- Conference date: 20–24 July 2009
- Location: Stanford (California)
Noise performance is one of the most crucial aspects of any detector. Superconducting Microwave Kinetic Inductance Detectors (MKIDs) have an “excess” frequency noise that shows up as a small time dependent jitter of the resonance frequency characterized by the frequency noise power spectrum measured in units of Recent studies have shown that this noise almost certainly originates from a surface layer of two‐level system (TLS) defects on the metallization or substrate. Fluctuation of these TLSs introduces noise in the resonator due to coupling of the TLS electric dipole moments to the resonator’s electric field. Motivated by a semi‐empirical quantitative theory of this noise mechanism, we have designed and tested new resonator geometries in which the high‐field “capacitive” portion of the CPW resonator is replaced by an interdigitated capacitor (IDC) structure with 10–20 μm electrode spacing, as compared to the 2 μm spacing used for our more conventional CPW resonators. Measurements show that this new IDC design has dramatically lower TLS noise, currently by about a factor of ∼29 in terms of the frequency noise power spectrum, corresponding to an improvement of about a factor of in NEP. These new devices are replacing the CPW resonators in our next design iteration in progress for MKIDCam. Opportunities and prospects for future reduction of the TLS noise will be discussed.
- Microwave detectors
- Microwave spectra
- Superconducting detectors
Daniel Baumann, Mark G. Jackson, Peter Adshead, Alexandre Amblard, Amjad Ashoorioon, Nicola Bartolo, Rachel Bean, Maria Beltrán, Francesco de Bernardis, Simeon Bird, Xingang Chen, Daniel J. H. Chung, Loris Colombo, Asantha Cooray, Paolo Creminelli, Scott Dodelson, Joanna Dunkley, Cora Dvorkin, Richard Easther, Fabio Finelli, Raphael Flauger, Mark P. Hertzberg, Katherine Jones‐Smith, Shamit Kachru, Kenji Kadota, Justin Khoury, William H. Kinney, Eiichiro Komatsu, Lawrence M. Krauss, Julien Lesgourgues, Andrew Liddle, Michele Liguori, Eugene Lim, Andrei Linde, Sabino Matarrese, Harsh Mathur, Liam McAllister, Alessandro Melchiorri, Alberto Nicolis, Luca Pagano, Hiranya V. Peiris, Marco Peloso, Levon Pogosian, Elena Pierpaoli, Antonio Riotto, Uroš Seljak, Leonardo Senatore, Sarah Shandera, Eva Silverstein, Tristan Smith, Pascal Vaudrevange, Licia Verde, Ben Wandelt, David Wands, Scott Watson, Mark Wyman, Amit Yadav, Wessel Valkenburg and Matias Zaldarriaga
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