A time of flight spectrometer for double differential neutron cross section measurements.

The time of flight neutron spectrometry technique by associated alpha particle method for double differential neutron cross section measurements using a D-T neutron generator was implemented. An stilbene scintillation detector was used as the main detector and it was located outside the irradiation room obtaining a 3.40 m flight path. For the associated alpha particle detection a thin plastic NE-102 scintillator was used, as well as, two NE-213 scintillation detectors and a long counter for neutron flux monitoring. An automatic system for neutron cone screening in coincidence to the alpha particle cone was developed. A very good n-gamma discrimination, signal to noise ratio and a 1.7 ns of temporal resolution was achieved. This work was partially supported by the CUB/01/005 IAEA project.