Directly exposed electron-detectors for electron energy-loss spectroscopy

Abstract: This thesis investigates the possibilities of using planar silicon-devices such as the photodiode array and the charge-coupled device (CCD) as directly exposed electron-detectors for electron energy-loss spectroscopy. The aim is to achieve an acceptable performance at low signal intensities, enabling single electron detection. We investigate three different detectors: a photodiode array, a front-illuminated CCD and a back-thinned CCD. The detectors are attached to a transmission electron microscope and they are exposed to 100 keV electrons.The performance is determined in terms of the noise performance, the ability of resolving spatial features and the occurrence of radiation damage.The conclusions are that the photodiode array did not resolve low intensities due to a high readout noise level and the electron beam introduced damages. The front-illuminated CCD did resolve single electrons but it suffered from radiation damage as well. The back-thinned CCD did not show any signs of damage and it did resolve single electrons. However, the signal-to-noise ratio was limited by the effect of the elastic scattering of the incident electrons within the silicon.We propose a solution on how to improve the signal-to-noise ratio of the back-thinned CCD by lowering the electron energy.