Construction of SPIRAL

The following images show some of the stages in the construction of SPIRAL.

Figure 1: The photograph shows David Lee and Cesar de Oliviera preparing the optical fibres in the AAO library. The library is the only room in the building long enough to accommodate the full 18m length. Each fibre is measured and then cut to the correct length. In all there are 16 groups of 34 fibres with the fibres inserted into small protective tubes.

Figure 2: The 16 groups of fibres are inserted into the protective conduit (the large black tube). The grey box and the smaller diameter conduit belong to SPIRAL-A.

Figure 3: The AAO laboratory where the optical fibres are polished. The blue machine on the right of the photograph is the polishing machine. The polishing jig which we use to polish the small slitlets can be seen near the centre (the circular metal object). During polishing the fibres are regularly inspected using the microscope. Polishing proceeds in the following order: 2000 grit wet and dry paper, 6 micron diamond slurry on a copper plate, 1 micron diamond slurry on a tin/lead plate, and finally colloidal silica solution on a chemical cloth.

Figure 4: The output slit polishing jig. A slitlet can be seen mounted in the centre of the polishing jig. The slitlet contains 32 fibres in a linear array. The spacing between the fibres is 115 microns.

Figure 5: The completed SPIRAL output slit. The slit contains 16 slitlet blocks which can be removed individually for repair or replacement. The slit is 60mm long.

Figure 6: This photograph shows the strain relief box. The box contains a loop of optical fibre which can move freely in and out of the conduit. This is required as the conduit may change length when in moving around on the telescope.

Figure 7: The prototype input array and polishing jig. The input array, which contains a grid of 32x16 optical fibres, is the rectangle within the polishing jig.

Figure 8: The SPIRAL input array during application of the adhesive. The black tube is the conduit. The red furcation tubes contain the optical fibres. The fibres are the brown threads that enter the input array.

Figure 9: The input array. The lower brass plate is the microhole array. The upper brass plate is used to support the metal ferrules. Each ferrule contains a polyimide tube and the fibre is within the polyimide tube. The fibres can be seen protruding from the bottom of the microhole array. The adhesive (Epotek 301-2) is poured into the plastic container to secure the fibres in place.

Figure 10: David Lee removing excess glue from the input array (note the large file!) prior to polishing.

Figure 11: The fibre input array after polishing prior to attaching the microlens array. The fibres are the coloured dots and all 512 can be seen illuminated. This photograph was taken by illuminating the fibres at the output slit through coloured glass filters. Note the excess glue around the edges of the array.

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dl@aaoepp.aao.gov.au 19-March-2000