Experimental Evaluation of the Response and Recovery Times of Geiger-Müller Counters

Abstract

This work experimentally evaluates the dynamic behavior of digital and analog Geiger-Müller (GM counters under operational conditions in a facility housing ionizing radiation sources. Although these instruments are widely used in radiation protection, their temporal response to abrupt changes in dose is not always considered in practice. For this study, quantitative criteria were defined to determine the response time (exceeding 90 % of the maximum recorded dose rate) and the recovery time (returning withing 10 % of the reference value). Measurements were obtained through video analysis with a temporal resolution of 1/30 s, and five repetitions were performed for each condition. Time uncertainty was estimated as Type A in accordance with the GUM, and ANOVA and Tukey tests were applied to evaluate differences among indication channels (numerical, audible, and visual). The results show that the characteristic times, on the order of seconds, depend significantly on the instrument type and output channel, being greater for numerical indicators than for alarms. The observed behavior is dominated by signal processing electronics rather than detector dead time, indicating that quantitative reading is not strictly instantaneous in scenarios involving rapid dose rate variations.