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

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/CF4/CO2 (90: 5: 5) gas mixture. No degradation in chamber performance has been observed for a cumulative charge in excess of 9 C/cm. (C) 2001 Elsevier Science B.V. All rights reserved.