  The primary reference instruments for neutron fluence measurements used at
the Physikalisch-Technische Bundesanstalt (PTB) are based on the primary
standard for neutron measurements which is the differential neutron-proton
scattering cross section. Such instruments require considerable effort for
their operation and analysis. Therefore, routine measurements are carried out
using a transfer instrument to facilitate the efficient provision of services
to customers. A series of measurements was conducted to compare the transfer
device to the primary reference instruments and ensure the traceability of
neutron fluence measurements. This resulted in an improved characterization of
the instrument and new analysis procedures.
