Subject: Manuscript ID EPJA-102933
From: carlo.broggini@pd.infn.it
Date: 06.03.15, 11:50
To: hatta@depni.sinp.msu.ru, kostya.proxy@gmail.com

06-Mar-2015

Dear Dr. Stopani

one of the referees of your paper EPJA-102933 suggests some minor
modifications as you may take from the report attached. Please
consider the proposed changes and resubmit through Manuscript Central
the modified manuscript which I shall be happy to consider again for
possible publication in EPJ A.

Please, note that you have 6 weeks time from now to submit the revised
version. In case it is not possible to upload your revision within
this time period, please advise the Editorial Office to postpone the
deadline.

Sincerely yours
Prof. Carlo Broggini
carlo.broggini@pd.infn.it
epja.bologna@sif.it


NOTE for Editor
Please, make sure that all referees' reports are duly enclosed.

Referee: 1

Comments to the Author

In this paper data taken by activation technique from photon
bremsstrahlung on Bi target are presented together with a wide
phenomenological analysis and discussed.  The results sound
reasonable, in agreement with previous published data.  I have only
few remarks:

- I would suggest to add in the Introduction a wider presentation of
  the physical interest of the study of 209Bi in the present energy
  range,

- it is my personal opinion that the uncertainty discussion of the
  experimental data is very poor: a wider analysis (statistical and
  systematic) of every uncertainty source, related to the used
  experimental technique is needed (for instance it is not clear to me
  what is the uncertainty of the monitored photon flux).  In the
  irradiated target are there competitive activations due to other
  nuclei then bismuth producing physical background and what are their
  weight?  The experiment background deserves a wider attention and
  discussion.

What are the advantages and the drawbacks of investigating by photon
activation technique the neutron/proton emission cross section of
209Bi in this energy range?  The cross section figures are reported
always without any error indication (neither statistical nor
systematic), even in the captions of the Tables shown in the text.  I
think it would have a stronger meanings comparing computed data with
experimental ones if the latter are accompanied by their
uncertainties.

It is my opinion that the present paper, with the recommended
corrections, would be suitable for publication on EPJA.

Referee: 2

Comments to the Author

The paper presents results of multiparticle photonuclear reactions on
Bi209. Interesting results are obtained and compared to various
predictions of statistical models and with previous measurements.

The paper is really well written: the use of cross sections of
photonuclear reactions is mentioned and it’s clear the use of the
model calculations when there are no reliable measurements of the
reaction cross section.  The importance of the use of the photon
activation technique to identify individual partial reactions by the
final nuclei they produce is underlined, as well as all details of the
setup and analysis procedure. In this case a bismuth target was
irradiated with bremsstrahlung photons produced by the electron beam
of the RMT-55 microtron. Using a high-purity germanium detector,
spectra of induced activity have been measured and yields of
photonuclear reactions up to (gamma, 5n1p) and (gamma, 6n) have been
calculated. Model calculations and evaluated photoneutron cross
sections are well described. All experimental yields have been
compared to the results of previous measurements and to predictions of
evaluation in an exhaustive and detailed way.  Various works, both
theoretical and experimental, have been correctly cited and used.  The
paper is a useful piece of a wide work done from the authors on this
field.  The length is appropriate for the proposed journal.

In general I appreciated a lot the paper, my main concern is only
related to the fact that it should be a bit more self-consistent: it’s
nice to send to references for details but some important infos should
be present. This will not affect the length and/or the weight of the
paper but will help a lot the reader.

Other issue is that sometimes I don’t see errors quantified. I wrote
explicitly below.  In general I’m pretty sure you can include the
comments, so I don’t need to review the revised version.

In the following my few comments:

Introduction - page 1/8

Line 40: put the web sites on the references of the codes (references
[5] and [6], see later)

Line 45: bremsstrahlung beam: please specify from where the beam is
coming and how it is obtained. I think it is worth to write something
like “bremsstrahlung photons produced using the electron beam of the
55.6 MeV racetrack microtron RTM-55 of the Skobeltyn…(SINP MSU)” with
a correct reference. Later, in the second section it is referred to
Ref.[23], that is an old proceeding done for the commissioning,
available on
https://accelconf.web.cern.ch/accelconf/r10/papers/thchd01.pdf, I’m
wondering if there is something more recent available.

Experimental Technique - page 2/8 

Line 33: All details of the setup and analysis are given in
Ref. [20-22], in particular everything can be extracted from NIM paper
Ref.[22] but I think it is important to spend few lines for a short
summary and a sketch of the setup for the experiment. For the same
reason, some details, like the “energy spread” is missing.

Line 45: HPGe detector, at least the first time it will be better to
have the full name “High Purity Germanium (HPGe) detector” and to
specify its role, something like “to measure photon spectra of
residual activity”. Again, I would appreciate to see here the relative
efficiency and energy resolution.

Lines 57-60/page2 + 1-2/page3: 

- there are not specified errors in Tab.1, as mentioned in the text;

- specify from where the errors are coming (about 5% for the position
  of the irradiated part with respect to the target and about 10% for
  the uncertainty if the thickness of the copper foil used as a
  monitor target)

Model Calculations - page 3

Line 10: a very nice description of the photoabsorption cross section
by different model calculations is made. Referring to the
photoabsorption cross section in TALYS, the Ref.[31] mentioned is a
PhD thesis from 1972: nothing new later?

Evaluated photoneutron cross section - page 6

Lines 2-4: can you quantify the uncertainties of the instrument
function and the corresponding energy shifts?

Lines 52-54: the informations about the match between experimental
data points multiplied by a scaling factor 1.2 when slightly shifted
by 0.15 MeV towards higher energies should be written also on the
Figure 3 or in the label or in the legenda. In the legenda I would put
“combined model”.

Lines 10-12 second column: it should be mentioned the amount of the
errors of the evaluation reported in Figs 4 and 5, and also to
describe them in the corresponding captions.

References - page 8

Already mentioned during the comments, however few suggestions are
reported here again for completeness:

[5] at the end of the reference for TALYS code add the web page www.talys.eu

[6] web site for the GNASH code

[23] see if there is an other reference for the microtron except the
proceeding mentioned

[31] check if there is a new reference a part the PhD thesis from 1972

[39] the correct reference is EPJA 50, 114 (2014)  => [114 instead of 1]

Few Typos
Line 26 page 4: uncorrelated instead of uncorellated
Line 29 page 4: correlation instead of correllation
Line 38 page 4: strength instead of strenth 
Line 5 page 6: exaggerated instead of exagerrated


* All [15/15]:
  1. [X] R1: add a wider presentation of physical interest of 209Bi at
     these energies in the Introduction, why bremsstrahlung?
  2. [X] R1: wide analysis of uncertainties and background
  3. [X] R2: make a bit more self-consistent
  4. [X] R2: p. 1, l. 40: put the web sites on the references of the
         codes (refs. [5] and [6])
  5. [X] R2: Line 45: bremsstrahlung beam: please specify from where
         the beam is coming and how it is obtained.
  6. [X] R2: p.2: it is important to spend few lines for a short
         summary and a sketch of the setup for the experiment.
  7. [X] R2: Line 45: HPGe detector, better to have the full name
         “High Purity Germanium (HPGe) detector” and to specify its
         role, something like “to measure photon spectra of residual
         activity”, relative efficiency and energy resolution.
  8. [X] R2: there are not specified errors in Tab.1, as mentioned in
         the text;
  9. [X] R2: specify from where the errors are coming (5% and 10%)
  10. [X] R2: p. 3, line 10: Referring to the photoabsorption cross
          section in TALYS, the Ref.[31] mentioned is a PhD thesis
          from 1972: nothing new later?
  11. [X] R2: p. 6, quantify the uncertainties of the instrument
          function and the corresponding energy shifts?
  12. [X] R2: Lines 52-54: scaling factor 1.2 shifted by 0.15 MeV on
          the Figure 3 or in the label or in the legenda. In the
          legenda put “combined model”.
  13. [X] R2: Lines 10-12: it should be mentioned the amount of the
          errors of the evaluation reported in Figs 4 and 5.
  14. [X] R2: refs:
      1. [5] add the web page www.talys.eu
      2. [6] web site for the GNASH code
      3. [23] other reference for the microtron except the proceeding
      4. [31] new reference a part the PhD thesis from 1972
      5. [39] the correct reference is EPJA 50, 114 (2014)
  15. [X] R2: Few Typos
          Line 26 page 4: uncorrelated instead of uncorellated
          Line 29 page 4: correlation instead of correllation
          Line 38 page 4: strength instead of strenth 
          Line 5 page 6: exaggerated instead of exagerrated