Automatic Local Aperture Measurements in the SPS

The CERN SPS (Super Proton Synchrotron) serves as LHC injector and provides beam for the North Area fixed target experiments. It is equipped with flat vacuum chambers to accommodate the large horizontal beam size required during transition crossing and slow extraction. At low energy, the vertical acceptance becomes critical with high intensity large emittance fixed target beams. Optimizing the vertical available aperture is a key ingredient to optimize transmission and reduce activation around the ring. Aperture measurements are routinely carried out after each shutdown. Global vertical aperture measurements are followed by detailed bump scans at the locations with the loss peaks. During the 2016 run a tool was developed to provide an automated local aperture scan around the entire ring. This allowed to establish detailed reference measurements of the vertical aperture and identify directly the SPS aperture bottlenecks. The methodology applied for the scans will be briefly described in this paper and the analysis discussed. Finally, the 2016 SPS measured vertical aperture will be presented and compared to the results obtained with the previous method.