Because there are many factors that affect the X-ray exposure time, it cannot be directly calculated by formula, and the radiation source of each machine is different, because besides the factors of the detected object, it also includes the factors of the X-ray machine itself, such as the model of the machine, the brand of the manufacturer, the heat dissipation capacity, the continuous running time and the stability of the X-ray machine.
X-rays have strong penetrating power and can penetrate many substances that are opaque to visible light. This invisible ray can make many solid substances have visible fluorescence, make photographic negatives sensitive and ionize air. X-rays were originally used for medical imaging diagnosis and? X ray crystallography.
Therefore, in order to determine the exposure time of X-ray, it is necessary to do a contrast test, which is commonly called exposure curve. Different X-ray machines, different materials and different exposure methods make a complete set of exposure curves for reference in subsequent operations.
Extended data
The principle of x-ray
The simplest way to generate X-rays is to hit a metal target with accelerated electrons. During the impact, the electrons suddenly decelerate, and their lost kinetic energy (1%) will be released in the form of photons, forming a continuous part of the X-ray spectrum, which is called braking radiation.
By increasing the accelerating voltage, the energy carried by electrons increases, which may knock out the internal electrons of metal atoms. So the inner layer forms a hole, and the outer layer electrons jump back to the inner layer to fill the hole, and at the same time emit photons with a wavelength of about 0. 1 nm.
Because the energy released by the outer electron transition is quantized, the wavelength of the released photons is also concentrated in some parts, forming a characteristic line in the X spectrum, which is called characteristic radiation.
Baidu encyclopedia -X-ray