Fast neutron detection with Cs2NaYCl6

In this paper we introduce a new scintillator for fast neutron and gamma ray detection, Cs₂NaYCI₆:Ce (CNYC). The material belongs to the elpasolite crystal family. The fast neutron detection is based on the ³⁵Cl(n,p)³⁵S reaction. The proton produced carries the energy proportional to the excitation energy. We show neutron energy spectra measured under continuous excitation (Cf-2S2, Am/Be) and mono-energetic excitation (from a Van de Graaff generator). The latter show clear peaks in the energy spectra. Gamma detection is also discussed. The 7% (FWHM) energy resolution was measured at 662 keV. The light yield was estimated to be lower than 10,000 photons/MeV. The material shows good proportionality, as most elpasolite scintillators. Therefore improvement in the energy resolution is expected should better light yield be achieved. Decays times and pulse shape discrimination is also discussed. The latter is critical in extracting neutron data.