The composite infrared spectrometer (CIRS) instrument, an important component of the Cassini mission, consists of 3 focal plane arrays for sensing IR radiation of the Saturnian planetary system. Goddard Space Flight Center has fabricated, tested, and delivered high performance, 10- element HgCdTe photoconductive (PC) arrays for use on CIRS FP3, the focal plane responsible for detection of radiation in the 9.1 to 16.7 micrometers spectral band. The delivered flight array has peak responsivity 100 percent above CIRS specification, detectivity 30 percent or more above specification, and a cutoff wavelength of 17.3 micrometers at the operating temperature of 80 K. In order to achieve high performance at low frequency while maintaining limited power dissipation, we adopted a split-geometry detector structure. This design also ensured the buttability of the PC arrays to photovoltaic arrays supplied by CE-Saclay-France for detection of radiation in the 7.1 to 9.1 micrometers range. The detector structure is also noteworthy for its use of 0.05 micrometers Alumina powder-loaded epoxy to minimize reflection at the epoxy/HgCdTe interface, thus spoiling undesired optical resonance. This was done in order to meet the CIRS spectral uniformity requirement, which would have been difficult at these long wavelengths without this feature.