CN112346106A - Radon measuring device and method for small air pulse ionization chamber - Google Patents
Radon measuring device and method for small air pulse ionization chamber Download PDFInfo
- Publication number
- CN112346106A CN112346106A CN202011305989.9A CN202011305989A CN112346106A CN 112346106 A CN112346106 A CN 112346106A CN 202011305989 A CN202011305989 A CN 202011305989A CN 112346106 A CN112346106 A CN 112346106A
- Authority
- CN
- China
- Prior art keywords
- ionization chamber
- radon
- circuit
- pulse
- circuit board
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- SYUHGPGVQRZVTB-UHFFFAOYSA-N radon atom Chemical compound [Rn] SYUHGPGVQRZVTB-UHFFFAOYSA-N 0.000 title claims abstract description 49
- 229910052704 radon Inorganic materials 0.000 title claims abstract description 48
- 238000000034 method Methods 0.000 title claims description 16
- 238000005259 measurement Methods 0.000 claims abstract description 26
- 230000003321 amplification Effects 0.000 claims abstract description 13
- 238000003199 nucleic acid amplification method Methods 0.000 claims abstract description 13
- 238000004891 communication Methods 0.000 claims abstract description 10
- 238000001514 detection method Methods 0.000 claims abstract description 8
- 230000000149 penetrating effect Effects 0.000 claims abstract 2
- WSFSSNUMVMOOMR-UHFFFAOYSA-N Formaldehyde Chemical compound O=C WSFSSNUMVMOOMR-UHFFFAOYSA-N 0.000 claims description 51
- 150000002500 ions Chemical class 0.000 claims description 41
- 239000005416 organic matter Substances 0.000 claims description 15
- 238000001914 filtration Methods 0.000 claims description 14
- 239000002245 particle Substances 0.000 claims description 14
- 239000000428 dust Substances 0.000 claims description 12
- 230000007613 environmental effect Effects 0.000 claims description 9
- 230000008569 process Effects 0.000 claims description 9
- 230000005684 electric field Effects 0.000 claims description 8
- 239000012528 membrane Substances 0.000 claims description 8
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 claims description 6
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 6
- 230000009471 action Effects 0.000 claims description 4
- 230000005669 field effect Effects 0.000 claims description 4
- 230000005262 alpha decay Effects 0.000 claims description 3
- 238000004458 analytical method Methods 0.000 claims description 3
- 230000004323 axial length Effects 0.000 claims description 3
- 239000003990 capacitor Substances 0.000 claims description 3
- 239000001569 carbon dioxide Substances 0.000 claims description 3
- 229910002092 carbon dioxide Inorganic materials 0.000 claims description 3
- 238000009792 diffusion process Methods 0.000 claims description 3
- 229910052742 iron Inorganic materials 0.000 claims description 3
- 230000033001 locomotion Effects 0.000 claims description 3
- 239000000463 material Substances 0.000 claims description 3
- 230000006798 recombination Effects 0.000 claims description 3
- 238000005215 recombination Methods 0.000 claims description 3
- 238000001179 sorption measurement Methods 0.000 claims description 3
- 229910001220 stainless steel Inorganic materials 0.000 claims description 3
- 239000010935 stainless steel Substances 0.000 claims description 3
- 239000002184 metal Substances 0.000 claims 2
- 229910052751 metal Inorganic materials 0.000 claims 2
- 238000004519 manufacturing process Methods 0.000 abstract description 3
- 239000007789 gas Substances 0.000 description 4
- 208000019155 Radiation injury Diseases 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- 238000012937 correction Methods 0.000 description 2
- 230000005611 electricity Effects 0.000 description 2
- 238000011160 research Methods 0.000 description 2
- 206010058467 Lung neoplasm malignant Diseases 0.000 description 1
- 230000002159 abnormal effect Effects 0.000 description 1
- 239000000443 aerosol Substances 0.000 description 1
- 239000004566 building material Substances 0.000 description 1
- 239000000969 carrier Substances 0.000 description 1
- 230000032823 cell division Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000026058 directional locomotion Effects 0.000 description 1
- 230000036541 health Effects 0.000 description 1
- 239000011261 inert gas Substances 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 210000004072 lung Anatomy 0.000 description 1
- 201000005202 lung cancer Diseases 0.000 description 1
- 208000020816 lung neoplasm Diseases 0.000 description 1
- 238000000691 measurement method Methods 0.000 description 1
- 239000002923 metal particle Substances 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 210000002345 respiratory system Anatomy 0.000 description 1
- 230000004044 response Effects 0.000 description 1
- 239000002689 soil Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 239000008399 tap water Substances 0.000 description 1
- 235000020679 tap water Nutrition 0.000 description 1
Images
Classifications
-
- 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
- G01T1/167—Measuring radioactive content of objects, e.g. contamination
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
- G01D21/00—Measuring or testing not otherwise provided for
- G01D21/02—Measuring two or more variables by means not covered by a single other subclass
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
- G01N33/0004—Gaseous mixtures, e.g. polluted air
- G01N33/0009—General constructional details of gas analysers, e.g. portable test equipment
- G01N33/0027—General constructional details of gas analysers, e.g. portable test equipment concerning the detector
- G01N33/0031—General constructional details of gas analysers, e.g. portable test equipment concerning the detector comprising two or more sensors, e.g. a sensor array
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
- G01N33/0004—Gaseous mixtures, e.g. polluted air
- G01N33/0009—General constructional details of gas analysers, e.g. portable test equipment
- G01N33/0027—General constructional details of gas analysers, e.g. portable test equipment concerning the detector
- G01N33/0036—General constructional details of gas analysers, e.g. portable test equipment concerning the detector specially adapted to detect a particular component
- G01N33/004—CO or CO2
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
- G01N33/0004—Gaseous mixtures, e.g. polluted air
- G01N33/0009—General constructional details of gas analysers, e.g. portable test equipment
- G01N33/0027—General constructional details of gas analysers, e.g. portable test equipment concerning the detector
- G01N33/0036—General constructional details of gas analysers, e.g. portable test equipment concerning the detector specially adapted to detect a particular component
- G01N33/0047—Organic compounds
-
- 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
- G01T1/185—Measuring radiation intensity with ionisation chamber arrangements
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J47/00—Tubes for determining the presence, intensity, density or energy of radiation or particles
- H01J47/02—Ionisation chambers
Landscapes
- Chemical & Material Sciences (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- General Physics & Mathematics (AREA)
- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Analytical Chemistry (AREA)
- Combustion & Propulsion (AREA)
- Food Science & Technology (AREA)
- Medicinal Chemistry (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Spectroscopy & Molecular Physics (AREA)
- Molecular Biology (AREA)
- High Energy & Nuclear Physics (AREA)
- Measurement Of Radiation (AREA)
Abstract
The invention relates to the technical field of radon measurement, in particular to a small-sized radon measurement device with an air pulse ionization chamber, which comprises an ionization chamber with a cylindrical structure, wherein an end cover is arranged at one opening end of the ionization chamber, air holes are formed in the end cover, a wire mesh is arranged at the other opening end of the ionization chamber, a through hole penetrating through the end cover is formed in the center of the end cover, a collecting electrode extends into the ionization chamber from the through hole and extends to a position close to the wire mesh, one end, far away from the wire mesh, of the collecting electrode is electrically connected with a circuit board, the circuit board is arranged on the end cover through a support column, an acquisition circuit, a front amplification circuit, a rear main amplification circuit, a discrimination circuit, a main control unit and a communication module are arranged on the circuit board, a high-voltage power supply is connected to the shell of the ionization chamber with the cylindrical structure, the two ends of, the radon concentration is detected by inserting the collecting electrode into the ionization chamber, and the radon concentration detection device is simple in structure and low in manufacturing cost.
Description
Technical Field
The invention relates to the technical field of radon measurement, in particular to a small-sized radon measurement device for an air pulse ionization chamber and a measurement method.
Background
The radon is inert gas and inactive in chemical property, radon atoms can spontaneously decay to become radon daughter which is metal particles with charges and can be attached to tiny particles in the air. The aerosol particles in the air are carriers of radon daughters, the particles attached with the radon daughters are all remained and deposited in respiratory tracts and lungs after being inhaled into human bodies, alpha particles generated by the continuous decay of the radon daughters have high energy, can destroy or change the molecular structure of DNA in cells, inhibit the copy function of the DNA, cause abnormal cell division and finally can develop into lung cancer. Research by scientists shows that the radiation injury of radon to human bodies accounts for more than 50 percent of all radiation injury suffered by the radon in the life of the human bodies.
Radon is ubiquitous and is distributed in our living environment, what we need to be particularly alert is indoor radon, which can come from soil under the foundation, can come from various building materials, or come from air and tap water.
However, the radon measuring instrument is mainly used in the fields of industry, commerce, scientific research and the like due to the reasons of large volume, high price, complex operation and the like, and cannot be widely popularized as a popular product.
Disclosure of Invention
The invention provides a small-sized air pulse ionization chamber radon measuring device and a measuring method, which improve the volume, the structure and the performance of a radon measuring instrument, save the manufacturing cost, are beneficial to the popularization of products, and enable families to use the device, thereby protecting the health of people.
In order to achieve the purpose, the invention provides the following technical scheme:
the utility model provides a small-size air pulse ionization chamber emanometer device, is including the display screen that is used for showing the measured data and the ionization chamber of tubular structure, and the end cover is installed to an open end of ionization chamber, be provided with the bleeder vent on the end cover, wire mesh is installed to the other end opening of ionization chamber, the central point department of putting of end cover is provided with the through-hole that runs through the end cover, and the collecting electrode stretches into the ionization chamber from this through-hole to stretch into and be close to wire mesh department, the collecting electrode is kept away from wire mesh's one end and is connected with the circuit board electricity, and the circuit board passes through the support column and installs on the end cover, be provided with acquisition circuit, preceding amplifier circuit, rear end main amplifier circuit, discriminate circuit, main control unit and communication module on the circuit board.
Furthermore, one end, close to the circuit board, of the collecting electrode is sleeved with a sleeve made of an insulating high-pressure-resistant material, the sleeve is installed on the circuit board, and the axial length of the sleeve is larger than the distance from the circuit board to the end cover, so that one end, far away from the circuit board, of the sleeve extends into the ionization chamber.
Preferably, one end of the ionization chamber, which is far away from the end cover, is provided with two annular convex parts around the circumference of the inner wall of the ionization chamber, and the wire mesh is arranged between the two annular convex parts.
Furthermore, dust filtering membranes are installed at openings at two ends of the ionization chamber.
Preferably, the ionization chamber is assembled by two sections of cylinders through bolts.
Furthermore, a temperature and humidity sensor is installed outside the ionization chamber and electrically connected with the main control unit, so that the ambient temperature and humidity conditions can be detected at any time.
Further, an organic matter detector and a formaldehyde detector are installed outside the ionization chamber, and both the organic matter detector and the formaldehyde detector are connected to the main control unit, so that indoor organic matters and formaldehyde can be detected constantly.
Preferably, the wall of the ionization chamber is made of iron sheet or stainless steel.
Preferably, the circuit board is adjacent to the ionization chamber opening to which the end cap is mounted, and a gap remains between the circuit board and the ionization chamber opening.
A small air pulse ionization chamber measuring method comprises the following steps:
step 1: air enters the ionization chamber from two openings of the ionization chamber;
step 2: before entering the ionization chamber, most of dust and radon daughter in the air are filtered by dust filtering membranes at two ends of the ionization chamber;
and step 3: radon in the ionization chamber decays to form a series of daughter, alpha particles generated by alpha decay directly ionize an air medium to generate an electron and ion pair; the electron and ion pairs capture kinetic energy from incident particles, run in gas and collide with gas molecules to generate physical processes of diffusion, adsorption, recombination, drift and the like;
and 4, step 4: when the pulse ionization chamber works, high voltage is applied to the shell of the ionization chamber to serve as an anode A, the collecting electrode serves as a cathode K, a directional electric field is generated inside the ionization chamber, and 4 pi detection is realized on alpha particles;
and 5: the electrons and the ions drift towards two poles respectively under the action of an electric field, induced charges appear on the collecting electrode in the drifting process, the more positive ions are close to the collecting electrode, the more induced charges are, the more charges are accumulated on a capacitor C of the collecting electrode to the ground, and the maximum value is reached when all the positive ions and the negative ions are collected.
Step 6: the charge-directed movement forms a current pulse, which starts with the generation of an ion pair and ends with the collection of the ion pair in its entirety, which current pulse causes the field effect transistor connected to the collecting electrode to conduct and to form a voltage pulse across the load resistor. Its amplitude U is:
q is the amount of charge collected and Cd is the collector to ground capacitance.
And 7: the pre-amplification circuit is used for pre-amplifying a very weak pulse signal output by the pulse ionization chamber; the output end of the preamplifier circuit is connected with the main amplifier through a shielding cable; the preamplifier of the system adopts a charge sensitive amplifier, mainly carries out distortion-free initial linear amplification on a weak signal output from a detector and provides the weak signal to a subsequent circuit, wherein the signal is generally dozens of millivolts to hundreds of millivolts, and the pulse width is narrow.
And 8: the main amplifying circuit amplifies the output of the pre-amplifying circuit again to enable the signal to meet the measurement and analysis of a subsequent circuit; the main amplifier amplifies the small signals to the required amplitude, reforms the signal shape, and performs filtering forming, so as to amplify useful signals, reduce noise, improve the signal-to-noise ratio, be suitable for the measurement of subsequent circuits, and not lose useful information as much as possible in the process; the amplitude of the output voltage of the main amplifier is controlled to be about 0.5-4V, and the amplification factor is controlled to be about 50-100 times.
And step 9: the discrimination circuit completes further filtering of the signals, filters interference signals by setting a discrimination threshold, converts the signals into square wave pulses and sends the square wave pulses to the main control unit.
Step 10: the temperature and humidity sensor collects environmental temperature and humidity indexes and sends the environmental temperature and humidity indexes to the main control unit; the temperature and humidity of the medium air in the ionization chamber mainly affect the effective electron-ion logarithm generated by ionization, thereby affecting the magnitude of the output of an electric signal, and the electric signal at a threshold critical point may not be identified due to the fact that the signal is too weak. Collecting the influence of temperature and humidity value correction environment on radon concentration measurement, and correcting radon concentration measurement value according to a fitting equation input in advance.
Step 11: the air quality detection sensor collects data such as environmental organic matter concentration and formaldehyde concentration and sends the data to the main control unit.
Step 12: the main control unit module is combined with a relevant circuit to complete functions of data acquisition, channel control, parameter setting, communication with an upper computer and the like; firstly, recording output pulses of a discrimination circuit, and converting the output pulses into radon concentration; meanwhile, the temperature and humidity of the environment can be read through a temperature and humidity measuring module, and the organic matter concentration, the formaldehyde concentration and the equivalent carbon dioxide concentration of the environment can also be read through an organic matter and formaldehyde measuring module; and then the WIFI module and the RS485 module are communicated with the mobile phone APP and PC end software to finish the uploading of data.
Step 13: the basic measurement data are displayed on a display screen.
Step 14: data is wirelessly transmitted to a mobile phone or a PC terminal through the WIFI module for communication; and the measured value can be transmitted to a PC terminal through an RS485 module in a wired mode, so that the measured value can be monitored on line.
Compared with the prior art, the invention has the beneficial effects that: 1. the radon concentration detection device adopts the ionization chamber with the cylinder structure with the two air-permeable ends, the radon concentration detection device is inserted into the ionization chamber through the collecting electrode, the structure is simple, the manufacturing cost is low, the two air-permeable ends of the ionization chamber with the cylinder structure realize the quick response to the radon concentration change.
2. Through the installation dust filtration membrane at the both ends opening part of ionization chamber to the effectual influence of dust to the ionization chamber of having avoided.
Drawings
FIG. 1 is a schematic view of the overall structure of the present invention;
FIG. 2 is a detailed schematic view of the end cap of the present invention;
FIG. 3 is a detailed schematic view of the wire mesh of the present invention;
FIG. 4 is a schematic diagram of the system of the present invention;
description of reference numerals: 1. a circuit board; 2. a support pillar; 3. a sleeve; 4. a dust filtering membrane; 5. a collecting electrode; 6. an ionization chamber; 7. a wire mesh; 8. an annular boss; 9. and (4) end covers.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Referring to figures 1 to 4: the utility model provides a small-size air pulse ionization chamber emanometer, includes tubular structure's ionization chamber 6, and end cover 9 is installed to an open end of ionization chamber 6, be provided with the bleeder vent on the end cover 9, wire mesh 7 is installed to the other end opening of ionization chamber 6, the central point department of putting of end cover 9 is provided with the through-hole that runs through end cover 9, and collecting electrode 5 stretches into in ionization chamber 6 from this through-hole to stretch into and be close to wire mesh 7 department, collecting electrode 5 keeps away from the one end and the circuit board 1 electricity of wire mesh 7 and being connected, and circuit board 1 passes through support column 2 and installs on the end cover 9, be provided with acquisition circuit, preamplification amplifier circuit, rear end main amplifier circuit, discriminate circuit, main control unit and communication module on the circuit board 1, 6 shells of ionization chamber insert high voltage power supply.
One end of the collecting electrode 5, which is close to the circuit board 1, is sleeved with a sleeve 3 made of an insulating high-pressure-resistant material, the sleeve 3 is installed on the circuit board 1, and the axial length of the sleeve 3 is greater than the distance from the circuit board 1 to the end cover 9, so that one end, which is far away from the circuit board 1, of the sleeve 3 extends into the ionization chamber 6.
One end of the ionization chamber 6, which is far away from the end cover 9, is provided with two annular convex parts 8 around the circumference of the inner wall of the ionization chamber 6, and the wire mesh 7 is arranged between the two annular convex parts 8.
And dust filtering membranes 4 are respectively arranged at openings at two ends of the ionization chamber 6.
The ionization chamber 6 is assembled by two sections of cylinders through bolts.
And a temperature and humidity sensor is arranged outside the ionization chamber 6 and is electrically connected with the main control unit, so that the ambient temperature and humidity conditions can be detected at any time.
An organic matter detector and a formaldehyde detector are arranged outside the ionization chamber 6, and both the organic matter detector and the formaldehyde detector are connected into the main control unit, so that indoor organic matters and formaldehyde can be detected constantly.
The wall of the ionization chamber 6 is made of iron sheet or stainless steel.
The circuit board 1 is close to the opening of the ionization chamber 6 provided with the end cover 9, and a gap is reserved between the circuit board 1 and the opening of the ionization chamber 6, so that the pulse signal attenuation and interference are effectively avoided.
When the ionization chamber 6 works, high voltage is added to the ionization chamber 6 to serve as a positive electrode, the collecting electrode 5 serves as a negative electrode, a directional electric field is generated in the ionization chamber 6, and charged ions formed by decay of radon and daughters thereof ionize air to generate electron and ion pairs. The electrons and the ions drift towards two poles respectively under the action of an electric field, induced charges appear on the collecting electrode 5 in the drifting process, the more positive ions are close to the collecting electrode 5, the more induced charges are, the more charges are accumulated on the capacitance of the collecting electrode 5 to the ground, and the maximum value is reached when all the positive ions and the negative ions are collected. The directional movement of the charges forms a current pulse, which causes a field effect transistor connected with the collecting electrode 5 to be conducted, and a voltage pulse is formed on the load resistor, the pulse starts from the generation of ion pairs, and finally the ion pairs are all collected, and the signal processing circuit collects the voltage pulse to measure the radiant quantity and energy of the charged particles.
A small air pulse ionization chamber measuring method comprises the following steps:
step 1: air enters the ionization chamber 6 from two openings of the ionization chamber 6;
step 2: before entering the ionization chamber 6, most of dust and radon daughter in the air are filtered by dust filtering membranes 4 at two ends of the ionization chamber 6;
and step 3: radon in the ionization chamber 6 decays to form a series of daughter, alpha particles generated by alpha decay directly ionize an air medium to generate an electron and ion pair; the electron and ion pairs capture kinetic energy from incident particles, run in gas and collide with gas molecules to generate physical processes of diffusion, adsorption, recombination, drift and the like;
and 4, step 4: when the pulse ionization chamber 6 works, high voltage is applied to the outer shell of the ionization chamber 6 to serve as an anode A, the collecting electrode 5 serves as a cathode K, a directional electric field is generated in the ionization chamber 6, and 4 pi detection is realized on alpha particles;
and 5: electrons and ions drift towards two poles respectively under the action of an electric field, induced charges appear on the collecting electrode 5 in the drifting process, the more positive ions are close to the collecting electrode 5, the more induced charges are, the more charges are accumulated on the capacitor C of the collecting electrode 5 to the ground, and the maximum value is reached when all the positive ions and the negative ions are collected.
Step 6: the charge directed movement forms a current pulse which starts with the generation of the ion pair and ends with the collection of the ion pair in its entirety, the current pulse causing the field effect transistor connected to the collecting electrode 5 to conduct and a voltage pulse across the load resistance. Its amplitude U is:
q is the amount of charge collected and Cd is the collector to ground capacitance.
And 7: the pre-amplification circuit pre-amplifies a very weak pulse signal output by the pulse ionization chamber 6; the output end of the preamplifier circuit is connected with the main amplifier through a shielding cable; the preamplifier of the system adopts a charge sensitive amplifier, mainly carries out distortion-free initial linear amplification on a weak signal output from a detector and provides the weak signal to a subsequent circuit, wherein the signal is generally dozens of millivolts to hundreds of millivolts, and the pulse width is narrow.
And 8: the main amplifying circuit amplifies the output of the pre-amplifying circuit again to enable the signal to meet the measurement and analysis of a subsequent circuit; the main amplifier amplifies the small signals to the required amplitude, reforms the signal shape, and performs filtering forming, so as to amplify useful signals, reduce noise, improve the signal-to-noise ratio, be suitable for the measurement of subsequent circuits, and not lose useful information as much as possible in the process; the amplitude of the output voltage of the main amplifier is controlled to be about 0.5-4V, and the amplification factor is controlled to be about 50-100 times.
And step 9: the discrimination circuit completes further filtering of the signals, filters interference signals by setting a discrimination threshold, converts the signals into square wave pulses and sends the square wave pulses to the main control unit.
Step 10: the temperature and humidity sensor collects environmental temperature and humidity indexes and sends the environmental temperature and humidity indexes to the main control unit; the temperature and humidity of the medium air in the ionization chamber 6 mainly affect the effective electron-ion logarithm generated by ionization, thereby affecting the magnitude of the output of an electric signal, and the electric signal at the threshold critical point may not be identified due to too weak signal. Collecting the influence of temperature and humidity value correction environment on radon concentration measurement, and correcting radon concentration measurement value according to a fitting equation input in advance.
Step 11: the air quality detection sensor collects data such as environmental organic matter concentration and formaldehyde concentration and sends the data to the main control unit.
Step 12: the main control unit module is combined with a relevant circuit to complete functions of data acquisition, channel control, parameter setting, communication with an upper computer and the like; firstly, recording output pulses of a discrimination circuit, and converting the output pulses into radon concentration; meanwhile, the temperature and humidity of the environment can be read through a temperature and humidity measuring module, and the organic matter concentration, the formaldehyde concentration and the equivalent carbon dioxide concentration of the environment can also be read through an organic matter and formaldehyde measuring module; and then the WIFI module and the RS485 module are communicated with the mobile phone APP and PC end software to finish the uploading of data.
Step 13: the basic measurement data are displayed on a display screen.
Step 14: data is wirelessly transmitted to a mobile phone or a PC terminal through the WIFI module for communication; and the measured value can be transmitted to a PC terminal through an RS485 module in a wired mode, so that the measured value can be monitored on line.
It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference sign in a claim should not be construed as limiting the claim concerned.
Furthermore, it should be understood that although the present description refers to embodiments, not every embodiment may contain only a single embodiment, and such description is for clarity only, and those skilled in the art should integrate the description, and the embodiments may be combined as appropriate to form other embodiments understood by those skilled in the art.
Claims (10)
1. The utility model provides a radon measuring is with small-size air ion pulse ionization chamber which characterized in that: comprises an ionization chamber (6) with a cylinder structure, an end cover (9) is arranged at one opening end of the ionization chamber (6), the end cover (9) is provided with an air hole, the other end opening of the ionization chamber (6) is provided with a wire mesh (7), a through hole penetrating through the end cover (9) is arranged at the central position of the end cover (9), the collecting electrode (5) extends into the ionization chamber (6) from the through hole, and extends into the position close to the metal wire mesh (7), one end of the collecting electrode (5) far away from the metal wire mesh (7) is electrically connected with the circuit board (1), the circuit board (1) is arranged on the end cover (9) through a supporting column (2), the ionization chamber is characterized in that the circuit board (1) is provided with an acquisition circuit, a pre-amplification circuit, a rear-end main amplification circuit, a discrimination circuit, a main control unit and a communication module, and a shell of the ionization chamber (6) is connected with a high-voltage power supply.
2. The miniature air ion pulse ionization chamber for radon measurement as set forth in claim 1, wherein: one end of the collecting electrode (5) close to the circuit board (1) is sleeved with a sleeve (3) made of an insulating high-pressure-resistant material, the sleeve (3) is installed on the circuit board (1), and the axial length of the sleeve (3) is larger than the distance from the circuit board (1) to the end cover (9), so that one end, far away from the circuit board (1), of the sleeve (3) extends into the ionization chamber (6).
3. The miniature air ion pulse ionization chamber for radon measurement as set forth in claim 1, wherein: one end of the ionization chamber (6), which is far away from the end cover (9), is provided with two annular convex parts (8) around the circumference of the inner wall of the ionization chamber (6), and the wire mesh (7) is arranged between the two annular convex parts (8).
4. The miniature air ion pulse ionization chamber for radon measurement as set forth in claim 1, wherein: and dust filtering membranes (4) are respectively installed at openings at two ends of the ionization chamber (6).
5. The miniature air ion pulse ionization chamber for radon measurement as set forth in claim 1, wherein: the ionization chamber (6) is assembled by two sections of cylinders through bolts.
6. The miniature air ion pulse ionization chamber for radon measurement as set forth in claim 1, wherein: the wall of the ionization chamber (6) is made of iron sheet or stainless steel.
7. The miniature air ion pulse ionization chamber for radon measurement as set forth in claim 1, wherein: the circuit board (1) is close to an opening of the ionization chamber (6) provided with the end cover (9), and a gap is reserved between the circuit board (1) and the opening of the ionization chamber (6).
8. A small air ion pulse ionization chamber for radon measurement as claimed in any one of claims 1 to 7 wherein: and a temperature and humidity sensor is arranged outside the ionization chamber (6) and is electrically connected with the main control unit.
9. A small air ion pulse ionization chamber for radon measurement as claimed in any one of claims 1 to 7 wherein: an organic matter detector and a formaldehyde detector are arranged outside the ionization chamber (6), and both the organic matter detector and the formaldehyde detector are connected to the main control unit.
10. A method for measuring a small air pulse ionization chamber is characterized by comprising the following steps: the method comprises the following steps:
step 1: air enters the ionization chamber (6) from two openings of the ionization chamber (6);
step 2: before entering the ionization chamber (6), most of dust and radon daughter in the air are filtered by dust filtering membranes (4) at two ends of the ionization chamber (6);
and step 3: radon in the ionization chamber (6) decays to form a series of daughter, alpha particles generated by alpha decay directly ionize an air medium to generate an electron and ion pair; the electron and ion pairs capture kinetic energy from incident particles, run in gas and collide with gas molecules to generate physical processes of diffusion, adsorption, recombination, drift and the like;
and 4, step 4: when the pulse ionization chamber (6) works, high voltage is applied to the shell of the ionization chamber (6) to serve as an anode A, the collecting electrode (5) serves as a cathode K, a directional electric field is generated in the ionization chamber (6), and alpha particles are detected in a 4 pi mode;
and 5: the electrons and the ions drift towards two poles respectively under the action of an electric field, in the drifting process, induced charges appear on the collecting electrode (5), the more positive ions are close to the collecting electrode (5), the more induced charges are, the more charges are accumulated on a capacitor C of the collecting electrode (5) to the ground, and the maximum value is reached when the positive ions and the negative ions are all collected;
step 6: the charge-directed movement forms a current pulse which starts with the generation of the ion pair and ends with the collection of the ion pair in its entirety, the current pulse causing the field effect transistor connected to the collecting electrode (5) to conduct and a voltage pulse to be formed across the load resistor. Its amplitude U is:
q is the amount of charge collected, Cd is the capacitance of the collector to ground;
and 7: the pre-amplification circuit is used for pre-amplifying a very weak pulse signal output by the pulse ionization chamber (6); the output end of the pre-amplification circuit is connected with the main amplifier through a shielded cable; the preamplifier adopts a charge sensitive amplifier;
and 8: the main amplifying circuit amplifies the output of the pre-amplifying circuit again to enable the signal to meet the measurement and analysis of a subsequent circuit; the main amplifier amplifies the small signals to the required amplitude, the signal shape is transformed, filtering forming is carried out, the amplitude of the output voltage of the main amplifier is controlled to be about 0.5-4V, and the amplification factor is controlled to be about 50-100.
And step 9: the discrimination circuit completes further filtering of the signals, filters interference signals by setting a discrimination threshold, converts the signals into square wave pulses and sends the square wave pulses to the main control unit.
Step 10: the temperature and humidity sensor collects environmental temperature and humidity indexes and sends the environmental temperature and humidity indexes to the main control unit; the temperature and humidity of the medium air in the ionization chamber (6) mainly influence the effective electron-ion logarithm generated by ionization, the influence of the environment on radon concentration measurement is corrected by collecting the temperature and humidity values, and then the radon concentration measurement value is corrected according to a pre-input fitting equation.
Step 11: the air quality detection sensor collects data such as environmental organic matter concentration and formaldehyde concentration and sends the data to the main control unit.
Step 12: the main control unit module is combined with a relevant circuit to complete functions of data acquisition, channel control, parameter setting, communication with an upper computer and the like; firstly, recording output pulses of a discrimination circuit, and converting the output pulses into radon concentration; simultaneously, the temperature and humidity of the environment are read through a temperature and humidity measuring module, and the organic matter concentration, the formaldehyde concentration and the equivalent carbon dioxide concentration of the environment are read through an organic matter and formaldehyde measuring module; and then the WIFI module and the RS485 module are communicated with the mobile phone APP and PC end software to finish the uploading of data.
Step 13: the basic measurement data are displayed on a display screen.
Step 14: data is wirelessly transmitted to a mobile phone or a PC terminal through the WIFI module for communication; and the measured value can be transmitted to a PC terminal through an RS485 module in a wired mode, so that the measured value can be monitored on line.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011305989.9A CN112346106A (en) | 2020-11-19 | 2020-11-19 | Radon measuring device and method for small air pulse ionization chamber |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011305989.9A CN112346106A (en) | 2020-11-19 | 2020-11-19 | Radon measuring device and method for small air pulse ionization chamber |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN112346106A true CN112346106A (en) | 2021-02-09 |
Family
ID=74364354
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202011305989.9A Pending CN112346106A (en) | 2020-11-19 | 2020-11-19 | Radon measuring device and method for small air pulse ionization chamber |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN112346106A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114797405A (en) * | 2022-06-09 | 2022-07-29 | 青岛儒海蓝色科技股份有限公司 | Physical adsorption heat-resistant radioactive pollution purification type monitoring equipment |
-
2020
- 2020-11-19 CN CN202011305989.9A patent/CN112346106A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114797405A (en) * | 2022-06-09 | 2022-07-29 | 青岛儒海蓝色科技股份有限公司 | Physical adsorption heat-resistant radioactive pollution purification type monitoring equipment |
| CN114797405B (en) * | 2022-06-09 | 2022-09-16 | 青岛儒海蓝色科技股份有限公司 | Physical adsorption heat-resistant radioactive pollution purification type monitoring equipment |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN201488977U (en) | Quick air radon concentration measuring device based on air impulse ionization chamber | |
| CN202362462U (en) | Exhaust type continuous radon gas detector | |
| CN103364480B (en) | Detection system for IMS (Ion Mobility Spectrometry) explosives | |
| US5550381A (en) | Event counting alpha detector | |
| JP5052733B2 (en) | Detector for alpha particle radiation in air | |
| CN112346106A (en) | Radon measuring device and method for small air pulse ionization chamber | |
| CN105784555A (en) | Dust concentration detection device and dust concentration detection method | |
| JP2010133879A (en) | Radiation measuring apparatus | |
| CN105353397B (en) | A kind of radon and thorium emanation continuous measuring device and method based on static collection | |
| CN105353398A (en) | System and method for on-line measurement of radon and thoron, and daughter concentration therefor | |
| CN214375290U (en) | Small-size air pulse ionization chamber emanometer device | |
| CN103487824B (en) | A kind of radon daughter sampling apparatus based on high-voltage corona discharge | |
| KR101935880B1 (en) | Radiation monitoring apparatus using ination chamber | |
| CN206710365U (en) | A kind of portable soil heavy metal detection means | |
| CN205719880U (en) | Concentration of dust detection device | |
| CN107991586A (en) | A kind of high-tension electricity equipment leakage detection device and its implementation | |
| CN213846620U (en) | Charge sensitive preamplification circuit of underwater gamma spectrometer | |
| CN211348030U (en) | Anion sensor based on air conductivity detection | |
| CN211825826U (en) | FAIMS ion detector | |
| CN209264968U (en) | A kind of flow-type ionization chamber measuring tritium gas | |
| CN2852151Y (en) | Device for detecting radon and its daughter alpha energy spectrum using normal pressure air impulse ionization chamber | |
| CN114527162A (en) | Negative ion concentration detection device and detection method | |
| CN102854202A (en) | Test system of energy of static state substance | |
| CN106970125A (en) | A kind of portable soil heavy metal detection means | |
| CN101105484B (en) | Argon gas discharging detection device and method |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |