BIOLOGICAL APPLICATIONS OF A COMPUTER CONTROLLED ANALYTICAL ELECTRON MICROSCOPE

电子能量损失谱是用一种 由后置光谱仪组成的Gatan并行探测器系统 四极透镜，YAG闪烁体，光纤耦合， 光电二极管阵列和相关的电子设备。 检测器 测量量子效率并发现其接近于1， 从而比传统方法提高了大约1000倍。 光谱的常规连续记录。 能量分辨率为 在100 keV束能量下达到约1.5 eV。 光谱与 可以在100毫秒内记录良好的计数统计， 从而允许执行实时EELS。 初步数据 已经从一些氟类似物中获得， 神经递质，表明这些化合物可能是 在具有生物学意义的浓度下， 积分时间为1秒。 还可以监测 辐射损伤和质量损失的实时观测， 有机物中氮、氧和氟核边缘的衰变 分子。

Electron energy loss spectra have been obtained by means of a Gatan parallel detector system consisting of Post-spectrometer Quadrupole lenses, a YAG scintillator, fiber-optic coupling, a photodiode array and associated electronics. The detector quantum efficiency was measured and found to be close to unity, giving approximately a 1000-fold improvement over the conventional serial recording of spectra. An energy resolution of about 1.5 eV was achieved at 100 keV beam energy. Spectra with good counting statistics could be recorded in 100 milliseconds, thus allowing real-time EELS to be performed. Preliminary data have been obtained from some fluorine analogs of neurotransmitters, indicating that such compounds might be detectable at biologically meaningful concentrations with an integration time of 1 second. It has also been possible to monitor radiation damage and mass loss in real-time by observing the decay of nitrogen, oxygen and fluorine core edges in organic molecules.