Optics Resume

M.Carter

2000-10-25

Summary

This is a brief note to bring everyone up on the progress of the optics package. At the Tucson meeting, as reported in the summary given by James Lamb and given by myself at the following telecom meeting of the 2000-10-25, a design was reached. This design is shown below. As described in Jame's summary there are 3 separate styles for the optics.

1. Bands 1 and 2; Consist of a cooled horn an ambient lens, which will probably be the cryostat vacuum seal.
2. Bands 3 and 4; Consist of a horn at 4K, cooled lens probably at 77K, an ambient elliptical mirror, and a flat pick off mirror.
3. Bands 5-10; Consist of horn and OMT for 5 and 6, horns plus quasioptical polarisation splitting for bands 7-10, which will be followed by a train of mirrors which will put the telescope waist at the surface of the cryostat. These different designs will be determined by the different cartridge groups.

Since then I have tried to make this design more concrete with the help of Mark Harman, Bernard Lazareff and Wes Grammer. The design is shown in figures below.

There are some differences from before. The main one is that Mark has been able to increase the diameters of the bands 3 and 4 cartridges to 140 mm. He has done this by moving them into a 335mm radius and rotating them by 10 degrees in the direction of the WVR.

Figure 1 optics with cartridges with 4K plate, but no Dewar top

Figure 2 as figure 1