X-ray Shielding of an Ionizer using Low-Energy X-rays below 9.5 keV for Ultra-Clean Assembly Line of Electronic Devices

摘要

An ionizer has been developed using a low-energy X-ray for producing ion pairs that are transported by clean air through a shielding plate to objects to be discharged. The shielding plate should shield the X-ray of below 9.5 keV, while it should pass sufficient amount of the ion pairs. In this study, characteristics of the structural condition of the shielding plate has been investigated, on both the shielding effect and the ability to pass the ion pairs. We confirmed the structural condition that the leakage dose rate of the low-energy X-rays could be decreased to less than 1 μSv/h while allowing the passage of enough ion pairs to eliminate the static electricity.