External Beam IBA Measurements for Cultural Heritage

Round 1

Reviewer 1 Report

The paper “External beam IBA measurements for cultural heritage” by Massimo Chiari reviews the basic principles of IBA techniques (PIXE, and PIGE and RBS/EBS), mostly implemented in external beam setups and their application for the determination of chemical composition and depth profiling of cultural heritage artefacts. The paper provides some technical details and hints on how these techniques can be used to answer various questions from cultural heritage field.

The paper is generally well-written, equipped with a set of illustrative figures and supported by an extensive bibliographic list. It is worth mentioning some older references, reporting ideas/practical solutions that were successfully implemented for the first time and brought to the attention of IBA community.

Below are given some minor and language corrections that will hopefully improve the clarity of the presentation and prevent annoying repetitions of some words.

Lines 13-14: “IBA techniques can be performed while maintaining the object to be investigated at atmospheric pressure/without placing it in vacuum/in an analysis chamber”;

Lines 14-15 – “avoiding the need of invasive sampling”;

Lines 27-28 – word “heritage” is repeated in the same phrase;

Line 27 – not “always”, but for a long period of time…several decades…because the subject of this sentence is too generous: “Nuclear physics”!;

Line 29 – “and played a role”;

Line 48 – “…are non-destructive and, in principle, do not require any sample extraction, preparation or pre-treatment…”

Line 50 – “However, they probe only the surface of the material – the first tens of microns, depending on the range of the bombarding charged particles, that, in turns, depends on the type of matrix...”;

Lines 57-60 – a bit messy paragraph, please, rephrase;

Line 83 – “not deliberately destructive”, maybe…

Line 89 – “to reduce the attenuation of low-energy X-ray photons in air”;

Line 103 – “killer application” – a term that is a bit far-fetched considering the context;

Line 111 – SRM is a term applicable only to the certified reference materials (CRM) produced and sold by NIST only – therefore, I suggest CRM instead of SRM;

Lines 134-136 - “choose a detector with a large active area (…) and a thin entrance window”;

Line 137 – “With respect to the X-ray detectors…”;

Line 145 – Mn Kalpha line – do not forget the subscript;

Line 147 – “just a Peltier cooling element”;

Line 156 – before or reference [9], i.e. C. Pacheco, Q. Lemasson, B. Moignard, L. Pichon, M. Radepont, D. Gourier, Techne 43 (2016) 63, it would be advisable to add the following one, the one in which the New AGLAE setup was actually published:

L. Pichon, B. Moignard, Q. Lemasson, C. Pacheco, P. Walter, Development of a multi-detector and a systematic imaging system on the AGLAE external beam, Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms. 318 (2014) 27–31. https://doi.org/10.1016/j.nimb.2013.06.065.

Line 165 – “can be still obtained”;

Sub-chapter Differential PIXE – please, do comment on the applicability of this analytical approach compared to RBS/EBS – according to your case study and maybe the comment from  lines 328-330;

Line 225 – K not ° /degree K – K (only the letter) is the symbol for Kelvin degrees, unlike C or F degrees;

Line 255 – “with negligibly” or “practically very little attenuation”;

Lines 361-366 – the charge-related measurements using the Ar signal from air are discussed in the papers of Ziga Smit, who also published an impressive number of papers on CH items analyzed with external IBA;

Conclusions – maybe you should comment on the fact that the until now, any portable and/or transportable equipment (e.g. pXRF) does not offer the same performances as IBA with respect to the detection limits; moreover, light elements are not easily measurable and quantifiable using many analytical methods – therefore the special impact of PIGE and/or NRA, the latter an IBA method not mentioned in this paper;

Line 437 – Pichon, not Pinchon in reference [5], namely T. Calligaro, V. Gonzales, L. Pichon, Nucl. Instr. and Meth B 363 (2015) 135

As a general comment, some other references might be added, mentioning the investigations performed using external IBA setups on CH items in other laboratories (e.g. Sevilla, Ljubljana, Zagreb, Athens, Debrecen, Lisbon, Madrid, Dresden – but not only)! – to ease any potential user/reader from CH field in an eventual search of lab(s) where such measurements were or can be performed… there are many NIMB papers on this topic.

Author Response

I thank the reviewer for his/her appreciation and for his/her constructive comments and for spotting some language errors in the text.

All the some minor and language corrections have been implemented.

All the comments have been incorporated in the manuscript.

As suggested, references mentioning the application of IBA techniques on cultural heritage objects using external beam set-ups have been added, not only from the list of suggested laboratories but including some others as well.

Moreover, the editing of the manuscript has been completed, for instance adding missing keywords, fundings and acknowledgments. Figures and tables have been formatted according to the journal guidelines as well. 

Reviewer 2 Report

This paper is basically a review article on the capabilities and drawbacks of IBA external beam set-ups and on the advantages of combining several IBA (in particular PIXE, PIGE and EBS/RBS) techniques for a more profound knowledge on the samples under analysis in particular when measuring cultural heritage artefacts. Based on the author’s and lab team developed expertize, the information contained in the manuscript can guide other researchers on the proper development of their own system and shows to conservators and/or curators the information possible to extract from IBA external beam analysis. For these reasons I feel that the manuscript should be published after what I can call some minor revisions. On the English writing quality, I should say that some sentences are difficult to understand maybe because they are too long and on that account some careful revision should be made. Apart from that, I think the author could have presented to the editor and reviewers a more “clean” manuscript (instruction for authors maintained in the text; no keywords; no funding agencies; no acknowledgments).

In order to improve the manuscript quality I will mention some typos, comments and suggestions that can be found in the uploaded annotated version of the manuscript.

Comments for author File: Comments.pdf

Author Response

I warmly thank the reviewer for his/her appreciation, and for his/her constructive comments and for spotting some errors in the text.

Calculations have been reviewed and when necessary corrected.

A discussion on the effects of backscattered protons on X-ray detectors has been included.

All the typos have been corrected and the editing of the manuscript has been completed, for instance adding keywords, fundings and acknowledgments. Figures and tables have been formatted according to the journal guidelines as well.