Compton Backscattering for the Calibration of KEDR Tagging System

摘要

KEDR detector has the tagging system (TS) to study the gamma-gamma processes.To determine the two-photon invariant mass, the energies of the scattered atsmall angles electrons and positrons are measured by the magnetic spectrometerembedded into the lattice of the VEPP--4M collider. The energy resolution(scattered electron/positron energy resolution divided by the beam energy) ofthis spectrometer varies from 0.6% to 0.03% depending on the electron/positronenergy. The Compton backscattering of laser radiation on the electron/positronbeam is used for the accurate energy scale and resolution calibration of thetagging system. The report covers the design, recent results and current statusof the KEDR TS calibration system.