FIELD: nondestructive testing, measurement of thickness of walls formed by curvilinear ( cylindrical, spherical, etc ) surfaces in parts of complex asymmetrical shape. SUBSTANCE: part is advanced in direction perpendicular to fixed axis of monochromatic beam of penetrating radiation. With the aid of repeat Bragg reflection direction of motion of neutrons passed through material of part without interaction is changed. Second crystal identical by its properties to first one is used for this purpose. If it is oriented so that its working surface is rigorously parallel to plane of monochromator then only those neutrons which did not change their initial direction of advance ( after first reflection ) as result of interaction with material of part will be reflected from it. EFFECT: enhanced measurement precision, expanded range of tested objects. 6 dwg
