1. PSB magnetic cycle 160 MeV to 2 GeV with 2.5E13 protons per ring
PS TFB
PSB magnetic cycle 160 MeV to 2 GeV with 2.5E13 protons per ring
Specifications
2.5E13 p from 160 MeV to 2 GeV
Current in bending magnets < 2267 ARMS +10% = 2493 ARMS with 1.2 second cycle (no modification of the cooling circuit).
MPS model: L= 0.18H, R=0.5Ω, Umax=3600V, B/I=2.15G/A
Cavity voltage limited to 8 kV.
Longitudinal space charge effects taken into account
A. Blas
2 GeV magnetic cycle /05/2010

2. PSB magnetic cycle 160 MeV to 2 GeV with 2.5E13 protons per ring
PS TFB
PSB magnetic cycle 160 MeV to 2 GeV with 2.5E13 protons per ring
Simplifications
Pure h=1 acceleration
Inductive and resistive wall effect neglected (impedance value to be asked for, but practically assumed to be low !?). The inductive effect counteracts the space charge effect.
All these (pessimistic) simplifications lead to conservative figures
A. Blas
2 GeV magnetic cycle /05/2010

3. PSB magnetic cycle 160 MeV to 2 GeV with 2.5E13 protons per ring
PS TFB
PSB magnetic cycle 160 MeV to 2 GeV with 2.5E13 protons per ring
Longitudinal space charge effect
Total coupling impedance:
Z0 = 377 Ω
Parasitic voltage superimposed (each turn) to the accelerating voltage (space charge only):
Inductive and resistive wall neglected
Circular beam pipe approximation (real value to be checked for)
A. Blas
2 GeV magnetic cycle /05/2010

4. PSB magnetic cycle 160 MeV to 2 GeV with 2.5E13 protons per ring
PS TFB
PSB magnetic cycle 160 MeV to 2 GeV with 2.5E13 protons per ring
Longitudinal space charge effect
Parasitic voltage superimposed (each turn) to the accelerating voltage (space charge only):
A. Blas
2 GeV magnetic cycle /05/2010

5. PSB magnetic cycle 160 MeV to 2 GeV with 2.5E13 protons per ring
PS TFB
PSB magnetic cycle 160 MeV to 2 GeV with 2.5E13 protons per ring
Simulation 1: injection at 1.2 T/s, 8kV (- SC) bucket filled up to 80 % with 2.5E13p (0.77 eV.s instead of 1.02 as planned)
The acceleration lasts 470 ms with a 5 ms flat-top (490 ms presently)
A. Blas
2 GeV magnetic cycle /05/2010

6. PSB magnetic cycle 160 MeV to 2 GeV with 2.5E13 protons per ring
PS TFB
PSB magnetic cycle 160 MeV to 2 GeV with 2.5E13 protons per ring
Simulation 1: injection at 1.2 T/s, 8kV (- SC) bucket filled up to 80 % with 2.5E13p (0.77 eV.s instead of 1.02 as planned)
The acceleration lasts 470 ms with a 5 ms flat-top (490 ms presently)
A. Blas
2 GeV magnetic cycle /05/2010

7. PSB magnetic cycle 160 MeV to 2 GeV with 2.5E13 protons per ring
PS TFB
PSB magnetic cycle 160 MeV to 2 GeV with 2.5E13 protons per ring
Simulation 1: injection at 1.2 T/s, 8kV (- SC) bucket filled up to 80 % with 2.5E13p (0.77 eV.s instead of 1.02 as planned)
The acceleration lasts 470 ms with a 5 ms flat-top (490 ms presently)
A. Blas
2 GeV magnetic cycle /05/2010

8. PSB magnetic cycle 160 MeV to 2 GeV with 2.5E13 protons per ring
PS TFB
PSB magnetic cycle 160 MeV to 2 GeV with 2.5E13 protons per ring
Conclusion:
These simulations concerns h1 uniquely, for a single harmonic acceleration made as fast as possible with a 8 kV h1 cavity and a beam emittance of 0.77 eV.s (80% of the 8 kV-SC bucket at injection) instead of the 1.02 eV.s beam planned at first.
The rf h1 cavity needs to supply 6 A of “accelerating current” (3 A presently available).
The MPS with a voltage limited to 3600 V is not fast enough to be compatible with a 1.2 s cycle.
Even if the MPS voltage is increased, with the h1 cavities limited at 8 kV, its RMS current will go above the limit of 2493 A
A. Blas
2 GeV magnetic cycle /05/2010

9. PSB magnetic cycle 160 MeV to 2 GeV with 2.5E13 protons per ring
PS TFB
PSB magnetic cycle 160 MeV to 2 GeV with 2.5E13 protons per ring
To be done:
Make simulations with new “realistic” values for the MPS max voltage (>3600V) and the max RMS current (> 2490 A).
A. Blas
2 GeV magnetic cycle /05/2010