Whenever the doctor tells you to take a film, are you nervous? Do you stay away every time you pass the radiology department and feel like you have been exposed to radiation?
So, does X-rays really affect our health?
What exactly is X-ray?
X-rays have been taken by many people, but what kind of light is it? From where? How does it go through your body?
In fact, X-rays are high-energy electromagnetic waves with short wavelengths, which are generated by the transition of electrons in the inner orbits of atoms or the deceleration of high-energy electrons .
The wavelength of X-rays generally ranges from 0.01 to 100? (1? = 10-8cm), which is between ultraviolet and g-rays, with some overlap.
We know that the wavelength of visible light is between 400 ~ 700nm (1 nm = 10-7cm), and as an invisible "light", its wavelength is much shorter than the wavelength of visible light.
In the air, X-rays travel at the same speed as visible light, and are essentially the same electromagnetic waves as visible light, so they have properties similar to visible light, electrons, protons, and neutrons, namely wave-particle duality.
From the perspective of volatility, X-ray is an electric field with sinusoidal oscillation that changes with time, and its vertical direction is a similarly changing magnetic field.
From the perspective of particle nature, X-rays consist of a large number of particles with a certain energy moving at the speed of light. These particles are called light quanta, or simply photons.
X-ray fluctuations and particles are coexisting. Therefore, when analyzing the problem of X-ray propagation, mainly consider the fluctuation; when analyzing the interaction of X-rays and matter, mainly consider the particle.
X-rays with different frequencies and wavelengths have different photon energies. The frequency is high, the wavelength is short, and the photon energy is large.
Compared with visible light, in addition to the duality of wave-particle duality, X-rays also show other characteristics due to their short wavelength and high energy: such as strong penetrability, and the ability to penetrate materials that cannot be penetrated by visible light, such as biological soft tissue , Wood, ordinary glass, and even metal plates other than heavy metals, can also ionize the gas; the refractive index is almost equal to 1, so it cannot be focused by refraction; diffraction occurs when passing through the crystal, so it may be X-ray to study the internal structure of the crystal.
The X-ray penetrating power is determined by the X-ray photon energy, not the X-ray intensity.
The intensity of X-rays at a certain frequency depends on the number of photons that pass through a unit cross section per unit time.
Since X-rays have a strong lethality to biological cells and tissues, care should be taken to protect X-rays with lead plates, lead glass or lead rubber.