Latest Images of SCUBA-2
3-D CAD representation of the SCUBA-2 cryostat.
3-D CAD representation of the SCUBA-2 cryostat.
The cryostat will weigh about 2500Kg and has a volume of ~ 2.5 x 3 m.
Deep etching of a sub-array test wafer
Deep etching of a sub-array test wafer.
The trenches between the light-coloured pixel areas and the dark walls are 10 microns wide and 100 microns deep. The pixel is supported by a silicon nitride membrane which provides the thermal isolation between the detector and the heat sink.
SCUBA-2 sub-array (40 x 40 pixels) test wafer.
SCUBA-2 sub-array (40 x 40 pixels) test wafer.
This wafer has been etched to a depth of 280 microns, leaving a 100 micron silicon membrane supported by 50 micron thick silicon walls.
SCUBA-2 unit cell multiplexer.
SCUBA-2 unit cell multiplexer.
Each SCUBA-2 pixel has a multiplexer unit cell (~1 x 1mm) as shown in the picture. The change in current through the TES detector is read out using a SQUID amplifier on the MUX wafer. Multiplexing is necessary because of the large number of pixels in the arrays.
3-D CAD representation of the SCUBA-2 on the JCMT.
3-D CAD representation of the SCUBA-2 on the JCMT.
The red beam envelope is shown from the tertiary mirror along an almost 20m optical path, through the elevation bearing, to the cryostat.