STATUS OF THE THOUGHTS ABOUT THE INJECTION SYSTEM

STATUS OF THE THOUGHTS ABOUT THE INJECTION SYSTEM (oct. 2009) # Injection process in 3 phases, to avoid simultaneous acceleration of high-charge e- bunches and damped e+ bunches in the linac B. # No fast kickers required # Rings filled every 60 msec (16. 66 Hz) e- DR A GUN SHB B L - 0. 8 Ge. V 5. 7 Ge. V e+ DR R. Boni, S. Guiducci, M. Preger, J. Seeman, PS C 0. 1 Ge. V D 0. 8 Ge. V > 4 Ge. V e> 7 Ge. V e+

STATUS OF THE THOUGHTS ABOUT THE INJECTION SYSTEM t 1 -------- e- injection DR e. P dc P P P DC P t 2 = t 1 + 20 msec -------- e+ production high charge e- bunches P dc DR K t 3 = t 1 + 40 msec -------- e+ injection P P DC K DR P P e+

STATUS OF THE THOUGHTS ABOUT THE INJECTION SYSTEM TIMING t 1 t 2 t 3 20 msec e- Inj. (°) e- Inj. e+ Inj. e+ prod. (°°) e+ prod. e+ Inj. e+ prod. (°°) e+ Inj. Filling injection rate: 60 msec (i. e. @ 16. 666 Hz) (°) e- DR storage time = 60 msec (°°) e+ DR storage time = 80 msec e+ prod. (°°)

STATUS OF THE THOUGHTS ABOUT THE INJECTION SYSTEM LATEST PROPOSAL FROM IN 2 P 3 GROUP (A. Variola & c. ) # They made simulations that are presented apart (see Variola slides) # Re-circulation not necessary; rings injection rate: 40 msec 500÷ 600 Me. V by-pass MATCHING They claim it is possible to produce enough positrons at much lower energy with a careful design of the matching system (focusing+capture section) after the target CAPTURE SECTION # TARGET To perform e-/e+ conversion at lower energy, i. e. 500÷ 600 Me. V instead of 3 Ge. V GUN-BUNCHER # DR DR e- 4 Ge. V e+ 7 Ge. V

STATUS OF THE THOUGHTS ABOUT THE INJECTION SYSTEM recirculated linac no-recirculation, low energ. convers. Inj. rate 16. 66 Hz (60 ms) Inj. rate 25 Hz (40 ms) L = Lo • e(-t/180) “lifetime 3 min. ” filling time ≈ 15 sec (5 bunches/shot) filling time ≈ 10 sec (5 bunches/shot) L/Lo = 0. 92 L/Lo = 0. 946 i/io = [L/Lo]1/2 = 0. 97 Δn+ = 2. 2 • 109 Δn+ = 1. 65 • 109 positrons/bunch at linac output SLAC polarized electron source 7 x 1010 electrons in 1 nsec q ≈ 11 n. C I ≈ 11 A