1. Dafne Upgrade with large Piwinsky angle and crab waist P. Raimondi Gruppo1 Nov.2006

2. Outline Dafne luminosity History Goals for the Finuda run Goals for the Siddarta run Mid-Long term plans

3. Luminosity history

4. DA  NE DELIVERED L IN YEAR 2004-5 for KLOE 109-111 bunches I - peak =2.05 A I + peak = 1.39 A L peak = 1.53e32 cm -2 s - 1 L day peak = 9.9 pb -1 L month > 215 pb -1 L 2004-5 > 2200 pb -1

5. 2006-7 goals LNF September 2006 Finuda Run: Goal 1ft -1 by April 30, 2007 - Start Oct-02 with cold check-outs - 1 month commissioning - 6 months data taking Siddartha Run: Goal 1ft -1 by Dec 31, 2007 - Install the new IR with cross-angle/crab-waist and Siddartha detector (2-3 months) - start July-1 st or Sept 1 st - 1 month commissioning - 3 months data taking Dafne Goal: 10 33 By Dec 31, 2007

6. Finuda Run Started on Oct-02 Reestablished collisions, stored >700mAmps e+/e- Vacuum conditioning ‘til Oct-31 Better coupling correction wrt Kloe (just 2 rotating quads instead of 4): 10% Better feedbacks >10% (more current and more stable beams) Reduced wiggler field (-5%) Reduced run duration 0.6*10^32 0.1ft-1/month NOW 1.5*10^32 by the end of the run, 0.2ft-1/month duable

7. Siddarta Luminosity New IR needed for Siddarta around mid-2007 Very straightforward its design to overcome some of the present limitations and test the large crossing angle scheme No more parasitic crossing Very small vertical beta function Large Piwinsky angle Crab waist Fast kickers installed Better injection efficiency: 50%=>100% No background=> topping up Higher currents => more luminosity (10%) Wigglers pole modified to improve acceptance Longer lifetimes Less backgroung Higher integrated luminosity (10%) Ti Coating in the e+ wigglers chambers Decreased e-cloud => Higher e+ current, more luminosity (20%)

8. High luminosity requires: - short bunches - small vertical emittance - large horizontal size and emittance to mimimize beam-beam For a ring: -easy to achieve small horizontal emittance and horizontal size -Hard to make short bunches Crossing angle swaps X with Z, so the high luminosity requirements are naturally met Luminosity goes with 1/  x and is weakly dependent by  z

9. Vertical waist has to be a function of x: Z=0 for particles at –  x (-  x /2  at low current) Z=  x /  for particles at +  x (  x /2  at low current) Crabbed waist realized with a sextupole in phase with the IP in X and at  /2 in Y 2Sz 2Sx  z x 2Sx/  2Sz*  e- e+ YY Crabbed waist removes bb betratron coupling Introduced by the crossing angle

10. SuperB parameters Collisions with uncompressed beams Crossing angle = 2*25mrad Negligible Emittance growth Horizontal PlaneVertical Plane

11. Luminosity considerations Ineffectiveness of collisions with large crossing angle is illusive!!! Loss due to short collision zone (say l=σ z /40) is fully compensated by denser target beam (due to much smaller vertical beam size!). Number of particles in collision zone: No dependence on crossing angle! Universal expression: valid for both - head-on and crossing angle collisions! I. Koop, Novosibirsk

12. Tune shifts Raimondi-Shatilov-Zobov formulae: (Beam Dynamics Newsletter, 37, August 2005) Super-B: One dimensional case for β y >>σ x /θ. For β y <σ x /θ also, but with crabbed waist! I. Koop, Novosibirsk

13. Beam-Beam Tails at (0.057;0.097) A x = ( 0.0, 12  x ); A y = (0.0, 160  y )

14. Siddharta IR Luminosity Scan Crab On --> 0.6/  Crab Off L max = 2.97x10 33 cm -2 s -1 L min = 2.52x10 32 cm -2 s -1 L max = 1.74x10 33 cm -2 s -1 L min = 2.78x10 31 cm -2 s -1

15. K.Ohmi

17. “Crabbed” waist optics IP Δμ x =π Δμ y =π/2 Δμ x =π Δμ y =π/2 +g -g Appropriate transformations from first sextupole to IP and from IP to anti-sextupole: Sextupole lensAnti-sextupole lens I. Koop, Novosibirsk

18. Synchrotron modulation of ξy (Qualitative picture) ξ y (z-z 0 ) Relative displacement from a bunch center z-z 0 Head-on collision. Flat beams. Tune shift increases for halo particles. Head-on collision. Round beams. ξ y =const. Crossing angle collision.Tune shift decreases for halo particles. Conclusion: one can expect improvement for lifetime of halo-particles! I. Koop, Novosibirsk

19. With the present achieved beam parameters (currents, emittances, bunchlenghts etc) a luminosity in excess of 10 33 is predicted. With 2Amps/2Amps more than 2*10 33 is possible Beam-Beam limit is way above the reachable currents M. Zobov Present achieved currents L=1.5e32

20. Very weak luminosity dependence from damping time given the very small bb-blowup Wigglers off Dafne Wigglers SC Wigglers Wigglers off SC Wigglers Dafne Wigglers M. Zobov

21. IR layout New beam line IP QD0sQF1s M.Biagini

22. IR Layout No splitters (on both sides) Common beam pipe in QD0 Separated beam pipes since QF1 No dispersion in sextupoles due to splitters Needs new extremely simplified vacuum pipe (round everywhere, apart the y-one) Dipole fields need to be ajusted (B long lower, B short higher)  use splitters power supplies Doublets will be PM All the other elements (quads, sexts etc) are in place, need just to be moved nearby

23. View of the modified IR1 region Similar modifications will be made in the IR2, without the low-beta insertion In addition in IR2 the two lines will be Vertically Separate Siddarta

25. QD0 Qf1s Permanent SmCo quads already ordered (about 380K$ for 6 quads) All other IR magnets and power supplies reused Most of the Vacuum Pipes and pumps reused New Vacuum pipes and pumps around 50K$

27. Parameters for the Siddarta run Np=2.65*10^10 I=13mAmp*110bunches Emix=200nm Emiy=1nm Coupling= 0.5% sigx=200um betx=0.2m sigy=2.4um bety=6.0mm sigz=20mm X_angle=2*25mrad L(110bunches,1.43A)=10 33 y=y+0.8/  *x*y’ crabbed waist shift Np=2.65*10^10 I=13mAmp*110bunches Emix=300nm Emiy=1.5nm Coupling= 0.5% (with no BB) sigx=700um betx=1.6m sigy=15um (5um with no BB) bety=19.0mm sigz=25mm X_angle=2*16mrad L(110bunches,1.43A)=1.5*10 32 Parameters during the Kloe run

28. Optical functions and dynamic apertures > 20 sigma_x > 12 sigma_y full coupled

29. IR optics  x =0.2m  y =6.0mm New betas  x =1.4m  y =19.0mm Old betas M.Biagini

30. mode1mode2mode3mode4 Driven mode solution Short circuit at ports F.Marcellini and D. Alesini 150 W

32. Measures to Increase Positron Current 1.New Injection Kickers 2.New Feedback Systems 3.Ti-Coating

33. New Injection Kickers Expected benefits: higher maximum stored currents Improved stability of colliding beams during injection less background allowing acquisition on during injection ? (D. Alesini and F. Marcellini) New injection kickers with 5.4 ns pulse length have been designed to reduce the perturbation on the stored beam during injection present pulse length ~150ns (old kickers) t t VTVT VTVT FWHM pulse length ~5.4 ns 50 bunches 3 bunches

34. Kickers: design completed, asked vendors for offers test of the pulsers in progress - one borrowed for preliminary tests (30KV max) - one tested up to 50 KV, but out of specks for time- duration - one more shipped (in specks) still problems on the high-voltage feed through (found a working solution already, but working on improvements)

35. Third generation digital bunch-by-bunch feedback system designed for SuperB factory (collaboration SLAC-KEK-LNF) - Features: - extremely compact - gain & phase digital and remote control - possibility to manage any betatron or synchrotron tunes - robust response to big oscillations due to injection (using FIR filter at 8/16 taps) - real time parameter monitoring - powerful beam diagnostics - main DSP loop based on FPGA (Field Programmable Gate Array) iGp the new feedback system under test at SLAC, KEK and LNF A.Drago

36. Wiggling wiggler Motivation: Build wiggler poles symmetric with respect to the beam orbit Wigglers pole modifications: design completed poles should be replaced during the shutdown

37. Cost estimate Kilo-Euros PM quads 350 IR1 vacuum chambers 75 IR2 vacuum chambers 75 Kickers pulsers 250 Kickers70 Matching chambers for kickers (and valves)60 Vacuum pumps30 New wigglers poles 230 Plants Mods60 External labor80 Contingency100 Total 1380+VAT

38. Dafne 2008 and beyond If 10 33 is achieved (or some above 5*10 32 ) KLOE will start a new run with an upgraded detector. the only significant (in money) modifications on Dafne could be: - Transfer lines mods to allow trickle injection - High Energy mods for NNbar experiment: New Dipoles Possibly X-Band Linac in the transfer lines to allow on energy injection If the luminosity does not seems satisfactory, the only other possibility left (at the present) is the new machine DANAE, already at an advanced project state.

39. Dafne Goals Conclusions A new IR for Siddarta compatible with large-crossing angle option seems feasible Same IR can fit in KLOE(1 or 2) Predicted large luminosity boost based exclusively on pure “back of the envelope” geometric considerations, fully supported by extensive simulations 10 times more luminosity for a given current leads to a 10 times better luminosity/background ratio. Additional gain comes from the increased (about a factor 1.2) beam stay clear in the IR Possible to do top-of-the-line Accelerator Physics and R&D for future factories (e.g: SuperB) Simply rematching the IP betas, it will be possible to run like with KLOE 2004-5, with even larger beam stay clear across the doublet:  x : 0.2m => 1.4m  y : 6.0mm => 18mm