A target assembly composed of multiple target tiles bonded in an array to a backing plate of another material. The edges of the tile within the interior of the array are formed with complementary beveled edges to form slanted gaps between the tiles. The gaps may slant at an angle of between 10.degree. and 55.degree., preferably 15.degree. and 45.degree., with respect to the target normal. The facing sides of tiles may be roughened by bead blasting, for both perpendicular and sloping gaps. The area of the backing plate underlying the gap may be roughened or may coated or overlain with a region of the material of the target, for both perpendicular and sloping gaps.