The Neel IRAM Kinetic Inductance Array - NIKA
Staff: Simon Doyle, Enzo Pascale, Peter Ade and Carole Tucker Postdocs: Aurelien Bideaud and Edgar Castilo Main collaborators: Alessandro Monfardini and Alain Benoit (Institut Néel MCBT, Grenoble)
The IRAM 30m telescope located on Pico Veleta near Granada in Spain at an altitude of 2920m above sea level.
Led by the Neel Institute (Grenoble, France), the Neel IRAM kinetic inductance array (NIKA) is a collaboration between several European partners to build the next generation, large format millimeter camera for the IRAM 30m telescope.
The camera will consist of three arrays of detectors - one 1000 pixel array observing at 2.1mm and two polarisation sensitive 4000 pixel arrays observing at 1.2mm. To meet the demanding detector requirements of this project, NIKA will use the Lumped Element Kinetic Inductance Detectors (LEKIDs).
LEKIDs were pioneered by the Cardiff Astronomy Instrumentation Group (AIG) who are now responsible for LEKID design specific to the NIKA project as well as detector testing and characterisation. The AIG are also responsible for providing various optical components to the NIKA project such as filters and anti-reflection coated lenses.
Several arrays have been tested in the Cardiff kinetic inductance test facility. This unique facility is fitted with a blackbody light source that can simulate the light we would expect to see from the IRAM telescope in terms of wavelength (selected by filters) and power (controlled by temperature).
The overall aim of the detector development for NIKA is to reach what is know as the photon noise limit in large multiplexed arrays with good optical efficiency. This is the fundamental limit to any optical detector system and increases as the optical power incident on the detector is increased. In recent test of LEKID arrays for NIKA there is strong evidence that we have reached this limit for the expected optical power loads one would expect from the skies over the IRAM 30m telescope.
The NIKA collaboration has already successfully tested several prototype LEKID arrays on the IRAM 30m telescope. The latest prototype was tested in June 2013 and consisted of 2 detector arrays - a 224 pixel array observing at 1.25mm and a 132 pixel array observing at 2mm. More information on the NIKA project can be found on the NIKA webpages.
In parallel to the instrumentation work, other members of the Astronomy and Astrophysics Group at Cardiff University are currently undertaking leading roles in the scientific exploitation of the data that will be collected with this millimeter camera.
Left: A 196 pixel 150 GHz LEKID array designed for the NIKA instrument. Each square patch on the silicon wafer is a detector. The entire array is cooled to 100mK (0.1K) and all 196 detectors read out via the two SMA connectors. Right a 2mm image taken on the 6th run of the NIKA prototype camera in June 2013 of the supernova remnant Cassiopea A.