X射线诱导BaFCl:Eu2+光激励发光过程的新观察

本文研究了ＢａＦＣｌ：Ｅｕ＾２＾＋光激励发光（ＰＳＬ）对Ｘ射线剂量的响应关系，光激励发光的衰减规律，以及色心的形成与转型。除了简单的Ｆ心之外，我们还发现了Ｆ心的缔合中心，它们的吸收带位于７００－９５０ｎｍ。连续光激励Ｆ心时，光激励发光呈指数型衰减，而光激励发光（ＴＳＬ）也显现类似的衰减规律。光激励Ｆ缔合中心时，伴随着光激励发光还可能有一些无辐射跃迁过程的产生，例如色心的分解，转型和解离电子的再捕获

SOME NEW OBSERVATION ON THE PROCESS OF THE PHOTOSTIMULATED LUMINESCENCE(PSL) OF X-IRRADIATED BaFCl: Eu2+

X-ray dose dependence of PSL, PSL decay, color centers formation and interconversion of BaFCl:Eu2+ have been studied. In addition to the previously known simple F-centers there were found aggregated F centers having absorption bands in the region 700-950nm. Continuously optical stimulation into F-center band and aggregated F centers band would result in logarithmical and hyperbolical decay process of PSL respectively. The thermally stimulated lumineasence (TSL) of pure or Eu doped BaFCl show the similar decay trends. There might happen some nonradiative processes accompaning with the PSL and TSL as the crystals are shmulated into aggregated F centers bands, such as decomposition, interconversion and electron-retrapping of ionized color centers. The relative content of Eu3+/Eu2+ and the ESR spectra Fbis subest was supported by the National Natural Science Foundation orChina.* Prcsentaddress: Department of Materials Physics, Beijing University of Science and Technology,Beijing 100083, China.of Eu2+ in BaFCl: Eu prior and subsequent to X-irradiation practically remain unchanged. The PSL response-dose range of lightly X-irradiated BaFCl: Eu2+ exhibits a linear relationship. But for the heavily X-irradiated BaFCl: Eu crystals its PSL-dose response and PSL decay curves of latter period deviate from linearity. That may arise from the interconversion of various F centers and competitive retrapping of electrons by different ionized F centers and other positive centers.