Visible Light Spectroscopy of W¹⁴⁺ Ions in an Electron Beam Ion Trap

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

This manuscript explores the visible lines of W14+ ions in the 400 - 650 nm wavelength range. Most of the observed spectral lines have been tentatively identified through a combination of experimental measurements and theoretical simulations. The work described in the manuscript is of great importance to the field of plasma diagnostics. The paper is presented very clearly and could be considered for publication in Atoms. Still, there are some points that should be addressed. 

1.       In lines L63 - L64, it is recommended that the authors add the specific reference spectral lines used for calibration.

2.       In lines L77 – L78, it is recommended to provide the reasons for adopting these three sets of electron densities. This will help the readers understand the rationale behind the selection and make the research more convincing.

3.       References [27] being an article that is still in the process of preparation and is being frequently quoted might not be suitable. At the very least, relevant literature on the basic theories of MCDHF and RCI should be cited concurrently.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

The manuscript is a conference contribution to the 2024 meeting on highly charged ions. "Atoms" is the journal supposed to publish the conference proceedings. A manuscript dealing with spectroscopic measurements on
trapped highly charged ions therefore is clearly eligible for this journal.

The text is written in a fairly fluent English. However, at a closer look, the authors struggle with the use of "a/the" which do not exist in Chinese, and the sentence structure follows textbook examples that are not necessarily close to practical spoken English.  I am slightly modifying their abstract as an example, but I am not going to edit the full text. There the
authors should be able to find a colleague who has enough experience with practical English to improve the wording and flow.

My (minimally altered) version of the abstract:

"In this work, visible lines of W ions in the wavelength range of 400 - 650 nm are investigated experimentally and theoretically.
The experiments were performed at a low-energy electron beam ion trap.
Simulated spectra of W14+ ions (Nd-like) were obtained from atomic structure computations in combination with a collisional-radiative model.
Overall, there is a reasonable similarity between the measurements and the results of the simulations, and
most of the twelve observed spectral lines associated with W14+ have been tentatively identified. "

Depending on how the evaluation process revealed similarities, or how additional measurements indicated specific ion charge states,
this may be formulated differently, but I have tried to reduce mental duplications.

1. Introduction
plenty of missing/superfluous "a/the"
line 13, insert space before "(ITER)"

line 30, "combined the TOF method" needs to be rephrased to make a sensible phrase

line 31, "sequentially" has a different meaning; Windberger et al. are several persons and therefore the verb has to have the plural form

line 33, "show that ..." is cumbersome and partly misleading; "show a total ... lines as originating ..." is clearer

The last paragraph of the introduction largely contains information that belongs into section 2, where part of it is duplicated.

line 41, a collisional ...

2. Experiment

lines 54/55, The presently clumsy wording should be clarified, may be as
"The ions can be extracted from the trapping region, and the charge state distribution (CSD) be analyzed with the help of a Wien filter mounted behind the collector."

Expand a little on the Wien filter measurement, which indicates the charge state of a group of ions by the time of flight the ions need from the trap to the detector.

3. Calculation

line 70 "..., FAC was ..."

line 71, "collisional"

Table 1, header, "configurations considered in our ... RCI-CRM ... "
Ground configuration (there is enough space)

4. Results and discussion

Figure 2, caption: "spectral"; this last sentence should go before (b); part (b) does not show the CSD, but the signal of the TOF detector behind the Wien filter, with markers for three ion charge states.

line 82, "are shown"
", and no spectral lines of W14+ ions in other visible light wavelength range were observed in the present work" is garbled,
try "  . No spectral lines of W14+ ions were observed in other parts of the visible light wavelength range in the present work"

line 83, "t can be evaluated that the lines, marked with black arrows in Figure 2(a) (the label corresponds to Table 2 and Figure 3), respond sensitively to the electron beam energies" reads poorly, try
"The lines marked with black arrows in Figure 2(a) (the labels correspond to Table 2 and Figure 3) respond sensitively to the electron beam energy"

Fig. 3, "Synthetic" or "Simulated spectrum", surely not "Synthetice sepctrum" ; insert a space after "(b,c,d)"
Anyway, how can a spectrum be synthetic and experimental at the same time? What are lines alpha and beta?
So many mistakes in the same figure and caption - repair!

lines 95-98 are garbled and need to be rephrased.

lines 101-102 " The experimental spectrum of W14+ ions shown in Figure 3(a) is a synthetic spectrum." How that? Explain!

Table 2, table header, add "*" to the column headers 5 and 6. Are the line identifications new? Then column 8 also deserves a "*" and an explanation "* This work" in the caption. If not all line identifications are new, put the asterisk only to the new identifications.

line 125, this information belongs into the figure caption only; delete it here.

line 128, 130 "we could ..." - did you? Then remove "could"

line 146, " a dependence that can be used ..."

Ref. 27, "work in progress"

Why are ref. 19-23 cited? By their titles they have nothing to do with the present study, except that they may have used the same EBIT.
This is not necessary nor appropriate; please restrict your citations to studies that actually by their scientific content relate to the
present investigation.  

At the end of reading I wonder why the initial statements of the manuscript are so weak. It turns out that most of the lines observed have not been observed for the first time. Of course, re-measurements are necessary, as well as checks of previous analyses.
However, it should be clearly stated in the introduction that and how the present study builds on earlier work by others.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf