Boulder

1. Boulder SCUBA-2: The next generation bolometer camera for the James Clerk Maxwell Telescope 2 Array development William Duncan Kent Irwin Alan Gundlach

2. Array Development 2 Choice of detectors and collaborative efforts - WDD TES and SQUID mux. technologies - Kent Irwin University of Edinburgh Micro-machining fabrication facilities - Alan Gundlach

3. Array Development 2 • DC coupled filled arrays for SCUBA 2 • versus SCUBA arrays • much higher mapping speed • better systematics • no need to chop or jiggle • image reconstruction much easier

4. Array Development 2 • What technology? IF large field & /Fλ sampling = large number of pixels - 30 to 40 thousand • Therefore must have detectors which may be multiplexed and may be produced by Si fabrication and photo-lithographic techniques

5. Array Development 2 Eliminates NTD type detectors as used on SCUBA - no multiplex capability Leaves two array technologies, both under development for SPIRE - TES detectors and the Saclay group’s ion implanted sensors TES detectors are our baseline choice, given demonstrated performance at x-ray, uv - ir and early results on SPIRE. Maintain watch on Saclay developments.

6. Metal absorber 5mm Si grid Reflector l/4 cavity FIRST-SPIRE: CEA-SACLAY/LETI MICROMACHINED ARRAY OPTION, ADOPTED FOR TES USE Mechanical/thermal/electrical link TES Absorbing metal film l/4 cavity Silicon substrate Reflector Silicon grid 0.3 K 50 mm • Silicon grids with resonant absorbers 400 mm TES 0.3 K Absorbing grid Reflector Indium bumps

7. SCUBA 2 Array architecture Potential configuration Array S. Mux Wire bonds or kapton cable ¼λ gap [Or S. Mux on reflector chip] Bump bonds Reflector/interconnect chip

8. SCUBA 2 Array production Agreement/Funds Devices/mux electronics Science NIST SCUBA 2 project Si structures LTTP Grant for Si micro-machining ~ 4+ years