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52 SMT007 MAGAZINE I APRIL 2025 Figure 5: Dependence on dosage on: a) filter material and thickness; b) tool parameters for inspection; c) inspection time; d) board thickness. Variability Chart for Dosimeter reading (rad) Variability Chart for Dosimeter reading (rad) shows the dosage readings for the BGA #3. In the case of a 3D X-ray scan, the readings are highest for Pos C, as expected, as there is more material absorbing radiation on Pos A and Pos B. However, for the 2D X-ray, the order of readings is reversed. Pos A sees the highest radiation even though it is the most shielded. is is because the amount of dos- age absorbed also depends on the method and the actual path of the X-ray scan. Figure 5 provides a detailed analysis of var- ious factors affecting dosage in X-ray imag- ing. In Figure 5a, the impact of different fil- ter materials on dosage is highlighted, show- ing that copper is the most effective material for reducing dosage. is suggests copper's superior filtering capability in attenuating X-rays compared to other materials. How- ever, Figure 6 shows the image quality with the three materials of equal thickness and, although copper provides the most shielding from radiation, it is quite ineffective to pro- duce the image quality needed for inspec- tion. Aluminum, on the other hand, seems to provide effective shielding and preserve the image quality as seen in Figure 6. Figure 5b examines the influence of tube power and voltage on dosage. It reveals that while tube power significantly affects dos- age at a constant tube voltage, variations in tube voltage have a minimal impact on dosage when X-ray power is kept constant. Figure 5c demonstrates a linear relationship between inspection time and dosage, indicating that longer exposure leads directly to higher dos- age. Lastly, Figure 5d illustrates a decreasing Bivariate Fit of Dosimeter Reading (rad) by Inspection Time (Sec) Bivariate Fit of Dosimeter Reading (rad) by Inspection Time (Sec) a b c d