Search

The influence of metal grids on the characteristics of particles extracted from a plasma was investigated in the course of development of the laser-plasma ion source for heavy-ion injectors. Plasma was produced by irradiating carbon and tungsten targets by СО2 laser pulses with a flux density of ~1011 W/cm2. The influence of grids was estimated by measuring the signals from a detector−analyzer of ion energy spectra, the total ion current, and the ion-beam emittance behind the extraction system. A significant effect of the geometrical parameters of the grid and the ion mass number on the ion-beam characteristics was observed. The results we obtained can be qualitatively explained by the sputtering of the grid material by a high-energy particle "head" of the ion beam and by the subsequent effect of the produced atomic-gas "cloud" on the ion-beam transmission. [ABSTRACT FROM AUTHOR]

A computer code is developed for processing primary images obtained in the pepper-pot emittance measurement technique, which makes it possible to estimate emittance in a single measurement. The code uses a pepper-pot mask image on a scintillator screen obtained by means of laser plasma radiation. This image is used to find positions of holes of the mask and its rotation angle. The pepper-pot technique is applied to measure emittance of a carbon ion beam extracted from the laser-produced plasma, which is generated by CO2 laser pulses at the focal power density on the target of about 1011 W/cm2. Some results of image processing and calculation of the emittance are presented. [ABSTRACT FROM AUTHOR]

Experiments on the irradiation of a carbon target with СО-laser pulses in the free-running mode at a radiation-flux density of 1.3 × 10 W/cm and the time-of-flight technique for measuring the characteristics of the plasma ion component are described. The characteristics of the ion component of plasma that expands along the normal to the target and the statistical spread of the mean values were obtained. As a result of the measurements, the energy spectra of the plasma expansion and the partial ion currents at a chosen distance of the plasma drift from the target were reconstructed. The high time resolution of this technique made it possible to reconstruct the escape times of individual groups of ions from a heated region on the scale of the duration of the heating laser pulse. [ABSTRACT FROM AUTHOR]

The design of a pulse-periodic СО laser oscillator that operates at a high level of the specific energy deposition into a self-sustained discharge is described. The laser is intended for generating pulses with a high-density radiation flux in a laser-plasma generator of multiply charged ions at the Institute of Theoretical and Experimental Physics (ITEP). The results of investigations of the spatiotemporal and energy characteristics of laser output radiation in a wide range of the discharge excitation level and the mixture composition are presented. The optimal conditions are determined under which the oscillator provides an output energy of >10 J in a pulse with a duration of ~28 ns and a record specific peak radiation power of 190 MW per liter of the active volume of a CO: N: He mixture. The high quality of the spatial characteristics was confirmed in measurements of the radial energy-density distribution in the far-field zone, whose characteristic size is close to the diffraction limit. [ABSTRACT FROM AUTHOR]

The design of a laser oscillator with a stabilized frequency composition and a stabilized intensity of output radiation is described. The oscillator's basic component is a TEA CO module pumped by a self-maintained discharge and operating in a repetition-rate mode at a frequency of up to 3 Hz. A circuit for the formation of a self-maintained homogeneous discharge in the working volume of a CO + N + He mixture at atmospheric pressure is the basic component of the gas-discharge module. This circuit is based on the generation of a high-voltage pulse with a special profile, which provides high-reliability excitation of a discharge and pulse-to-pulse reproducibility of the discharge characteristics. The use of a hybrid circuit in the optical oscillator allows selection of a single longitudinal mode in the output radiation spectrum, thus eliminating undesirable interference phenomena, which lead to instability of the instantaneous values of the radiation intensity. During the development of the oscillator, the optimal operating parameters of the hybrid circuit were obtained, which ensure the high quality and reproducibility of the spatiotemporal and energy parameters of laser radiation. [ABSTRACT FROM AUTHOR]

As a result of above investigations it was established that: [ABSTRACT FROM AUTHOR]