Main Technical Issues of theSuper B Injector Main Technical Issues of the Super B Injector SuperB Meeting, Isola d’Elba, May 31st – June 3rd, 2008 D. Alesini, R. Boni, F. Marcellini, M. Preger, P. Raimondi, C. Vaccarezza, INFN-LNF J. Seeman, SLAC

OUTLINE SuperB Meeting, Isola d’Elba, May 31st – June 3rd, INJECTOR LAYOUT 2. POSITRON GENERATION & TIMING 3. RF LINAC STRUCTURE 4. ELECTRON GUN 5. PARAMETER LIST 6. COST ESTIMATE 7. SOME CONCLUSIONS

INJECTOR SCHEMATIC LAYOUT e- 7 Gev e+ 4 Gev Linac s-band (2856 MHz) - room-temperature e+ damping ring 1.2 GeV – 35 mt circumference ( could be the SLC e+ DR ) SuperB Meeting, Isola d’Elba, May 31st – June 3rd, 2008

INJECTOR Complex MAIN PARAMETERS SuperB Meeting, Isola d’Elba, May 31st – June 3rd, 2008 Parameters electrons positrons Energy (GeV) 7 4 Repetition rate (Hz) 100 Positron conversion energy (GeV) Conversion 3 GeV % N. of particles/bunch available for topping-up 5.5 x 10 9 N. of main-rings bunches1251 Re-filling time per ring (sec)12 ÷ 13 Time between re-fillings (sec)45 ÷ 50

POSITRON SOURCE for the SuperB SuperB Meeting, Isola d’Elba, May 31st – June 3rd, 2008 NLC P.S. ParameterSLC-94NLC-II Super  E (GeV) N of particles3.5 x x x Rep.rate (Hz) Beam power (kW) Int.l Conf. on High Energy Particle Accelerators, 1995 Beam power = E. N. e-. F

….. POSITRON GENERATION …. Positron converter 1251 e+ bunches 1251 e- bunches chicane 50 Hz kickers

Positron injection-extraction process The injection-extraction process must happen every ≈ 3 x damping time ….. i.e. 10 msec max rep. rate of RF power sources = 100 Hz. SuperB Meeting, Isola d’Elba, May 31st – June 3rd, 2008

… positron injection-extraction process 20 ÷ 30 nsec t SuperB Meeting, Isola d’Elba, May 31st – June 3rd, 2008 alternative inj-extr. layout t < ΔT

Kickers parameters, scaling from DAFNE DAFNE 510 MeV Deflection 5 mrad ( 1 m.) HV 45 kV Kicker length 1mt. Plates distance 5 cm Pulse width 5 nsec (virtual length ≈ 1.5 m ) SuperB 1 GeV Deflection 5 mrad HV 45 kV Kicker length 2.5 mt Plates distance 5 cm plate Pulse witdh 25 ÷ 30 nsec (virtual length ≈ 9 m ) SuperB Meeting, Isola d’Elba, May 31st – June 3rd, 2008

Input ports Output ports (LOAD) Strip ceramic supports BEAM Tapered stripline Elliptical cross section HV feedthrough DAFNE KICKERS SuperB Meeting, Isola d’Elba, May 31st – June 3rd, 2008

SLC damping ring A 1.2 CeV DAMPING RING COMPLEX FOR THE STANFORD LINEAR COLLIDER, G. E. FISCHER, W. DAVIES-WHITE, T. FIEGUTH, H. WIEDEMANN Stanford Linear Accelerator Center SLAC-PUB 3170, July 1983

e- 7 Gev e+ 4 Gev LINAC LAYOUT Room-temperature Linac less expensive, based on the LNF/SLAC know-how S-band … MHz same frequency of DAFNE-Linac, SPARC, SPARX project. Average accelerating gradient 23 MV/m medium-level E-field e+ DR 4 GeV linac1 GeV e+ target e- gun polarized e- DR e+ DR 7 GeV e- or e+ 4 GeV e+ or e- Spin rotator previous injector layout SuperB Meeting, Isola d’Elba, May 31st – June 3rd, 2008

RF POWER SOURCES S-band 2856 MHz Klystrons Output peak power 60 MW RF Pulse width 4 μsec Max rep. rate 100 Hz 60 MW klystrons are available by the RF Industry: CPI & SLAC mod TOSHIBA mod. E mt 60 MW SuperB Meeting, Isola d’Elba, May 31st – June 3rd, 2008

S-band ACCELERATING STRUCTURES Frequency 2856 MHz Type Const. gradient - TW Operating mode 2π/3 N° of RF cells 86 Length 3 mt Energy (50 MW input) 70 MeV – unloaded ≈ 60 MeV - loaded Main specifications SuperB Meeting, Isola d’Elba, May 31st – June 3rd, 2008

RF Power Station Layout Energy gain per Power Station 212 MeV Average accel. gradient (unloaded) 23.5 MV/m “ “ (with beam loading) ≈ 21 MV/m (10% less) SuperB Meeting, Isola d’Elba, May 31st – June 3rd, 2008

36 power stations 108 acc. structures active length 324 m. gradient 23.5 MV/m 49 power stations 98 acc. structures active length 294 m. gradient 25 MV/m 31 power stations 124 acc. structures active length 372 m. gradient 20 MV/m …. RF Power Station layout comparison

16 RF Stations 5 RF Stations 15 RF Stations RF Linacs Layout SuperB Meeting, Isola d’Elba, May 31st – June 3rd, 2008

N° of RF power stations36 N° of accelerating sections108 Klystron output peak power60 MW (4 μ sec ) Input RF power per section50 MW (1 μ sec ) Average accelerating gradient [unloaded] 23.5 MV/m Total average kly RF power800 kW Total wall-plug modulator power 3 MW Total wall-plug Injector power (incl. DR)≈ 4.5 MW Total injector length≈ 400 m. Total active RF length 324 m. SuperB Linac Main Specs. SuperB Meeting, Isola d’Elba, May 31st – June 3rd, 2008

electron gun SLC polarized electron gun DC gun activated GaAs photocathode 800 nm laser, laser light input GaAs photocathode SLC polarized Gun kV 7 x electrons in 1 nsec q ≈ 11 nC I ≈ 11 A SuperB Meeting, Isola d’Elba, May 31st – June 3rd, 2008 The Polarized Electron Gun for the SLC D. C Schultz, J. Clendenin, J. Frisch, E. Hoyt, L. Klaisner, M. Woods, D. Wright, M. Zolotorev Stanford Linear Accelerator Center, SLAC-PUB-5768, March 1992

Main rings particles/bunchn b = Particles injected for topping-upn i = Efficiency of e+ transport from PCη + ≈ 0.9 N. of positrons after PCN+ = N. of electrons at the PC (e-/e+ conversion 3 GeV = 10%) N - PC = q - PC = 10 nC Electron transport efficiencyη - ≈ 0.9 N. of e- from the Gun for e+ production (SLC polarized gun) N - G = q - G = 11 nC Electron Gun current11 A (1 nsec) Main rings re-filling time2 x 12.5 sec Time between injections45 ÷ 50 sec SuperB Meeting, Isola d’Elba, May 31st – June 3rd, 2008 e-/e+ Production Capability

Schematic view of the injector in the tunnel SuperB Meeting, Isola d’Elba, May 31st – June 3rd, 2008

… schematic view of the injector in the tunnel SuperB Meeting, Isola d’Elba, May 31st – June 3rd, 2008

Cost estimate (with VAT) (based on “1 kly per 3 sections” configuration) SuperB Meeting, Isola d’Elba, May 31st – June 3rd, 2008 SYSTEM Unitary cost (M€) Total cost (M€) RF Power station ( kly + SLED + Mod + ssa) ≈ 0.95≈ 34 Accelerating structures≈ 0.2≈ 20 Waveguides & accessories ≈4.00 Vacuum system ( pumps, gauges, valves …) ≈4.00 Cooling system ≈2.00 LLRF & controls ≈2.00 Total estimated cost (VAT incl.) ≈ 66 M€ ≈ ≈ 10 M€ per GeV

Some conclusions ……. Room-temperature linac GHz, with SLAC-type acc. Structures 60 MW peak RF power sources Damping Ring for positrons e+ 3 GeV SLC-polarized gun (or SLC-like)

Topics to be analyzed in more detail ✦ D.R. extraction-injection process: kickers and timing ✦ Electron Gun: bunch charge …. re-use the SLC gun or develope a new one ? re-use the SLC gun or develope a new one ? ✦ Support from SLAC: … 1.2 GeV SLC D.R. … transfer lines ….. … transfer lines ….. …. positron converter… …. positron converter… … accelerating structures … accelerating structures ? SuperB Meeting, Isola d’Elba, May 31st – June 3rd, 2008