Pulsed townsend electron and ion swarm parameter measurements of the trigger RPC standard mixture

The electron swarm parameters and ion drift velocities of the standard mixture R134a/iC4H10/SF6 95.2/4.5/0.3 used in trigger-purpose resistive plate chambers are examined in the pulsed Townsend experiment. Reduced electric fields up to 330 Td at pressures from 400 Pa to 12 kPa are investigated, whereby no significant pressure dependence of the reduced swarm parameters are observed. The acquired effective ionization coefficient and the bulk drift velocity agree with predictions made using the updated R134a cross-sections from the swarm parameter simulation software Magboltz version 11.19.