shower simulations are essential for understanding and predicting the consequences of beam losses in high-energy proton and ion colliders. Shower simulations are routinely used at CERN for estimating the beam-induced energy deposition, radiation damage, and radioactivity in the Large Hadron Collider (LHC). Comparing these shower simulations against beam loss measurements is an important prerequisite for assessing the predictive ability of model calculations. This paper validates FLUKA simulation predictions of beam loss monitor (BLM) signals against BLM measurements from proton fills at 3.5 and 4 TeV and 208 Pb 82þ ion fills at 1.38A TeV. The paper addresses typical loss scenarios and loss mechanisms encountered in LHC operation, including proton collisions with dust particles liberated into the beams, halo impact on collimators in the betatron cleaning insertion, proton-proton collisions in the interaction points, and dispersive losses due to bound-free pair production in heavy ion collisions. Model predictions and measured signals generally match within a few tens of percent, although systematic differences were found to be as high as a factor of 3 for some regions and source terms.

No abstract

No abstract

In addition to high-energy hadrons, which include neutrons, protons, and pions above 20 MeV, thermal neutrons (ThNs) are a major concern in terms of soft error rate (SER) for electronics operating in the large hadron collider (LHC) accelerator at the European Organization for Nuclear Research (CERN). Most of the electronic devices still contain Boron-10 inside their structure, which makes them sensitive to ThNs. The LHC radiation environment in different tunnel and shielded areas is analyzed through measurements and FLUKA simulations, showing that the ThN 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, field-programmable gate arrays (FPGA), and Flash memories of different technologies are studied to derive the expected singleevent upset (SEU) rate due to ThNs, relative to the high-energy hadron contribution. We find that for the studied parts and most of the accelerator applications, ThNs 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, ThNs 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 ThNs are presented.

The Large Hadron Collider (LHC) at the European Organization for Nuclear Research (CERN) is the largest accelerator in the world, spanning a circumference of 26.7 km. During its operation, small fractions of the beams are being continuously lost. This leads to mixed-field radiation that might affect electronic equipment through both cumulative and single-event effects. This article considers the radiation environment during Run 2 (years 2015-2018) in the LHC arc sectors that constitute approximately 70% of the accelerator, housing a huge amount of electronics. There, the main magnets' configuration is periodic, and the main contributor to losses is the interaction of the beams with residual gas molecules, resulting in relatively low-radiation levels, as opposed to different parts of the LHC. However, as presented, there are locations where losses are no longer dominated by residual gas. In these locations, radiation levels are higher by up to more than two orders of magnitude and could, therefore, be problematic in terms of cumulative radiation effects on electronics. In this article, the dose measurements from beam loss monitors have been combined with the FLUKA simulation for the arc sectors in order to indirectly retrieve the residual gas densities and radiation profile under the magnet cryostats, at the equipment level, for the losses caused by residual gas. Estimations for the radiation levels in the arc sectors during the high-luminosity LHC era and potential implications for the electronics are discussed as well.