The HERMES forward tracking chambers: construction, operation, and aging effects

Abstract The design, construction and operation of the HERMES forward (front) tracking chambers and associated electronics are described. Resolution and limited aging tests have been performed on these drift chambers, which use an Ar/CF 4 /CO 2 (90 : 5 : 5) gas mixture. No degradation in chamber performance has been observed for a cumulative charge in excess of 9 C / cm .