Input Data

DRS4 corrections and pixel calibrations are based on:

Flat-field (FF) events :

Events produced by the Calibox [4], which uniformly illuminates the camera with the diffused light of a laser (𝜆 = 355 nm). Two filters in front of the laser permit to modulate the signal from 1 pe till the LG channel saturation. Standard FF events signal correspond to ~80 pe/pixel (filters 52). Cat-A calibration event statistical values (as median charge or charge standard deviation, see Pixel Calibration) are in general extracted from samples of 10,000 events.

Pedestal events :

Events triggered without signal. We distinguish two types of pedestal events:

• Dark pedestals: events from random triggers, taken with closed camera for DRS4 corrections

• NSB pedestals: events from fixted frequency triggers, taken with open camera for evaluating NSB pedestals and dc_to_pe calibration.