2015 11 16 LHC Aperture Filtering

• Typical aperture file used by Collimation group does not have any aperture 'type' information, ie circular, elliptical, racetrack, lhcscreen.
• This makes it unsuitable really.
• Thick lattice aperture model on AFS optics v6.503 doesn't run as it has negative lengths (aperture placements -ve from IPs).
• In both cases, ~90% of information is in markers rather than name matching elements in magnetic lattice (despite being in MADX Tfs format).
• Many 0, and 10m entries that require filtering.
• From relatively detailed thick aperture I got to work and filtered 0 and 10m items, there are 33855 aperture definitions for B1.
• Of 33855, only 31954 are unique - ie duplicate markers.
• Even more confusingly, some duplicates at the exact same position have different aperture information.
• Require duplicate removal for accurate element splitting and matching to magnetic lattice.
• Example of duplicate apertures: