Studies for Cesr-TA: A low-emittance test accelerator at the Cornell Electron Storage Ring

The International Linear Collider (ILC) is a proposed facility for studying collisions of electrons and positrons at 500 GeV (center of mass). The quality of the ILC's results will depend on its ability to reach the specified luminosity of 2 × 1032 cm-2/s. Damping rings provide the required low-emittance beams, but the specifications for the ILC damping rings are ambitious by current standards. Important questions regarding dynamic instabilities need to be answered before the ILC design is finalized.;The CESR Test Accelerator (CesrTA) plan would convert the Cornell Electron Storage Ring into a low-emittance damping ring with parameters comparable to the ILC damping ring. However, achieving those parameters requires understanding and compensation for the magnet misalignments that increase vertical emittance.;We present calculations and simulations that characterize misalignments based on currently available survey data, and show that the two are consistent. We describe an algorithm for compensating for the misalignments, and optimize the parameters of that algorithm for various levels of misalignment and beam detector resolution. The corrected vertical emittance is less than the 10 pm target of the CesrTA proposal.;We optimize the same correction algorithm for the ILC damping ring, and show that, for CESR-level misalignments and detector performance, we also achieve the desired vertical emittance of 2 pm.;Finally, we describe a new way of measuring dispersion at CESR (and potentially at the ILC) using RF phase-modulation and multi-turn orbit measurements. This technique is faster than the current technique used at CESR, and our measurements show that the dispersion measured with the two techniques are in agreement with one another.