Proof-of-Principle of Absolute Dosimetry Using an Absorbed Dose Portable Calorimeter with Laser-Driven Proton Beams

Round 1

Reviewer 1 Report

Proof-of-principle of absolute dosimetry using an absorbed 2 dose portable calorimeter with laser-driven proton beams

By: Sean McCallum, Nigel Lee, Giuliana Milluzzo, Aodhan McIlvenny, Marco Borghesi, Anna Subiel, Fracncesco Romano (I think that the exact name is Francesco?)

 The paper is important but in its current form it cannot be accepted.

the abstract reports “Study of the so-called FLASH effect have shown promise,…”. To obtain ion beam the authors use very short laser pulse. They do not specify the duration of the proton beams in order to call the effect FLASH.

 Minor changes.

Pag. 2 row 56: clarify the phrase “a potential clinical translation…….”. it is inconsistent.

Page 2 row 91: clarify the phrase “UHDpulse“.

Page 3 row 128 and 129: here the authors report figure 4(a) and figure 4(b). These figures do not exist. Only Figure 4 is present in the text.

Pag. 3 In the figure caption of Figure 3. Use double dot after (a) and after (b). The form “...the pipe to the irradiation point. (b). The..” is equivoque

Pag. 5, row 175: improve the phrase “For the 5 shots performed, the corresponding laser energies produced were 556.0, 592.0, 582.4, 620.9 and 617.7 J, respectively.” Respectively has not sense.

Pag. 8, row 244: improve the phrase “From this, the dose across the 35 mm film layer the is shown to vary according to the effect of the dipole magnet.”

Pag. 10, row 285: improve the phrase “ INFN-LNS, Sicily” with “ INFN-LNS, Sicily-I” 

Major changes.

Pag. 11: Equation (1) is never used in the text. Moreover the parameter V is not specified.

Pag. 12, row 384 the phrase “albeit to a lesser extent than that of the target from which the proton beam is accelerated as has been well established within the TNSA mechanism” This mechanism has never been introduced.

English language is good but the editing needs to be improved

Author Response

Reply attached in uploaded document. 

Author Response File: Author Response.pdf

Reviewer 2 Report

I believe the authors have made a meaningful attempt. They have conducted and presented absorbed dose measurements using a small-body portable graphite calorimeter developed and maintained at the NPL. This represents a novel approach to laser-driven dosimetry that has not been explored before. This method has relevance not only for measuring high-intensity proton beams but also for measuring electron beams or other ion beams.

However, I think the experimental results presented in the manuscript lack sufficient data and analysis, and there are shortcomings in the scientific exposition. The entire manuscript reads more like a lab report, with some details that are not relevant to the readers and lack effective refinement, such as in Section 2. Some parts that are crucial to supporting the conclusions are not thoroughly analyzed, as seen in Section 3.

The limited amount of data makes it difficult to draw reliable conclusions. The experiments were performed with a small number of shots, and the conclusions are based on results from fewer than 5 shots. Some aspects, such as the relationship between temperature variations and pulse width or beam size of the proton beam, should be analyzed even with the limited data. It is evident that temperature variations arise from physical processes similar to isochoric heating, so the temperature changes are expected to depend not only on the dose but also on the pulse width and beam size of the proton beam. Questions arise, such as whether the temperature variations are solely related to the radiation dose of the proton beam, whether the temperature at the NPL is uniform, and whether the observed radiation dose in terms of temperature variations can be extrapolated to proton beams with different pulse widths. These are very important for the final conclusions. 

Furthermore, the authors' figures are rough and need further refinement to improve their presentation.

In my opinion, the limited sample size undermines the reliability of the conclusions and the analysis of uncertainties. However, the method presented by the authors has definite value as a reference for diagnosing high-intensity particle beams, which is currently a challenge. I recommend accepting this work with substantial revisions.

Author Response

Reply uploaded in the same document attached in response to reviewer 1 - the same document has been used to address both reviewers. 

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

The authors addressed the two main concerns I had.

One concern was whether there would be different final temperatures for the same dose of proton beams with long and short pulses when measured using this method, which forms the basis of this work. The authors provided a detailed analysis that convinced me. However, I believe that this explanation should be appropriately incorporated into the manuscript, as it demonstrates the applicability and innovation of this approach, distinguishing it from the extensive experimental work and applications that have been conducted in diagnosing proton beams with long pulses.

The second concern was the issue of limited reliability due to the low number of shots. The authors provided an explanation, acknowledging the limited number of shots but considering the current experiments as a fundamental demonstration. Based on the available data, the authors' analysis of the experimental datas to be meticulous and supportive of their conclusions.

 I support the publication of this manuscript.

Author Response

We have addressed the comments from the second round of reviews and subsequently made appropriate changes to the manuscript. This includes the overall content of the document. Additionally, the English language has been checked - we would point that we find no flaws in the writing of this, 3 of the authors are native English speakers (including the first author and 2 corresponding authors), with all others having complete English fluency for a number of years. We would finally like to once again thank all the reviewers and editors for help in getting the manuscript to this stage. We believed the critiques we have received have furthered strengthened the material and overall content of the script.