Dual Laser Plasma Photoabsorption Studies Of Gadolinium In The Extreme Ultraviolet Region Paddy Hayden National Centre for Plasma Science & Technology (NCPST) / School of Physical Sciences, Dublin City University
Talk outline Introduction/motivation Dual Laser Plasma (DLP) Photoabsorption Previous Results for Sn Gd I absorption spectrum Summary
Talk outline Introduction/motivation Dual Laser Plasma (DLP) Photoabsorption Previous Results for Sn Gd I absorption spectrum Summary
Sn UTA (Unresolved Transition Array) R. Cowan, The Theory of Atomic Structure and Spectra, University of California Press (1981) 5 Sn VII 5 Sn XI 1 12 14 16 18 2 1 12 14 16 18 2 5 Sn VIII 5 Sn XII 1 12 14 16 18 2 1 12 14 16 18 2 5 Sn IX 5 Sn XIII 1 12 14 16 18 2 1 12 14 16 18 2 5 Sn X 5 Sn XIV 1 12 14 16 18 2 1 12 14 16 18 2 blue 4d-4f, red 4d-4p, green 4d-5p sum of all three is the black dashed
Sn Inband 1 Sn VII 4 2 Sn XI -1 13.35 13.4 13.45 13.5 13.55 13.6 13.65 13.7.2.1 13.35 13.4 13.45 13.5 13.55 13.6 13.65 13.7 4 2 Sn IX 13.35 13.4 13.45 13.5 13.55 13.6 13.65 13.7 2 1 Sn X 13.35 13.4 13.45 13.5 13.55 13.6 13.65 13.7 13.35 13.4 13.45 13.5 13.55 13.6 13.65 13.7 4 2 Sn XII 13.35 13.4 13.45 13.5 13.55 13.6 13.65 13.7 15 1 Sn XIII 5 13.35 13.4 13.45 13.5 13.55 13.6 13.65 13.7 5 Sn XIV 13.35 13.4 13.45 13.5 13.55 13.6 13.65 13.7 Assume we can not discriminated amongst the UTA, so Intrinsic Conversion Efficiency is the ratio of inband to out-of-band
Ratio of inband to broadband Sn Inband Efficiency 35 3 Broadband Inband 25 Sn XII is the brightest inband (2% bandwidth @13.5 nm) 2 15 1 5 7 8 9 1 11 12 13 14 Ion stage.7.6 Sn XIV is the most efficient (6 %) Sn XII 42% efficiency.5.4.3.2.1 7 8 9 1 11 12 13 14 Ion stage
Gd UTA 1 1 5 Gd XXI 5 Gd XXV 1 4 6 8 1 12 14 16 1 4 6 8 1 12 14 16 5 Gd XXII 5 Gd XXVI 1 4 6 8 1 12 14 16 1 4 6 8 1 12 14 16 5 Gd XXIII 5 Gd XXVII 1 4 6 8 1 12 14 16 1 4 6 8 1 12 14 16 5 Gd XXIV 5 Gd XXVIII 4 6 8 1 12 14 16 4 6 8 1 12 14 16 blue 4d-4f, red 4d-4p sum of all is the black dashed
Ratio of inband to broadband Gd Inband Efficiency 25 2 Broadband Inband Gd XXIV is the brightest inband (.6% bandwidth @ 6.78 nm) 15 1 5 21 22 23 24 25 26 27 28 Ion stage Gd XXII is the most efficient (5%) Gd XXIV 3% efficiency.6.5.4.3.2.1 21 22 23 24 25 26 27 28 Ion stage
Ratio of inband to broadband Gd Inband Efficiency Only 4 upper configurations included and only two inband Scaling factors fixed 25 2 15 Broadband Inband To give a better idea: Shift mirror to peak of UTA, (7.6 nm) keeping a.6 % bandwidth Gd XXIII is the brightest inband. 1 5 21 22 23 24 25 26 27 28 Ion stage.2 Gd XXIII is the most efficient (16 %) Gd XXII (46%) if a 2% bandwidth is used.15.1.5 21 22 23 24 25 26 27 28 Ion stage
Power Densities Required Sn Gd ~1.2 x 1 11 Wcm -2 for Nd:YAG [P. Hayden et al., J. Appl. Phys. 99, 9332 (26)] ~1 x 1 1 Wcm -2 for CO 2 [S. Fujioka, et al., Appl. Phys. Lett. 92, 24152 (28)] ~4 x 1 12 Wcm -2 for Nd:YAG [T. Cummins, et al., Appl. Phys. Lett. 1, 61118 (212)] This corresponds to ~ 4x 1 11 Wcm -2 for CO 2 To get this: x3.8 laser energy x.52 spotsize x.27 pulse width For the case where the laser energy is increased: 3.8 x 16%(max. Gd efficiency)=6.8%, similar to the Sn case, but half the number of photons
Talk outline Introduction/motivation Dual Laser Plasma (DLP) Photoabsorption Previous Results for Sn Gd I absorption spectrum Summary
L. Gaynor, PhD Thesis, UCD (27) DLP Photoabsorption J. T. Costello, et al, Phys. Scr. T34, 77-92 (1991)
DLP Photoabsorption Record I 1 Relative absorption give by ln(i /I 1 ) Gd target Cylindrical Lens W target Optical axis Dt, from ns to ms Plano-convex Lens
Talk outline Introduction/motivation Dual Laser Plasma (DLP) Photoabsorption Previous Results for Sn Gd I absorption spectrum Summary
Previous Results for Sn M. Lysaght, et al., Phys. Rev. A 72, 1452 (25) Absolute 4d εf shape resonance cross sections (9 12 Mb) determined by comparison to relativistic time dependent local density approximation (RTDLDA) calculations [D. A. Liberman, A. Zangwill, Comp. Phys. Comm. 32, 75 (1984)], for Sn and a range of similar elements. the measured cross sections appear to be smaller than predicted especially at the peak cross section reproduced the cross section profile extremely well once the energies were shifted by a constant amount 1 1 ev
Talk outline Introduction/motivation Dual Laser Plasma (DLP) Photoabsorption Previous Results for Sn Gd I absorption spectrum Summary
Relative Absorption DLP Photoabsorption for Gd I J. P. Connerade and M. Pantelouris, J. Phys. B: At. Mol. Phys. 17, L173 (1984) Connerade Connerade DLP DLP Gd I Gd I Gd II Gd III 65 7 75 8 85 9 Wavelength (Å) Mainly 4f εg shape resonance, along with 4d εf and 5p εd
(Mb) DLP Photoabsorption for Gd I 7 6 5 Connerade DLP Gd I Gd II Gd III 4 3 2 1 65 7 75 8 85 9 Wavelength (Å) Mainly 4f εg shape resonance, along with 4d εf and 5p εd
Talk outline Introduction/motivation Dual Laser Plasma (DLP) Photoabsorption Previous Results for Sn Gd I absorption spectrum Summary
Summary Similar emission f values for Sn and Gd Ratio of inband /out-of-band higher for Sn (42% vs 3%) 6.x nm, define x (ratio up to 16%) Maximum bandwidth (up to 46% if 2% bandwidth) Only f values, actual emission will depend on ionisation balance, level populations, radiation transport, etc. High power densities needed for Gd One way, by using x3.8 laser energy, should give similar intensities as achieved by Sn today, half the number of photons though. Cross sections due to shape resonance in lower ion stages similar for Sn and Gd ~7 12 Mb. Improved experimental and calculated data to be published soon
Acknowledgements DCU: J. Costello, T. Kelly, and C. Fallon UCD: G. O Sullivan, P. Dunne, E. Sokell, F. O Reilly, C. O Gorman, T. Cummins, Bowen Li... TCD: J. Lunney, I. Tobin Funding: Science Foundation Ireland 7/IN.1/I1771, ERASMUS MUNDUS - EMJD -EXTATIC - FPA 212-33 - EACEA programme