Towards Construction of a Novel Nanometer-Resolution MeV-STEM for Imaging Thick Frozen Biological Samples

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The authors of the manuscript have proposed design of new STEM. It investigation of frozen biological samples, the thickness of which is much greater than the similar value attainable for TEM (300-500 nm). The authors have outlined the major challenges as generation of nano-sized electron beam with low emittance and energy spread, low electron dose delivered to the sample and accuracy of beam probe scanning of half beam size at the specimen. The most attention has been drawn to elaboration of MeV class electron source, design of STEM column and electron beam scanning system capable of achieving a nanometer precision at the specimen.

The quality of the provided preliminary simulation studies, hardware researches and development is of a very high scientific level. The narrative is logical, the description of the work is very detailed. There are no doubts that the present work deserves to be published in Photonics.

Author Response

Response to Reviewer 1 Comments

1. Summary: We appreciated the reviewer spending valuable time in reviewing our paper and being positive on the scientific motivation and preliminary design result of the MeV-STEM instrument.
2. Questions for General Evaluation:                                                               Are the results clearly presented? Can be improved.                                  For a few important issues, we made them much clearer. E.g., We improved the description of the difference between STEM and TEM in Lines 105-109; we removed some misleading words "dynamic process" and "in-situ" in Lines 53 to 55 since Cryo-ET can resolve subcellular structures, however, for studying dynamic processes, it can only indirectly provide the information, which assists the study of dynamic processes; we added a sentence in line 360 to explain the reason why we choose the electron beam being operated in the pulse mode as the following: “…The choice of the pulse mode is mainly due to its compatibility with the L-band SRF Linac, which is applied to boost the electron energy up to a few MeV with RF frequency of 1.3 GHz (see detailed explanation in Section 2.3.2).”.
3. Point-by-point response to Comments and Suggestions for Authors:            NA.

Reviewer 2 Report

Comments and Suggestions for Authors

review attached

Comments for author File: Comments.pdf

Author Response

Response to Reviewer 2 Comments

1. Summary: We appreciated the reviewer spending valuable time in reviewing our paper and giving critically important comments and suggestions on our manuscript. We made those changes, which greatly improved the quality and readability of the manuscript.
2. Questions for General Evaluation:  NA                                                            
3. Point-by-point response to Comments and Suggestions for Authors:          We addressed point-by-point response in the attached file.

Author Response File: Author Response.docx