Purpose. The technology allows to obtain LiI:Eu2+ single crystals for detecting slow neutrons. Single crystals are used as a working element of detectors applied at nuclear power plants. The technology was developed to obtain LiI:Eu2+ single crystals (lithium iodide activated by europium (Eu2+)), which are used to detect slow neutrons.
Technical properties. The technology allows to obtain LiI:Eu2+ single crystals with a diameter of 12-15 mm and a length of up to 80 mm. The capacity of one process line is 50 single crystals per year.
Scope. Inorganic substance technology, single crystal growth.
Advantages. The use of europium (III) oxide instead of europium (II) iodide as an activating additive reduces the cost of the product.
Technical and economic effect. The technology allows to obtain single crystals of the neutron detector – lithium iodide activated by europium – at a reduced cost. The use of detectors to monitor the operation of nuclear power plants helps to improve the ecology of the environment.
Description. A sealed ampoule with lithium iodide is opened in a dry box and LiI is poured into a quartz ampoule, the inner surface of which is covered with carbon. A weighed amount of europium (III) oxide is added to lithium iodide, which corresponds to its concentration of 0.06 wt.%. A rubber tube is put on the open end of the quartz ampoule, the ampoule is evacuated and the rubber tube is clamped. Single crystals are grown using the Bridgman method in a two-zone growth furnace, the temperature on the diaphragm is 470 °C, the lowering speed of the container is 1.5 mm / hour. After complete crystallization of the melt in the container, cooling is carried out automatically at about 4 C / hour.