Design and performance of the 600-720 GHz ALMA band 9 cartridge

The ALMA band 9 cartridge is a compact receiver unit for the Atacama large millimeter array (ALMA) containing the core of a 600-720 GHz heterodyne front end, including a solid-state local oscillator; broadband SIS mixers; and a 4-12 GHz IF amplifier chain. This paper describes the design and performance of the first band 9 cartridge. The experience gained with this unit is being used to optimize the design in preparation for the production of sufficient cartridges to fully populate the ALMA and ALMA compact arrays (ultimately requiring roughly 80 cartridges).