arXiv subjects

Giuseppe Lerner

Publications and source records attributed to Giuseppe Lerner.

5 recordsLinked to original sources

arXiv2026

Beam Loss Consequences

The operation of high-energy and high-intensity particle accelerators inevitably leads to the loss of a fraction of beam particles, either through controlled processes or accidental events. This article builds on a first lecture on particle-matter interactions to review the main beam loss mechanisms in high-energy and high-intensity accelerators and their implications for safe and efficient operation. It discusses the resulting risks of equipment and material damage, radiation effects on electronics, and radiation-protection hazards. The focus is on beam losses in hadron accelerators, with particular emphasis on the Large Hadron Collider at CERN, while also addressing proposed future facilities such as the Future Circular Collider and muon colliders.

physics.acc-ph↗

arXiv2026

Particle-Matter Interactions

This lecture reviews the principles of particle-matter interactions, providing the essential physics background required to understand beam loss mechanisms in high-energy accelerators and their associated implications. The main interaction processes of photons and charged particles are introduced, together with an overview of nuclear reactions. The lecture then addresses electromagnetic and hadronic showers, which play a central role in particle-matter interaction physics. Following a brief overview of Monte Carlo simulation tools, with emphasis on FLUKA, the lecture concludes with a detailed examination of a representative LHC-type radiation shower.

physics.acc-ph↗

arXiv2026

X-ray reflection: a FLUKA model and its application in the design of synchrotron light beamlines and CERN's Future Circular Collider

Relying on atomic scattering factors from evaluated databases, a new model for the reflectivity of x rays on solid surfaces has been developed for FLUKA v4-6.0. This model accounts for the variation of reflectivity as a function of the photon energy, its incidence angle, and linear polarisation; surface roughness effects are also taken into account. FLUKA reflectivities agree well with those obtained from state-of-the-art codes used for the characterization of optical devices, both for homogeneous solids and for multilayer mirrors. This new capability renders FLUKA a nearly one-stop shop for synchrotron radiation simulations: emission from bending magnets and wigglers, photon transport and interaction, electromagnetic (and hadronic when applicable) shower development in complex geometries, as well as x-ray reflection at designated solid surfaces can now be all accounted for in a single FLUKA run. This streamlined FLUKA simulation workflow greatly simplifies the plethora of simulation tools that Monte Carlo practitioners previously needed to rely on. Two application scenarios of this new reflectivity model are showcased: first, the use of a multilayer mirror to deflect x rays from an optical hutch onto an experimental hall at the MINERVA beamline of the ALBA synchrotron and, second, the assessment of the photon flux near the interaction point at the CERN's Future Circular Collider (in its electron-positron stage) as a result of upstream x-ray reflections.

physics.acc-ph↗

arXiv2026

Design and modeling of a liquid-lead dump concept for beamstrahlung radiation absorption in the CERN Future Circular e$^+$e$^-$ Collider

The electron-positron Future Circular Collider (FCC-ee) being developed at CERN will generate intense beamstrahlung radiation, thus requiring photon absorbers downstream of the interaction points. This work presents the conceptual design of flowing-liquid-lead absorbers capable of dissipating around 370 kW of photon power, with a mean photon energy of 62 MeV. Two configurations are investigated: an inclined-flow geometry, developed to increase the photon interaction length to maximize absorption, and a compact upstream slope with an additional pool, in which a free-surface lead flow intercepts the power peak before a downstream pool dissipates the remaining load. Photon-matter interactions are modeled using Monte Carlo simulations in fluka, while conjugate heat-transfer and free-surface dynamics are analyzed through computational-fluid-dynamics simulations using ansys fluent. Design refinements are introduced based on the simulated thermal and hydraulic performance and to mitigate secondary effects such as photon backscattering. Both configurations demonstrate stable operation within the 300 kg/s flow limit and maintain liquid-lead and structural temperatures within the operational range of 450--500 $^{\circ}$C. The results establish circulating liquid lead as a feasible and thermally robust baseline technology for beamstrahlung absorption in FCC-ee.

physics.acc-ph↗

arXiv2023

Energy deposition studies for the Upgrade II of LHCb at the CERN Large Hadron Collider

The Upgrade II of the LHCb experiment is proposed to be installed during the CERN Long Shutdown 4, aiming to operate LHCb at 1.5x$10^{34}cm^{-2}s^{-1}$ that is 75 times its design luminosity and reaching an integrated luminosity of about $400 fb^{-1}$ by the end of the High Luminosity LHC era. This increase of the data sample at LHCb is an unprecedented opportunity for heavy flavour physics measurements. A first upgrade of LHCb, completed in 2022, has already implemented important changes of the LHCb detector and, for the Upgrade II, further detector improvements are being considered. Such a luminosity increase will have an impact not only on the LHCb detector but also on the LHC magnets, cryogenics and electronic equipment placed in the IR8. In fact, the LHCb experiment was conceived to work at a much lower luminosity than ATLAS and CMS, implying minor requirements for protection of the LHC elements from the collision debris and therefore a different layout around the interaction point. The luminosity target proposed for the Upgrade II requires to review the layout of the entire insertion region in order to ensure safe operation of the LHC magnets and to mitigate the risk of failure of the electronic devices. The objective of this paper is to provide an overview of the implications of the Upgrade II of LHCb in the experimental cavern and in the tunnel with a focus on the LHCb detector, electronic devices and accelerator magnets.

hep-ex↗