Experimental ion mobility measurements for the LCTPC collaboration—Ar-CF₄mixtures

Abstract

In this paper we present the results of the ion mobility measurements made in pure carbon tetrafluoride (CF4) and gaseous mixtures of argon with carbon tetrafluoride (Ar-CF4) for pressures ranging from 6 to 10 Torr (8–10.6 mbar) and for low reduced electric fields in the 10 Td to 25 Td range (2.4-6.1 kV⋅cm−1⋅bar−1), at room temperature. The time of arrival spectra revealed only one peak throughout the entire range studied which was attributed to CF3+. However, for Ar concentrations above 70%, a bump starts to appear at the left side of the main peak for reduced electric fields higher than 15 Td, which was attributed to impurities. The reduced mobilities obtained from the peak centroid of the time-of-arrival spectra are presented for Ar concentrations in the 5%–95% range.

Experimental ion mobility measurements in Ar-N2

“…In this work, the mobility of ions in Ar-N 2 gas mixtures was measured at a pressure of 8 Torr (10.6 mbar) and for reduced electric fields commonly used in gaseous detectors, 15 Td (3.6 kV•cm −1 •bar −1 ), extending previous studies developed in our group for other gases [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22].…”

“…The mobilities calculated did not display a significant dependence with E/N for the values used in this work (10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25).…”

Ion mobility measurements in Ar-CO2, Ne-CO2, and Ne-CODeisting1, Garabatos2, Szabó3 2018Nuclear Instruments and Methods in Physics Research Section A:

“…Such distortions and their possible mitigation have been and are studied by many experiments as e.g. the current ALICE Time Projection Chamber [2] (TPC) [3], the upgraded ALICE TPC [4,5] and the LCTPC [6,7]. If K is known, it is possible to estimate and simulate this space charge and to evaluate the impact of the back drifting ions on the performance of a detector.…”

Experimental ion mobility measurements in Ne-CF4

“…E/N < 30 Td for the working pressures used. A background work on the mobilities and ionization processes of Ne [18,20] and CF 4 [21] in their parent gases has already been performed in our group.…”

“…The experimental setup has already been used and described in previous papers [10,[17][18][19][20][21]. The ion's velocity is obtained by measuring, with a digital oscilloscope (Tektronix TDS 2022B), the time that the ions take to drift under a uniform electric field, from a GEM [22] where they are originated to a grid located 4.273 cm above it.…”