[en] A recently used experimental technique for measuring the mobility of positive ions in their parent gases is applied to methane (CH₄ purity ≥99.995%), where ion reduced mobility values K₀ are deduced from the analysis of measured time-of-arrival spectra of the ions produced by a GEM. For CH₄ pressures in the range 3 to 10 Torr, two peaks could be observed when reduced applied fields E/N were varied from 10 to 60 Td, where E/N is the ratio of electric-field strength to gas-number density. The corresponding extrapolated zero-field mobility values in CH₄ were found to be K₀ = 2.58 cm² V⁻¹ s⁻¹ and K₀ = 2.42 cm² V⁻¹ s⁻¹, belonging likely to CH₅⁺ ions on the 1^st peak and to C₂H₅⁺ and C₃H₇⁺ ions, with similar mobility values and falling both under the 2^nd peak.

[en] A recent experimental technique was used for measuring the mobility of positive ions originated from ethane in their parent gas. In this particular experiment, measurements were made in pure ethane (C₂H₆) for pressures ranging from 6 to 10 Torr and for reduced electric fields varying from 6 to 42 Td. The time of arrival spectra revealed two peaks and their reduced mobilities were determined. Extrapolation to zero field led to the values of 1.58 cm²V⁻¹s⁻¹ and 1.47 cm²V⁻¹s⁻¹, which are likely to belong to a 3-carbon ions group which includes C₃H₅⁺, C₃H₇⁺, C₃H₈⁺ and C₃H₉⁺ and to a 4-carbon ions group which includes C₄H₉⁺ and C₄H₁₀⁺ ions. For typical reduced electric fields used in gaseous detectors (E/N > 15 Td), the mobilities were 15% smaller than the Langevin limit [1]

[en] In this paper we present the experimental results for the mobility of ions in argon-ethane gaseous mixtures (Ar-C₂H₆) for pressures ranging from 6 to 10 Torr and for reduced electric fields in the 10 Td to 25 Td range, at room temperature. For Ar concentrations below 80% two peaks were observed in the time of arrival spectra which were attributed to ion species with 3-carbons (C₃H₇⁺, C₃H₈⁺ and C₃H₉⁺) and with 4-carbons (which includes C₄H₇⁺, C₄H₉⁺, C₄H₁₀⁺ and C₄H₁₂⁺ ions). For Ar concentrations above 80% a third peak appears, which may belong to C₅H₁₁⁺. The time of arrival spectra for Ar concentrations of 80%, 85%, 90% and 95% are displayed in the present paper as well as the reduced mobilities determined from the peaks observed for a typical reduced electric field used in gaseous detectors (E/N = 15 Td)

[en] In this paper we present the results of the ion mobility measurements made in gaseous mixtures of argon (Ar) and methane (CH₄) for pressures ranging from 5 to 8 Torr and for low reduced electric fields (in the 17 Td to 43 Td range), at room temperature. The time of arrival spectra of the several mixture ratios studied revealed that the relative abundance of the ions formed depend on the mixture ratios. For CH₄ concentrations in the 2.5–10% range three well defined peaks were observed which were attributed to single-carbon ions (CH₅⁺), 2-carbon ions (C₂H₄⁺ and C₂H₅⁺), and 3-carbon ions (C₃H₄⁺, C₃H₅⁺, C₃H₆⁺ and C₃H₇⁺). The time of arrival spectra for CH₄ concentrations of 2.5% (P-2.5), 5% (P-5), 10% (P-10) and the reduced mobilities of the ions obtained from the peaks observed are presented in this paper. The ion mobility study was performed for typical reduced electric fields used in gaseous detectors (E/N > 15 Td)

[en] In this paper we present the experimental results for the mobility of ions in argon-carbon dioxide gaseous mixtures (Ar-CO₂) for pressures ranging from 6 to 10 Torr and for reduced electric fields in the 10 Td to 25 Td range, at room temperature.The time-of-arrival spectra of the several mixture ratios studied revealed that the relative abundance of the ions and their mobilities depend on the mixture ratio. For Ar concentrations below 80% only one peak was observed in the spectra which was attributed to CO₂⁺, while for Ar concentrations above 80% a second peak appears at the left side of the main peak, which may be due to impurities, probably H₂O⁺. In this work, the time-of-arrival spectra from which reduced mobilities were obtained for Ar concentrations of 20% (K₀ = 1.141±0.004 cm²V⁻¹s⁻¹), 50% (K₀ = 1.385±0.009 cm²V⁻¹s⁻¹), 85% (K₀ = 1.690±0.022 cm²V⁻¹s⁻¹) and 95% (K₀ = 1.954±0.043 cm²V⁻¹s⁻¹) are displayed as well as other reduced mobilities values obtained similarly. The ion mobility study was performed at reduced electric field values typically used in gaseous detectors

[en] Neutrinoless double beta decay measurements are the most promising experiments both to reveal the Majorana nature of the neutrino and to set a value for its mass. The NEXT project propose to build a High pressure Xenon TPC in the Canfranc Underground Laboratory (Huesca, Spain) to measure double-beta decay of ¹³⁶Xe, both normal and neutrinoless, with a source mass of 100 kg of enriched xenon.