Response simulation and primary vertex reconstruction in the SPDNICA straw tracker

In this work we investigate the temporal structure of the events in the spin physics detector (SPD) straw tracker at the JINR NICA. Using the Geant4 toolkit we simulate the response of the straw layers sensitive elements in the triggerfree regime of SPD. Using the simulation results we present a simple algorithm for the fast primary-vertex finding and estimate the efficiency and purity of the reconstruction.