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首页> 外文学位 >THERMOLUMINESCENCE PROCESSES IN CALCIUM-FLUORIDE DOPED WITH CERIUM AND MANGANESE.
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THERMOLUMINESCENCE PROCESSES IN CALCIUM-FLUORIDE DOPED WITH CERIUM AND MANGANESE.

机译：掺铈和锰的氟化钙的热光致发光过程。

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摘要

Scope and Method of Study. The use of both CaF{dollar}sb2{dollar}:Ce and CaF{dollar}sb2{dollar}:Mn in thermoluminescence dosimetry (TLD) is widespread. It has been suggested that the Ce{dollar}sp{lcub}3+{rcub}{dollar} ion is acting as a sensitizer for emission from Mn{dollar}sp{lcub}2+{rcub}{dollar} ions (495 nm) during TL production in CaF{dollar}sb2{dollar}:Mn TLD materials. It has also been proposed that the Ce ions at C{dollar}sb{lcub}rm 4v{rcub}{dollar} sites in CaF{dollar}sb2{dollar}:Ce are precursors to photochromic (PC) centers in these materials during irradiation. A knowledge of the precise TL mechanism (i.e. the identification of the defects involved in the production of TL) may play an important role in understanding the dosimetric properties of this material. In this study, by application of several solid state techniques (TL, Optical Absorption, Photoluminescence and Thermally Stimulated Depolarization Currents) on selected samples of CaF{dollar}sb2{dollar}:Ce, CaF{dollar}sb2{dollar}:Mn and CaF{dollar}sb2{dollar}:Ce,Mn the validity of the above proposals have been investigated. Furthermore, from correlations among the collected data from these materials the possible mechanisms involved in TL production in these materials are suggested.; Findings and Conclusions. The presence of trace rare-earth impurities influences the TL from CaF{dollar}sb2{dollar}:Mn. This thus affects the thermal stability and sensitivity of TL from CaF{dollar}sb2{dollar}:Mn. This effect was observed in the TL from CaF{dollar}sb2{dollar} from two different batches but from the same manufacturer. The 495nm TL light from CaF{dollar}sb2{dollar} doped with high Mn concentration (3%) is certainly not a result of energy transfer from rare-earth ions (e.g. Ce) to Mn{dollar}sp{lcub}2+{rcub}{dollar} ions. Instead it might possibly be the result of F -H type recombination processes at Mn{dollar}sp{lcub}2+{rcub}{dollar}- F complex(es). The TL from CaF{dollar}sb2{dollar}:Ce is strongly influenced by the photoreversible charge transfer processes and annealing of the photochromic (PC) centers in these materials. The TL from CaF{dollar}sb2{dollar}:Mn intentionally doped with Ce is very similar to CaF{dollar}sb2{dollar}:Ce. From our observations concerning the TSDC and optical absorption we found that PC centers are not formed from dipolar C{dollar}sb{lcub}rm 4v{rcub}{dollar} centers during irradiation. A plausible alternative is that Ce{dollar}sp{lcub}3+{rcub}{dollar} ions in O{dollar}sb{lcub}rm h{rcub}{dollar} sites are the precursors to the PC centers. The presence of the Mn ions next to C{dollar}sb{lcub}rm 4v{rcub}{dollar} centers, from which energy transfer to these ions takes place during photoluminescence, can be detected by the TSDC method. The concentration calculated by using the TSDC technique does not represent the actual dipole concentration.
机译：研究范围和方法。 CaF {sal}：Ce和Cafsb2 :: Mn都在热发光剂量法（TLD）中广泛使用。有人提出Ce {dollar} sp {lcub} 3+ {rcub} {dollar}离子可作为敏化剂，用于从Mn {dollar} sp {lcub} 2+ {rcub} {dollar}离子的发射中释放（495 nm）在CaF {dol} sb2 {dollar}：Mn TLD材料中进行TL生产期间。还已经提出，CaF {dollar} sb2 {dollar}中C {dollar} sb {lcub} rm 4v {rcub} {dollar}位的Ce离子是：Ce在这些材料中是光致变色（PC）中心的前体辐射。精确的TL机制的知识（即识别TL生产中涉及的缺陷）可能在理解这种材料的剂量特性方面起重要作用。在这项研究中，通过对选定的CaF {s}} {sb2}：Ce，CaF {s} {sb2} {％}：Mn和Mn的几种样品应用几种固态技术（TL，光吸收，光致发光和热激发去极化电流）。 CaF {sb2 {dollar}：Ce，Mn已经研究了上述建议的有效性。此外，从这些材料收集的数据之间的相关性，提出了这些材料中TL生产涉及的可能机制。结论和结论。微量稀土杂质的存在会影响CaF {sb2 {dollar}：Mn的TL。因此，这影响了CaF {sb2 {dollar}：Mn中TL的热稳定性和敏感性。在来自两个不同批次但来自同一制造商的CaF {dolb} sb2 {dollar}的TL中观察到了这种效果。来自CaF {dollar} sb2 {dollar}的掺有高Mn浓度（3％）的495nm TL光肯定不是能量从稀土离子（例如Ce）转移到Mn {dollar} sp {lcub} 2+的结果。 {rcub} {dollar}离子。取而代之的可能是在Mn {dollar} sp {lcub} 2+ {rcub} {dollar} -F配合物处的F -H型重组过程的结果。 CaF {sal2}：Ce的TL受这些材料中光可逆电荷转移过程和光致变色（PC）中心退火的强烈影响。 CaF故意掺入Ce的TL与CaF sb2的TL非常相似。根据我们对TSDC和光吸收的观察，我们发现在辐照期间PC中心不是由偶极C {dolb} sb {lcub} rm 4v {rcub} {dollar}中心形成的。一个可能的替代方法是O {dolb} sb {lcub} rm h {rcub} {dollar}站点中的Ce {dollar} sp {lcub} 3+ {rcub} {dollar}离子是PC中心的前身。可以通过TSDC方法检测到在C 4中心附近存在Mn离子，在光致发光期间向这些离子进行能量转移。使用TSDC技术计算的浓度并不代表实际的偶极浓度。

著录项

  • 作者

    JASSEMNEJAD, BAHAEDDIN.;

  • 作者单位

    Oklahoma State University.;

  • 授予单位 Oklahoma State University.;
  • 学科 Physics Condensed Matter.
  • 学位 Ph.D.
  • 年度 1987
  • 页码 187 p.
  • 总页数 187
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 O49;
  • 关键词

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