Garfield++/LTSpice Studies of the Straw Tube Time and Charge Resolution for Various Readout Parameters

The Straw Tracker of the SPD detector should provide track coordinate measurements and also should serve the Particle Identification of low momentum charged particles. This requires simultaneous precise measurement of the signal time and charge, so optimization of the readout electronics parameters is necessary. Different parameters, such as the preamplifier gain, shaper peaking time, discriminator threshold and electronics noise level are studies. Time and charge distributions are obtained. The drift time distributions for various discriminator threshold levels and shaper peaking times are analyzed in order to reach the best tracking performance. Influence of the peaking time on the precision of charge measurements is studied as well. Comparison between the experimental data and modeling results is presented.