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Martinelli, G.

Paper Title Page
TUPD033 Fabrication of Crystals for Channelling of Particles in Accelerators 1497
 
  • A. Mazzolari, S. Baricordi, V. Guidi, G. Martinelli, D. Vincenzi
    UNIFE, Ferrara
 
  Channelling in bent crystals is used for beam extraction, focusing, collimation in accelerators machines, studies related to emission of coherent electromagnetic radiation and other topics. Distinctive features of performance increase is the availability of new techniques to manufacture the crystals within which channeling takes place. We propose a method to fabricate crystals through micromachining techniques, i.e., photolithography and anisotropic chemical etching. Patterning of a Si wafer with silicon nitride allows selective erosion of uncovered areas along specific atomic planes, resulting in a technique to dice Si wafers to the needed dimensions solely through chemical methods. Thus, it results in no damage to the crystal quality due to the dicing process. As was demonstrated by electron microscopy investigation, the crystal exhibits ultra flat lateral surfaces and simultaneously no amorphous layer at the entry face of the crystal with respect to the beam. The crystals were positively tested at the external line H8 of the SPS with 400 GeV protons for investigation on axial channeling and on single and multiple volume reflection experiments by the H8-RD22 collaboration.