Multichannel optical atomic magnetometer operating in unshielded   environment
  A multi-channel atomic magnetometer operating in an unshielded environment is described and characterised. The magnetometer is based on D1 optical pumping and D2 polarimetry of Cs vapour contained in gas-buffered cells. Several technical implementations are described and discussed in detail. The demonstrated sensitivity of the setup is 100fT/Hz^1/2 when operating in the difference mode. 
Giuseppe Bevilacqua, Valerio Biancalana, Piero Chessa, Yordanka   Dancheva
physics.ins-det physics.atom-ph