Experimental Research of the Diffraction and Vavilov-Cherenkov Radiation Generation in a Teflon Target M.V. Shevelev, G.A. Naumenko, A. P. Potylinsyn, Yu.A. Popov Tomsk Polytechnic University

Polarization Radiation 1.Transition Radiation 2.Diffraction Radiation 3.Cherenkov Radiation 4.Smith-Purcell Radiation 5.Parametric X-ray Radiation 6.etc. M.V. Shevelev3 RREPS 2011, September 12-16

Cherenkov Radiation M.V. Shevelev3 RREPS 2011, September Cos  ChR  1 n·n· 1.B. Bolotovskiy // Usp. Fiz. Nauk. 75,2 (1961) 2.T. Takahashi, Y. Shibata, K. Ishi et al.// Phys. Rev. E 62 (6), 8606 (2000) 3.A. Potylitsyn, G. Naumenko, Y. Popov et al. // J. Phys.: Comf. Ser. 236, (2010)

Diffraction Radiation M.V. Shevelev4 RREPS 2011, September Diffraction radiation is generated when a charged particle moves in a vacuum near a target edge. Can we detect DR from upstream edge of target?

Arrangement of TPU Experiment M.V. Shevelev5 RREPS 2011, September Extracted microtron beam parameters Electron energy6.1 MeV Average train current25 mА Beam size  5.5  5.5 mm Bunch length (rms)  2.4 mm Bunch population  5  10 8 Beam divergence 0.08  0.08 Bunches per train  10 4 RF wavelength114 mm Parabolic telescope (wave zone measurements) B.N. Kalinin, G.A. Naumenko, A.P. Potylitsyn et al., JETP Lett. 84 (3), 110 (2006) Angular resolution  = 3 о

Target & Detector M.V. Shevelev6 RREPS 2011, September o 175 mm 74 mm Teflon (PTFE) Detector DP-21M Based on wide-band antenna, high- frequency low barrier diode and preamplifier. Sensitivity 0.3 V/mW Waveband =3  30 mm n= Beyond cutoff waveguide to shield microtron RF  25 mm) Horn

Experimental Results M.V. Shevelev7 RREPS 2011, September  ChR backward transition radiation from the mirror of the telescope forward diffraction radiation Cos  ChR  1 n·n·

Experiment with real photons M.V. Shevelev8 RREPS 2011, September refracted beam Initial beam

Forward diffraction radiation is generated from the upstream edge of the dielectric target. M.V. Shevelev9 RREPS 2011, September  ChR forward diffraction radiation Why does not change Intensity of Cherenkov Radiation?

M.V. Shevelev10 RREPS 2011, September Shadowing The Coulomb field ( C.F.) is considered as beam of quasi-real photons. The second target is in the shadow of the first one. The Coulomb field is « repaired » after a distance L ~   C.F.

Arrangement for the investigation of Shadowing Samples of the measured angular distributions for different distance to the absorber M.V. Shevelev11 RREPS 2011, September 12-16

M.V. Shevelev12 In our case We should expect decrease intensity of Cherenkov radiation due to the “Shadowing” effect  ChR RREPS 2011, September 12-16

M.V. Shevelev13 Assumption Cherenkov radiation is cause of recovery electromagnetic field of relativistic charged particles for this geometry RREPS 2011, September 12-16

M.V. Shevelev14 RREPS 2011, September For this scheme only forward diffraction radiation from the upstream edge of the teflon target can be generated Proof of assumption

Experiment M.V. Shevelev15 RREPS 2011, September  ChR there is no Cherenkov radiation forward diffraction radiation

Conclusion The Forward Diffraction Radiation is experimentally observed. Cherenkov radiation is cause of recovery electromagnetic field of relativistic charged particles. M.V. Shevelev16 RREPS 2011, September 12-16

M.V. Shevelev17 CTT 2011, April 18-22

M.V. Shevelev18 RREPS 2011, September 12-16

M.V. Shevelev19 RREPS 2011, September 12-16