SHIMMING TECHNIQUES FOR THE ULTRAPRECISE MUON G-2 STORAGE-RING AT THEAGS

Major components are in an advanced state of construction for a 7 mete r radius 0.1 PPM Precision storage ring.1 Detailed techniques are plan ned for static shimming of the assembly to at least 10 PPM magnetic fi eld uniformity prior to the use of field correction coils. An air gap behind each ultra-pure iron pole piece strongly decouples the aperture field shape from the properties of the 1006 iron yoke. Iron wedges wh ose thickness varies across the width of the poles with slope of appro ximately 1/60 are used to eliminate the gradient produced by the C-mag net shape required for open access for the decay electron counter on t he inside radius of the storage ring magnet. These wedges are 10 cm in azimuthal length and can be radially adjusted for short wavelength fi eld adjustments. A horizontal motion of 50 mum effectively adjusts the 10 cm half-gap aperture by 1 mum (or 10 PPM). This and other techniqu es to adjust dipole, quadrupole, sextuple, etc. multipoles will be des cribed.