GENERAL COMMENTS

The preprint by Kerber et al. presents an algorithm designed for handling raw data treatment, corrections, age calculation, and error estimation for ²³⁰Th/U dating using multi-collector inductively coupled plasma mass spectrometers (MC-ICP-MS). The algorithm is coded in Python and also provided as an open-source graphical user interface (GUI) software. A case study of a stalagmite from Larga Cave, Puerto Rico, is used to demonstrate how the algorithm works and its ability to calculate ages with uncertainties as low as 0.3-0.6%.

The intention of the algorithm is to simplify the data reduction and age calculation in a more reproducible and standardized manner. Discussion of data treatment includes corrections for various measurement artifacts such as peak tailing and hydride interference, and the importance of outlier correction. The preprint makes a case for the use of medians instead of means for more accurate data analysis. In addition, the preprint discusses the significance of initial ²³⁰Th correction and shows how easily the initial (²³⁰Th/²³²Th) activity ratio can be adjusted in the GUI to assess or accomplish Th correction.

Different detector arrangements used in different laboratories can already be accommodated in the GUI, but expert users can also modify the code if their detector arrangement is not supported.  Importantly, users of the ²³⁰Th/U dating technique who are not involved in the measurements and production of the data can easily become involved in the data treatment and age calculation. The GUI is well-designed with a workflow that is easier to follow, and the preprint adequately describes how to use the GUI and make changes to constants or assumptions. Data treatment and age calculations can be time-consuming and external users can wait a long time before receiving results of their submitted samples, but the GUI can assist many labs with relegating the data treatment and age calculation steps to the external users, and thereby expedite the finalization of results.

SPECIFIC COMMENTS

It is not explicitly stated that the GUI is for handling data from ThermoFisher Neptune instruments only or how data from other instruments can be handled. This would be beneficial to users of the ²³⁰Th/U dating method with data from other instruments.

TECHNICAL CORRECTIONS

Line 51: The use of "(i)" is confusing since no list is provided.

Line 62: “initial Thorium” should be “initial Th” for consistency within the same sentence and entire document.

Line 259: In this section “3.3 Analysis tab” the numbers in parentheses are not consistent with Figure 3. For example, line 265 makes reference to (3) for “Start Analysis” and (4) for presentation of the results, but there is no (3) and (4) in Figure 3.

Line 263: The exemplary Excel file for the weight table provided in the supplementary data should have its sheet names and column headers translated from Deutsche to English for accessibility.

Line 310: Delete the first “as well as the algorithms Stalage, copRa and bchron linear interpolation”

Line 316: Caption for supplementary Figure S3 has “223Th” instead of “232Th”

Line 353: “which is much stronger influenced by” please revise. Strongly instead?

Line 373: “this correction particularly” is missing “is”

This paper presents a Python-based program “U-Th Analysis” designed for U-Th isotopic data analysis for MC-ICPMS U-series dating. The program has a friendly graphical user interface and is open for the source code, which can be modified according to the measurement methods. This program comprises many automatic functions: e.g., to calculate U and Th tailing effects, identify outliers in isotopic ratios, correct for initial 230Th contamination, as well as to load and save data. I support to accept this paper for publication, as a transparent data treatment algorithms is desired for each of dating laboratories.

I have a few comments:

• U-Th isotopes can be measured using MC-ICPMS with different methods, and in many labs, the two elements were measured separately. In the Conclusion of this study, it was mentioned that the U-Th were measured simultaneously. I think the isotopic measurement method should be clarified before describing the program, probably in the section of “2.2. Chemical preparation and instrumentation”.
• If I understand well, the “Input” tab performs corrections of blank, tailing, and hydride, the “Inspect” tab filters the outliers from isotopic ratios, and the “Analysis” tab calculates the U-series age and corrects for initial 230Th contaminations. The combination of FC and SEM was used for U-Th measurements, so, I want to know how the SEM/FC yield is corrected, and how mass fractionation is corrected, and if the uncertainties of the two factors are considered in the program.
• In line 211, it was mentioned that the instrument background is measured between all sample and standard measurements for 70 s. Is the background measured on SEM by peak-jumping or by the combination of SEM and FC? For the blank correction, are the outliers in the blank measurements filtered.

A few typos:

• Line 30: The “manifold in geochemistry, archaeology, and climate science” was repeated.
• Line 192: What is the “GUI (10)”?
• Line 205: It should be “Thorium tailing”.
• Line 323; It should be “Figure 5”.