A New Approach to Enhancing Radiation Hardness in Advanced Nuclear Radiation Detectors Subjected to Fast Neutrons

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

This is an interesting paper about Low-Gain Avalanche Diodes (LGADs). The paper describes their use in high energy physics, the motivation to produce radiation hard LGADs and recent work to characterise them. Section 1 present the use of LGADs and the need to have them radiation hard. Section 2 give a more detailed description of what LGADs are. Section 3 presents their neutron irradiation. Section 4 explain how LGADs' performances are characterised. Section 5 focusses on the carbon-doped LGADs. Section 6 contains the main results of this paper: the behaviour of LGADs after irradiation. The paper is completed by conclusions in section 7.

This paper is very detailed and very pedagogical, more like a book chapter rather than an article (and it is referred to as a book chapter on line 72).

It is of good quality and to this referee, only minor corrections are needed.

The paper refers several time to LGADs as been fast devices without given any value for "fast". It would be useful to indicate what is the typical response time of LGADs and give a quicjk physical argument to confirm that carbon doping will not affect this fast response time.

Figue 2 looks very similar to an image that can be found on the internet. an the author confirm that they are the authors and copyright owners of all the figures? Otherwise the original author or the original source should be quoted.

Table 1 needs to be reworked to make appear the dose rate and energy explicitly for each sample  (or explain why it s not given).

- lines 127-132 and lines 311-316 give almost similar information.

Figure 13 and 14 should use the same colour code.

The authors of ref [4] need to be checked.

 

 

Typos:

- l125: figure caption on a new page

- l167: number with unit on a new line

- typo on l258

- typo on l319

 

Author Response

Dear Reviewer,

Thank you for your great comments. We have implemented your amendments as follows.

 

Comment no. 1: The paper refers several times to LGADs as being fast devices without giving any value for "fast." It would be useful to indicate what the typical response time of LGADs is and provide a quick physical argument to confirm that carbon doping will not affect this fast response time.

 

Our Answer: We thank the reviewer for this valuable comment. In the revised manuscript, we have clarified that the response time of LGADs is approximately 1–2 ns, with electrons and holes drifting in ~500 ps and ~700 ps, respectively, in the thin active layer (~50 µm) under saturated drift velocities [line 36]. Additionally, we have provided a physical argument to confirm that carbon doping does not affect this fast response time. Carbon enhances radiation hardness by trapping silicon interstitials, stabilizing the gain layer without altering the electric field configuration or carrier drift velocities, ensuring the response time remains unaffected. These clarifications have been added to Section [line 58].

 

Comment No. 2: Figue 2 looks very similar to an image that can be found on the internet. an the author confirm that they are the authors and copyright owners of all the figures? Otherwise the original author or the original source should be quoted.

Our Answer: We thank the reviewer for bringing this to our attention. Figure 2 was used in collaboration with Brookhaven National Laboratory (BNL) during our work with them before, and has also been included in a PhD thesis. To provide proper attribution, I have now cited the relevant BNL website (Ref. 23) in the revised manuscript. These references clarify the origin and collaborative nature of the figure. Let us know if you need any additional adjustments!

 

Comment No. 3: Table 1 needs to be reworked to make appear the dose rate and energy explicitly for each sample  (or explain why it s not given).

Our Answer: We thank the reviewer for their comment. In the revised manuscript, we have reworked Table 1 to explicitly clarify the dose rate, energy, and species for each sample. The dose rate corresponds to the implanted fluence value (e.g., 3×10^12, 3×10^13, 9×10^12) for each implantation, as now explicitly shown in the table. Additionally, the table includes tilt angles and detailed descriptions of each implantation step to enhance clarity. Let me know if further adjustments are required!

 

Comment No. 4: - lines 127-132 and lines 311-316 give almost similar information.

Our Answer: We have modified the section and removed the paragraph that we repeated for the second time instead, a short statement was added as highlighted. Thank you very much!

 

Comment No.5:  Figure 13 and 14 should use the same colour code. The authors of ref [4] need to be checked.

Our answer: Thank you so much! We have modified Fig. 14. The reference modified.

Typos were implemented.

Thank you so much for your valuable comments.

 

Best

Aref

Reviewer 2 Report

Comments and Suggestions for Authors

I think the work is very impactful, and the article is well-written and organized. I accept it in its present form.

Author Response

Dear Reviewer

 

I'm beyond grateful for your time and consideration!

 

My best

Aref

Reviewer 3 Report

Comments and Suggestions for Authors

The authors studies the effect of carbon-doping on the radiation hardness of LGAD detectors. The authors primarily used C-V voltammetry and SRP analysis to unravel the dependence of radiation hardness performance on carbon implantation amount. The amount of experimental data not only supports this research, but will also provide great reference for other works in the field. I recommended the publication of this manuscript. I just have a few minor suggestions:

Figure 6: create an inlet for the region where bias voltage is in [-12 V, -6 V], and capacitance is in [4e-10 F, 1e-9 F] to magnify the relative magnitudes of the different devices. Currently the traces are not resolved enough in that region to be distinguished.

Similarly for Figure 7 and 8, please make changes that could make it easier to distinguish traces. For Figure 7 I recommend expanding the Y axis scale, and for Figure 8 I recommend choosing more varieties of shapes for symbols of the traces, for example, circles, triangles and rectangles rather than only dots.

In Line 258 and Line 319, there is an extra “This” at the beginning.

Author Response

Dear Reviewer,

 

I'm beyond grateful for your comments:

first comment mainly realted to figures. Your point is really correct:

"

Figure 6: create an inlet for the region where bias voltage is in [-12 V, -6 V], and capacitance is in [4e-10 F, 1e-9 F] to magnify the relative magnitudes of the different devices. Currently the traces are not resolved enough in that region to be distinguished.

Similarly for Figure 7 and 8, please make changes that could make it easier to distinguish traces. For Figure 7 I recommend expanding the Y axis scale, and for Figure 8 I recommend choosing more varieties of shapes for symbols of the traces, for example, circles, triangles and rectangles rather than only dots."

 

Our answer:

We replotted with the main devices, and now everything is clear on C-V and the extracted doping profile. Previous pictures were not clear at all. You can find new images in Fig 7 and Fig 8. We removed Fig 8 (in first version) as it was not helpful! Others numberings have been updated accordingly. Please let us know your opinion.

 

Next comment:In Line 258 and Line 319, there is an extra “This” at the beginning.

We corrected these points. 

 

Thank you so much

Aref