Technical note: On the reliability of laboratory beta-source calibration for luminescence dating

Mauz, Barbara; Martin, Loïc; Discher, Michael; Tribolo, Chantal; Kreutzer, Sebastian; Bahl, Chiara; Lang, Andreas; Mercier, Nobert

doi:https://doi.org/10.5194/gchron-3-371-2021

Articles | Volume 3, issue 1

https://doi.org/10.5194/gchron-3-371-2021

© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

https://doi.org/10.5194/gchron-3-371-2021

© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 3, issue 1

Short communication/technical note

|

23 Jun 2021

Short communication/technical note |

| 23 Jun 2021

Technical note: On the reliability of laboratory beta-source calibration for luminescence dating

Barbara Mauz, Loïc Martin, Michael Discher, Chantal Tribolo, Sebastian Kreutzer, Chiara Bahl, Andreas Lang, and Nobert Mercier

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Final revised paper (published on 23 Jun 2021)
Supplement to the final revised paper
Preprint (discussion started on 25 Nov 2020)
Supplement to the preprint

Interactive discussion

Status: closed

AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment

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RC1: 'Comments on the manuscript GChron-2020-36 by Mauz et al.', Anonymous Referee #1, 16 Dec 2020
- AC1: 'Your review', Barbara Mauz, 21 Dec 2020
- AC2: 'Reply on RC1', Barbara Mauz, 04 Feb 2021
RC2: 'Review of: Technical note: On the reliability of laboratory beta-source calibration for luminescence dating', Anonymous Referee #2, 07 Jan 2021
- AC3: 'Reply on RC2', Barbara Mauz, 04 Feb 2021

Peer-review completion

AR: Author's response | RR: Referee report | ED: Editor decision

ED: Publish subject to revisions (further review by editor and referees) (18 Feb 2021) by Julie Durcan

AR by Barbara Mauz on behalf of the Authors (12 Mar 2021) Author's response Author's tracked changes Manuscript

ED: Referee Nomination & Report Request started (23 Mar 2021) by Julie Durcan

RR by Anonymous Referee #1 (05 Apr 2021)

Suggestions for revision or reasons for rejection

Comments on the revised version of Mauz et al. (GChron-2020-36)

Considering the comments on the previous version of this manuscript, the authors were able to improve the clarity of the text and eliminate most technical mistakes. I recommend publication of this technical note, after the following points have been addressed by the authors.

l. 70: Please add here that the pre-selection of mini-sources occurs only for sources in the lexsyg research readers. The information that smart readers do not contain pre-selected sources appears only later in the text.

l. 75f.: It should read “source–sample distance”. Additionally, for which grain size is this distance valid?

Table 2, last row: I guess the aliquot diameter should be 7.95 mm, not 8 mm.

l. 122: I still think the units here should be µm instead of mm.

Table 3: For sample R108_4: aliquot size should be 7.95 mm.

Table 4: Why are you referring here to the sample code in Table 1 in the caption? The samples codes are given in column 1 of this table as well. Second column: not necessary to give the unit µm, since the shown parameter is a ratio. Aliquot size should be 7.95 mm, not 8 mm.

l. 181: The text describes a maximum difference of 26% between dose rates derived from various aliquot and grain sizes, but this value is not reflected by the ratio values shown in Table 4 (maximum variation of 21% in row 6 for 1 mm aliquots).

Fig. 3: Please indicate in the caption, which samples are referred to when normalizing the data for 5 mm and 7.95 mm aliquots. From the plots, it is clear that it is sample F14-90 closed ring, but it is less clear for the 7.95 mm data.

l. 192: Again, I cannot see the 26% difference from the tables or Fig. 3. Please carefully cross-check.

l. 194f.: The same seems to be true not only for the planar source, but also for the closed ring source (see Fig. 4).

l. 195: The increase in dose rate should be about 7%, according to Fig. 4.

l. 207: Should read “Armitage and Bailey, 2005”).

Fig. 6: I noticed that the plotting symbols are covering the error bars in (A), while the error bars are on top of the plotting symbols in (B). It would be good to homogenize the plot style for both subplots, i.e., to add the errors bars in (A) in the same way as in (B). Please also adjust the y-axis labelling (“Dose Rate” vs. “Dose rate”).

l. 222: Please indicate that this sentence refers to experimental data. Considering the previous sentence, this is not very clear.

Caption to Fig. 7: In the last sentence please write: “Dose rate is normalised to a depth of 10
μm and …”

Supplement

Backscatter. Check the last sentence in this paragraph for consistency.

Details of the MCNP6.2 simulation results. You write: “For each simulation run aliquot size
and/or diameter of the cylindrical target (with a defined thickness and diameter made of SiO2) was changed while everything else (e.g., irradiation geometry, number of initial particles) was kept constant.” It is not clear to me here what the difference between aliquot size and the diameter of the cylindrical target is. Please clarify shortly.

The arrangement of plotting panels on pages 3-5 of the supplementals is optically not very pleasing, but I leave this to the authors if they wish to fix that.

In general: Please be consistent in the spelling of the word dose rate (“dose rate” vs. “dose-rate”).

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RR by Anonymous Referee #2 (15 Apr 2021)

Suggestions for revision or reasons for rejection

I wish to thank the authors for their detailed consideration of my comments and those of my fellow reviewer. The result is a clearer and more informative manuscript which, subject to some minor corrections, is very suitable for publication in Geochronology. The paper represents an important contribution to the literature on beta-source calibration, and proposes some interesting avenues for future research.

Minor corrections:
Line 80, Table 3 last row, Table 4 titles: Still refer to 8 mm aliquots as opposed to 7.95 mm.
Line 121: layer depths in microns not mm.
Table 4, planar source, 1 mm aliquot, F19-90: Normalised dose rate should be ~110.4 % not ~114%
Table 4, closed ring, 180-250 µm sample: Should be R113_180 not R17_180 I think.
Lines 189-195: It would be really helpful to the reader if each statement made reference to the relevant table and/or figure since this paragraph draws information from a large number of sources.
Line 191: For clarity consider starting the sentence "In contrast, for aliquot sizes <7.95 mm, the difference..."
Line 193: For large coarse grains Table 3 suggests that there is a (statistically insignificant) increase in dose rate with decreasing aliquot size for both the planar and closed ring source rather than a decrease as you suggest.
Line 194: With the correction to Figure 4 suggested below, it is the closed ring source that shows the largest increase in dose rate between 1 and 7.95 mm aliquots.
Figure 4: As with Fig.3, the F14_90 data are normalised to that for 5 mm aliquots not 7.95 mm as indicated in the caption.
Figure 4: The data point for F14_90 should be at ~1.04 rather than 1.08 following the correction to Table 4 noted above (I think you used the incorrectly calculated normalised % to plot Fig. 4).
Line 204 and 282: We may be talking past each other here, but I don't think that "jump" is the correct word to describe the pattern of data presented by Armitage and Bailey (the latter misspelled on line 207). In my view the point at ~55 µm represents the continuation of a trend of gradually increasing dose rate established by data from the three smallest grain sizes. As such, ~55 µm is the point above which dose rate no longer increases with grain size rather than a "jump" between lower dose rates at smaller grain sizes, and higher dose rates at larger sizes. Maybe say that the modelled data show a more progressive change in dose rate with grain size than do Armitage and Bailey's experimental data?
Line 254: By "the thicker the aliquot" I presume you mean "the larger the grain size". If so, I think the latter formulation is clearer.
Line 287: The Spooner and Allsop reference needs a year.

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ED: Publish subject to technical corrections (17 Apr 2021) by Julie Durcan

ED: Publish subject to technical corrections (20 Apr 2021) by Georgina King (Editor)

AR by Barbara Mauz on behalf of the Authors (10 May 2021) Author's response Manuscript

Post-review adjustments

AA: Author's adjustment | EA: Editor approval

AA by Barbara Mauz on behalf of the Authors (22 Jun 2021) Author's adjustment Manuscript

EA: Adjustments approved (22 Jun 2021) by Julie Durcan

Short summary

Luminescence dating requires irradiating the sample in the laboratory. Here, we address some concerns about the reliability of the calibration procedure that have been published recently. We found that the interplay between geometrical parameters such as grain size and aliquot size impacts the calibration value more than previously thought. The results of our study are robust and allow us to recommend an improved calibration procedure in order to enhance the reliability of the calibration value.