CN85107800A - Radon and daughter detection device thereof and method of work in the earth - Google Patents
Radon and daughter detection device thereof and method of work in the earth Download PDFInfo
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- CN85107800A CN85107800A CN 85107800 CN85107800A CN85107800A CN 85107800 A CN85107800 A CN 85107800A CN 85107800 CN85107800 CN 85107800 CN 85107800 A CN85107800 A CN 85107800A CN 85107800 A CN85107800 A CN 85107800A
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- radon
- ionization chamber
- daughter
- gatherer
- cup
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Abstract
A kind of is radon detection device in the earth of detector with the air pulse ionization chamber, by being that the α digital radiation instrument of detector and radon and daughter gatherer thereof constitute with the air pulse ionization chamber.Air pulse ionization chamber α digital radiation instrument has characteristics such as detector area is big, decontamination is easy; Radon and daughter gatherer thereof can be made of large tracts of land natural, static α cup or activated charcoal α cup etc.This device can be used for instantaneous detecting radon, can be used for the α actinometry of various accumulations survey radons etc. again.Field work efficient height, easy to use.
Description
The present invention for a kind of be the α radiation detector assembly of detector with the air pulse ionization chamber, be mainly used in the radiometric prospecting field α radiation of surveying radon and daughter in the soil, thereby solve relevant geological problem.
In the prior art, the α radiation gauge of radon and daughter generally adopts Z in the open-air various earth that use
nS(A
g) scintillator, gold silicon surface barrier semiconductor make the α radiation detector.Though use these α radiation gauges can solve many geological problems, have the following disadvantages:
1.Z
nS(A
g) scintillator and metallic silicon surface barrier semiconductor make detector and all must use under the lucifuge condition of strictness, thereby bring many inconvenience for the structural design and the field operation of instrument.
2. in measuring process, above-mentioned two kinds of detectors all are subjected to the pollution of radon and daughter easily, and the instrument truth of a matter is increased, and influence the reliability of measurement result.
3. above-mentioned two kinds of detector fields decontaminate handle all very difficult.Still can't get rid of at present the pollution on the gold silicon surface barrier semiconductor detector, and to Z
nS(A
g) scintillator after (normally changing the scintillation chamber) handled in decontamination, need lucifuge to wait for the long period (being no less than 15 minutes), just can restart work, field work efficient is reduced.
4. the size and the shape of radon and daughter gatherer thereof are restricted, and the sensitivity of measurement is affected.
5. existing open-air α radiation gauge only is applicable to a kind of method usually, and purposes is single.
The objective of the invention is to overcome the above-mentioned deficiency of existing open-air α radiation gauge, providing a kind of is detector with the air pulse ionization chamber, is the open-air α radiation detector assembly of radon and daughter gatherer thereof with the big α cup of surface area.It not only has highly sensitive, and decontamination easily, fast, does not need the characteristics of lucifuge, and good mechanical property, and cost is low, the power consumptive province, and outdoor operation method is easy.Especially the air pulse ionization chamber α digital radiation instrument among the present invention has the characteristics of a tractor serves several purposes, and it both can be used for conventional emanation prospecting (instantaneous detecting radon), promptly directly radon gas in the earth is introduced ionization chamber in the open air and is carried out the α measurement; Can be used for accumulation again and survey radon, be about to various radons and daughter gatherer and put into ionization chamber and carry out α and measure.
The present invention is made up of open-air α digital radiation instrument and radon and daughter gatherer two parts.α digital radiation instrument is made of air pulse ionization chamber and its corresponding electronic circuit etc.
Air pulse ionization is working gas with the air, and structure is similar with pulse ionization chamber commonly used, and its shape and size are unrestricted, can decide according to the shape of gatherer.Ionization chamber is insensitive to light, thereby needn't design special light-shading apparatus, makes apparatus structure greatly simple.Ionization chamber has bottom and air intake-exhaust hole, so that put into gatherer or introduction, discharge earth radon gas.
The principle of work of air pulse ionization chamber α digital radiation instrument is: at the ionization chamber shell negative high voltage of supreme kilovolt of hundreds of volts in addition, passive electrode then forms electric field by pull-up resistor ground connection in ionization chamber.When the α particle enters space between ionization chamber and the passive electrode, cause air ionization and the electronics (and negative ion) and the positive ion that produce will move by the α particle under electric field action, thereby on passive electrode, generate electric impulse signal.This signal is sent to pulse-amplitude discriminator through behind high input impedance, low noise prime amplifier and the main amplifier, is noted by impulse meter then.
The container that the radon of indication of the present invention and daughter gatherer thereof are done for the material that the α particle is had adsorbability is called the α cup, and the stein, alpha track cup or other plastic cup that generally adopt plastics to make also claim natural.If raising sensitivity, in cup, added static α card (the dust measuring filter membrane of static electrification high pressure) or activated charcoal, then constitute static α cup or activated charcoal α cup.
When adopting the accumulation of α cup to survey radon, earlier with α cup embedding certain hour on the measuring point in the open air, then with its taking-up, put into ionization chamber and measure, put into the α cup of ionization chamber, in measuring process, because the shielding action of α wall of cup does not influence measurement result even the ionization chamber inwall is subjected to polluting yet.α wall of cup and passive electrode are separated by a distance, and the radon daughter on the wall of cup can not pollute passive electrode.So, when measuring natural or static α cup, can not cause the pollution of ionization chamber.The pollution to ionization chamber in measuring process of activated charcoal α cup is also very little, though the adsorbed radon of activated charcoal will have part to resolve and enter in the air in the ionization chamber, but because ionization chamber shell band negative high voltage, and the decay daughter overwhelming majority of radon is positively charged, they will not pollute so this part radon daughter does not constitute ionization chamber at the inwall of mobile cup under the effect of electric field.What constitute pollution is directly to arrive passive electrode and radon and radon daughter attached thereto, because the passive electrode surface area is very little, this pollution is also not serious.If the passive electrode continuous several times is polluted and the instrument truth of a matter is increased, changing passive electrode can decontaminate.Change electrode and only need half a minute, after the replacing, instrument can commence work without delay.
When doing conventional emanation prospecting with ionization chamber, wall liner last layer film in ionization chamber (as aluminized polyester film or rubber-like acetate fiber transparent film etc.) is to prevent radon and daughter thereof the direct pollution to the ionization chamber inwall.After radon was introduced into ionization chamber, the decay daughter of radon mainly concentrated on the inner lining film the pollution of ionization chamber, and therefore, as long as change this layer film, its pollution can be got rid of substantially.If seriously polluted, can change film and passive electrode simultaneously.Whole process was finished in one minute, and instrument just can restart work, compared Z
nS(A
g) the decontamination processing and lucifuge stand-by period of scintillation chamber shortened more than tens times.
Fig. 1 is cylindric air pulse ionization chamber structural profile synoptic diagram;
Fig. 2 is a α digital radiation instrument circuit schematic diagram;
Fig. 3 is the interface principle figure of instrument and counter.
As shown in Figure 1: ionization chamber is by passive electrode (1), high-field electrode (shell (2) and bottom (3)), insulator (4), protection ring (5) and binding post formations such as (6).Passive electrode (1) links to each other with shell (2) with binding post (6) respectively with screw thread (or alternate manner) with bottom (3), so that dismounting.A, B two hole seats are arranged on the shell (2).The material of making the ionization chamber electrode is the common plastics that the low plating chrome on copper layer of αFu Sheshuiping, brass, stainless steel, aluminium alloy, conductive plastics or its surface are sprayed with conductive layer; It is big that insulator can spray insulation resistance with face, the teflon with hydrophobic nature.
As shown in Figure 2, the ionization chamber shell is negative high voltage in addition, and the size of high pressure is relevant with factors such as ionization chamber sizes.Concrete numerical value is determined by actual measurement high pressure plateau curve.Capacitor C strobes, to get rid of outside electromagnetic interference and from the interference such as ripple of high-voltage power supply.The effect of high-voltage switch gear K is: when laying or taking out the α cup in ionization chamber, disconnect the high pressure on it, to guarantee safety.In fact, ionization chamber is loaded in the cabinet, in its corresponding position, has a wicket on the cabinet so that put into or take out the α cup in ionization chamber.Therefore, K switch can be the toggle switch that is installed on this.When door switch, it can automatically cut off or connect high pressure.Protection ring (5) ground connection is unlikely the useful signal that influences on the passive electrode (1) to guarantee the high pressure electric leakage.
Resistance R among Fig. 2
LAnd the input impedance of field effect transistor (7) pull-up resistor that constitutes passive electrode (1) in parallel.Capacitor C
OBe ionization chamber interelectrode capacity, stray capacitance and prime amplifier input capacitance sum.The input impedance of field effect transistor (7) is much larger than R
LResistance, ionization chamber output pulse former is by R
L, C
OConstitute, get R usually
LC
O=1ms makes ionization chamber be operated in the ion-pulse ionization chamber state.Like this, can overcome the influence of electronegative gas such as oxygen, water vapor.Though the pulse broad of ion-pulse ionization chamber output, the low frequency composition is more, thereby is subject to the interference that shakes in the course of the work, error of omission easily under the high count rate situation.But practice shows: for the former, take suitable earthquake counter measure, can get rid of interference substantially; And the latter is difficult to run in real work, because radon concentration (comprising unusual) great majority are all very weak in the open-air earth, α radiometer digit rate is not high.If it is unusual to run into very strong radon, can changes little ionization chamber with desensitization, or measurement data is leaked the meter correction.
Among Fig. 2, field effect transistor (7) is a prime amplifier, and it and passive electrode (1) directly are coupled.Field effect transistor is selected low noise high input impedance technotron for use, as 3DJ4,3DJ9 etc.Main amplifier IC
1, adopt the single supply low consumed power operational amplifier, as LM324N single supply low power consumpting quadri-operational amplifier.
Ionization chamber passive electrode (1) signal extension line, prime amplifier and main amplifier all should carry out electromagnetic screen.Supply with the high pressure of ionization chamber and the low-tension supply of supply amplifier and all should meet the low noise requirement.
Amplified pulse signal is passed through pulse-amplitude discriminator (8) shaping again, can be sent to counter (band printer or not with printer) or pocket computer (as the PG-1500 pocket computer) is noted by interface circuit (9).
According to the present invention, instrument can directly adopt counter or pocket computer, finishes counting, demonstration or printing, data processing etc. by interface circuit.Fig. 3 is the interface circuit schematic diagram of instrument and counter, and it is revised a little for the design of BL-301 type cassette counter, also is applicable to the counter of other type.The working method that this interface is mended mantissa according to pulse frequency division one constitutes.IC
2For the two binary-coded decimal up counters of MC14518B are made hundred carry pulse frequency dividers, IC
3For MC14017B decimal system counting/pulsqe distributor is made sequential circuit.Interface work is as follows:
One, by zero clearing/start key K
1, finish following operation:
1. make IC
2Zero clearing;
2. make Q
2, Q
2Set, switch (11) conducting, Sheffer stroke gate (12), (14) are closed;
3. make Q
1Reset, zero clearing also starts IC
2;
Two, IC
3The output timing pulse, successively counter is implemented following operation:
1. preset number " 100 ";
2. connect " ten " key once;
Three, the rising edge of time sequential pulse " 5 " makes Q
4Set, IC
3Quit work, and to keep " 5 " be high level, thereby make and door (13) unlatching.Count pulse is introduced by the C end, through entering IC with door (13)
2, the back of its output pulse connected "=" key once along triggering monostable circuit, and counter is that unit carries out accumulated counts with 100 just.
Four, after the timing, timing signal disconnects switch (11) by the input of T end, and Sheffer stroke gate (12) is opened, and makes Q
1Reset, IC
3Start its output timing pulse.Operate "=", "-" and " 1 " three keys successively, thereby make former counting add 100 again, and make counter enter tired 1 duty that subtracts.
Five, the negative edge of time sequential pulse " 9 " makes Q
1, Q
3Set, IC
3Quit work, open with door (14).Clock signal C P enter with door (14) afterwards, enter on the one hand IC
2, drive "=" key on the other hand, make counter do tired 1 the computing that subtracts.This process is up to IC
2Export a pulse, make Q
2Reset, thus close with the door (14) till.Obviously, IC
2Exporting this pulse is by original counting N in it
1(being mantissa) and clock pulse count N
2Addition forms.Promptly
N
1+N
2＝100
So N
1=100-N
2
Wherein, 100 these numbers are added on the former counting in said process four.In the following formula, subtract N
2Subtract 1 this operation and finish by tired; Like this, make IC
2The N of internal memory mantissa
1Add on the former counting.
Interface circuit shown in Figure 3 all adopts the MC14000B series of products, and instrument segment count price is low, the power consumptive province, and kept the various functions of counter itself.
According to the present invention: adopt the wide-mouth plastic cup to make the α cup of radon and daughter gatherer, overlapped, open-air easy to carry.Field test shows: natural embedding time in earth is 6～24 hours; Static α cup is 4～6 hours; Activated charcoal α cup is 6～24 hours or longer, exceeds but should can meet the demands with its sensitivity, and overlong time, humidity is influential to measurement result in the earth.The outdoor operation method that carries out conventional emanation prospecting with air pulse ionization chamber α digital radiation instrument is similar to Other Instruments, the gas sample mode is good with round-robin method in its earth, as abreast inserting in soil at a distance of 10 centimetres two radon gas sampler, and with rubber tube with sampler, double-stranded ball is received on the A, B two holes of ionization chamber shown in Figure 1 in series.Agitate double-stranded ball, gas just flows through ionization chamber circularly in the earth.
The present invention also can be used for
210P
OMethod and soil α actinometry etc.
Claims (10)
1, surveys the radon device in a kind of open-air earth that constitutes by α digital radiation instrument and radon and daughter gatherer thereof, it is characterized in that α digital radiation instrument makes detector with the air pulse ionization chamber, this ionization chamber is working gas with the air, it is characterized in that passive electrode (1) and bottom (3) can dismantle, have A, B two holes on the ionization chamber shell; Radon and daughter gatherer are the common plastics cup.
2, α digital radiation instrument according to claim 1, feature is directly to adopt counter to make the impulse meter of instrument, the mode that the interface of instrument and counter is mended mantissa by pulse frequency division counter one is worked.
3, radon according to claim 1 and daughter gatherer thereof, feature are to load onto static α card (the dust measuring filter membrane of static electrification high pressure) in plastic cup.
4, radon according to claim 1 and daughter gatherer thereof is characterized in that loading onto activated charcoal in plastic cup.
5, use the described survey radon of claim 1 device, the method for getting rid of radon and daughter thereof pollution is to change electrode (1).
6, use the described survey radon of claim 1 device, the method for getting rid of radon and daughter thereof pollution is to add the last layer inner lining film earlier in ionization chamber, after detector is contaminated, changes inner lining film and electrode (1).
7, the described inner lining film of claim 6 is the conductive film of aluminized polyester film one class.
8, the described inner lining film of claim 6 is the insulating material of acetate fiber transparent film one class.
9, the described survey radon of claim 1 device can be used for accumulating the α actinometry of surveying in the radon, and method is to open bottom (3) gatherer is put into ionization chamber to measure.
10, the described survey radon of claim 1 device can be used for the α actinometry in the instantaneous detecting radon, and method is to adopt the round-robin mode that radon gas in the earth is introduced, discharged from the A of ionization chamber, B hole.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN85107800A CN85107800B (en) | 1985-10-23 | 1985-10-23 | Apparatus and operation for detecting rn and its daughter in the soil |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN85107800A CN85107800B (en) | 1985-10-23 | 1985-10-23 | Apparatus and operation for detecting rn and its daughter in the soil |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN85107800A true CN85107800A (en) | 1986-07-23 |
| CN85107800B CN85107800B (en) | 1988-04-20 |
Family
ID=4795785
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN85107800A Expired CN85107800B (en) | 1985-10-23 | 1985-10-23 | Apparatus and operation for detecting rn and its daughter in the soil |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN85107800B (en) |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100371737C (en) * | 2005-12-23 | 2008-02-27 | 成都理工大学应用核技术与自动化工程学院 | Method of detecting radon and its daughter alpha energy spectrum using atmospheric air pulse ionization chamber |
| CN101937107B (en) * | 2009-06-30 | 2012-11-14 | 同方威视技术股份有限公司 | Cabinet and radioactive substance detection device |
| CN103913761A (en) * | 2013-12-12 | 2014-07-09 | 中国人民解放军63653部队 | 222Rn detection efficiency measuring method in activated carbon method |
| CN105209931A (en) * | 2013-03-13 | 2015-12-30 | 马林克罗特有限公司 | Systems and methods for assaying an eluate for technetium and molybdenum content |
| CN105738937A (en) * | 2016-04-29 | 2016-07-06 | 成都理工大学 | Static alpha-cup multifunctional emanometer |
| CN109655872A (en) * | 2019-01-29 | 2019-04-19 | 衡阳师范学院 | Fast measurement of radon device and method |
| CN109655871A (en) * | 2019-01-21 | 2019-04-19 | 衡阳师范学院 | The high detection efficient electrostatic collection formula not influenced by humidity surveys radon method and apparatus |
-
1985
- 1985-10-23 CN CN85107800A patent/CN85107800B/en not_active Expired
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100371737C (en) * | 2005-12-23 | 2008-02-27 | 成都理工大学应用核技术与自动化工程学院 | Method of detecting radon and its daughter alpha energy spectrum using atmospheric air pulse ionization chamber |
| CN101937107B (en) * | 2009-06-30 | 2012-11-14 | 同方威视技术股份有限公司 | Cabinet and radioactive substance detection device |
| CN105209931A (en) * | 2013-03-13 | 2015-12-30 | 马林克罗特有限公司 | Systems and methods for assaying an eluate for technetium and molybdenum content |
| CN103913761A (en) * | 2013-12-12 | 2014-07-09 | 中国人民解放军63653部队 | 222Rn detection efficiency measuring method in activated carbon method |
| CN103913761B (en) * | 2013-12-12 | 2016-05-25 | 中国人民解放军63653部队 | In a kind of active activated carbon method222The detection efficient measuring method of Rn |
| CN105738937A (en) * | 2016-04-29 | 2016-07-06 | 成都理工大学 | Static alpha-cup multifunctional emanometer |
| CN109655871A (en) * | 2019-01-21 | 2019-04-19 | 衡阳师范学院 | The high detection efficient electrostatic collection formula not influenced by humidity surveys radon method and apparatus |
| CN109655872A (en) * | 2019-01-29 | 2019-04-19 | 衡阳师范学院 | Fast measurement of radon device and method |
Also Published As
| Publication number | Publication date |
|---|---|
| CN85107800B (en) | 1988-04-20 |
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