The THOR-project studied socioeconomic applications for high sensitivity detectors of the terahertz THz (or far infrared) frequency range (100GHz-5THz). The basis for such detectors was founded by the ERC StG grant Teramix, where principles for the detector material (superconducting magnesium diboride , MgB2 ) growth, detector fabrication and performance demonstration were worked out. Combination of both Teramix and THOR projects results in a practical detector which, in contrast to preceding technologies, combines high sensitivity, moderate cooling requirements, greatly increased instantaneous bandwidth.
Applications for terahertz wave applications range from complex high spectral resolution astronomical receivers to compact/portable detection systems for gas and solids spectroscopy. Utilization of MgB2 superconducting films allows to combine high sensitivity of superconducting THz sensors, yet without bully cryogenic coolers. Normally, superconducting devices require cooling down to 4K, which is possible only using large a heavy systems. Developed MgB2 films have a critical temperature of 35K, hence being suitable for much more compact 30K coolers. Such coolers can be classed as handheld. During THOR project we performed prototyping of such a compact system. We have analyzed the marked of the coolers, designed a suitable compact vacuum chamber, fabricated a set of THz sensors. Such sensors were tailored just for the aforementioned 30K cooling systems. This work was driven mainly by THz radiometer application on small satellites, where both payload weight and power consumptions are of critical importance.
During 2018, a proposal for the Origins Space Telescope (a NASA Decadal Survey Mission Concept Study) has been submitted with participation of an EU consortium. This proposal describes possible design concepts for THz astronomical instrumentation, aiming for launching after 2030. In particularly, concepts for extension of the mission operation using space qualified cryocoolers were analyzed. Advantages, which MgB2 HEB THz sensors offer are reduction of the cooler weight (operation at 20K instead of 4K), and greatly increased observation bandwidth as compared to any other alternative sensors.
