Data Taking and Analysis
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To date the quantative information on electron cloud trapping has been obtained
from measurements of 5.3 GeV positron bunch trains in which the number of bunches in a train, the bunch population and the bunch spacing has been varied. Initial data-taking will repeat these studies in order to characterize the new synchrotron radiation environment and the performance of the improved detector. In addition, we will be able for the first time to vary the magnetic field strength in the quadrupole by compensating it with a nearby quadrupole. We will also be able for the first time to make each of these measurements with an electron beam. The synchrotron radiation photon scattering and cloud buildup models which have been validated with the measurements to date predict that signals of comparable magnitude (+- a factor two) will be observed at the new detector position not only for electron bunches of similar population, but also at 2.1 GeV (nominal field strength 2.0 T/m) as well as at 5.3 GeV (nominal field strength 3.4 T/m). 

The time-sliced particle-in-cell cloud buildup and electron tracking numerical model, which includes photoelectron and secondary electron models as well as detector response functions has proved essential in understanding the complicated relationship between the observed signals and the cloud spatial and time structures. Development of modeling for the detector with improved azimuthal coverage will be necessary. Of particular interest will be the opportunity to validate the highly nonlinear relationship between signals and cloud density as a function of bunch population indicated by the modeling of existing measurements and predicted for the measurements proposed here.