My one main comment is to be careful about the tone of the abstract, which currently has warning flag words like "unexpected" and "inadequate." You can reduce these four, story-like sentences of the abstract "On-site measurements of Keck Array showed unexpected side lobes that were terminating on the absorptive telescope forebaffles. Follow-up lab measurements confirmed these side lobes were due to inadequate blackening of the cryogenic telescopes. Although terminating these side lobes on the forebaffles strongly reduces the possible systematic error impact, it does contribute to the optical loading because the forebaffles are warm. Therefore, in late 2013 the five telescopes were upgraded on site with improved interior cold baffles." to just one sentence "On-site measurements of Keck Array side lobes helped identify a way to reduce its optical loading with interior cold baffles, which were installed in late 2013."

Hi Immanuel, I think we should put the whole Keck collaboration on this paper, since we don’t have so many publications and people should be properly credited. On our side at Caltech that would add Howard, Sinan, Alexis, Brendan and Koko. Jamie From: bicep3-cmb [mailto:bicep3-cmb-bounces@mailman.stanford.edu] On Behalf Of Immanuel Buder Sent: Thursday, May 29, 2014 9:28 AM To: bicep2-list; keckarray(a)lists.stanford.edu; BICEP3 Subject: [bicep3-cmb] Draft SPIE Proceedings for Review I'm attaching a draft of my SPIE Proceedings for comments. The submission deadline has already passed, but I've been given an extension until June 13. Things to think about while reading: In previous SPIEs we have given a full author list. I can take the BICEP2 author list from the paper, but I don't know if we have a final Keck author list. Do we want to submit this to the arxiv? My understanding of the SPIE copyright is that we have to submit to the arxiv first if we do so at all. The introduction is pretty light on references; I'd appreciate suggestions for a few key ones people think are worth adding. I'm trying to stay away from anything controversial related to the BICEP2 results and foregrounds. SPIE is not the right venue for it. Section 2 naturally has a lot of overlap with the upcoming beams paper. Abby especially, I'd appreciate your thoughts here. I put in our latest analysis of the 100 GHz NET and a placeholder for 100 GHz map depth. If we don't feel the 100 GHz map depth is ready to publish, I plan to just say it is already deeper than BICEP1. Note: I used the online collaborative paper-writing tool authorea.com (spin off of Harvard CfA) to write these proceedings. Immanuel Buder Postdoctoral Fellow Harvard-Smithsonian Center for Astrophysics (office) 617 495 7567 (office) 160 Concord Ave., M-114C (mail) 60 Garden St. MS 42 Cambridge, MA 02138 ibuder(a)gmail.com