Gamma ray, that is, gamma ray, is a spectrum with the shortest wavelength and the highest frequency in the electromagnetic spectrum. Humans have long known and can make them. However, this question is a bit strange and unclear, such as: What is mastery?
Can it be handled or used? It depends on how to say it. Let's explain this problem from some common sense of gamma rays. If friends can read this article carefully, they will find this question a bit strange as I do, and they will also know something about gamma rays.
What we humans see and feel now, even everything involved in eating and drinking Lazar, depends on electromagnetic waves. Why do you say that? Because electromagnetic waves are everywhere in our world, as long as it is above absolute zero, any object will have electromagnetic radiation. The so-called electromagnetic radiation is transmitted by electromagnetic waves.
Electromagnetic waves are transmitted by photons, so they can also be called light waves. But this light wave is divided into visible light and invisible light. In daily life, light wave generally refers to the visible part of the electromagnetic spectrum, and visible light is only a short section sandwiched between the electromagnetic spectrum. The longest wave band of electromagnetic waves is several kilometers or even longer; The shortest is only below 1 Amy, and the shortest is gamma ray.
Electromagnetic waves have wavelength and frequency, and the wavelength is inversely proportional to the frequency, that is, the longer the wavelength, the lower the frequency and the smaller the energy; On the contrary, the greater the energy. The relationship between the wavelength and frequency of electromagnetic waves is: c = λ f where c is the speed of light, λ is the wavelength and f is the frequency. The longest wavelength of electromagnetic wave is radio wave (including long wave, medium wave, short wave and microwave), followed by infrared ray, visible light, ultraviolet ray, X ray and γ ray from long to short.
The wavelength of radio waves ranges from kilometers to millimeters, the wavelength of long-wave radio can reach several kilometers, and the shortest microwave wavelength is only 0. 1 millimeter; The wavelength of visible light is about 760nm to 380nm, which means nanometer, 1 mm = 1000μm (micron), 1μm= 1000nm,1nm =/kloc-0-9.
The wavelengths of ultraviolet rays, X rays and gamma rays (gamma rays) behind visible light are shorter than each other. Gamma rays are high-energy rays with the shortest wavelength among electromagnetic waves, and the wavelength is only below 0. 1nm.
All substances in this world are vibrating, so they all have frequencies. Frequency is the number of times that an object vibrates per second, and the frequency of electromagnetic waves is the number of times that electromagnetic waves vibrate per second, expressed in Hz. The frequency of radio waves is 1000Hz or lower, between 10 9Hz; The frequency range of visible light is 3.9 * 10 14 to 7.7 *10/4 Hz; The lowest range of gamma ray frequency is 10 12hz, and the highest range is over10 30hz.
The size of COVID-19 is about 100nm, and the longest gamma ray band is only 0. 1nm. When you think about it, people are at a loss about COVID-19, not to mention gamma rays, which are 1000 times smaller than COVID-19 and have a frequency of over one trillion times per second. How big is this energy? Once swept by gamma rays, there is no reason not to penetrate it.
So gamma rays are the most powerful "light" in the universe, but this kind of light is invisible, but it will kill people.
Because of its short wavelength and extremely high energy, gamma rays can penetrate the body of any living thing. Biological organism is composed of cells, and the core of each cell is genetic material DNA. For example, the human body consists of 40-60 trillion cells, large and small. The largest cell is an egg, and the mature egg is 200μm (micron). The smallest cell is platelet, which is only about 2μm in diameter.
When the human body is irradiated by gamma rays, the gamma rays will enter human cells and ionize them. Ionized ions will attack complex organic molecules in cells and destroy cell tissues. The most important core genetic material in cells is DNA, which is a macromolecule with double helix structure. It occupies the core of the cell and dominates the life and death and inheritance of the cell.
This DNA double helix is about two meters long. If all the DNA in 1 human cell is opened and connected, it is said that it can travel from the earth to the sun more than 300 times. However, the diameter of DNA helix is only 2nm, and gamma rays will interrupt and destroy its structure. Therefore, when organisms are irradiated by gamma rays, the molecular bonds of DNA will break, thus making it impossible for organisms to survive.
When the amount of radiation is large, organisms will die instantly. Even if the amount of radiation is small, the molecular bonds of DNA will be seriously damaged, and it will die slowly. That kind of death is watching your body die inch by inch, which is extremely horrible. In the notorious explosion accident of Chernobyl nuclear power plant, many residents and firefighters suffered from this hellish torture and died.
Radioactive nuclei will produce a new nucleus after alpha decay and beta decay. This new nucleus is at a high energy level and must transition to a low energy level. During the transition, gamma photons, that is, gamma rays, are emitted. Both nuclear fusion and nuclear fission produce gamma rays, so the universe is full of gamma ray radiation.
The nuclear fusion of the sun continues in the core with a volume radius of 1/4. The main process is the chain reaction between nuclei, from deuterium to helium -3 and finally to helium -4. The result is that four atoms fuse into a helium -4 nucleus, releasing gamma photons, neutrinos and positrons in the process. Neutrinos quickly escape from the surface of the sun to space because of their strong penetrating power, but gamma rays with huge energy are not easy to escape.
This involves the theory that photons walk in the sun. The characteristic of photon propagation is that the vacuum is the fastest, reaching 300 thousand kilometers per second, but it bumps in the medium. The interior of the sun is full of protons, and photons will encounter protons every step of the way, constantly colliding and exchanging. So these photons have to penetrate the sun with a radius of 700,000 kilometers and collide with protons 10 26 times. Every exchange will be consumed and attenuated. After hundreds of thousands or even millions of years, the photons reaching the surface of the sun are mainly visible light.
So don't be surprised, the sunlight that shines on us is actually photons born hundreds of thousands or even millions of years ago.
According to scientific analysis, sunlight contains the whole electromagnetic wave band, but more than 99.9% of the energy is concentrated in the wavelength range of 200~ 10000nm, and the maximum radiation energy is at 480nm, which is the range of visible blue light. So the sky we see is blue, and so is the sea.
The 200nm band belongs to the category of ultraviolet rays. Too much ultraviolet rays are harmful to the human body, but most of the ultraviolet rays are absorbed or reflected by the ozone layer when passing through the atmosphere, and very few of them reach the surface. But there is still one thing, so when the sun is strong, the skin will hurt for a long time.
The stars in the universe are all in nuclear fusion, constantly radiating gamma rays; There are also supernova explosions, collisions between dense objects such as neutron stars, which will produce more gamma rays, even gamma ray bursts, so there are many gamma rays in space. However, these gamma rays are blocked by the atmosphere and rarely reach the surface.
If you are active at high altitude or outside the atmosphere, you will be easily influenced by gamma rays and other cosmic rays, so astronauts should take preventive measures. However, it is difficult to block gamma rays. Despite the good protection of spaceships and spacesuits, astronauts living in space or other planets receive much more radiation than the surface of the earth.
Gamma rays have strong penetrating power, which can't be shielded by ordinary buildings. Only special high-density materials, such as lead plate, have certain effects, and the thickness of lead plate needs to be increased according to the intensity of gamma rays.
Heavy nuclear fission process will be deformed. For example, after a neutron is absorbed by the uranium -235 nucleus, it will form an excited uranium -236 nucleus, which will then deform and finally break and fly away in the opposite direction. Classical Coulomb energy will be converted into kinetic energy of two fragments, but soon the broken fragments will shrink into spheres, and the deformation kinetic energy will be converted into internal excitation energy, and some neutrons and gamma rays will be emitted to balance the de-excitation energy.
There are many decay processes of radioactive elements, such as cobalt -60, which will release high-speed electrons with energy as high as 3 15keV through beta decay, decay into nickel 60, and release two gamma rays at the same time. If these gamma rays are not well controlled, they will do harm to human beings.
Such as atomic bomb explosion or nuclear power plant leakage, the explosion of Chernobyl nuclear power plant in the former Soviet Union caused serious radioactive pollution, threatening the health of millions of people, and more than 7,000 people died directly from radiation.
Human civilization is advanced through continuous understanding of the laws of nature. Gamma ray itself is a natural phenomenon, which is a kind of energy released by elements in the process of polymerization or division. If people know the inherent properties of gamma rays, they can handle and use them.
Any science can be used to benefit mankind, and it can also be used to harm people, so can gamma rays, which can kill people and benefit mankind. I have said a lot about the harm of gamma rays, and now I will talk about the benefit of mankind.
At present, the relatively common gamma rays serving human beings are used for industrial flaw detection and medical care. Industrial flaw detection mainly uses the penetration of gamma rays to check whether there is any problem in the internal structure of industrial products, such as detecting the weld of steel plates. The weld seam of 30 mm thick steel plate can be inspected by X-ray, but beyond this thickness, there is nothing we can do, and gamma rays with stronger penetration will show their talents.
Gamma rays can detect steel plates with a thickness of 300 mm by sticking a photosensitive film on the back of the inspected object and irradiating the inspected object with gamma rays. When gamma rays pass through an object, they will be exposed to light on the film, leaving an image. By analyzing these images, people can know whether the object is defective or not.
Gamma knife and radiotherapy are commonly used in medical treatment. X-ray also plays a great role in medical treatment, but it is mainly used for human image examination, which can see the state inside the human body. The energy of γ -rays is much larger than that of X-rays, which can penetrate the surface of human body to kill the lesions in the body, so that cancer cells and tumors in the body can be killed without leaving trauma, reducing the harm to the human body, and the parts that can be touched by trauma surgery can also be touched.
Radioactive sources for industrial flaw detection and medical treatment are based on the principle that radioactive elements will release gamma rays when beta decays, and cobalt -60 is generally used. Cobalt -60 is one of the radioisotopes of cobalt, with a half-life of 5.27 years. It will release high-speed electrons as high as 365,438+05 kev through beta decay, decay into nickel 60 and release two gamma rays at the same time.
Now, not only humans can benefit from gamma rays in nature, but scientists can also produce high-energy gamma rays. 20 1 1 In September, a team led by Professor Tino Janosinski of university of strathclyde, England, found that ultrashort laser pulses can react with ionized gas to produce extremely powerful laser.
The laser beam obtained by Professor Iarosinschi's team is 1 trillion times brighter than the sun. It can penetrate the lead plate with a thickness of 20cm, and the concrete wall with a thickness of 1.5 m can be completely shielded.
The most visible light in the solar electromagnetic spectrum is 480nm, which is 1 trillion times shorter than this wavelength, and the wavelength is 4.8 *10-21m. The corresponding frequency of such a short wavelength electromagnetic wave is 6.25 * 65,438+00 28 Hz, which is undoubtedly a gamma ray with extremely strong energy.
This creative discovery is of great significance, which may be applied to many fields in the future, such as better medical imaging and radiotherapy, and can also be widely used in industrial and scientific experiments. Because its duration is only 65438+ one millionth of a second, capturing the reaction of the nucleus to excitation quickly enough can further promote the in-depth study of the nucleus.
Therefore, mankind has long known and mastered the principle of gamma rays, and has long begun to use this natural law to benefit mankind. I wonder if my answer has solved this friend's problem? Thank you for reading and welcome to discuss.
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