Neutron detectors based on gas-discharge tubes filled with 3He have a high thermal neutron registration efficiency and are not sensitive to others ionizing radiation. But the main disadvantage of such detectors is the high cost of a very rare isotope 3He.
One of the effective elements for the registration of thermal neutrons is the isotope of lithium 6Li, which nature contamination is much more (about 7.5% of the total lithium) than 3He-content. LiI:Eu scintillation material enriched with 6Li has a good neutron/gamma discrimination (more than 0.8).
The purpose of this work was to develop a new design of a thermal neutron detector, based on a LiI:Eu scintillation material.
Due to possibility of easy installation a new detector instead of 3He a tubular design of detector was used. The detector was made by applying a crystalline thin layer of LiI:Eu on the inner wall of an ampoule. The registration efficiency of thermal neutrons obtained by a tubular detector with a natural isotopic composition of Li with a total thickness of 3.2 mm deposited is 23.47%. Improving of detector efficiency may achieved by increasing the thickness of the scintillation layer and/or additional enrichment of the material with the 6Li.