A Hybrid Pulse Pile-Up Rejection System as Applied to Rutherford Backscattering

The problems of pulse on pulse pile-up and noise limited pile-up rejectors are considered in detail for Rutherford backscattering spectra. The form of these spectra allow the distortions from pile-up and the residual pile-up after rejection to be understood via a simple model. Extended calculations allow us to predict the effects quite accurately. A new pile-up rejection system is described. The "linear" rejection method is implemented with peak stretchers and advantageously combined with an event counting rejector to provide a versatile high performance system.