Report by Ian Vickridge
The First RADIATE Summer School was held in Paris, France, at the auditorium of the Centre de Restoration et de Recherche des Musées de France (C2RMF), in the Palais du Louvre, from 10 to 11 October 2019. It immediately preceded the 24th International Conference on Ion Beam Analysis, which was held in Antibes from 14 to 18 October. Participants of the summer school had the chance to attend the subsequent IBA Conference tutorial on 12 October.
The first two days of tutorials aimed to give a solid base of the physics underlying Ion Beam Analysis. On Day 1, the basics of collision physics were presented, leading to derivation of basic relations for quantities such as the kinematic factor for elastic collisions, the Rutherford cross section, the Bohr stopping power with explanations of the various refinements that were made to this by Bethe, Bloch, and others, and the fundamentals of ionization and de-excitation of atoms – the basic processes leading to x-ray emission (PIXE), amongst other things.
After the final lecture, a dozen or so participants made short (5-10 minutes) presentations of the work or research projects. This exercise was well respected by the participants (a maximum of 5 slides) and appreciated not only by the participants, but also by the lecturers who were present. The rest of the participants presented their work during a similar session on Day 2.
Day 2 was dedicated to tutorials on the practical realization of IBA techniques, starting with the widely used elastic scattering techniques, then PIXE and finally NRA and PIGE. The final lecture was a presentation of the main ideas and some cases underlining the estimation of uncertainties in quantities measured by IBA. It was particularly satisfying to see this presented to early stage researchers, since often uncertainty estimates are only made as a last touch after a series of experiments, whereas IBA is a quantitative method that merits serious attention being paid to uncertainty estimates.
Although initially not foreseen, it was possible to organise a visit to the C2RMF restoration and research laboratories, including the AGLAE accelerator dedicated to IBA for cultural heritage.
The Friday evening Summer School dinner was held at the Lycée Jean Drouant training restaurant in central Paris. A gourmet meal, cooked by trainee chefs and served by trainee waiters in an Art Deco décor reminiscent of the liner ‘Normandy’, was very much appreciated by the Summer School participants.
The Summer School was attended by 23 participants from 11 countries. The Tutorials on Applications of IBA on Saturday 12 October were in addition attended by a further 25 participants, and the topics presented lead to lively discussions, in particular with regards to to the place of ERDA as a ‘the most powerful ion beam technique in materials science’.
It is my great pleasure to sincerely thank all of the lecturers, who prepared clear presentations that were greatly appreciated by the Summer School and Tutorial participants. I would also like to thank the participants themselves, for their interest in the courses and their willingness to participate, through their presentations and also through their questions and the resulting discussions.
Ian Vickridge
Program of the RADIATE summer school 2019
Thursday, 10 October 2019
Introduction and Course Outline (I. Vickridge)
Lecture 1: Collisions
Lecture by Ian Vickridge
Institut des NanoSciences de Paris, CNRS and Sorbonne University, France
The physics of collisions between a rapid ion and the atoms of a sample to be analysed are at the heart of Ion Beam Analysis (IBA). This lecture will present the elementary physics of elastic and inelastic ion-atom collisions at small impact parameters – kinematics and cross-sections – developed in particular for application to Rutherford Backscattering Spectrometry (RBS), Elastic Recoil Detection Analysis (ERDA) and Nuclear Reaction Analysis (NRA).
Coffee break
Lecture 2: Stopping Power
Lecture by Ian Vickridge
Institut des NanoSciences de Paris, CNRS and Sorbonne University, France
In addition to the small impact parameter collisions introduced in Lecture 1, rapid ions undergo a multitude of collisions with the electrons in the matter they traverse, resulting in a practically continuous energy loss along the ion trajectory. This is characterised by the Stopping Power of the material for the ion and is at the heart of the concentration depth profiling capabilities of IBA techniques. This lecture will address the basic underlying physics of stopping power and the various analytic and semi-empirical models which may be applied in IBA.
Lunch break
Lecture 3: Collisions of fast ions with atoms
Lecture by Feraz Dias
Ion Implantation Laboratory, Federal University of Rio Grande do Sul, Porto Alegre, Brazil
The present lecture deals with the excitation of the atom through ionization induced by charged particles and subsequent de-excitation processes. In particular, this lecture will cover the following topics:
- Historical aspects of atomic physics;
- Ionization processes;
- Fundamentals of de-excitation processes:
- Coster-Kronig transitions;
- Auger electrons;
- Characteristic X-rays emission;
- Spectroscopy with electrons and X-rays;
Coffee break
Participant Presentations : session I
Summer School Dinner
Friday, 11 October 2019
Participant Presentations : session II
Lecture 4: RBS/EBS and ERDA
How elastic scattering and recoil of ions can be used for materials analysis and depth profiling
Lecture by Iva Bogdanovi? Radovi?,
Ru?er Boškovi? Institute, Zagreb, Croatia
This Lecture will explain the basic physics principles on which two Ion Beam Analysis (IBA) methods, Rutherford/Elastic Backscattering (RBS/EBS) and Elastic Recoil Detection Analysis (ERDA) rely. Also, different experimental setups that can be used for the measurements, from very simple to sophisticated ones will be described.
Today both techniques are an essential tool for analysis of wide classes of materials, from archaeological objects, thin films and coatings to the materials for future fusion reactors. In the lecture different examples of materials analysis and depth profiling using RBS/EBS and ERDA will be presented. Advantages and disadvantages of using them in some particular cases will be also emphasised.
Coffee break
Lecture 5: PIXE
Lecture by Thomas Calligaro
Centre de Recherche et de Restauration des Musées de France, Palais du Louvre, Paris France
This lecture covers the practical application of PIXE, including experimental setups and their optimisation for specific applications both in vacuum and with extracted beams. The analytical performance of PIXE – detection limits and quantification will also be addressed
Lunch break
Lecture 6: NRA and PIGE
Lecture by Hicham Khodja
Laboratoire d’Etude des Elements Legers (LEEL), Commisariat de l’Energie Atomique, Saclay, France
This lecture will address the practical implementation and performance of Nuclear Reaction Analysis and Particle-Induced Gamma emission for application to the analysis of light elements.
Coffee break
Lecture 7 Uncertainty, Precision and Accuracy in IBA
Lecture by Professor Chris Jeynes
University of Surrey Ion Beam Centre, Guildford, England
Course Summary
- The International Vocabulary of Metrology (VIM) definition of terms: a Measurement must include an estimate of its Uncertainty
- Life is uncertain in principle, but error is to be avoided if we can (NB: always include error-bars in figures!)
- Distinction between Precision and Accuracy. Distinction between Repeatability and Reproducibility
- These issues are important in IBA precisely because Quantitation is its great strength
- Type A and Type B uncertainties: see the Guide to the Expression of Uncertainty in Measurement (GUM)
- Uncertainty Budget (also see GUM)
- Absolute accuracy of RBS (best achieved to date)
- Accuracy of thick-target PIXE
- Accuracy of EBS, ERD, NRA
- Accuracy of Total-IBA
- Exercises