X-Ray Crystal Spectroscopy of Sub-picosecond Laser-Produced Plasmas beyond 50 keV*1

Abstract

The interaction of a sub-picosecond (sub-ps) laser with a high-Z target produces a hard x-ray continuum, but to our knowledge no high-resolution study of the line emission is known. We present here crystal spectroscopy as a tool for the observation of energetic line x-radiation from a sub-ps laser-produced plasma. Reflection properties of flat and bent crystals for x-ray spectroscopy are analyzed theoretically for both the Bragg and the Laue geometries and optimized for a crystal spectroscopy of hard (ú50 keV) x-radiation. The crystal setup is optimized for spectroscopic applications with regard to high throughput and spectral resolution. The characteristic tantalum Ka,b-and La,b-line emissions from a sub-ps laser-produced plasma is observed for the first time. A resolving power of about 450 is achieved which is much higher than that for comparable absorption filter techniques (E/DE É 15). ᭧ 1997 Academic Press

Laser produced X-ray source in the 10-60 keV range at 1 kHz. Modified irradiation schemes in order to reach medical imaging quality

“…Along with the main pulses, delivered at 10Hz, this laser system also produces prepulses (with a contrast of 10-3 -10-4 ), which create a pre-plasma for the main pulse to interact with. To characterize the process, the xray spectra have been studied through crystal spectroscopy [2] and photon counting techniques [3]. The imaging capability has also been investigated mainly using conventional medical image plates or streak cameras [1].…”