Purpose. The technology allows growing large-sized high-quality single crystals, which significantly reduces the cost of production (detectors) compared to the methods used to grow small-sized single crystals (the Bridgman and Stockbarger methods).
Technical properties. The “Growth” type installation is a cylindrical pressure chamber consisting of two half-cases (upper and lower). The lower half-case is movable, the heat unit (furnace shaft) is assembled in it, the upper half-case is fixed. A crystal holder with ignition is mounted in the center on top of the upper half-case on special seals. The crystal holder rotates and moves up and down. Type of grown material – CsI (Na), CsI pure. Crystal (blank) parameters: – crystal diameter – 470 mm; – crystal height during growth – 10 mm; – height (max from seed to unloading without front) – 110 mm; – crystal front height (after MSR) – 30 mm; – max crystal weight – 120 kg. Characteristics of the obtained material: – activator (Na) concentration in the crystal – 1.5-2*10-3 mass %; – energy resolution for 25×30 samples – 6.2% and lower; – light output for 25×30 samples – 4% and higher.
Application area. Growing single crystals, instrument making.
Advantages. The technology allows growing large-sized single crystals, which significantly reduces the cost of the source material for the manufacture of detectors, and therefore the cost of the final product, and also allows obtaining large-sized detectors.
Technical and economic effect. The approximate production capacity is 7.5 tons per year. The introduction of the technology will reduce the cost of the source material for the manufacture of detectors, which will lead to a decrease in the cost of the final product, and will also contribute to the creation of additional jobs.
Description. The technological process of growing CsI(Na) single crystals on the “Growth” type installations consists of extracting the single crystal from the melt for single crystal ignition. The technological process is carried out as follows. First, the thermal chamber for growing and the units of the growth installation are prepared for growing (checking the operability of the equipment) and the tightness of the vacuum seals of the growth furnace are checked. Then the raw material is loaded into the crucible and the half-cases are joined. Before starting the growing, the growth furnace is additionally checked for tightness and the presence of moisture. After melting the raw material and bringing the melt temperature to the required one, the growth furnace is checked again for vacuum, after which the growing begins, which consists of growing the single crystal to the required final diameter and then to the required final height. Then the single crystal is cooled to room temperature in the chamber of the growth furnace. The cooled crystal is transported to the processing area.