Enhanced ?-? discrimination in co-doped LaBr3:Ce

LaBr₃:Ce crystal scintillator can be co-doped with various alkaline earth metals to improve light output and energy resolution of the basic scintillator. Another benefit is improvement of alpha/gamma discrimination via pulse shape analysis. LaBr₃:Ce contains a low level of actinium contamination, which produces an alpha particle background. This background is difficult to discriminate from gamma rays. Conversely, the addition of co-dopant into the crystal makes the alpha response much easier to distinguish. LaBr₃:Ce,Sr, for example, produces a second, longer decay component in the scintillation pulse when excited by radiation. The amplitude of this second decay component changes in response to a gamma ray versus a heavy charged particle. The change in pulse shape is used to eliminate the alpha background and enable detection of neutron reaction products.