Muons offer a unique opportunity to build a compact high-energy electroweak collider at the 10 TeV scale. A Muon Collider enables direct access to the underlying simplicity of the Standard Model and unparalleled reach beyond it. It will be a paradigm-shifting tool for particle physics representing the first collider to combine the high-energy reach of a proton collider and the high precision of an electron-positron collider, yielding a physics potential significantly greater than the sum of its individual parts. A high-energy muon collider is the natural next step in the exploration of fundamental physics after the HL-LHC and a natural complement to a future low-energy Higgs factory. Such a facility would significantly broaden the scope of particle colliders, engaging the many frontiers of the high energy community. The last European Strategy for Particle Physics Update and later the Particle Physics Project Prioritisation Panel in the US requested a study of the muon collider, which is being carried on by the International Muon Collider Collaboration. In this comprehensive document we present the physics case, the state of the work on accelerator design and technology, and propose an R&D project that can make the muon collider a reality.

Current Total Skin Electron Therapy (TSET) Stanford technique for cutaneous lymphoma, established in the 70's, involves a unique irradiation setup, i.e. patient's position and beam arrangement, for all patients with ensuing great variability in dose distribution and difficult dose optimization. A Geant4-based simulation has been developed to explore the possibility of personalizing the dose to each patient's anatomy. To achieve this optimization of the treatment method, this project enrolls different aspects of the clinical and computational techniques: starting with the knowledge of the experimental parameters involving TSET practice, passing through an innovative approach to model the patient's anatomy, a precise description of the electron beam and a validated configuration of the physics models handling the interactions of the electrons and of secondary particles. The Geant4-based simulation models the patient as a tessellated solid derived from the optical scan of her/his body, realistically reproduces the irradiation environment in detail and calculates the energy deposition corresponding to each facet of the patient's scanned surface. The resulting three-dimensional dose distribution constitutes the basis for the personalization of the medical treatement as appropriate to each patient's specific characteristics.

The radiological protection has the purpose of safeguarding the physical well-being of the user, preventing exposure to detrimental levels of ionizing radiation. This study introduces a novel, cost-effective category of lead-free elastomeric material designed for radiation shielding. The filler compounds utilized are notably lighter than conventional lead-based materials, enhancing user ergonomics during application. They comprise of a blend of barium sulfate combined or not with magnesium oxide with addition-cure liquid silicone rubber. To ensure the effectiveness of the radiation shielding, X-ray transmission measurements were performed for the different thicknesses of the materials and the results compared with Monte Carlo simulations. Additionally, the physical properties of the new materials, such as density, homogeneity, tensile strength, viscosity, and wettability, were also evaluated. The findings indicate that both materials fulfill the requirement for application in radiation protection garments.

Several sources of total cross sections for e+e− pair production by photon interaction with matter, used by major Monte Carlo codes for particle transport, are quantitatively evaluated with respect to experimental measurements collected from the literature. They include data libraries deriving from theoretical calculations and analytical formulae representing empirical fits to tabulations. Although most of these sources of cross sections are based on one theoretical reference, the statistical data analysis documented in this paper highlights differences in their compatibility with experiment. The cross sections collected in the 1997 version of the Evaluated Photon Data Library (EPDL) exhibit the lowest incompatibility with experiment; the paper details the validation results for all the examined cross section sources. The scarcity of experimental data does not allow the validation process to discern pair production in the field of the nucleus and in the field of atomic electrons; nevertheless, this paper documents relevant clues regarding the contribution of the latter to reproduce experimental measurements.

Accurate simulation of the energy deposited by electrons in matter is an essential requirement of Monte Carlo particle transport codes. It involves multiple components present in these codes: physics models and parameters, the transport schemes adopted to deal with electron interactions, and empirical algorithms and parameters. In this conference paper we report new results of recent validation tests, which exploit high precision experimental measurements and an extensive set of simulation test cases to identify the contribution of different Geant4 components to the accuracy of the simulation of this observable. The validation tests concerns the series of Geant4 version 10 releases and the Geant4 11.0 version.

To ensure the protection of individuals, different materials have been used as shielding from ionizing radiation, among them the barium sulfate (barite) stands out for presenting good attenuation of photon beams for distinct energies, including those used in radiotherapy. In this context, this work provides three compositions of barium concretes: T.REF (reference), T.10% SA (with 10% replacement of Portland cement with silica fume) and T.10% CV (with 10% replacement of Portland cement with fly ash) to investigate shielding effects against ionizing radiation generated by radiotherapy equipment. Concrete samples were characterized with respect to bulk density and axial compression strength. Regarding the effectiveness of the shielding, measurements of attenuation of the primary beam generated by a linear accelerator were carried out, for maximum acceleration voltages of 6 MV and 10 MV, as a function of the thickness of the samples. The density measurements show that the concretes were classified as "normal" as stated in NBR 8953. In the compressive strength tests, the concretes were in line with structural and severity criteria, according to NBR 6118. Concerning the shielding of ionizing radiation, the barium concrete T.10%CV showed the greater efficiency among all the proposed compositions, reducing the thickness of the wall of radiotherapy rooms by 80.91% with an attenuation of 95% of incident radiation. This trace is composed of fly ash, a residue from the burning of coal in thermoelectric plants. Therefore, in addition to proposing a reuse method and an adequate destination for solid waste, it was possible to reduce the consumption of clinker; the material responsible for most gaseous emissions in the cement manufacturing process. Furthermore, other barium concretes as T.REF and T.10%SA also proved to be suitable for application in protective barriers in radiotherapy rooms, although they presented lower attenuations than T.10%CV.

RESUMO Para garantir a proteção dos indivíduos, diversos materiais são utilizados para blindagem de radiação ionizante, dentre eles o sulfato de bário (barita), que se destaca por apresentar boa atenuação de feixes de fótons em diferentes energias, incluindo aqueles utilizados em radioterapia. Nesse contexto, este trabalho propõe três traços de concretos baritados: T.REF (referência), T.10%SA (com substituição de 10% de cimento Portland por sílica ativa) e T.10%CV (com substituição de 10% de cimento Portland por cinza volante) para investigar os efeitos da blindagem da radiação ionizante gerada por um equipamento de radioterapia. As amostras de concreto foram caracterizadas em relação as suas densidades aparentes e resistência à compressão axial. Para avaliar eficácia da blindagem, foram realizadas medidas de atenuação da radiação do feixe primário gerado por um acelerador linear, para tensões máximas de aceleração de 6 MV e 10 MV, em função da espessura dos corpos de prova. Quanto à densidade, todos os concretos baritados foram classificados como “normais” conforme a NBR 8953 e, em relação aos ensaios de resistência à compressão, todos atenderam aos critérios estruturais e de severidade do meio, segundo a NBR 6118. No tocante a blindagem da radiação ionizante, o concreto baritado T.10%CV apresentou maior eficiência reduzindo as espessas paredes das salas de radioterapia em 80,91% e atenuando 95% da radiação incidente. Este traço é composto por cinza volante, um resíduo proveniente da queima do carvão mineral em usinas termelétricas. Portanto, além de propor um método de reaproveitamento e uma destinação adequada ao resíduo sólido, foi possível reduzir o consumo de clínquer; material responsável pela maioria das emissões de gases poluentes no processo de fabricação de cimento. Ademais, os concretos baritados T.REF e T.10%SA também se mostraram adequados para serem aplicados em barreiras de proteções de salas de radioterapia, embora tenham apresentados atenuações menores que o T.10%CV.

Containers represent a well-known paradigm, which has been widely adopted in enterprises thanks to its ability to conveniently address issues related to fast delivery, portability and life-cycle management of software. On the contrary, they received so far modest attention in the scientific community and their adoption in experimental physics computing has progressed relatively slowly. Scientific applications are typically complex because of several factors. Among them the heterogeneous system requirements, i.e. specific versions of libraries and compilers, and the frequent updates, normally developed by researchers who are not familiar with software engineering principles. Containers would greatly foster scientific activities in terms of software availability, reproducibility, and shareability, in particular for small research groups that need to couple scientific, sysadmin and programming skills in one or a few persons. In this contribution we briefly present an experience using Singularity containers for running a multithreaded simulation based on Geant4 using different INFN computing infrastructures.

This chapter presents a specific reliability study of some GEANT4-DNA (version 10.02.p01) processes and models for proton transportation considering ultra-thin layers (UTL). The Monte Carlo radiation transport validation is fundamental to guarantee the simulation results accuracy. However, sometimes this is impossible due to the lack of experimental data and, it is then that the reliability evaluation takes an important role. Geant4-DNA runs in an energy range that makes impossible, nowadays, to perform a proper microscopic validation (cross-sections and dynamic diffusion parameters) and allows very limited macroscopic reliability. The chemical damage cross-sections reliability (experiment versus simulation) is a way to verify the consistency of the simulation results which is presented for 2 MeV incident protons beam on PMMA and PVC UTL. A comparison among different Geant4-DNA physics lists for incident protons beams from 2 to 20 MeV, interacting with homogeneous water UTL (2 to 200 nm) was performed. This comparison was evaluated for standard and five other optional physics lists considering radial and depth profiles of deposited energy as well as number of interactions and stopping power of the incident particle.

Exposure to ionizing radiation is increasingly common in the routine of modern society, due to the advances in health practices. Thus, attention should be drawn to the mechanisms of radiological protection in order to minimize the radiation absorbed by individuals, especially in healthcare facilities. A radiology room must have adequate shielding, considering materials with the appropriate density and thickness. In this context, this study proposes a concrete specific for the construction of radiology rooms, using barium sulfate (barite) and basalt rock in its composition. The concrete has an average apparent density of 2.46 g/cm(3), being classified as normal, according to its density, avoiding overload generated by its structure. During resistance to axial compression characteristic (fck) tests, the concrete reached the value of 102.90 MPa. This value represents an increase of 157% when compared to fck for a higher class of environmental aggressiveness (40 MPa), as provided in NBR 6118. For the radiation shielding tests, 5 prismatic samples with area 10 cm x 10 cm, and thicknesses varying from 2 mm to 10 mm, were molded. The shielding efficiency was measured by an ionization chamber, positioned below the samples, for different energy values of the X-ray beam (60, 90 and 125 kVp). The results indicate that even for 125 kVp, one of the highest values used in most radiology equipment, a thickness of 16.70 mm is sufficient to block 95% of X-radiation, as recommended by the Federal Ordinance No. 453 of Anvisa. This set of factors, in particular its shielding capacity, shows that the proposed concrete is suitable for applications in radiology room shielding.

As blindagens são uma parte fundamental na radioproteção. A construção de curvas de transmissão para um material utilizado como blindagem é importante para a definição da espessura necessária da blindagem. O principal objetivo deste trabalho é desenvolver um método para caracterizar novos materiais para blindagem de fótons usando a ferramenta computacional Geant4. As amostras irradiadas, denominadas Traço A, B e C, foram produzidas no Laboratório de Resistência de Materiais da UCPel. As validações experimentais de caracterização das amostras foram realizadas pelo teste da camada semirredutora (CSR), medida de kerma e medidas de Rutherford Backscattering Spectrometry (RBS), sendo os dois primeiros validados por meio de simulações. Os resultados de RBS e do imageamento mostraram a influência da granularidade dos agregados do concreto na homogeneidade e reprodutibilidade das amostras. A validação da aplicação foi feita por meio da verificação dos espectros teóricos e simulados, da geometria de radiação e caracterização do material. Os espectros teóricos e simulados foram validados por testes estatísticos, sendo considerados equivalentes. A geometria de radiação foi validada utilizando um visualizador e as ferramentas de verificação da geometria disponibilizadas pelo Geant4. Espera-se, com esses resultados, fazer medidas experimentais e criar curvas de transmissão simuladas para aplicações na radiologia diagnóstica e radioterapia.

RESUMO A exposição à radiação ionizante está mais presente na rotina da sociedade atual em consequência do avanço das práticas de saúde. Desta forma, deve-se atentar aos mecanismos de proteção radiológica de modo a minimizar a radiação absorvida pelos indivíduos, principalmente em unidades de saúde. Uma sala de radiologia deve contar com uma blindagem adequada, considerando materiais com densidade e espessura apropriados. Nesse contexto, este estudo propõe um concreto específico para construção de salas de radiologia, utilizando o sulfato de bário (barita) e a rocha de basalto em sua composição. O concreto possui uma densidade aparente média de 2,46 g/cm³, sendo classificado como normal, de acordo com sua densidade, evitando assim excessos de carregamento gerados pela sua estrutura. Nos testes de resistência à compressão axial característica (fck), o concreto atingiu o valor de 102,90 MPa, um aumento de 157% quando comparado ao fck para maior classe de agressividade ambiental (40 MPa), conforme estipulado pela NBR 6118. Para os ensaios de blindagem frente à radiação X, foram moldados 5 corpos de prova prismáticos de seção transversal 10 cm x 10 cm, com espessuras variando de 2 mm a 10 mm. A eficácia da blindagem foi aferida por uma câmara de ionização, posicionada abaixo dos corpos de prova, para diferentes valores de energia do feixe de raios X (60, 90 e 125 kVp). Os resultados indicam que mesmo para 125 kVp, um dos maiores valores utilizados na maioria dos equipamentos de radiologia, uma espessura de 16,70 mm é suficiente para barrar 95% da radiação X, conforme recomendado pela Portaria Federal n°453 da Anvisa. Esse conjunto de fatores, em especial a sua capacidade de blindagem, mostram que o concreto proposto é adequado para aplicações em blindagens de salas de radiologia.

Obtaining information on sediment deposition is a difficult task due to the fragility of the analyzed medium. The use of non-destructive tests to produce reliable data in these environments is being evaluated by some researchers. The current study proposes the computed tomography (CT) irradiation geometry evaluation, for obtaining images of the sediment deposition layers. As a first stage, planar images of geometric objects in centered geometry, similar to those resulting from the CT processes, were simulated using the dedicated X-Ray Monte Carlo (XRMC) code. Then, the x-rays were processed using the Feldkamp, David and Kress (FDK) reconstruction algorithm to generate the three-dimensional volume. Evaluating the FDK method for the reconstruction of the 8 to 64 color bits images, the obtained results were satisfactory for 64 bits grayscale images. The method showed accuracy in the contrast objects measurements, presenting a maximum deviation of 8%. This article discusses the constructed image artifacts and also, the advantages and disadvantages of the reconstruction method. The results show the feasibility of applying the methodology to produce detailed images of sediment samples collected in lakes, rivers or deposition simulation tanks.

Monte Carlo technique has been widely used as an important tool to develop new irradiation equipment, prototype medical equipment parts, and test methodologies for dosimetry. In this manuscript, we present a methodology to design a low power X-ray tube generator using the Geant4 Monte Carlo toolkit. The simulations were performed considering a large number of variables, namely, the material composition of the target track, the window thickness, and the air pressure of the X-ray tube. The X-ray production was simulated considering monoenergetic electron beams impinging on targets of tungsten and copper with incident kinetic energies ranging from 20 keV to 60 keV and initial divergences from 5° to 30°. For the polyenergetic emission, a conservative approach with Gaussian energy distribution was adopted. The analysis indicates that among the evaluated parameters, the incident kinetic energy, and the target material produced the most notable changes in the spectra shape and conversion efficiency (CE), significantly impacting the X-ray tube design. The studies provide a reliable methodology to explore general configurations for X-ray tube generators, defining the best geometry, material compositions, and thicknesses to be used on spectroscopy applications.

Imaging techniques using protons are currently being actively developed for proton therapy. Presently, many researchers use the GEANT4 toolkit to simulate proton imaging devices, without, however, detailed analysis of its precision for the case of thick absorbers. In this paper we present a systematic comparison of the quantities important for proton imaging as simulated by different physics lists of GEANT4 (version 9.6.p03) in the conditions close to those of proton medical imaging. We evaluated the physics lists FTF_BIC_EMY, FTFP_BERT_EMY, QGSP_BERT_95_EMY, QGSP_BERT_EMY, QGSP_BIC_EMV, and QGSP_BIC_EMY. The kinetic energies, angles, and coordinates of protons exiting the absorber were analysed. The significant differences in the physical observables were detected between EMY and EMV models of electromagnetic processes. The difference between BERT and BIC models of nuclear processes is at least 10 times smaller. The obtained results may be used not only in proton imaging but also as a test for nuclear models in future experiments with thick absorbers.

The use of Monte Carlo general toolkits to different applications, especially the ones that has multiple processes and models available to transport the same particle kind requires, more and more, associate to the application development the transport radiation knowledge and the validation or reliability evaluation, in order to define the best transport process and model evoked by the simulation. When the validation is impossible, due to the lack of experimental data, the reliability evaluation takes an important role. In addition, when multiple transport processes and models are available, it is important to perform a quantitative comparison among the possible options to apply a specifi c study case to guarantee the accuracy of simulation results. The Geant4-DNA is a Monte Carlo simulation toolkit that works in an energy range that makes it impossible, nowadays, to perform a proper microscopic validation of the cross-sections and the dynamic diffusion parameters but allows, very limited, macroscopic validation, especially because it may simulate physics, physical-chemistry and chemistry processes applied to molecular geometries for quantifi cation of damage (such as single-strand, double-strand breaks, base oxidation...). Considering the complexity of the physics, physical-chemistry and chemistry processes simulated it is important to guaranty the accuracy of the beginning of this dynamic process by getting the best model to simulate the radiation transport and energy deposition. This paper presents a reliability evaluation for incident protons beam of 2 MeV on polymers ultra-thin fi lms. Furthermore, comparison among different available physics lists Geant4-DNA (version 10.02.p01) with incident protons beam for different energies (2 to 20 MeV) interacting with homogeneous ultra-thin layers of water (2 to 200 nm) was performed. In general, the standard (DNA) physics list of Geant4-DNA presented the most consistent results and the DNA-Opt1 physics list was more time consuming, presenting the worst results for dosimetry for ultrathin layers.

Imaging techniques using protons as incident particles are currently being actively developed as a substitute for X-ray computed tomography and nuclear magnetic resonance methods in proton therapy. In proton imaging, density resolution depends on the position of the maximum of the exit energy distribution and the width of this distribution which influences uncertainty in the definition of the exit energy. In recent years, many research groups have used the GEANT4 toolkit to simulate proton imaging devices, without, however, detailed analysis of the reproducibility of the physical quantities simulated by the different models in GEANT4 for the case of thick absorbers. In the present report, we performed a careful quantitative comparison of the experimental and simulated parameters of the exit energy spectra that are important for proton imaging. The difference in exit energy between the BERT and BIC models does not exceed 0.5%, while between EMY and EMV models it is always much larger and reaches 2.5% and is accompanied by a significant difference in spectrum shape. The differences between exit energies and widths of the simulated and measured distributions do not exceed 15% and depend on the exit energy (absorber thickness).

The many applications of Monte Carlo modeling in nuclear medicine imaging make it desirable to increase the accuracy and computational speed of Monte Carlo codes. The accuracy of Monte Carlo simulations strongly depends on the accuracy in the probability functions and, thus, on the cross-section libraries used for photon-transport calculations. A comparison between different photon cross-section libraries and parameterizations implemented in Monte Carlo simulation packages developed for positron emission tomography and the most recent Evaluated Photon Data Library (EPDL97) developed by the Lawrence Livermore National Laboratory, Livermore, CA, was performed for several human tissues and common detector materials for energies from 1 keV to 1 MeV. Different photon cross-section libraries and parameterizations show quite large variations when compared to the EPDL97 coefficients. This latter library is the more up-to-date complete and consistent library available, and was carefully designed in the form of look-up tables providing efficient data storage, access, and management. EPDL97 is already a standard in the nuclear reactor industry. Its use as a standard in the simulation of medical imaging systems will help to eliminate potential differences between the results obtained with different codes. Together with the optimization of the computing time performances of the Monte Carlo software package, Eidolon, photon transport in three-dimensional (3-D) positron emission tomography could be efficiently modeled to develop accurate scatter models and better understand scatter correction techniques.

In this chapter, the Monte Carlo (MC) core is presented, particularly its cross-sectional libraries and random generators. The main idea is to introduce validation and reliability of MC applications and to explore its limitations. As an example, a comparison between two MC toolkits, namely XRMC (version 6.5.0–2) and Geant4 (version 10.02.p02), and a validation between each of them and experimental data applied to mammography (external dosimetry) are presented. The simulated quantities compared are exposure, kerma, half-value layer, and backscattering. Limitations, advantages, and disadvantages of using a general and specific MC toolkit are commented too.