The Principle And Construction Of An X-ray Machine

X-ray was discovered by Professor Roentgen of Germany in 1895. This type of radiation line emitted by a vacuum tube that can penetrate objects has higher energy, shorter wavelength, and higher frequency in the electromagnetic spectrum compared to visible light. Similar radiation lines include cosmic rays, X-rays, etc. [5].
To generate X-Ray, an X-ray tube is required, and the basic structure of the X-ray tube must have:
Cathode filament
Anode target
Evacuated glass envelope
Of course, there is also a power supply and energy supply
X-ray is an electromagnetic wave with a very short wavelength. The wavelength range is 0.0006-50nm. The commonly used X-ray wavelength range in X-ray security inspection is 0.008-0.031nm (equivalent to 40-150kV). In the electromagnetic radiation spectrum γ The wavelength between radiation and ultraviolet light is much shorter than that of visible light, and is not visible to the naked eye.
X-ray imaging mainly utilizes the penetrability, fluorescence effect, and photographic effect of rays
Interaction between X-rays and objects
1. Photoelectric effect
2. Compton scattering (incoherent scattering)
3. Rayleigh scattering (coherent scattering)
4. Electron couple effect
The process of X-ray generation is to first connect the power supply, pass through a step-down transformer, and heat the X-ray tube filament, generating free electrons and gathering near the cathode. When the step-up transformer supplies high-voltage electricity to the two poles of the X-ray tube, the potential difference between the cathode and anode increases sharply, and the free electrons in the active state are strongly attracted, so that the bunched electrons travel from the cathode to the anode at a high speed, hitting the atomic structure of the anode tungsten target. At this point, energy conversion occurs, with less than 1% of the energy forming X-rays and more than 99% being converted into thermal energy. The former is mainly emitted by the X-ray tube window, while the latter is emitted by the heat dissipation facility.