Primary energy spectrum from the S(500) observable recorded with KASCADE-Grande

Studies have shown that for a particular EAS detector array the charged particle density at a given distance from shower core becomes independent of the primary mass and thus it can be used as a primary energy estimator. The particular distance for which this effect takes place is a characteristic of the array and in the case of the KASCADE-Grande it was shown to be 500 m. A Linsley parameterization has been used to describe the lateral particle density distribution of detected showers and to estimate the charged particle density at 500 m distance from shower core - S(500). The Constant Intensity Cut (CIC) method was applied to correct S(500) for attenuation. A calibration of S(500) with primary energy has been derived from simulated studies and used to construct a preliminary primary energy spectrum from the S(500) spectrum.