Determination of effective electron yield from swarm and time delay measurements

The primary aim of this paper is to determine the dependence of the effective secondary emission coefficient - electron yield γ7eff in nitrogen on the reduced field, i.e. the ratio of the electric field and pressure of the gas E/p. The yield γ7eff is an effective coefficient, which includes ion, excited states and photon impact on the cathode. The time delay method is used in order to derive the secondary electron yield and compare it to the data obtained from a swarm measurements, including pre-breakdown, breakdown and low-current discharge measurements, which can also be used to provide the effective electron yields per ion. The swarm results obtained from the breakdown and low-current discharge maintenance voltages, the well known Paschen curves. The secondary electron yield is obtained by applying relations with constants A and B from our fit to the experimental data. Application of the breakdown time delay method is demonstrated, and the results are compared with swarm measurements. The γ7eff is calculated from probability point by point or by fitting probability with linear dependence of γ (E/p). The swarm results with corrections for delay distance d0 in electron multiplication exp [{α (d - d0}, are also shown. The values of d0 were calculated by Monte Carlo simulation