Photon Attenuation Characteristics of Au–Sn Solder Alloys
El-Cezeri Journal of Science and Engineering, vol.13, no.3, pp.510-517, 2026 (Scopus)
- Publication Type: Article / Article
- Volume: 13 Issue: 3
- Publication Date: 2026
- Doi Number: 10.31202/ecjse.2016206
- Journal Name: El-Cezeri Journal of Science and Engineering
- Journal Indexes: Scopus
- Page Numbers: pp.510-517
- Keywords: Au–Sn solder alloys, Effective atomic number, Gamma-ray attenuation, Photon buildup factors, XCOM
- Istanbul Gelisim University Affiliated: Yes
Abstract
Lead-based solders have long been used in electronics; however, their use has declined following restrictions introduced by the Restriction of Hazardous Substances (RoHS) Directive. Au–Sn solders are attractive lead-free alternatives owing to their high service temperature, creep resistance, mechanical strength, and thermal stability, making them suitable for electronic packaging applications. Since electronic systems in radiation-exposed environments may be subjected to ionizing radiation, understanding the photon interaction characteristics of Au–Sn solders is important. The photon attenuation characteristics of four Au–Sn solder alloys with Au-Sn weight ratios of 80:20, 78:22, 75:25, and 73:27 were investigated over 1 keV–100 GeV using the XCOM database and Phy-X/PSD software. The parameters included the mass attenuation coefficient (μ/ρ), half-value layer (HVL), tenth-value layer (TVL), mean free path (MFP), effective atomic number (Zeff), transmission factor (TF), exposure buildup factor (EBF), and energy absorption buildup factor (EABF). Au–20Sn exhibited the highest μ/ρ, reaching 7.646 cm²/g at 81 keV following the sharp increase associated with the Au K-absorption edge (~80.7 keV). At 81 keV, increasing the Au–20Sn thickness from 10 to 150 µm reduced the TF from 89.48% to 18.87%. Differences among the alloys were greatest at low energies and decreased with energy.