Performance of a GEM-TPC prototype

A GEM-TPC detector was build as a prototype of the inner tracker for the future \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$\overline{\rm P}$\end{document}ANDA experiment at FAIR and as an updgrade for the FOPI experiment at GSI. A GEM-TPC can exploit the intrinsic suppression of back drifting (Lyashenko A et al., Nucl Instrum Methods A 598:116, 2009) ions from the amplification stage of the GEM foils to overcome the problem of drift-field distortions in a ungated operation. This prototype was designed to fit into the FOPI spectrometer, where the commissioning, tests with cosmic rays and beam tests were carried out (Fabbietti, Nucl Instrum Methods A 628:204–208, 2011).