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TY - CONF AU - Kain, V. AU - Alemany-Fernández, R. AU - Bartosik, H. AU - Cettour Cave, S. AU - Cornelis, K. AU - Cruikshank, P. AU - Ferreira Somoza, J.A. AU - Goddard, B. AU - Pasquino, C. ED - Koscielniak, Shane ED - Satogata, Todd ED - Schaa, Volker RW ED - Thomson, Jana TI - Identification and Removal of SPS Aperture Limitations J2 - Proc. of IPAC2018, Vancouver, BC, Canada, April 29-May 4, 2018 C1 - Vancouver, BC, Canada T2 - International Particle Accelerator Conference T3 - 9 LA - english AB - The CERN SPS (Super Proton Synchrotron) serves as LHC injector and provides beam for the North Area fixed target experiments. Since the 2016 run automated local aperture scans have been performed with the main focus on the vertical plane where limitations typically arise due to the flat vacuum chambers in most SPS elements. For LHC beams the aperture limitations with the present low integer tune optics also occur at locations with large dispersion. Aperture measurements in the horizontal plane using a variety of techniques were performed and showed surprising results, which could partially explain the unexpected losses of high intensity LHC beams at the SPS flat bottom. In this paper, reference measurements from 2016 are compared with the ones taken at the beginning of the run in 2017. Several aperture restrictions in the vertical plane could be found and cured, and a potential systematic restriction in the horizontal plane has been identified. The results of the measurements and the origin of the restrictions are presented in this paper, and the outlook for partial mitigation is discussed. PB - JACoW Publishing CP - Geneva, Switzerland SP - 709 EP - 712 KW - optics KW - vacuum KW - target KW - proton KW - injection DA - 2018/06 PY - 2018 SN - 978-3-95450-184-7 DO - 10.18429/JACoW-IPAC2018-TUPAF021 UR - http://jacow.org/ipac2018/papers/tupaf021.pdf ER -