System nonlinearity analysis
As described in section “Energy calibration”, HyperLab proposes an energy calibration model, where the slowly varying nonlinear and frequently changing linear parts are separated.
Nonlinearity curve
The nonlinearity of a measurement system at a specific point of time is characterized by a so called nonlinearity curve. This describes the system's deviation from the linear calibration line, as shown in the picture below.
The figure shows the nonlinearity curve of HyperLab's Nonlinearity module for several calibration measurements.
The curve itself is depicted by a red line, its ±1σ limit with blue lines, while the data points are from the centroid shift of the fitted peaks.
The green triangles (at 600ch and 2800ch) show the points where the curve crosses the zero nonlinearity value.
In HyperLab, the system nonlinearity curve always uses the channel-channel scale, as with these units the nonlinearity characteristics are supposed to be slowly varying with the time.
The calculated nonlinearity may be used for several purposes:
 
 
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