Compact NE213 neutron spectrometer with high energy resolution for fusion applications

Neutron spectrometry is a tool for obtaining important information on the fuel ion composition, velocity distribution and temperature of fusion plasmas. A compact NE213 liquid scintillator, fully characterized at Physikalisch-Technische Bundesanstalt, was installed and operated at the Joint European Torus (JET) during two experimental campaigns (C8-2002 and trace tritium experiment-TTE 2003). The results show that this system can operate in a real fusion experiment as a neutron (1.5 MeV<En<20 MeV) spectrometer with good energy resolution (ΔE/E<4% at En=2.5 MeV and ΔE/E<2% at En=14 MeV). First measurements performed under different plasma scenarios, including trace tritium experiments, are presented. The analysis of the pulse height data was carried out using a newly developed method based on maximum entropy unfolding. The results indicate that this efficient, inexpensive, and compact scintillator is suitable for use as a broadband spectrometer in large fusion devices (JET and the International Thermonucle...