X-rays are emitted from the focal point of the X-ray tube and radiate to the surroundings. The X-ray used in the inspection is just one of the directions. The collimator is emitted from the window of the sleeve. Taking into account the maximum range required for actual use, this beam of X-rays cannot be excessively restricted in the window, but a collimator is added outside the window for control.
The collimator is to use the lead plate with adjustable gap to hide the unnecessary original emission line emitted from the window, thereby controlling the size of the beam and changing the actual X-ray irradiation field used.
The relationship between focus, lead plate and irradiation field A / B = a / b.
A is the distance from the focus to the lead plate;
B is the distance from the focal point to the imaging surface;
a indicates the degree of lead leaf opening and closing;
b indicates the size of the irradiation field.
Generally, A is fixed; B is usually fixed for specific parts; in this way, the size of a can be obtained according to the requirements of b.