The lineshapes of two-dimensional angular correlation of electron-positron annihilation radiation (2D-ACAR) were determined for different base adsorbed Y-zeolite under a temperature controlled heating system in order to investigate the acid strengths and concentrations of Bronsted sites in the samples. Results demonstrated that the lineshape parameter of the angular correlation spectrum of the sample increases with the strength of adsorbed base and decreases with the acidity concentration of samples. This indicated that the lineshape parameter is sensitive to both the strength and concentration of Bronsted acid sites in the sample.
