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The Sum and IMAX are calculated by the firmware. TMIT is provided by the BMP IOC and sent to the firmware as described earlier. The TMIT value is replied back by the firmware and the software publishes it as the PV we can see on the screen. IMAX can show "nan" in case an error flag is sent by the firmware. In the example above, the pyrodetector is disconnected and, so, Sum is calculated on noise, resulting in a negative number. IMAX was also negative and the firmware alerted us about this, what we can see as a "nan" inside a pink box.

The dashed blue lines indicate where the integration window is placed. The left side tells the system where to integrate the background noise while the right side configures where the real signal is. The chart below the raw waveform shows the result when multiplying the background by +1 and the signal by -1. The system will integrate this second waveform to get the non-calibrated length measurement. The calibration parameters and windows adjustments are described in the next topic. 

Adjust calibration parameters

TMIT and the integral of the raw waveform are used to calculate the bunch length. The parameters that need to be input in the system are the integration windows, plus a linear adjustment function [f(x)=a.x+b], plus the coefficients of this equation:

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Each group of elements will be broken into sections for better comprehension:

Adjustment of the integration windows

Coefficients of the equation

Linear adjustment function