M.I.Faley, U.Poppe, K.Urban, D.N. Paulson¹, T.N. Starr¹, and R.L. Fagaly^1
1Tristan Technologies inc., San Diego, USA

We have fabricated HTS dc-SQUID flip-chip sensors with large area multilayer flux transformers. Different layouts of the flux transformers provide a large variety of magnetometers and planar gradiometers. For the magnetometers a resolution ~6 fT/SQR(Hz) and the planar gradiometers a resolution of about ~30 fT/cm SQRT(Hz) were routinely obtained at 77 K. The noise was nearly white down to frequencies of few Hz. The sensors were vacuum-tight encapsulated together with a heater and a feed-back coil. This makes the handling of the sensors more reproducible and convenient. Production of the magnetometers and gradiometers in small series was proven.