The present invention starts from an apparatus for the production of short-wave electromagnetic radiation, especially in the x-ray and gamma-ray region, by means of the interaction between accelerated charged particles, especially electrons or positrons, and a crystal lattice, with a charged-particle source for the production of a beam of energetic charged particles and with a crystal arrangement which is so arranged in the path of the charged particle radiation beam that the charged particles traverse the crystal lattice of the crystal arrangement parallel to a predetermined lattice direction ("channeling-condition").
Energetic charged particles, which impinge upon a suitable single crystal at an angle to a crystal plane or a crystal axis which is sufficiently small, are moved in an oscillatory fashion lengthwise of the pertinent crystal direction along the crystal plane or crystal axis, respectively, (so-called channeling or canalization) and emit therewith electromagnetic radiation in the forward direction, the energy whereof lies in the x-ray or gamma-radiation region, assuming corresponding mass and energy of the incident charged particles (so-called channeling- or canalization-radiation). For example, electrons with an energy between 20 and 100 MeV produce x-rays with energies between about 20 and 200 keV in monocrystalline silicon.
In the usual apparatus for the production of canalization-radiation a charged particle radiation of the smallest possible divergence is used, which impinges upon a flat single crystal parallel to a selected crystal plane or crystal axis, respectively (Appl. Phys. Lett. 57 (27), Dec. 31, 1990, 2956-2958).
In the known apparatus of the aforementioned type, therefore, the most parallel charged particle radiation possible is used, and there arises an essentially parallel beam of electromagnetic radiation. For many applications, however, appreciably convergent or divergent beams of shortwave electromagnetic radiation are required. This creates problems, since no focusing optical elements, such as lenses, are available for short-wave electromagnetic radiation.