Characteristics study of Lil(Eu) scintillation detector towards ²⁴¹AmBe neutron source

Detector characteristics have been known to vary from one type to another, depending on the setting of working voltage, threshold or discriminator setting, the distance between the source and the detector, the amplification of the amplifier, type of radiation, radiation energy and intensity of the incoming radiation. The Lil(Eu) Scintillation detector is commonly used in BSS (Bonner Sphere Spectrometry) systems to measure neutron flux. Before being used to measure, the characteristics of Lil(Eu) detector must be known in order to obtain accurate results. The characteristics of ⁶Lil (Eu) detector towards ²⁴¹AmBe neutron source was studied by using Ludlum 2200 and BSS scaler rate-meter. A check of stability of the detector was done and the bias was less than 1 %. The response of the detector towards AmBe was linear, with the regression coefficient of nearly 1. The working voltage of the detector was on a scale of 2.1 with a threshold of 15 mV. The AmBe counting was higher above STP (Standard Temperature and Pressure). At lower altitudes, the counting of AmBe was higher due to scattering from the floor and surrounding objects. The field of thermal neutron for AmBe was ± 9.5 em and for ²⁵²Cf was ± 2.5 cm from the source center. The inverse quadratic effect of distance on the AmBe counting was linear at various BSS diameters. (author)