What is the electron energy scale calibration? I am reading a paper from ATLAS collaboration in CERN and it is mentioned the "electron energy scale calibration" many times. It must be related to energy calibration in the experiment but I would like to know more what it means and which is the core procedure. 
Thank you to anyone who answers. 
 A: Essentially all particle detection instruments convert energy lost by the particle into an analog electrical signal which is then digitized and recorded somehow.
For many applications a simple binary result (there was a particle here at this time/there was not a particle here) is sufficient, but the job of calorimeters is to determine the (kinetic) energy of a particle by converting all of it to signals which are then measured. 
For that application you need a properly calibrated conversion factor between charge on the wires and energy of the particle. 
This is complicated because the actual conversion depends on the spieces of particle and on just how much energy the particle had at the time of the measurement (and changes very rapidly for particles that are almost stopped, which is the ideal case for particle in a calorimeter). Working out a algorithm to take the readings from the calorimeter and work up a total energy measurement is known as getting the energy scale.
So the paper is referring to the calculation by which collected charge (presumably in the ECAL) is used to assign an energy to a particle particle that has been IDed as an electron.
