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Poster session: Modern trends of accelerator development, large ac- celerator design, colliding beams


S.A.Nikitin (Budker Institute of Nuclear Physics, Novosibirsk, Russia)

Influence of Errors in KEDR Detector Field Compensation on the Spin Tune Shift and the Beam Polarization Lifetime in VEPP-4M Collider at Energy of Tau Lepton Production Threshold

At present the experiment on precision measurement of tau lepton mass at VEPP-4M stor- age ring-collider with KEDR detector using the resonant depolarization technique is in process. Polarized beams needed in this technique are injected from VEPP-3 booster stor- age ring. The beam energy in experiment is near tau production threshold (1777 MeV) where a vicinity of the spin integer resonance (1763 MeV) strongly amplifies an influence of various field imperfections on spin motion. In particular, a spin tune shift, related to the energy quantity not through a simple proportional law, appears. Beside, a depolarization processes become significant. A few percent difference from zero of the longitudinal magnetic field integral in KEDR is worth to be considered in this viewpoint. We have studied the effects of KEDR field compensation errors on an accuracy of beam energy calibration by spin precession frequency as well as on a "lifetime" of beam polarization in VEPP-4M. Results of special experiments are presented and discussed in comparison with the calculation.

Dr. Sergei Alexeevich Nikitin: nikitins@inp.nsk.su


A.V.Bogomyagkov, S.A.Nikitin, A.G.Shamov (Budker Institute of Nuclear Physics, Novosibirsk, Russia)

Influence of the vertical closed orbit distortions on accuracy of the en- ergy calibration done by resonant depolarization technique


The series of the experiments on precise mass measurement of J/


mesons have been

performed in 2002-2004. Energy calibration has been done with the help of the resonant depolarization technique. The present report discusses the influence of the vertical orbit distortions on the accuracy of the energy calibration. The sources of the orbit distortions are misalignment of the quadrupoles and sextupoles in vertical plane and kicks of the ver-

tical correctors.

Anton Bogomyagkov: A.V.Bogomyagkov@inp.nsk.su


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