Behavior of a multiloop dc superconducting quantum interference device

Measurements of low inductance dc superconducing quantum interference devices (SQUIDs) are presented. The SQUIDs used for such measurements are made using a photolithographic technique similar to that one developed by IBM for the superconducting computer. On the same chip a coil is evaporated with a coupling coefficient k to the SQUID larger than 0.33. The best measured intrinsic energy sensitivity is 4 h. Possible improvements in the design are proposed.