Quasi-integrable optics for a small electron recirculator

Abstract

This paper describes the design and simulation of a proof-of-concept quasi-integrable octupole lattice at the University of Maryland Electron Ring (UMER). This experiment tests the feasibility of nonlinear integrable optics, a novel technique that is expected to mitigate resonant beam loss and enable low-loss high-intensity beam transport in rings. Integrable lattices with large amplitude-dependent tune spreads, created by nonlinear focusing elements, are proposed to damp beam response to resonant driving perturbations while maintaining large dynamic aperture [Danilov and Nagaitsev PRSTAB 2010]. At UMER, a lattice with a single octupole insert is designed to test the predictions of this theory. The planned experiment employs a low-current high-emittance beam with low space charge tune shift (~0.005) to probe the dynamics of a lattice with large externally-induced tune spread. Design studies show that a lattice composed of a 25-cm octupole insert and existing UMER optics can induce a tune spread of \sim 0.13. Stable transport is observed in PIC simulation for many turns at space charge tune spread 0.008. A maximum spread of dnu = 0.11 (RMS 0.015) is observed for modest octupole strength (peak 50 T/m^3). A simplified model of the system explores beam sensitivity to steering and focusing errors. Results suggest that control of orbit distortion to <0.2 mm within the insert region is essential. However, we see only weak dependence on deviations of lattice phase advance (<=0.1 rad.) from the invariant-conserving condition.

References in corpus (6)

• IOTA (Integrable Optics Test Accelerator): Facility and Experimental Beam Physics Program
• Nonlinear Accelerator Lattices with One and Two Analytic Invariants
• Explicit integration of the Hénon-Heiles Hamiltonians
• Single-Particle Dynamics in a Nonlinear Accelerator Lattice: Attaining a Large Tune Spread with Octupoles in IOTA
• Design of a nonlinear quasi-integrable lattice for resonance suppression at the University of Maryland Electron Ring
• Low Space-Charge Intensity Beams in UMER via Collimation and Solenoid Focusing

Cited by in corpus (5)

• Design of double- and multi-bend achromat lattices with large dynamic aperture and approximate invariants
• Rapid-Cycling Synchrotron for Multi-Megawatt Proton Facility at Fermilab
• Derivative-Free Optimization of a Rapid-Cycling Synchrotron
• Hamiltonian preserving nonlinear optics
• Sextupole reduction via chaos suppression at the National Synchrotron Light Source II