High Q Niobium superconducting resonators for use as Kinetic Inductance sensing elements
Proceedings of the European Interferometry Initiative Workshop organized in the context of the 20005 Joint European and National Astronomy Meeting "Distant Worlds"
SRON National Institute for Space Research, Sorbonnelaan 2, Utrecht, The Netherlands
Kavli Institute of NanoScience, Faculty of Applied Physics, Delft University of Technology, Delft, The Netherlands
Kavli Institute of NanoScience, Faculty of Applied Physics, Delft University of Technology, Delft, The Netherlands
SRON National Institute for Space Research, Sorbonnelaan 2, Utrecht, The Netherlands
Kavli Institute of NanoScience, Faculty of Applied Physics, Delft University of Technology, Delft, The Netherlands
SRON National Institute for Space Research, Sorbonnelaan 2, Utrecht, The Netherlands
SRON National Institute for Space Research, Sorbonnelaan 2, Utrecht, The Netherlands
Abstract
One of the greatest challenges in the development of future space based instruments for sub-mm astronomy is the fabrication of very sensitive and large detector arrays. Within this context we have started the development of Microwave Kinetic Inductance Detectors (MKID's). The heart of each detector consists of a high Q superconducting quarter wavelength microwave resonator. As a result it is easy to multiplex the readout by frequency division multiplexing. The flexibilty of the MKID allows for radiation detecting from the sub-mm to the X ray by choosing a suitable radiation absorber or antenna. The predicted sensitivity of the MKID is below NEP _ 1 - 10-20W/pHz, low enough for any envisionable application in the sub-mm, optical and X ray wavelength ranges. We describe our initial experiments with these resonators, made of 100 nm Nb films on a high purity Si substrate. We measure the Q factors of several resonators using a vector network analyzer and find Q factors up to 90.000, limited by the intrinsic quality of the Nb resonator.