Segmented G(E) Function Compensation Method for Gamma Dose Rate Meters Considering Asymmetric Error Distribution Across Energy Regions

Gamma dose rate meters are used in environmental radiation monitoring and radiation safety assessment. Conventional global G(E) functions can concentrate dose conversion errors at low energies. A segmented G(E) compensation method based on the multi-segment least-squares method (MSLSM) was developed for a compact CsI(Tl)–silicon photomultiplier (SiPM) meter, with separate functions for 20–200 keV and 200 keV < E ≤ 2000 keV. Full-spectrum fitting mean absolute percentage error (MAPE) decreased from 10.36% to 5.83%, a relative reduction of 43.73%, while low-energy MAPE decreased from 22.32% to 11.42%. For simulated nuclide spectra, the 241Am relative deviation decreased from 9.17% to 1.83%; results for 137Cs, 60Co, and most mixtures were comparable to or slightly better than those of the conventional global least-squares method (LSM). After correction, the maximum absolute relative deviations between the prototype meter and the commercial SAM945 instrument were approximately 7.5% for 137Cs and 14.91% for 60Co. Segmented G(E) modeling thus improves the regional error distribution and dose rate fitting accuracy over a wide energy range for the detector studied.