Giovanni Santin

• PhD
• European Space Agency

The RADiation–hard Electron Monitor (RADEM) is an instrument on board the ESA JUpiter ICy moons Explorer (JUICE) deep-space mission launched on April 14th, 2023. As a part of the Cosmic Vision program, RADEM on JUICE will spend over three years exploring the radiation environment of the Jovian system, including its icy moons Ganymede, Callisto, and...

Galactic cosmic rays (GCR) are among the biggest hindrances to crewed space exploration. The ions contributing the most to fluence and absorbed dose in free space are 1H and 4He. In addition, their contribution to dose equivalent increases behind thick shields. In this work, the results of depth-dose measurements performed with high-energy 1H and 4...

Radiation quality for determining biological effects is commonly linked to the microdosimetric quantity lineal energy (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$y...

The discrete physics models available in the Geant4-DNA Monte Carlo toolkit are a subject of continuous evolution and improvement in order to meet the needs of state-of-the-art radiobiological research for medical and space applications. The current capabilities of Geant4-DNA for event-by-event electron transport extend up to 1 MeV. In this work, G...

We present a simulation-assisted methodology for the design of point or distributed fiber dosimeters exploiting the linear dependence of the infrared radiation-induced attenuation of a single-mode phosphosilicate optical fiber. We demonstrate by comparing Monte Carlo simulations and experiments at different irradiation facilities (X-rays, γ-rays, p...

Standard Heavy-Ion Single Event Rate estimation methods are well adapted to mature technologies used in the space industry. However, the adoption of 3D structures as well as advanced technology nodes may reduce the confidence in established rate estimation methods such as IRPP. In this work, an SEE rate calculation method with a GEANT4 based Monte-...

A chemistry module has been implemented in Geant4‐DNA since Geant4 version 10.1 to simulate the radiolysis of water after irradiation. It has been used in a number of applications, including the calculation of G‐values and early DNA damage, allowing the comparison with experimental data. Since the first version, numerous modifications have been mad...

In order to have an independent, repeatable, consistent, and flexible method to assess and compare heavy ion beams produced by different heavy ion irradiation facilities, a system has been developed in ESA laboratories to acquire and analyze the energy spectra of heavy ion beams. This system based on silicon detector is composed of a degrader syste...

Space radiation exposure from omnipresent Galactic Cosmic Rays (GCRs) in interplanetary space poses a serious carcinogenic risk to astronauts due to the—limited or absent—protective effect of the Earth’s magnetosphere and, in particular, the terrestrial atmosphere. The radiation risk is directly influenced by the quality of the radiation, i.e., its...

Human spaceflight is entering a new era of sustainable human space exploration. By 2030 humans will regularly fly to the Moon’s orbit, return to the Moon’s surface and preparations for crewed Mars missions will intensify. In planning these undertakings, several challenges will need to be addressed in order to ensure the safety of astronauts during...

Purpose Track structure Monte Carlo (MC) codes have achieved successful outcomes in the quantitative investigation of radiation-induced initial DNA damage. The aim of the present study is to extend a Geant4-DNA radiobiological application by incorporating a feature allowing for the prediction of DNA rejoining kinetics and corresponding cell survivi...

Galactic cosmic rays (GCR) are among the main deterrents to manned space exploration. Currently, the most realistic way to reduce the dangers caused by GCR to acceptable levels is passive shielding. Light materials guarantee the strongest dose attenuation per unit mass. High-density polyethylene is considered the gold standard for radiation protect...

The last generation of X-ray focusing telescopes operating outside the Earth's radiation belt discovered that optics were able to focus not only astrophysical X-ray photons, but also low-energy heliophysical protons entering the Field of View (FOV). This "soft proton" contamination affects around 40\% of the observation time of XMM-Newton. The ATHE...

We studied the secondary byproducts created by high-energy protons inside a single-event upset (SEU) detector based on 3-D NAND Flash memories, extending the previously developed methodology used for detecting heavy ions. The radiation response of the SEU monitor was discussed as a function of proton energy, analyzing parameters such as the number...

The deposition of energy in large and small sensitive volumes is studied after ultra-high energy heavy-ion irradiation. We demonstrate that the energy deposition increase effect previously reported in PIN diode detectors due to delta electrons occurs only in large sensitive volumes, but not in small ones, typical of advanced microelectronic devices...

Realistic nuclear reaction cross-section models are an essential ingredient of reliable heavy-ion transport codes. Such codes are used for risk evaluation of manned space exploration missions as well as for ion-beam therapy dose calculations and treatment planning. Therefore, in this study, a collection of total nuclear reaction cross-section data...

Realistic nuclear reaction cross-section models are an essential ingredient to reliable heavy-ion transport codes. Such codes are used for risk evaluation of manned space exploration missions as well as for ion-beam therapy dose calculation and treatment planning. Therefore, a total nuclear reaction cross-section data collection has been generated...

A heavy-ion beam monitor based on 3-D NAND flash memories was designed and tested with heavy ions at high energy and low linear energy transfer (LET). The capability of measuring fluence, angle, uniformity, and LET of impinging particles is discussed, together with the advantages over SRAM-based implementations. We propose ad hoc algorithms for t...

The helium ( 4 He) component of the primary particles in the galactic cosmic ray spectrum makes significant contributions to the total astronaut radiation exposure. 4 He ions are also desirable for direct applications in ion therapy. They contribute smaller projectile fragmentation than carbon ( 12 C) ions and smaller lateral beam spreading than pr...

The energy deposited by heavy-ion beams was measured using a Passivated Implanted Planar Silicon (PIPS) detector in different facilities. Ion beams at ultra-high energy lead to the formation of a second, unexpected peak in the deposited energy spectrum at slightly higher energy, in addition to the expected primary peak. Monte Carlo simulations are...

The feasibility of a 3D NAND Flash based heavy-ion detector is explored. The possibility of measuring the angle of incidence and the LET of impinging particles, by studying the pattern of threshold voltage shifts along the track of affected cells is discussed. The results of experiments with different beams (both directly and indirectly ionizing) a...

An internal charging (IC) analysis of the active measurement box of electrostatic risk (AMBER) instrument onboard Jason-3 in polar earth orbit (PEO) has been performed with a new dedicated modeling chain. The ExtendeD Gdml Editor (EDGE) application is in charge of the definition of the computer-aided design (CAD) model. The Modelling Of Radiation (...

The advancement of multidisciplinary research fields dealing with ionising radiation induced biological damage – radiobiology, radiation physics, radiation protection and, in particular, medical physics – requires a clear mechanistic understanding of how cellular damage is induced by ionising radiation. Monte Carlo (MC) simulations provide a promis...

The European Space Agency (ESA) is currently expanding its efforts in identifying requirements and promoting research towards optimizing radiation protection of astronauts. Space agencies use common limits for tissue (deterministic) effects on the International Space Station. However, the agencies have in place different career radiation exposure l...

In this paper, possible mechanisms by which electrons can induce single-event latchups in electronics are discussed. The energy deposition and the nuclear fragments created by electrons in silicon are analyzed in this context. The cross section enhancement effect in the presence of high-Z materials is discussed. First experimental results of electr...

The roadmap for space exploration foresees longer journeys and further excursions outside low-Earth orbit as well as the establishment of permanent outposts on other celestial bodies, such as the Moon or Mars. The design of spacecraft and habitats depends heavily on the mission scenario and must consider the radiation protection properties of the s...

The experience gained with the current generation of X-ray telescopes like Chandra and XMM-Newton has shown that low energy “soft” protons can pose a severe threat to the possibility to exploit scientific data, reducing the available exposure times by up to 50% and introducing a poorly reproducible background component. These soft protons are prese...

In this paper we perform an in-depth analysis of the single-event effects observed during testing at medical electron linacs and an experimental high-energy electron linac. For electron irradiations the medical linacs are most commonly used due to their availability and flexibility. Whereas previous efforts were made to characterize the cross-secti...

The effects of heavy-ion irradiation on 3D NAND Flash memory cells are investigated. Threshold voltage distributions are studied before and after exposure, as a function of the linear energy transfer, fluence, and irradiation angle. Shifts are smaller in 3D devices than in planar ones, for the same equivalent bit density. The cell circular shape an...

A new model of dielectric conductivities has been implemented in SPIS-IC. It allows modeling the time-dependent behavior of the charge transport and the electric potential inside payload components under realistic radiation environments in space. The simulation results have been compared to experiments on four validation cases going from simple 1-D...

We present experimental evidence of electron induced upsets in a reference ESA SEU monitor, induced by a 200 MeV electron beam at the VESPER facility at CERN. Comparison of experimental cross-sections and simulated cross-sections are shown and the differences are analyzed. Possible secondary contributions to the upset rate by neutrons, flash effect...

Novel materials or multilayers can help to reduce the mass requirement for radiation shielding of electronic components significantly. In this study, potential alternatives to the standard aluminum shielding approach are assessed by Monte Carlo simulations and promising candidates are manufactured and characterized by radiation tests including prot...

The second L-class (large) mission in European Space Agency's Cosmic Vision program will be an X-ray telescope named Athena, planned to operate at the L2 Lagrange point of the Sun-Earth system. Current large X-ray space telescopes like XMM-Newton and Chandra have encountered periods of unexpectedly high background due to protons in the energy range...

We apply a Monte Carlo based integral rectangular parallelpiped (IRRP) approach to evaluate the impact of heavy ion reaction products on the Galactic Cosmic Ray (GCR) Single Event Effect (SEE) rate, concluding that owing to their similar high-energy (> 100 MeV/n) SEE cross section and much larger abundance, protons are expected to be the dominating...

Geant4 is a software toolkit for the simulation of the passage of particles through matter. It is used by a large number of experiments and projects in a variety of application domains, including high energy physics, astrophysics and space science, medical physics and radiation protection. Over the past several years, major changes have been made t...

This study focuses on the ion species and energy dependence of the heavy ion SEE cross section in the sub-LET threshold region through a set of experimental data. In addition, a Monte Carlo based model is introduced and applied, showing a good agreement with the data in the several hundred MeV/n range while evidencing large discrepancies with the m...

An accurate modeling of radial energy deposition around ion tracks is a key requirement of radiation transport software used for simulations in radiobiology at the sub-cellular scale. The work presented in this paper is part of the on-going benchmarking of the "Geant4-DNA" physics processes and models, which are available in the Geant4 Monte Carlo...

The most recent upgrades of the electromagnetic (EM) physics “standard” and “low energy” sub-libraries of the general purpose Geant4 Monte Carlo simulation toolkit are described. These upgrades are relevant to different application domains including high energy physics, medical physics and space science. Validation results are presented and discuss...

The solar energetic particle (SEP) radiation environment is an important consideration for spacecraft design, spacecraft mission planning and human spaceflight. Herein is presented an investigation into the likely severity of effects of a very large Solar Particle Event (SPE) on technology and humans in space. Fluences for SPEs derived using statis...

Radiation shielding is of primary importance in the planning of new interplanetary manned missions, and the ISS represents the largest laboratory for radiation shielding in space ever built. The ISS radiation environment has been thoroughly characterised by the Monte Carlo-based high-energy physics toolkit Geant4. It has been found that the ISS str...

The impact of high energy electrons in multi-layered shielding structures has been measured in terms of dose enhancement effects. New dosimetric data from a series of extensive experimental tests have been obtained and compared to the latest electromagnetic physics models included in the Geant4 Monte Carlo toolkit.

Several models of the high energy electron radiation environment in the Jovian system have been constructed, based on a limited set of data, principally from Voyager 1 and 2 and Galileo. The design of future missions to this harsh radiation environment requires characterisation of the environment and its uncertainties. From the uncertainties a marg...

This anthology contains contributions from eleven different groups, each developing and/or applying Monte Carlo-based radiation transport tools to simulate a variety of effects that result from energy transferred to a semiconductor material by a single particle event. The topics span from basic mechanisms for single-particle induced failures to app...

An overview of the current status of electromagnetic physics (EM) of the Geant4 toolkit is presented. Recent improvements are focused on the performance of large scale production for LHC and on the precision of simulation results over a wide energy range. Significant efforts have been made to improve the accuracy without compromising of CPU speed f...

The effects of heavy-ion test conditions and beam energy on device response are investigated. These effects are illustrated with two types of test vehicles; SRAMs and power MOSFETs. In addition, GEANT4 simulations have also been performed to better understand the results.

Through the use of experimental data and Monte Carlo simulations we investigate the shielding properties of spacecraft-shell compositions exposed to 1 GeV/nucleon ${}^{56}$ Fe ions, representative of the worst part of the Galactic Cosmic Ray (GCR) spectrum. Through the use of the Geant4 Radiation Analysis for Space (GRAS) tool, the dose reduction a...

An overview of the electromagnetic (EM) physics of the Geant4 toolkit is presented. Two sets of EM models are available: the "Standard" initially focused on high energy physics (HEP) while the "Low-energy" was developed for medical, space and other applications. The "Standard" models provide a faster computation but are less accurate for keV energi...

Through the use of the Geant4 Radiation Analysis for Space (GRAS) Monte Carlo tool, we present new results on the impact of shielding composition on spacecraft electronics Soft Error Rate (SER) induced by Galactic Cosmic Rays (GCR). The comparison with the aluminum-equivalent approach is performed using both G4/GRAS and CREME96 tool on a heterogene...

A review of Geant4 model and benchmark developments in the framework of an Electron Shielding project sponsored by ESA is presented. It includes extensions of electron ionisation models to lower energies, development of a new standard model of bremsstrahlung and a new angular generator of bremsstrahlung, and new standard models of Compton and Rayle...

The shape of the single event effect (SEE) cross section as a function of the ion's linear energy transfer (LET) can be explained in terms of intra-cell variations of the charge collection efficiency within the cell as opposed the inter-cell spread in the critical charge, as assumed earlier. Free charge carriers generated in areas in absence of ele...

A method is proposed that uses the fundamental physical differences between direct and indirect energy deposition processes to obtain accurate values of the sensitive volume (SV) thickness and critical charge of electronic devices. The intention is to calibrate a unified model capable of describing both heavy ion and proton test data through Monte...

On behalf of the Geant4 Standard and Low-Energy Electromagnetic Physics Working Groups. The authors are members of the Geant4-DNA collaboration. ABSTRACT Simulation of biological effects of ionizing radiation at the DNA scale requires not only the modeling of direct damages induced on DNA by the incident radiation and by secondary particles but als...

Charge collection is used as a non-destructive technique to analyze the statistical response of vertical power MOSFETs and their single-event burnout (SEB) rate as a function of the incident ion energy. Two effects are observed at either low or high energy. At low energy, the collected charge significantly decreases because of the limited ion range...

A comparative study was executed of the performance of commonly used radiation transport tools in the predictive capability of the impact of the harsh electron-dominated radiation environment on spacecraft and payloads of the joint international Europa Jupiter System Mission. The effectiveness of multi-layered, graded shielding structures was analy...

The Standard Radiation Environment Monitor (SREM) is a particle detector developed for wide use on ESA spacecraft. It is flying on several ESA missions, most recently the Herschel and Planck space telescopes. Using data from the SREM unit on PROBA-1 in LEO, pitch angle anisotropics in the inner Van Allen belt are investigated. The sensitivity of th...

We have implemented the reverse/adjoint Monte Carlo method into Geant4. In this method the primary particles are tracked backward from the sensitive part of the geometry till the external source surface by following the reverse processes. By this way the computing time is spent only for tracks that are contributing to the tallies and the reverse Mo...

In recent years applications such as mp3 players, SSD, digital cameras and video camcorders have driven the development of increasingly higher density NAND memories. In the presented 3b/cell memory the read and programming throughputs are been enhanced with the adoption of a quad-plane architecture and an industry standard even-odd bitline (BL) dec...

Assessment of risk from potential radiation-induced effects to space systems requires knowledge of both the conditions of the radiation environment and of the impact of radiation on sensi-tive spacecraft elements. During sensitivity analyses, test data are complemented by models to predict how external radiation fields are transported and modified...

A study was performed of the impact on the IXO focal plane detectors of electrons and low energy protons penetrating through the X-ray optics by a combination of reflection and scattering processes. Total (non-ionizing) dose and flux levels were obtained as a support to a detailed design of the mission configuration.

This paper describes some of the radiation environments and their effects encountered by the Cosmic Vision missions, with emphasis on the design specifications and verification tools, including new shielding analysis techniques. ore and more of ESA's space science missions leave the immediate environment of the Earth. ESA has a very ambitious space...

Simulations with a Monte Carlo tool kit have been performed to determine the radiation environment a specific device, called a biochip, would face if it were placed into a rover bound to explore Mars' surface. A biochip is a miniaturized device that can be used to detect organic molecules in situ. Its specific detection part is constituted of prote...

The high energy ionising radiation envi-ronment in the solar system consists of three main sources: the radiation belts, galactic cosmic rays and solar energetic particles. Future Mars missions potentially carry significant risk from long-term exposure to ionising radiation. The Martian Ener-getic Radiation Environment Models, MEREM, were developed...

The Giove-A spacecraft carries two radiation monitors, CEDEX, built by the University of Surrey and Merlin, built by QinetiQ, to study the radiation environment encountered in the Galileo orbit. The two monitors have been functioning since the beginning of the mission and have measured protons, heavy ions and electrons. The electron environment has...

Deposited dose values calculated, from two ray tracing methods are compared to 3D Monte Carlo Adjoint (reverse) results, for both simple and complex geometries. Results are analyzed, ray tracing accuracy discussed, and hardness assurance modification proposed.

Detecting life in the Solar System is one of the great challenges of new upcoming space missions. It implies to send new sophisticated devices to bodies of interest (like Mars) to try to perform in situ measurements which will give hints of the presence, or lack, of organic matter. One of those devices could be a miniaturized biological sensitive s...

The results of the measurements of the double-differential production cross-sections of pions, , in p–C and π±–C interactions using the forward spectrometer of the HARP experiment are presented. The incident particles are 12 GeV/c protons and charged pions directed onto a carbon target with a thickness of 5% of a nuclear interaction length. For p–C...

The results of the measurements of the double-differential production cross-sections of pions in p-C and $\pi^\pm$-C interactions using the forward spectrometer of the HARP experiment are presented. The incident particles are 12 GeV/c protons and charged pions directed onto a carbon target with a thickness of 5% of a nuclear interaction length. For...

Search for extraterrestrial life: new challenge Λ Mars: special exobiologic interest for upcoming missions (ESA-EXOMARS, NASA-PHOENIX...) Λ New tools, miniaturized, sensitive biochip development Λ Resistance of these new tools to space conditions? Λ Radiation : critical issue Λ Need for simulations to define relevant experiment parameters Λ BiOMAS...

A characterization of the Galactic cosmic ray (GCR) induced radiation environment on-board Columbus and the International Space Station (ISS) has been carried out using the Geant4 Monte Carlo particle transport toolkit and detailed geometry models of Columbus and ISS. Dose and dose equivalent rates, as well as penetrating particle spectra are prese...

A measurement of the double-differential π± production cross-section in proton–carbon, proton–copper and proton–tin collisions in the range of pion momentum 100MeV/c≤p<800MeV/c and angle 0.35rad≤θ<2.15rad is presented. The data were taken with the HARP detector in the T9 beam line of the CERN PS. The pions were produced by proton beams in a momentu...

Reliable models of the space radiation environment need precise and up-to-date measurements of the radiation fields in space. The analysis of the potential impact of modelled radiation on evolving space borne devices relies on precise tools for the understanding and the prediction of the basic effects of the particle environment on new technologies...

We present the status of the Geant4 Application for Emission Tomography (GATE) project, a Monte Carlo simulator for Single Photon Emission Computed Tomography (SPECT) and Positron annihilation Emission Tomography (PET). Its main features are reminded, including modelling of time dependent phenomena and versatile, user-friendly scripting interface....

The influence of geometry model approximations on Geant4 Monte Carlo simulation results of the radiation environment on-board the Columbus module of the International Space Station (ISS) has been investigated. Three geometry models of Columbus with different levels of detail and a geometry model of ISS have been developed. These geometries have bee...

A detailed characterization of the trapped-proton-induced radiation environment on board Columbus and the International Space Station (ISS) has been carried out using the Geant4 Monte Carlo particle transport toolkit. Dose and dose equivalent rates, as well as penetrating particle spectra are presented. These results are based on detailed Geant4 ge...

A measurement of the double-differential cross-section for the production of charged pions in proton–tantalum collisions emitted at large angles from the incoming beam direction is presented. The data were taken in 2002 with the HARP detector in the T9 beam line of the CERN PS. The pions were produced by proton beams in a momentum range from 3GeV/c...

Detecting life in the Solar System is one of the great challenges of new upcoming space missions. One way to detect organic matter on extra-terrestrial objects could be the use of biochips. A biochip is composed of biological sensitive systems called ligands (like antibodies) fixed on a slide, which allow the detection of specific organic molecules...

For upcoming exploration missions, space agencies advocate the development of a new promising technique to search for traces of extent or extinct life: the biochip use. As space is a hazardous environment, a main concern relies on the resistance of this device to a panel of harsh constraints. Within the framework of the BiOMAS (Biochip for Organic...

23 pages, 26 figures.-- PACS nrs.: 95.55.Vj; 28.85.+c; 07.75.+h; 07.05.Kf; 14.40.Aq.-- ISI Article Identifier: 000245514100044 Printed version published on Mar 11, 2007. The particle identification (PID) methods used for the calculation of secondary pion yields with the HARP forward spectrometer are presented. Information from time of flight and Ch...

35 pages, 37 figures.-- PACS nr.: 95.55.Vj.-- ISI Article Identifier: 000244576000001.-- Available online 10 November 2006. HARP is a high-statistics, large solid angle experiment to measure hadron production using proton and pion beams with momenta between 1.5 and 15 GeV/c impinging on many different solid and liquid targets from low to high Z. Th...

The double-differential production cross-section of positive pions, d2sp+/d pdWd^2\sigma^{\pi^{+}}/d pd\Omega, measured in the HARP experiment is presented. The incident particles are 8.9GeV/c protons directed onto a beryllium target with a thickness of 5% of a nuclear interaction length. The measured cross-section has a direct impact on the predic...

Detecting life in the Solar System is one of the great challenges of new upcoming space missions. It implies to send new sophisticated devices to bodies of interest (like Mars) to try to perform in-situ measurements which will give hints of the presence, or lack, of organic matter. One of those devices could be a biological sensitive system called...

Predictions of Total Ionizing Dose made using full 3-D Monte Carlo and simplified sector-shielding techniques for simple and complex geometries in a space environment are compared and differences between them analyzed in detail