The 2023 operation of the Large Hadron Collider (LHC) at CERN included a one-month-long run with fully stripped Pb ion beams, marking the first heavy-ion run since 2018, and delivering Pb ion collisions at an unprecedented center-of-mass energy of 5.36 TeV per nucleon pair. During this period, the radiation fields in the LHC tunnel have been measured by means of different radiation monitors, including Beam Loss Monitors (BLMs), RadMons, and distributed optical fiber dosimeters, with the primary goal of quantifying the radiation exposure of electronic systems. The radiation levels are driven by the Bound Free Pair Production (BFPP) and Electromagnetic Dissociation (EMD) processes taking place in all four interaction points, yielding significant radiation peaks in the Dispersion Suppressor (DS) regions of the tunnel. An overview of the radiation levels is presented in this contribution, with a special focus on the Insertion Region 2 (IR2) hosting the ALICE experiment, where a new collimator (TCLD) has been installed specifically for the ion run. The impact of radiation on the electronic systems and on the LHC availability during the run will also be discussed.

Bent crystals are a mature technology used in several applications at CERN, such as the crystal-assisted collimation system for LHC ion operation and reduction of losses during the slow extraction from the SPS by shadowing the electrostatic septum. In the future, it is planned to measure electric and magnetic dipole moments of short-lived particles with a double-crystal experiment in the LHC. To consolidate their strategic use, CERN has been equipped to produce in-house bent crystals. Each crystal is required to be fully validated before its installation by different techniques, such as metrology, X-ray diffractometry and characterization with beams. The latter can measure the bending angle, the torsion, and the channeling efficiency, which is related to crystal imperfections. In this contribution, we present the performance with beams of the first prototype bent crystals manufactured at CERN and tested during a measurement campaign in the North Area.