High-precision measurement of the electron drift velocity in Ne-CO2

The baseline gas mixture which will be used in the ALICE TPC is 90% Ne and 10% CO2. The change of the drift velocity due to changes of the CO2 concentration as well as N2 addition has been studied in high-precision measurements at drift fields between 100 and 900 V/cm. Also a precise absolute measurement of the drift velocity has been made. All measurements are compared with calculations.