Principle and structure

X-ray was discovered in 1895 by the German professor Roentgen. This kind of radiation emitted by the vacuum tube that can penetrate the object has stronger energy than visible light in the electromagnetic spectrum, shorter wavelength and higher frequency. Similar radiation has cosmic rays, X-ray and so on.

To generate X-Ray, there must be an X-ray tube, and the basic structure of the X-ray tube must have:

Cathod Filament (Cathod)

Anode target

Evacuated glass envelope

Of course there is also a power supply

X-rays are electromagnetic waves with very short wavelengths. The wavelength range is 0.0006 to 50 nm. X-ray wavelengths commonly used in X-ray security inspections range from 0.008 to 0.031 nm (equivalent to 40 to 150 kV). In the electromagnetic radiation spectrum, it is between gamma rays and ultraviolet rays, which is much shorter than the wavelength of visible light and invisible to the naked eye.

Radiography mainly uses the penetrability, fluorescence effect and photographic effect of rays

X-rays interact with objects

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Guangdong Nuoding Technology/ND-3500D model

1. Photoelectric effect

2. Compton Scattering (Incoherent Scattering)

3. Rayleigh Scattering (Coherent Scattering)

4. Electron couple effect

The procedure of X-ray generation is to first turn on the power supply and pass through the step-down transformer to heat the filament of the X-ray tube to generate free electrons and gather near the cathode. When the step-up transformer supplies high-voltage power to the two poles of the X-ray tube, the potential difference between the cathode and the anode increases sharply, and the free electrons in the active state are strongly attracted, so that the electrons in bundles travel from the cathode to the anode at high speed. , hitting the atomic structure of the anode tungsten target. At this time, energy conversion occurs, of which less than 1% of the energy forms X-rays, and more than 99% of the remaining energy is converted into heat energy. The former is mainly emitted by the X-ray tube window, and the latter is emitted by the cooling facilities.