A Comparative Study of Gamma-Ray Attenuation for Low and High Gamma Energy Sources through Aluminum Foil using Scintillation Detector

Abstract

This research aims to investigate the attenuation behavior of gamma rays passing through aluminum foil absorbers of varying thicknesses. A comparative study was conducted between low-energy gamma rays from an Americium-241 (Am-241, 59.5 keV) source and medium-energy gamma rays from a Cesium-137 (Cs-137, 662 keV) source. The measurement system consisted of a Canberra NaI(Tl) scintillation detector (Model 802-2X2) connected to a processing system via Genie 2000 Spectroscopy Software, with a fixed counting time of 500 seconds. The results of the Net Peak Area analysis indicated that the attenuation behavior is significantly related to the energy level of the radiation. The main energy peak area of Am-241 showed a continuous downward trend, decreasing from 78,753 to 58,379 counts as the number of aluminum foil layers increased from 0 to 5 (total thickness of 0.15 mm). This reduction is attributed to the influence of the photoelectric effect in low-energy gamma radiation. Conversely, the main energy peak area of Cs-137 remained relatively constant across all thickness levels of the aluminum foil, indicating that aluminum foil with a thickness not exceeding 0.15 mm does not affect the attenuation of high-energy gamma rays.In conclusion, aluminum foil significantly affects the attenuation of low-energy gamma rays. These findings are beneficial for evaluating the influence of aluminum foil thickness in the detector's entrance window on the measurement accuracy of radiation across different energy levels.