Applications of Kinetic Inductance Detectors to Astronomy and Particle Physics

Kinetic Inductance Detectors (KID) have recently drawn the attention of the low-temperature detectors community. High sensitivity, low fabrication complexity, small time constant and most notably the intrinsic capability of frequency multiplexed readout open new possibilities for experiments which need large format arrays of ultra sensitive detectors. In millimeter Astronomy, the New IRAM KID Array (NIKA) instrument is today the most striking demonstration of this. It is a dual band hundreds-pixels KID based camera permanently installed at the focal plane of the IRAM 30-m telescope of Pico Veleta (Granada, Spain). Thanks to the NIKA observational campaigns, we could demonstrate performances comparable to the state-of-art of bolometers operating at the same wavelengths. The instrument is today open to the astronomers community. This encourages further array scaling and opens the path to next generation kilo-pixels ground-based cameras, like NIKA-2. Building on the NIKA experience, we designed a cryogenic KID-camera demonstrator devoted to terrestrial millimeter astronomy in the framework of the AstroKIDs project (Rome, Italy). This activity concerned in particular the realization of a new optical system custom designed for an existing cryostat, as well as the set-up of the cryogenic and the electronic instrumentation needed for the KID operation. The first results showed encouraging performances. The will to extend KID technology to space mission demands a careful investigation of their interaction with the Cosmic Rays (CR). The understanding of the physics of high-energy interactions in the substrate of our arrays is crucial in order to optimize the KID performances in the space environment. In the framework of the European SPACEKIDS project, this led us to implement a fully independent multiplexed readout system for the phonon-mediated particle detection with KID arrays (Grenoble, France). Using radioactive sources to simulate the primary CR hits, we studied the energy propagation induced by such interactions using different substrate solutions and array geometries. The first tests show promising results in damping the phonon propagation over distance and encourage deeper studies. We also made preliminary measurements of the detector performances in terms of time and energy resolution. In Particle Physics, the rejection of the radioactive background is essential for several bolometric experiments, especially for those searching for rare interactions, as neutrinoless double-beta decay (CUORE, LUCIFER, etc.). The development of more sensitive light detectors with a strong multiplexing factor is crucial to achieve the ultra-low background levels required, while ensuring a low impact on existing experiments. The CALDER project (Rome and LNGS, Italy) is a recent R and D in the framework of the CUORE experiment that aims at achieving this goal using the KID technology. Besides providing an alpha background rejection tool for CUORE, high-sensitivity KID-based light detectors could enable the dark matter search with the LUCIFER technique. The work reported through this PhD thesis concerns the development of optimized Lumped Element Kinetic Inductance Detectors (LEKID) and the implementation of dedicated readout techniques for the aforementioned activities. (author)