FLUKA Run 2 simulation benchmarking with beam loss monitors in the CMS forward region

The FLUKA simulation framework is a general purpose Monte Carlo software for nuclear physics applications. It is commonly used by the CMS collaboration to make estimates on radiation levels in the underground cavern and at specific detector locations. The accuracy of the CMS model geometry in FLUKA is of key importance for the reliability of the simulation results which are used by the collaboration for detector instrumentation, radiation monitoring and environmental protection. It contains simplified geometries and averaged material compositions for a simple and accurate representation of the CMS detector and the underground cavern. To verify the accuracy of the model, benchmark simulations against real measurement data are regularly performed, often by using data taken from radiation monitors in CMS. This report details a simulation benchmark study conducted with measurements of two ionization chambers used as beam loss monitors in the CMS forward zone inside the rotating shield

Inverted CERN School of Computing 2023

In this course the students can learn how to write platform agnostic code using Python (and some C). Some knowledge (~1 year experience) of these two languages is recommended. The lecture will focus on how Python can easily be combined with C for CPU and GPU programming, by exploiting the advantages of both languages. The goal is to introduce 3 Python libraries that are used at CERN (e.g. in modern multiparticle simulation frameworks): CFFI, CuPy and PyOpenCL. CFFI is a library for Python-C interfacing and CPU kernel execution. CuPy and PyOpenCL are libraries for kernel execution compatible with GPUs. Additionally, there will be a short review of heterogeneous programming and a comparison of the CUDA and OpenCL programming models. In a subsequent tutorial session the students will be able to play around with these Python libraries

Impact of bunch intensity asymmetry in colliders featuring strong beamstrahlung

An analytical investigation of beamstrahlung-induced blow-up in Gaussian beams with arbitrary dimensions is presented, using various approximations for the strength of the hourglass effect and crab waist scheme. The results, applied to the FCC-ee resonances, are compared with simulations and previous calculations, and relative luminosity values are also calculated. The stability of resultant conformations are analysed to rule out the existence of a flip-flop phenomenon in the longitudinal plane analogous to the well-known transverse counterpart. Implications for the top-up injection procedures are discussed, and a phenomenological model is proposed to study the transverse-longitudinal coupling in the blowup dynamics

Towards Beam-Beam Simulations for FCC-ee

The FCC-ee (Future Circular Collider) lepton collider is currently the most favored next generation research infrastructure project at CERN, aimed at studying properties of standard model particles with the highest precision ever. The chosen parameters of the machine yield unprecedented conditions which give rise to previously unseen dynamical effects during collisions. The exploration and understanding of these beam-beam effects is of crucial importance for the success of the FCC-ee feasibility study. To address this challenge, a new general purpose software framework for beam dynamics simulations is currently under development at CERN. This presentation will discuss the contributions to the software development related to beam-beam effects with benchmark studies and applications. Proceedings of the 65th ICFA Advanced Beam Dynamics Workshop on High Luminosity Circular e+e- Colliders, eeFACT2022, Frascati, ItalyLPA

Towards Beam-Beam Simulations for FCC-ee

The FCC-ee (Future Circular Collider) lepton collider is currently the most favored next generation research infrastructure project at CERN, aimed at studying properties of standard model particles with the highest precision ever. The chosen parameters of the machine yield unprecedented conditions which give rise to previously unseen dynamical effects during collisions. The exploration and understanding of these beam-beam effects is of crucial importance for the success of the FCC-ee feasibility study. To address this challenge, a new general purpose software framework for beam dynamics simulations is currently under development at CERN. This presentation will discuss the contributions to the software development related to beam-beam effects with benchmark studies and applications

Benchmarking of the Radiation Environment Simulations for CMS Experiment at LHC

Radiation Simulations group of the Beam Radiation Instrumentation and Luminosity Project of the CMS experiment provide for CMS radiation environment and radiation effects simulation and benchmarking of these calculations with CMS data and other data from LHC measuring devices. We present some results of such benchmarking and the reliability analysis of the simulation procedures for radiation environment calculations at the LHC

Selected advances in the accelerator design of the Future Circular Electron-Positron Collider (FCC-ee)

International audienceIn autumn 2023, the FCC Feasibility Study underwent a crucial “mid-term review”. We describe some accelerator performance risks for the proposed future circular electron-positron collider, FCC-ee, identified for, and during, the mid-term review. For the collider rings, these are the collective effects when running on the Z resonance – especially resistive wall, beam-beam, and electron cloud –, the beam lifetime, dynamic aperture, alignment tolerances, and beam-based alignment. For the booster, the primary concern is the vacuum system, with regard to impedance and effects of the residual gas. For the injector, the layout and the linac repetition rate are primary considerations. We discuss the various issues and report the planned mitigations