1. EMMA Cavity Update Emma Wooldridge 27/02/07

2. Requirements Initial Design Cavity Options & Optimisation Available Designs Future Work

3. Requirements 19 Cavities Run from multiple IOTs or klystrons Voltage ~ 135 – 200 kV Shunt Impedance ~ 3 MΩ Beam pipe radius 19 mm Length 110 mm flange to flange –76 mm internal width

4. Shunt Impedance P = Power V = Cavity Voltage R sh = Shunt Impedance

5. Initial Design The ELBE bunching cavity For use on EMMA the shunt impedance must be increased from 1.4 MΩ

6. Cavity Options Modified ELBE design Scaled PEP II design Something else?

7. Optimising the Design Change –Width A –Height B –Nose cone Penetration C Radius D Angle E (All done whilst keep the frequency at 1.3 GHz)

8. Effect of Cavity Width

9. Nose Cone Angle

10. ELBE Like Design Nose cones have been made smaller Corners have been chamfered

11. PEP II Like Design Nose cones shallower Shape is flattened out

12. New Design Torus shape High Shunt Impedance

13. Nose Cone Radius

14. Comparison Practical shunt impedance assumes 80% of theoretical value

15. Field on axis Voltage / V Distance / mm BPM at 97mm

16. Voltage / V BPM at 97mm

17. Distance / mm Voltage / V BPM at 97mm

18. Closest BPM approx. 97 mm away from cavity centre Maximum voltage from cavity on BPM is 1 V.

19. Further Work Include realistic beam tubes Investigate half re- entrant design Add Coupler Add Tuners – 5.5 MHz Could cavity HOMs be used as BPMs?