In earlier work related to the NSLS-II project we have outlined a control theory approach for the dynamic aperture problem. In particular, an algorithm for the joint optimization of the Lie generator and the working point for the Poincare map. This time we report on how the Lie generator provides guidelines on acceptable magnitudes for e.g. the intrinsic nonlinear effects from insertion devices, and the nonlinear pseudo-invariant can be used to optimize the dynamic aperture. We also show how a polymorphic beam line class can be used to study the parameter dependance and rank conditions for control of optics and dynamic aperture.
bengtsson@bnl.gov
BNL, Upton, Long Island, New York
BNL, Upton, Long Island, New York
MIT, Middleton, Massachusetts
A new high-brightness synchrotron light source (NSLS-II) is under design at BNL. The 3-GeV NSLS-II storage ring has a double-bend achromatic lattice with damping wigglers installed in zero-dispersion straights to reduce the emittance below 1nm. In this note, we present an overview of the impact of collective effects upon the performance of the storage ring. Subjects discussed include Touschek lifetime, intra-beam scattering, instability thresholds due to ring impedance, and use of a third-harmonic Landau cavity.
BNL, Upton, Long Island, New York
We present conceptual design of the NSLS-II injection system. The injection system consists of low-energy linac, booster and transport lines. We review the requirements on the injection system imposed by the storage ring design and means of meeting these requirements. We discuss main parameters and layout of the injection system components.
BNL, Upton, Long Island, New York
To further improve the polarized proton (pp) run collision luminosity in the Relativistic Heavy Ion Collider, correction of the horizontal two-third resonance is desirable to increase the available tune space. The third resonance driving term (RTD) is measured with the turn-by-turn (TBT) beam position monitor (BPM) data with AC dipole excitation. A first order RTD response matrix based on the optics model is used to on-line compensate the third resonance driving term h30000 while keeping other first order RTDs and first order chromaticities unchanged. The results of beam experiment and simulation correction are presented and discussed.
BNL, Upton, Long Island, New York
The beam lifetime in most medium-energy synchrotron radiation sources is limited by the Touschek effect, which describes the momentum transfer from the transverse into the longitudinal direction due to binary collisions between electrons. While an analytical formula exists to calculate the resulting lifetime, the actual momentum acceptance necessary to perform this calculation can only be determined by tracking. This is especially the case in the presence of small vertical apertures at insertion devices. In this case, nonlinear betatron coupling leads to beam losses at these vertical aperture restrictions. In addition, a realistic model of the storage ring is necessary for calculation of the equilibrium beam sizes (particularly in the vertical direction) which are important for a self-consistent lifetime calculation.