Brilliant x-ray radiation from a low emittance 855 MeV electron beam

Electron storage rings as synchrotron radiation sources are presently the most powerful x-ray sources in the energy range between 0.53 keV, the "water window" for microscopy of biological molecules, and 33.16 keV, the K-edge of iodine for a possible coronary angiography. However, with the advent of modern electron accelerators delivering high current low emittance electron beams with energies up to a few GeV it was realized that they may present also attractive sources of intense x rays. In this contribution we report on the investigation of resonant transition radiation in the x-ray region (XTR), and parametric x-ray radiation (PXR) as such x-ray sources. The experiments have been performed with the low emittance (3 it nm rad) 855 MeV electron beam of the Mainz Microtron MAMI....DFG (SFB 201) and BMFT under contract MZ 565.DFG (SFB 201) and BMFT under contract MZ 565.Approved for public release; distribution is unlimited