Izvorni znanstveni članak
Measurements of the breakdown potentials for different cathode materials in the Townsend discharge
M. Ali Hassouba
; Physics Department, Faculty of Science, Benha University, Egypt
F. Fahmy Elakshar
; Physics Department, Faculty of Science, Azhar University, Egypt
A. AbuWali Garamoon
; Physics Department, Faculty of Science, Azhar University, Egypt
Sažetak
The breakdown potentials have been measured for argon and helium discharges using three different cathode materials: aluminium, silver and magnesium. The measurements show that lower breakdown potentials are associated with lower work function of the cathode material. For the three different cathodes, the secondary ionization coefficients have been estimated using the measured values of the breakdown potentials and the first ionization coefficient, in the range 0.60 to 2.25 V/[Pa cm] (80 to 300 V/[torr cm]) for Ar discharge and in the range of 0.15 to 1.80 V/[Pa cm] (20 to 240 V/[torr cm]) for He discharge. The minimum breakdown potential has been found at (pd)min = 80 Pa cm (0.6 torr cm) in Ar discharge and at 530 Pa cm (4.0 torr cm) in He discharge.
Ključne riječi
discharge in gases; He; Ar; breakdown potentials; different cathode materials; secondary ionization coefficients
Hrčak ID:
301575
URI
Datum izdavanja:
1.5.2002.
Posjeta: 192 *