URANOS v1.0 – the Ultra Rapid Adaptable Neutron-Only Simulation for Environmental Research

Köhli, Markus; Schrön, Martin; Zacharias, Steffen; Schmidt, Ulrich

doi:https://doi.org/10.5194/gmd-16-449-2023

Articles | Volume 16, issue 2

https://doi.org/10.5194/gmd-16-449-2023

© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

https://doi.org/10.5194/gmd-16-449-2023

© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

Articles | Volume 16, issue 2

Model description paper

|

23 Jan 2023

Model description paper |

| 23 Jan 2023

URANOS v1.0 – the Ultra Rapid Adaptable Neutron-Only Simulation for Environmental Research

Markus Köhli, Martin Schrön, Steffen Zacharias, and Ulrich Schmidt

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Final revised paper (published on 23 Jan 2023)
Preprint (discussion started on 07 Jun 2022)

Interactive discussion

Status: closed

RC1:
'Comment on gmd-2022-93', Anonymous Referee #1, 01 Aug 2022

The authors present an excellent overview of the URANOS code in great detail. Given the continued use of CRNS this streamlined neutron transport code will be of great use to the community for evaluating and designing future experiments. The paper is well written and acceptable following some minor revisions. My only moderate comment is the need for more complex field data for validating the results (say irrigated row crops). These data would be greatly supported by URANOS model simulations to help untangle the complexity of this system. There have now been a number of papers developing this code (L600-620). Please see below for a few minor comments to address.

L58: Use of ontop is a bit awkward, please revise.

L126: is l the path length, please define here as well as sigma.

L252. "in a converter takes place". I don't follow this statement please revise.

L440. A space is needed between the words to start sentence.

L498: Replace "As far as" with "If".

L520: Figure 11 is discussed before figure 10.

L522: Neutron paths not neutrons paths

L585: For more than 50 years ...

L604: fine tune.

L600-620: I think a table summarizing the various studies with URANOS would be easier to read and reference for the reader. Please consider changing.

L627. I don't follow this sentence about the evaluation of cross sections. Think there may be a missing word somewhere?

Citation: https://doi.org/10.5194/gmd-2022-93-RC1
- AC3: 'Reply on RC1', Markus Köhli, 28 Oct 2022
  
  Dear Editor, dear Reviewer 1,
  please find attached our response to your comments.
  The diff is available here: https://www.physi.uni-heidelberg.de/Forschung/ANP/Cascade/URANOS/Files/URANOS_paper_Diff_Revision.pdf
  
  Citation: https://doi.org/10.5194/gmd-2022-93-AC3
RC2:
'Comment on gmd-2022-93', Anonymous Referee #2, 16 Sep 2022

This is a well developed manuscript, demonstrating the applicability of a novel though well-tested code. The manuscript is well readable, inspirational and easy to access for environmental scientists although containting dense information on physical processes and modelling. I recommend publication in GMD with minor revisions urging the authors to expand on a few minor points (see below) and add a new section on limitations and outlook. This section will benefit the readers and inspire the next generation of researchers to build on this code, increase the user space and the capabilities of CRNS to deliver accurate environmental observations.

Please adress following questions (in the new section):

What is the run time on a standard architecture (e.g. interl Core i5, 8GB RAM, Windows or Unix)?

Is the code parallelized for HPC applications?

What are the most expensive calculations and how to they scale from 2D to 3D for a "simple" geometric set up?

Can the atmosphere and cosmic ray interactions be modelled using URANOS code?

What is needed and what is the uncertainty to expand the code to include uncertainty from the cosmic ray energy spectrum at the top of the atmosphere and further particles?

Given URANOS is applied to simulate each CRNS locations, what are the remaining major uncertainties constraining the accuracy of cosmic ray neutron sensor derived hydrogen content in the CRNS footprint?

Line 132: It is unclear for the reader, how TRandom3 is programmed, language, and what a "modern architecture" is. Are the authors referring to HPC systems, GPU based HPCs or Laptops build in 2019? Please specify what you refer to as modern architecture ideally in the flops as measure for computational performance.

Line 133: Please also mention possible other random number generators and are they available? If those are not relevant questions, then it seems the technical details are not needed and I recommend to simply state that "the TRandom3 random number generator is used" and remove the technical details on random number generation from the manuscript in this paragraph 2.2.

Line 208: Please clarify what "MT numbers" are. Random "Mersenne Twister" numbers would not define reaction types, I assume.

Line 215: What is ensemble statistics?

Line 219: Please state which relevant and non-relevant interactions you are referring and what are the "two different types"?

Line 222: Please clarify, how is it possible that myons are not contributing while myons are the major cosmic rays entering the atmosphere, and neutrons are only a product of myon inter-action?

Line 325: Please state recommended default setting for the source.

Line 332: Please state recommended default starting angle.

Citation: https://doi.org/10.5194/gmd-2022-93-RC2
- AC4: 'Reply on RC2', Markus Köhli, 28 Oct 2022
  
  Dear Editor, dear Reviewer 2,
  please find attached our response to your comments.
  The diff is available here: https://www.physi.uni-heidelberg.de/Forschung/ANP/Cascade/URANOS/Files/URANOS_paper_Diff_Revision.pdf
  
  Citation: https://doi.org/10.5194/gmd-2022-93-AC4
AC1: 'Comment on gmd-2022-93', Markus Köhli, 28 Oct 2022

This review targets the first part of the manuscript, especially regarding the technical aspects. It is posted by the author due to the discussion section already being closed.
The publication shows an profound knowledge of the authors about the existing programs and the underlying physics and IT concepts. There are, however, some points that would improve the document:
* For people from other fields of research it is partly difficult to read, because the methods are not always described, e.g. half a sentence on how CRNS works would be helpful.
* Similarly, there are terms used that are not common to all fields. They should either be explained or alias names added, especially
* Is ‘evaporation’ of neutrons the same as ‘spallation’ of neutrons?
* Is ‘ray-casting’ the same as ‘ray-tracing’?

* Equation (1) to (4) are only consistent, if (3) and (4) calculate p(x) dp, not p(x) dx
* In Eq.(5), the second ξ should be replaced by anything else, e.g. ξ’. As it is written now, the equation is not correct.
* Surprisingly, it sounds like the authors have doubts about the Monte Carlo method.
* Some suggestion for text improvement:

* 47 – 49: can be omitted, as the programs are described in the following paragraphs
* Chapter 1.2: it could be added that the programs dedicated to neutron instrumentation and virtual neutron experiments (McStas, VITESS, RESTRAX, …) also allowed fast simulations by restricting its use to neutrons and ignoring nuclear reactions
* 106 – 112:: I cannot see the problem of the multigroup method
* 119: performance of GEANT4: what is missing, speed or accuracy or …?
* 156 – 15: I don’t understand that
* 214f: Why? What is done instead?
* 226: ‘Whereas’ -> ‘While’

* Style: often there are too few commas in too long sentences.
* Figure 1:

* I wonders if neutrons are generated in the source or the soil layer.
* An explanation of the particle symbols and a vertical scale would be good

* Figure 2:

* I think the ‘Layer stack’ is still a ‘Neutron stack’.
* Is there no flight direction stored?

Citation: https://doi.org/10.5194/gmd-2022-93-AC1
AC2: 'Comment on gmd-2022-93 (Reviewer No.3 Response)', Markus Köhli, 28 Oct 2022

Please see the attached file for the Review Response for Reviewer No. 3

Citation: https://doi.org/10.5194/gmd-2022-93-AC2

Peer review completion

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

AR by Markus Köhli on behalf of the Authors (01 Nov 2022) Author's response Author's tracked changes Manuscript

ED: Referee Nomination & Report Request started (08 Nov 2022) by Wolfgang Kurtz

RR by Anonymous Referee #1 (08 Nov 2022)

RR by Anonymous Referee #2 (09 Nov 2022)

ED: Publish subject to minor revisions (review by editor) (19 Nov 2022) by Wolfgang Kurtz

AR by Markus Köhli on behalf of the Authors (27 Nov 2022) Author's response Author's tracked changes Manuscript

ED: Publish subject to minor revisions (review by editor) (10 Dec 2022) by Wolfgang Kurtz

AR by Markus Köhli on behalf of the Authors (10 Dec 2022) Author's response Author's tracked changes Manuscript

ED: Publish subject to minor revisions (review by editor) (15 Dec 2022) by Wolfgang Kurtz

AR by Markus Köhli on behalf of the Authors (16 Dec 2022) Author's response Author's tracked changes Manuscript

ED: Publish as is (19 Dec 2022) by Wolfgang Kurtz

Short summary

In the last decades, Monte Carlo codes were often consulted to study neutrons near the surface. As an alternative for the growing community of CRNS, we developed URANOS. The main model features are tracking of particle histories from creation to detection, detector representations as layers or geometric shapes, a voxel-based geometry model, and material setup based on color codes in ASCII matrices or bitmap images. The entire software is developed in C++ and features a graphical user interface.