The “Environmental” Challenges: Impact of Radiation on Machine Components

Abstract

The High Luminosity LHC upgrade poses demanding requirements in terms of energy deposition, in particular around the high luminosity experiments where the Inner Triplet elements and the separation dipole will be exposed to unprecedented levels of radiation, challenging their reliability and lifetime. Dedicated Monte Carlo studies have been conducted in order to characterize the debris-machine interaction and define a suitable shielding.Moreover, also the areas adjacent to the LHC tunnel, where the installation of electronics equipment is envisaged, will be significantly impacted. In this context, cumulative damage (Total Ionizing Dose and/or Non-Ionizing Energy Loss) and stochastic effects have to be taken into account in an appropriate Radiation Hardness Assurance strategy, including the specification of the radiation environment, required test and qualification procedures, and corresponding radiation monitoring.

Energy deposition studies in the LHCb insertion region from the validation to a step into the Hilumi challenge

“…5 is due to diffractive processes, where one interacting proton receives a limited angular kick and is subject to a slight energy loss, this way managing to leave the Long Straight Section (LSS). In the range between 500 GeV and 2 TeV, the fluence at the IP-face of the Q1 in IR8 is higher than the values published for IR1 and IR5 [36] due to the absence of the TAS absorber. As already introduced, the TAS absorber, installed in the high luminosity IRs, protects the first quadrupole and considerably reduces the absorbed power as well as the peak dose and power density in its coils.…”

“…The role of the LHCb and MBXWH field is emphasized by the comparison with the bottom panel, where no field is applied before entering the triplet. We note that this difference in the abundance of positive and negative pions is much less dramatic in IR1 and IR5 [36]. The low energy tail of the pink curve in Fig.…”

“…6, is not present in the case of IR1 and IR5 due to the shielding by the TAS. In addition, re-interactions in the TAS absorber itself cause the peak to be at a lower energy, namely around 500 GeV, and more pronounced than that observed in IR8 [36]. The spectra for neutrons and photons travelling inside the vacuum chamber are displayed in Figs 8-9.…”

“…For proton operation, radiation showers in the experimental IRs are dominated by inelastic nuclear interactions at the IP. Hence, this study doesn't include elastic interactions, whose products remain in the beam and are possibly intercepted by the collimation system [36]. Each inelastic collision at the IP may generate a large number of secondary particles, on average about 120 with 7 TeV beams.…”

“…Each inelastic collision at the IP may generate a large number of secondary particles, on average about 120 with 7 TeV beams. Due to decay of unstable particles, mainly neutral pions, already 5 mm away from the IP and without interacting with any material, the number of debris particles increases to about 155, of which 50% are photons and 35% are charged pions [36]. While the majority of these particles interacts in the experimental beam pipe and in the detector , the most energetic debris is scattered at small angles with respect to the beam direction.…”