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首页> 外文学位 >Three-dimensional positron annihilation momentum measurement technique applied to measure oxygen-atom defects in 6H silicon carbide.
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Three-dimensional positron annihilation momentum measurement technique applied to measure oxygen-atom defects in 6H silicon carbide.

机译：三维正电子an没动量测量技术用于测量6H碳化硅中的氧原子缺陷。

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摘要

A three-dimensional Positron Annihilation Spectroscopy System (3DPASS) capable to simultaneously measure three-dimensional electron-positron (e--e+) momentum densities measuring photons derived from e--e+ annihilation events was designed and characterized. 3DPASS simultaneously collects a single data set of correlated energies and positions for two coincident annihilation photons using solid-state double-sided strip detectors (DSSD). Positions of photons were determined using an interpolation method which measures a figure-of-merit proportional to the areas of transient charges induced on both charge collection strips directly adjacent to the charge collection strips interacting with the annihilation photons. The subpixel resolution was measured for both double-sided strip detectors (DSSD) and quantified using a new method modeled after a Gaussian point-spread function with a circular aperture. Error associated with location interpolation within an intrinsic pixel in each of the DSSDs, the subpixel resolution, was on the order of +/- 0.20 mm (this represents one-standard deviation). The subpixel resolution achieved was less than one twenty-fifth of the 25-mm2 square area of an intrinsic pixel created by the intersection of the DSSDs' orthogonal charge collection strips. The 2D ACAR and CDBAR response for single-crystal copper and 6H silicon carbide (6H SiC) was compared with results in the literature. Two additional samples of 6H SiC were irradiated with 24 MeV O+ ions, one annealed and one un-annealed, and measured using 3DPASS. Three-dimensional momentum distributions with correlated energies and coincident annihilation photons' positions were presented for all three 6H SiC samples. 3DPASS was used for the first experimental measurement of the structure of oxygen defects in bulk 6H SiC.
机译：设计并表征了能够同时测量三维电子-正电子（e-e +）动量密度的三维正电子An没光谱系统（3DPASS），该电子正电子An灭能谱测量了从e-e + ni灭事件衍生的光子。 3DPASS使用固态双面剥离检测器（DSSD）同时收集了两个一致的an灭光子的相关能量和位置的单个数据集。使用插值法确定光子的位置，该插值法测量的品质因数与在与hil灭光子相互作用的直接与电荷收集条相邻的两个电荷收集条上感应的瞬态电荷的面积成比例。对两个双面条形检测器（DSSD）都测量了亚像素分辨率，并使用一种新方法进行了量化，该新方法是根据具有圆孔的高斯点扩展函数建模的。与每个DSSD的内部像素（子像素分辨率）中的位置插值相关的误差约为+/- 0.20 mm（这表示一个标准偏差）。所获得的子像素分辨率小于DSSD正交电荷收集条的相交所产生的本征像素的25平方毫米平方面积的二十五分之一。将单晶铜和6H碳化硅（6H SiC）的2D ACAR和CDBAR响应与文献中的结果进行了比较。再用24 MeV O +离子辐照另外两个6H SiC样品，将其退火，一个未退火，然后使用3DPASS进行测量。给出了所有三个6H SiC样品的具有相关能量和重合correlat没光子位置的三维动量分布。 3DPASS用于批量6H SiC中氧缺陷结构的首次实验测量。

著录项

  • 作者

    Williams, Christopher S.;

  • 作者单位

    Air Force Institute of Technology.;

  • 授予单位 Air Force Institute of Technology.;
  • 学科 Physics Nuclear.;Physics Radiation.
  • 学位 Ph.D.
  • 年度 2010
  • 页码 198 p.
  • 总页数 198
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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