Improved Aperture Measurements at the LHC and Results from their Application in 2015

A good knowledge of the available aperture in the LHC is essential for a safe operation due to the risk of magnet quenches or even damage in case of uncontrolled beam losses. Experimental validations of the available aperture are therefore crucial and were in the past carried out by either a collimator scan combined with beam excitations or through the use of local orbit bumps. In this paper, we show a first comparison of these methods in the same machine configuration, as well as a new very fast method based on a beam-based collimator alignment and a new faster variant of the collimator scan method. The methods are applied to the LHC operational configuration for 2015 at injection and with squeezed beams and the measured apertures are presented.