Experiments of the X1 Collaboration



   Smith Purcell




Basics of X-ray production

   Transition Radiation is emitted, when a charged particle passes the surface between two kinds of dieelectric media (i.e. surface against vaccum). The process can be understood as a polarization of the atoms by the electric field of the charged particle. Using several thin foils of the media in defined distance, interference effects become observable. This resonant transmission radiation can be used as a strong source of hard x-rays.

  Parametric X-Ray Radiation is emitted when a relativistic charged particle traverses a single crystal. The electrical field is diffracted by the bound electrons of the periodically arranged crystal atoms.

  Undulator Radiation is emitted if a relativistic electron passes a periodic transverse magnetic field. Due to the accelaration the electron emits synchrotron radiation, which is coherently added along the electrons path.

  Smith - Purcell Radiation is emitted, when a charged particle passes close to the surface of a grating. In a simple picture the emission process can be understood in the wiggling path of the induced mirror charge. In this picture a moving oscillating dipole emits the radiation.

Applications of Radiation Physics

Two types of interferometers, one for Soft X-Rays and one for Hard X-Rays were developed, allowing the measurement of the complex index of refraction of thin foils.

A novel K-edge imaging method has been developed at the Mainz Microtron MAMI aiming at a very efficient use of the transition radiation (TR) flux generated by the external 855 MeV electron beam in a foil stack.

The possibility of X-ray phase contrast imaging has been investigatated using transition radiation(TR) from a foil stack with a micro-focused 855 MeV electron beam.