The Cornell Electron Storage Ring Test Accelerator program obtained from 2009 through 2017 ever-improving measurements
of a variety of sources of emittance growth limiting the performance of CESR and future low-emittance rings such as
the damping rings for linear colliders and high-brightness X-ray beam sources. The past year has witnessed
important advances in the mature analysis of the data sets, as well as major progress in the sophistication
of our understanding of the underlying physics by means of numerical modeling of electron cloud buildup.
The latter now includes the first detailed calculations of electron production mechanisms sourced by
interactions of synchrotron-radiation photons in the CESR vacuum chamber walls. This work is attracting
the attention of accelerator physicists at a number of facilities, particularly at CERN in Switzerland and
KEK in Japan, where electron cloud effects are important contributors to performance limitations at the LHC
and SuperKEKB storage rings. We describe this recent work and include quantitative assessments of
potential consequences for the upgrade of the Cornell High Energy Synchrotron Source to be commissioned
in November.