Luminosity measurements at CMS using DT Phase 2 Demonstrator

In Phase-2, CMS will rely on multiple detector systems and, in particular, DT Luminosity, this is the Synchronous histogramming of muon trigger primitives. In this phase hits from DT and RPC detectors will be combined to reconstruct muon track segments. The demonstrator system is equipped with 5 back-end boards. This report shows an analysis of several datasets recorded in 2023. Most of the analysis was performed for Fill 9062 (Stable Beams, 2452 colliding bunches). Background contributions such as type1 afterglow hits, cosmic and beam induced were analysed. Finally, the luminosity for one of the boards was computed

Updates on the Conceptual Design Study of the Magnets for the Muon Collider Storage Ring

The Muon Collider represents an exciting proposal for a post-LHC accelerator, capable of exploring higher-energy regions with greater power consumption efficiency compared to hadronic alternatives, while avoiding synchrotron radiation limitations inherent in electron colliders. This contribution will focus on the magnets for the Muon Collider storage ring. These magnets pose an unprecedented technological challenge: high magnetic fields are required to ensure the compactness of the ring, maximizing the number of muon beam passes through the interaction region and thereby increasing luminosity. Additionally, large apertures are essential to accommodate an adequate shielding system that keeps the thermal and nuclear loads induced by the beam within acceptable limits. Furthermore, minimizing straight sections is critical to avoid the radioactive hazard posed by collimated neutrino beams, necessitating the use of combined-function magnets (dipole + quadrupole and dipole + sextupole). The interaction region also presents extreme conditions that demand the development of magnets beyond the current state of the art. In this contribution, we will discuss the progress in the feasibility study of magnets for both the arc and the interaction region of the Muon Collider storage ring. Performance limits will be analyzed for dipoles and quadrupoles, taking into consideration constraints on mechanical stresses, margin on the load line, ease of the protection system and cost for ReBCO-based magnets. Finally, the most up-to-date conceptual designs of the arc dipole will be presented, comparing the strengths and challenges of the cos-theta and block coil layouts in terms of achieving of electromagnetic requirements, mechanical structure feasibility, and windability

Magnet System of the New Electron Cooler for the CERN Antiproton Decelerator (AD) Ring

A new electron cooler for the Antiproton Decelerator (AD) ring at CERN is under construction and will be installed in the next long shutdown (2026-2028) to replace the existing 40-year-old device. This paper presents the design of the new electron cooler’s normal conducting magnet system comprising three straight solenoid sections joined by two toroidal field sections. Compared to the existing electron cooler magnet system, the new magnet system gives a factor five improvement of cooling region field quality. The field correction scheme used to achieve this improvement will be discussed in detail. The upgrade has the potential to reduce the length of the electron cooling plateaus in the AD cycle and thereby increase the number of antiprotons available to CERN’s rich antimatter physics program

Metal as Insulation REBCO Racetracks Coils: Development, Fabrication, and Cryogenic Testing at CEA Paris-Saclay

CEA-Saclay started the development of Metal-as-Insulation racetrack coils in as part of the High Field Magnet (HFM) CERN program. This winding method aims to significantly reduce the amount of High Temperature Superconductor material required to achieve relatively high magnetic induction and associated forces. CEA’s objectives are to fabricate and test a small racetrack coil to benchmark numerical models with experimental data. The insulated coil counterpart, operating at lower current densities and targeting high fields, is studied by CERN as part of the HFM program. This paper focuses on the design, fabrication and quench tests at 4.2 K of two specific coils: a single racetrack coil and a double racetrack coil (DRT), each with 140 mm long straight part and 27 mm inner diameter. Both coils achieved very high overall current density (above 2300 A/mm2 ) and significant peak magnetic field on the conductor (8.5 T and 12.3 T respectively). A central magnetic field above 5 T was reached after a quench at 4.3 T in the DRT

Design Comparison of Four-Layer Full-Nb3_{3}Sn and Hybrid Nb3_{3}Sn/NbTi Cos-Theta Dipoles for the CERN High Field Magnet R&D Programme

The High Field Magnet (HFM) R&D; programme at CERN aims to find technological solutions for the construction of accelerator magnets to be installed in future post-LHC colliders. The Italian Institute for Nuclear Physics (INFN) and CERN are collaborating to design and fabricate a new four-layer cos-theta dipole able to achieve a bore field of 14T with at least 20% margin on the load-line. Two design options are under evaluation: a four-layer dipole entirely made of Nb$_{3}$Sn, and a hybrid configuration combining inner Nb$_{3}$Sn layers with outer NbTi layers. Both options are being assessed for feasibility as short models, with scalable design choices for longer magnet prototypes suitable for accelerator integration. This paper presents a comparative study of the performance of the two design options. The results provide insights into the trade-offs between performance, complexity, and protection constraints in the development of next-generation high-field dipole magnets. The Full-Nb$_{3}$Sn solution satisfies the HFM requirements, but the Hybrid solution is a promising, cost-effective alternative that can be considered for next-generation colliders

Toward a Reduced Helium Content Cryogenic Cooling Scheme at 4.5 K for CERN’s FCC-hh Accelerator

A conceptual design for cooling superconducting ac- celerator magnets operating at 4.5 K is proposed for the hadron- hadron configuration of the Future Circular Collider (FCC-hh). This is motivated by efforts to reduce helium inventory and energy costs, while ensuring compatibility with the tunnel structure envis- aged for FCC-ee, and providing a technically viable solution for the magnets. The study is carried out for the latest configuration of the FCC-hh machine, the so-called F14 scenario, that uses Nb3Sn superconducting magnets with an operational magnetic field of 14 T, for a centre-of-mass energy of 85 TeV with a magnetic filling scheme of 83%. The updated heat loads are presented, along with expected longitudinal and radial temperature gradients in the magnet structure. The move from 1.9 K operation, which makes extensive use of He II, towards 4.5 K using single-phase helium significantly reduces the overall cryogenic power consumption by 30%, and the machine’s helium inventory by 50%