Two methods are used that allow to linearly correlating the mass of soil with information originated from the natural gamma radiation spectrum. The first method consists in adding the counts in a region of interest (ROI) of the original spectrum and correlating them with the mass of the sample. The second method uses the Continuous Wavelet Transformed and allows correlating coefficients wavelet with the mass of the sample. Due that for industrial applications low times of measurement are required, then the change of the coefficient of linear correlation as a function of the time required for each spectrum is studied. For a shilding wide of 6 cm and a measured time of 5 minutes, the coefficient of linear correlation is stabilized to an acceptable value for both methods.
Keywords: calibration curve, gamma-natural, Continuous Wavelet Transformed .