Updated State Primary Special Standard of Units of Neutron Flux Density and Neutron Fluence for Nuclear-Physics Facilities

The design of updated sources of neutrons from the composition of the State Primary Special Standard of units of neutron flux density and neutron fluence for nuclear-physics facilities, GET 51–17, whose upper bound of the reproduction range is raised several-fold as a result of the use of a better neutron generator – NG-10M, is described. The principles and methods of reproducing the neutron flux density and neutron fluence units on a reference standard and evaluating accuracy are described. The metrological characteristics of the updated reference standard, which were obtained in the course of its study and during primary certification, are presented and the sources of error of the reference standard are described in detail.