Radioargon (39Ar and 37Ar) and neutron underground production rate calculator

Developed by: Dr. Stephanie Musy and Dr. Roland Purtschert
Climate and Environmental Physics Institute, University of Bern

Described in: Musy S. and Purtschert R., 2023, Reviewing 39Ar and 37Ar underground production in shallow depths with implications for groundwater dating, submitted in Science of the Total Environment.

When using the calculator for your research, please cite the above reference.


The app can be accessed by following this LINK.



This web-app was developed with the Open Source software RStudio (R Studio Team, 2020) and the package Shiny (Chang et al., 2022).

The app consists of an input panel and multiple tables. In the input panel, the user can chose pre-defined rock composition from a list of typical formations [as compiled by Fabryka-Martin (1988)] or set up a custom rock composition.  In the latter case, the user will be asked to provide the elemental weight fractions [wt %] of the main components, the porosity φ [%], grain density ρr [g cm-3], as well as the neutron production rates from U/Th decay chains and spontaneous fission Pn,U/Th [atoms g-1 yr-1].  φ and ρr are used for the calculation of the rock bulk density ρ=φ⋅ ρw +  (1-φ) ⋅ ρr [g cm-3], which affects the attenuation of neutron fluxes with depths.

Neutron production rates:  Pn,U/Th  can be calculated with the Python script available under this LINK (Šrámek et al., 2017).

The three tabs “Neutrons”, “Argon-39” and “Argon-37” allow for the visualization of the production rate profiles with depths (in neutrons or atoms g rock-1 yr-1). A data file in XLSX format can also be downloaded under “Tables”.

The R-script and input files are available by contacting the authors. To run the App on a personal computer, open the file “app.R” in RStudio and press the “Run App” link in the top-right corner of the R Script section of the RStudio window.  The output files are created in the corresponding folder.