[en] The purpose of this article is to characterize the atomic nucleus used as a target in hadron-nucleus collision experiments. The atomic nucleus can be treated as a lens-shaped ''slab'' of nuclear matter. Such ''slab'' should be characterized by the nuclear matter layer thickness at any impact parameter, by its average thickness, and by its maximal thickness. Parameters characterizing atomic nuclei as targets are given for the elements: ₆¹²C, ₇¹⁴N, ₈¹⁶O, ₉¹⁹F, ₁₀²⁰Ne, ₁₃²⁷Al, ₁₄²⁸Si, ₁₆³²S, ₁₈⁴⁰Ar, ₂₄⁵²Cr, ₂₆⁵⁴Fe, ₂₇⁵⁹Co, ₂₉⁶⁴Cu, ₃₀⁶⁵Zn, ₃₂⁷³Ge, ₃₅⁸⁰Br, ₄₇¹⁰⁰Ag, ₅₃¹²⁷I, ₅₄¹³¹Xe, ₇₃¹⁸¹Ta, ₇₄¹⁸⁴W, ₇₉¹⁹⁷Au, ₈₂²⁰⁷Pb, ₉₂--²³⁸U