Integrated Experimental–GEANT4–ROOT Determination and Discrepancy Analysis of the Half-Lives of Cs-137, Sr-90 and Eu-152

摘要: Reliable half-life determination requires more than fitting an exponential curve: the result depends on source characterization, detector response, background correction, calibration, statistical estimation and the reference nuclear-data set used for comparison. This study develops an integrated experimental–computational framework for determining and evaluating the half-lives of Caesium-137 (Cs-137), Strontium-90 (Sr-90) and Europium-152 (Eu-152), three radionuclides selected to represent contrasting radiation-measurement problems. Cs-137 was measured by background-corrected radiation counting, Sr-90 by Geiger Müller beta counting with explicit consideration of the Sr-90/Y-90 parent daughter system, and Eu-152 by high-purity germanium (HPGe) gamma-ray spectrometry. GEANT4 11.3.2 was used to model radioactive decay and radiation transport, while ROOT was used for Gaussian photopeak analysis, nonlinear exponential fitting, residual analysis and goodness of fit evaluation. The measured/simulated half-lives were compared with adopted evaluated values using absolute difference, percentage deviation and uncertainty-based standardized differences. Cs-137 gave 29.96 ± 0.12 years experimentally and 30.045 ± 0.020 years from GEANT4, against 30.018 ± 0.022 years as the adopted reference. Sr-90 gave 28.98 years experimentally and 27.95 ± 1.35 years by GEANT4, against 28.80 ± 0.07 years. For Eu-152, the experimental and GEANT4 estimates were 14.83 ± 0.21 and 14.43 ± 0.22 years, respectively. Using the consistently documented Eu-152 reference of 13.517 ± 0.009 years, the corresponding deviations are 9.71% and 6.75%. The results demonstrate that the integrated workflow can reproduce expected decay behaviour and detector response while also revealing radionuclide-specific systematic sensitivities. The largest residual discrepancy occurs for Eu-152, where HPGe efficiency, source geometry, self-attenuation, coincidence summing and calibration assumptions require further control. The study therefore supports uncertainty-aware integration of measurement, Monte Carlo transport and statistical analysis for nuclear metrology and radiation-detection research.