Chris Jeynes, University of Surrey Ion Beam Centre
There have been remarkably wide-ranging and interesting applications of PIXE recently involving innovative detectors and software, of which I cite a selection. We believe that an opportunity to discuss the development of the field would be valuable for the community. We welcome those interested to make three minute presentations of their comments to the issues summarised below, or of any other issues they believe may be relevant. Early notice of such presentations to me will enable Abstracts to be published on the website.
There are detector developments and software developments, but I believe a wider view should be taken: which new applications do the improved detectors serve? how do we use the software advances to support better protocols for spectrometry (and spectroscopy)? Ion Beam Analysis (including PIXE) confronts the danger of a mature field: being overtaken by the enthusiastic development of younger, but very powerful, techniques (which today proliferate). How much difference will a proper use of PIXE make to the world? And can we get excited about it? I hope this Round Table will reflect the excitement I feel.
Reports of new codes (PAMPA, Argentina, JAAS 2017i), are encouraging since they indicate the perceived importance of the field. But imaging, chemical speciation, and progress in quantitation (spectrometry) are central to recent developments. Detectors include the classical Si(Li) devices, now largely replaced by SDDs, with Si array detectors (Maia or CCD) for high speed, and CdTe (or HPGe) available for higher energies. Superconducting devices look likely fairly soon to be feasible for routine high resolution analysis.
Ebrahim Hatan, from Iran, continues his campaign to popularise the imaging of voids with stereo-PIXEii. The French are continuing to display their leading imaging and analysis capabilities with a detailed study on mediaeval glasses (Anal.Chem. 2017iii) and a careful treatment of Total-IBA uncertainties (Measurement 2018iv). The Italians (Anal.Chem. 2016v) and the Germans (XRS, 2018vi) are using CCD X-ray cameras with capillary lenses to obtain instant imaging without scanning. The Australians continue to use their MAIA detector (J. Synchr. Rad. 2018vii), in this case for XANES imaging but of course GeoPIXE has both XRF and PIXE modules. And the Brazilians are revisiting old attempts at properly quantitative approaches to large imaging datasets in a way that may prove highly useful (XRS 2018viii).
Chemical speciation is accessible though high resolution PIXE, which may be through the classical WDX methods (see the work from the Slovenian acceleratorix) or the new 3rd generation TES (EDX) detector arrays (Finland, XRS 2018x), with valuable basic work still being reported from 1st generation TES devices (Portugal)xi.
I would like to draw people’s attention to the careful attention given to calibration protocols by the Lisbon groupxii, and the extraordinary and beautiful use of extra-terrestrial XRF/PIXE data to demonstrate spectrometry non-linearity by the Guelph groupxiii. The latter also demonstrate that multiple ionisation satellite lines become significant for α-PIXE. These developments are aimed at accuracy in PIXE, essential for any fully quantitative technique. Note also that Total-IBA is underpinned by the accuracy of RBS, which has recently been demonstrated a Primary Reference methodxiv, and used to accurately determine absolute photo-ionisation cross-sections of Gaxv.
i T. Rodríguez, S. Limandri, S. Suárez, I. Ortega-Feliud, J. Trincavelli, Standardless semi-quantitative analysis by PIXE, J. Analytical Atomic Spectrometry, 2017, 32, 1020-1030; DOI: 10.1039/c7ja00068e
ii Ebrahim Gholami Hatam, Void and cavity determination in micro-PIXE analysis of composed material using binocular detectors: A computational study, Nuclear Instruments & Methods in Physics Research B 404 (2017) 189–192; DOI: 10.1016/j.nimb.2017.01.066
iii Myrtille O. J. Y. Hunault, Claudine Loisel, Fanny Bauchau, Quentin Lemasson, Claire Pacheco, Laurent Pichon, Brice Moignard, Karine Boulanger, Michel Hérold, Georges Calas, and Isabelle Pallot-Frossard, Nondestructive Redox Quantification Reveals Glassmaking of Rare French Gothic Stained Glasses, Analytical Chemistry 2017, 89, 6277-6284; DOI: 10.1021/acs.analchem.7b01452
iv M. Radepont, Q. Lemasson, L. Pichon, B. Moignard, C. Pacheco, Towards a sharpest interpretation of analytical results by assessing the uncertainty of PIXE/RBS data at the AGLAE facility, Measurement 114 (2018) 501–507; DOI: 10.1016/j.measurement.2016.07.005
v Francesco Paolo Romano, Claudia Caliri, Luigi Cosentino, Santo Gammino, David Mascali, Lighea Pappalardo, Francesca Rizzo, Oliver Scharf, Hellen Cristine Santos, Micro X‑ray Fluorescence Imaging in a Tabletop Full Field-X-ray Fluorescence Instrument and in a Full Field-Particle Induced X‑ray Emission End Station, Anal. Chem. 2016, 88, 9873−9880; DOI: 10.1021/acs.analchem.6b02811
vi Josef Buchriegler, Nico Klingner, Daniel Hanf, Frans Munnik, Stanisław H. Nowak, Oliver Scharf, René Ziegenrücker, Axel D. Renno, Johannes von Borany, Enhancements in full-field PIXE imaging—Large area elemental mapping with increased lateral resolution devoid of optics artefacts, X-Ray Spectrometry, 2018; 47:327–338; DOI: 10.1002/xrs.2946
vii Ulrike Boesenberg, Christopher G. Ryan, Robin Kirkham, Andreas Jahn, Anders Madsen, Gareth Moorhead, Gerald Falkenberg and Jan Garrevoet, Fast XANES fluorescence imaging using a Maia detector, J. Synchrotron Rad. (2018). 25, 892–898; DOI: 10.1107/S1600577518004940
viii Tiago F. Silva, Gustavo F. Trindade, Marcia A. Rizzutto, Multivariate analysis applied to particle‐induced X‑ray emission mapping, X‐Ray Spectrometry, 2018; 47:372–381; DOI: 10.1002/xrs.2953
ix Matjaž Kavčič, Marko Petric, Katarina Vogel-Mikuš, Chemical speciation using high energy resolution PIXE spectroscopy in the tender X-ray range, Nuclear Instruments and Methods in Physics Research B, 417 (2018) 65–69; DOI: 10.1016/j.nimb.2017.06.009
x Marko Käyhkö, Mikko R. J. Palosaari, Mikko Laitinen, Kai Arstila, Ilari J. Maasilta, Timo Sajavaara, Heavy ion induced Ti X-ray satellite structure for Ti, TiN, and TiO2 thin films X-Ray Spectrometry, 2018; 47: 475‑483; DOI: 10.1002/xrs.2976
xi P.C. Chaves, M.A. Reis, H+, O2+, O3+ and high resolution PIXE spectra of Yb2O3, Nuclear Instruments and Methods in Physics Research B, 410 (2017) 193–199; DOI: 10.1016/j.nimb.2017.08.026
xii A.P.L. Bertol, P.C. Chaves, R. Hinrichs, M.A.Z. Vasconcellos, M.A. Reis, Methodology for a fast determination of EDX Si(Li) detector response function in the 5 keV to 15 keV range, Nuclear Inst. and Methods in Physics Research, A 908 (2018) 394–400; DOI: 10.1016/j.nima.2018.08.115
xiii John L. Campbell, Christopher M. Heirwegh, Brianna Ganly, Non-linearity issues and multiple ionization satellites in the PIXE portion of spectra from the Mars alpha particle X-ray spectrometer, Nuclear Instruments and Methods in Physics Research B 383 (2016) 143–151; DOI: 10.1016/j.nimb.2016.07.004
xiv C.Jeynes, RBS as a new primary direct reference method for measuring quantity of material, Nuclear Instruments and Methods in Physics Research B, 406 (2017) 30-31; DOI: 10.1016/j.nimb.2016.11.041
xv Rainer Unterumsberger, Philipp Hönicke, Julien L. Colaux, Chris Jeynes, Malte Wansleben, Matthias Müller and Burkhard Beckhoff, Accurate experimental determination of gallium K- and L3-shell XRF fundamental parameters, J. Anal. At. Spectrom., 33 (2018) 1003-1013; DOI: 10.1039/c8ja00046h