Development of a Radio-Frequency Quadrupole Accelerator for the HL-2A/2M Tokamak Diagnostic System

Round 1

Reviewer 1 Report

The authors present an important progress report on their development of a new Peking University and Southwestern Institute of Physics deuteron Radio Frequency Quadrupole accelerator and their further studies of the migration and deposition of impurities on the first wall of a tokamak facility. In the study some new results are presented but also some of data are repeated from their previous studies. The same authors have recently published their study on the same topic in other journal (their reference [19] 2022 JINST 17 P01030). There are rather big similarities in two papers: i) titles; ii) sentences in abstracts; iii) in the present manuscript Figs. 3 and 5 are identical to Figs. 1 and 2 in that previous reference, respectively; iv) the first 10 to 12 references are the same in both papers. Some notations should be corrected, for instance in Abstract H2+ should be replaced by 2H+ since the nucleon number (mass number) should be shown in the left superscript position.

Author Response

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Reviewer 2 Report

The authors present the basic design and commissioning results of the deuteron RFQ developed by Peking University and SWIP. The machine design is interesting even if it employs quite standard techniques and the commissioning results are appropriate for Tokamak diagnostic applications. I, therefore, believe that the manuscript is suited for publication in Applied Science. I just have a few comments I'd like the authors to address before publication, which are listed below:

• Please define LEBT on page 2 instead of page 11. Similarly, define S_11 in line 114
• Line 110. It is difficult to judge whether the 80% redundancy is an appropriate choice for the machine under discussion and the results presented in the manuscript. Can you provide motivations for this choice?
• 135 I was surprised by the fact that hydrogen degassing was found to be an issue after the commissioning. OFE copper is often annealed before ultra-high-vacuum (UHV) applications to mitigate hydrogen degassing. Why did you think (at the beginning, at least) that degassing would have been negligible? Was the copper by Chinalco Luoyang certified for UHV applications?
• I would replace Fig. 13 with a more readable figure (it is a scope screenshot)
• 219. The shunt resistance turned out to be 8% less than the simulated value. Do you know why?
• Equation (12). Please increase the size of “(“ and “)”
• Sec 4.3 Having a session of comparison with other RFQ is a good idea. However, I would have loved to have a discussion together with the comparison, in particular, about the power limitation of the RFQ employed here and possible limitations in its application scope.
• Table 2 “the RFQ” --> “this work”

Author Response

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Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

The manuscript has been improved. Just minor correction, in Fig.3 x-axis needs units.