Development of ZnTe Powder Phosphor for Protein Crystallographic X-ray Detectors

蛋白质晶体X射线探测器用ZnTe荧光粉的研制

• 批准号: 7538474
• 负责人: Christopher J. Summers
• 金额: $ 39.56万
• 依托单位: PHOSPHORTECH
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-03-15 至 2010-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7538474
• 关键词: Air; Aluminum Oxide; Amino Acids; Area; Cereals; Chemicals; Collaborations; Communities; Compatible; Crystallography; Development; Digital Radiography; Discipline; Environment; Europe; Exhibits; Film; Financial Support; Goals; Image; Light; Marketing; Measurement; Medical; Methionine; Molecular Biology; Motivation; Output; Oxygen; Performance; Phase; Powder dose form; Problem Solving; Procedures; Process; Proteins; Public Health; Reaction Time; Roentgen Rays; Sales; Sampling; Selenium; Signal Transduction; Standards of Weights and Measures; Structure; Sulfur; Synchrotrons; System; Technology; Tellurium; Time; Today; United States National Institutes of Health; Water; Work; Zinc; absorption; base; beamline; bioimaging; capsule; concept; design; detector; experience; gadolinium sulfoxylate; improved; light emission; oxidation; physical property; prevent; scale up; seal; success; zinc selenide

DESCRIPTION (provided by applicant): We propose to continue development of a new, high-performance X-ray phosphor, based on zinc telluride (ZnTe), doped with oxygen. Currently, our phosphor is at least 3-fold brighter than present technology and further improvements are expected in Phase II. This increase in brightness will solve a major problem in the design of these detector systems. Simply stated: ZnTe:O will have a major impact on protein crystallography. Our project will be most valuable to this major field, which is extremely important to NIH. Every synchrotron beamline, assigned to structural molecular biology (there are ~20 of these), has a detector, for which NIH has already paid ~$1million. Our phosphor will improve the performance of each of these substantially. PhosphorTech Corporation (PTC) is highly experienced in this area. In 2002 we developed ZnSe:Cu,Ce, a zinc selenide (ZnSe)-based phosphor, in collaboration with Bruker-AXS Inc., for use as an X-ray screen phosphor in their chemical crystallography detector system "Apex." ZnSe:Cu,Ce has proven to be an outstanding phosphor for this application, being about 3x brighter than Gd2O2S:Tb the "standard" phosphor for CCD crystallographic detectors. ZnSe:Cu,Ce exhibits a time response (afterglow) considerably faster than Gd2O2S:Tb, which is another positive feature. Bruker AXS now dominates the chemical crystallography market in the USA and Europe, with over 85% market share. This is in part due to the remarkable success of our phosphor, and the strong acceptance of this phosphor by Bruker customers. PTC supplies this phosphor to Bruker through commercial sales and thus the contribution of PTC to chemical crystallography has been profound. We propose in this project to make an equally profound contribution to another scientific discipline structural molecular biology. However, detectors used for protein crystallography cannot use ZnSe:Cu,Ce phosphor because it contains selenium (Se). Protein crystallographers today solve their structures by "multiple energy anomalous dispersion" (MAD) phasing methods1,2. About 80% of these studies make use of Se, chemically replacing sulfur in the amino acid methionine, as the atom providing this anomalous scattering signal. Since Se in the ZnSe:Cu,Ce phosphor will manifest the same discontinuous change in its X-ray absorption spectrum as the Se in the protein crystal sample, at precisely the same X-ray energy (12,658eV), it is inappropriate for the detector used in these measurements to contain Se. ZnTe has very similar chemical and physical properties as ZnSe. The two zinc-blend structures have virtually the same lattice constant of 6.1037E, and similar band gaps (2.3eV for ZnTe; 2.7eV for ZnSe). But the absorption edges of tellurium (4,341eV, 31,814eV) are far away from the selenium edge. Thus, in addition to higher efficiency, there is a strong motivation to produce ZnTe phosphor powders that can be used to make large screens for imaging the diffraction of protein crystals. We have completely met our Phase I goals. We fabricated a ZnTe-based phosphor, ZnTe:O, that is as bright (and could potentially be brighter) than our ZnSe phosphor. We have also established fabrication procedures that seal the ZnTe:O phosphor from the outside environment, thus preventing its oxidative degradation that was the original problem for this project. The light emission of our ALD- coated ZnTe:O phosphor is now time-independent and compatible with commercial screen processes. We therefore propose, during Phase II of this project, to develop the means to synthesize larger quantities of high quality ZnTe:O phosphor powder, and optimize the large screens necessary for protein crystallography CCD detectors. ZnTe:O phosphor converting films will be most useful for protein crystallography detectors used at synchrotron beamlines, enhancing their value to NIH and to the molecular biology community as a whole. In addition, the improved performance of this phosphor also promises to have other valuable applications in biomedical imaging. PUBLIC HEALTH RELEVANCE: The proposed ZnTe:O phosphor material will have significant applications in protein crystallography detectors used at synchrotron beamlines, as well as digital radiography applications, enhancing its value to the NIH and to the molecular biology and medical communities as a whole.

描述（由申请人提供）：我们建议继续开发基于碲化锌（ZnTe）并掺杂氧的新型高性能X射线磷光体。目前，我们的荧光粉比现有技术至少亮3倍，预计在第二阶段将进一步改进。这种亮度的增加将解决这些探测器系统设计中的一个主要问题。简单地说：ZnTe：O将对蛋白质晶体学产生重大影响。我们的项目将是最有价值的这一主要领域，这是非常重要的NIH。每一条分配给结构分子生物学的同步加速器光束线（大约有20条）都有一个探测器，NIH已经为此支付了大约100万美元。我们的荧光粉将大大提高每一种材料的性能。PhosphorTech Corporation（PTC）在这方面经验丰富。2002年，我们与Bruker-AXS Inc.合作开发了ZnSe：Cu，Ce，一种硒化锌（ZnSe）基荧光粉，用作化学晶体学检测器系统“Apex. ZnSe：Cu，Ce已被证明是该应用的优秀磷光体，比CCD晶体探测器的“标准”磷光体Gd 2 O2 S：Tb亮约3倍。ZnSe：Cu，Ce表现出比Gd 2 O2 S：Tb快得多的时间响应（余辉），这是另一个积极特征。布鲁克AXS目前在美国和欧洲的化学晶体学市场占据主导地位，市场份额超过85%。这在一定程度上要归功于我们的荧光粉取得的巨大成功，以及布鲁克客户对这种荧光粉的强烈接受。PTC通过商业销售向布鲁克提供这种荧光粉，因此PTC对化学晶体学的贡献是深远的。我们建议在这个项目中做出同样深刻的贡献，另一个科学学科结构分子生物学。然而，用于蛋白质晶体学的检测器不能使用ZnSe：Cu，Ce磷光体，因为其含有硒（Se）。如今，蛋白质晶体学家通过“多能量异常色散”（MAD）定相方法解决了它们的结构。大约80%的这些研究利用硒，化学取代硫的氨基酸蛋氨酸，作为原子提供这种异常散射信号。由于ZnSe：Cu，Ce磷光体中的Se将在其X射线吸收光谱中表现出与蛋白质晶体样品中的Se相同的不连续变化，在精确相同的X射线能量（12，658 eV）下，这些测量中使用的检测器不适合包含Se。ZnTe具有与ZnSe非常相似的化学和物理性质。这两种锌共混物结构具有几乎相同的晶格常数6.1037E，和相似的带隙（ZnTe为2.3eV; ZnSe为2.7eV）。而碲的吸收边（4，341 eV和31，814 eV）远离硒的吸收边。因此，除了更高的效率之外，还存在生产ZnTe磷光体粉末的强烈动机，所述ZnTe磷光体粉末可用于制造用于对蛋白质晶体的衍射进行成像的大屏幕。我们完全实现了第一阶段的目标。我们制造了一种基于ZnTe的磷光体，ZnTe：O，它与我们的ZnSe磷光体一样亮（并且可能更亮）。我们还建立了将ZnTe：O磷光体与外部环境密封的制造程序，从而防止其氧化降解，这是该项目的原始问题。我们的ALD涂层ZnTe：O磷光体的光发射现在与时间无关，并与商业屏幕工艺兼容。因此，我们建议，在该项目的第二阶段，开发的手段来合成大量的高品质ZnTe：O荧光粉，并优化蛋白质晶体学CCD探测器所需的大屏幕。ZnTe：O磷光体转换膜将是最有用的蛋白质晶体学检测器在同步加速器光束线，提高其价值，美国国立卫生研究院和整个分子生物学社区。此外，这种磷光体的性能改进也有望在生物医学成像中具有其他有价值的应用。 公共卫生相关性：所提出的ZnTe：O磷光体材料将在同步加速器光束线上使用的蛋白质晶体学检测器以及数字X射线照相应用中具有重要应用，从而提高其对NIH以及整个分子生物学和医学界的价值。