RPID - A new digital particle identification algorithm for CsI(Tl) scintillators

A new digital algorithm for online particle identification in CsI(Tl), called Reconstructive Particle IDentification (RPID) is reported. The concept is based on a model for the signal generation with two exponential components for the scintillation light output and an exponential response function of the preamplifier. To provide a fast algorithm which could be used online in modern FPGA-based electronics a simplified method for signal deconvolution was developed. Within a few simple processing steps the original pulse shape is modified to recover the amplitudes of the two scintillation components that determine the type of particle. Data from an experiment C-12(p, p')C-12* at 21 MeV allowed to separate gamma-rays and protons even of very low energies. We present the performance of this new algorithm concerning the gamma-proton separation as well as the identification of protons not fully stopped within the CsI(Tl).