A system of beam energy measurement based on the Compton backscattered laser photons for the VEPP-2000 electron–positron collider

Abstract

The beam energy measurement system for the VEPP-2000 electron-positron collider is described. The method of Compton backscattering of CO laser photons on the electron beam is used. The relative systematic uncertainty of the beam energy determination is estimated as 6 · 10 −5 . It was obtained through comparison of the results of the beam energy measurements using the Compton backscattering and resonance depolarization methods.

Measurement of hadronic cross-sections at VEPP-2000

“…During the 2012 season the beam energy monitoring system [8,9] has been installed and commissioned. The system allows to continuously monitor beam energy concurrently with data taking with relative precision < 10 −4 using Compton backscattering of laser photons at the electron beam.…”

Beam energy determination in experiments at electron-positron colliders

“…This approach was developed and experimentally proved in ref. [4][5][6][7][8][9][10][11][12]. First measurement of the beam energy E ≈ 1.3 GeV at storage ring of Taiwan Light Source with accuracy δ E/E ∼ 10 −3 was reported in ref.…”

“…The accuracies was proved by comparison with results of RD method. In collider experiments, the CBS method was applied at VEPP-4M [10] and the τ − charm factory BEPC-II [11] for measurement of beam energy 1 -2 GeV, and at VEPP-2000 below 1 GeV [12].…”

The system for delivery of IR laser radiaton into high vacuum

“…In collider experiments, the CBS method was applied at VEPP-4M [2], the τ − charm factory BEPC-II [3] and at VEPP-2000 [4]. For insertion of the laser beam into the vacuum chambers of these colliders the laser-to-vacuum insertion system was developed.…”