The Limiting Energy Resolution of SiC Detectors in Ion Spectrometry

Abstract

The Monte Carlo method is used to simulate the complete stopping of α particles in SiC. A histogram of energy losses in nuclear-scattering events is obtained. The energy-loss spectrum has the characteristic asymmetric shape with the line full width at the half-maximum FWHM_nucl ≈ 4.22 keV. The final shape of the spectral line is obtained by a convolution with the Gaussian function that describes the contribution of the ionization and noise fluctuations (originated in the detector and instrumentation) to the signal. The resulting value of FWHM for the line is equal to 8.75 keV (at a noise variance of 1.7 keV). The experimental energy resolution of the detectors was found to be poorer than the calculated value by a factor of 2. It is established that the losses of charge during its transport in the detector bulk are insignificant, so that the discrepancy between the calculated and experimental values of the resolution should be attributed to the nonoptimal design of the detector window.