Noise lower limit calculation for SuperB DCH Cluster Counting front-end electronics

Cluster counting technique [1] can improve particles identification in tracking devices, like drift chambers, by removing Landau tails. The technique is based on the counting of primary ionization clusters and, to be implemented, it requires slow drift velocity gas mixtures, fast amplifiers, fast sampling devices (> 1GS/s) and, finally, correct termination of the sense wire (to avoid signal reflection). Because the termination resistor low value, its noise contribution is not negligible then setting a lower limit on the readout chain noise.