Application of rare earth doped apatite to radioluminography

为了研制辐射能量传感器，尝试将类似磷灰石化合物的氯磷酸锶晶体和氯磷酸钡晶体应用于放射发光法的荧光粉。掺铕、钆的氯磷酸锶和氯磷酸钡晶体经X射线辐照后，均表现出明亮的光致发光。结果表明，掺Eu或Gd的氯磷酸锶的光致发光强度高于掺Eu或Gd的氯磷酸钡，掺Eu或Gd的氯磷酸钡在紫外光照射下呈现暗光致发光。然而，Eu或Gd掺杂的氯磷酸锶在紫外线照射或可见光照射后表现出PSL。此外，热释光和ESR信号，由于电子捕获的电子在紫外线或可见光照射后观察到的Eu或Gd掺杂的氯磷酸锶类似于Eu或Gd掺杂的氯磷酸锶在X射线照射后。这些结果表明，在比氯磷酸锶（基质晶体）的带隙能量低的能量辐照下，在掺Eu或Gd的氯磷酸锶中形成了电子陷阱中心，即掺Eu或Gd的氯磷酸锶可用作辐射能量传感器。

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.