October 23, 2014 at 09:37A little bit about radiation
I’m already used to the fact that for most people radiation is an area of mythology, not science. But then I came across this entry , in which a professional type already explains the insane danger of Soviet smoke detectors. After that, I decided that it’s worth doing enlightenment.
What is the answer to the question “is radiation harmful?” The same as for the questions “is the temperature harmful?” Or “is the light harmful?”. It is not the phenomenon itself that is harmful, but the departure of its numerical parameters beyond the limits optimal for life. Numerous animal experiments have shown a slight increase in average life expectancy, increased immunity, etc. with some additional, relatively natural, exposure. They also showed a decrease in all these parameters with a further increase in the dose of radiation. Of course, there was no universal dose for all types of animals, giving the optimal result, for all it is different. No one knows what level of radiation would be ideal for a person, because for this, it would have been necessary to put controlled experiments on tens of thousands of people.
But another thing is known: a person has different sensitivity to different factors. For example, a person feels well at a temperature of 300 K (27 ° C), but if you change it by only 10%, to -3 ° C or 57 ° C, then without trained equipment (appropriate clothing) only a few trained people will be able to to survive. If you change it by 20%, to -33 ° C or 87 ° C, then not a single person will survive for long without protection. But a smooth change in illumination by 10-20 times a person does not notice at all. The difference between bright artificial lighting and ambient light on a sunny day is about 1000 times ... Of course, in complete darkness a person can survive, but with great difficulty, and too bright lighting will already cause a problem with temperature. But in general, the allowable range of changes is many thousands of times.
What is the sensitivity of a person to radiation exposure? Low enough. The natural level of radiation in different parts of the world varies extremely significantly. If on average throughout the Earth a person receives a dose of 2.4 mSv per year, then in some places only 1 mSv, and in others 10, or even 15-20 odd. But no reliable data showing that this scatter affects health was found. For example, residents of Switzerland, which is famous for the high life expectancy of its citizens, are exposed to high doses of radiation. Cosmonauts receive even more radiation doses - about 0.5 mSv per ... day! Those. per month they receive as much as the inhabitants of the most radioactive corners of the planet in a year.
Of course, this is not a reason to go on an excursion under the sarcophagus of the fourth Chernobyl power unit. There, in a minute you will receive a dose of more than a month on the ISS, and such exposure absolutely reliably has an extremely adverse effect on life expectancy. But to be afraid of everything and everything is also not worth it.
In the last section, I used the mSv unit everywhere. This is a millisievert. Let's see what it is, and what kind of units there are in general.
To begin with, on hearing - x-rays (P). In x-rays, only x-ray and gamma radiation are measured. This unit measures the so-called exposure dose, i.e. how many ions give rise to radiation in dry air. It is extremely convenient when measuring with an ionization chamber, because This type of sensor measures precisely the number of ions (more precisely, their total charge). The dose in x-rays can be obtained directly, while all other doses are measured indirectly, leaving room for measurement errors. But, on the other hand, this dose does not directly indicate what harm radiation does to a person, and it is impossible to use it for beta and alpha radiation with other neutrons, it is not defined for them.
The next unit is glad. Rad is a unit of absorbed dose of any radiation. Those. how much energy of ionizing radiation is absorbed by a unit mass of a substance. Rad is equal to 100 erg per 1 gram or 0.01 Joules per 1 kg. Kerma is also measured in radas. Kerma is how much kinetic energy the charged particles of a substance receive when this substance absorbs ionizing radiation that does not carry a charge (gamma, neutrons). In most cases, the absorbed dose and kerma are very exact, so do not bother yourself with this. If the air absorbs 0.88 rad of gamma radiation, then ions of 1 R will appear in it. We can arbitrarily say that 1 P = 0.88 rad, and 1 rad of gamma radiation is 1.14 R. However, because . all the same, the air does not exactly correspond to human tissues, and the tissues are different, plus the dosimeter error is rarely less than 20%, usually consider 1 P = 1 rad. The disadvantage is glad, or rather - the absorbed dose, is that it does not take into account the significantly different effects of various types of radiation on the body.
The next unit is the biological equivalent of rad (rem). Rem is a unit of equivalent dose. Those. it takes into account that fast neutrons at the same energy will cause 10, and alpha particles - 20 times more harm to the body than gamma or beta radiation. Corresponding coefficients are (or can be obtained) for absolutely any type of ionizing radiation. In rems, the effective dose is measured, which takes into account the different sensitivity of different organs. If a person is irradiated completely evenly, then the equivalent and effective dose are the same, but if some parts of the body are irradiated more and some are weaker, there may be noticeable differences. So, for example, the hands withstand very large doses, but the spinal cord is very sensitive to radiation. In rems, the ambivalent dose equivalent is also measured - such a "spherical dose in a vacuum." No kidding, it is defined for a 30 cm ball of strictly standardized composition, it is used for all kinds of tests, modeling, etc.
Next we have gray (Gr). Gray is an analog of glad in the SI system. 1 Gy = 1 J / kg = 100 rad.
And finally, sievert (Sv). This is an analogue of rem in SI. 1 Sv = 100 rem. Accordingly, the mSv that I used in the first section is 0.001 Sv or 0.1 rem.
In addition to the dose, there is also the activity of a radioactive substance. Those. how many decays in it occur in a given time. Activity is measured either in curie (Ki) or becquerel (Bq). Curie - the activity of one gram of radium-226, a very large value. Becquerel - one decay per second, a very small value. 1 Ki = 37 GBq.
To make it easier to navigate, I will give some numbers:
- the level of gamma radiation in my room is about 7 μR / h, 0.07 μGy / h and 0.07 μSv / h (exposure, absorbed and equivalent dose rates, respectively). The level of gamma radiation on the granite-trimmed platforms of the Moscow Metro is about twice as high (plus the dose of alpha radiation to the lungs from elevated levels of radon);
- a single dose at which radiation sickness can begin - 100 R, 1 Gy and 1 Sv;
- the activity of natural radioactive potassium-40 in a banana is approximately 20 Bq, in a kilogram of bananas - 130 Bq.
In principle, there are a huge number of different instruments and methods for measuring radiation, but I will only talk about what, in principle, a person who does not work in the appropriate areas may encounter.
In stores you can find "indicators of radioactivity", "dosimeters" and "dosimeters-radiometers".
The first are devices that do not pass any significant tests and generally do not claim to be accurate. Almost always they are made on the basis of a Geiger type SBM-20 counter. Less commonly, it is based on the miniature SBM-21 or on the basis of alpha-sensitive meters, for example Beta-1 or Beta-2. Many believe that such devices can underestimate the readings. Some "professionals" claim that at low gamma radiation energy, at a level of 30-100 keV, the devices on SBM-20 and SBM-21 are underestimated at times, but are not recorded at all below. My experience shows that everything is exactly the opposite: at low gamma-ray energy (experiments were set at 59 keV) they overestimate their readings by several times. Of course, they will not record gamma radiation of very low energy, but it does not pose a great danger, because absorbed in the skin.
An honest manufacturer usually calls a dosimeter a device whose measurement accuracy was given no attention. Most often they are also made on the basis of SBM-20, but it is already closed with a special removable filter that attenuates low-energy gamma radiation and completely absorbs beta radiation. This allows you to accurately measure the level of gamma radiation in a wide range of energies. Also, these devices are usually able to integrate readings over a long time, showing not only the dose rate, but also the dose itself. Devices better contain Beta-1, Beta-2 or other sensors with a mica window for low-energy beta radiation and alpha radiation, also equipped with filters. Quite expensive devices can use semiconductor or scintillation sensors, which have great sensitivity to gamma radiation and do not just capture particles, but measure their energy. This allows you to measure the dose as accurately as possible, and some models even know how to determine the isotopes that cause radiation. However, semiconductors and scintillators can play a trick: their sensitivity is very dependent on energy, so measuring it is not just possible, but necessary. And you need to qualitatively take into account the dependence of sensitivity on energy. If such a sensor was inserted into the device only for a loud inscription “scintillator”, then the accuracy of measurements may be worse than with cheap indicators of radioactivity. but it is necessary. And you need to qualitatively take into account the dependence of sensitivity on energy. If such a sensor was inserted into the device only for a loud inscription “scintillator”, then the accuracy of measurements may be worse than with cheap indicators of radioactivity. but it is necessary. And you need to qualitatively take into account the dependence of sensitivity on energy. If such a sensor was inserted into the device only for a loud inscription “scintillator”, then the accuracy of measurements may be worse than with cheap indicators of radioactivity.
A dosimeter-radiometer is a device that, in addition to a dose of gamma radiation, also measures the flow of beta particles (with the corresponding sensors - and alpha). The two previous points also record beta radiation (dosimeters - with the filter removed), but they continue to recalculate readings in x-rays or sievert, as if it were gamma radiation. The result is absolutely wrong: if for gamma radiation the probability of fixing a particle by a Geiger counter is directly proportional to its energy in a rather wide range (somewhere from 0.3 to 1.5 MeV), and this range is expanded by filters down to about 0, 03-0.05 MeV, there is nothing like that for beta radiation. As a first approximation, above a certain energy limit, the sensor captures almost all beta particles, and below it, not a single one. Similarly with alpha radiation (if the counter fixes it in principle). The radiometer can be “told” that you are now measuring beta radiation, and then it will recalculate the readings in the number of particles per square centimeter of the sensor’s cross-sectional area per unit time. First, you measure with a filter to find out the gamma background, then without it, you subtract the first from the second - and here is the stream of beta particles. For alpha, everything is the same, only a second filter is added there, which delays it, but passes beta particles. Sometimes it is built-in, sometimes you yourself need to take the helper, such as a sheet of paper. only there a second filter is still added, which delays it, but passes beta particles. Sometimes it is built-in, sometimes you yourself need to take the helper, such as a sheet of paper. only there a second filter is still added, which delays it, but passes beta particles. Sometimes it is built-in, sometimes you yourself need to take the helper, such as a sheet of paper.
There are also software dosimeters for smartphones that use a camera closed with an opaque material as an ersatz detector. They really work, but in my experience it’s not necessary to expect accuracy from them, they can be wrong at times in any direction.
It is also worth noting that at low radiation levels the readings of all instruments are not very accurate: they record only about a dozen particles per measurement cycle, so that the statistical error becomes comparable with the measured value. If now the device shows 0.07 μSv / h, and after a minute - 0.14 μSv / h, this does not mean at all that the level of radiation has doubled. Most likely, he remained at 0.10 μSv / h.
Another remark about the actual measurements: they need to be carried out so that the sensor of the device can be considered point. Those. either the radiation source, or the distance from it to the sensor should be several times greater than the sensor itself. If you poke a drop of radium paint on the tip of the toggle switch in the center of some Beta-2, then at different points of the sensor the radiation level differs by several orders of magnitude. What a sensor measures in such conditions is “only God knows”. Measurements “on the surface” are acceptable either for large sources (contaminated soil, for example), or when we are not trying to measure it, but only with maximum sensitivity to record the fact of the presence of radiation.
Radioactivity indicator at the site of radioactive contamination
Professional scintillator dosimeter at the site of radioactive contamination (radiation level - figures below)
Software dosimeter. In this particular case, 3-4 times underestimates
What radiation sources can be found in everyday life? Variety.
For example, everything that contains a lot of potassium, potash fertilizers, dietary salt with potassium supplements, etc., is radioactive due to the content of natural potassium-40. A person, by the way, is also radioactive, because potassium is an integral element of the body.
If we take the sources more seriously, these are toriated welding electrodes (for example, WT-20 brands), some old lenses with thorium oxide added to the glass, some old watches and other devices with a radium scale backlight (now the backlight no longer works from due to the burning out of the phosphor, radium persists for thousands of years), ionization smoke detectors on americium-241, old ionization smoke detectors on plutonium-239 (weapons-grade, by the way), etc.
As long as all this remains safe and sound, it, as a rule, is not dangerous. Problems can only occur with the destruction of devices, as in this case, particles of alpha-active materials can get into the lungs and create a strong local exposure there. The risk of cancer is greatly increased. By the way, lung cancer in smokers is to a considerable degree caused by the same thing: tobacco contains alpha-active polonium-210, the same one that Litvinenko was poisoned with.
Also, it’s completely legal to use all these things without special permissions: only once I came across a pressure gauge whose radiation level exceeded the permissible limits for unlicensed use (1 μSv / h at a distance of 10 cm from the surface), but it was from the MIG-21 fighter. However, the laws in our country are not very well implemented ... “Specialists” can easily say that everything that has a radiation level of more than 30 μR / h directly on the surface must be removed. But judges do not really understand such subtleties as radiation safety standards ... There is at least one precedent when a person was taken away by a court from a person and they were not put in prison just because he did not know about his radioactivity. By all official standards, this lens could be used.
The real danger is posed only by industrial radiation sources, operating x-ray machines and uncontrolled emergency emissions. Fortunately, facing them is not so simple for a simple person. Although the history of precedents knows ...
Plutonium source from the RID-1 smoke sensor. The very one about which horror stories are told in the article that provoked the writing of this text. While intact, does not pose a significant danger.
Relatively safe instrument with radium illumination
A large accumulation of relatively safe instruments may no longer be so safe
A rare example of a device with radium illumination that is more than ten times beyond the permissible limits An
industrial source that can be a real danger
Contaminated area
Uncontrolled emergency release result half a century ago
Nuclear reactor core
Radiation damage
What is the answer to the question “is radiation harmful?” The same as for the questions “is the temperature harmful?” Or “is the light harmful?”. It is not the phenomenon itself that is harmful, but the departure of its numerical parameters beyond the limits optimal for life. Numerous animal experiments have shown a slight increase in average life expectancy, increased immunity, etc. with some additional, relatively natural, exposure. They also showed a decrease in all these parameters with a further increase in the dose of radiation. Of course, there was no universal dose for all types of animals, giving the optimal result, for all it is different. No one knows what level of radiation would be ideal for a person, because for this, it would have been necessary to put controlled experiments on tens of thousands of people.
But another thing is known: a person has different sensitivity to different factors. For example, a person feels well at a temperature of 300 K (27 ° C), but if you change it by only 10%, to -3 ° C or 57 ° C, then without trained equipment (appropriate clothing) only a few trained people will be able to to survive. If you change it by 20%, to -33 ° C or 87 ° C, then not a single person will survive for long without protection. But a smooth change in illumination by 10-20 times a person does not notice at all. The difference between bright artificial lighting and ambient light on a sunny day is about 1000 times ... Of course, in complete darkness a person can survive, but with great difficulty, and too bright lighting will already cause a problem with temperature. But in general, the allowable range of changes is many thousands of times.
What is the sensitivity of a person to radiation exposure? Low enough. The natural level of radiation in different parts of the world varies extremely significantly. If on average throughout the Earth a person receives a dose of 2.4 mSv per year, then in some places only 1 mSv, and in others 10, or even 15-20 odd. But no reliable data showing that this scatter affects health was found. For example, residents of Switzerland, which is famous for the high life expectancy of its citizens, are exposed to high doses of radiation. Cosmonauts receive even more radiation doses - about 0.5 mSv per ... day! Those. per month they receive as much as the inhabitants of the most radioactive corners of the planet in a year.
Of course, this is not a reason to go on an excursion under the sarcophagus of the fourth Chernobyl power unit. There, in a minute you will receive a dose of more than a month on the ISS, and such exposure absolutely reliably has an extremely adverse effect on life expectancy. But to be afraid of everything and everything is also not worth it.
Radiation units
In the last section, I used the mSv unit everywhere. This is a millisievert. Let's see what it is, and what kind of units there are in general.
To begin with, on hearing - x-rays (P). In x-rays, only x-ray and gamma radiation are measured. This unit measures the so-called exposure dose, i.e. how many ions give rise to radiation in dry air. It is extremely convenient when measuring with an ionization chamber, because This type of sensor measures precisely the number of ions (more precisely, their total charge). The dose in x-rays can be obtained directly, while all other doses are measured indirectly, leaving room for measurement errors. But, on the other hand, this dose does not directly indicate what harm radiation does to a person, and it is impossible to use it for beta and alpha radiation with other neutrons, it is not defined for them.
The next unit is glad. Rad is a unit of absorbed dose of any radiation. Those. how much energy of ionizing radiation is absorbed by a unit mass of a substance. Rad is equal to 100 erg per 1 gram or 0.01 Joules per 1 kg. Kerma is also measured in radas. Kerma is how much kinetic energy the charged particles of a substance receive when this substance absorbs ionizing radiation that does not carry a charge (gamma, neutrons). In most cases, the absorbed dose and kerma are very exact, so do not bother yourself with this. If the air absorbs 0.88 rad of gamma radiation, then ions of 1 R will appear in it. We can arbitrarily say that 1 P = 0.88 rad, and 1 rad of gamma radiation is 1.14 R. However, because . all the same, the air does not exactly correspond to human tissues, and the tissues are different, plus the dosimeter error is rarely less than 20%, usually consider 1 P = 1 rad. The disadvantage is glad, or rather - the absorbed dose, is that it does not take into account the significantly different effects of various types of radiation on the body.
The next unit is the biological equivalent of rad (rem). Rem is a unit of equivalent dose. Those. it takes into account that fast neutrons at the same energy will cause 10, and alpha particles - 20 times more harm to the body than gamma or beta radiation. Corresponding coefficients are (or can be obtained) for absolutely any type of ionizing radiation. In rems, the effective dose is measured, which takes into account the different sensitivity of different organs. If a person is irradiated completely evenly, then the equivalent and effective dose are the same, but if some parts of the body are irradiated more and some are weaker, there may be noticeable differences. So, for example, the hands withstand very large doses, but the spinal cord is very sensitive to radiation. In rems, the ambivalent dose equivalent is also measured - such a "spherical dose in a vacuum." No kidding, it is defined for a 30 cm ball of strictly standardized composition, it is used for all kinds of tests, modeling, etc.
Next we have gray (Gr). Gray is an analog of glad in the SI system. 1 Gy = 1 J / kg = 100 rad.
And finally, sievert (Sv). This is an analogue of rem in SI. 1 Sv = 100 rem. Accordingly, the mSv that I used in the first section is 0.001 Sv or 0.1 rem.
In addition to the dose, there is also the activity of a radioactive substance. Those. how many decays in it occur in a given time. Activity is measured either in curie (Ki) or becquerel (Bq). Curie - the activity of one gram of radium-226, a very large value. Becquerel - one decay per second, a very small value. 1 Ki = 37 GBq.
To make it easier to navigate, I will give some numbers:
- the level of gamma radiation in my room is about 7 μR / h, 0.07 μGy / h and 0.07 μSv / h (exposure, absorbed and equivalent dose rates, respectively). The level of gamma radiation on the granite-trimmed platforms of the Moscow Metro is about twice as high (plus the dose of alpha radiation to the lungs from elevated levels of radon);
- a single dose at which radiation sickness can begin - 100 R, 1 Gy and 1 Sv;
- the activity of natural radioactive potassium-40 in a banana is approximately 20 Bq, in a kilogram of bananas - 130 Bq.
Radiation Measuring Instruments
In principle, there are a huge number of different instruments and methods for measuring radiation, but I will only talk about what, in principle, a person who does not work in the appropriate areas may encounter.
In stores you can find "indicators of radioactivity", "dosimeters" and "dosimeters-radiometers".
The first are devices that do not pass any significant tests and generally do not claim to be accurate. Almost always they are made on the basis of a Geiger type SBM-20 counter. Less commonly, it is based on the miniature SBM-21 or on the basis of alpha-sensitive meters, for example Beta-1 or Beta-2. Many believe that such devices can underestimate the readings. Some "professionals" claim that at low gamma radiation energy, at a level of 30-100 keV, the devices on SBM-20 and SBM-21 are underestimated at times, but are not recorded at all below. My experience shows that everything is exactly the opposite: at low gamma-ray energy (experiments were set at 59 keV) they overestimate their readings by several times. Of course, they will not record gamma radiation of very low energy, but it does not pose a great danger, because absorbed in the skin.
An honest manufacturer usually calls a dosimeter a device whose measurement accuracy was given no attention. Most often they are also made on the basis of SBM-20, but it is already closed with a special removable filter that attenuates low-energy gamma radiation and completely absorbs beta radiation. This allows you to accurately measure the level of gamma radiation in a wide range of energies. Also, these devices are usually able to integrate readings over a long time, showing not only the dose rate, but also the dose itself. Devices better contain Beta-1, Beta-2 or other sensors with a mica window for low-energy beta radiation and alpha radiation, also equipped with filters. Quite expensive devices can use semiconductor or scintillation sensors, which have great sensitivity to gamma radiation and do not just capture particles, but measure their energy. This allows you to measure the dose as accurately as possible, and some models even know how to determine the isotopes that cause radiation. However, semiconductors and scintillators can play a trick: their sensitivity is very dependent on energy, so measuring it is not just possible, but necessary. And you need to qualitatively take into account the dependence of sensitivity on energy. If such a sensor was inserted into the device only for a loud inscription “scintillator”, then the accuracy of measurements may be worse than with cheap indicators of radioactivity. but it is necessary. And you need to qualitatively take into account the dependence of sensitivity on energy. If such a sensor was inserted into the device only for a loud inscription “scintillator”, then the accuracy of measurements may be worse than with cheap indicators of radioactivity. but it is necessary. And you need to qualitatively take into account the dependence of sensitivity on energy. If such a sensor was inserted into the device only for a loud inscription “scintillator”, then the accuracy of measurements may be worse than with cheap indicators of radioactivity.
A dosimeter-radiometer is a device that, in addition to a dose of gamma radiation, also measures the flow of beta particles (with the corresponding sensors - and alpha). The two previous points also record beta radiation (dosimeters - with the filter removed), but they continue to recalculate readings in x-rays or sievert, as if it were gamma radiation. The result is absolutely wrong: if for gamma radiation the probability of fixing a particle by a Geiger counter is directly proportional to its energy in a rather wide range (somewhere from 0.3 to 1.5 MeV), and this range is expanded by filters down to about 0, 03-0.05 MeV, there is nothing like that for beta radiation. As a first approximation, above a certain energy limit, the sensor captures almost all beta particles, and below it, not a single one. Similarly with alpha radiation (if the counter fixes it in principle). The radiometer can be “told” that you are now measuring beta radiation, and then it will recalculate the readings in the number of particles per square centimeter of the sensor’s cross-sectional area per unit time. First, you measure with a filter to find out the gamma background, then without it, you subtract the first from the second - and here is the stream of beta particles. For alpha, everything is the same, only a second filter is added there, which delays it, but passes beta particles. Sometimes it is built-in, sometimes you yourself need to take the helper, such as a sheet of paper. only there a second filter is still added, which delays it, but passes beta particles. Sometimes it is built-in, sometimes you yourself need to take the helper, such as a sheet of paper. only there a second filter is still added, which delays it, but passes beta particles. Sometimes it is built-in, sometimes you yourself need to take the helper, such as a sheet of paper.
There are also software dosimeters for smartphones that use a camera closed with an opaque material as an ersatz detector. They really work, but in my experience it’s not necessary to expect accuracy from them, they can be wrong at times in any direction.
It is also worth noting that at low radiation levels the readings of all instruments are not very accurate: they record only about a dozen particles per measurement cycle, so that the statistical error becomes comparable with the measured value. If now the device shows 0.07 μSv / h, and after a minute - 0.14 μSv / h, this does not mean at all that the level of radiation has doubled. Most likely, he remained at 0.10 μSv / h.
Another remark about the actual measurements: they need to be carried out so that the sensor of the device can be considered point. Those. either the radiation source, or the distance from it to the sensor should be several times greater than the sensor itself. If you poke a drop of radium paint on the tip of the toggle switch in the center of some Beta-2, then at different points of the sensor the radiation level differs by several orders of magnitude. What a sensor measures in such conditions is “only God knows”. Measurements “on the surface” are acceptable either for large sources (contaminated soil, for example), or when we are not trying to measure it, but only with maximum sensitivity to record the fact of the presence of radiation.
Radioactivity indicator at the site of radioactive contamination
Professional scintillator dosimeter at the site of radioactive contamination (radiation level - figures below)
Software dosimeter. In this particular case, 3-4 times underestimates
Radiation in the home
What radiation sources can be found in everyday life? Variety.
For example, everything that contains a lot of potassium, potash fertilizers, dietary salt with potassium supplements, etc., is radioactive due to the content of natural potassium-40. A person, by the way, is also radioactive, because potassium is an integral element of the body.
If we take the sources more seriously, these are toriated welding electrodes (for example, WT-20 brands), some old lenses with thorium oxide added to the glass, some old watches and other devices with a radium scale backlight (now the backlight no longer works from due to the burning out of the phosphor, radium persists for thousands of years), ionization smoke detectors on americium-241, old ionization smoke detectors on plutonium-239 (weapons-grade, by the way), etc.
As long as all this remains safe and sound, it, as a rule, is not dangerous. Problems can only occur with the destruction of devices, as in this case, particles of alpha-active materials can get into the lungs and create a strong local exposure there. The risk of cancer is greatly increased. By the way, lung cancer in smokers is to a considerable degree caused by the same thing: tobacco contains alpha-active polonium-210, the same one that Litvinenko was poisoned with.
Also, it’s completely legal to use all these things without special permissions: only once I came across a pressure gauge whose radiation level exceeded the permissible limits for unlicensed use (1 μSv / h at a distance of 10 cm from the surface), but it was from the MIG-21 fighter. However, the laws in our country are not very well implemented ... “Specialists” can easily say that everything that has a radiation level of more than 30 μR / h directly on the surface must be removed. But judges do not really understand such subtleties as radiation safety standards ... There is at least one precedent when a person was taken away by a court from a person and they were not put in prison just because he did not know about his radioactivity. By all official standards, this lens could be used.
The real danger is posed only by industrial radiation sources, operating x-ray machines and uncontrolled emergency emissions. Fortunately, facing them is not so simple for a simple person. Although the history of precedents knows ...
Plutonium source from the RID-1 smoke sensor. The very one about which horror stories are told in the article that provoked the writing of this text. While intact, does not pose a significant danger.
Relatively safe instrument with radium illumination
A large accumulation of relatively safe instruments may no longer be so safe
A rare example of a device with radium illumination that is more than ten times beyond the permissible limits An
industrial source that can be a real danger
Contaminated area
Uncontrolled emergency release result half a century ago
Nuclear reactor core
