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The diffraction of X-rays has been studied in two-crystal interferometers, the crystals of which had equal interplanar distances and between the blocks of which a non-diffracting zone was formed as a result of ion implantation. Also the X-ray diffraction was studied in two-crystal interferometers, the interplanar distances of which were different and the non-diffracting zone between the crystals had zero width. It was shown in plane wave approximation that the Moiri: patterns should not be formed in case of former interferometers and necessarily arose with the latter type interferometers. There is some misunderstanding in the problem to which structural defects in the crystals leads the ion implantation. The authors of a number of works (BONSE, HART; BONSE et al.; SCHWUTTKE et al.; TAMURA et al.) assume that at penetration depths of implanted ions in a crystal, a nondiffracting (amorphous) zone is formed, -the crystal breaks up into two crystals having similar interplanar distances of constituent parts separated by a nondiffracting narrow gap.The others assume (AUTHIER, MONTENAY-GARESTIER; AUTHIER, SIMON; TOMITSU; WIE-TESKA; KUTT), that as a result of implantation the crystal breaks up into two parts having different interplanar distances without the non-diffracting zone.Here we shall try to show both theoretically and experimentally when and which of these assumptions is realized. Rl 61

The situations leading to the emergence of Moire patterns in X-ray interferometers and the dependence of the period of these Moire patterns on the wavelength and the order of reflection are investigated. The definite conditions of the emergence of Moire patterns are elaborated. It is demonstrated, that not all the rotations of the reflecting planes and not all the differences in interplanar spacings in interferometers lead to the formation of Moire patterns. It is shown also, that the period of Moire patterns inside the crystal does not depend on the wavelength, whereas outside the crystal, this dependence is of a periodic character. The period is reduced along with an increase in the order. &'fCCJleAORaHbI CHTYaUHH, IIpHBOAJlrrlHe K B03HHKHOBeHHlO MyapOBbIX HapTHH B peHTre-HOBCKHX HHTep@epOMeTpaX H 3aBHCHMOCTb IlepHOAa BTHX MyapOBbIX HaPTHH OT AJIkiHbI BOJIHbI H IIOpRAKa OTpalKeHIIR. Pa3pa6OTaHbI OAH03Ha4HbIe IIPH3HaKH B03HHKHOBeHMII MyapOBbIX KBPTIIH. nOKa3aH0, 4 T O He BCe IIOBOPOTbI OTpalKaIo~IIX IIJlOCKOCTe8 II He BCe pa3HOCTki MelKIIJIOCKOCTHbIX PaCCTORHH8 B HHTep@epOMeTpaX IIpHBOART K B03HHK-HOBBHHH) MyapOBbIX IcapTHH. nOKa3aHO TaHlKe, 9 T O IIepIIOA MyapOBbIX KapTHH BHyTPH KpHCTaJIJla He 3aBHCHT OT AJIHHbI BOJIHbI, a BHe KpHCTaJIJla -3Ta 3aBHCHMOCTb HMeeT nepHoAHsecmit4 xapamep. C yBenmsemeM nopmwa oTpameHMR nepHoE yMeHbmaeTcsr. l ) Mravyan 1, SU-375049 Erevan, USSR. 2, Dedicated to Prof. U. Bonse on the occasion of his 60th birthday. 24.