Conceptual design report for the LUXE experiment Abramowicz, H.; Acosta, U.; Altarelli, M. ...
The European physical journal. ST, Special topics,
2021, Letnik:
230, Številka:
11
Journal Article
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This Conceptual Design Report describes LUXE (Laser Und XFEL Experiment), an experimental campaign that aims to combine the high-quality and high-energy electron beam of the European XFEL with a ...powerful laser to explore the uncharted terrain of quantum electrodynamics characterised by both high energy and high intensity. We will reach this hitherto inaccessible regime of quantum physics by analysing high-energy electron-photon and photon-photon interactions in the extreme environment provided by an intense laser focus. The physics background and its relevance are presented in the science case which in turn leads to, and justifies, the ensuing plan for all aspects of the experiment: Our choice of experimental parameters allows (i) field strengths to be probed where the coupling to charges becomes non-perturbative and (ii) a precision to be achieved that permits a detailed comparison of the measured data with calculations. In addition, the high photon flux predicted will enable a sensitive search for new physics beyond the Standard Model. The initial phase of the experiment will employ an existing 40 TW laser, whereas the second phase will utilise an upgraded laser power of 350 TW. All expectations regarding the performance of the experimental set-up as well as the expected physics results are based on detailed numerical simulations throughout.
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.
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.
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.
The Compact Linear Collider (CLIC) requires beam position monitors (BPMs) with 50 nm spatial resolution for alignment of the beam line elements in the main linac and beam delivery system. ...Furthermore, the BPMs must be able to make multiple independent measurements within a single 156 ns long bunch train. A prototype cavity BPM for CLIC has been manufactured and tested on the probe beam line at the 3rd CLIC Test Facility (CTF3) at CERN. The transverse beam position is determined from the electromagnetic resonant modes excited by the beam in the two cavities of the pickup, the position cavity and the reference cavity. The mode that is measured in each cavity resonates at 15 GHz and has a loaded quality factor that is below 200. Analytical expressions for the amplitude, phase and total energy of signals from long trains of bunches have been derived and the main conclusions are discussed. The results of the beam tests are presented. The variable gain of the receiver electronics has been characterized using beam excited signals and the form of the signals for different beam pulse lengths with the 2/3 ns bunch spacing has been observed. The sensitivity of the reference cavity signal to charge and the horizontal position signal to beam offset have been measured and are compared with theoretical predictions based on laboratory measurements of the BPM pickup and the form of the resonant cavity modes as determined by numerical simulation. Lastly, the BPM was calibrated so that the beam position jitter at the BPM location could be measured. It is expected that the beam jitter scales linearly with the beam size and so the results are compared to predicted values for the latter.
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 1×100 μm (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±3.04 pm rad.
Optical transition radiation (OTR) has become a commonly used method for 2D beam imaging measurements. In the Accelerator Test Facility 2 (ATF2) at KEK, beam sizes smaller than the OTR point spread ...function have been measured. Simulations of the OTR imaging system have been performed using the ZEMAX software to study the effects of optical errors such as aberrations, diffraction, and misalignments of optical components. This paper presents a comparison of simulations of the OTR point spread function with experimental data obtained at ATF2. It shows how the quantification and control of optical errors impacts on optimizing the resolution of the system. We also show that the OTR point spread function needs to be predicted accurately to optimize any optical system and to predict the error made on measurement.
CERN has a unique set of secondary beam lines, which deliver particles extracted from the PS and SPS accelerators after their interaction with a target material reaching energies up to 400 GeV. These ...beam lines provide a crucial contribution for test beam facilities, and host several fixed target experiments. A correct operation of the beam lines requires precise simulations of the beam optics and studies on the beam-matter interaction, radiation protection, beam equipment survival etc. BDSIM combines tracking studies with energy deposition and beam-matter interaction simulations within one software framework. This paper presents studies conducted on secondary beam lines with BDSIM for the beam lines T9 and T10. We report the tracking analysis and the energy deposition along the beam line. Tracking analysis validation is demonstrated via comparison to existing tracking codes.
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