Magnetic modeling vs measurements of the dipoles for the JLAB 10 kw Free Electron Laser Upgrade

Magnetic measurements of the six families of dipoles for the infrared Free Electron Laser Upgrade at the Thomas Jefferson National Accelerator Facility (Jlab) are compared to the magnetic models on which their design is based. The magnets were designed in parallel by three organizations. They used ANSYS, Radia or Opera 3D as a 3D magnetic modeling program. Comparison of the discrepancies between model and magnet measurement is presented along with analysis of their potential causes. These dipoles operate in two field ranges. The injector/extractor dipoles operate around 0.05 T and the arc dipoles and optical Chicane dipoles operate between 0.22 to 0.71 T. All magnets are required to meet core field and field integral flatness to parts in 10/sup 4/ over their "good field" region.