Five characteristics of x-ray

(1) penetration. Because of its short wave length and high energy, when X-rays irradiate on matter, only a part of them are absorbed by matter, and most of them pass through atomic gaps, showing strong penetration ability.

The ability of X-rays to penetrate matter is related to the energy of X-ray photons. The shorter the wavelength of X-ray, the greater the photon energy and the stronger the penetrating power. The penetrating power of X-rays is also related to the density of substances, and substances with different densities can be distinguished by using the property of differential absorption.

(2) ionization. When a substance is irradiated by X-rays, electrons outside the nucleus can leave the atomic orbit to produce ionization. X-ray exposure can be measured by ionizing charge, and the X-ray measuring instrument is made according to this principle. Under ionization, gas can conduct electricity; Some substances can react chemically; Various biological effects can be induced in organisms.

(3) fluorescence. X-ray wavelength is too short to see, but when it irradiates some compounds such as phosphorus, platinum barium cyanide, zinc cadmium sulfide, calcium tungstate and so on. It can make substances emit fluorescence (visible light or ultraviolet light), and the intensity of fluorescence is directly proportional to the number of X-rays.

This function is the basis of X-ray application in fluoroscopy. Using this fluorescence function, we can make a fluorescent screen to observe the image of X-rays passing through human tissues during fluoroscopy, and also make a sensitizing screen to enhance the sensitivity of films during photography.

(4) thermal action. Most of the X-ray energy absorbed by the substance is converted into heat energy, which makes the temperature of the object rise.

(5) Interference, diffraction, reflection and refraction. These effects have been applied to X-ray microscopy (left), wavelength determination and material structure analysis.

Extended data

When X-rays are irradiated on organisms, biological cells can be inhibited, destroyed or even necrotic, resulting in physiological, pathological and biochemical changes in organisms to varying degrees. Different biological cells have different sensitivity to X-rays, which can be used to treat some diseases of human body, especially tumors (the picture below shows the X-knife for treating tumors).

At the same time of using X-rays, people have found problems that lead to patients' hair loss, skin burns, visual impairment of staff, leukemia and other radiation injuries. While using X-ray, we should also pay attention to its harm to normal body and take protective measures. ?

Baidu encyclopedia -X-ray