The project of t-charm factory with crab waist in Novosibirsk A.Bogomyagkov for the C-tau team Budker INP, Novosibirsk SuperB, Paris, May 9-11 A.Bogomyagkov, C-tau factory with crab waist in Novosibirsk
Contributors A.Blinov E.Levichev A.Bogomyagkov P.Logachiov A.Bondar’ S.Nikitin V.Kiselev P.Piminov I.Koop D.Shatilov G.Kurkin S.Sinyatkin A.Skrinsky SuperB, Paris, May 9-11 A.Bogomyagkov, C-tau factory with crab waist in Novosibirsk
C-tau Conceptual Design Report in Novosibirsk History remarks C-tau Conceptual Design Report in Novosibirsk ► E = 700 – 2500 MeV ► Round beams L = 1034 cm-2s-1 ► Monochromatization L ~ 1032 cm-2s-1 ► Long. Polarization L ~ 1034 cm-2s-1 ► Transverse polarization for precise energy calibration 1995 SuperB, Paris, May 9-11 A.Bogomyagkov, C-tau factory with crab waist in Novosibirsk
Reasons for rebirth ► Improvement of the economic situation in Russia ► Exciting results of B-factories ► Invention of the crab waist collision scheme (P.Raimondi, March 2006) SuperB, Paris, May 9-11 A.Bogomyagkov, C-tau factory with crab waist in Novosibirsk
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-2s-1, longitudinal polarization SuperB, Paris, May 9-11 A.Bogomyagkov, C-tau factory with crab waist in Novosibirsk
Summary ► Variable energy Ecm= 3 – 4.5 GeV (from J/psi to charm barions) ► L = 1035 cm-2s-1 ► At least one beam (e-) should be polarized longitudinally ► No energy asymmetry is needed ► No beam monochromatization is needed ► Energy calibration with medium accuracy (Compton backscattering) SuperB, Paris, May 9-11 A.Bogomyagkov, C-tau factory with crab waist in Novosibirsk
Schematic view SuperB, Paris, May 9-11 A.Bogomyagkov, C-tau factory with crab waist in Novosibirsk
Source of polarized electrons Polarized electron source for AmPS Beam polarization 60 – 80 % Cathode voltage 100 kV Photocathode type Strained InGaAsP Laser type Ti – Sapphire Light wavelength 700 – 850 nm Laser power in a pulse 200 W Pulse duration 2.1 s Repetition rate 1 Hz Maximum current from a gun 150 mA Operational current 15 – 20 mA Photocathode lifetime 190 – 560 hours SuperB, Paris, May 9-11 A.Bogomyagkov, C-tau factory with crab waist in Novosibirsk
Injection facility SuperB, Paris, May 9-11 A.Bogomyagkov, C-tau factory with crab waist in Novosibirsk
Injection facility upgrade Today: 21010 e-/pulse (1.5% conversion) 3 108 e+/pulse 50 Hz = 1.51010 e+/s Upgrade: e- current increase ( 3) Better focusing in positron linac ( 1.5) Debuncher using ( 2) = 1.351011 e+/s Reserve: electron energy can be increased by 100 MeV ( 1.3) SuperB, Paris, May 9-11 A.Bogomyagkov, C-tau factory with crab waist in Novosibirsk
2.5 GeV linac ► Using the same accelerating structure as for the existing injection facility ► 13 accelerator modules (200 MeV, 16 m) each of 4 accelerator structures. Totally 208 m ► In a 1-m straight section between the accelerator structures there are two quadrupoles, BPM and vacuum valve ► Four accelerator structures (one module) are fed by one 5045 klystron (SLAC) ► Repetition frequency is 50 Hz SuperB, Paris, May 9-11 A.Bogomyagkov, C-tau factory with crab waist in Novosibirsk
Main Ring (Parameters) Energy 2000 MeV Circumference 762.7 m Max.current 2.2 A Total number of particles 3.61013 RF frequency 500 MHz Harmonic number 1289 Compaction factor ~0.001 Damping times ~20-40 ms Energy spread ~0.08% Natural emittances (hor/ver) 10/0.2 nm No. of bunches 514 Particles per bunch 71010 Bunch length 1 cm Betas star (ver/hor) 0.075/2 cm Space charge parameters 0.1, 0.005 Injection frequency 50 Hz Particles/injection 24109 Half crossing angle – 20 mrad Luminosity – 1035 cm-2s-1 SuperB, Paris, May 9-11 A.Bogomyagkov, C-tau factory with crab waist in Novosibirsk
MR (Layout) 1. Gradient wigglers (emittance control) 2. Matching cell 3. Damping wigglers, RF and injection 4. Matching cell 5. Final focus Arcs - FODO SuperB, Paris, May 9-11 A.Bogomyagkov, C-tau factory with crab waist in Novosibirsk
MR (damping and exciting wigglers) Main idea to keep (almost) constant emittance, bunch length and horizontal damping time. Field amplitude for damping and exciting wigglers SuperB, Paris, May 9-11 A.Bogomyagkov, C-tau factory with crab waist in Novosibirsk
MR (parameters vs. energy) 1.5 GeV 1.85 GeV 2 GeV 2.5 GeV L, m 762.71 Qx 24.53 Qy 24.57 Cx -117 Cz -229 -231 -232 Coupling 0.02 Em, nm*rad 10 SigL, mm dE/E*10^3 0.63 0.668 0.706 0.869 taux, msec 30 17 Alfa*10^3 1.02 1.11 1.13 1.21 Uo, MeV 0.252 0.31 0.34 0.788 Urf, MV 0.5100 0.7353 0.8845 1.833 Qs 0.0079 0.0091 0.0097 0.01281 dE_acc_RF[%] 0.76 0.868 0.9537 1.1204 SuperB, Paris, May 9-11 A.Bogomyagkov, C-tau factory with crab waist in Novosibirsk
MR (Final Focus) -1 Pair Y sexts, -I Pair X sexts, -I Crab sexts SuperB, Paris, May 9-11 A.Bogomyagkov, C-tau factory with crab waist in Novosibirsk
FF Bandwidth Chromatic functions MR (Final Focus) -2 SuperB, Paris, May 9-11 A.Bogomyagkov, C-tau factory with crab waist in Novosibirsk
MR (lattice) Wiggler FODO Arcs FODO Dipole 140 Quadrupole 180 Sextupole 188 E.Wiggler 16 D.Wiggler 24 SuperB, Paris, May 9-11 A.Bogomyagkov, C-tau factory with crab waist in Novosibirsk
MR (dynamic aperture) SuperB, Paris, May 9-11 z/z x/x SuperB, Paris, May 9-11 A.Bogomyagkov, C-tau factory with crab waist in Novosibirsk
MR (Collective effects) SuperB, Paris, May 9-11 A.Bogomyagkov, C-tau factory with crab waist in Novosibirsk
MR (longitudinal polarization) - 1 SuperB, Paris, May 9-11 A.Bogomyagkov, C-tau factory with crab waist in Novosibirsk
MR (longitudinal polarization) - 2 - SC solenoid in the injection section turns the spin around the velocity by π. Required field integral is 10.5∙E [T-m] (E in GeV). - In IP Siberian Snake keeps the polarization vector orientation along the beam velocity. Spin precession tune =½ for any energy. - Betatron coupling is compensated locally in the π-solenoid section by skew quadrupoles. - Radiation polarization is suppressed compared to the vertically polarized machines. Special radiation wigglers are needed to provide a beam self-polarization based on the so-called “kinetic” mechanism depending on the spin-orbital coupling. SuperB, Paris, May 9-11 A.Bogomyagkov, C-tau factory with crab waist in Novosibirsk
MR (beam life time) Luminosity life time ~2000 s SuperB, Paris, May 9-11 A.Bogomyagkov, C-tau factory with crab waist in Novosibirsk
Luminosity 1 Crab off Crab on Lm=1.8x1035 Lm=1.2x1035 SuperB, Paris, May 9-11 A.Bogomyagkov, C-tau factory with crab waist in Novosibirsk
Luminosity 2 Crab sextupole detuning and beam-beam effects z=1210-3 SuperB, Paris, May 9-11 A.Bogomyagkov, C-tau factory with crab waist in Novosibirsk
Present situation - 1 Damping ring 500 MeV e+ linac Conversion system Klystron gallery SuperB, Paris, May 9-11 A.Bogomyagkov, C-tau factory with crab waist in Novosibirsk
Present situation - 2 2.5 GeV linac tunnel Injection tunnel Vertical magnet support D.Shatilov goes to the IP SuperB, Paris, May 9-11 A.Bogomyagkov, C-tau factory with crab waist in Novosibirsk
Conclusion C-tau factory with L = 1035 cm-2s-1 seems to be an extremely attractive facility for HEP experiments. - Crab-waist crossing approach allows us to obtain such luminosity with achievable machine parameters: required beam intensity, low emittance, injection efficiency, polarization features have been already obtained in B-factories, light sources, etc. Crab crossing is the only concept that should be checked. That’s why the crab crossing experiment in DANE is of a great importance. - At BINP we have an advantage-ground to start the C-Tau project: injection facility is under commissioning, tunnels for linac and injection lines are ready, a lot of the facility solutions are based on existing wares and technologies. - Future plans for the project design: FF improvement, dynamic aperture optimization, BB study, Touschek lifetime increase, etc. SuperB, Paris, May 9-11 A.Bogomyagkov, C-tau factory with crab waist in Novosibirsk