Well-characterised neutron fields are a prerequisite for the investigation of neutron detectors. Partly in collaboration with external partners, the PTB neutron metrology group makes available for other users neutron reference fields covering the full energy range from thermal to 200 MeV. The specification of the neutron fluence in these beams is traceable to primary standard cross sections.
Nolte, R., Allie, M., Bottger, R., Brooks, F., Buffler, A., Dangendorf, V., Friedrich, H., Guldbakke, S., Klein, H., Meulders, J.-P., Schlegel, D., Schuhmacher, H., & Smit, F. (2004). Quasi-monoenergetic neutron reference fields in the energy range from thermal to 200 MeV. Radiation Protection Dosimetry, 110(1-4), 97-102. https://doi.org/10.1093/rpd/nch195 (Original work published 2004)