By Giorgia Favia, Tobias Stadlbauer and Thomas Kramer for SY-ABT (CERN)
During YETS 2024/25 the third and fourth MKI Cool magnets for the HL-LHC were installed at Point 8, completing the upgrade of one entire injection point.
The LHC is equipped with two injection kicker (MKI) systems for deflecting the incoming particle beams onto the LHC’s orbits. Each system, located at Point 2 (MKI2) and Point 8 (MKI8), consists of four MKI magnets.
The MKIs employ a large amount of ferrite to generate the required pulsed field homogeneity and magnitude. Since the yoke is directly exposed to the beam it is susceptible to beam-induced heating. To mitigate this, the MKIs incorporate a 3-metre-long alumina chamber that provides mechanical support and electrical insulation for screen conductors. These conductors shield the yoke from high-frequency beam-induced effects.
At the higher beam intensities expected for the HL-LHC, the conventional beam screens are insufficient to provide the necessary reduction in beam coupling impedance to keep the beam induced heating at acceptable levels. This has led to a major upgrade: the MKICool project which features an improved Cr₂O₃ coated alumina chamber, the integration of a water cooled “RF damper” and other smaller performance improvements.
The first MKI Cool (MKI8D) was installed at Point 8 during EYETS 2022/23, followed by a second one (MKI8C) during EYETS 2023/24.
The ABT team, supported by CERN colleagues, has worked hard to ensure the timely preparation and installation of the third and fourth MKI Cool magnets at Point 8 during YETS 2024/25.
This is a major milestone as it completes the upgrade of an entire injection point. The full MKI upgrade will be completed during Long Shutdown 3.
Figure 2. Installation of fourth MKI Cool magnet during YETS 2024/25. Maximilien Brice / CERN