Status of electron-positron collider VEPP-2000
摘要
The main goal of VEPP-2000 construction is to measure the cross sections of hadron production in e + e annihilations and to collect an integral luminosity about few inverse femtobarns in the energy range 0.4 – 2 GeV. To reach these goals, the Round Beam Concept (RBC) was realized at VEPP-2000 collider. RBC requires equal emittances, equal small fractional tunes, equal beta functions at the IP, no betatron coupling in the arcs [1]. Such an approach results in conservation of the longitudinal component of particle’s angular momentum. As a consequence, it yields an enhancement of dynamical stability, even with nonlinear effects from the beam-beam force taken into account. The first beam was injected in VEPP-2000 machine 5 years ago and RBC was successfully tested at VEPP-2000 in 2008 [2]. Two experimental seasons in 2010-2012 were performed with two detectors SND and CMD3 in the energy range between 500 and 1000 MeV. Now, the total luminosity accumulated at VEPP-2000 is near to the final result of the VEPP-2M collider. The single bunch luminosity of 3×10 31 cm -2 s -1 was achieved together with a maximum beam-beam tuneshift as high as 0.15. At present, the work is in progress to increase the rate of positron delivery and upgrade the booster ring BEP for the beam transfer up to the top collider energy of 1 GeV.