Performance of shower Xmax reconstruction by WFCTA upgraded telescope

摘要

The shower Xmax is an important parameter in describing shower longitudinal development. It can help to reconstruct shower primary energy more precisely. Furthermore, using Xmax information can help to discriminate primary composition of showers partly. WFCTA telescope will be upgraded in optical system, PMT cluster et. al. Using such an upgrading telescope, we test the performance of reconstructing shower Xmax. Showers that have different Xmax will have different angular distribution of Cherenkov photons. Small pixels with 0.5 degree of upgrading WFCTA telescope make it possible for us to obtain the photon angular distribution from the image. We research the method of extract photon angular distribution from the image. Then we study the performance of reconstruct shower Xmax with such information. We also study the method of using classical way to obtain Xmax information, that is using crossing of major axis of two images as the direction of Xmax.