Physics

MARIA GRAZIA BETTI

GENERAL OBJECTIVES:
The main objectives of Physics laboratory I are:
i) knowledge of the physical principles of the interaction between electromagnetic radiation or particles with matter, of the working principles for particle sources and detectors;
ii) knowledge of the laboratory techniques and of their basic principles, in order to prepare a laboratory experience during Physics Laboratory II.
At the end of the lectures, students will develop the attitude to quantitatively approach the experimental techniques to study the phenomena associated with (depending on the chosen track) elementary particles, condensed matter and biophysical properties. Moreover, students will be able to:
- identify the assumptions underlying an experimental measurement
- identify and explain the limitations of the hypothesis behind the experimental measurements.

Additional objectives for the particle-physics course: knowledge of the basic principles of gas detectors, of solid state detectors, of electromagnetic calorimeters, of particle identification techniques (also based on the Cherenkov effect), of magnetic spectrometers, and of photosensors (as PMT, photodiodes and similar devices). Additional objectives for the condensed-matter and biophysics courses: knowledge of the foundations of electron ad x-ray diffraction techniques, scanning probe microscopy at the atomic scale, optical and Raman spectroscopy, photoelectron spectroscopy, synchrotron radiation and x-ray absorption.

SPECIFIC OBJECTIVES:
A - Knowledge and understanding
OF 1) To know the basic principles of modern experimental techniques in physics
OF 2) To understand the orders of magnitude of the relevant experimental quantities
OF 3) To know the field of application of modern experimental techniques
B - Application skills
OF 4) To be able to deduce which experimental technique is useful to solve a given problem
OF 5) To be able to solve problems of estimate of experimental performances in terms of e.g. resolution (space, spectral, time) or probe energy.

C - Autonomy of judgment
OF 6) To be able to evaluate the feasibility of an experiment, broadly described.
OF 7) To be able to integrate the knowledge acquired in contexts outside the field of physics (e.g. computer science, genetics, materials science, …)


D - Communication skills
OF 8) To be able to communicate with an experimentalist (if the student is a theoretician) or to know what a theoretician knows about the experiments (if the student is an experimentalist)
OF 9) To be able to participate to a scientific conference in which experimental data are discusses, both as a member of the audience and as a presenter, even if the student has never employed these techniques.

E - Ability to learn
OF 10) Have the ability to consult a scientific publication, in which modern experiments are described or just referred to.
OF 11) Being able to conceive and develop a Master thesis project with an experimental chapter that could be either a description of an experimental activity actually performed or a literature search / state of the art / data analysis.
SPECIFIC OBJECTIVES:
A - Knowledge and understanding
OF 1) To know the basic principles of modern experimental techniques in physics
OF 2) To understand the orders of magnitude of the relevant experimental quantities
OF 3) To know the field of application of modern experimental techniques

Knowledge of the physical principles of the interaction between electromagnetic radiation and particles with matter, of the working principles for sources and detectors. Knowledge of the laboratory techniques and of their fundamentals, in order to prepare a laboratory experience on the following course Physics Laboratory II, of the specific specialty.
In particular, for the Physics of Condensed Matter, knowledge of the foundations of electron ad x-ray diffraction techniques, scanning probe microscopy at the atomic scale, optical and Raman spectroscopy, photoelectron spectroscopy, synchrotron radiation and x-ray absorption.
At the end of the lectures, students will develop attitude to quantitatively approach the experimental techniques to study the phenomena associated to the condensed matter properties.

Knowledge of the fundamentals of the Structure of Matter, as learnt in the first level Laurea courses
• Knowledge of the fundamentals of Electromagnetism, as learnt in the first level Laurea courses

Syllabus

1. General issues on spectroscopy
Physical quantities and measurement units – Maxwell equation in a medium – Polarization - Brief introduction to the linear response theory – Interaction of the electromagnetic radiation with matter - Complex spectroscopy functions - Complex dielectric function – Polarization and response with the Lorentz model, semiclassical and quantum models - Reflectivity and absorption coefficient – Dipsersion relations and causality, Kramers-Kronig relations – Fluctuation-dissipation theorem [for ex. Wooten, chapt. 2,3,6,8; Kittel, chapt. 3,4; notes on the web site]

2. Diffraction from a crystal
Brief introduction to the crystalline systems - Bravais lattices - Symmetries – Diffraction, Thomson scattering, the structure factor; diffraction techniques, reciprocal lattice, X ray, electron, neutron diffraction
[for ex. Kittel, chapt. 1,2]

3. Imaging and spectroscopy techniques at the atomic scale
Scanning Tunneling Microscopy (STM) and Spectroscopy (STS) - Atomic Force Microscopy (AFM)
[notes on the web site]

4. Anelastic scattering techniques
Inelastic neutron scattering - Rayleigh e Raman light scattering - anelastic X-ray scattering
[notes on the web site; Wiesendanger, chapt. 1.1, 1.11, 1.13, 2, 2.1, 2.4, 2.7]

5. Electronic band structure of exemplary crystalline systems
Band structure of metals (simple, noble, transition), semiconductors (group IV, III-V), graphene and graphite, boron nitride
[for ex. Bassani, chapt. 4]

6. Optical spectroscopy
Absorption and reflectivity measurements - Sources of electromagnetic radiation – Principles of laser operation - Synchrotron radiation - Analyzers: monochromators - Detectors of e.m. radiation
[for ex. Wooten chapt. 5,9; Bassani, chapt. 5; notes on the web site]

7. Photoelectron spectroscopy and X ray absorption
The photoemission technique - XPS and UPS - ARPES - X ray absorption, XAS (NEFAXS) and EXAFS techniques
[notes on the web site; Mariani-Stefani book chapter]

8. Fundamentals of vacuum techniques
Measurement of low pressures - Vacuum pumps, vacuum pipes, vacuum gauges [notes on the web site]

Textbooks and bibliography

- F. Bassani, G. Pastori-Parravicini, “Electronic States and Optical Transitions in Solids”; chapters 4, 5.
- C. Kittel, “Introduzione alla Fisica dello Stato Solido”, Ed. CEA, 2008, chapters 1, 2, 3, 4.
- Carlo Mariani and Giovanni Stefani, “Photoemission Spectroscopy: Fundamental Aspects”, Chapter 9, pp. 275-317, in Synchrotron Radiation: Basics, Methods and Applications. Editors: Settimio Mobilio, Federico Boscherini, Carlo Meneghini. Springer, 2015. doi:10.1007/978-3-642-55315-8
- R. Wiesendanger, “Scanning Probe Microscopy and Spectroscopy”, chapters 1.1, 1.11, 1.13, 2, 2.1, 2.4, 2.7
- F. Wooten, "Optical Properties of Solids", Academic Press, 1972; chapters 2, 3, 5, 6, 8, 9
- notes available on the web site: https://elearning.uniroma1.it/course/view.php?id=6367

Scientific papers and reviews on the experimental techniques.

Lectures, description of the experimental instruments and discussions

Participation to the explanations and discussions.

Discussion about the experimental techniques shown during the course.

The examination consists of an oral test in which the students’ questions will be asked about the topics covered by the course. To pass the exam, students must master the different ones technical experimental presented in class.

Students must answer to a few questions to verify their knowledge of the syllabus and/or queries (also with numerical solutions) to quantify their in-depth knowledge. The evaluation will take into account:
- correctness of the exposed concepts;
- clarity and rigor of presentation;
- ability to analytic development.

Students who answer in a sufficient way to the questions without being able to resolve the queries will be scored with 18/30; students who answer in a good way to the questions and are able to propose a solution to the queries will be scored up to 24/30; students who answer in a very good way to the questions and can precisely describe the solutions of the queries will be scored up to 27/30; students who demonstrate a full knowledge of the syllabus, with an exact solution of all the queries, also showing a critical approach, will be evaluated up to 30/30 cum laude.

Description of the experiments in the research laboratories