The document describes the calibration of the calorimeter for the DVCS experiment in Hall A using π0 events. It discusses two methods for calibration: 1) elastic calibration using ep→e'p' events and 2) π0 calibration using ep→e'p'π0→e'p'γγ events. The π0 calibration involves minimizing the difference between theoretical and measured photon energies using calibration coefficients. Iterating the process allows the coefficients to converge. Applying the calibrated coefficients to data groups improves the agreement of the invariant mass and missing mass distributions with expected values. The calibration is effective and will be continued with more data.