What are open x-ray tubes and closed x-ray tubes and what are the differences between them?
An x-ray tube is the device that produces the x-ray radiation for the inspection system. In essence, an x-ray tube is an evacuated cylinder within which electrons are produced, accelerated by an applied voltage and driven to strike a metal target. The effect of the electrons hitting the target is to produce the x-rays. The vacuum is required within the tube so that the electrons can travel down to the target without being absorbed by atmospheric contamination. Traditionally, x-ray inspection systems have used what are called closed x-ray tubes, where the vacuum is produced during manufacture and the tube sealed allowing no access to the components within. In recent years, open, or demountable, x-ray tubes have become more popular, if not the norm, for PCB and semiconductor x-ray inspection because of their ability to provide much higher magnification, much better resolution and serviceability (by allowing access to the consumable items of target and filament). In open x-ray tubes, evac
