Combined panofsky quadrupole & corrector dipole

Two styles of Panofsky Quadrupoles with integral corrector dipole windings are in use in the electron beam line of the free electron laser at Jefferson Lab. We combined steering and focusing functions into single magnets, adding hundreds of Gauss-cm dipole corrector capability to existing quadrupoles because space is at a premium along the beam line. Superposing a one part in 100 dipole corrector field on a 1 part in 1000, weak (600 to 1000 Gauss) quadrupole is possible because the parallel slab iron yoke of the Panofsky Quadrupole acts as a window frame style dipole yoke. The dipole field is formed when two electrically floating "current sources", designed and made at JLab, add and subtract current from the two opposite quadrupole current sheet windings parallel to the dipole field direction. The current sources also drive auxiliary coils at the yoke's inner corners that improve the dipole field. Magnet measurements yielded the control system field maps that characterize the two types of fields. Field analysis using TOSCA, construction and wiring details, magnet measurements and reference for the current source are presented.