The HADES RPC inner TOF wall

Abstract The upgraded HADES inner TOF Wall will cover a total area of 8 m 2 with 1116 variable-geometry 4-gap, symmetric, timing RPCs, readout by 2232 time and charge channels. Each RPC is individually shielded for robust multi-hit performance and optimum use of the readout channels (crosstalk minimization). The double layer configuration provides a useful degree of redundancy for very accurate timing of a large fraction of all particles crossing the detector. In this paper we describe the concept of the detector, its inner structure and the multi-hit performance.