Planar channeling experiments with electrons at the 855 MeV Mainz Microtron MAMI

Planar channeling has been studied for silicon single crystals at a beam energy of 855 MeV at the Mainz Microtron MAMI. Complex channeling patterns were observed from which the crystal orientation can unambiguously be determined. Photon spectra at (1 0 0), (1 1 0) and (1 1 1) planar channeling were recorded with a 10″ × 10″ NaI detector. The planar (1 1 0) channeling process has been studied as function of the crystal thickness in the range between 7.9 and 270 μm from which a dechanneling length of 18.0 μm and the thickness dependent rechanneling lengths were deduced, employing solutions of the Fokker-Planck equation. A signal derived from high energy bremsstrahlung exhibits a characteristic length of (32 ± 4) μm which is tentatively interpreted as the occupation length of the lowest quantum states in the planar potential. Prospects are discussed to exploit channeling of high energy electrons in periodically bent silicon single crystals for production of radiation in the hundreds keV to multi MeV range.