29131 - IMAGING AND SPECTROSCOPY LM

Conoscenze e abilità da conseguire

At the end of the course, the student will learn how to take advantage of scanning electron microscopy (SEM) techniques as well as of elemental (EDS and XRF) and structural (Raman, IR) microanalysis systems for the study of materials. In particular, the student will be able to: (a) set up an investigation campaign, (b) choose the best working conditions as a function of the material characteristics and (c) correctly evaluate the results.

Contenuti

PART I: ELECTRON MICROSCOPY

Introduction

Introduction to Electron Microscopy: a brief history.

Electron optics

Electron beam generation: thermoionic (W and LaB6) and field emission guns, cathode comparison.

Electron beam lenses and apertures. Beam alignment, deflections and aberrations.

Electron beam / specimen interactions

Interaction volume: influence of beam and specimen parameters. Secondary electron emissions, transmitted electrons, induced specimen current, backscattered electron emission, Auger electron emission, X-ray emission.

Image formation and interpretation

Image construction: secondary (SE), backscattered (BSE) and transmitted (TE) electrons. Detectors, compositional and topographic contrast formation, image quality. Variable pressure and environmental electron scanning microscopy. Electron backscattering diffraction (EBSD).

Elemental analysis

Generation of X-rays. Spectral measurements: Energy dispersive and wavelength dispersive spectrometers (EDS, WDS). Qualitative and quantitative analyses. X-ray mapping and line scan.

 

PART II: MICROSCOPIC AND SPECTROSCOPIC IMAGING

Raman Microscopy

A brief history of the Raman effect, classical and quantum-mechanical description.

Polarisation, Raman resonance, fluorescence, confocality.

Instrumentation: Dispersive and FT spectrometers, coupling microscope-spectrometer.

IR Microscopy

A brief history and fundamentals of infrared spectroscopy.

Instrumentation: double beam IR spectrometer, FT-IR spectrometer, coupling microscope-spectrometer.

IR techniques: transmission, reflection, near-normal reflection absorption, ATR.

XRF Microscopy

A brief history and fundamentals of X-Ray fluorescence.

Instrumentation: device structure, X-Ray generation, detectors, sample chamber, coupling microscope-spectrometer.

Qualitative and quantitative analyses, confocality.

Imaging Spectroscopy

Direct imaging, series imaging, signal-to-noise ratio (S/N) and collection time .

Raman imaging (line scanning, mapping, confocal imaging); IR imaging; Fluorescence imaging.

Quantitative chemical distribution, surface topology.

 

PART III: COUPLED TECHNIQUES AND APPLICATIONS TO MATERIALS SCIENCE

Imaging and analyses by coupling of Raman Spectroscopy, Energy Dispersive Spectroscopy and Scanning Electron Microscopy.

Sample preparation : metals, ceramics, minerals, semiconductors, polymers (film and membranes, resins and plastics), biological materials.

Applications and case studies.

Testi/Bibliografia

Course material (slides and notes).

• Goldstein et al., Scanning Electron Microscopy and X-Ray Microanalysis,  Kluwer Academic, 2003
• Handbook of Vibrational Spectroscopy (ed. by J.M. Chalmers, P.R: Griffiths) J.Wiley, 2002
• J.M. Hollas, Modern Spectroscopy, J.Wiley & Sons, 1992

Metodi didattici

Lectures and practicals according to the timetable.

Modalità di verifica e valutazione dell'apprendimento

Oral examination .

Strumenti a supporto della didattica

PC and projector, blackboard. Access to research labs (SEM/EDS+Raman; IR)

Orario di ricevimento

Consulta il sito web di Carla Martini