Ion production by lasers using high–power densities in a near infrared region

Abstract

Results are presented of experiments on ion production from Ta targets using a short pulse (350-600 ps in focus) illumination with focal power densities exceeding 10 14 Wcm~2 at the wavelength of an iodine photodissociation laser (1.315 nm) and its harmonics. Strong evidence of the existence of tantalum ions with the charge state +45 near the target surface was obtained by X-ray spectroscopy methods. The particle diagnostics point to the existence of frozen high charge states (<53 + ) of Ta ions in the far expansion zone at about 2 m from the target. The measured charge state-ion energy distribution indicates the highest energy (>4 MeV) for the highest observed charge states. A tentative theoretical explanation of the observed anomalous charge state freezing phenomenon in the expanding plasma produced by a subnanosecond laser pulse is given.

Self-focusing in processes of laser generation of highly-charged and high-energy heavy ions

“…Besides the three generally accepted main ion groups~fast~F!, thermal~T!, and slow S! !~Wolowski et al., 1995;Rohlena et al, 1996!, a second fast~super-fast! FF group was proved, the existence of which coincides with the region of the maximum recorded z max .…”

The influence of an intense laser beam interaction with preformed plasma on the characteristics of emitted ion streams

“…In Figure 5a (3v, 150 J), the dependencies of peak kinetic energy of 14 ion subgroups on FP are presented that have been identified in the IC signals at various focus positions and labeled from 2 to 14. They are distributed, in principle, over three generally accepted ion groups (Wolowski et al, 1995;Rohlena et al, 1996): slow S (Hora & Kane, 1977;Häuser et al, 1992), thermal T (Hora, 1975;Borisov et al, 1992), and fast F (Sun et al, 1987;Láska et al, 2006a) (10, 7). Subgroups (Hora, 1969;Torrisi et al, 2001;Margarone et al, 2006, Láska et al, 2004a, 2004b, 2005a, clearly seen in the region of focus positions 2500 mm , FP , 0, represent a super fast (FF) ion group, which is connected with an increased intensity due to self-focusing (Láska et al, 2005c).…”

Laser-Produced Plasma Light Source Development for Extreme Ultraviolet Lithography

“…A time-of-flight (TOF) measurement combined with an electrostatic energy analyzer has been used in various applications to study laserproduced plasmas. [17][18][19] The same method has been applied to characterize the fast ions from the liquid Xe jet plasma and the experimental setup is shown in Fig. 6.…”