Angle-resolved absolute out-of-band radiation studies of a tin-based laser-produced plasma source

Abstract

Out-of-band radiation emitted from an extreme ultraviolet laser-produced plasma, formed on a solid tin target, was measured over several angles between 25° and 85° with respect to the target normal for six energy bands between 200 and 1000nm. The optical and target system was rotated with respect to the detector and the intensity of the radiation was measured using an absolutely calibrated filter/photodiode combination. The emission was dominated by radiation in the 214nm band. A cosine function fitted to the angular distribution of the total radiation yielded an exponent of 0.23±0.02.

Ion emission in collisions between two laser-produced plasmas

“…energy distribution is observed only in the direction normal to the target and the angle-resolved integrated flux can be fitted by a cos n function [27] similar to the single plasma plume case [28]. It is also evident from figure 4 that the ion signal, in the colliding plasma case, splits into two distinct peaks, labeled P1 and P2, when the Faraday cup is moved to angles between 5° and 30° either side of the target normal.…”

Simplified one-dimensional calculation of 13.5 nm emission in a tin plasma including radiation transport

“…I, satellite emission is not included as dielectronic recombination was not calculated in the modelling since the bulk of the satellite emission contributes only to the out-of-band spectra and has minimum effect on the in-band CE. 31,32 Spatially-dependent laser absorption is from inverse bremsstrahlung 33 and is modelled as 20%, the default value in MED103. 20 Two surveys are presented which independently vary power density and pulse duration.…”

Steady-State and Time-Dependent LPP Modeling

“…Maximium 2% in-band emission is at approximately 40 eV. Note that the 7.4% range gives a simple estimate of out-of-band emission (OOB), known to reduce mirror lifetime because of thermal loading (Morris et al, 2007). The results have been compared to experiment (White et al, 2005), where it is seen ( Figure 7) that the long wavelength edge is matched at lower electron temperatures (and thus lower ion stages within the plasma) and the short wavelength edge matched at higher electron temperatures (and thus higher ion stages within the plasma).…”