Angular distribution of X-ray radiation by 500 MeV electrons in a tungsten crystal

X-rays generated by a 500 MeV electron beam of the Tomsk synchrotron in a tungsten single crystal with a mosaic factor less than 80" has been studied theoretically and experimentally. The tungsten crystal was a block with sizes 1.7 x 10 x 15 mm(3) aligned with the (1 1 1) plane at the Bragg angle theta(B) approximate to 45degrees to the electron beam axis. The emitted photons were detected at an angle of 2theta(B) with respect to the electron beam. The emitted angular distributions for the (2 2 2) and (4 4 4) orders have been measured and compared with predictions of the developed theoretical model. This model takes the contribution of parametric X-radiation (PXR) and diffracted transition radiation (DTR) generated by relativistic electrons from in-surface of a crystalline target as well as an influence of an interference between PXR and DTR emission mechanisms into account. The obtained results show the important contribution of DTR to the measured emission yield. (C) 2002 Elsevier Science B.V. All rights reserved.