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Comment: Migrated to Confluence 4.0


  1. Page 96: the reader might notice that that RPC are described as glass-based when they are an option for DHCAL, while Bakelite plates are suggested as an option for the Muon system. Not a real criticism, but looks somewhat odd.
    H.Band: It is not completely arbitrary, but different choices on what aspect of the design was most important.
    We could use either material for both detectors.

Glass is significantly heavier than bakelite for the same thickness (2mm) and more brittle.
Given the large area chambers needed for the muon system Bakelite would be easier to construct and install.
Probably cheaper too. The downside is the potential aging problems which
as far as I know have been mitigated at LHC.

The glass RPCs have better aging characteristics. When used in a thinner design (1.2 mm) the stiffness
is an advantage.   I don't think the Argonne group has fully solved how they would build a glass RPC
calorimeter from roughly 1m by 1m squares (or smaller), but they seem convinced that it can be done.
Here the choice was on the safest technology.

Magnet system (Altogether, a well detailed chapter)


  1. Page 138: The equation for the number of Bhabha per bunch-crossing must have something missing, otherwise it suggests order of thousands events per bunch crossing.
    B. Schumm :True - the factor of 8 came from the integral alone, and did not include the pre-factor including the overall cross section scale, the lum, and the bunch-crossing rate. The new factor that replaces "8" is 6x10^{-6}.
  2. Page 138: Theta_min is used in the formula, then as equal for 20 mrad (where it probably refers to the beamstrahlung envelope and not to LumiCal), then as equal to 3 mrad (that is the BeamCal, not LumiCal) after referring to systematic (geometric) errors. Please revise for consistency. Consider also starting the paragraphs below on BeamCal with a new section number.
    B. Schumm :Yes - this was confused. Theta_min is now only used for the fiducial-region boundary, and is
    always 46 mrad. I didn't agree with the statement about the new section number: it all belongs in
    section 8.1.1 on overall design criteria.
  3. Page 145 and following: The discussion of "stau" pair production as example of the relevance of BeamCal for vetoing two-photon background is interesting. However, as it is presented in chapter 8 it seems somewhat out of the style of the document, since other cases of this type are not discussed in the previous chapters, and the reader is expecting to see them collected together as physics studies. You might consider moving this case to that chapter – when it exists - and just refer to it in chapter 8.
    B.Schumm, M. Stanitzki: Done as suggested

Simulation and reconstruction

  1. Page 159: Definition of "voxel": geometrically, is it intended as the smallest unit (i.e.: pixel, or strip, or pad)?
  2. Wiki MarkupPage 161, near the bottom: it does not appear clear the way in which "the primary vertex constraint is \ [normally\] used in the reconstruction of secondary vertices". <span style="color: #0000ff"> The primary vertex is used in the reconstruction of secondary vertices. Normally, the primary vertex is fit with a constraint. The text has been clarified.</span>
    The primary vertex is used in the reconstruction of secondary vertices. Normally, the primary vertex is fit with a constraint. The text has been clarified.
  3. Page 164: consider adding a few words to explain the definition of rms90 for the general reader.


  1. Many sections are missing: starting with jet finding algorithm, and going over the benchmark processes: top Yukawa coupling, Higgs branching fractions, Beam polarization and triple gauge coupling, top cross-section and asymmetry.