Finite slice analysis (FINA) of sliced and velocity mapped images on a Cartesian grid.
Finite slice analysis (FINA) of sliced and velocity mapped images on a Cartesian grid.
复制标题
笛卡尔网格上切片和速度映射图像的有限切片分析 (FINA)。
DOI：
10.1063/1.4986966
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发表时间：
2017
期刊：
影响因子：
--
通讯作者：
A. Suits
中科院分区：
文献类型：
--
作者：
J. F. Thompson;C. Amarasinghe;C. Foley;N. Rombes;Z. Gao;S. Vogels;S. V. D. van de Meerakker;A. Suits
虽然时间切片成像与未切片的速度映射离子图像相比产生改进的信噪比和分辨率，但是对于在真实的实验中遇到的有限切片宽度，对于慢碎片存在分辨率和恢复强度的损失。最近，我们报告了一种新的方法，允许校正这些影响的任意切片分布的三维带电粒子云。这种有限切片分析（FinA）方法利用基函数，该基函数对给定速度分量对图像的平面外贡献进行建模，以在球面极坐标系中进行顺序减法。然而，由于需要对各向异性角分布的平面外投影进行精确建模的加权过程，原始方法遭受缓慢的处理时间。为了克服这个问题，我们提出了一种变体的方法，其中FinA方法是在圆柱坐标系（笛卡尔在图像平面），而不是一个球极坐标系中执行。被称为C-FinA，我们展示了这种方法是如何以几乎相同的方式应用的。我们将此变体与极性FinA方法进行比较，发现在最极端的情况下，处理时间（510 × 510像素图像）提高了100倍。我们还表明，虽然由此产生的速度分辨率是不太高的极版本，这种新的方法显示出上级分辨率的精细结构的微分截面。我们证明了一系列的实验和合成数据在不同的有效切片宽度的方法。
Although time-sliced imaging yields improved signal-to-noise and resolution compared with unsliced velocity mapped ion images, for finite slice widths as encountered in real experiments there is a loss of resolution and recovered intensities for the slow fragments. Recently, we reported a new approach that permits correction of these effects for an arbitrarily sliced distribution of a 3D charged particle cloud. This finite slice analysis (FinA) method utilizes basis functions that model the out-of-plane contribution of a given velocity component to the image for sequential subtraction in a spherical polar coordinate system. However, the original approach suffers from a slow processing time due to the weighting procedure needed to accurately model the out-of-plane projection of an anisotropic angular distribution. To overcome this issue we present a variant of the method in which the FinA approach is performed in a cylindrical coordinate system (Cartesian in the image plane) rather than a spherical polar coordinate system. Dubbed C-FinA, we show how this method is applied in much the same manner. We compare this variant to the polar FinA method and find that the processing time (of a 510 × 510 pixel image) in its most extreme case improves by a factor of 100. We also show that although the resulting velocity resolution is not quite as high as the polar version, this new approach shows superior resolution for fine structure in the differential cross sections. We demonstrate the method on a range of experimental and synthetic data at different effective slice widths.