Distributions of the CP (panel a)) and LP (panel b)) at the positions of small Sunrise/IMaX MBPs. The red dashed line in panel a) marks the 4σ noise level and the vertical (black) solid lines in both panels represent the mean values of the histograms. The red dotted, dot-dashed and dashed vertical lines in panel b) indicate the 1σ, 2σ, and 3σ levels, respectively. The triple-dot-dashed curves represent the exponential fits to the histograms (see main text).