The use of low energy X-rays for device testing - A comparison with Co-60 radiation

Low (about 10 keV) energy X-ray sources have been proposed as alternatives to Co-60 for device testing. Several effects caused by differences in the photon energies of the two types of sources are evaluated. Quantitative estimates of the magnitude of these effects and other factors which should be considered in setting up test protocols are presented. Several cases are defined where the differences in the effects caused by X-rays and Co-60 are expected to be small. Other cases where the differences may be as great as a factor of five are described. Lateral spreading of the collimated X-ray beam beyond the desired irradiated chip region is also discussed.