Accurate measurement of the electron beam polarization in JLab Hall A   using Compton polarimetry
  A major advance in accurate electron beam polarization measurement has been achieved at Jlab Hall A with a Compton polarimeter based on a Fabry-Perot cavity photon beam amplifier. At an electron energy of 4.6 GeV and a beam current of 40 uA, a total relative uncertainty of 1.5% is typically achieved within 40 min of data taking. Under the same conditions monitoring of the polarization is accurate at a level of 1%. These unprecedented results make Compton polarimetry an essential tool for modern parity-violation experiments, which require very accurate electron beam polarization measurements. 
S. Escoffier, P.Y. Bertin, M. Brossard, E. Burtin, C. Cavata, N.   Colombel, C.W. de Jager, A. Delbart, D. Lhuillier, F. Mar...