Light pulse shapes in liquid scintillators originating from gamma-rays and neutrons

Liquid scintillators loaded with boron-10 or lithium-6 are capable to detect gamma rays, fast neutrons and also thermal neutrons. One of the popular methods applied in order to distinguish events originating from different particles is pulse shape discrimination (PSD). The previously presented study of boron-10 loaded liquid scintillators showed different discrimination performance using the PSD method in scintillators such as BC523A, BC523A2, EJ339A2 and EJ309B5. It triggered a further study of light pulse shapes in these scintillators originating from events related to gamma rays and fast and thermal neutrons. The light pulse shapes were measured using single photon method and added to the 2-dimensional n/gamma discrimination data as the third parameter. Next, the recorded light pulse was gated using energy and PSD information to extract pulses characteristic of the only one kind of particles. Finally, the analysis of the light pulse shapes was performed with multi-exponential fits to experimental data and calculation of decay time constants and intensities of components. The results were compared with the liquid scintillators BC501A, EJ301 and EJ309, not sensitive to thermal neutrons.