Photoelectron Emission from the Quartz Surface of an Ultraviolet Lamp under Atmospheric Conditions

Abstract

Photoelectrons are emitted from the quartz surface of an ultraviolet lamp under atmospheric air conditions, and the lamp behaves like an electron emitter. The lamp used in the present experiment is 4 W and has light emission peaks at 185 nm and 254 nm. With this lamp, the emission current of the order of 10-9 A is produced in atmospheric air. This photoemission phenomenon is of great importance to charge elimination of charged matter.

Fast gas heating and radial distribution of active species in nanosecond capillary discharge in pure nitrogen and N2:O2mixtures

“…The maximum of the electron density on the periphery of the cross-section of the capillary tube can be explained by the interaction of UV radiation emitted by excited nitrogen species with the quartz wall of the capillary tube [35,41]. The quartz wall absorbs UV photons and emits electrons to the gas volume near the wall [42], which facilitates the discharge propagation and further electron production in this region. The tubular structure of the discharge in the tube can also be caused by an increase in the electric field near the wall due to the jump in dielectric permittivity [35,41].…”

A numerical modelling of microdischarge threshold in uniform electric fields

“…) where, α is Townsend's first coefficient of ionization, η the electron attachment coefficient, γ ph Townsend's second coefficient due to the action of photons, µ the photon absorption coefficient, Z i the distance travelled by the avalanche along the gap axis (figure 2) and g is a geometric factor to account for the fact that some photons are not received by the cathode [26]. It is worth mentioning that all the investigated air gaps are relatively long and the photons that may reach the dielectric surface are highly attenuated to the emission of electrons from a dielectric surface [27]. Thus, equation ( 10) is valid both in the presence and absence of the dielectric coating on the ground plate.…”

On the static behaviour of dielectric barrier discharges in uniform electric fields

“…The minimum threshold voltage corresponds to the case of an uncharged dielectric where the field in the gas gap is a maximum. Both the calculated threshold V th and suppression V sup voltages increase with the increase of the gas-gap length, It is worth mentioning that all the investigated gas gaps are relatively long and the photons that may reach the dielectric surface are highly attenuated to the emission of electrons from a dielectric surface [17]. Thus, equation ( 12) is valid in the presence or absence of the dielectric layer on the ground plate.…”

“…It is satisfying that the present calculated minimum threshold voltages, on the one hand, match roughly the approximate critical-voltage values based on Paschen's law. On the other hand, the calculated values of the suppression voltage V sup agree reasonably with the measured withstand voltages of the investigated gap lengths.It is worth mentioning that all the investigated gas gaps are relatively long and the photons that may reach the dielectric surface are highly attenuated to the emission of electrons from a dielectric surface[17]. Thus, equation (12) is valid in the presence or absence of the dielectric layer on the ground plate.…”