Ionizing radiation refers to carrying enough substances toatomormoleculeInElectronicsBecome a free state, so that these atoms or moleculesionizationRadiation of energy of phenomenon, wavelength less than 100nm, includingcosmic rays、X-rayAnd fromRadioactive materialRadiation.[1-2]
On October 27, 2017,world health organizationThe list of carcinogens published by the International Agency for Research on Cancer is preliminarily collated and referenced. Ionizing radiation (all types) is included in the list of Class I carcinogens.[3]
ionizing radiationMeanswavelengthShortfrequencyHighenergyhigh[1]Ofradial(the dual form of a particle or wave).Ionizing radiation canatom、moleculeOr other binding statesElectronics。Nonionizing radiationNot so.The ionization capacity depends on the energy carried by the ray (particle or wave), not the number of rays.If the radiation does not carry enough ionization energy, a large amount of radiation cannot lead to ionization of the affected object.The full name of ionizing radiation is ionizing radiation, which can directly or indirectly ionize atoms and molecules of substances through interaction with substances.
principle
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Alpha rayIt is a charged particle flow, which is easy to causeionization。Alpha rayWith strong ionization ability, this property can be used.It also brings some damage, and has a great ability to damage tissues in the human body.Due to its high quality and poor penetrationatmosphereIts range is only a few centimeters, which can be blocked by a piece of paper or healthy skin.
Beta rayIt is also a high-speed charged particle, and its ionization power ratioAlpha rayIt is much smaller, but its penetration ability is greater than that of alpha raysGamma rayIt is shorter than the range of beta ray and is easy to bealuminum foil、organic glassAnd other materials.
X-ray and gamma ray are basically the same in nature, which are not chargedwavelengthShortelectromagnetic waveThe penetration of both is very strong, and special attention should be paid to the protection against accidental exposure.
Radiation warning sign
Ionizing radiation exists innatureArtificial radiation has spread in all fields. Those who are specialized in the production, use and research of ionizing radiation are called radiation workers.Occupations related to radiation include: exploration, mining, smelting and finishing of nuclear industrial systems and raw materials, production, use and research of nuclear fuel and reactors;Cultivate new varieties by agricultural irradiation, keep vegetables and fruits fresh, and store grains;X-ray fluoroscopy, photographic diagnosisRadionuclideMeasurement of human organs, radiation treatment of tumors, etc;Various accelerators, ray generators and electron microscopes, electron fast welding machines, color TV picture tubes, high-voltage electron tubes, etc. in the industrial sector.
Natural radiation
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Humans mainly receive fromnatureOf natural radiation.It comes fromsunlight，cosmic raysAnd onCrustExists inradioactivitynuclide。Radon escaping from underground is naturalradiationAnother important source of.From spacecosmic raysIncluding the energetic light quanta,Electronics，Gamma rayAnd X-ray.The main radionuclides found in the earth's crust are uranium, thorium, polonium, and other radioactive substances.They release alpha,β orGamma ray。
Artificial radiation
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radiationIt is widely used in medicine, industry and other fields.Artificial radiation is mainly used for: medical equipment (such as medical and imaging equipment);Research and teaching institutions;Nuclear reactors and their auxiliary facilities, such as uranium mines and nuclear fuel plants.Facilities such as the above must be producedradioactivityWastes, some of which leak a certain amount of radiation into the environment.Radioactive materials are also widely used for people's daily consumption, such asLuminous watch, glazed ceramics, artificial dentures,Smoke detectorEtc.
The related professions also include boiler and pressure vessel nondestructive testing. The commonly used instruction source uses γ source as the signal source, and the radiography machine emits X-rays. The above two methods are commonly used in the nondestructive testing industry.
Hazards and protection
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Ionizing radiation related hazards
In the work exposed to ionizing radiation, if the protective measures are improper, the operating procedures are violated, and the dose of human exposure exceeds a certain limit, harmful effects can occur.Under the action of electric radiation,organismOfReaction degreeIt depends on the type, dose, exposure conditions and body sensitivity of ionizing radiation.Ionizing radiation can cause radiation sickness, which isorganismAlmost all organs and systems have pathological changes, but the changes of nervous system, hematopoietic organs and digestive system are the most obvious.Ionizing radiation pairorganismThe injury of can be divided into acuteRadiation injuryAnd chronicRadiation damage。Receiving a certain dose of radiation in a short time may causeorganismThe acute injuries of the patients usually occur in nuclear accidents and radiotherapy patients.However, a certain dose of scattered irradiation for a long time can cause chronic radiation damage, such as skin damage, hematopoietic disorders, leukopenia, and fertility damage.In addition, excessiveradiationIt can also cause cancer and fetal death andmalformation。
Three principles of protection
(1) Time protection: no matter what kind of radiation, the cumulative dose of human exposure is proportional to the exposure time.ContactradialThe longer the time, the more serious the radiation hazard.Shorten the working time of radioactive work as far as possible to reduce the exposure dose.
(2) Distance protection:Radiation dose rateIt is inversely proportional to the square of the distance from the radioactive source. The greater the distance from the radioactive source, the smaller the dose rate there is.So try to keep away from radioactive sources during work.To achieve the purpose of protection.
(3) Shielding protection: it is to set a protective barrier between people and radioactive sources.Because the ray passes throughAtomic numberLarge substances will be absorbed a lot, so that the radiation dose reaching the human body will be reduced.Common shielding materials include lead, reinforced cementLead glassEtc.
The biggest concern about ionizing radiation is that it may cause fatal diseases to the exposed personnel and may appear in future generationsGenetic defect。The possibility of such effects depends on the amount of radiation exposure to personnel, regardless of whether the exposure is fromNatural radiation sourceIt is also an artificial radiation source.With more and more understanding of the effects of ionizing radiation in recent decades, people have developed a complete set of radiation protection methods to protect human beings from various radiation sources.Even so, public concerns remain.[1]
Radiation is only one of the many causes of cancer, a dreaded disease.Because radiation is invisible and untouchable, it makes this hazard that cannot be detected by the naked eye more frightening.When people think of the accidents that have occurred in nuclear power plants and other facilities, the effects that are still happening in some cases today, and the tendency to associate any form of radiation with "nuclear", including nuclear weapons, they become more worried.[1]
Another reason why people are generally worried about radiation may be related to the lack of reliable and easily available information and the resulting misunderstanding.[1]
