Primary standardization and Monte Carlo modeling of (Am + Np) by means of a 4π(PC)-γ coincidence counting system.

The procedure followed by the Nuclear Metrology Laboratory (LMN) at the IPEN for the primary standardization of a (Am + Np) solution, in secular equilibrium, is described. The measurement was carried out in a 4π(PC) (α,β)-γ coincidence system. The total activity per unit mass of the solution was determined by the extrapolation technique, using a software coincidence counting systsem.