Beam position correction in the Fermilab high energy linac

The Fermilab Linac has been upgraded by the replacement of four 201.25 MHz drift tube linac tanks with seven 805 MHz side-coupled cavity modules. The reduction in physical aperture of the side-coupled modules has made control of the transverse beam position a more important consideration. An algorithm has been implemented to achieve a global least-squares minimization of beam position errors. Under typical operating conditions the RMS error in the horizontal plane is reduced by a factor of 8 (from 0.54 mm to 0.07 mm) and in the vertical plane by a factor of 4 (from 0.59 mm to 0.14 mm).