The IRK holds a U238 deposit that is used for neutron fluence monitoring in various collaborative cross section measurements. The mass of the deposit has been measured using three independent techniques at a total of four laboratories. Significant discrepancies have been observed between values abtained using different methods.
The primary goals of the proposed measurements are:
(a) measurement of the U238 mass by an independent method at NPL, involving associated alpha particle counting
(b) comparison of the U238(n,f), Al27(n,alpha) and Fe56(n,p) reaction cross sections in the 14 Mev range.
Measurements of the induced Na24 and Mn56 activities at NPL and IRK will be compared.