Mapping neutral, ion and electron number densities within laser ablated plasma plumes


Autoria(s): Weaver, I.; Doyle, L.A.; Martin, G.W.; Riley, David; Lamb, Martin; Graham, Bill; Morrow, Thomas; Lewis, Ciaran
Data(s)

01/09/1998

Resumo

Spatially and temporally varying neutral, ion and electron number densities have been mapped out within laser ablated plasma plumes expanding into vacuum. Ablation of a magnesium target was performed using a KrF laser, 30 ns pulse duration and 248 nm wavelength. During the initial stage of plasma expansion (t <EQ 100 ns) interferometry has been used to obtain line averaged electron number densities, for laser power densities on target in the range 1.3 - 3.0 X 108 W/cm2. Later in the plasma expansion (t equals 1 microsecond(s) ) simultaneous absorption and laser induced fluorescence spectroscopy has been used to determine 3D neutral and ion number densities, for a power density equal to 6.7 X 107 W/cm2. Two distinct regions within the plume were identified. One is a fast component (approximately 106 cm-1) consisting of ions and neutrals with maximum number densities observed to be approximately 30 and 4 X 1012 cm-3 respectively, and the second consists of slow moving neutral material at a number density of up to 1015 cm-3. Additionally a Langmuir probe has been used to obtain ion and electron number densities at very late times in the plasma expansion (1 microsecond(s) <EQ t <EQ 15 microsecond(s) ). A copper target was ablated using a Nd:YAG laser, 7.5 ns duration and 532 nm (2 (omega) ) wavelength, with a power density on target equal to 6 X 108 W/cm2. Two regions within the plume with different velocities were observed. Within a fast component (approximately 3 X 106 cms-1) electron and ion number densities of the order 5 X 1012 cm-3 were observed and within the second slower component (approximately 106 cms-1) electron and ion number densities of the order 1 - 2 X 1013 cm-3 were determined.

Identificador

http://pure.qub.ac.uk/portal/en/publications/mapping-neutral-ion-and-electron-number-densities-within-laser-ablated-plasma-plumes(66347b09-9d87-49bb-88f2-3d23ae540c8a).html

http://dx.doi.org/10.1117/12.308637

Idioma(s)

eng

Direitos

info:eu-repo/semantics/restrictedAccess

Fonte

Weaver , I , Doyle , L A , Martin , G W , Riley , D , Lamb , M , Graham , B , Morrow , T & Lewis , C 1998 , Mapping neutral, ion and electron number densities within laser ablated plasma plumes . in Proceedings SPIE 3404: ALT'97 International Conference on Laser Surface Processing . vol. 3404 , pp. 341-350 , ALT 97 International Conference on Laser Surface Processing , Limoges , France , 1-1 September . DOI: 10.1117/12.308637

Tipo

contributionToPeriodical