1. 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

2. 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

3. 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

4. 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

5. 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

6. 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

7. Schematic view SuperB, Paris, May 9-11
A.Bogomyagkov, C-tau factory with crab waist in Novosibirsk

8. Source of polarized electrons
Polarized electron source for AmPS
Beam polarization – 80 %
Cathode voltage kV
Photocathode type Strained InGaAsP
Laser type Ti – Sapphire
Light wavelength – 850 nm
Laser power in a pulse W
Pulse duration s
Repetition rate Hz
Maximum current from a gun mA
Operational current – 20 mA
Photocathode lifetime – 560 hours
SuperB, Paris, May 9-11
A.Bogomyagkov, C-tau factory with crab waist in Novosibirsk

9. Injection facility SuperB, Paris, May 9-11
A.Bogomyagkov, C-tau factory with crab waist in Novosibirsk

10. Injection facility upgrade
Today:
21010 e-/pulse  (1.5% conversion)  3 108 e+/pulse
 50 Hz = 1.51010 e+/s
Upgrade:
e- current increase ( 3)
Better focusing in positron linac ( 1.5)
Debuncher using ( 2)
= 1.351011 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

11. 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

12. Main Ring (Parameters)
Energy
2000 MeV
Circumference
762.7 m
Max.current
2.2 A
Total number of particles
3.61013
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
71010
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
24109
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

13. 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

14. 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

15. 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
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

16. 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

17. FF Bandwidth Chromatic functions MR (Final Focus) -2
SuperB, Paris, May 9-11
A.Bogomyagkov, C-tau factory with crab waist in Novosibirsk

18. 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

19. 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

20. MR (Collective effects)
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A.Bogomyagkov, C-tau factory with crab waist in Novosibirsk

21. MR (longitudinal polarization) - 1
SuperB, Paris, May 9-11
A.Bogomyagkov, C-tau factory with crab waist in Novosibirsk

22. 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

23. MR (beam life time) Luminosity life time ~2000 s
SuperB, Paris, May 9-11
A.Bogomyagkov, C-tau factory with crab waist in Novosibirsk

24. 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

25. Luminosity 2 Crab sextupole detuning and beam-beam effects z=1210-3
SuperB, Paris, May 9-11
A.Bogomyagkov, C-tau factory with crab waist in Novosibirsk

26. 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

27. 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

28. 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 DANE 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