Results of L3 BGO calorimeter calibration using an RFQ accelerator

A novel calibration system based on a radio-frequency-quadrupole (RFQ) accelerator has been installed in the L3 experiment. Radiative capture of 1.85 MeV protons from the RFQ accelerator in a lithium target produces a high-intensity flux of 17.6 MeV photons which are used to calibrate 11,000 crystals of the L3 BGO calorimeter. In this paper, we present results of the first fully successful RFQ run, taken in November 1997. We achieved a calibration precision of 0.6% in the barrel and 0.7% in the endcaps of the L3 BGO calorimeter. The RFQ-97 calibration proved to be the best one of all calibration techniques used in the L3 experiment.