# Improving reproducibility in geochronology: application in gamma spectrometry

Lebrun Brice, Nicolas Frerebeau

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Lebrun Brice, Nicolas Frerebeau. Improving reproducibility in geochronology: application in gamma spectrometry. 16th International Luminescence and Electron Spin Resonance Dating conference (LED2021), Sep 2021, Burgos, Spain. . [hal-03330865](https://hal.science/hal-03330865)

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Brice Lebrun<fnref n="1" />, Nicolas Frerebeau<fnref n="1" />

# Improving reproducibility in geochronology: application in gamma spectrometry.

52%

is the percentage of researchers who consider that we are experiencing a **reproducibility crisis**, according to a study published in Nature (1576 respondents) [1, 2, 3].

Overcoming this crisis requires a deep change in our practices of publication and diffusion of research tools and data. Reproducible research requires a shift from proprietary software to open source software whose source code can be accessed, reviewed and modified if needed.

## Gamma spectrometry

Gamma-ray spectrometry is an essential tool for paleodosimetric dating method such as OSL. It allows the determination of radioelement content for the calculation of the **dose rate** (uranium, thorium and potassium). It is also a valuable tool for studying possible imbalances in the uranium series.

In-situ gamma spectrometry allows the estimation of gamma dose rates directly in the field, which is especially useful for complexed dosimetric environments with **dose rate heterogeneities**.

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<figure><img src="image_4.png" /><figcaption>Gamma spectrometer in use at IRAMAT-CRP2A; right: broad energy and low background Germanium; left: Canberra InSpector1000.</figcaption></figure>

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## A challenging context

The processing of gamma-ray spectra requires a large number of steps (correction of energy shift, detection of peaks, corrections related to physical phenomena, etc.). This is generally done using proprietary software such as genie2000®, which is only available under Windows®.

In-house solutions are implemented, such as Visual Basic Advance® macros in Microsoft Excel®. This workflow raises two challenges.

> « So far, there is no easy-to-use solution to carry out these steps. »

**Lack of transparency:** details of the spectrum processing are not presented in publications and in-house solutions are not made available to the community. This severely limits the reproducibility and reliability of the measurements; see [4] for a broader discussion in the field of luminescence dating.

**Access problem:** the use of proprietary, commercial software is a limiting factor for community members, which restricts collaborations and future developments.

## The gamma package: an integrated solution for the analysis of gamma-ray spectrometry data, from raw spectrum processing to K, U and Th content and dose rate estimation.

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CR

Gamma is written in R. R has many advantages, such as being easy to learn and use. It is available on platforms and its community offers efficient support. **R is free and open source**, which guarantees transparency and modularity [6].

## Work in progress

This work enhances a previous work allowing field gamma spectrometry spectra processing [5]. All these functionalities will be released by the end of 2021. Learn more at crp2a.github.io/gamma

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## Join us!

Source code and installation instructions are available online. Users are invited to contribute, share feedback, request new features or report bugs on GitHub.

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read the
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Lebrun et al., 2020

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Université
BORDEAUX
MONTAIGNE

<footnote>[1] **Baker**, M. (2016). 1,500 scientists lift the lid on reproducibility. Nature, 533(7604):452–454.</footnote>

<footnote>[2] **Ioannidis**, J. P. A. (2005). Why Most Published Research Findings Are False. PLOS Medicine, 2(8):e124.</footnote>

<footnote>[3] **Pashler** H., Wagenmakers E. (2012). Editors' Introduction to the Special Section on Replicability in Psychological Science: A Crisis of Confidence? Perspectives on Psychological Science, 7(6):528–530.</footnote>

<footnote>[4] **Kreutzer**, S., Burow, C., Dietze, M., Fuchs, M. C., Fischer, M., and Schmidt, C. Software in the Context of Luminescence Dating: Status, Concepts and Suggestions exemplified by the R Package 'Luminescence'. Ancient TL, 35(2): 1–11, 2017.</footnote>

<footnote>[5] **Lebrun**, B., Frerebeau, N., Paradol, C., Guérin, G., Mercier, N., Tribole, C., Lahaye, C., Rizza, M. (2020). gamma: An R Package for Dose Rate Estimation</footnote>

<footnote>from In-Situ Gamma-Ray Spectrometry Measurements. Ancient TL, In press.</footnote>

<footnote>[6] **R Core Team**.R: A Language and Environment for Statistical Computing. R Foundation for Statistical Computing, Vienna, Austria, 2020</footnote>

<footnote>Drawings modified from macrovector and rawpixel.com via freepik.com</footnote>

<footnote n="1">¹ IRAMAT-CRP2A (UMR 5060 - CNRS, Université Bordeaux Montaigne)</footnote>

<footnote>Maison de l'archéologie, Université Bordeaux Montaigne</footnote>

<footnote n="33607">33607 Pessac CEDEX France</footnote>