A. Egbert
B. Mader
B. N. Chichkov
J. P. Girardeau-Montaut

Compact high-repetition rate femtosecond laser driven hard-x-ray source

Advances in Laboratory-Based X-Ray Sources and Optics
8. Juli
Seattle
2002
Type: Konferenzbeitrag
Abstract
An alternative way to generate ultrashort hard-x-rays is to use low-intensity femtosecond laser pulses in combination with a specially designed {\textquotedbl}x-ray tube{\textquotedbl}. The femtosecond laser pulses induce photoemission of electrons from a photocathode. The electron bunch is then accelerated towards a high-Z target material by applying an external high-voltage electric field. Hard-x-rays are produced by bremsstrahlung of accelerated electrons and characteristic line emission. In contrast to the existing laser-plasma x-ray sources which require high-power laser systems, for the realization of this novel x-ray source, low-energy, compact, high-repetition rate, commercially available femtosecond lasers can be used. In this presentation we report on our progress in the development and investigation of a femtosecond laser-driven x-ray tube. We demonstrate the influence of relevant parameters (e.g. laser fluence, wavelength, accelerating voltage) on the electron and hard-x-ray generation efficiency using different photocathode and x-ray target materials. The laser-driven hard-x-ray source is characterized in terms of brilliance, spectral properties, and pulse duration. The latter is performed using an ultrafast x-ray streak camera in combination with a laser-triggered accumulation system.