In this paper, the inversion of the particle field is put forward by a function constructed for solid radioactive sources. Based on the inverse proportion between concentration and the square of the distance from the radioactive source, the concentrations surface near the radioactive source is sharp, steep and concave. The concentration surface may be convex where the nuclear radiation field is restored with sparse data by interpolation or fitting. Hence we make use of mathematical construction techniques to construct concentration function tactfully. An inversion model is established which is...
