Application of the time-dependent charge asymmetry method for longitudinal position determination in prototype proportional chambers for the PANDA experiment

The PANDA collaboration intends to build a state-of-the-art detector to study the physics of antiproton annihilation in the charm mass region at the future FAIR facility at GSI, Darmstadt. One major part of the PANDA detector is the straw tube tracker. It will consist of about 6000 individual straws grouped in 11 double layers and filled with an Ar+10%CO_2 gas mixture. The required radial spatial resolution is about 150 micron. Two different methods are considered for longitudinal coordinate measurements - skewed double layers and a novel method based on the time-dependent charge asymmetry. The latter method is presented in this article.