Abstract

There is significant interest in sub-millimetre and far-infrared astronomy in ‘on-chip’ spectrometers, where dispersion is achieved using a signal-frequency filter bank integrated onto the same chip as the detectors. On-chip spectrometers realised using Kinetic Inductance Detectors (KIDs) – a type of ultrasensitive, easily multiplexed, superconducting detector – are expected to allow the realisation of large format imaging arrays where each pixel is also capable of wide-band, medium resolution, spectroscopy. This is seen as revolutionary technology for galactic surveys, Cosmic Microwave Background (CMB) studies and intensity mapping in astronomy, and may also be useful for earth observation and atmospheric science. In addition, on-chip spectrometers are more compact and rugged than their competing technologies, making them ideally suited for balloon and space-borne missions. In this talk we will describe the Green Land Telescope (GLT) and our work on the CAMbridge Emission Line Surveyor (CAMELS), a pathfinder instrument that will demonstrate on-chip spectrometer technology operationally. CAMELS will cover the frequency range 103-114.7 GHz at a resolution of R=3000, with the primary science target being 13CO(1-0) and 12CO(1-0) line emission from galaxies at redshift 0.005-0.12. CAMELS will be operated on the GLT during its commissioning phase at Thules Air Force Base, in collaboration with the Harvard Smithsonian Center for Astrophysics. Much of the current work on on-chip spectrometers is focused on the technological aspects of the filter banks. However, a major driver for CAMELS is to understand how to make science grade observations with this technology, i.e. under the idiosyncrasies of operating KID spectrometers at a telescope and how to calibrate the flux and frequency response.