Application of rare earth doped apatite to radioluminography

1995 Fiscal Year Final Research Report Summary

• Project/Area Number: 06650960
• Research Category: Grant-in-Aid for General Scientific Research (C)
• Allocation Type: Single-year Grants
• Research Field: 無機工業化学
• Research Institution: Niigata University
• Principal Investigator: OHTA Masatoshi Niigata University, 工学部, 助教授 (60092673)
• Project Period (FY): 1994 – 1995
• Keywords: Radioluminography / radiation sensor / apatite compound / ESR / barium chlorophosphate / strontium chlorophosphate / rare earth / photostimulated luminescence phosphor

Research Abstract

Strontium chlorophosphate crystal and barium chlorophosphate crystal which are analogous apatite compounds, were attempted to apply to a luminescence phosphor for radioluminography, in order to develop an energy sensor of radiation. Strontium chlorophosphate crystal and barium chlorophosphate crystal doped with europium ion or gadolinium ion exhibited a bright photostimulated luminescence (PSL) after X-ray irradiation. The PSL intensity was higher in Eu- or Gd-doped strontium chlorophosphate than in Eu- or Gd-doped barium chlorophosphate.
Eu- or Gd-doped barium chlorophosphate exhibited dark PSL after ultraviolet irradiation. However, Eu- or Gd-doped strontium chlorophosphate exhibited PSL after ultraviolet irradiation or visible ray irradiation. Furthermore, thermoluminescence and ESR signal due to electron captured with electron trap was observed in Eu- or Gd-doped strontium chlorophosphate after ultraviolet or visible ray irradiation in analogy with Eu- or Gd-doped strontium chlorophosphate after X-ray irradiation. These results suggest that electron trap center is formed in Eu- or Gd-doped strontium chlorophosphate irradiated with lower energy ray than band gap energy of strontium chlorophosphate (host crystal), that is, Eu- or Gd-doped strontium chlorophosphate is available for an energy sensor of radiation.