Dual Gamma Neutron detection with Cs_2LiLaCl_6

摘要

Some applications, particularly in homeland security, require detection of both neutron and gamma radiation. Typically, this is accomplished with a combination of two detectors registering neutrons and gammas separately. Recently, a new scintillator, Ce doped Cs_2LiLaCl_6 (CLLC) that can provide detection of both has been investigated for gamma and neutron detection. This material is capable of providing very high energy resolution, as good as 3.4% at 662 keV (FWHM), which is better than that of Nal(Tl). Since it contains 6Li, it can also detect thermal neutrons. In the energy spectra, the full energy thermal neutron peak appears near 3 GEE MeV. Thus very effective pulse height discrimination can be achieved with this material. The CLLC emission consists of two main components: Core-to-Valence Luminescence (CVL) spanning from 220 nm to 320 nm and Ce emission found in the range of 350 to 500 nm. The former emission is of particular interest since it appears only under gamma excitation. It is also very fast, decaying with a 2 ns time constant. This provides CLLC with different temporal responses under gamma and neutron excitation and it can be used for effective pulse shape discrimination.