Direct and Indirect Measurements of the ¹⁹F(p,α)¹⁶O Reaction at Astrophysical Energies Using the LHASA Detector and the Trojan Horse Method

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The manuscript of G.L. Guardo et al. deals with the measurement of the 19F(p,a)16O reaction cross section with two methods. Since this reaction has high astrophysical relevance, such a paper clearly deserves publication and Universe can be a suitable journal for it.

The manuscript seems to be scientifically sound, it does not contain any apparent flaws or errors, so I can accept it for publication. However, the authors should first consider my rather general comment given below.

My main concern with this paper is that it is not clear if it is a research article or a review. The manuscript header says „article” but in the text “review” is written and the paper indeed seems more like a review and not like an original research article. An original research article should provide new research results, which is not the case here. For the (p,a0) channel there are no new experimental data presented in the manuscript (the results shown were already published elsewhere) and for the (p,a_pi) channel the analysis is still in progress, so there are no results presented.

The authors should make it more clear what the purpose of this paper is. As an important reaction is discussed, a review would be perfectly fine and welcome. In such a case, however, a lot of (mainly technical) details, which were already published in previous papers, are not necessary. In this manuscript many things (including several figures) are just simply repeated from previous works. This should be avoided and the comprehensive discussion of the state of the art for this reaction should be put in focus. The astrophysical consequences (either available already, or to be reached with the upcoming data) also deserve more detailed description.

So, I suggest that the authors revise their manuscript to show more clearly the goal of this publication.

(One small further comment: In the abstract the production of calcium is mentioned, which is an element rather far away from fluorine. This is then not discussed at all in the paper. If something is important enough to be put in the abstract, then it should also be discussed in the text, in more detail.)

Author Response

We thank the referee for his/her time and effort in reviewing this manuscript. The referee points helped us to improve the quality of this work. We address each of the referee’s comments below.

My main concern with this paper is that it is not clear if it is a research article or a review. The manuscript header says „article” but in the text “review” is written and the paper indeed seems more like a review and not like an original research article. An original research article should provide new research results, which is not the case here. For the (p,a0) channel there are no new experimental data presented in the manuscript (the results shown were already published elsewhere) and for the (p,a_pi) channel the analysis is still in progress, so there are no results presented.

We thank the referee for the opportunity to clarify this aspect. Actually and most probably, we made a mistake during the submission phase selecting the wrong header. The purpose of the manuscript is clearly to give an overview of the status of the 19F results and experiments performed by the Asfin group. Indeed, as the referee correctly pointed out only already published results are present in the paper together with preliminary analysis of new experiments.

In such a case, however, a lot of (mainly technical) details, which were already published in previous papers, are not necessary. In this manuscript many things (including several figures) are just simply repeated from previous works. This should be avoided and the comprehensive discussion of the state of the art for this reaction should be put in focus. The astrophysical consequences (either available already, or to be reached with the upcoming data) also deserve more detailed description.

We agree with the referee and indeed we modified the manuscript accordingly. Now, the paragraphs related to the THM analysis (3.1.2 and 3.1.3) are compressed in only one and the text is reduced. Moreover, we also removed some not essentially figures (since they can be found in the cited papers)

One small further comment: In the abstract the production of calcium is mentioned, which is an element rather far away from fluorine. This is then not discussed at all in the paper. If something is important enough to be put in the abstract, then it should also be discussed in the text, in more detail

Taking into account the referee suggestion, we amended the manuscript as follow:
“Indeed, a breakout from the CNO cycles, characterized by the leakage from the CNO cycle to the NeNa cycle via the 19F(p, γ)20Ne reaction, is influenced not only by the abundance of 19F but also by the reaction rates of the 19F(p, γ)20Ne reaction and the competing 19F(p, α)16O reaction [17, 18]”

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

The manuscript presents an overview on the 19F(p,α_0,pi) 16O reaction measurements with direct and indrect approaches, some of which has been published while there is still ongoing efforts analyzing remaining α_pi channel. As the authors clearly stated, the measurement is very important for understanding of the F abundance puzzle and for  s-process nucleosynthesis in AGB stars. The manuscript is informative, well written and easy to follow. I fully recommend its publication i Univerise.

Some minor comments for the authors to consider:

The sentence that defines α_0,pi,gamma starting with "since the 19F(p,α) 16O reaction rate is the sum" reads really confusing. Some readers may not be able to link the α_0,pi,gamma symbol to represent the reactions to those three states.

In some cases, α_pi is not denoted with subscripts.

Fig 3 is really hard to read. And on the contrary to the caption, it is not really explained in the text. The only sentence related to it in page is a bit scattered and confusing.

There are a few other language problems like ", a good agreement is found between the 211 experimental data and the theoretical distribution is found."

 

 

 

 

 

Comments on the Quality of English Language

There are some minor issues spotted as partly mentioned above.

Author Response

We thank the referee for his/her time and effort in reviewing this manuscript. The referee points helped us to improve the quality of this work. We address each of the referee’s comments below.

The sentence that defines α_0,pi,gamma starting with "since the 19F(p,α) 16O reaction rate is the sum" reads really confusing. Some readers may not be able to link the α_0,pi,gamma symbol to represent the reactions to those three states.

We agree with the referee and indeed we modified the manuscript accordingly changing the sentence as follows:
“In particular, the $^{19}$F(p,$\alpha$)$^{16}$O reaction rate is the sum the rates related to the three open channels, namely (p,$\alpha_0$), (p,$\alpha_{\pi}$) and (p,$\alpha_{\gamma}$), where the $^{16}$O is left in its ground state, first excited state (6049.4 keV, 0$^+$) and second excited state (6129.89 keV, 3$^-$) respectively.”

 

In some cases, α_pi is not denoted with subscripts.

We thank the referee for his/her careful reading, and we checked the text to verify that the a_pi was denoted correctly.

 

Fig 3 is really hard to read. And on the contrary to the caption, it is not really explained in the text. The only sentence related to it in page is a bit scattered and confusing.

Taking into account the referee suggestion, we amended the manuscript as follow:
“The result shows excellent agreement and demonstrates the quality of the calibrations, as reported in fig. 3 where the black dots represent the simulated points superimposed on the experimental data at 18.5 MeV.”

 

There are a few other language problems like ", a good agreement is found between the 211 experimental data and the theoretical distribution is found."

We carefully re-check the text in order to solve these minor typos.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

As I wrote in my first report, the manuscript „seems to be scientifically sound, it does not contain any apparent flaws or errors”. The authors have addressed my only serious concern about the paper and made some modifications to the manuscript. So, I can accept now this version for publication in Universe. The paper header still says „article”. If it is possible, it should be changed to „review” in order to reflect the nature of this publication.