Performance Evaluation of a Geiger-Müller Detector: Analysis of Statistical Stability, Dosimetry Linearity, and Geometric Efficiency

Abstract

Testing the performance of radiation detectors is essential to ensure the reliability of nuclear instrument counting before field monitoring or experimental deployment. This study aims to evaluate the operating stability, dosimetry response linearity, and geometric characteristics of a Geiger-Müller detector. The experimental methodology is divided into three main tests using a standard Am-241 source. First, a stability test was conducted using the Chi-Square method to verify conformity with the Poisson distribution in both indoor and outdoor environments. Second, a linearity test was performed to map the correlation between count rate (CPM) and dose rate (μSv/h). Third, distance variation tests were conducted to map the spatial geometric efficiency of the system. The Chi-Square statistical analysis confirmed that the detector operates highly stably, indicated by the calculated values remaining well below the critical table limits at a 0.05 significance level. In the linearity test, the detector exhibited a highly linear response (R2 > 0.96) with minor calibration factor variations between indoor and outdoor conditions correlated to the contribution of scattering radiation flux. Meanwhile, the distance variation results validated the Inverse-Square Law, where geometric efficiency and count intensity decreased exponentially with increasing distance due to solid angle reduction. In conclusion, the tested Geiger-Müller detector demonstrates reliable statistical, dosimetric, and spatial performance, rendering it qualified for environmental radiation protection monitoring.