Laser plasma is generated in 1GW iodine photodissociation laser (λ = 1.315 ㎛) of which output beam is focused on the surface of metal targets(Al, Cu, Ti, and Mo). Theoretical models of laser plasma are suggested and the experiments on soft x-ray generation and diffraction are conducted.
Prior to the experiments an extensive computer simulation is carried out on continuous soft x-ray emission from the laser plasma. Bremsstrahlung is a smoothly peaked function of wavelength, decreasing toward longer wavelength and in very short wavelength region it falls off exponentially. Recombination radiation on the contrary has a step-wise behavior with wavelength corresponding to the limit of the spectral series after Lyman, Balmer, Paschen, etc.
The intensity of transmitted x-ray for Mo laser plasma is measured for the various thickness of Al foils. The angular distribution of soft x-ray generated is determined by using x-ray film. The intensity falls off systematically with increasing polar angle from the incident laser axis.
The size of Al laser plasma is measured by x-ray pinhole camera. The sizes of laser plasma emitting soft x-rays and long wavelengths are found to be 440 ㎛ and 1300 ㎛, respectively. The different sizes according to the kinds of x-ray filter indicate the spatial distribution of plasma temperature.
X-ray diffraction pattern is observed with Mica crystal by x-ray diffraction camera. The lattice spacing of (002) plane of Mica is identified as 19.8 Å from the x-ray analysis. The wavelength of diffracted x-ray is found to be 15.9 Å(±0.7 Å).
