Kinetic Inductance Detectors (KIDs) for the SAFARI Instrument on SPICA

Kinetic Inductance Detectors (KIDs) with frequency domain read-out are intrinsically very suitable to use as building blocks for very large arrays. KIDs therefore are an attractive detector option for the SAFARI instrument on SPICA, Millimetron and also for large scale ground based imaging arrays. To study the properties of large KID arrays we have fabricated 400 pixels array made from 40 nm thick Al films on high resistivity Si substrates. The array is tested in a dry dilution refrigerator at 100 mK. We present the device design and experimental results. We also present a new design of the array with lithographic air bridges over the coplanar waveguide feedline. The air bridges are designed to suppress the slot line mode in the feedline and that will improve the pixel to pixel reproducibility of large arrays.