The upgraded inner TOF Wall covers a total area of 8m2 with 1116 variable-geometry 4-gap, symmetric, timing RPCs, readout by 2232 time and charge channels. The detector is divided in 6 sectors of trapezoidal shape. Each RPC counter 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 tail-free timing of a fraction o fall particles crossing the detector.
The inner TOF Wall conform to the following parameters:
- Multi-hit capability: hit-lossprobability below 20% for the heaviest system considered;
- Granularity (determined by the multi-hit capability): 150 channels/sector effective cluster size;
- Resolution: below 100ps;
- Rate capability: up to 1kHz/cm2 in the innermost part;
- Efficiency: above 95% for single hits;
- Area: 8/6m2/sector.