Sergeeva, D.Yu. Strikhanov, M.N. Tishchenko, A.A. JACoW Geneva, Switzerland 978-3-95450-177-9 10.18429/JACoW-IBIC2016-WEPG62 English 793-795 WEPG62 radiation polarization factory target diagnostics Contribution to a conference proceedings 2017 2017-02 http://dx.doi.org/10.18429/JACoW-IBIC2016-WEPG62 http://jacow.org/ibic2016/papers/wepg62.pdf Polarization radiation, which includes diffraction radiation (DR), transition radiation (TR), Smith-Purcell radiation, and others, can be a good instrument for beam diagnostics. All information about the beam size is contained in the so-called form-factor of the beam. The form-factor represents the sum of two parts corresponding to the coherent and incoherent radiation*. Contrary to the general opinion the incoherent part does not always equal unity*, **. In this report we give theoretical description of the incoherent and coherent parts of the form-factor both for Gaussian and uniform distribution of the ultrarelativistic particles in the bunch*, ***. The theory constructed describes also the case of beam skimming the target, which leads to mixing of DR and TR***. We show that the incoherent part depends on the transversal size of the beam, and dependence differs for different distributions. The role of the incoherent part of the form-factor of the bunch for different parameters is discussed.