Title :
Effects of enhanced chromatic nonlinearity during the AGS γ t-jump
Author :
Wei, J. ; Brennan, J.M. ; Ahrens, L.A. ; Blaskiewicz, M.M. ; Deng, D.-P. ; MacKay, W.W. ; Peggs, S. ; Satogata, T. ; Trbojevic, D. ; Warner, A. ; van Asselt, W.K.
Author_Institution :
Brookhaven Nat. Lab., Upton, NY, USA
Abstract :
The γt-jump designed to reduce the bunch self-field mismatch and intensity loss during the AGS transition crossing can cause significant orbit and lattice distortions and dramatically enhance chromatic nonlinear effects. Employing a low-intensity, small emittance proton bunch crossing transition with the γt-jump quadrupoles excited, we found that the nonlinear momentum-compaction factor α1 increases from 2.2 to about 90 in the presence of the γt-jump. On the other hand, this enhancement can be effectively suppressed by properly exciting the chromaticity sextupoles, reducing α1 from 90 to 16. The experimental measurement agrees well with computer simulations using MAD and TIBETAN
Keywords :
accelerator magnets; beam handling techniques; electromagnets; proton accelerators; storage rings; synchrotrons; γt-jump quadrupoles; AGS γt-jump; Alternating Gradient Synchrotron; MAD code; TIBETAN code; bunch self-field mismatch reduction; chromaticity sextupoles; computer simulations; enhanced chromatic nonlinearity; intensity loss; lattice distortion; nonlinear momentum-compaction factor; orbit distortion; small emittance proton bunch crossing transition; transition crossing; Computer simulation; Energy measurement; Extraterrestrial measurements; Laboratories; Lattices; Loss measurement; Nonlinear distortion; Phase measurement; Protons; Time measurement;
Conference_Titel :
Particle Accelerator Conference, 1995., Proceedings of the 1995
Conference_Location :
Dallas, TX
Print_ISBN :
0-7803-2934-1
DOI :
10.1109/PAC.1995.505873
