![]() In this report, we have discussed the calculation of gas phase fugacity in NH/sub 3/-H/sub 2/S-H/sub 2/O and NH/sub 3/-CO/sub 2/-H/sub 2/O systems. For some of these mixtures, the above transport and dielectric strength measurements have been performed over the concentration range from 0 to 100% of the attaching gas in the nonattaching buffer gas. In this paper, we will present measurements of the electron drift velocity, attachment, diffusion and ionization coefficients, and high voltage dielectric strengths of several gas mixtures proposed as candidates for use in diffuse discharge switching applications. In the opening stage, strong electron attachment along with high dielectric strength is required of the gas mixtures in order to extinguish the discharge more » as quickly as possible (and, thus, achieve a fast opening time) to prevent arcing occurring between the switch electrodes due to the high voltages induced across the switch in the opening phase. ![]() In the conducting stage, the electron drift velocity must be large, and the electron loss processes (e.g., due to electron attachment and recombination) must be low so as to maximize the efficiency of the current gain in the discharge while maintaining low discharge impedance. Gas mixtures for possible use in diffuse discharge switching applications require both high dielectric strength and specific transport properties in the conducting and the opening stages of the operation of the switch. Our attachment and breakdown measurements for these gases and gas mixtures are reported and discussed. The dc breakdown strength of 1-C/sub 3/F/sub 6/ is dependent on the total gas pressure after allowing for the effect of compressibility of the gas. These measurements have been performed over the total pressure range 25 to 600 kPa. Breakdown measurements have been performed in 1-C/sub 3/F/sub 6/ using uniform field electrodes and in mixtures of 1-C/sub 3/F/sub 6//N/sub 2/ and 1-C/sub 3/F/sub 6//SF/sub 6/ using point-plane electrodes. ![]() 15 kPa, indicating that the attachment process involves the interaction of two or more 1-C/sub 3/F/sub 6/ molecules. ![]() A partial pressure dependence of the attachment rate on 1-C/sub 3/F/sub 6/ has also been observed in these mixtures, which may saturate above approx. A considerably larger total pressure dependence has been observed for 1-C/sub 3/F/sub 6/ in N/sub 2/ and Ar, which does not saturate, even at the highest buffer gas pressures (3.2 MPa). ![]() = 1 eV, and more » in Ar over the energy range from approx. 700 kPa in N/sub 2/ over a mean energy range of from thermal energy to approx. It has been observed that the higher order perfluoroalkanes (n-C/sub N/F/sub 2N+2/ 3 less than or equal to N less than or equal to 6) exhibit a marked dependence of their attachment rate constant on the total gas pressure, particularly in the pressure range from 53 kPa to approx. The pressure dependence of the attachment rate constant of several perfluoroalkane dielectrics has been studied in buffer gases of N/sub 2/ and Ar up to a total pressure of 2.4 MPa. ![]()
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