Report from MD380: Nonlinear errors in experimental insertions and off-momentum dynamic aperture

Nonlinear errors in low-¯¤ insertions can have a significant impact upon the beam dynamics. In particular reductions in the LHC dynamic aperture of the order of 3 ¾nominal (105 turns) are expected due to the presence of such errors in IR1 and IR5 at ¯¤ = 0.4m. This represents a slight risk to 40 cm operation in 2016. More optimistically correction of nonlinear errors in experimental insertions has led to significant gains in luminosity production in other accelerators: a ¸ 4% increase in integrated luminosity per fill was achieved in RHIC from the correction of such errors. The nonlinear errors of the ATLAS and CMS insertions were therefore studied at top energy during machine development time in 2015. During one of these studies it was also possible to perform AC-dipole kicks at injection, which have indicated a reduction in dynamic aperture off-momentum.