The Argonne Superconducting Magnet FOP Polarized Proton Targets

A D. C. superconducting C-frame magnet for use with polarized proton targets has been assembled and tested at ANL. This magnet has a vertical field of 25 k Gauss, uniform to within 4 parts in 104 over a 10 cm diameter, 2 cm high cylinder located at the center of the magnet´s 10 cm high room temperature air gap. The magnet consists of two sets of coils each containing a main coil and a correction coil. Each set of coils is mounted on its own coil form and in its own liquid helium dewar with only a small bellow communication line between them. The field is shimmed by adjustment of the correction coil current and by mechanical adjustment of the position of the top set of coils relative to the bottom set.