Ultra Low Emittance Light Sources

where R is the bend radius, and P the radiated power. This paper outlines the special issues for reaching subThe design of a synchrotron light source is essentially a nm emittance in a storage ring. Effects of damping matter of balancing the conflicting trade-offs (optimized wigglers, intra-beam scattering and lifetime issues, for Insertion Device (ID) beam lines) 161: dynamic aperture optimization, control of optics, and their interrelations are covered in some detail. The unique choices for the NSLS-I1 are given as one example. Emittance Circumference (C) WHAT'S KNOWN The first dedicated third generation light sources were 1IHor. Cost of Chromaticity Footprint commissioned in the early 80s, i.e., they have been optimized for over 20 years. Basically: 0 cost of . The horizontal emittance (isomagnetic lattice) is Operations given by (E[G~v])' F The main A lattice parameters Power Consumption are summarized (P) in 0 Tab. 1, E, [ n m ~ a d ] =7.84x103 . J,N; where values particular for the NSLS-I1 have been highlighted. where N , is the number of dipoles, J.r + J z = 3 , GLOBAL OPTIMIZATION The (natural) horizontal emittance originates from the equilibrium: damping tt diffusion of three different processes: radiation damping, quantum fluctuations, and Intrabeam Scattering (IBS). One can show that (fundamental limit is IBS): 1 E, -R 2 .P %[email protected] 'Work supported by U S . DOE, Contract NODE-ACOZ-98CH10886. Given the design goals and approach, challenges related to non-linear dynamics issues are: Medium energy: control of Touschek lifetlme and momentum aperture. 30 DBA cells: control of tune footprint. Control of impact of DWs and IDS -> include leading order nonlinear effects from DWs in the Dynamic Aperture (DA) optimizations. Optics requirements for IDS and top-up injection are contradictory: introduce alternating straights with highand low horizontal beta functions <-> reduced symmetry (30 -> 15). Lattice Parameters 3 GeV 791.5 m 500 mA ~ 5 " ~ s . . ., . .