The experimental investigation of X-ray flow diffracted in the crystal

The energy flow of diffracted X-rays in perfect crystals has been investigated experimentally in Bragg case diffraction. It has been shown that besides the diffracted beam two more beams appear, which in case $\mu t=15$ protrude from the frontal side of the crystal. The appearance of these beams is due to penatration of such waves into the crystal, which have a small absorption coefficient and deviate from the right Bragg angle.