Neutrons are important probes of matter and are crucial for an
increasing number of applications in both scientific and industrial
fields. A key element for such studies is the ability to reliably
detect neutrons. One of the most common neutron detector technology in
neutron imaging today are He-3 gas-based detectors. However, due to
the increasing scarcity of He-3, alternative technologies are
It is vital for each of these new technologies and the resulting
instrument prototypes to be tested at a dedicated facility offering
neutron irradiation. This is typically done using either standard
neutron-emitting radioactive sources or by going to a reactor beam
line. However, the latter is both highly limited in available beam time and
prohibitively cost intensive while the former typically only provides
This is where a technique called "tagging" comes in. Tagging neutrons
makes it possible to study the detector responses as function of
neutron energy even with standard radioactive sources. This data is
absolutely crucial to evaluate detector performance but is missing in "classical"
irradiations of detectors with radioactive sources.
The method of tagging high-energy or "fast" neutrons has already been
established and the corresponding setup is now located at the Source
Testing Facility (STF) at Lund University. By extending this method to
lower or "thermal" energies and by using different sources of
neutrons, the full energy range of neutrons could be made available
for in-depth tests of the neutron-response of detector prototypes --
cheap, safely and available around the clock.