Search

During some periods in its second physics run (2015-2018), the LHC has been operated with 208Pb⁸²⁺ ion beams at an energy of 6.37 ZTeV. The LHC is equipped with a betatron collimation system, which intercepts the transverse beam halo and protects sensitive equipment such as superconducting magnets against beam losses. However, hadronic fragmentation and electromagnetic dissociation of heavy ions in collimators generate off-rigidity particles, which can be lost in the downstream dispersion suppressor, putting the magnets at risk to quench. An accurate modelling of the beam-induced energy deposition in the collimation system and superconducting magnets is important for quantifying possible performance limitations arising from magnet quenches. In this paper, we compare FLUKA shower simulations against beam loss monitor measurements recorded during the 2018 208Pb⁸²⁺ run. In particular, we investigate fast beam loss events, which lead to recurring beam aborts in 2018 operation. Based on these studies, we assess the ability of the simulation model to reproduce the observed loss patterns in the collimation region and dispersion suppressor., Proceedings of the 13th International Particle Accelerator Conference, IPAC2022, Bangkok, Thailand

The CHARM High-energy Ions for Micro Electronics Reliability Assurance (CHIMERA) working group at CERN is investigating the feasibility of delivering high energy ion beams to the CHARM facility for the study of radiation effects to electronics components engineered to operate in harsh radiation environments, such as space or high-energy accelerators. The Proton Synchrotron has the potential of delivering the required high energy and high-Z (in this case, Pb) ions for radiation tests over the relevant range of Linear Energy Transfer of ~ 10 - 40 MeV cm²/mg with a > 1 mm penetration depth in silicon, specifically for single event effect tests. This contribution summarises the working group’s progress in demonstrating the feasibility of variable energy slow extraction and over a wide range of intensities. The results of a dedicated 6 GeV/u Pb ion beam test are reported to understand the performance limitations of the beam instrumentation systems needed to characterise the beam in CHARM., Proceedings of the 13th International Particle Accelerator Conference, IPAC2022, Bangkok, Thailand

The LHC heavy-ion program with 208Pb⁸²⁺ beams is foreseen to benefit from a significant intensity upgrade in 2022. A performance limitation may arise from ion fragments scattered out of the collimators in the betatron cleaning insertion, which risk quenching superconducting magnets during periods of short beam lifetime. In order to mitigate this risk, an alternative collimation technique, relying on bent crystals as primary collimators, will be used in future heavy-ion runs. In this paper, we study the power deposition in superconducting magnets by means of FLUKA shower simulations, comparing the standard collimation system against the crystal-based one. The studies focus on the dispersion suppressor regions downstream of the betatron cleaning insertion, where the ion fragment losses are the highest. Based on these studies, we quantify the expected quench margin expected in future runs with 208Pb⁸²⁺ beams., Proceedings of the 13th International Particle Accelerator Conference, IPAC2022, Bangkok, Thailand

The power deposited in dispersion suppressor magnets downstream of the Large Hadron Collider (LHC) betatron cleaning insertion is governed by off-momentum particles scattered out of the primary collimators. In order to mitigate the risk of magnet quenches during periods of short beam lifetime in future High-Luminosity (HL-LHC) operation, new dispersion suppressor (DS) collimators are considered for installation (one per beam). In this paper, we present FLUKA simulations for both protons and Pb ions at 7 TeV, predicting the power deposition in the DS magnets, including the new higher-field dipoles 11T which are needed to integrate the collimator in the cold region next to the cleaning insertion. The simulated power deposition levels for the adopted HL-LHC collimator configuration and settings are used to assess the quench margin by comparison with the present estimated quench levels., Proceedings of the 12th International Particle Accelerator Conference, IPAC2021, Campinas, SP, Brazil

After the High Luminosity (HL-LHC) upgrade, the LHC will be exposed to a higher risk of magnet quenches during periods of short beam lifetime. Collimators in the extraction region (IR6) assure the protection of magnets against asynchronous beam dumps, but they also intercept a fraction of the beam halo leaking from the betatron cleaning insertion. In this paper, we assess the risk of quenching nearby quadrupoles during beam lifetime drops. In particular, we present an empirical analysis of halo losses in IR6 using LHC Run 2 (2015-2018) beam loss monitor measurements. Based on these results, the halo-induced power density in magnet coils expected in HL-LHC is estimated using FLUKA Monte Carlo shower simulations., Proceedings of the 12th International Particle Accelerator Conference, IPAC2021, Campinas, SP, Brazil