RBS Instrumentation: Sample Chamber

The main sample chamber components are a stage, one or more detectors,a beam entrance, and the vacuum system. The chamber can be as simple asa flange with a sample and a single energy dispersive spectrometer attached.

More typically, the samples mount on a five-axis goniometer, which isconvenient for loading many samples into the vacuum system and analyzingthem sequentially. The goniometer can also tilt and rotate the samples.Comparing spectra obtained at different incident and exit beam angles providesbetter characterization of sample composition as a function of depth. Randomlytilting and rotating a sample relative to the incident beam avoids variationsin the spectrum that arise because the incident beam travels down a channelin the sample's crystal structure. Two surface barrier detectors (one normal angle, one grazing exit), are included in a typical RBS sample chamber.

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