deletions | additions       diff --git a/Beam polarization.tex b/Beam polarization.tex  index 1738380..857e0a7 100644  --- a/Beam polarization.tex  +++ b/Beam polarization.tex 
...
\subsection{Beam polarization}  Transverse beam polarization builds up naturally in a storage ring by the Sokolov-Telnov effect. Transverse polarization was measured and used at LEP for energy calibrations up to 61 GeV per beam, this upper limit being determined by machine imperfections and energy spread [17], which becomes commensurate with the spin-tune $\nu_s = . E_{beam}[GeV] /0.440665$.  Given that the energy spread scales as $\sigma_E \propto (E_{beam})^2 E_{beam}^2  / \sqrt{\rho}$ (where $\rho$ is the bending radius), its effect on the achievable polarization should be reduced in TLEP, so that beam polarization sufficient for energy calibration should therefore be readily available at TLEP up to 81 GeV, i.e. the WW threshold. A new machine with a better handle on the orbit should be able to increase this limit: a full 3D spin tracking simulation of the electron machine of the Large Hadron-electron collider (LHeC) project in the 27 km LHC tunnel resulted in a 20\% polarization at beam energy of 65 GeV for typical machine misalignment [18]). Polarization wigglers as described for LEP % in~\cite{Blondel-Jowett-LEP606}