In addition to high-energy hadrons, which include neutrons, protons and pions above 20 MeV, thermal neutrons are a major concern in terms of Soft Error Rate (SER) for electronics operating in the Large Hadron Collider (LHC) accelerator at CERN. Most of the electronic devices still contain Boron-10 inside their structure, which makes them sensitive to thermal neutrons. The LHC radiation environment in different tunnel and shielded areas is analyzed through measurements and FLUKA simulations, showing that the thermal neutron fluence can be considerably higher than the high energy one, up to a factor of 50. State-of-the-art Commercial Off The Shelf (COTS) components such as SRAM, FPGA and Flash memories of different technologies are studied to derive the expected Single Event Upset (SEU) rate due to thermal neutrons, relative to the high-energy hadron contribution. We find that, for the studied parts and most of the accelerator applications, thermal neutrons are the dominating source of upsets with respect to the high energy particles yielding even to neglect the latter in some cases. Indeed, they can induce in electronics up to more than 90% of the total upsets. The estimation is performed also for ground level and avionic applications, and although in general thermal neutrons are not the main source of SER, in Flash memories they can play the same role as high energy neutrons. Related Radiation Hardness Assurance (RHA) considerations for the qualification of components and systems against thermal neutrons are presented.

The Super Proton Synchrotron (SPS) is the second largest accelerator at CERN where protons are accelerated between 16 GeV/c and 450 GeV/c. Beam losses, leading to the mixed-field radiation of up to MGy magnitude, pose a threat to the reliability of the electronic equipment and polymer materials located in the tunnel and its vicinity. Particularly in the arc sectors, where both main magnets and radiation sensors are periodically arranged, the Total Ionizing Dose (TID) is of concern for the front-end electronics of A Logarithmic Position System (ALPS). The SPS is equipped with multiple radiation detection systems such as Beam Loss Monitors (BLM), RadMons, and as of 2021, the Distributed Optical Fibre Radiation Sensing (DOFRS), that combined all together provide a very comprehensive picture of both the TID spatial distribution and its time evolution. Within this study, the overview of measured 2021 and 2022 TID levels is presented, together with the demonstration of capabilities offered by the different radiation monitors. The DOFRS, supported by the passive Radio-Photo Luminescence (RPL) dosimeter measurements, is used to assess the TID values directly at the electronic racks, which turned out to be reaching several tens of Gy per year, potentially affecting the ALPS lifetime.

The Upgrade II of the Large Hadron Collider beauty (LHCb) experiment is proposed to be installed during the CERN Long Shutdown 4, aiming to operate LHCb at $1.5\times {10}^{34}{\mathrm{cm}}^{-2}{\mathrm{s}}^{-1}$ that is 75 times its design luminosity [1] and reaching an integrated luminosity of about $400{\mathrm{fb}}^{-1}$ by the end of the High Luminosity LHC era. This increase of the data sample at LHCb is an unprecedented opportunity for heavy flavor physics measurements. A first upgrade of LHCb (Upgrade I), completed in 2022, has already implemented important changes of the LHCb detector and, for the Upgrade II, further detector improvements of the tracking system, the particle identification system and the online and trigger infrastructure are being considered. Such a luminosity increase will have an impact not only on the LHCb detector but also on the LHC magnets, cryogenics, and electronic equipment placed in the insertion region 8. In fact, the LHCb experiment was conceived to work at a much lower luminosity than ATLAS and CMS, implying minor requirements for protection of the LHC elements from the collision debris, and therefore, a different layout around the interaction point. The Upgrade I has already implied the installation of an absorber for the neutral particle debris (TANB). However, the luminosity target proposed for this second upgrade requires to review the layout of the entire insertion region in order to ensure safe operation of the LHC magnets and to mitigate the risk of failure of the electronic devices. The objective of this paper is to provide an overview of the implications of the Upgrade II of LHCb in the experimental cavern and in the tunnel with a focus on the LHCb detector, electronic devices, and accelerator magnets. This proves that the Upgrade II luminosity goal can be sustained with the implementation of protection systems for magnets and electronics. The electronics placed in the experimental areas and in the cavern needs to be protected to mitigate a single event effect risk, which may imply recurring downtime of the LHC. On the other hand, protection for the first quadrupole of the final focus triplet and for the separation dipole are needed to prevent their quench and to reach the desired lifetime. Moreover, the normal-conducting compensators require the installation of shielding to limit their head coil degradation.

An important upgrade has been deployed for the collimation system of the Large Hadron Collider (LHC) for lead-ion beams that are already planned to reach their high-luminosity target intensity upgrade in the ongoing LHC Run 3 (2022–2026). While certain effects like e-cloud, beam-beam, impedance, injection, and dump protection are relaxed with ion beams, halo collimation becomes an increasing challenge, as the conventional multistage collimation system is about two orders of magnitude less efficient than that for proton beams. Ion fragments scattered out of the collimators in the betatron cleaning insertion risk quenching the cold dipole magnets downstream and may represent performance limitations. Planar channeling in bent crystals has been proven effective for high-energy heavy ions. A crystal collimation system was integrated into the LHC as a baseline solution for collimation in the High-Luminosity LHC (HL-LHC) era. In this paper, simulation and measurement results demonstrating the observation of channeling of heavy-ion beams and improvement in collimation cleaning in the multi-TeV energy regime are presented. The efficiency of the collimation scheme foreseen for the HL-LHC is presented. The highlights of the collimation performance in 2023, when crystal collimation was successfully deployed operationally for the first time, are also presented.

The LHCb (Large Hadron Collider beauty) experiment at CERN LHC aims at achieving a significantly higher luminosity than originally planned by means of two major upgrades: the Upgrade I that took place during the Long Shutdown 2 (LS2) and the Upgrade II proposed for LS4. Such an increase in instantaneous and integrated luminosity with respect to the design values requires to reassess the radiation exposure of LHC magnets, cryogenics, and electronic equipment placed in the insertion region 8 (IR8) around LHCb. Monte Carlo simulations are a powerful tool to understand and predict the interaction between particle showers and accelerator elements, especially in case of future scenarios. For this purpose, their validation through the comparison with available measurements is a relevant step. A detailed IR8 model, including the LHCb detector, has been implemented with the fluka code. The objective of this study is to evaluate radiation levels due to proton-proton collisions and benchmark the predicted dose values against beam loss monitor measurements performed in 2018. Finally, we comment on the upcoming LHC run (Run 3, from 2022 to 2025), featuring a first luminosity jump in LHCb.