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CCAT-prime Heterodyne Array Instrument

Layout of CHAI instrument being built at Universität zu Köln.


The CCAT-prime Heterodyne Array Instrument (CHAI) is a modular, dual-frequency band array receiver, which in the first-light configuration covers the scientifically most important parts of the 460 GHz (600 μm, band L) and 830 GHz (370 μm, band H) atmospheric windows for simultaneous observations with 64-pixel arrays each. This is substantially larger than any of the few heterodyne array instruments presently in operation. The design is driven by modularity (for near term and future extensions and upgrades) and the appropriate compromise between best sensitivity on the one hand and simplicity, as well as reliability of the per-pixel components on the other hand. The baseline design matches major parts of the CCAT-prime science goals for high spectral resolution, i.e. heterodyne, instrumentation at first light, with important further ones reachable within the goal specification and through future upgrades at modest effort due to the modularity of the design.

Specifications LFA HFA
RF range [GHz] 455 - 495 800 - 820
Noise temperature(DSB) [K] <100 <200
IF band [GHz] 4 - 8 4 - 8
Resolution [kHz]/[km/s] 100/0.06 100/0.04
Velocity coverage [km/s] 2500 1500
Beam size ["] 26 15
Field of view ['x'] 7.5 x 7.5 4.5 x 4.5