The High-Luminosity Large Hadron Collider (HL-LHC) project aims at extending the operability of the LHC by another decade and increasing by more than a factor of ten the integrated luminosity that the LHC will have collected by the end of Run 3. This will require doubling the beam intensity and reducing the transverse beam size compared to those of the LHC design. The higher beam brightness poses new challenges for machine safety, due to the large energy of 700 MJ stored in the beams, and for beam stability, mainly due to the collimator contribution to the total LHC beam coupling impedance. A rich research program was therefore started to identify suitable materials and collimator designs, not only fulfilling impedance reduction requirements but also granting adequate beam-cleaning and robustness against failures. The use of thin molybdenum coatings on a molybdenum–graphite substrate has been identified as the most promising solution to meet both collimation and impedance requirements, and it is now the baseline choice of the HL-LHC project. In this work we present the main results of the coating characterization, in particular addressing the impact of coating microstructure on the electrical resistivity with different techniques, from Direct Current (DC) to GHz frequency range.

The High-Luminosity LHC Project aims to increase the integrated luminosity that will be collected by the Large Hadron Collider for the needs of the high energy physics frontier by the end of its Run 3 by more than a factor ten. This will require doubling the beam intensity, and in order to ensure coherent stability until the brighter beams are put in collision, the transverse impedance of the machine has to be reduced. As the major portion of the ring impedance is generated by its collimation system, several low resistivity jaw materials have been considered to lower the collimator impedance and a special collimator has been built and installed in the machine to study their effect. In order to assess the performance of each material we performed a series of tune shift measurements with LHC beams. The results show a significant reduction of the resistive wall tune shift with novel materials, in good agreement with the impedance model and the bench impedance and resistivity measurements. The largest improvement is obtained with a molybdenum coating of a molybdenum-graphite jaw. This coating, applied to the most critical collimators, is estimated to lower the machine impedance by up to 30% and the stabilizing Landau octupole threshold by up to 240 A after accounting for uncertainties of the model and other destabilising effects. A half of the overall improvement can be obtained by coating the jaws of a subset of 4 out of 11 collimators identified as the highest contributors to machine impedance. This subset of low-impedance collimators is being installed during the Long Shutdown 2 in 2019-2020.

Introduction: Pancreatic cancer (PC) is one of the most aggressive and lethal malignancies, calling for enhanced research. Pancreatic ductal adenocarcinoma (PDAC) represents 70–80% of all cases and is known for its resistance to conventional therapies. Carbon-ion radiotherapy (CIRT) has emerged as a promising approach due to its ability to deliver highly localized doses and unique radiobiological properties compared to X-rays. In vitro radiobiology has relied on two-dimensional (2D) cell culture models so far; however, these are not sufficient to replicate the complexity of the in vivo tumor architecture. Three-dimensional (3D) models become a paradigm shift, surpassing the constraints of traditional models by accurately re-creating morphological, histological, and genetic characteristics as well as the interaction of tumour cells with the microenvironment. Materials and Methods: This study investigates the survival of pancreatic cancer cells in both 2D and spheroids, a 3D model, following photon, proton, and carbon-ion irradiation by means of clonogenic, MTT, spheroid growth, and vitality assays. Results: Our results demonstrate that carbon ions are more efficient in reducing cancer cell survival compared to photons and protons. In 2D cultures, carbon-ion irradiation reduced cell survival to approximately 15%, compared to 45% with photons and 30% with protons. In the 3D culture model, spheroid growth was similarly inhibited by carbon-ion irradiation; however, the overall survival rates were higher across all irradiation modalities compared to the 2D cultures. Carbon ions consistently showed the highest efficacy in reducing cell viability in both models. Conclusions: Our research highlights the pivotal role of 3D models in unraveling the complexities of pancreatic cancer radiobiology, offering new avenues for designing more effective and precise treatment protocols.

Background and purpose: Particle therapy (PT), including proton (PRT) and carbon ion radiotherapy (CIRT), offers physical and biological advantages over photon radiotherapy (XRT), particularly for radioresistant tumours such as glioblastoma and osteosarcoma. However, systematic preclinical comparisons using physiologically relevant models remain limited.Material and methods: T98G (glioblastoma), Saos-2 and U2-OS (osteosarcoma) cells were cultured as two-dimensional (2D) monolayers and three-dimensional (3D) spheroids and irradiated with XRT, PRT or CIRT at 2, 4 or 6 Gy. Clonogenic survival, metabolic activity (PrestoBlue), invasion and spheroid growth kinetics were quantified. Relative biological effectiveness (RBE) was derived from survival data, and spheroid sections were analysed histologically (H&E).Results: CIRT induced the strongest cytotoxic and anti-invasive effects across all models. In 2D cultures, the surviving fraction at 2 Gy decreased from 0.62 to 0.69 after XRT to 0.16–0.28 following CIRT (RBE = 2.1–2.4 vs. 1.1 for PRT; p < 0.0001). 3D spheroids exhibited overall higher radioresistance, yet CIRT markedly reduced growth and invasion, lowering normalised indices to 0.52 ± 0.12 (T98G) and 0.58 ± 0.09 (Saos-2) at 6 Gy, while photons often promoted invasion (> 1.2; p < 0.001). RBE values in 3D reached 3.6–4.0. H&E staining confirmed dose-dependent architectural disruption, with carbon ions inducing extensive necrosis and cellular degeneration.Interpretation: This study introduces a robust 3D preclinical platform for radiobiological assessment of particle therapy. CIRT consistently overcame intrinsic and microenvironment-mediated resistance, outperforming photons and protons in suppressing viability, invasion and spheroid integrity, thus reinforcing the translational relevance of 3D models and the therapeutic promise of carbon ion therapy for resistant malignancies.

The CERN accelerator complex is undergoing an upgrade in order to meet the requirements of the High-Luminosity Large Hadron Collider (HL-LHC). One of the key needs is to increase the intensity of beams injected into the LHC from the current $1.15\times {10}^{11}$ to $2.3\times {10}^{11}{\mathrm{p}}^{+}/\mathrm{bunch}$. This requires a beam intensity at injection in the Super Proton Synchrotron (SPS), the last injector before the LHC, as high as $2.6\times {10}^{11}{\mathrm{p}}^{+}/\mathrm{bunch}$, given that a budget for losses of about 10% is included in the design. However, previous experience with high intensity beams suggests that the total amount of losses in the SPS can be even higher, causing an increased activation, faster aging, and consequent early failure of machine equipment, in addition to an increase in the requirements for preinjectors in order to still meet the HL-LHC target in spite of higher losses. In this paper, we propose a collimation system to be used with HL-LHC proton beams in the SPS in order to intercept and safely dispose of beam losses in ad hoc locations and therefore provide the machine with protection against activation and equipment aging. The design is based on a two-stage concept, where the primary stage intercepts particles that otherwise would be lost, and the secondary stage employing an absorber where lost particles are finally disposed of. Numerical simulations prove a cleaning efficiency of the proposed system of at least 80%, substantially reducing the spreading of particle losses around the machine. Furthermore, the performance of the collimation system has a low sensitivity to common machine errors, and the design is cost efficient, with minimal hardware changes.

In the context of the HITRI project and EuroSIG international collaboration, a carbon-ion gantry is being designed for possible installation at the National Center for Oncological Hadrontherapy (CNAO), Pavia, Italy. The design is based on superconducting (SC) magnet technology for the dipoles, in order to reduce gantry dimensions and weight. Unlike normal-conducting magnets, SC magnets are sensitive to local beam losses, which can lead to local energy deposition and potential quenches, thus inducing considerable gantry downtime. This contribution presents exploratory studies of energy deposition in the SC dipole magnets currently foreseen for the gantry. The studies are carried out by means of Monte Carlo simulations, using the code to characterize ruling factors such as beam spot size and impact angle. In this exploratory phase, simulations were carried out assuming simplified beam impact conditions.