Collimation of plasma-produced x-rays by spherical crystals: Ray-tracing simulations and experimental results

Ray-tracing simulations, validated by experimental results, demonstrate tha t high intensity collimated x-ray beams can be produced from an isotropic x -ray source. A spherically bent mica crystal was used to collimate and mono chromatize x rays emitted by a femtosecond laser-produced plasma. The resul t is a short pulse x-ray beam with a high degree of collimation (less than 1 mrad divergence), good spectral resolution (10(-2) < Delta lambda/lambda <10(-4)), and tunability over a wide spectral range. The role of the experi mental parameters in the resulting beam divergence is thoroughly analyzed b y ray-tracing modeling. These simulations are validated by test experiments . The ray-tracing calculations define a set of boundaries in the experiment al parameters, which will guarantee the achievement of collimated beams bet ter than 1 mrad in further experiments. (C) 1999 American Institute of Phys ics. [S0034-6748(99)01303-9].