Single Pixel Performance of the Kinetic Inductance Detectors for the Terahertz Intensity Mapper

The Terahertz Intensity Mapper (TIM) is a NASA far-infrared balloon mission designed to perform [CII] intensity mapping of the peak of cosmic star formation. To achieve this goal, TIM will fly two grating spectrometers that together cover the 240–420 μ m wavelength range at a spectral resolution, R∼ 250. Each spectrometer will require a large format (∼ 3600 detectors) array of dual-polarization sensitive detectors, which are photon noise limited at the 100 fW of loading expected during operation. We present the design of a fully-aluminum low-volume lumped-element kinetic inductance detector that incorporates a novel “chain-link” absorber design. Operating at 215 mK, we demonstrate this detector achieves a photon noise limited performance at 100 fW of optical loading with a white noise spectrum down to 1 Hz. Based upon noise measurements of a dark detector, which shows a quasi-particle lifetime of 300μs, these KIDs are expected to achieve a detector-limited noise equivalent power of ∼1.3×10-18W/Hz.