Function of X-ray Colimator
X-RAY collimator is the important part of X-ray machine, and its main function is confine the scope of X-ray beam, to reduce the radiation harm to Patients; Another function is realizing the multi scope exposure on one film working with the film motion and shielding system.
In order to keep the field of illumination unchanged with the change of focal screen, function of X-ray Colimator has also set up a focal screen detection device in the circuit, which converts the focal screen into electrical signal and superimposes it on the irradiation control signal as a distance correction signal. When the focus screen decreases, the correction signal makes the function of X-ray Colimator drive a little bigger, and vice versa. So that after the initial adjustment of the irradiation field, no matter how the distance changes, the irradiation field of the input screen is always reserved. Focus screen signal lamp detection methods are divided into two types: grading and continuous. The dividing type uses the switch set on the fixed distance as the correction signal, and it can only roughly achieve the dividing tracking. Continuous potentiometer is usually used to detect. With the change of focal screen, potentiodynamic device can be adjusted accordingly, so it can achieve strict real-time tracking.