Low-Background Shielding Box for Autoradiography of Environmental Samples and the α-, β-, and γ-ray Sensitivities of the Imaging Plates
Round 1
Reviewer 1 Report
Review of manuscript applsci-637290 “Low-background shielding box for autoradiography of environmental samples and the α-, β- and γ-ray sensitivities of the imaging plates ” by Shizuma K. & Oba Y.
This manuscript presents the results of several experiments aimed at defining the potential of a large size box for autoradiography in shielding natural low radioactive background and provide effective images of radionuclide distribution in environmental samples. The first part of the paper describes the experimental activities for the definition of background characteristics and IP sensitivities to α, β and γ rays. The second part describes the application of the shielding box to autoradiography of sediments, fir tree and mushroom specimens contaminated by the radioactive fallout of the Fukushima Nuclear power plant.
General comment
The research is really interesting and precisely described in order to be understandable also to researchers like me that are not specialized in this field. Nevertheless I would suggest to better address the differences of this shielding box with respect to already existing one that are available for measurements and to underline the pros and cons of every available box. For example, at lines 79-81 authors write that “...a large shielding box 70x50x20 cm in size...” has been already built “...to investigate long leaves contaminated by 137Cs.”. I then wondered why building a box 35x40 cm in size as the one described in the paper if a larger one already existed? Could the authors provide further information in order to answer this question? Are the performance of this shielding box better than the others?
Specific comments
Table 1: use emission probability instead of intensity in the column at the right side of the table.
Line 82: We designed a large LEAD shielding box…
Lines 97-99: provide references to sustain that “ Saran wrap is easily charged during unrolling….”.
Please, check that data reported in Table 1 fits with those written in sub-chapters 2.3 and 2.4 (e.g. line 113 reports an emission probability of 83.2 % per decay, while Table 1 reports 85.2%; line 142 shows the same discrepancy for 40K).
Line 143: is it electron capture decay or emission probability? Please check and correct if necessary.
Line 147: PSL mm-2 H-1
Check all letters and numbers throughout the text that should be superscript or subscript (137Cs, 40K, mm-2h-1, μAl , etc.)
Line 151: Background count rates are shown in Fig. 3, not Table 2. Please, correct this mistake. In addition, the reported Table 3 is Table 2 (line 206).
Lines 162 and 165: 214Pb not 212Pb. In addition, it is not the decay you are measuring (line 165) but the reduction of count rate.
Line 171: The sentence “The Al absorbed thickness was varied from 0,015 to 0,3 mm” is a repetition and could be deleted.
Line 182-190: Do you need to calculate the α-ray range in al in order to establish the best absorber thickness? If so, please clearly state it in the text.
Line 189: the density of al is 2.7 kg cm-3, not 2.7 103 kg cm-3
Please, better explain why you calculated μAl and μm and how these parameters are used in your research.
Lines 211 and 219: Please, provide some statistical parameter (e.g. R2 of the calculated curve) to sustain the good agreement between measurements and theoretical curves.
Lines 301-304: The migration of radioactivity along the axial spine of the fir tree is a very interesting process and, if verified, could have an important role in the development of radioactivity protection measures. Could you please provide further discussion on this topic and hypotheses of the biological process that promotes this migration?
Lines 346-347: What is the correct year of publication? 1984 or 1988?
The language needs a careful check by a native speaker or a skilled scientist, in order to avoid typos or bad constructed sentences.
Conclusive remark
I don’t feel sufficiently expert in this research field to express a judgement. I then rely on the Editor for the final choice. I can just say that the topic looks very interesting and is well described.
Comments for author File: 
Comments.pdf
Author Response
Answer to Reviewer 1
Thank you for your reviewing of our manuscript.
General comments
A large shielding box was already built,but it was not so convenient. because the door of the shielding box was about 110 kg and heavy. It is important to handle the shielding box safely. We have applied heavy weight wheels for opening smoothly.
Special comments
Table 1: "Emission probability" was used.
Line 82: "a large LEAD shielding" was used.
Lines 97-99: I think it is well known that Saran wrap is easily charged up during unolling. Therefore I can't find out some references.
Table 1: Consistency to 2.3 and 2.4
Thank you for pointing out the consistency of Table 1. I have checked and revised all data in Table 1. I added a reference which cited these data.
Line 143: 40K makes branching transitions to 40Ca (beta - decay with maximum energy 1.31MeV, 89.1%) and to 40Ar (electron capture decay, 10.8%). In the present case, only the beta -decay process is important.
Vertical axis was revised to "PSL mm-1 h-1)
Superscript and subscript
I am very sorry that our edited manuscript was not corrected to be super script or subscript and Table 2 was missing. Therefore it was very difficult to judge it.
Line 151: It was my mistake that background count rates are shown in Fig.3. I added Tables 2 and 3.
Line 162 and 165: It was my mistake that 214Pb is correct. We are measureing not the "decay but the reduction of counting rate".
Line 171: These sentenses are not repition. The rapit decrease comes from alfa rays and almost constant count rate is comes from gamma-rays.
It was my mistake. The density of Al is 2.7kg cm-3.
myu- m and myu- Al: The reason why myu-m and myu-Al is to be calculated is necessary to explain experimental results shown in Figs 5-10.
Lines 211-219: I am very sorry I did't calculate R2. The purpose of thta work is to explain the trend of experimental results.
Lines 301-304: The migration of radioactivities in fir tree is remarkable. I have no more information and biological process is out of my professional.
Lines 346-347: The date of the acqnouledge of the translator was 1986.
I will ask English editing servive and improve our manuscript.
Author Response File: Author Response.pdf
Reviewer 2 Report
In the paper entitled “Low-background shielding box for autoradiography of environmental samples and the α-, β- and γ-ray sensitivities of the imaging plates” the authors describe a featured application designed to serve as a protecting box to be used during autoradiography of environmental samples. Considering its innovative profile, I believe that it could be interesting to accept its inclusion in this journal, as it presents a new product to be used in this scientific application, with certain conclusion about IP’s sensitivity that deserve attention in radioactive monitoring of environmental samples. In such context, I would like to suggest the approval of this manuscript with minor revisions that should be implemented to improve certain details of this paper.
(line 3) It should be used “α” instead of “α-“;
(lines 37-38) The transition between different topics is not clear, and it should be improved the introduction to the topic of autoradiography;
(line 47) The appropriate notation to write the names of radionuclides was not used;
(Table 1) Why 90Y is cited as “(90Y)”? Reference for nuclear data should be cited;
(line 81) Again, revision of radionuclide notation is important. Please review the entire manuscript in order to accomplish with appropriate notation (e.g.: 137Cs);
Author Response
Answer to Reviewer 2
Thank you for your valuavle review.
We have revised according to you comments.
We asked English editing service.
Line 3: I asked English editing service and some of them are . agree with you but English editing service returned some of them.
Line 47: I am very sorry that our edited manuscript was not properly corrected.
I hope the revised manuscript is OK.
Table 1 : The radioactive source was purchased as 90Sr. Since radioactive source 90Sr and90Y are in radioactive equilibrium, 90Y is given in parenthesis.
I have checked all radionuclide notations.
Thank you for your coorporation.
Reviewer 3 Report
This paper shows the development of imaging plate autoradiography system for large –size samples including beta and gamma emitters with the low-background shielding. The environmental gamma-rays are a critical background. The alpha emitter originating from radon captured on a shielding box also makes a background. It is pointed out that the radioactivity of radon captured on an Al absorber is weaker than that on a Saran wrap. The sensitivity ratios of beta/alpha-rays to gamma-rays were measured as a function of the thickness of an Al absorber for various radioisotopes. In most cases, the sensitivity of charged particles is higher than that of gamma-rays by a few orders of magnitudes. The samples near the Fukushima daiichi nuclear power plant in Japan, which include 134Cs and 137Cs, were measured.
One of advantages of the system is it is possible to measure large samples, and it is demonstrated using Fukushima samples such as Momi fir. The detailed design for the measuring system is useful. There, however, are many unclear descriptions. Thus, I could recommend the publication of this manuscript after some changes.
1) English is poor. There are unlogical or unclear sentences and many grammatical errors. I recommend using English editing services provided from major publishers such as Springer-nature, Elsevier, etc after correcting unlogical descriptions.
2) There are too many abbreviation such as PSL, IP, RPG. Because the Applied Sciences is a common journal, audiences are not know well such abbreviations concerning IP. Thus, the full-length word is better than the abbreviation.
3) “Saran wrap” is the registered trademark in some countries, and “polyvinylidene chloride file” is a common name. The positions of them should be inverted.
4) There is no Table 2.
5) The size relative to a 3 inch x 3 inch NaI detector and the energy reclusion (FWHM) at 1.3 MeV of the Ge detector is useful.
6) There is no experimental error bar for the PSL intensities in the figures 5-10. The figure 3 shows the relatively large errors for values in the range of 1-10 PSL mm-2h-1. The measured values in figs 5-10 scatter around the evaluated line. This result suggests that even if the statistical error is small the systematic error is large. The total errors for these data and the discussion how to evaluate it are required.
7) How determine the N_beta/N_gamma ratio for 60Co, 137Cs, and 40K ? The authors wrote as “the ratio of the count rate with no absorber to that with an absorber”, but there are many absorbers with various thicknesses.
8) In the case of 40K, the estimated gamma-ray PXL (PSL ?) is much higher than the measured value at 5 mm. Why ?
9) What is the hot spots located near the bottom of the two-years old shoot in the figure 12 ?
10) What is “KBr powder” ? Kalium bromide power ?
11) Figure 3 shows the background as a function of the shield thickness. The authors stated that the small difference between the 5-cm thick and 10-ch thick leads originated from that the IP sensitivity for beta-rays is higher than gamma-rays. The 5-cm thick lead shield is thick enough to absorb almost all beta-rays from outsides. Why the difference occurs ?
12) What is RAI ?
13) There are no definition, macro m, rho Al in equations (4) and (5).
14) There are two dashed lines in figures 7-10. One of them should be changed to another type line such as dot line.
15) The maximum energy of gamma-rays is not used.
Author Response
Anser to REviewer 3
Thank you for your review.
We have revised out manuscript according to your suggestions.
1) We will ask English editing service.
2) The abbrevation of RPG was deleted.
3) I agree to Reviewer. I put "polivinilidene cloride film" first and then put "Saran wrap".
4) I am very sorry that Table 2 was missing. It was dropped in editing manuscript.
I hope it will be OK in our revised manuscript.
5) I am very sorry I do'nt understand the meaning of the sentences.
6) I did'nt give error bars, because all figures 5-10 are not so precise but roughly indicate the trend of the curves.
7) The ratio of Nb/Ng were determined from the counting rate at the absorber thickness =0 (Nb), and almost constant counting rate (Ng).
8) It was my mistake to use PXL.
9) I have no definite answer to this question. It means the surface of the plant is highly contaminated even now.
10) It is Potassium bromide powder. I have exchanged the order. I put "Potassium bromide powder" first and then put KBr.
11) As reviewer pointed out, beta rays are stopped in 5-cm-thick lead. However imaging plate has some sensitiviy to gamma rays. Therefore shielding effect is small compared to the case of Ge detector.
12) ro- Al is the dinsity of Aluminium, myu-m is mass attenuation coefficient.
I have added explanation of of these parameters.
13) I have used two kinds of dashied and dotted lines, but they were not clear.
Therefore I have revised them more clear.
14) It was my mostake. " Maximum energy of gamma-rays" were deleted.
(No.13, 14, 15 should be No.12, 13, 14)
Thank you for you coorpolation.
