Development of ALMA Band 8 (385-500 GHz) Cartridge

We have developed a cartridge-type receiver covering from 385 to 500 GHz for pre-production of ALMA Band 8. It receives two orthogonal polarizations and down-converts the sideband-separated signals to intermediate frequencies (IF) between 4 and 8 GHz. The cartridge-type receiver consists of a cold optics, a feed horn, an OMT, two sideband-separating SIS mixers, cryogenic multipliers of local oscillator (LO). These components were individually tested and then the cartridge was integrated and tested as a complete assembly. We have also developed equipment to test both components and the integrated receiver. The single sideband (SSB) noise temperature of this receiver is 130 K at the band center and 180 K at the band edges. The beam pattern and cross-polarization pattern are consistent with physical optical calculation. These results are promising for receiver production to the Atacama Large Millimeter/submillimeter Array (ALMA).