Plans for nonlinear optics experiments at the University of Maryland Electron Ring include a distributed octupole lattice which may meet the conditions for quasi-integrable orbits in a format congruous with an underlying FODO structure. We discuss simulation results and baseline beam measurements to predict the performance and feasibility of this lattice.
Preparations are well underway at UMER, in preparation for quasi-integrable nonlinear octupole lattice experiments. Here we discuss the plans and baseline measurements for the “N4 lattice,” an attempt at implementing the NIO theory in a format that can be easily mated with the UMER structure. In this scheme, 4 octupole elements are installed in 4 quadrants of the ring. We aim to obtain beam phase advance of 2π between each octupole. This is possible because of the UMER operating mode known as “Alternative Lattice,” which has a nominal tune of 3.6, close to the 4+δ lattice desired for octupole lattice (where δ is related to the integrated length of octupoles). The Alternative Lattice uses half the number of quadrupoles as the standard lattice, where the beam envelopes are approximately equal at the middle of the FODO cell. Conveniently, empty mounts at these exact locations in the beam line can be used to house printed circuit octupoles. Dynamic aperture calculations with the matrix tracking code Elegant show better performance for the N4 lattice than for other permissible arrangements. Elegant and WARP calculations are in use to predict the Hamiltonian conservation. Approximations to the quasi-integrable theory may reduce the performance of this system, and the experiments will be challenging due to the necessary proximity to an integer resonance band. All this work is in addition to the focus on a “single-channel” quasi-integrable experiment.
** Funding for this project and travel is provided by DOE-HEP, NSF GRFP and NSF Accelerator Science Program
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