Background: Emission of Secondary electron from material surface is the key parameter
which defines all properties of plasma bounded by that surface. In dc glow discharge plasmas, these
emitted electrons from the cathode provide the necessary feedback to sustain the discharge. There are
various processes responsible for emission of electron from the cathode surface. The most dominant
among these processes are bombardment of energetic neutrals, excited atoms or molecules, photons,
surface reactions etc. in addition to the ion induced secondary electron emission. Further, among these
various governing processes contribution of each process, to secondary electron yield vary according to
the operating discharge condition. The secondary electrons emitted due to all the above mentioned
processes are called Effective Secondary Electron Emission Coefficient (ESEEC). Measurement of
ESEEC is highly desired in theoretical as well as experimental gas discharge physics. In this work, we
propose a novel model for estimation of ESEEC and the results were obtained using this model for
cathode material made up of Brass.
Methods: A self-consistent model for measurement of ESEEC is developed under glow discharge
plasma condition. It requires knowledge of only two experimental parameters namely total discharge
power across the electrode (PT) which is product of discharge current (I) and applied voltage (V) and the
fraction of power carried by ion to the cathode (Pi) to estimate the value of ESEEC. The power carried
by ion to the cathode has been estimated using power balance at cathode.
Results: The measured value of ESEEC varies from 1.65 - 0.81 for the constant cathode bias of -600 V
and pressure range of 0.08 - 0.4 mbar. The obtained experimental results are verified by two methods of
power influx measurement namely, from the slope of temporal temperature profile of cathode while
cooling and heating cycles and from the Stefan’s Boltzmann Law at saturation temperature of the cathode.
The obtained values of power influx from both the methods are in good agreement with each other.
Conclusion: A self consistent model for measurement of ESEEC has been proposed. Using this model,
the value of ESEEC for Brass has been successfully obtained, under glow discharge plasma condition.
The proposed model is based on power balance in a discharge process and requires measurement of
only two discharge parameters, namely, total discharge power (PT) and the fraction of discharge power
carried by ions i.e. (Pi). This model may be applied over wide range of operating parameters to obtain
the value of ESEEC for different materials.