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A New MIRF System. David Wildman Alex Chen, Zubao Qian, Vincent Wu March 16 , 2005. Outline. Specifications Beam Loading and Stability Cavity Design Mafia Simulations Costs Conclusions. Specifications. Intensity of 1.5E14 per MI cycle Maximum ramp rate of 305 GeV/s
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A New MIRF System David Wildman Alex Chen, Zubao Qian, Vincent Wu March 16 , 2005
Outline • Specifications • Beam Loading and Stability • Cavity Design • Mafia Simulations • Costs • Conclusions wildman - Proton Driver Director's Review
Specifications • Intensity of 1.5E14 per MI cycle • Maximum ramp rate of 305 GeV/s • Cavity peak voltage of 300 kV • 18 RF stations - same as current system • Frequency sweep: 52.814 MHz to 53.104 MHz wildman - Proton Driver Director's Review
Beam Loading • Both transient and steady-state beam loading are proportional to the cavity shunt impedance, Rs, divided by the cavity Q. • Rs/Q only depends on the cavity geometry • For a coaxial quarter wave resonator, Rs/Q can be adjusted by changing the characteristic impedance of the line • The new RF cavity will have 4x smaller Rs/Q • Rs/Q reduced from 104 to 25. • This will enable us to achieve 4x the present intensity with the same beam loading effects we see today. wildman - Proton Driver Director's Review
Beam Stability • For a detuned cavity without feedback, the RF system reaches the Robinson instability limit when the power dissipated in the cavity equals the power being delivered to the beam. • For our case, the maximum power delivered to the beam will be 407 kW/cavity. • The maximum power dissipation in the cavity is chosen to be ~ 450 kW. • Guaranteeing beam stability without any feedback is the most conservative design. wildman - Proton Driver Director's Review
System Specifications • Rs/Q = 25, low Z transmission line • Rs/Q = 100 kΩ, Q = 4000 from copper coated stainless construction. • Perpendicularly biased garnet tuners • Present RF system will be driver for new system. • Power tetrode: CPI Eimac 8973 (1MW) or Thales TH525 (1.5 MW) wildman - Proton Driver Director's Review
New RF Cavity wildman - Proton Driver Director's Review
New RF Cavity wildman - Proton Driver Director's Review
Simulation Model for Main Injector New Cavity with TunerVincent Wu (MI Dept) Blue: copper Teal: stainless steel Green: ceramic window Red: ferrites wildman - Proton Driver Director's Review
Tuning Range vs. Tuner CouplingVincent Wu (MI Dept) Ferrite: ’=13.5 ’=1.22.5 wildman - Proton Driver Director's Review
Cost per RF Station • Cavity - $150k • Amplifier - $300k • 2 MW dc supply - $500k • Controls - $50k • Installation - $100k • Cost per station - $1.1M • Total cost for entire RF system - $20M wildman - Proton Driver Director's Review
CONCLUSIONS • Conservative design for beam stability • Total cost ~ $20M excluding civil, utilities, and contingency • The next step -- build a prototype cavity and amplifier wildman - Proton Driver Director's Review