Crabbed Waist Scheme at DA  NE M. Zobov for DA  NE Upgrade Team SuperB IV, November 2006 Monte Porzio Catone - Italy

Main Purposes 1.To increase the DA  NE luminosity by one order of magnitude 2.To test the “crabbed waist” idea – the basic idea of the SuperB project

Good occasion to perform the experiment at DA  NE 1.Fits DA  NE schedule (shut down for SIDDHARTA installation in mid 2007) 2.Satisfies new physics programs (SIDDHARTA, KLOE2,....) 3.Requires minor modifications 4.Relatively low cost (1 mln Euro) 5.No magnetic detectors, no splitter magnets, almost no parasitic crossings

32 nd LNF Scientific Committee 31 May-1June 2006 a) b) c)

Energy, GeV 0.51 Circumference, m97.69 RF Frequency, MHz Harmonic Number120 Damping Time, ms17.8/36.0 Bunch Length, cm1-3 Emittance, mm x mrad0.34 Coupling, % Beta Function at IP, m1.7/0.017 Max. Tune Shifts Number of Bunches111 Max.Beam Currents, A2.4/1.4 DA  NE Parameters (KLOE configuration)

Best Daily Integrated Luminosity 10 pb -1 /day L max = 1.53x10 32 cm -2 s -1

1.Large Piwinski’s angle  = tg(  z /  x 2.Vertical beta comparable with overlap area  y  x /  3.Crabbed waist transformation y = xy’/(2  ) Crabbed Waist in 3 Steps P. Raimondi, November 2005

Parameters used in simulations Horizontal IP0.2 m (1.7 m) Vertical IP0.65 cm (1.7 cm) Horizontal tune5.057 Vertical tune5.097 Horizontal emittance0.2 mm.mrad (0.3) Coupling0.5% Bunch length20 mm (32mm,24mm) Total beam current2 A (2.4A, 1.4A) Number of bunches110 (110) Total crossing angle50 mrad (25 mrad) Horizontal beam-beam tune shift0.011 Vertical beam-beam tune shift0.080 L => 2.2 x cm -2 s -1

With the present achieved beam parameters (currents, emittances, bunchlenghts etc) a luminosity in excess of is predicted. With 2Amps/2Amps more than 2*10 33 is possible Beam-Beam limit is way above the reachable currents M. Zobov (BBC Code by Hirata)

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

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

Crab On: Crab Off: Lmax = 2.97 x Lmin = 2.52 x Lmax = 1.74 x Lmin = 2.78 x 10 31

Siddharta IR Luminosity Scan above half-integers L max = 3.05 x cm -2 s -1 L min = 3.28 x cm -2 s -1

Optics, exists a good solution that meets all the requirements: IP-betas emittances phase advance wrt sextupoles dynamic aperture compatibility with old “Dear” parameters background lifetimes physical layout

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

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

Near IR Layout No splitters (on both sides) No dispersion in sextupoles due to splitters Needs new extremely simplified vacuum pipe (round everywhere, apart the y-one) Dipole fields need to be adjusted (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 Design almost completed

IR layout New beam line IP QD0sQF1s M.Biagini

IR: Defined the solution for the Interaction region Permanent Magnets Quads design almost completed by the vendor cost estimate by the vendor vacuum pipe design almost completed

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 Separated Siddharta

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$

MAFIA Time Domain Simulations B.Spataro and M.Zobov, 04/10/2006 σ z (cm) K l (V/Q) W max (V/Q) W min (V/Q) Z / n (mΩ) P (Watts) I = 20 mA N = 110 bunches f 0 = 3.06 MHz 3D model 2D cross-section

B.Spataro and M.Zobov, 13/10/2006

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

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

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

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)

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

Multipurpose remotized positioning system y x ICE removal

ICE removed

Bunch Length Reduction Before at 130 kV Now at 130 kV Now at 180 kV 30% 30% reduction in the e - bunch length as expected no quadrupole instability

e - vertical vize Blow up f(V RF, I b ) Data taken during the last KLOE run before ICE removal ! Presently no beam blow up observed with: RF voltage Beam current

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

Cost estimate Kilo-Euros PM quads 300 IR1 vacuum chambers 30 IR2 vacuum chambers20 Kickers pulsers 200 Kickers50 Matching chambers for kickers (and valves)50 Vacuum pumps10 New wigglers poles 200 External labor60 Contingency100 Total 1020

Conclusions 1.Numerical simulations give encouraging results 2.Engineering design (mechanical, vacuum, electromagnetic..) is well in progress. 3.We hope to start the crabbed waist collisions already in 2007.