Collimation simulations for the FCC-ee Abramov, A.; Broggi, G.; Bruce, R. ...
Journal of instrumentation,
02/2024, Letnik:
19, Številka:
2
Journal Article
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Abstract
The collimation system of the Future Circular Collider,
operating with leptons (FCC-ee), must protect not only the
experiments against backgrounds, but also the machine itself from
beam ...losses. With a 17.8 MJ stored energy of the electron and
positron beams, they are highly destructive, and beam losses risk to
cause damage or a quench of superconducting elements. Accurate
collimation simulation tools and models are needed to design the
collimation system and optimize the collimation performance,
including magnetic tracking, synchrotron radiation and optics
tapering, as well as particle-matter interactions. As no existing
code was found that incorporated all these features, a new
simulation software tool has been developed. The tool is based on an
interface between a particle tracking engine, pyAT or Xtrack, and a
Monte-Carlo particle-matter interaction engine for collimator
scattering, BDSIM, which is based on Geant4. Results from a
simulation of edge scattering from a beam halo collimator in the
FCC-ee are presented to demonstrate the capabilities of the tool.
Hadron therapy installations are evolving towards more compact systems that require higher-quality beams for advanced treatment modalities such as proton flash and arc therapy. Therefore the accurate ...modelling of present and next-generation systems poses new challenges where the simulations require both magnetic beam transport and particle-matter interactions. We present a novel approach to building simulations of beam delivery systems at a level suitable for clinical applications while seamlessly providing the computation of quantities relevant for beam dose deposition, radiation protection assessment, and shielding activation determination. A realistic model of the Ion Beam Applications (IBA) Proteus® One system is developed using Beam Delivery Simulation (BDSIM), based on Geant4, that uniquely allows simulation using a single model. Its validation against measured data is discussed in detail. The first results of self-consistent simulations for beam delivery and equivalent ambient dose are presented. The results show that our approach successfully models the complex interactions between the beam transport and its interactions with the system for relevant clinical scenarios at an acceptable computational cost.
Creating and maintaining computer-readable geometries for use in Monte Carlo Radiation Transport (MCRT) simulations is an error-prone and time-consuming task. Simulating a system often requires ...geometry from different sources and modelling environments, including a range of MCRT codes and computer-aided design (CAD) tools. Pyg4ometry is a Python library that enables users to rapidly create, manipulate, display, debug, read, and write Geometry Description Markup Language (GDML)-based geometry used in MCRT simulations. Pyg4ometry provides importation of CAD files to GDML tessellated solids, conversion of GDML geometry to FLUKA and conversely from FLUKA to GDML. The implementation of Pyg4ometry is explained in detail in this paper and includes a number of small examples to demonstrate some of its capabilities. The paper concludes with a complete example using most of Pyg4ometry's features and a discussion of possible extensions and future work.
Program Title:Pyg4ometry
CPC Library link to program files:https://doi.org/10.17632/hngmhmh8cx.1
Licensing provisions: GPLv3
Programming language: Python, C++
External routines/libraries: ANTLR, CGAL, FreeCAD, NumPy, OpenCascade, SymPy, VTK
Nature of problem: Creating computer-readable geometry descriptions for Monte Carlo radiation transport (MCRT) codes is a time-consuming and error-prone task. Typically these geometries are written by the user directly in the file format used by the MCRT code. There are also multiple MCRT codes available and geometry conversion is difficult or impossible between these simulation tools.
Solution method: Create a Python application programming interface for the description and manipulation of Geant4 and FLUKA geometries, with full support for the direct reading and writing of their respective geometry description file formats. Form triangular meshes to represent geometric objects for both visualisation of the geometry and to enable the use of advanced mesh-based geometric algorithms. Triangular mesh processing algorithms allow the loading and use of Standard Triangle Language (STL) and CAD/CAM files. Converting from FLUKA to Geant4 requires algorithms to decompose solids to a set of unions of convex solids. Converting from FLUKA to Geant4 requires a number of steps including the replacement of infinite surfaces with finite solids and the automatic elimination of overlaps.
Beam Delivery Simulation (BDSIM) is a program that simulates the passage of particles in a particle accelerator. It uses a suite of standard high energy physics codes (Geant4, ROOT and CLHEP) to ...create a computational model of a particle accelerator that combines accurate accelerator tracking routines with all of the physics processes of particles in Geant4. This unique combination permits radiation and detector background simulations in accelerators where both accurate tracking of all particles is required over long range or over many revolutions of a circular machine, as well as interaction with the material of the accelerator.
Program Title: BDSIM
Program Files doi:http://dx.doi.org/10.17632/bzg5hc65h6.1
Licensing provisions: GNU General Public License 3
Programming language: C++, flex, bison
External routines/libraries: Geant4, CLHEP, ROOT, gzstream, CMake
Nature of problem: Simulate energy deposition and charged particle detector background in a particle accelerator originating from beam loss where particles may pass both through the vacuum pipe with magnetic and electromagnetic fields, as well as through the material of the magnets and accelerator itself. Simulate the passage of particles both through an accelerator and the surrounding material such as air. Do so in a sufficiently flexible way that a variety of accelerator configurations can be easily simulated.
Solution method: Automatic creation of a 3D Geant4 model from an optical description of an accelerator using a library of generic 3D models that are user extendable. Accelerator tracking routines, the associated fields and coordinates transforms are provided for accurate magnetic field tracking.
We present the development of a high power fiber laser system to investigate its suitability for use in a transverse electron beam profile monitor, i.e., a laserwire. A system capable of producing ...individual pulses up to 165.8±0.4μJ at 1036 nm with a full width at half maximum of 1.92±0.12ps at 6.49 MHz is demonstrated using a master oscillator power amplifier design with a final amplification stage in a rod-type photonic crystal fiber. The pulses are produced in trains of 1 ms in a novel burst mode amplification scheme to match the bunch pattern of the charged particles in an accelerator. This method allows pulse energies up to an order of magnitude greater than the steady-state value of 17.0±0.6μJ to be achieved at the beginning of the burst with a demonstrated peak power of 25.8±1.7MW after compression. The system is also shown to demonstrate excellent spatial quality with an M2=1.26±0.01 in both dimensions, which would allow nearly diffraction limited focusing to be achieved.
Abstract
The AMBER-experiment 2, 1, located in the North Experimental Area at CERN, is the successor of the NA58/COMPASS 11 experiment which ran from 2002-2022. AMBER will start its data taking in ...2023. The experiment is served by the M2 beamline, employing secondary and tertiary beams produced by 400 GeV
c
-1
protons from the CERN Super Proton Synchrotron (SPS) impacting the T6 target. For the second phase of their measurements, AMBER will require high-intensity kaon beams 6, 7. This requirement for high-intensity beams implies a need for accurate particle identification allowing tagging particles of interest that would otherwise be lost for analysis. The beam particle identification is carried out using Cherenkov (CEDAR) detectors 5, whose tagging efficiency depends critically on the beam divergence. In this paper we investigate the beam parameters required, the performance achievable with the current layout of the beamline, as well as possible improvements.
A laserwire transverse electron beam size measurement system has been developed and operated at the Accelerator Test Facility 2 at the High Energy Accelerator Research Organization, Japan (KEK). ...Special electron beam optics were developed to create an approximately 1×100μm (vertical×horizontal ) electron beam at the laserwire location, which was profiled using 150 mJ, 71 ps laser pulses with a wavelength of 532 nm. The precise characterization of the laser propagation allows the non-Gaussian laserwire scan profiles caused by the laser divergence to be deconvolved. A minimum vertical electron beam size of 1.07±0.06(stat)±0.05(sys)μm was measured. A vertically focusing quadrupole just before the laserwire was varied while making laserwire measurements and the projected vertical emittance was measured to be 82.56±3.04pmrad .
Abstract
SHADOWS 1, 2 is an intended future beam dump experiment in the CERN North Area, aiming to search for feebly interacting particles (FIPs) 3 created in 400 GeV/c proton interactions. Due to ...its proposed off-axis location alongside the K12 beamline 4, the SHADOWS detector can be placed potentially very close to the beam dump, enabling it to search for FIPs in unexplored parts of the parameter space. In order to guarantee good quality of a potential signal, it is crucial to reduce any backgrounds of Standard Model particles as much as possible. The dominant background downstream the beam dump is caused by muons 1. This introduces the need of a dedicated muon sweeping system consisting of magnetised iron blocks (MIBs) to actively mitigate this background component. We present the conceptional design studies in the framework of the Conventional Beams Working Group of the Physics Beyond Colliders Initiative at CERN 5, 6.
Due to the advancement of proton therapy for cancer treatment, there has been a worldwide increase in the construction of treatment facilities. Therapy centres are often coupled with clinical, ...biological or material-science research programs. Research activities require proton beams at energies spanning an extensive range with higher beam currents and longer irradiation times than clinical conditions. Additionally, next-generation proton therapy systems are evolving towards more compact designs. In addition to the increased centres’ workloads, reducing the system in size produces a more significant number of secondary particles per unit volume and time. Therefore, the activation level of materials constituting those future proton therapy centres is expected to be higher, increasing the ambient dose and the amount of radioactive waste collected at the end of a centre’s lifetime. These operating conditions pose new challenges for the shielding design and the reduction of the concrete activation. To tackle them, we propose a novel approach to seamlessly simulate all the processes relevant for the evaluation of the concrete shielding activation using, as an illustration, the Ion Beam Applications Proteus
®
One system. A realistic model of the system is developed using Beam Delivery Simulation (BDSIM), a Geant4-based particle tracking code. It allows a single model to simulate primary and secondary particle tracking in the beamline, its surroundings, and all particle-matter interactions. The code system and library database FISPACT-II allows the computation of the shielding activation by solving the rate equations using ENDF-compliant group library data for nuclear reactions, particle-induced or spontaneous fission yields, and radioactive decay. As input, FISPACT-II is provided with the secondary particle fluences scored using the BDSIM Monte Carlo simulations. This approach is applied to the proton therapy research centre of Charleroi, Belgium. Results compare the evolution of the clearance level and the long-lived nuclide concentrations throughout the facility lifetime when using regular concrete or the newly developed Low Activation Concrete (LAC). A comparison with the initial shielding dimensioning has been performed for all the shielding walls to validate the methodology and highlight the clear benefits of integrating LAC inserts in the shielding design. The effectiveness of coupling BDSIM and FISPACT-II gives a glimpse of the possibility of a complete activation study following the actual workloads of the centre, allowing a better assessment of the shielding activation level at any time of the facility lifespan.
Due to the advancement of proton therapy for cancer treatment, there has been a worldwide increase in the construction of treatment facilities. Therapy centres are often coupled with clinical, ...biological or material-science research programs. Research activities require proton beams at energies spanning an extensive range with higher beam currents and longer irradiation times than clinical conditions. Additionally, next-generation proton therapy systems are evolving towards more compact designs. In addition to the increased centres’ workloads, reducing the system in size produces a more significant number of secondary particles per unit volume and time. Therefore, the activation level of materials constituting those future proton therapy centres is expected to be higher, increasing the ambient dose and the amount of radioactive waste collected at the end of a centre’s lifetime. These operating conditions pose new challenges for the shielding design and the reduction of the concrete activation. To tackle them, we propose a novel approach to seamlessly simulate all the processes relevant for the evaluation of the concrete shielding activation using, as an illustration, the Ion Beam Applications Proteus® One system. A realistic model of the system is developed using Beam Delivery Simulation (BDSIM), a Geant4-based particle tracking code. It allows a single model to simulate primary and secondary particle tracking in the beamline, its surroundings, and all particle-matter interactions. The code system and library database FISPACT-II allows the computation of the shielding activation by solving the rate equations using ENDF-compliant group library data for nuclear reactions, particle-induced or spontaneous fission yields, and radioactive decay. As input, FISPACT-II is provided with the secondary particle fluences scored using the BDSIM Monte Carlo simulations. This approach is applied to the proton therapy research centre of Charleroi, Belgium. Results compare the evolution of the clearance level and the long-lived nuclide concentrations throughout the facility lifetime when using regular concrete or the newly developed Low Activation Concrete (LAC). A comparison with the initial shielding dimensioning has been performed for all the shielding walls to validate the methodology and highlight the clear benefits of integrating LAC inserts in the shielding design. The effectiveness of coupling BDSIM and FISPACT-II gives a glimpse of the possibility of a complete activation study following the actual workloads of the centre, allowing a better assessment of the shielding activation level at any time of the facility lifespan.
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