Harrison, H. Aryshev, A. Doucas, G. Konoplev, I.V. Lancaster, A.J. Shevelev, M. Terunuma, N. Urakawa, J. Zhang, H. JACoW Geneva, Switzerland 978-3-95450-177-9 10.18429/JACoW-IBIC2016-TUPG54 English 472-475 TUPG54 radiation detector polarization background electron Contribution to a conference proceedings 2017 2017-02 http://dx.doi.org/10.18429/JACoW-IBIC2016-TUPG54 http://jacow.org/ibic2016/papers/tupg54.pdf It is proposed to use the polarization of coherent Smith-Purcell radiation (cSPr) to distinguish between the cSPr signal and background radiation in a single-shot longitudinal bunch profile monitor. A preliminary measurement of the polarization has been carried out using a 1mm periodic metallic grating installed at the 8MeV electron accelerator LUCX, KEK (Japan). The measured degree of polarization at '=90° (300GHz) is 72.6 ±%. To make a thorough test of the theoretical model, measurements of the degree of polarization must be taken at more emission angles - equivalent to more frequencies.