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The irradiation of the CMS Hadron Calorimeter (HCAL) subdetectors results in decreased signal output from the active materials as well as increased noise in the photodetectors used to read out the system. The HCAL has a dedicated calibration system used to monitor and correct for these effects and to help synchronise the timing of the subdetectors. The calibration system is described with a focus on the upgrades to the laser system, which has undergone significant changes since the end of Run 2 of the LHC in 2018. A new solid state laser has been installed and commissioned, and the optical setup for light distribution has been simplified. An upgrade to the laser trigger board has reduced the laser trigger jitter by an order of magnitude. A new system has also been developed to fire the laser, based on existing HCAL electronics. Future improvements to the system are also presented, including ongoing work on extending the system to include remote monitoring capabilities. 

The MUon proton Scattering Experiment (MUSE) at the PiM1 beam line of the Paul Scherrer Institute is simultaneously measuring the elastic scattering of electrons and muons from a liquid hydrogen target to extract the charge radius of the proton with both positive and negative beam polarities. In addition to providing precise data for addressing the proton radius puzzle, comparing the four scattering cross sections directly tests lepton universality, radiative corrections, and two-photon exchange effects for electrons and muons. In order to study radiative correction and get more precise incident lepton energy at the scattering vertex for the cross section measurements, MUSE uses a lead-glass calorimeter located at the downstream end of the beam line. This proceeding discusses the specifications and calibration process of the calorimeter detector. Data are compared to simulation to demonstrate the performance of the detector. 

FASER is searching for light, weakly-interacting particles at the Large Hadron Collider. The first search for Axion-like particles (ALPs) decaying to a photon pair using data collected in 2022 and 2023 was performed and successfully excluded regions not previously ruled out. To further reduce neutrino background, a new preshower detector will be installed by the end of 2024. The detector is based on a monolithic active pixel sensor in 130 nm SiGe BiCMOS, which will allow resolving the photon pairs interacting in the preshower detector. The final ASICs have been produced in May 2024 and are currently being validated.