- Data set: FCS test run 23027048 (FcsGainCalibration)

  - Initial gain correction input: are based on the gain correction after calculating the 2nd iteration gain correction result from day 007 test runs.

  - Event selection: 1. each cluster energy > 1 GeV    2. energy asymmetry for cluster pair < 0.7    3. keep the only best cluster pair with highest energy

  - Fit function: Gaussian (signal) and power * exponential (background) function to fit for the plot (signal + background)