def _Ep(self):
        """ Proton energy array in GeV
        """
        return np.logspace(
            np.log10(self.Epmin.to("GeV").value),
            np.log10(self.Epmax.to("GeV").value),
            int(self.nEpd * (np.log10(self.Epmax / self.Epmin))),
        )
Proton energy array in GeV