View source for Instrument Paper Comment

Please add comments in appropriate section:
You can also send comments to Aritoki Suzuki at asuzuki@berkeley.edu

When editing, please follow style suggested by Maria

* '''Style consistency (suggested by Maria)'''
** in the text use words for indicate numbers for example: from "1 or 2 bands" to "one or two bands". Another example: "three-axis mount" instead of "3-axis mount". But for expressions as 1000 TESes, use numbers not words.
** Preferring CMB-S4 instead of S4 (few times in the next S4 was used). 
** Stage-II instead of Stage-2 or stage-2.
** Numbered items listed in the text: (i), (ii).
** ~ for space doesn't work. Use instead \, .
** Medium size space between number and unit of measurement: 15\,GHz instead of 15 GHz or 15GHz.
** Ranges of numbers, for example: (120--280)\,GHz instead of 120-280 GHz (since GHz refers to the entire range).
** Lowercase for indicating the name of materials: alumina instead of Alumina.
** Caption of figures/tables:\emph{ (Top) bla bla bla bla. (Left) bla bla bla}.

=== LATEX style ===
# Bunch of \newcommand (and similar) defined after \begin{document} in the cmbs4_instbook.tex, although it doesn't seem to cause any failures, it feels like many of those commands should live in the preamble. See for example the ADS abbreviations. It would be useful to clean up this file to improve readability. I think it generally makes it easier for people to contribute to the document.

=== General comment === 
# I was actually a bit surprised by the existence of both a Conclusion and a Summary for each chapter -- my first thought was "What's the difference?". You may want to make these Summaries sub-sections of each Conclusion (maybe...) and/or call them Status Summaries (to make it obvious that this is not just repeating the Conclusions). But in any event I would motivate the Summaries a bit more in the final paragraph of chapter 1. That is, I would expand what you have now:

We have developed two readiness figures of merit. The Technology Status Level (TSL) and Production Status Level (PSL) give a means to compare technologies directly. The definitions of the TSL and PSL are given the in Table1-1. To allow direct comparison of the TSL and PSL will be given for each technology in this technology book.

to something like

At the end of each chapter [...or, at the end of each chapter's conclusion...] the reader will find a Status Summary in which we tabulate the maturity of the technologies discussed in the chapter. We have developed two readiness figures of merit -- the Technology Status Level (TSL) and the Production Status Level (PSL). These are intended to give the reader a means to compare different technologies directly. Their definitions are given the in Table1-1.

and you may want to make sure the figure captions of each of the tables in each of the Summaries makes reference to Table 1-1.

=== Acronym Table: Bibliography ===
* Readout chapter, Acronym missing definition
* Receiver optics chapter, Broken citation link

=== Executive summary ===
# In the Executive Summary, I liked the Receiver Optics and Focal Plane Optical Coupling parts. They get the basics across "smoothly".

The Telescope Design and Focal Plane Sensors and Readout sections were a bit choppier -- with different levels of paragraphs and subsections. For example, the paragraph about computer simulations for FSLs might be too detailed for the Executive Summary.

In the receiver optics part of the Executive Summary, the first paragraph implies that larger sizes would be nice, but then each bullet point afterwards says that larger sizes are *needed*. It seems sort of contradictory.

=== Introduction and Conclusion ===
# Please add comment here

=== Telescope design ===
# Each of chapters 3, 4 and 5 start immediately with an Introduction, and finish with a Conclusion and then a Summary. Chapter 1 is obviously different from the other chapters, but chapter 2 should probably be edited to follow this pattern as well (move the initial material at the beginning of the chapter to the Introduction and create the Summary for chapter 2).
# Will be exceedingly cross if the word "eyepiece" EVER appears in a description of the BICEP/Keck telescope descriptions.  At some point it appeared in Keck documents and papers and I have not been able to kill it.  Currently exists in the draft in 2.2.1, 2nd para. Should read: "Each is a simple two-lens objective/field lens design with a stop."  (also changed grammar a bit)
# BICEP-3 section complete?

=== Receiver optics ===
# It would be better to have some of the definitions in the beginning of chapter 3 rather than in between. For example, loss tangent is used everywhere, however it is defined wonderfully in 3.7.3 Another example is with the VPM.
# Missing captions for summary table
# Some citation are still [?]
* \cite{Dumitrescu}
* \cite{Zhang09} (https://arxiv.org/pdf/1107.3560.pdf)
* \cite{spider}
* \cite{Salatino10}
* \cite{bryan2010a}
* \cite{Reichborn-Kjennerud10}
* \cite{zilic_thesis}
* Citations in HWP rotation mechanism

=== Focal plane optical coupling ===
# Missing captions for summary table

# First, Big Comments:

* Section divisions and flow:  
	— 4.3.1 and 4.3.2 are certainly describing different parts of designs, but 4.3.1 (Feedhorns) says it uses OMT coupling and 4.3.2 (OMTs) says it uses Feedhorn coupling.  So aren’t these effectively the same category of choice for RF coupling (i.e. a feedhorn to OMT)?  So these should either be two subsections of one section “feedhorn and coupling” or it should be clear somewhere why these things are not as interrelated as they are made to seem in the text.
	— 4.3.4, 4.3.5, and 4.3.6 are all describing variations on a theme: lenslet-coupled antennas.  Why are they broken out into different sections?  Maybe these should be sub-sections of one lenslet-coupled section, and each subsection describes a different established process for making this type of interface.
	— 4.3.3 should probably be the last of the sections in 4.3, since it couples do a different detector type, or at least discusses heavily that detector type (KIDs), whereas the rest are implied coupled to TES (or at least don’t discuss detector technology).  

* Big Comments on 4.3
	— The sections in 4.3 are different in terms of the scope they attempt to cover, and the number of pages dedicated to each topic.  4.3.3. (KIDs) has a long and detailed description, and there is more detail in 4.3.4-4.3.6 (Lenslets) than there is for example in 4.3.1 and 4.3.2 and 4.3.7.  Is this what you want?  
	— 4.3 Generally: An even-handed approach in terms of scope of description and level of detail would be good.

*  I noticed that for some technologies, certain labs/universities are called out as the places they are being developed, and for other technologies they are not.  It should be consistent across the board — either calling out who is making each of these things, or only calling out which experiment is using each of these things.

# Specific Comments on sections of the document:

*  Acronyms: 
FNL is not defined in the acronym list

* Section 4.2.2: An explanation of why band centers are not the same between 3 and five band simulations would be good.

* 4.3.0
— SPT-3G has already deployed these lenslet-coupled devices.  Fix the tense.
— Why do you talk about lenslet- coupled devices and horns here in the introduction, but not the other technologies?  This opening paragraph should reflect exactly the order and discussion of the sections in the rest of 4.3, be even handed across the sections that are going to be discussed, and not call out specifically only a subset of experiments.

* 4.3.1
— The word “platelet” is used with no description, and I don’t know what that is.

* 4.3.2 
— Acronym definition: here and elsewhere.  You define CPW, which is already defined at the front of the chapter.  Do you want to re-define things in their first usage in the chapter, or leave it to the list of definitions?  This should be edited for consistency across all acronyms.
— "OMT coupled feedhorn technology demonstrated frequency scaling above 300\,GHz.”  I don’t know why this sentence is here - we’re presumably only interested in frequencies <300 GHz.  This sentence also isn’t quite grammatically correct, but since I don’t know the message it is supposed to convey, I can’t fix the grammar.

* 4.3.4
— IDC is defined here and in the acronym table.
— Is it dielectric constant or index of refraction that governs how big the antenna has to be when embedded in dielectric?
— “substrate mode” is jargon.
— define “AR” in the acronym list
— Define “HWP” in the acronym list. 
— Do we need the sentence about HWPs at all? It seems like a non-sequitor.  In fact, I commented out that sentence.
— The level of detail in this section is more than in some other sections.  I propose the following sentences are too much detail and should be removed:
	The silicon lenslets were AR coated with thermoformed Ultem-1000 plastic \cite{Quealy}. 
	The ellipticity of the feed is $< 1\%$, and the cross-pol is better than -20\,dB in D-plane. 
— "As described in Section~\ref{sec:bandwidthresolution}, pixel size with small $F\lambda$ is preferred for a ground based experiment. “  I don’t want to mess up the meaning here, but this sentence needs a grammatical change and I don’t know how to do it without changing the meaning.  Is it that the pixel size that gives a small F/lambda is preferred?  Or is it that a small F/lambda is preferred, which leads to small pixel size?  
— “expansion factor” is jargon.

* 4.3.5
— The “demonstrated performance” section here especially is very detailed compared to the rest of the document. I suggest this be a subsection of the previous section, and shortened by about half.   Nowhere else is the fab process discussed in this much detail of exactly how things are made. For now I have fixed the grammar/usage so it at least reads more smoothly.
— In “demonstrated performance” The tense jumps back and forth between present and past.  I tried to fix it, but a double check would be good.
— I nominate “the requirements for CNC adaptation:…” sentence and the following sentence to be removed. 

* 4.3.6
— “GRIN” is defined here and at the front of the chapter.

* 4.4.1
— “Demonstrated performance” The level of detail is a bit higher here than in other places, but probably OK.  I would reduce by a couple sentences.

*4.4.2
— Figure 63 is messed up in my compiled version

*4.4.3
— First sentence: describe what a microwave cross-over is.
— what are “wings”?  The first instance of wings does not say what they are.

* 4.4.4
— No “Scaling for S4” section here?

* 4.5.1
— "Modular optics tubes design that each focus light onto one array optically separates adjacent wafers to avoid dead space problem between wafers.”  I don’t know exactly what this sentence is trying to say, but it is not quite grammatically correct right now.

=== Focal plane sensor and readout ===
# Missing captions for summary table
# Missing acronym definition (Acronym table at end of chapter) 
# Section 5.4.2 - In the previous section, it was stated that the TDM architecture described is very different from the one used in SCUBA2, BICEP2 and ACT, so this statement ("The TDM architecture described above is now very mature and has extensive field heritage on a variety of CMB instruments including...") is confusing.
# Section 5.5.3 - This section is the first section that mentions technology/production status level; other technologies described above did not include a discussion of PS/TSL. Consistency