LLC “Lyumpeks”, Pereslavl-Zalessky, Russia:

E. I. Boev, Technical Director, e-mail: ei.boev@yandex.ru

National Research Nuclear University “MEPhI” (Moscow Engineering Physics Institute), Moscow, Russia:
M. A. Glagoleva, Assistant Professor, e-mail: mag905@yandex.ru

For the purpose of quality improvement and increasing of yield enhancement of image converter tubes, there was developed the synthesis technology of luminophore Gd₂O₂S:Tb (KFL-544 (КФЛ-544)) with average crystal size of 0.6–0.8 μm, and its output was organized for replacement of both luminophore KS-525 (КС-525) (ZnS:Cu, Al) (insufficiently stable with the temperature of 400 °С) and luminophore R-43 (Р-43) (Gd₂O₂S:Tb) (currently imported). In comparison with ZnS, the higher thermal resistance of Gd₂O₂S allows to increase the heat treatment temperature of screens with luminophore in vacuum to the range of 450–500 °С, which increases the yield enhancement of image converter tube screens. Tests of screens with luminophore KFL-544 and R-43 have shown that the screens with luminophore KFL-544 with close chromaticity coordinates are brighter than the screens with luminophore R-43. At the same time, luminophore KFL-544 allows to obtain a high-quality uniform coating without defects. Image converter tubes EPM 215G-00-11 (ЭПМ 215Г-00-11) with luminophores KFL-544 and R-43 were manufactured. Measurement results have shown that the light output of the screens with luminophores R-43 and KFL-544 is 3.5–4 and 6–6.5 cd/W; resolving limit of image converter tubes is 63.2–66.6 and 66.6–70.1 str/mm; resolving limit of screen centre is 150–180 and 170–190 str/mm respectively. There was offered the luminescent method of qualitative assessment of Eu impurity content in the Gd₂O₃ batch, meant for the Gd₂O₂S:Tb synthesis by comparison of self-activated zone and Eu zone intensities in the researched batch and check sample. Positive results with Gd₂O₂S:Tb synthesis may be obtained with use of Gd₂O₃ batches in case if Eu zone intensity is not more than 20% of self-activated zone intensity which should be not more than 80% in comparison with check sample.

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