1. The ISIS Dual Harmonic Upgrade The Council for the Central Laboratory of the Research Councils Andy Seville Joint Accelerator WorkshopMarch 28th, 2006

2. Add 2 nd Harmonic RF Component RF Phase → Dual Harmonic P Error → RF Phase → Single Harmonic Voltage → Enlarge Stable Region Optimise trapping Reduce Loss ISIS Dual Harmonic Acceleration 50% More Protons!

3. ISIS Dual Harmonic Acceleration The required Accelerating Field is given by V = Vo (sin  - .sin (2  +  ) ) The voltage on Cavity Gaps is V = -Vo sin (  ) + .Vo sin (2  +  ) where Vo and  are +ve.  and  chosen to minimise loss during injection, trapping and acceleration cycle

4. ISIS RF Systems - Overview 13kV pk at 12 1RF accelerating gaps +10kVpk at 8 2RF accelerating gaps

5. ISIS Dual Harmonic Acceleration Changing Bias Current changes inductance of ferrite & therefore resonant frequency of the cavity. Every 20ms:- InjectionExtraction Proton Energy70MeV800MeV Rotation Freq0.65 MHz1.55MHz 1RF Freq1.3 MHz3.1 MHz 2RF Freq2.6 MHz6.3 MHz Bias current200 A2000 A

6. 2RF System Schematic LPRF Controls: Amplitude, Phase & Cavity Tuning Driver Amplifier Anode Power Supply 2 nd Harmonic high power RF Frequency Law Summing Amplifier Frequency Law Generator Master Oscillator 1.3 MHz - 3.1 MHz Dipole Search Coil Beam Phase Loop Radial Loop Trim Function Bunch Length Loop Existing Fundamental RF System  Phase Shifter Super- period Phase Splitter To Other 2 nd Harmonic Cavity LPRF Systems Phase Modulator 2 RF Level Controller Func Gen. 2 nd Harmonic Cavity Voltage Loop Func. Gen Phase Detector (Cavity Lock) Cavity Lock LPF 2 RF Detector RF Limiters Phase Detector (Cavity Tune) 2 Gated Summing Amplifier Delay Unit RF Summing Amplifier Phase Networks 2 2 nd Harmonic Cavity Phase Loop 2 nd Harmonic Cavity Tuning Loop Digital Signal Processor 2 nd Harmonic Beam Compensation Loop Sum Electrode Func. Gen. Func. Gen. LPF Variable Delay Variable Gain Frequency Doubler 2.6 MHz – 6.2 MHz 2 nd Harmonic low power RF HPD Cavity Cavity Bias Regulator Low Voltage Power Supply Cavity Lock Servo Cavity Gap A Voltage Monitor Summing Amplifier Phase Modulation and Delay Chassis 1RF 2RF A single Burle 4648VI tetrode is used to drive the 2RF cavity Phase Loop ALC Loop Beam Compensation Loop Cavity Tuning Loop

7. PSU - Splat! + PSU Tripping + ISIS Schedule + Machine Downtime

8. 2RF Commissioning - Preliminary Results DHRF Acceleration beam intensity and beam loss (2 x 2RF Cavities) 93.5% 95%

9. Schematic of fundamental frequency and 2nd harmonic RF lock loop Var. 90  M. O. Phase Mod  az ±0  / 90  (  = 0  /-18  /- 36  ) Cavity Lock Phase Mod  Trim 1 RF. Cav.  Ref. 90  Cavity lock Phase Mod  Trim  Ref. Var.  Phase Mod Frequency Doubler Fundamental System 2RF System A B  az±45 Phase Mod  Det. 2 RF. Cav. Simulated by Cable Delay and Summing Amp

10. ISIS 2RF System Phase Modulation  2RF42RF52RF62RF8 Az Shift21.573.55109.5165.5 1RF Phase43147.1219331 2RF Phase86294.2438662 Phase offset for location of each system around ring

11. 0° 2RF4 -90° +90° 2RF5 8:1 reduction in combined gap volts (simulated!) (SP4+SP5) / (SP4-SP5) ISIS 2RF System Phase Modulation 200V 10kV

12. Dual Harmonic Pulses Animated Version? DHRF Acceleration with 3 x 2RF cavities Beam Pulses @ 0.2ms N - protons

13. Dual Harmonic Pulses Animated Version? DHRF Acceleration with 3 x 2RF cavities Beam Pulses @ 0.3ms N - protons

14. Dual Harmonic Pulses Animated Version? DHRF Acceleration with 3 x 2RF cavities Beam Pulses @ 0.4ms N - protons

15. Dual Harmonic Pulses Animated Version? DHRF Acceleration with 3 x 2RF cavities Beam Pulses @ 0.5ms N - protons

16. Dual Harmonic Pulses Animated Version? DHRF Acceleration with 3 x 2RF cavities Beam Pulses @ 0.6ms N - protons

17. Dual Harmonic Pulses Animated Version? DHRF Acceleration with 3 x 2RF cavities Beam Pulses @ 0.7ms N - protons

18. Dual Harmonic Pulses Animated Version? DHRF Acceleration with 3 x 2RF cavities Beam Pulses @ 0.8ms N - protons

19. Dual Harmonic Pulses Animated Version? DHRF Acceleration with 3 x 2RF cavities Beam Pulses @ 0.9ms N - protons

20. Dual Harmonic Pulses Animated Version? DHRF Acceleration with 3 x 2RF cavities Beam Pulses @ 1.0ms N - protons

21. Dual Harmonic Pulses Animated Version? DHRF Acceleration with 3 x 2RF cavities Beam Pulses @ 1.5ms N - protons

22. Dual Harmonic Pulses Animated Version? DHRF Acceleration with 3 x 2RF cavities Beam Pulses @ 2.0ms N - protons

23. Dual Harmonic Pulses Animated Version? DHRF Acceleration with 3 x 2RF cavities Beam Pulses @ 3.0ms N - protons

24. Dual Harmonic Pulses Animated Version? DHRF Acceleration with 3 x 2RF cavities Beam Pulses @ 4.0ms N - protons

25. Dual Harmonic Pulses Animated Version? DHRF Acceleration with 3 x 2RF cavities Beam Pulses @ 5.0ms N - protons

26. Dual Harmonic Pulses Animated Version? DHRF Acceleration with 3 x 2RF cavities Beam Pulses @ 6.0ms N - protons

27. Dual Harmonic Pulses Animated Version? DHRF Acceleration with 3 x 2RF cavities Beam Pulses @ 7.0ms N - protons

28. Dual Harmonic Pulses Animated Version? DHRF Acceleration with 3 x 2RF cavities Beam Pulses @ 8.0ms N - protons

29. Dual Harmonic Pulses Animated Version? DHRF Acceleration with 3 x 2RF cavities Beam Pulses @ 9.0ms N - protons

30. Dual Harmonic Pulses Animated Version? DHRF Acceleration with 3 x 2RF cavities Beam Pulses @ 9.5ms N - protons

31. Theta Phasing Results 2RF SP5 APS Current SP4, 5 & 6 accelerating Theta = 0 Theta APS Current (with beam) 5Apk APS Current (no beam) 7Apk 0°0° -72° 2RF SP5 APS Current SP4,5 & 6 accelerating Theta

32. Challenges Solve Anode PSU tripping problem Complete cavity phasing tests DHRF Acceleration with all 4 2RF cavities Run 2RF Cavities reliably Increase beam current!