The paper describes an experimental study of the characteristics of a pulse-modulated radiofrequency(RF)discharge sustained at low pressures,typical of the operating modes of RF gridded ion sources.The motivation for ...The paper describes an experimental study of the characteristics of a pulse-modulated radiofrequency(RF)discharge sustained at low pressures,typical of the operating modes of RF gridded ion sources.The motivation for the study is the question of whether the RF pulsemodulated mode can increase the efficiency of the ion source.The ion current values extracted from an RF inductive ion source operating in continuous and pulse-modulated modes were compared.The experimental data were also compared with the parameter calculations based on a0D numerical model of the discharge.The measurements showed that the pulse-modulated operation mode of the RF ion source had a noticeable advantage when the power of the RF generator was 140 W or lower.However,as the generator power increased,the advantage was lost because the pulse-modulated operation mode,having a higher RF power instant value,entered the region of existence sooner than the continuous mode,where the ion production cost begins to grow with RF power.展开更多
The efficiency of radio-frequency(RF)power absorption,RF magnetic field structure and plasma parameters were measured in cylindrical inductive RF plasma sources 20 cm in diameter and 22,32,53 cm in length with a low v...The efficiency of radio-frequency(RF)power absorption,RF magnetic field structure and plasma parameters were measured in cylindrical inductive RF plasma sources 20 cm in diameter and 22,32,53 cm in length with a low value external magnetic field.The experiments were carried out in argon at pressures of 13-140 m Pa.The RF power supply changed from 200 W to 800 W.The spiral antenna was used for sustaining the discharge.It was shown that efficiency of RF power absorption depended nonlinearly on the external magnetic field values.At maximal values of the RF power absorption efficiency,the axial distributions of longitudinal Bzand azimuthal Bφcomponents of RF magnetic field manifested the formation of the partially standing wave with a half wavelength close to 8 cm.At the same conditions,the axial dependence of the radial RF magnetic field component Brdiffered drastically.It was concluded that the Bz and Bφamplitudes were largely determined by the RF field of Trivelpiece-Gould wave,while Br amplitude represented the radial RF field of the helicon wave.展开更多
文摘The paper describes an experimental study of the characteristics of a pulse-modulated radiofrequency(RF)discharge sustained at low pressures,typical of the operating modes of RF gridded ion sources.The motivation for the study is the question of whether the RF pulsemodulated mode can increase the efficiency of the ion source.The ion current values extracted from an RF inductive ion source operating in continuous and pulse-modulated modes were compared.The experimental data were also compared with the parameter calculations based on a0D numerical model of the discharge.The measurements showed that the pulse-modulated operation mode of the RF ion source had a noticeable advantage when the power of the RF generator was 140 W or lower.However,as the generator power increased,the advantage was lost because the pulse-modulated operation mode,having a higher RF power instant value,entered the region of existence sooner than the continuous mode,where the ion production cost begins to grow with RF power.
文摘The efficiency of radio-frequency(RF)power absorption,RF magnetic field structure and plasma parameters were measured in cylindrical inductive RF plasma sources 20 cm in diameter and 22,32,53 cm in length with a low value external magnetic field.The experiments were carried out in argon at pressures of 13-140 m Pa.The RF power supply changed from 200 W to 800 W.The spiral antenna was used for sustaining the discharge.It was shown that efficiency of RF power absorption depended nonlinearly on the external magnetic field values.At maximal values of the RF power absorption efficiency,the axial distributions of longitudinal Bzand azimuthal Bφcomponents of RF magnetic field manifested the formation of the partially standing wave with a half wavelength close to 8 cm.At the same conditions,the axial dependence of the radial RF magnetic field component Brdiffered drastically.It was concluded that the Bz and Bφamplitudes were largely determined by the RF field of Trivelpiece-Gould wave,while Br amplitude represented the radial RF field of the helicon wave.
