Prototype detector technology for the SCUBA-2 submillimetre bolometer array

This paper reports the latest design and the associated fabrication technology of the Mk II prototype infrared (IR) detector for the two 5120 pixel SCUBA-2 (submillimetre common user bolometer arry) instruments, which are to be mounted on the James Clerk Maxwell telescope (JCMT) in Hawaii. Progress is described on the design and the technology modules being developed for the new detector, which is based upon silicon micromachining. The two arrays of transition edge sensors (TES) are used to detect incoming radiation with wavelengths of 450 and 850 μ respectively and as the SCUBA-2 detector operates at about 100 mK, it consequently involves integration with low-temperature electronics and careful design of the associated interconnect. A key aspect of the connection between the TES detector and readout electronics is the use of indium flip-chip bumps, which become superconducting at cryogenic temperatures. The integration of nanoscale membranes and transition edge sensors together with microsystem technology enables SCUBA-2 to have of the order of 10 ^-17W (1 Hz bandwidth) sensitivity to incoming radiation.