Abstract
| The Super Proton Synchrotron (SPS) is the second largest synchrotron at CERN and produces high-brightness beams for the Large Hadron Collider (LHC). Recently, the dilution kicker (MKDH) of the SPS beam dump system (SBDS) has demonstrated unanticipated behaviour under high beam brightness conditions. During the 2022 and 2023 beam commissioning, the MKDH, which is routinely pulsed at high voltage, was subjected to intensities of up to 288 bunches of 2·10¹¹ protons per bunch and bunch lengths as low as 1.5 ns. Under these conditions, all the SPS kickers and septa exhibited a rapid vacuum pressure rise and a significant temperature increase with the MKDH playing the dominant effect in restricting the maximum line density that can be attained. This paper presents the results of the collected data, emphasizes the dependence on beam parameters, and introduces a probabilistic model to illustrate the effect of MKDH conditioning observed to forecast the pressure behaviour. Finally, potential countermeasures and outlook are discussed. |