PSB rf Foreseen limitations with 2 E13 p at 2 GeV PS TFB PSB rf Foreseen limitations with 2 E13 p at 2 GeV BASIC CONSIDERATIONS Present performance: 1E13p from 50 MeV to 1.4 GeV in 490 ms (1.2s cycle) New Goal: 2E13p from 160 MeV to 2 GeV in 325 ms (0.6s cycle). 0.9s and 0.6s cycle data obtained from Alan and José (actual MD values) 36% more energy increase in 66% of the initial time, means roughly an average* rf power multiplied by two (1.36/0.66) together with a 3% frequency increase. *Average means average during the acceleration itself; an increase of a super-cycle duty cycle needs to be taken into account for the power cooling system A. Blas PSB RF 2GeV 10/03/2010

PSB rf Foreseen limitations with 2 E13 p at 2 GeV PS TFB PSB rf Foreseen limitations with 2 E13 p at 2 GeV Implications for the PSB low-level rf: 1.4 GeV : FREV = 1.75 MHz, FS = 446 Hz (h1,8kV) 2 GeV : FREV = 1.81 MHz, FS = 256 Hz (h1,8kV) The increase of FREV has no impact on the beam control The increase of B (8671 -> 11273 Gauss) requires having a B train counter well dimensioned (>17 bits). The 0.6 s cycle is very likely to require a zero flat-top duration and thus a zero duration synchro (no theoretical problem but may be processing power limitations!?) The change of FS (1680 Hz at 160 MeV, 256 Hz at 2 GeV (h1/8kV)) might require loop parameters to be programmed as functions (not constant)… may be this already the case !? (to be checked with Maria-Elena) Short cycles might reduce the time reserved to download the rf parameters into the beam control system and calculate the GFA functions (to be checked with Maria-Elena and Andy) A. Blas PSB RF 2GeV 10/03/2010

PSB rf Foreseen limitations with 2 E13 p at 2 GeV PS TFB PSB rf Foreseen limitations with 2 E13 p at 2 GeV Implications for the PSB transverse feedback: Beam current multiplied by 2.07 => required power multiplied by 4.3 The increased beam rigidity (+ 30% from 1.4 to 2 GeV) doesn’t play a role except for blow-up purposes… nevertheless a multiplication by 8 of the power is foreseen! A. Blas PSB RF 2GeV 10/03/2010

PSB rf Foreseen limitations with 2 E13 p at 2 GeV PS TFB PSB rf Foreseen limitations with 2 E13 p at 2 GeV Compromise at low energy: High intensity high space charge must increase emittance (painting) must keep high acceptance => φS small (for same rf voltage) must prolong acceleration => good for dipole power supplies + good for rf power. To have a faster cycle => increase rf voltage… and the rf power by the same amount A. Blas PSB RF 2GeV 10/03/2010

PSB rf Foreseen limitations with 2 E13 p at 2 GeV PS TFB PSB rf Foreseen limitations with 2 E13 p at 2 GeV Summary: RF power is a function of the acceleration time: the longer the acceleration the lower the power RF power is a function of the beam current: the higher the current, the higher the required power. RF voltage is a function of the acceleration duration: the faster the acceleration, the higher the voltage for the same acceptance. We can either specify tough constraints for the rf power taking into account the most ambitious beam, or set lower constraints and foresee cycles lengths as a function of the intensity. A. Blas PSB RF 2GeV 10/03/2010

PSB rf Foreseen limitations with 2 E13 p at 2 GeV PS TFB PSB rf Foreseen limitations with 2 E13 p at 2 GeV What can be supplied to the task force: rf power specifications for the possible most demanding beam (2E13p, 2 GeV, 0.6 s) Lessen rf power specifications with cycle lengths as a function of the intensity (1.2 s for 2E13p, 2 GeV),(0.6 s for <1E13p, 2 GeV)… More specifically from Mauro: how could this be made Information needed: Max Bdot of the new power supply (likely to be > 35.7 G/ms = 27.5 (present max) * 11273/8671 A. Blas PSB RF 2GeV 10/03/2010

PSB rf Foreseen limitations with 2 E13 p at 2 GeV PS TFB PSB rf Foreseen limitations with 2 E13 p at 2 GeV New Requirements: 2E13 p per ring (maximum intensity injected from Linac 4) instead of 1E13p as presently. 2GeV maximum kinetic energy at extraction (1 and 1.4 GeV also available) Cycle durations: 1.2 , 0.9 and 0.6 s 1.2s => inj=C275, flat-top=C765, ej=C805 => acceleration=490ms, flat-top=40ms 0.9s => inj=C175, flat-top=C575, ej=C615 => acceleration=400ms, flat-top=40ms (info A. Findlay) 0.6s => inj=C46, flat-top=C389=ej => acceleration=343ms, flat-top=0ms (info J.L. Sanchez) A. Blas PSB RF 2GeV 10/03/2010

PSB rf Foreseen limitations with 2 E13 p at 2 GeV PS TFB PSB rf Foreseen limitations with 2 E13 p at 2 GeV 1.4 GeV parameters w LINAC 2 1.2 s cycle 0.9 s cycle 0.6 s cycle C inj 275 175 C start flat-top 765 575 600 C extraction 805 615 Acc. duration 490 400 325 Flat-top duration 40 Max Bdot 22 G/ms between C555 and C635 27.5 G/ms between C360 and C465 A. Blas PSB RF 2GeV 10/03/2010

PSB rf Foreseen limitations with 2 E13 p at 2 GeV PS TFB PSB rf Foreseen limitations with 2 E13 p at 2 GeV 160 MeV 1 GeV 1.4 GeV 2 GeV B [Gauss] 2311 6867 8671 11273 Frev [MHz] 0.992 1.67 1.75 1.81 γ 1.17 2.06 2.49 3.13 FS [Hz] h=1 / 8kV 1680 645 446 256 Beam current H1 value for 2E13p Dipolar field; Present power supply limitations: 1.2 T/s -> 2.7 T/s (max value) => 65 ms 2.7 T/s -> 0 T/s => 135 ms A. Blas PSB RF 2GeV 10/03/2010

Beam loading in cavities PS TFB Beam loading in cavities A. Blas PSB RF 2GeV 10/03/2010