Inclusion of the properties of the moderator when reconstructing the spectrum from activation detector readings

The neutron balance equation in the age approximation is proposed as an additional condition imposing restrictions on form of the neutron spectrum for a unique solution of the improper problem of reconstructing a neutron spectrum. The solution is not limited to the range of application of the age approximation and can be extended to a medium containing water. The geometric parameter and a number of other quantities that appear in the expression for the neutron spectrum are determined from the condition for best agreement between the measured and calculated activation integrals.