Probing the Elastic Scattering Differential Cross Section for Al + p at Backward Angles in a Low Energy Regime
, Karla Gutierrez Zayas-Bazán 2, Patricia G. Zayas-Bazán 3, Arcadio Huerta 4, Jorge Sastré-Hernández 5, Daniel José MarÃn-Lámbarri 4, Luis Acosta 4, Eduardo Andrade 4, Corina SolÃs 4 and Efrain R. Chávez Lomelà 4Round 1
Reviewer 1 Report
The authors presented joint experimental and theoretical study of proton elastic scattering on aluminium at backward scattering angles from 135 to 165 with the step of 5 degrees. For the experiment they used 1MVtandem accelerator facility of the Accelerator Mass Spectrometry Laboratory (LEMA) located at the Physics Institute of the National Autonomous University of Mexico. The proton beam energies were varied by 50 keV steps in the range from 800 keV to 2.1 MeV. The main experimental observable is the differential cross section for Al that was put on the absolute scale in units of Mb/sr by normalization to the absolute Rutherford scattering on gold. Beside experimental studies, the calculations have been performed with FRESCO software. The optical model calculations by both Woods-Saxon and São Paulo (SPP) optical potentials were done in order to compare with experimental points. The first used potential showed good agreement with experiments while the second one is poorer. What is very important is that all experimental data will be uploaded into IEAD database IBANDL.
Experimental set-up is briefly presented and refereed to the previous paper by the authors where it had been summarized in detail. Such kind of data of backscattering technique is an important tool in materials analysis especially on studies of light targets. From data presented in Figure 3 it is evident that elastic scattering on Alis dominated by resonances, which, as stated by authors and referenced in literature, result from nuclear potential scattering in addition to the Coulomb interaction. I have to agree with the authors that further experimental studies and calculations with higher precision are needed in future.
It seems to me that the quality of the paper will be improved if more details is going to be provided about Figure 2, how the ratio of number density of Au and Al atoms were obtained. Also, I would recommend to plot data from Table 1 regardless data presentation in figures 2 and 4 are very illustrative and made of high quality.
Author Response
For research article
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Response to Reviewer 1 Comments
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1. Summary |
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Thank you very much for taking the time to review this manuscript. We appreciate the time and effort that you have dedicated to providing your valuable feedback on my manuscript. We have been able to incorporate changes to reflect most of the suggestions provided by the reviewers. Please find the detailed responses below and the corresponding corrections highlighted/in track changes in the re-submitted files.
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2. Questions for General Evaluation |
Reviewer’s Evaluation |
Response and Revisions |
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Does the introduction provide sufficient background and include all relevant references? |
Yes |
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Are all the cited references relevant to the research? |
Yes |
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Is the research design appropriate? |
Yes |
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Are the methods adequately described? |
Yes |
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Are the results clearly presented? |
Yes |
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Are the conclusions supported by the results? |
Yes |
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3. Point-by-point response to Comments and Suggestions for Authors
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Comments 1: It seems to me that the quality of the paper will be improved if more details is going to be provided about Figure 2, how the ratio of number density of Au and Al atoms were obtained. Also, I would recommend to plot data from Table 1 regardless data presentation in figures 2 and 4 are very illustrative and made of high quality.
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Response 1: Indeed, this will improve our paper. In the revised version, we describe the way in which we calculate the ratio Nau/Nal (showing target stability during the experiment) [line 146-159]. Regarding to the Table 1, you raised an important point. However, plotting all data maybe hard to understand. That is the reason why we plotted only a set of selected data in figures 3 and figure 4. On the other hand, we noticed as well as the second reviewer, that we must include the errors associated with each differential cross section values into the Table 1. [So, we include the errors in Table 1]
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4. Additional clarifications |
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Assistant Editor pointed out that our article had a total of 2398 words, and kindly asked us to extend the text to 4000 words appropriately. In so doing, numerous changes were added to the text (all highlighted). The added text is in accordance with the suggestions made by the reviewers. Once again thank you for your time and dedication to review the article. |
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Author Response File: 
Author Response.pdf
Reviewer 2 Report
The paper reports on new measurements of the backward elastic cross section for the AL+p reaction at low energy.
The paper is generally well written and the data are of interest for the community, so my suggestion is to publish the paper, after some improvement.
1) As previous measurements of the same kind exist, the motivation for re-measuring namely this reaction in these conditions should be stressed already in the Introduction
2) the acronymes as 'PIPS detector', should be made explicit.
3) In Table 1 the differential cross sections should be reported together with their errors.
4) In general, in Figures and tables, the values should be reported with their errors, for example in Figure 3, to allow to judge of the level of the discrepancies among the different sets of data. If the errors are too small to be seen, this should be written explicitly. What is the red dashed line in Figure 3? It should be described in the caption.
5) The SPP optical potential does not fit the data for the given reasons. Are there efforts to improve/modify ? Does it help if one changes parameters?
6) The lines 126-128 are repeated in 133-135. They should be kept only in Conclusions.
some misprints
Line 55: 'The detectors energy' should be 'The detector energy'
Line 81 and in the caption of Fig. 2: '0.1242+-0.0021' should be '0.124+-0.002'
Line 85: 'normalized to Rutherford' should be 'normalized to the Rutherford cross section'
Line 88: 'calculations details. Also our data is compared' should be
'the calculation details. Also, our data are compared'
Line 92: 'was extracted' should be 'were extracted'
Line 137: 'provided, We' should be 'provided, we'
Some notes are above. in particularly one has to choose everywhere : 'data is' or 'data are'
Author Response
For research article
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Response to Reviewer 2 Comments
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1. Summary |
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Thank you very much for taking the time to review this manuscript. We appreciate the time and effort that you have dedicated to providing your valuable feedback on my manuscript. We have been able to incorporate changes to reflect most of the suggestions provided by the reviewers. Please find the detailed responses below and the corresponding corrections highlighted/in track changes in the re-submitted files.
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2. Questions for General Evaluation |
Reviewer’s Evaluation |
Response and Revisions |
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Does the introduction provide sufficient background and include all relevant references? |
Must be improved |
We thank you for your comment and take advantage to include additional background details and references to previous studies on this topic in [line 25-48]. Also, some comments about the optical potential studies were given in line [62-71]. |
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Are all the cited references relevant to the research? |
Yes |
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Is the research design appropriate? |
Yes |
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Are the methods adequately described? |
Can be improved |
We added more details that we hope will complete the description of the experimental methods used: i) a description of the isotope separator in [line 81-86]. Ii) a brief description of the acquisition system used [line 105-122]. Iii) the calculate the ratio Nau/Nal (showing target stability during the experiment) [line 146-159].
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Are the results clearly presented? |
Can be improved |
Thank you again. We included statistical errors in Table 1 and changed the symbols for Nelson y Rauhala data in figure 3 from ‘x’ to ‘o’, which greatly improved the visualization. |
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Are the conclusions supported by the results?
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Yes |
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3. Point-by-point response to Comments and Suggestions for Authors
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Comments 1: As previous measurements of the same kind exist, the motivation for re-measuring namely this reaction in these conditions should be stressed already in the Introduction. |
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Response 1: This system has been studied previously. However, each publication offers data that is not consistent with each other. Besides, there has been no previous effort to extract a nucleus-nucleus optical potential that describes well the data in the energy region of our interest. Our new measurements, show the need for even more detailed data to solve the inconsistencies between different authors. In addition, it provides a first attempt to extract the appropriate form factors for the nucleus-nucleus potential to be used in optical model calculations. [Information about it was added to the Introduction. line 55-61]
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Comments 2: The acronymes as 'PIPS detector', should be made explicit. |
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Response 2: Agree. The explicit “Passivated Implanted Planar Silicon (PIPS) detector” was added to the text. [line 89]
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Comments 3: In Table 1 the differential cross sections should be reported together with their errors. |
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Response 3: Agree. We have, accordingly, modified Table 1 to emphasize this point. The values of the errors of the differential cross section were added. Also, the expression dσ/dΩ was eliminated so that the contents of the table would fit in full. [Table 1 was modified]
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Comments 4: In general, in Figures and tables, the values should be reported with their errors, for example in Figure 3, to allow to judge of the level of the discrepancies among the different sets of data. If the errors are too small to be seen, this should be written explicitly. What is the red dashed line in Figure 3? It should be described in the caption. |
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Response 4: When applicable, a sentence was added to the text explicitly stating that the errors are too small to be seen in the graph. [The meaning of the red dashed line was added to the caption of the Figure 3].
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Comments 5: The SPP optical potential does not fit the data for the given reasons. Are there efforts to improve/modify? Does it help if one changes parameters? |
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Response 5: The SPP optical potential, as stated in the manuscript, is designed to study Heavy-ion collisions. We were unable to find a good fit with the information we have presently. However, since we plan to extend our measurements with heavier projectiles, we might have, in the future, enough data to help us find a global prescription to produce the appropriate ion-ion potentials.
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Comments 6: The lines 126-128 are repeated in 133-135. They should be kept only in Conclusions. |
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Response 6: Agree. The lines 126-128 were eliminated.
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4. Response to Comments on the Quality of English Language
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Point 1: Line 55: 'The detectors energy’ should be 'The detector energy' Response 1: Done!
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Point 2: Line 81 and in the caption of Fig. 2: '0.1242+-0.0021' should be '0.124+-0.002’ Response 2: Done!
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Point 3: Line 85: 'normalized to Rutherford' should be 'normalized to the Rutherford cross section' |
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Response 3: Done!
Point 4: Line 88: 'calculations details. Also our data is compared' should be 'the calculation details. Also, our data are compared' Response 4: Done!
Point 5: Line 92: 'was extracted' should be 'were extracted' Response 5: Done!
Point 6: Line 137: 'provided, We' should be 'provided, we' Response 6: Done!
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5. Additional clarifications |
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Assistant Editor pointed out that our article had a total of 2398 words, and kindly asked us to extend the text to 4000 words appropriately. In so doing, numerous changes were added to the text (all highlighted). The added text is in accordance with the suggestions made by the reviewers. Once again thank you for your time and dedication to review the article. |
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