Precision Magnetic Measurements used for the Design of the Stanford Two-Mile Linear Accelerator Transport Systems

In order to utilize the electron beam of the Stanford two-mile accelerator most effectively, an elaborate beam switchyard will be used. Two basic components constitute the switchyard: a switching magnet and two deflecting transport systems. A precision deflection magnet system containing several dc magnets and quadrupoles will bend and momentum-analyze the electron and positron beams. This paper discusses the methods and techniques used in making high-precision magnetic measurements in dc and multipole magnetic fields. The requirements for the accuracy of field measurements are deduced from the beam optics of the transport systems. Special measurements and instruments used in these measurements will be discussed in detail, and the results of these measurements will be related to the optical properties of the particle beams. Special measurements in multipole magnets, such as the location of the magnetic center, the magnetic coordinate system, multipole content, effective length, and different methods of making such measurements, will be discussed.