An Evaluation of Three Halogens (Cl, Br, and I) Data from a Geological Survey of Japan Geochemical Reference Materials by Radiochemical Neutron Activation Analysis

Round 1

Reviewer 1 Report

Given in the attached file Review(1).pdf.

Comments for author File: Comments.pdf

Needs improvements. Some suggestions given in the attached file Review(1).pdf.

Author Response

We highly appreciate thorough and constructive comments. Let us describe here how we responded to them one by one. The revised portions are shown in red in the revised manuscript.

Author Response File: Author Response.docx

Reviewer 2 Report

This paper describes INAA and RNAA measurements of geological specimens, and compares results with literature values of the same techniques as well as those of a few other analytical techniques. The study shows the complexity of these measurements and the difficulty of harmonizing results from different techniques. This study uncovers problems and provides useful information for better experimental design in the future.

Main concern:

The only two overlapping measurements for the two standards JCP-1 and JSO-1 are important in this study.  For JSO-1, INAA has good agreement with RNAA, but for JCP-1 does not. The authors attribute this to within-sample heterogeneity.  This may or may not be the reason since INAA effectively takes a bulk average. Between-sample heterogeneity is another matter.

Please consider the following: JCP-1 has about double the mass of JSO-1, as noted by the discussion in 3.2.1.  (In addition, JCP-1 has 4 times the Cl mass fraction of JSO-1.)  The RNAA values for JCP-1 are higher than INAA for all three elements, which would suggest that INAA could be losing signal due to gamma attenuation, which is likely proportional to sample mass.

Please discuss this and other possible reasons of bias due to mass quantities, which perhaps can be a topic of future study -- control for sample mass and elemental abundance.  

A second request:  Please add standard error of the mean to each line (red, black, and blue) in Fig. 1.  The figure caption mentioned "shaded area" but it's not seen in Fig. 1.

A third request: Please add a bit more of the INAA irradiation conditions, estimated thermal neutron flux, and whether there is a flux monitor for each irradiation.  

Just my personal preference -- "higher" detection limit, "larger" repeatability maybe technically correct but could give a wrong impression.  Consider using "poorer" or "worse".

Author Response

We highly appreciate thorough and constructive comments. Let us describe here how we responded to them one by one. The revised portions are shown in red in the revised manuscript.

Author Response File: Author Response.docx

Reviewer 3 Report

Dear Authors!

Despite the fact that the research is very valuable for the characterization of reference samples, in my opinion, the measurements taken are slightly insufficient for full conclusions.

·         The repeatability assessment was carried out using only a single sample (it is not clear how it was selected), while the article mentions that the samples have a diverse composition, and it would be very useful to provide repeatability data for samples with the minimum and maximum content of each halogen. This would really make the article more valuable.

·         The conclusion about the consistency of the methods was made, in fact, based on the analysis of a single sample (JSO-1), while for the JCp-1 sample the data did not agree well (especially for Cl). It would be necessary to increase the number of samples for comparison, or, for example, to provide these data separately for each element. I understand that INNA method is complicated for Br and I with low content, however, Cl can be analyzed in almost the all listed samples. Also, I recommend adding estimation of standard deviation between obtained results for each element.

·         Some measurements were taken once, others twice. It would be more reliable to make two measurements for all samples (and use two measurement for JR-3 differently from repeatability estimation).

·         It is unclear how the methods and samples were selected. This information is given only in sections 3.1 and 3.2. These sections contain data that would be more appropriately mentioned in the «introduction», «samples» or «methods «sections, before the measurement results are given.

Here are a few minor comments:

1.       Provide values for repeatability in the abstract (line 22)

2.       Delete the first sentence of the introduction, this is obvious.

3.       It is unclear how the chemical reference samples (line 71-78) were used. Please expand this part. Were calibration equations constructed? This may not be clear to a non-NAA specialist.

4.       Throughout the text, various measurement conditions are mentioned (15 sec at 1MW or 3 sec at 5 MW, line 95; 5 to 15 min ... 20 to 60 min, line 98, 10 min at 1MW or 2 min at 5MW, line 107, 2 to 20 min, line 128, etc.). Specify everywhere in which cases which conditions were chosen and why.

5.       Why in Table 2 for iodine in one case the value is given <0.62, in the other - <1.7. Has the detection limit of the methods been estimated?

6.       What is the reason for the extremely high chlorine value in sample JGB-1 (Table 3)? Maybe it is possible to repeat this measurement?

7.       Check lines 176-181. “Spectral interferences” - “no possibility of spectral interferences” - “can be explained by spectral interferences”. There is or no spectral interferences?

8.       Conclusion at line 189-190 is valuable, you can repeat it at the end of the article.

9.       Line 193 change chlorine to Cl.

10.   Section 3.2.1 is strange. Please avoid explanation of poor results by heterogeneous or homogeneous distribution, it is not obvious. (+line 241)

11.   Line 289-290 – move to section «Materials».

Author Response

We highly appreciate thorough and constructive comments. Let us describe here how we responded to them one by one. The revised portions are shown in red in the revised manuscript.

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

The authors have considered all reviewer comments and suggestions for improvement in  the revised manuscript. It is now recommended for publication.

However, there is still a  problem with units in Figs. 1 – 4. It should be µg g^-1, not ꝏ g^-1. Fig. 1 also does not contain any shaded area. Maybe it is a problem of the conversion of their original file into the pdf file available for the reviewer. Therefore, the authors should carefully check in the article proof, whether it is typeset correctly.