Z-Spec: a broadband, direct-detection, millimeter-wave spectrometer
Z-Spec is a broadband (195 - 310 GHz), direct-detection, millimeter-wave spectrometer with moderate resolution (R ~ 350) that we are building to observe CO rotational lines and atomic fine-structure lines in the recently discovered population of submillimeter galaxies. A large fraction of these sources cannot be identified optically and thus redshift determination is extremely difficult. The large instantaneous bandwidth of Z-Spec will allow measurement of redshifts up to z~4 via detection of two or more CO lines in a single spectrum. The spectrometer is based on a parallel-plate waveguide grating architecture that is substantially more compact than a conventional free-space grating system. The spectrometer and an array of 160 silicon nitride micromesh bolometers will be cooled to 100 mK to provide background-limited sensitivity. In addition to measuring the redshifts of sources discovered in submillimeter continuum surveys, Z-Spec will demonstrate a novel spectrometer concept well-suited for future far-infrared space missions.
Additional Information© 2003 Society of Photo-Optical Instrumentation Engineers. We are grateful to Peter Siegel at JPL for his generous help with the prototype spectrometer testing. We would like to acknowledge support from the JPL Directors Research and Development Fund, sponsored by NASA. Jason Glenn also acknowledges NASA (NAGS-11911) and The Research Corporation (RI0928). C. Matt Bradford is supported in part by a Millikan Fellowship at CIT.
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