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Structure and Dynamics of Highly Charged Ions and Pionic Atoms Martino Trassinelli

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Structure and Dynamics of Highly Charged Ions and Pionic Atoms Martino Trassinelli Structure and dynamics of highly charged ions and pionic atoms Martino Trassinelli To cite this version: Martino Trassinelli. Structure and dynamics of highly charged ions and pionic atoms. Atomic Physics [physics.atom-ph]. Univesité Pierre et Marie Curie, Sorbonne Universités, 2017. tel-01674426v2 HAL Id: tel-01674426 https://tel.archives-ouvertes.fr/tel-01674426v2 Submitted on 15 Jan 2018 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Universit´ePierre et Marie Curie, Sorbonne Universit´es,Paris, France Habilitation `adiriger des recherches pr´esent´eepar Martino Trassinelli Charg´ede recherche CNRS (INP) Structure and dynamics of highly charged ions and pionic atoms Soutenue le 15 septembre 2017 devant le jury compos´ede : Jean-Michel RAIMOND Professeur (LKB, UPMC, Paris) Pr´esident Fr´edrich AUMAYR Professeur (IAP, Vienne) Rapporteur Jos´eR. CRESPO LOPEZ-URRUTIA´ Professeur (MPI, Heidelberg) Rapporteur Xavier FLECHARD´ Chercheur (CR1 avec HDR) (LPC, Caen) Rapporteur Eva LINDROTH Professeure (Univ. de Stockholm) Examinatrice Preface In this manuscript I present some of my research activities conducted during the past ten years starting from my hiring as researcher at the Centre National de la Recherche Scientifique (CNRS, National Center for Scientific Research) at the Institut des NanoSciences de Paris (INSP, Institute of NanoSciences of Paris). My research is carried out in the team Agr´egatset surfaces sous excitations intenses (ASUR, Clusters and Surfaces under Intense Excitation) and also with external collabora- tions: the atomic physics group of GSI Helmholtzzentrum f¨urSchwerionenforschung (GSI), and the Pion Hydrogen and Pion Mass collaboration. The work presented in this manuscript is the result of a teamwork without which the results discussed here would not have been possible. Except in this preface and when my contributions are expressly specified, all topics are presented as impersonal. Five chapters compose the manuscript. Chapter 1 is a general introduction. An overview of the different topics and the relationship between them in a general context are shortly presented. In the other chapters a selection of the most striking topics is detailed. Research activities on laser-cluster interactions [A11, C2, C8, C11, C13, C15], theoretical studies on ion{matter interaction [A10, C3] and plasma temperature measurements [A33] are not treated in this manuscript. Chapter 2 is dedicated to the data analysis methods. Two multipurpose analysis programs I developed in the last years are presented in this chapter. The first is based on the χ2 minimisation but with features that make it especially adapted for low-statistics spectra and where special functions can be included and employed for specific cases. The main feature of the second program is the possibility to compare different models describing the data and assign to them probabilities. This program is based on Bayesian statistics analysis methods that are introduced and presented as well in Ch. 2. Chapter 3 is dedicated to the measurement of the negatively charged pion mass using high-accuracy X-ray spectroscopy of pionic nitrogen and using a muonic oxygen transition as reference. In this chapter, I present, in particular, two particular aspects of the data analysis. The first one is the study of the line profile determined by the de-excitation cascade processes that occur after the creation of the bound system and the radiative emission of interest. The second one is the investigation of the presence or not of satellite lines due to the non-complete electron depletion. The presence of one or more electrons in addition to the pion, may cause, in fact, a shift of the radiative transition energies leading to a systematic effect. In chapter 4 I present the study of the collision of hydrogen-like argon with an atomic target at low velocity. Here, I focus on a particular aspect of the investigation: the atomic cascade processes and their comparison with theoretical predictions. The role of single- and multi-electron capture is revealed and the role of the presence of metastable states is evaluated. The effect of heavy and slow ion impact on giant magnetocaloric thin films is discussed in Chapter 5. This new subject, quite different from the others described in chapters 3 and 4, deserves specific i ii introductions on the ion{matter interaction and on the magnetocaloric effect. The description and characterisation of modifications induced by the ion irradiation in specific samples as manganese arsenide thin films are given. The results are discussed in a thermodynamical point of view that highlights the key role of the phase transition type (of first or second order) associated to the giant magnetocaloric effect. Finally, conclusions and perspectives of my future research projects are presented in the last part. Except for the general introduction, each chapter starts with an introductory section that ends with a specific part labeled in red where my personal contributions are presented with reference to my publication list. Integral texts of the most relevant publications associated to the different chapters are proposed in the appendices, together with auxiliary subjects. The manuscript is completed with my detailed curriculum vitae, the list of my oral contributions at conferences and workshops and the list of my publications. In the different chapters these publications are referred with a Latin letters and a progressive number: A for articles, B for book chapters, C for proceedings and D for patent. Other bibliographic references are indicated with simple numbers and can be found at the end of the document. Contents Preface i Contents iii 1 General introduction 1 1.1 General presentation . 1 1.2 Structure . 3 1.3 Dynamics . 5 1.4 Investigation methods . 9 1.5 Something completely different . 9 2 Statistics and data analysis methods and applications 11 2.1 Introduction . 11 2.2 A general fitting program: Minuit fit ........................... 12 2.3 Bayesian approach for data analysis . 16 2.4 The nested sampling for Bayesian evidence calculation . 21 2.5 A data analysis program based on Bayesian statistics: Nested fit . 24 3 The measurement of the mass of the negatively charged pion 27 3.1 Introduction . 27 3.2 Production of pionic and muonic atoms and detection of their radiative emission . 28 3.3 Spectral line shape . 32 3.4 Analysis of the data and discussions . 36 3.5 The new value of the charged pion mass . 43 4 Slow collisions between ions and atoms 47 4.1 Introduction . 47 4.2 Experimental set-up and methods . 49 4.3 Atomic cascade characteristics and modelling . 50 4.4 Discussions on the high-resolution spectra and comparison with theory predictions . 54 4.5 Final considerations . 59 5 Modification of properties of magnetocaloric thin films by ion irradiation 61 5.1 Introduction . 61 5.2 Ion { matter interaction . 62 5.3 Giant magnetocaloric effect and thin films . 66 iii iv Contents 5.4 Experimental methods . 75 5.5 Results and discussions of the ion irradiation effects . 77 5.6 Other samples and general discussion . 87 6 Perspectives 89 6.1 On the pion mass measurement . 89 6.2 Collisions of slow ions with atoms, clusters, surfaces and ions . 90 6.3 Giant magnetocaloric thin films irradiated with ions . 94 6.4 QED tests and dynamics collision with highly charged ions . 95 A Some recall on maximum likelihood and least-squares methods 97 A.1 The likelihood function . 97 A.2 Least-squares method and evaluation of parameter uncertainties . 98 B Classical over-the-barrier model 99 C Highly charged ion{surface interaction and other ion{matter processes 101 D Atomic cascade code for He-like ions 103 E Article about Bayesian data analysis methods 111 F Article about the pion mass measurement 125 G Article about ion{atom collisions 133 H Article about irradiation-induced modifications in magnetocaloric thin films 145 I Article about something completely different 151 Acronyms 165 Detailed Curriculum vitæ 167 Publications in international journals with referee comity 171 Book chapters 179 Proceedings with referee comity 181 Patents 185 Conferences and seminars 187 Bibliography 191 Chapter 1 General introduction 1.1 General presentation The activities presented in this manuscript are centred on pionic atoms (hydrogen-like atoms where electrons are substituted with a negatively charged pion) and highly charged ions (HCI) (atoms with high atomic number Z and only one or a few electrons). These atomic systems, apparently very different, are sharing many common features and their investigation is carried out thanks to similar characterisation techniques. If we consider the typical level energies En and electric fields of any E 1017 1016 1015 ) m 1014 c / V ( 1013 Max. Laser field 1012 1011 1010 0 25 50 75 100 Nuclear charge Z Figure 1.1 { Left: Average electric field relative to the 1s level as a function of the nuclear charge Z. As comparison, the value of the electric field of the most powerful available lasers is indicated in red. Right: Different QED and nuclear size effects as a function of the nuclear charge Z. 1 2 1. General introduction Highly charged ions and pionic atoms Structure Dynamics (A) (B) (C) (D) (E) (F) Interaction Nucleus and Collisional Decay Target Target forces particles(s) processes processes characterization modification Figure 1.2 { Scheme of the research topics presented in the manuscript. atomic system that are1 2 2 3 2 (Zα) 4 m c 3 En = mc + (Zα) and (Zα) ; (1.1) 2n2 O E ∼ e~ (where m is the reduced mass of the system, c the speed of light, α the fine constant, e the electron charge, ~ the reduced Planck constant and n the principal quantum number) we see that a larger mass of the orbiting particle or a high of the nuclear charge causes a considerable increase of En and .
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