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Explore the development and testing of advanced crab cavity systems to enhance particle collision efficiency, optimize phase control, and improve luminosity in high-energy particle accelerators. The project involves international collaboration and experimentation to refine phase control systems and minimize phase errors for optimized performance.
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Initiating the Crab System R&D Graeme Burt Lancaster University Philippe Goudket Daresbury Laboratory
Crab Cavity Team • Graeme Burt RA Lancaster Uni. • Amos Dexter SL Lancaster Uni. • Philippe Goudket RF Eng.Daresbury • Alexander Kalinin RF Eng.Daresbury • Carl Beard RF Eng.Daresbury • Mike Dykes RFGroup Leader Daresbury • Mike Poole (Work Package 5 Leader)
Crab Cavity work plan 2005 • Analysis of requirement. • Interact with international community on specification of crab cavity solution. • Design experiment to investigate phase control limitations. • Design of cavity for phase control experiment. Crab Cavity longer term work plan • Build and operate phase control system experiment. • Design experiment to test crab cavity phase control systems on test beam. • Beam testing of cavities and control system.
Finite crossing angles • The luminosity of a collision is reduced by a finite crossing angle. The beams are rotated for a effective head-on collision, by a crab cavity. Crab cavity Crab cavity Effective head-on collision finite crossing angle Tilted bunch
Transverse deflecting dipole mode • The dipole mode of an elliptical cavity can be used to transversely deflect the beam. Magnetic field lines of the dipole mode. • Beam into page through centre point • Field is uniform in the beam direction • Sinusoidal in time
KEK-B Crab Cavity • Crab Cavities are currently under test at the KEK-B B factory, these have less stringent phase stability and lower kicks required.
Transverse deflecting dipole mode • Magnetic Field as seen by front, middle, and back of the bunch as a function of position across the cavity. • (At any instant the magnetic field is uniform across the cavity)
Crab cavity operation For optimum cell length B = max field in crab cavity d = distance from cavity to interaction point field jitter between cavities gives differing bunch rotation
Transverse deflecting dipole mode • Magnetic Field as seen by front, middle, and back of the bunch as a function of position across the cavity for phase error.
Momentum mismatch Differential phase jitter causes the two bunches to have a height mismatch, which can significantly reduce luminosity or cause the bunches to miss. to ≠ 0 Δx to = 0 to = time bunch enters cavity d = distance to IP
Issues • Position of crab cavities • Type of crab cavity • Frequency of operation • How phase jitter affects luminosity? • How field stability affects luminosity? • Effect of wakefields i.e. cavity harmonics • Performance of phase control systems
Crab cavity phase control system • Fast phase adjust using a second klystron and fast phase difference. Diagram by J. Frisch
Crab cavity Phase stabilization Test System Diagram by J. Frisch