A magnetically shielded room with ultra low residual field and gradient
  A versatile and portable magnetically shielded room with a field of (700 \pm 200) pT within a central volume of 1m x 1m x 1m and a field gradient less than 300 pT/m is described. This performance represents more than a hundred-fold improvement of the state of the art for a two-layer magnetic shield and provides an environment suitable for a next generation of precision experiments in fundamental physics at low energies; in particular, searches for electric dipole moments of fundamental systems and tests of Lorentz-invariance based on spin-precession experiments. Studies of the residual fields and their sources enable improved design of future ultra-low gradient environments and experimental apparatus. 
I. Altarev, E. Babcock, D. Beck, M. Burghoff, S. Chesnevskaya, T.   Chupp, S. Degenkolb, I. Fan, P. Fierlinger, A. Frei, E. ...
physics.ins-det