Annular detector signal

The sensitivity of Z contrast for the detection of small clusters depends not only on the signal Z dependence, but also depends on the microscope resolution, which is governed by the probe size 6. A small cluster containing N atoms of atomic number Zi, supported on a film of effective atomic number Z2 of thickness t, will have a contrast in the annular detector signal given by... 

Elastically scattered electrons are collected by an annular detector and provide the elastic dark-field signal. A spectrometer deflects those electrons that have lost... 

Fig. 13.17 Working principle of the MEMS-based FDNMR spectrometer. The sample (S) sits within an RE excitation coU (C), which modulates the NMR signal at the mechanical resonance frequency of a resonator made up of the detector magnet (D) and sihcon beam (O). The detector magnet sits within an annular magnet (R) and the entire assembly is within the pole piece of an external field magnet (M). Detector magnet motion is measured using a fiber optic interferometer (F)...

---