Application of a new scheme for passing through transition energy to the Fermilab Main Ring and Main Injector

Conference · Tue Jan 01 04:00:00 EST 1991

OSTI ID:5740964

MacLachlan, J A; Griffin, J E

In the vicinity of the transition energy of an ion synchrotron the longitudinal oscillation frequency drops and the motion becomes non- adiabatic; the result is emittance dilution. Furthermore, because the synchrotron oscillation is too slow to average particle energy gain, particles off the synchronous phase get to much or too little acceleration depending whether they lead or lag; therefore, momentum spread is increased. In this regime of rf focusing degrades beam quality. Directly J. Griffin has proposed eliminating the rf focusing near transition by flattening the rf waveform with a second or third harmonic component. The rf is phased so that all particles in the bunch are accelerated by the flattened portion, receiving just the acceleration required by the magnet cycle. We will show by concrete examples related to the Fermilab Main Ring (MR) and Main Injector (MI) that one can eliminate rf focusing sufficiently long before and after transition to reduce the maximum momentum spread and emmitance growth significantly. Additionally, the bunch has its maximum phase spread at transition so that the peak current and resulting microwave instability is mitigated, and the bunch above transition becomes a satisfactory match to an accelerating bucket.

• Research Organization: Fermi National Accelerator Lab., Batavia, IL (USA)
• Sponsoring Organization: DOE; USDOE, Washington, DC (USA)
• DOE Contract Number: AC02-76CH03000
• OSTI ID: 5740964
• Report Number(s): FNAL/C-91-131; CONF-910505--187; ON: DE91013675
• Country of Publication: United States
• Language: English

Related Subjects

43 PARTICLE ACCELERATORS
430200* -- Particle Accelerators-- Beam Dynamics
Field Calculations
& Ion Optics
ACCELERATORS
BEAM BUNCHING
BEAM DYNAMICS
BEAM EMITTANCE
BEAM INJECTION
CYCLIC ACCELERATORS
DIFFERENTIAL EQUATIONS
EQUATIONS
EQUATIONS OF MOTION
INSTABILITY
OSCILLATIONS
PARTIAL DIFFERENTIAL EQUATIONS
RF SYSTEMS
SPACE CHARGE
SYNCHROTRON OSCILLATIONS
SYNCHROTRONS