Gamma-ray solid laser: ion-optical system for fasthigh-quality focusing of powerful non-paraxial ion beams of largeformat enriched with excited nuclei

Abstract

An ion-optical system (IOS) for fast high-quality focusing of powerful paraxial ion beams of large format is suggested. Such beams could be enriched in excited short-lived (10^-4-10^-6 s) laser-active nuclei (ELAN). To increase the beam power, ions are collected from the visible surface (10-10⁴ cm²) of an intermediate target (converter). The full converter surface is enhanced by a factor of 10²-10⁴ by a special micro-relief and achieves 10³-10⁷ m². The toms containing ELAN are created in the converter by a powerful radiation source using neutrons, γ quanta, charged particles, etc. Those ELAN atoms are emitted from the converter surface and selectively ionized by a dye laser just above the surface. Using a specially chosen emitter (converter) shape, a paraxial ion beam is formed. This is due to the micro-relief structure of the emitter surface, its high-quality orientation, and cylindrical (instead of spherical) ion optics. In the vicinity of an active medium (AM) for a gamma-ray laser, the ions are decelerated so that they can penetrate only into 1-3 outer layers of the host matrix, e.g., diamond. This makes heating of the AM by the ion beam negligible in comparison to self-heating due to internal conversion. Analytical and numerical estimation of the IOS aberrations have shown that the compression of the ion beam exceeds10⁵-10⁶, and that a considerable part (10%) of the ELAN reach the AM in a time as short as10^-7 s. This ensures the rapid and controllable deposition of ELAN into an AM within a gamma-laser system based on existing techniques without using nuclear explosions.