\@doendnote{endnote137}{ A good summary of the Muon Collider concept can be found in the Status Report of 1999\protect \nobreakspace  {}\cite {INTRO:ref5}; an earlier document\protect \nobreakspace  {}\cite {INTRO:ref6}, prepared for Snowmass-1996, is also useful reading. MC Notes prepared by the Collaboration are available on the web\protect \nobreakspace  {}\cite {INTRO:ref11}}
\@doendnote{endnote138}{The $\pi $E5 beam at PSI, Villigen, providing a maximum rate of $10^9$ muons/s\protect \nobreakspace  {}\cite {Edgecock}.}
\@doendnote{endnote139}{Experimentalists might argue that extending such measurements as $\tau _\mu $ and the Michel parameters is worthwhile whenever the state of the art allows substantial improvement. However, their comparison with theory is dominated by theoretical uncertainties. Thus, compared to Marciano's ``best bets," they represent weaker arguments for building a new facility.}
\@doendnote{endnote140}{Despite the increased cooling efficiency at low muon momentum, simulations of an entire muon production section and cooling channel suggest that momenta near the ionization minimum represent the global optimum for Neutrino Factory performance.}