Studies of electron drift velocity and charge spectra in RPC by a UV laser source

We report on electron drift velocity and gas amplification properties in a ATLAS-like Resistive Plate Chamber (RPC) prototype. The prototype is operated in saturated avalanche regime with 94.7 % C 2 H 2 F 4 + 5 % C 4 H 10 + 0.3 % SF 6 gas mixture. The primary ionization is induced by a well focused UV laser source in a reproducible manner and varying intensity, spot position inside the active gas volume and gas amplification. The obtained values of drift velocity and gas amplification were compared to the values calculated by the program MAGBOLTZ. Finally, pulse height spectra was recorded and characterized showing three well distinct electron avalanche regimes.