General remarks: - figures need to be consistent and use a common macro

- many references are missing or not correctly referred to

- some figures were not approved: it might be good to give the list of these figures to make the collaboration aware of them when reading the draft

- At this stage: I think the most crucial part of the document is Physics performances (plot not approved and sections are missing)

- in some part we mention the group who did work, sometime not: what is the policy here?

- provide references as much as we can for the results or statement we make

- Section 2.3 "Technical Design of GE1/1 chambers for CMS" I think a large part (or all of it" would go into chapter 5.

CHAPTER 1:

- page 1 many typos due to Tex (? instead of ><..)

- l167 GE1/1 is not mentioned before, or do we assume the reader knows it already?

- l170 updated numbers missing

- l210: gain of 15000 for triple GEM: a reference is needed, in addition to the conditions (gas mixture,…)

- l222: give the area the GEM will cover

- There is a part from chapter 2 that can be in this chapter. It is the part of section 2.1.3 which talks about the experiment using the GEM already. Since this chapter is talking about motivations, this could be another one in favor of GEM technology.

CHAPTER 2:

- p5 last line of section 2.1: gas mixture is missing

- Figure 2.1: add Left and Right to distinguish between the figures in the caption

- Figure 2.2: we can provide a better (good resolution) picture. Also we need to change the collection to induction to be consistent with the text

- l282: the statement about the 5-8% variation of the gain with the hole diameter should be justified with a reference

- Section 2.1.2 needs editing: I propose the following: first start talking about the important quantities when choosing a detection technology: gain, efficiency, resolution, robustness,… Then we should talk about the important parameters affecting these quantities, among them the transport parameters. Then we can start our details on these transport parameters.

- figures 2.3 and 2.4 (both left) are exactly the same

- l345: remove "we can expect"

- subsection 2.1.3 should go to chapter 1 in my opinion

- l359: "the detectors operate at 2.5 kHZ/cm2 which corresponds to 1000 times the expected rate " this is sentence does not match with line 267 where we talk about an expected rate of "5kHZ/cm2"

- l384: sometimes we talk about the ionization dose "in Gy" and other times we talk about "accumulated charge". I think we should be consistent not to scatter the reader's attention.

- l396: again here we have a discrepancy the integrated charge in 10 years is "120 mC/cm2" whereas in l289 we talk about an integrated charge of "100 mC/cm2" for 20 years.

- subsection 2.2.1 someone should take care of it and include all papers and relevant results as mentioned

- section 2.2.2.1 we talk for the first time about the effective gain and we should define it as well as the total gain

- l558: remove "The group at TAMUQ"

- figure 2.21: the title is "Schematic view of the GEM cell geometry as modeled by ANSYS"

- l576: FIXME should be figure 2.22

- remove figure 2.26 (not yet approved)

- l584: remove all red part since it is not ready yet

- l594: Timing resolution should be in a new line

- l598: figure is missing

- l602: Inducing gap should be induction gap

- figures 2.27 and 2.28 captions missing

- Section 2.3 "Technical Design of GE1/1 chambers for CMS" I think a large part (or all of it" would go into chapter 5.

CHAPTER 3

- l804: the description of the biredictional paths of the opto-hybrids is confusing.

- l812: "readout on GEM" should "readout of GEM"

- l821: "a duration of many tens" should be "duration of several"

- l835: Trigger granularity: I do not understand: if VFAT2 has a granularity of 16 and GEM has a trigger granularity of 2, why we are talking about increase in granularity?

- l872: I think this sentence should be removed or re=phrased "This document aims to brought …"

- l875: is it relevant to mention "silicon detectors" here?

- Table 3.1: remove "table" from the caption

- l882: signal to noise "ratio". Also "maintain" should be "maintained"

- l884: "shaping time of 100ns.." give reference since we are talking about previous results

- l894: e-port should be E-port

- l910: header CC-E does not appear in figure 3.5 (Am I missing something?)

- l918: Which Figure number: I think it is Figure 3.5

- l921: explain why most of the chips will record nothing (low hit rate)

- l965: SLVDS: this acronym is the first time to be used (I f I am correct), we should give the full name

- l991: "It's principle" should be "Its…"

- section 3.4.1" the Gigabit Transceiver is sometimes referred to as GBT and sometimes as GBTX

- l1010 the CMS data bandwidth is 3.2Gbps: do we need to refer to a text or paper here?

CHAPTER 4

- Figure 4.1 is not referred to into the text

- l1075: "sent-out BY the chip" by is missing

- l1081: table 4.1 is not showing VFAT3 data. It is showing latency information. I think a table is missing here.

- figure 4.2: if possible please indicate the "opto-hybrid on the GEM" as well

- l1157 "the tess among others OF the signal"

- l1178 "in Table 4.2"

- l1196: "that XDAQ" should be "than XDAQ"

CHAPTER 6

- Table 6.1 is not referred to in the text

- caption of table 6.1 should below the table not above?

- section 6.2 and 6.3 are very short compared to others?

- l1440: something is missing: I think "regional level"

- p65 the line before the first equation (6.1) contains a "trajectory" term that can be avoided

- l1491: what is "R_T^-1"?

- l1496: what is "L^-2"?

- from l1501 to l1510 need to be re-phrased. It is not clear for me.

- l1714-l1716: the way how the error is obtained is not clear and should be re=phrased

- figure 6.4 and 6.5: some legend are very small and could unreadable

- subsections 6.5.2, 6.6, 6.7 and 6.8 are missing or poorly populated

- l1772: figure missing

- l801: (see plots) which plots? new ones that are not shown?

-