A pnCCD-based, fast direct single electron imaging camera for TEM and STEM
A pnCCD-based, fast direct single electron imaging camera for TEM and STEM
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DOI：
10.1088/1748-0221/11/04/p04006
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发表时间：
2016-04
影响因子：
1.3
通讯作者：
H. Ryll;M. Simson;Robert Hartmann;P. Holl;M. Huth;S. Ihle;Yukihito Kondo;P. Kotula;A. Liebel;K. Müller-Caspary;Andreas Rosenauer;R. Sagawa;J. Schmidt;H. Soltau;L. Strüder
中科院分区：
文献类型：
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作者：
H. Ryll;M. Simson;Robert Hartmann;P. Holl;M. Huth;S. Ihle;Yukihito Kondo;P. Kotula;A. Liebel;K. Müller-Caspary;Andreas Rosenauer;R. Sagawa;J. Schmidt;H. Soltau;L. Strüder
我们报告一种新的相机，是基于pnCCD传感器的应用在扫描透射电子显微镜。新兴的显微镜技术要求改进探测器的读出速率，灵敏度和辐射硬度，特别是在扫描模式。pnCCD是满足这些要求的2D成像传感器。其固有的辐射硬度允许直接检测电子。pnCCD以每秒1，150帧的速率读出，图像面积为264 x 264像素。在合并或窗口模式下，读出速率几乎线性增加，例如在4×合并（264 x 66像素）下达到每秒4000帧。由于探测器的高灵敏度，可以区分能量从300 keV到5 keV的单个电子。在扫描透射电子显微镜中的三个应用突出显示pnCCD满足实验要求，特别是快速记录的2D图像。在第一次应用中，在70 s内记录了65536个二维衍射图案。重建对应于各种衍射峰强度的STEM图像。对于第二种应用，显微镜以类洛伦兹模式操作。在不到37秒的时间内对256 x 256个样本点的区域中的磁畴进行成像，总共生成65536张图像，每张图像具有264 x 132像素。由于二维图像提供的信息，不仅可以确定磁场的幅度，而且可以确定磁场的方向。在第三个应用中，记录半导体纳米结构的毫秒图像以确定样品中的晶格应变。与以前使用的相机系统相比，可以实现测量时间的200倍加速。
We report on a new camera that is based on a pnCCD sensor for applications in scanning transmission electron microscopy. Emerging new microscopy techniques demand improved detectors with regards to readout rate, sensitivity and radiation hardness, especially in scanning mode. The pnCCD is a 2D imaging sensor that meets these requirements. Its intrinsic radiation hardness permits direct detection of electrons. The pnCCD is read out at a rate of 1,150 frames per second with an image area of 264 x 264 pixel. In binning or windowing modes, the readout rate is increased almost linearly, for example to 4000 frames per second at 4× binning (264 x 66 pixel). Single electrons with energies from 300 keV down to 5 keV can be distinguished due to the high sensitivity of the detector. Three applications in scanning transmission electron microscopy are highlighted to demonstrate that the pnCCD satisfies experimental requirements, especially fast recording of 2D images. In the first application, 65536 2D diffraction patterns were recorded in 70 s. STEM images corresponding to intensities of various diffraction peaks were reconstructed. For the second application, the microscope was operated in a Lorentz-like mode. Magnetic domains were imaged in an area of 256 x 256 sample points in less than 37 seconds for a total of 65536 images each with 264 x 132 pixels. Due to information provided by the two-dimensional images, not only the amplitude but also the direction of the magnetic field could be determined. In the third application, millisecond images of a semiconductor nanostructure were recorded to determine the lattice strain in the sample. A speed-up in measurement time by a factor of 200 could be achieved compared to a previously used camera system.