A bootstrap method for gain calibration and resolution determination of a lead-glass calorimeter

We describe a method for calibration of a lead-glass calorimeter that does not require a beam of known energy. The technique was used to calibrate the radphi lead-glass calorimeter at Jefferson Lab. The technique described can be applied to any segmented electromagnetic calorimeter capable of detecting all-photon decays of mesons, for example, π0→2γπ0→2γ, η→2γη→2γ or ω→π0γω→π0γ. We also demonstrate how the measured 2γ2γ mass width of the π0π0 and ηη mesons can be unfolded to extract the single-shower energy and position resolution functions of the calorimeter.