6LiI(Eu) thermal neutron scintillationdetectors
Thermal neutron detection via nuclearreaction :
Since the Helium atom and the triton areboth particles with a limited range in the scintillator, a thermal neutroninteraction results in a peak in the pulse height spectrum.
Density | 4,1 g/cc |
Emission wavelength | 440 nm |
Effective decay time | 1.4 µs (neutrons and gammas) |
High neutron peak position | > 3.6 MeV |
Photoelectron yield | 30-35 % of NaI(Tl) |
6-Li enrichment | >96% |
LiI(Eu) crystal under daylight LiI(Eu) crystal under UV light
3 mm Lil(Eu) stops 90%of thermal neutrons
Rugged crystal (> 20 degrees C temperature change perhour allowed)
Excellent neutron / gamma discrimination (neutron peak > 3.6MeV)
Neutron peak resolution < 7% FWHM (PMT readout)
Pulse height spectrum showingthe presence of the thermal neutron peak relative to the Cs-137 and Co-60 interactions.The thermal neutron peak is located at 4 MeV. The spectrum shows an excellentneutron / gamma separation.
LiI(Eu) detectors can be manufactured in manydifferent geometries. Since the decay time for neutrons is essentiallydifferent from other scintillation crystals, it is possible to combine LiI(Eu)crystals to other scintillators in phoswhich geometries. By means of digitalpulse shape discrimination techniques neutron and gamma interaction can beseparated.
Photodiode readout
It is possible to read out LiI(Eu) crystals using PINphotodiodes. Such a detector is rugged and is operated at low voltage. The sameproperties for PMT readout apply
