature t °, atmospheric pressure p and the electronic device. It is a factor that reflects other variables such as measurement limits due to the low signal of, and voltage values of the high voltage generator.
Since n1 = n2, N2 / N1 may be expressed as follows.
N2 / N1 = [n2 * k * K (h, t °, p ...) + n3 * k * K (h, t °, p ...)] / n1 * k * K (h, t ° , p ...) = (n1 + n3) / n1 = 1 + n3 / n1
According to the above equation, depending on the concentration of radon gas without being influenced by the characteristics of the atmosphere and other factors, n1 can be summarized as follows.
n1 = n3 * N1 / (N2-N1)
When calculating n1, the error (δ) is influenced by the statistical error of N1 and N2, and the statistical error in the Poisson distribution function is δN / N = 1 / √N . The radioactivity should be large enough to prevent the influence of the statistical error of N2 when calculating n1, indicating that the following relationship holds when the measurement rate is at least 1000 cpm (counts per minute).
N2 ＞＞ N1
As described above, the concentration of the redon gas in the atmosphere measured and calculated by the present embodiment can be detected without being affected by atmospheric factors (temperature, humidity) and other variables. It will be described in detail as follows.
Experimental Example 1
The graph below shows that the proportional detection means operates proportionally at the voltage V = 2750 to 3050V of the anode, and the characteristics of the proportional detection means were investigated at the anode voltage V = 2600 to 3100V (50V intervals), and the alpha particle emission. 3 mg of uranium salt (UO 2 (NO 3) 2) was used as the material (5).
Experimental Example 2
The effect of temperature and humidity on the stability during detection was evaluated in a chamber capable of climate change, and for this purpose, another alpha particle-emitting material (5) was also provided in the first proportional detection means (3) and measured. It was.
Atmospheric conditions, air humidity h and temperature t ° are 28% to 95% and 25 ° C to 40 ° C, respectively, and the measurement time is 10 minutes. The results are detected as shown in Table 1.
TABLE 1
As described in Table 1, the number of each measured pulse varies by about 20%, while N 1 / N 2 It is shown that the value is constant within the measurement error.
In addition, the calibration of the proportional detection means utilized air passed through a small 5 ml volume chamber containing 3 g of UO 2 (NO 3 ) 2 at 3 mg, and the measurement of the radiation was measured with RRA-01M-01 and The developed general detector was used.
Measurements were made for UO 2 (NO 3 ) 2 3 mg, 15 mg, 150 mg, 750 mg, 3 g, with five measurements for each and the results of the measurement of radon concentration for the radon concentration C. The error Δ (95% confidence) was used to determine.
In the above, the calibration curve for the proportional detection means can be expressed as approximately the following function.
C = 3 [ N 1 / ( N 2 - N 1 )]
Where C is the concentration of radon expressed in Bq.
Experimental Example 3
The graph below shows the distribution of the error of radon concentration measurement for radon concentration C.
Experimental Example 4
Pump the air into the detector for 30 minutes through a chamber containing 3 g of UO 2 (NO 3 ) 2 for the purpose of investigating the effects of solid radon daughter nuclei deposited on the cathode surface of the proportional detector. It was.
After 5 minutes, the detector of the present example measured N1 and N2 values of 2 Bq / m 3 , but the general radiometer RRA-01M-01 did not measure any value for 5 hours.
The present invention is to be able to measure the concentration of radon gas in the atmosphere without being affected by atmospheric factors and other factors as demonstrated by the experimental examples described above, the detection of the radon gas concentration of the present invention The method and apparatus are provided with an alpha particle-emitting material in one proportional detection means, and the first and second proportional measurements and the first proportional measurement number measured by a pair of proportional detection means connected in series. It is possible to detect the concentration of radon gas in the atmosphere through the difference relationship, the present invention is not limited to the specific preferred embodiment described above, the invention belongs without departing from the gist of the invention claimed in the claims Anyone of ordinary skill in the art can make various modifications, and such changes are within the scope of the claims. Add.
1 is a schematic illustration showing a method and apparatus for detecting radon gas concentration according to an embodiment of the present invention;
[Description of Signs for Important Parts of Drawing]
1: detection device, 2: pumping means,
3: first proportional detection means, 4: connection pipe,
5: alpha particle releasing material, 6: second proportional detection means,
7: calculation means, 8: preamplification means,
9: amplification means, 10: negative electrode,
11: anode, 12: insulated tube,
13: silicon tube, 14: display means.
Claims (11)
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| KR1020080009920A KR100936298B1 (en) | 2008-01-31 | 2008-01-31 | A Process of Detection for A Radon Gas-Density and The Device |
| PCT/KR2008/000961 WO2009096623A1 (en) | 2008-01-31 | 2008-02-19 | A process of detection for a radon gas-density and the device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
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| KR1020080009920A KR100936298B1 (en) | 2008-01-31 | 2008-01-31 | A Process of Detection for A Radon Gas-Density and The Device |
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| Publication Number | Publication Date |
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| KR20090084003A true KR20090084003A (en) | 2009-08-05 |
| KR100936298B1 KR100936298B1 (en) | 2010-01-12 |
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| WO (1) | WO2009096623A1 (en) |
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| KR101789091B1 (en) | 2015-08-28 | 2017-10-23 | 주식회사 베터라이프 | Measuring device of Radon gas in real time and operating method thereof |
| KR20190109083A (en) | 2018-03-16 | 2019-09-25 | 인하대학교 산학협력단 | Pfm buck converter using level shifting |
| KR20230144411A (en) | 2022-04-07 | 2023-10-16 | 한국과학기술원 | Real-time discriminative detection apparatus for radon and thoron using air flow delay |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4055762A (en) * | 1976-03-25 | 1977-10-25 | The United States Of America As Represented By The Secretary Of The Interior | Radon daughter dosimeter |
| US4864143A (en) * | 1986-04-08 | 1989-09-05 | Pai Hsiang L | Time-average radon daughters (WL) dosimeter for mines, indoor and environment survey |
| JPH10186036A (en) * | 1996-10-08 | 1998-07-14 | Seiichi Yamamoto | Radon concentration measuring method and its device |
| KR20010103440A (en) * | 2000-05-10 | 2001-11-23 | 이종훈 | Online Radon Concentration Monitoring System |
| JP3930234B2 (en) * | 2000-08-25 | 2007-06-13 | 独立行政法人科学技術振興機構 | Radon concentration measuring apparatus and method |
| JP4330904B2 (en) | 2003-03-14 | 2009-09-16 | 株式会社東芝 | Radiation detection method and apparatus |
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- 2008-01-31 KR KR1020080009920A patent/KR100936298B1/en not_active IP Right Cessation
- 2008-02-19 WO PCT/KR2008/000961 patent/WO2009096623A1/en active Application Filing
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| WO2009096623A1 (en) | 2009-08-06 |
| KR100936298B1 (en) | 2010-01-12 |
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