Measurements of the electron drift velocity and positive-ion mobility for gases containing CF4 have been performed. The results are presented for four types of gas mixtures containing CF4 and hydrocarbons: CF4+CH4, CF4+C2H6, CF4+C3H8 and CF4+iso-C4H10. To make a comparison, also positive-ion mobilities for Ar+C2H6 and Ar+C3H8 gas mixtures have been measured. The drift velocities of electrons in a few mixtures are found to exceed 10 cm/μs, twice that in a conventional drift chamber gas such as Ar(50%)+C2H6(50%). In particular, the electron drift velocity in CF4(10%)+CH4(90%) is larger than 10 cm/μs, even at a reduced electric field E/P of more than 1 V/(cm Torr). Results on the measurements of the positive ion mobility are consistent with the interpretation that the hydrocarbon ions are the positive ions eventually drifting toward the cathode in the studied gas mixtures. Their mobilities in CF4 are found to be smaller than those in Ar.
ASJC Scopus subject areas
- Nuclear and High Energy Physics