Brink H A, Barfels M M G, Burgner R P, Edwards B N
Gatan Research and Development, 5933 Coronado Lane, Pleasanton, CA 94588, USA.
Ultramicroscopy. 2003 Sep;96(3-4):367-84. doi: 10.1016/S0304-3991(03)00102-5.
A high-energy resolution post-column spectrometer for the purpose of electron energy loss spectroscopy (EELS) and energy-filtered TEM in combination with a monochromated (S)TEM is presented. The prism aberrations were corrected up to fourth order using multipole elements improving the electron optical energy resolution and increasing the acceptance of the spectrometer for a combination of object area and collection angles. Electronics supplying the prism, drift tube, high-tension reference and critical lenses have been newly designed such that, in combination with the new electron optics, a sub-50 meV energy resolution has been realized, a 10-fold improvement over past post-column spectrometer designs. The first system has been installed on a 200 kV monochromated TEM at the Delft University of Technology. Total system energy resolution of sub-100 meV has been demonstrated. For a 1s exposure the resolution degraded to 110 meV as a result of noise. No further degradation in energy resolution was measured for exposures up to 1 min at 120 kV. Spectral resolution measurements, performed on the pi* peak of the BN K-edge, demonstrated a 350 meV (FWHM) peak width at 200 kV. This measure is predominantly determined by the natural line width of the BN K-edge.
本文介绍了一种用于电子能量损失谱（EELS）和能量过滤透射电子显微镜（TEM）的高能量分辨率柱后光谱仪，它与单色（S）TEM相结合。使用多极元件将棱镜像差校正到四阶，提高了电子光学能量分辨率，并增加了光谱仪对物区和收集角组合的接受度。为棱镜、漂移管、高压参考和临界透镜供电的电子设备已重新设计，与新的电子光学系统相结合，实现了低于50 meV的能量分辨率，比过去的柱后光谱仪设计提高了10倍。第一个系统已安装在代尔夫特理工大学的200 kV单色TEM上。已证明总系统能量分辨率低于100 meV。对于1 s的曝光，由于噪声，分辨率降至110 meV。在120 kV下曝光长达1 min时，未测量到能量分辨率的进一步下降。在BN K边的π*峰上进行的光谱分辨率测量表明，在200 kV时峰宽为350 meV（半高宽）。该测量主要由BN K边的自然线宽决定。
