BINP Tau-Charm Project Update E. Levichev, BINP, Novosibirsk Super. B Workshop LAL, Orsay, February 15 -18, 2009
Topics: 1. Novosibirsk CT Project briefly 2. IR design 3. FF and QD 0 4. Polarization insertions
Layout Injection facility exists Tunnel for the linac and the technical straight section of the factory is ready
Scientific case ► D-Dbar mixing ► CP violation searches in charm decays ► Rare and forbidden charm decays ► Standard Model tests in leptons decays ► Searches for lepton flavor violation ► CP/T violation searches in t leptons decays Requirements: L > 1034 cm-2 s-1, longitudinal polarization ► Production of the polarized anti-nucleons Energy = 1 Ge. V with reduced luminosity
Specifications ► Variable energy Ecm= 3 – 4. 5 Ge. V (from J/psi to charm baryons) (2 – 4. 5 Ge. V? ) ► L = 1÷ 2× 1035 cm-2 s-1 (crab-waist approach) ► e-s are polarized longitudinally at IP ► No energy asymmetry ► No beam monochromatization ► Energy calibration with medium accuracy is enough (Compton backscattering)
Main accelerator parameters 8 m of the SC wigglers with 20 -cm-period are used to control the beam parameters at different energies
Luminosity D. Shatilov
IR Old A. Bogomyagkov P. Piminov New
Last modifications • Beta*x = 2 cm 3 cm (in QF 1 Beta x = 800 m 350 m) • Separation of the betas in SY & SX is better • –I between SY 1 –SY 2 & SX 1 -SX 2 is designed with very high accuracy • Sextupole length L = 30 20 cm • Special weak sextupoles (~3% of the main ones) correct 4 D DA very effectively • Special sextupoles open the energy bandwidth to ± 2% • Chromaticity of Betas is intrinsically small for the telescope scheme and sextupoles are used to zero the chromaticity of Alphas (Betas’)
Parameters old/new x 300 bunches = 1 x 1035
IR optics L 1/2 = 85 m
IR sextupole correction scheme
Telescope transformation A. Bogomyagkov Map: Twiss transformation: Transport notation: Chromaticity: Telescopic symmetry: Sextupoles to cancel
Bandwidth BW = ± 2%
DA correction P. Piminov
FF quadrupoles
QD 0 Cosine SC quadrupole with short end coil region with optimized 6 th and 10 th integrated harmonics (<10 -3) Active quench protection system with heater P. Vobly
QD 0 main coils connection Two additional current sources allows to compensate influence of the coils misalignment and manufacturing errors on the field with high accuracy. The tuning is done during the magnetic measurements.
QD 0 assembling
Polarization insertion I S. Nikitin Central arc Disadvantage: the scheme operates well only for the nominal energy. At the nominal energy the magnets rotate the spin around the field direction by (2 k+1) , k is integer. Solenoids rotate the spin by /2 around the velocity vector: a polarization vector is longitudinal at IP and transverse outside the polarization insertion.
Polarization insertion II Achromatic central arc Advantage: the scheme is optimally tuned by the solenoids in the whole energy range!
Polarization insertion III Arc Achromatic arc Longitudinal polarization degree, averaged on time and particle ensemble
Summary ► CT project interaction region is designed with parameters (bandwidth, dynamic aperture, crab sextupoles location, etc. ) satisfied the project requirements ► Design of the final focus superconducting quadrupoles is started and preliminary configuration of the large aperture QD 0, shared by both beams, with the required parameters is found ► New polarization insertion based on the achromatic arc is proposed. Solenoids allow to tune the polarization at IP in the wide energy range
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