Upgrade of Beam Energy Measurement System at BEPC-II

TL;DR

This paper describes the upgrade of the beam energy measurement system at BEPC-II, enhancing accuracy and reliability through hardware improvements to support precise physics experiments at BES-III.

Contribution

The paper details specific hardware and subsystem upgrades that improve the measurement system's accuracy and operational stability at BEPC-II.

Findings

Enhanced measurement accuracy and stability.

Successful integration of upgraded components.

Reliable offline energy data for physics analysis.

Abstract

The beam energy measurement system is of great importance and profit for both BEPC-II accelerator and BES-III detector. The system is based on measuring the energies of Compton back-scattered photons. Many advanced techniques and precise instruments are employed to realize the highly accurate measurement of positron/electron beam energy. During five year's running period, in order to meet the requirement of data taking and improve the capacity of measurement itself, the upgradation of system is continued, which involve the component reformation of laser and optics subsystem, replacement of view-port of the laser to vacuum insertion subsystem, the purchase of electric cooling system for high purity germanium detector, and the improvement of data acquisition and processing subsystem. The upgrading of system guarantees the smooth and efficient measuring of beam energy at BEPC-II and accommodates the accurate offline energy values for further physics analysis at BES-III.