Neutron-induced reactions

Virtually all measurements of neutron-induced reactions interesting for nuclear astrophysics are performed either applying the time-of-flight (TOF) technique or the activation technique. The most important reactions are neutron captures (n,γ), neutron-induced alpha emission (n,α) and neutron-induced fission (n,f).

A typical TOF setup consists of a pulsed neutron source, a sample positioned at a given flight path and a time-resolving detection system for the reaction products.
schematic TOF setup

Usually, the TOF-spectrum begins with the γ-flash resulting from interactions of the primary beam particles with the neutron production target. The gammas traveling at the speed of light arrive first at the detector systems. Later the first, fastest neutrons arrive and even later slower neutrons.
schematic TOF spectrum

A typical activation setup consists of a continuous neutron source, a sample positioned very close to the neutron source and a separate setup to detect to decay of freshly produced, radioactive nuclei.
schematic activation setup


FRANZ at Uni Frankfurt
DANCE at Los Alamos