  We report on the design, deployment and signal analysis for shielded button
electrodes sensitive to electron cloud buildup at the Cornell Electron Storage
Ring. These simple detectors, derived from a beam-position monitor electrode
design, have provided detailed information on the physical processes underlying
the local production and lifetime of electron densities in the storage ring.
Digitizing oscilloscopes are used to record electron fluxes incident on the
vacuum chamber wall in 1024 time steps of 100 ps or more. The fine time steps
provide a detailed characterization of the cloud, allowing the independent
estimation of processes contributing on differing time scales and providing
sensitivity to the characteristic kinetic energies of the electrons making up
the cloud. By varying the spacing and population of electron and positron beam
bunches, we map the time development of the various cloud production and
re-absorption processes. The excellent reproducibility of the measurements also
permits the measurement of long-term conditioning of vacuum chamber surfaces.
