Energy scale calibration of KEDR detector tagging system

Abstract

The tagging system of the KEDR detector is a symmetrical focusing magnetic spectrometer for electrons and positrons scattered at small angles; it is embedded into the lattice of the VEPP-4M collider and intended for two-photon processes study. It measures scattered electron energy with resolution $\Delta E/E_0=0.03\%...0.6\%$ ($E_0$ is the beam energy). For precise energy scale calibration two methods are used: tagging of bremsstrahlung electron/positron by the photon energy measured by BGO calorimeter, and direct calibration using Compton backscattering spectrum edge. This report covers design and current status of the calibration system.

arXiv commentProceedings of Instrumentation for Colliding Beam Physics (27 February - 3 March, 2017; Budker Institute of Nuclear Physics, Novosibirsk, Russia) 6 pages, 4 figures