ASTID

Submillimeter Gas Analysis for Life Detection

PI: Brian Drouin

This project will build a high sensitivity gas analyzer with absolute specificity to nearly all gas phase species. The instrument will be lightweight, modest mass and power and will be ready for deployment into the field immediately following this development. The novel concept is a streamlined version of the powerful technique of submillimeter spectroscopy which has been widely used for characterization of gas phase species via their rotational, torsional and/or magnetic spectra. All molecules with a dipole or magnetic moment exhibit unique absorptions at long wavelengths. In the submillimeter wavelengths a wide selection of the lightest (hydride) species and heavier (molecular weights up to 120 amu) are accessible within the bandwidth of a single source/detector complement. At JPL high performance, high TRL local oscillators and heterodyne mixers are already available for detection in the (500-2000 um) range. This effort will demonstrate the system integration of these devices with high efficiency optics and a 3-channel narrow band digital receiver (TRL2). Frequency modulated tunable submillimeter radiation will be passed through a compact free-space absorption cell containing samples representative of relevant environments in the earth atmosphere. Heterodyne detection of the simultaneously transmitted on/off peak absorption signals will be detected using fast ASIC signal processors; differential absorption sensitivities near the heterodyne theoretical limit will be demonstrated. Simultaneous measurement of total power enables quantitative analysis. The goals described in the Astrobiology Roadmap – particularly those that require gas measurements and isotopic ratio determination will benefit both scientifically and technically from this new instrument. Scientifically, the new instrument will provide for determination of abundances of previously inseparable and/or indistinguishable trace gases. Finally, through the technology development, this project will demonstrate significant improvements in minimum detectable species concentrations.