[esa-t474] Your Submission (fwd)

[Mark Slater]

Dear All,

	Some good news! It looks like the reviewer liked the paper and 
there are only some relatively minor issues to resolve. The comments are 
below. I'll attempt to sort these out in the next 2 weeks.

Thanks,

Mark

---------- Forwarded message ----------
Date: Sat, 12 Jan 2008 03:40:12 -0000
From: nim at lbl.gov
To: slater at hep.phy.cam.ac.uk
Subject: Your Submission

Ms. Ref. No.:  NIMA-D-07-00900
Title: Cavity BPM System Tests for the ILC Energy Spectrometer
Nuclear Inst. and Methods in Physics Research, A

Dear Dr. Slater,

I have received the reviewers' comments on your paper that are appended
below. They are advising that you revise your manuscript before it can be
published.  If you are prepared to undertake the work required, I would be
pleased to consider the revised submission.
 
If you decide to revise the work, please submit a list of changes or a
rebuttal against each point raised when you submit the revised manuscript.

The revision should be submitted by
11 May 2008 

Revisions that do not address the Reviewer comments point by point will not be considered

To submit a revision, please go to http://ees.elsevier.com/nima/ and click "login" underneath the journal title banner.  You may then type in your user name/password and click "Author Login." 

On your Main Menu page is a folder entitled "Submissions Needing Revision".  You will find your submission record there.  Also, the reviewer(s) may have uploaded detailed comments on your manuscript. Click on the "Submissions Needing Revision" from your main menu, then click on "View Reviewer Attachments" to access any detailed comments from the reviewer(s) that may have been included. 

With best regards,

William A. Barletta
Editor
Nuclear Inst. and Methods in Physics Research, A

Reviewers' comments:


Reviewer #1: I believe this is a valuable, relevant to NIM, and very detailed manuscript. The community will benefit from its publication. I have the following comments, all of which should be solvable by simple editing:

1) The discussion starting with line 441 and ending with line 474 is confusing. I will attempt to summarize my understanding of it: On each shot, eight pieces of data are collected from the outer two BPM's, including the I and Q signals in each direction. The correlations between this data and the the I and Q of the central BPM are analyzed over many shots, such that eighteen linear parameters are found that best predict the central BPM data (nine parameters for I, and nine parameters for Q). 

If that is the case, then the authors should explicitly state that x_i and x'_i in Equation 16 are derived from the I and Q signals of one of the outer BPM's. The phrase "outer BPM coordinates" sounds vague, since coordinates could be taken to mean positions only.

2) In several places (line 178 on p. 12, and later, in lines 671 to 674 on p. 42, line 587, p. 35), the paper talks about unwanted coupling with other modes in the cavity. BPM 1 is said to have rectangular cavities, and I am guessing that the mechanical damage brought the detuned orthogonal mode closer to the filter acceptance window.  Is the artifact in the BPM 4x signal due to the same issue? In that case, analysis of the residual vs. motion in the y-direction would give a much clearer indication of the source of the cross-coupling (if data is available).

3) I recommend the description of the SLAC "A-line" (line 82 on p. 6 to line 121 on p. 8) to be better "decoupled" from the discussion of the ESA beamline. Initially, I was looking for BPM's 1-9 in the Figure 3 description of the A-line, and only realized the general layout of the beamline components after re-reading both sections a couple of times.

4) Table 7: the fourth entry in the table is "Q cavities". I could not find in the text what this refers to. Are these the phase reference cavities?

5) Fig 16 is missing the plot legends.

6) In some of the plots, a label such as "BPM 4x Residual" is easy to mistakenly read it as "four times"  the residual, thus giving the impression that the signal was rescaled by a factor of four. A notation such as BPM-4X might make it easier to interpret the plots. 

7) The definition of "linked" system resolution starting in line 544, p. 32 is a bit vague. Assuming a straight line trajectory through a set of BPM's, the residual of each BPM is calculated, which gives up to eight numbers. At this point, I am confused about whether a single BPM is selected and the RMS value of its residual is called the "linked" system resolution, or whether a further RMS is performed on all the residuals of up to eight BPM's in the set. In the case of a single BPM, how is that BPM selected?

8) Table 8 and its discussion would be clearer if: 1) the table column headings were called something like "Measured resolution, x", and "Predicted resolution, x", etc. and; 2) The sentence on line 552, p. 33 was changed to alert the reader that predicted resolution is defined in the next paragraph.

9) In the discussion of measured system resolution on line 554, p. 33, I wonder if the digitizer was operated near the peak of its range, or would additional signal amplification further reduce the digitizer noise?

10) Figure 18, I can guess that the black points are the mean, and the red region is the RMS width, but it should be stated explicitly. Also, the meaning of the green lines is not at all apparent.

11) In general, the paper would benefit from a statement of the BPM sensitivity (signal voltage for a given bunch charge and displacement),  typical signal levels seen at various points in the processing electronics, a more detailed description of the electronics components used (mixers, amplifier), and a discussion of the likely sources of electronic noise.

12) Minor grammatical errors on lines 587, 654, and 656.