Experimental study of charge state distribution from KrF and ruby laser-produced plasmas

Abstract

The detailed angular charge distributions of the asymptotic plasma produced from carbon and aluminum targets by UV and visible laser pulses in the intensity range of 1011–1013 W cm−2 and pulselength range of 1–20 nsec have been measured using a single shot electrodynamic charge analyzer. The observed variation of average charge state as a function of velocity was determined from measurement and has been found to be approximately linear with no apparent dependence on angle of observation. For similar irradiation conditions, shorter-wavelength radiation produces lower final charge states, as expected, from the higher interaction density in the initial laser produced plasma leading to enhanced recombination in the early stages of expansion of the plasma. The characteristics of the angular charge distribution can be qualitatively explained by considering the flow of the source plasma mapping different regions of the focal spot into different angles, relative to the target normal, in the expanding plasma.

Particle characterization for the evaluation of the181mTa excitation yield in millijoule laser induced plasmas

“…In [33,34], the angular distributions of the slow ions measured with similar probes are found to follow a cos n θ power law with n equal to 6.3 ± 1.0. The ion integrated flux (assuming a mean ionic charge Z equal to 10) is calculated using this power law adjusted to the Langmuir probe data.…”

Study of angular dependences of ion component parameters in CO2-laser-produced plasma

“…The total ion current was measured at 308 cm distance from the target using tripleelectrode grid-less collector, where two electrodes were used for ion beam extraction. The extraction voltage on collector U ext = − (12)(13)(14)(15) kV provided the saturation of the measured current signal. The data of measurements on the ion collector and ion analyser were registered using digital oscilloscope LeCroy 9450 and then post-processed by original software.…”

“…Systematic study of the ion component charge state, energy and angular distributions of a plasma created from carbon and aluminium targets by radiation of KrF hang ruby lasers was performed in [13,14]. Arrays of plasma calorimeters and charge collectors were used to map the angular distribution of energy and ion velocity in the expanding plasma.…”

Guiding and confinement of a laser produced plasma by a curved magnetic field

“…10,12 The total number of ions that were guided by the 2.2 kG magnetic field was estimated to be 2ϫ10 14 assuming a parabolic distribution radially and that the average charge state of the ions is 1. The angular distribution of the ion number was estimated to have an angular dependence of ϳ cos 8 ().…”