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Maria Grazia Pia

Publications and source records attributed to Maria Grazia Pia.

At least 19 recordsLinked to original sources
arXiv2024

Geant4: a Game Changer in High Energy Physics and Related Applicative Fields

Geant4 is an object-oriented toolkit for the simulation of the passage of particles through matter. Its development was initially motivated by the requirements of physics experiments at high energy hadron colliders under construction in the last decade of the 20th century. Since its release in 1998, it has been exploited in many different applicative fields, including space science, nuclear physics, medical physics and archaeology. Its valuable support to scientific discovery is demonstrated by more than 16000 citations received in the past 25 years, including notable citations for main discoveries in different fields. This accomplishment shows that well designed software plays a key role in enabling scientific advancement. In this paper we discuss the key principles and the innovative decisions at the basis of Geant4, which made it a game changer in high energy physics and related fields, and outline some considerations regarding future directions.

physics.comp-ph↗
arXiv2023

Geant4 Silver Anniversary: 25 years enabling scientific production

This paper summarizes Geant4 contribution to scientific research over the past 25 years through a scientometric analysis of the results with which it has been associated. The scientometric data collected from scholarly literature and databases are evaluated with methods pertaining to econometrics and ecology to quantify relevant traits, diversity and disparity in their scientific and geographic distributions, and to identify statistically significant trends. The analysis reviews the contribution of Geant4 to the field - experimental particle physics - that originally motivated its development and highlights its role in other research domains including nuclear physics and engineering, astrophysics and space science, biomedical physics, archaeology and the cultural heritage.

physics.comp-ph↗
arXiv2023

Total Skin Electron Therapy Stanford Technique Evolution With Monte Carlo Simulation Toward Personalized Treatments For Cutaneous Lymphoma

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.

physics.comp-ph↗
arXiv2022

Validation of e$^+$e$^-$ Pair Production Total Cross Sections for Monte Carlo Particle Transport

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 the 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, the paper documents relevant clues regarding the contribution of the latter to reproduce experimental measurements.

physics.comp-ph↗
arXiv2020

Evolutions in photoelectric cross section calculations and their validation

This paper updates and complements a previously published evaluation of computational methods for total and partial cross sections, relevant to modeling the photoelectric effect in Monte Carlo particle transport. It examines calculation methods that have become available since the publication of the previous paper, some of which claim improvements over previous calculations; it tests them with statistical methods against the same sample of experimental data collected for the previous evaluation. No statistically significant improvements are observed with respect to the calculation method identified in the previous paper as the state of the art for the intended purpose, encoded in the EPDL97 data library. Some of the more recent computational methods exhibit significantly lower capability to reproduce experimental measurements than the existing alternatives.

physics.comp-ph↗
arXiv2020

Electromagnetic Data Libraries: recent evolutions and new perspectives

This paper summarizes the current status of the electromagnetic data libraries, reviews recent experimental validation results, highlights open issues and introduces new perspectives for the future of these data libraries taking shape in the context of INFN research. Special emphasis is given to the characteristics of reliability, transparency and openness, along with opportunities for the improvement and the extension of the physics content.

physics.comp-ph↗
arXiv2017

Application of Econometric Data Analysis Methods to Physics Software

We report an investigation of data analysis methods derived from other disciplines, which we applied to physics software systems. They concern the analysis of inequality, trend analysis and the analysis of diversity. The analysis of inequality exploits statistical methods originating from econometrics; trend analysis is typical of economics and environmental sciences; the analysis of diversity is based on concepts derived from ecology and treats software as an ecosystem. To the best of our knowledge, this is an innovative exploration, as we could not find track of previous use of these methods in the experimental physics domains within the scope of the IEEE Nuclear Science Symposium. We applied these methods in the context of Geant4 physics validation and Geant4 maintainability assessment.

cs.SE↗
arXiv2016

Quantitative Test of the Evolution of Geant4 Electron Backscattering Simulation

Evolutions of Geant4 code have affected the simulation of electron backscattering with respect to previously published results. Their effects are quantified by analyzing the compatibility of the simulated electron backscattering fraction with a large collection of experimental data for a wide set of physics configuration options available in Geant4. Special emphasis is placed on two electron scattering implementations first released in Geant4 version 10.2: the Goudsmit-Saunderson multiple scattering model and a single Coulomb scattering model based on Mott cross section calculation. The new Goudsmit-Saunderson multiple scattering model appears to perform equally or less accurately than the model implemented in previous Geant4 versions, depending on the electron energy. The new Coulomb scattering model was flawed from a physics point of view, but computationally fast in Geant4 version 10.2; the physics correction released in Geant4 version 10.2p01 severely degrades its computational performance. Evolutions in the Geant4 geometry domain have addressed physics problems observed in electron backscattering simulation in previous publications.

physics.comp-ph↗
arXiv2016

Software Quality Metrics for Geant4: An Initial Assessment

In the context of critical applications, such as shielding and radiation protection, ensuring the quality of simulation software they depend on is of utmost importance. The assessment of simulation software quality is important not only to determine its adoption in experimental applications, but also to guarantee reproducibility of outcome over time. In this study, we present initial results from an ongoing analysis of Geant4 code based on established software metrics. The analysis evaluates the current status of the code to quantify its characteristics with respect to documented quality standards; further assessments concern evolutions over a series of release distributions. We describe the selected metrics that quantify software attributes ranging from code complexity to maintainability, and highlight what metrics are most effective at evaluating radiation transport software quality. The quantitative assessment of the software is initially focused on a set of Geant4 packages, which play a key role in a wide range of experimental applications and are representative of different software development processes. We provide an interpretation of the data resulting from measurements on the selected Geant4 packages, and discuss methods to improve them. This work can be used as a baseline for evaluating correlations between software quality embedded in the Geant4 development process and simulation observables produced by Geant4-based applications. The result provide constructive guidance both to improve key software tools, such as Geant4, and to estimate their contribution in risk analyses concerning sensitive applications.

cs.SE↗
arXiv2016

Validation of cross sections for Monte Carlo simulation of the photoelectric effect

Several total and partial photoionization cross section calculations, based on both theoretical and empirical approaches, are quantitatively evaluated with statistical analyses using a large collection of experimental data retrieved from the literature to identify the state of the art for modeling the photoelectric effect in Monte Carlo particle transport. Some of the examined cross section models are available in general purpose Monte Carlo systems, while others have been implemented and subjected to validation tests for the first time to estimate whether they could improve the accuracy of particle transport codes. The validation process identifies Scofield's 1973 non-relativistic calculations, tabulated in the Evaluated Photon Data Library(EPDL), as the one best reproducing experimental measurements of total cross sections. Specialized total cross section models, some of which derive from more recent calculations, do not provide significant improvements. Scofield's non-relativistic calculations are not surpassed regarding the compatibility with experiment of K and L shell photoionization cross sections either, although in a few test cases Ebel's parameterization produces more accurate results close to absorption edges. Modifications to Biggs and Lighthill's parameterization implemented in Geant4 significantly reduce the accuracy of total cross sections at low energies with respect to its original formulation. The scarcity of suitable experimental data hinders a similar extensive analysis for the simulation of the photoelectron angular distribution, which is limited to a qualitative appraisal.

physics.comp-ph↗
arXiv2015

Investigation of Geant4 Simulation of Electron Backscattering

A test of Geant4 simulation of electron backscattering recently published in this journal prompted further investigation into the causes of the observed behaviour. An interplay between features of geometry and physics algorithms implemented in Geant4 is found to significantly affect the accuracy of backscattering simulation in some physics configurations.

physics.comp-ph↗
arXiv2015

How do particle physicists learn the programming concepts they need?

The ability to read, use and develop code efficiently and successfully is a key ingredient in modern particle physics. We report the experience of a training program, identified as "Advanced Programming Concepts", that introduces software concepts, methods and techniques to work effectively on a daily basis in a HEP experiment or other programming intensive fields. This paper illustrates the principles, motivations and methods that shape the "Advanced Computing Concepts" training program, the knowledge base that it conveys, an analysis of the feedback received so far, and the integration of these concepts in the software development process of the experiments as well as its applicability to a wider audience.

physics.ed-ph↗
arXiv2015

Validation Test of Geant4 Simulation of Electron Backscattering

Backscattering is a sensitive probe of the accuracy of electron scattering algorithms implemented in Monte Carlo codes. The capability of the Geant4 toolkit to describe realistically the fraction of electrons backscattered from a target volume is extensively and quantitatively evaluated in comparison with experimental data retrieved from the literature. The validation test covers the energy range between approximately 100 eV and 20 MeV, and concerns a wide set of target elements. Multiple and single electron scattering models implemented in Geant4, as well as preassembled selections of physics models distributed within Geant4, are analyzed with statistical methods. The evaluations concern Geant4 versions from 9.1 to 10.1. Significant evolutions are observed over the range of Geant4 versions, not always in the direction of better compatibility with experiment. Goodness-of-fit tests complemented by categorical analysis tests identify a configuration based on Geant4 Urban multiple scattering model in Geant4 version 9.1 and a configuration based on single Coulomb scattering in Geant4 10.0 as the physics options best reproducing experimental data above a few tens of keV. At lower energies only single scattering demonstrates some capability to reproduce data down to a few keV. Recommended preassembled physics configurations appear incapable of describing electron backscattering compatible with experiment. With the support of statistical methods, a correlation is established between the validation of Geant4-based simulation of backscattering and of energy deposition.

physics.comp-ph↗
arXiv2014

Geant4 and beyond: recent progress in precision physics modeling

This extended abstract briefly summarizes ongoing research activity on the evaluation and experimental validation of physics methods for photon and electron transport. The analysis includes physics models currently implemented in Geant4 as well as modeling methods used in other Monte Carlo codes, or not yet considered in general purpose Monte Carlo simulation systems. The validation of simulation models is performed with the support of rigorous statistical methods, which involve goodness-of-fit tests followed by categorical analysis. All results are quantitative, and are fully documented.

physics.comp-ph↗
arXiv2014

Scholarly literature and the press: scientific impact and social perception of physics computing

The broad coverage of the search for the Higgs boson in the mainstream media is a relative novelty for high energy physics (HEP) research, whose achievements have traditionally been limited to scholarly literature. This paper illustrates the results of a scientometric analysis of HEP computing in scientific literature, institutional media and the press, and a comparative overview of similar metrics concerning representative particle physics measurements. The picture emerging from these scientometric data documents the scientific impact and social perception of HEP computing. The results of this analysis suggest that improved communication of the scientific and social role of HEP computing would be beneficial to the high energy physics community.

physics.soc-ph↗
arXiv2014

Theoretical grounds for the propagation of uncertainties in Monte Carlo particle transport

We introduce a theoretical framework for the calculation of uncertainties affecting observables produced by Monte Carlo particle transport, which derive from uncertainties in physical parameters input into simulation. The theoretical developments are complemented by a heuristic application, which illustrates the method of calculation in a streamlined simulation environment.

physics.data-an↗
arXiv2014

Validation of Compton Scattering Monte Carlo Simulation Models

Several models for the Monte Carlo simulation of Compton scattering on electrons are quantitatively evaluated with respect to a large collection of experimental data retrieved from the literature. Some of these models are currently implemented in general purpose Monte Carlo systems; some have been implemented and evaluated for possible use in Monte Carlo particle transport for the first time in this study. Here we present first and preliminary results concerning total and differential Compton scattering cross sections.

physics.comp-ph↗