An Absolute Atomic Scattering Factor for Germanium Obtained by Anomalous Transmission in a Bicrystal

Abstract

Using the newly developed method of dynamical interference between anomalously transmitted waves in a crystal containing a non-diffracting zone1 , we have measured the real part of the atomic scattering factor for germanium at the value of sin θ/λ corresponding to the 220 Bragg reflection. The result, f0 = 23.79 ± 0.08 electron units is in excellent agreement with values obtained in perfect crystal intensity measurements 2,3 and from triple crystal rocking curve studies 4,5 but significantly differs from the value obtained using Pendellösung fringes 3. Finally, we seek to assess the reliability of each method by comparison with the corresponding results for silicon, concluding that the error probably lies in the Pendellösung result.