Using the resonance hairpin probe and pulsed photodetachment technique as a diagnostic for negative ions in oxygen plasma
- 6 October 2010
- journal article
- research article
- Published by IOP Publishing in Plasma Sources Science and Technology
Abstract
In this work the resonance hairpin probe technique has been used for detection of photoelectrons generated during photodetachment experiments performed to determine negative ion density in an inductively coupled oxygen plasma. An investigation of the temporal development of the photoelectron population was recorded with the hairpin probe located inside the laser beam region and at various points outside the beam. Varying the external microwave frequency used to drive the probe resonator allowed the local increase in electron density resulting from photoelectrons to be determined. At a fixed probe frequency, we observed two resonance peaks in the photodetachment signal as the photoelectron density evolved as a function of time. Inside the laser beam the resonance peaks were asymmetric, the first peak rising sharply as compared with the second peak. Outside the laser beam region the peaks were symmetric. As the external frequency was tuned the resonance peaks merge at the maximum electron density. The resonance peak corresponding to maximum density outside the beam occurs at a delay of typically 1-2 mu s as compared with the centre of the beam allowing an estimate of the negative ion velocity. Using this method, negative ion densities were measured under a range of operating conditions inside and outside the beam.This publication has 33 references indexed in Scilit:
- Transport of negative hydrogen and deuterium ions in RF-driven ion sourcesPlasma Physics and Controlled Fusion, 2010
- Negative ion surface production through sputtering in hydrogen plasmaApplied Physics Letters, 2009
- Evidence forFormation by Simultaneous Double-Electron Capture during Scattering offrom a LiF(001) SurfacePhysical Review Letters, 2002
- Plasma chemistry and surface processes of negative ionsPlasma Sources Science and Technology, 2001
- Diagnostics of negative ions using probe and laser in plasmas (oxygen discharge)Vacuum, 2000
- Information from probe characteristics in negative ion containing plasmaJournal of Applied Physics, 1998
- High Fractions of Negative Ions in Grazing Scattering of Fast Oxygen Atoms from a LiF(100) SurfacePhysical Review Letters, 1995
- Negative ions in a radio-frequency oxygen plasmaPhysical Review E, 1995
- Physics and applications of charged particle beam sourcesIEEE Transactions on Plasma Science, 1991
- Negative Ions in the Positive Column of the Oxygen DischargeProceedings of the Physical Society, 1959